P-38 Compared to Me-110
peter wezeman
among other things, achieve air supremecy over enemy territory. It was
a complete failure in this role, although it went on to some success
as a night fighter.
The Lockheed P-38 Lightning was essentially the airplane that the
Me-110 was meant to be. It was the only twin-engine fighter to
take on and defeat single engine fighters, even though the P-38
was originally developed as an interceptor to shoot down bombers.
Leaving aside the virtues of the zerstorer concept, I note that
developed versions of both fighters were very similar in many
respects. Comparing the Me-110G to the P-38J, the Me-110 had
1,355 hp per engine at 18,700 ft, a wing span of 53 feet, and
a gross weight of 20,701 lb. The P-38 had 1,425 hp per engine at
26,500 feet, a wing span of 52 feet, and a weight of 17,500 lb.
However, the maximum speed of the Me-110G was only 342 mph compared
to 414 mph for the P-38J. The Me-110 had more wing area than the
P-38, but less than the Mosquito.
Clearly, the Me-110 had some extra drag compared to the P-38. Was
it coming from the wing profile? Cooling system? Interference?
Some combination of factors? It does appear that the P-38 has
a more sophisticated system of handling the cooling air than the
Me-110.
Thank you,
Peter Wezeman
anti-social Darwinist
Jukka O. Kauppinen
> it coming from the wing profile? Cooling system? Interference?
> Some combination of factors? It does appear that the P-38 has
> a more sophisticated system of handling the cooling air than the
> Me-110.
When comparing 110 G model to P-38 we must take into account, that the
mentioned top speed seems to be the top speed of 110G night fighter.
The night fighter had 3 men crew, rear facing defensive weapons, nose
weapons and schrage music cannons, radar, radar antennas in the nose,
flame extinguishers and so on.
It was meant to a completely different work and environment than P-38,
and was not only heavier but carried much more equipment. And that
causes drag and slows down the plane by very big margin. The speed was
enough against their opponents - night bombers and it wasn't even meant
to be used against during day.
jok
Jukka O. Kauppinen
> it coming from the wing profile?
A few pictures for more reference:
http://www.214th.com/ww2/germany/me110/me110d.jpg
http://www.214th.com/ww2/germany/me110/me110e.jpg
http://www.214th.com/ww2/germany/me110/me110f.jpg
jok
John Halliwell
wezeman <peterw...@hotmail.com> writes
>The Lockheed P-38 Lightning was essentially the airplane that the
>Me-110 was meant to be. It was the only twin-engine fighter to
>take on and defeat single engine fighters, even though the P-38
>was originally developed as an interceptor to shoot down bombers.
The above statement requires some clarification though. Mosquito 'night'
fighters had considerable success downing FW190s running for the French
coast, both at night and in poor weather. Just one example, there are
probably many more.
Comparisons between the Bf110 and Lightning are understandable and
always seem to turn up differing views. The Lightning was a cleaner
aircraft with a smaller crew and a later design. The original Lightning
Is issued to the RAF weren't up to much and were rejected.
--
John
Preston, Lancs, UK.
Walt BJ
and 'handed' engines and were known as 'castrated' P38s. The P38's
major probles were compressibility which came on at about .75M (.11
below the Spitfire)(retrofit dive brakes alleviated this) and poor
defrosting and cabin heat leading the windows to frost over on a fast
descent. Not good, in combat. A skilled pilot could take advantage of
the P38's good points - an ability to turn either way at high speed
because of handed engines, concentrated fire power, and maneuver flaps
which with a full power prop stream across them gave the 38 great
low-speed maneuver characteristics. OTH maintenance was a free
wheeling PITA; the engines were closely cowled and the suspension
beams left little space for a big hand. I examined Kermit Weeks's 38
and could see where mechs with little hands would be at a premium. One
remark about the Me110 - it had things hanging out all over (tail
wheel, two masts, two loop antennae, aileron counterbalances) plus
draggy underwing radiators which all slowed the beast down. And it did
not have 'handed' props.
Walt BJ
Cub Driver
>
>Clearly, the Me-110 had some extra drag compared to the P-38
Well, there was the glass greenhouse and the rear gunner.
There was a lot of stuff hanging out. The Bf-109 was after all a 1934
design, while the P-38 was specced out two years later. This was a
time of very rapid development in warplanes, especially fighters. Did
the 109's tailwheel even retract?
Perhaps it would be fairer to compare it with the contemporary Bell
FM-1 Airacuda.
As a night fighter, where it didn't have to maneuver against enemy
fighters, the 109 fared very well, with 6,000 built.
all the best -- Dan Ford (email: cub06h AT eudoramail.com)
see the Warbird's Forum at http://www.danford.net
Vietnam | Flying Tigers | Pacific War | Brewster Buffalo | Piper Cub
Emmanuel.Gustin
: The Messerschmitt Me-110 was developed as heavy, long range fighter to,
: among other things, achieve air supremecy over enemy territory.
In so far as the role of the Bf 110 was defined during its
development (there was a fair amount of confusion, and
Messerschmitt ignored the official specifications) it
was intended as a heavy interceptor, rather than as a
long-range offensive fighter. It also had a secondary
roles as fighter-bomber.
: The Lockheed P-38 Lightning was essentially the airplane that the
: Me-110 was meant to be. It was the only twin-engine fighter to
: take on and defeat single engine fighters, even though the P-38
: was originally developed as an interceptor to shoot down bombers.
That is a bit exaggerated. Fighter Mosquitoes had some success
against Fw 190s, the Westland Whirlwind was a good dogfighter,
and the Ki-45 could out-turn a P-38 with some ease. However,
most twin-engined fighters were designed to be heavier than
a P-38, and carry bigger loads and more equipment. The P-38
was effective against single-engined fighters (if the right
tactics were used) but on the other hand it offered few of the
additional flexibility for which other twin-engined fighters
were designed; it wasn't a good nightfighter and you could
hardly hang a torpedo or similar loadings onto a P-38. It was
very much a matter of design priority; if the Luftwaffe had
wanted a P-38 it would have chosen the Fw 187 over the Bf 110.
Emmanuel Gustin
John Halliwell
<wal...@mindspring.com> writes
>The Lightning Is for the RAF were delivered without turbosuperchargers
>and 'handed' engines and were known as 'castrated' P38s. The P38's
>major probles were compressibility which came on at about .75M (.11
>below the Spitfire)(retrofit dive brakes alleviated this) and poor
>defrosting and cabin heat leading the windows to frost over on a fast
>descent. Not good, in combat.
I appreciate the difference in the engines, my references suggest
because the higher spec engine wasn't cleared to be exported to the UK.
I don't know why it was seen to be so important to restrict the
Lightnings in this way. Had proper P-38s arrived and been put into
service, there's a good chance that the RAF would have had a chance to
work them up in a combat role, possibly providing valuable feedback.
Gregory W Shaw
> That is a bit exaggerated. Fighter Mosquitoes had some success
> against Fw 190s, the Westland Whirlwind was a good dogfighter,
> and the Ki-45 could out-turn a P-38 with some ease. However,
> most twin-engined fighters were designed to be heavier than
> a P-38, and carry bigger loads and more equipment. The P-38
> was effective against single-engined fighters (if the right
> tactics were used) but on the other hand it offered few of the
> additional flexibility for which other twin-engined fighters
> were designed; it wasn't a good nightfighter and you could
> hardly hang a torpedo or similar loadings onto a P-38. It was
> very much a matter of design priority; if the Luftwaffe had
> wanted a P-38 it would have chosen the Fw 187 over the Bf 110.
>
> Emmanuel Gustin
Lockheed was testing a P-38F-13-LO carrying two Mk 13 torpedoes in late
'42. Or a single Mk 13 and a 300 gal drop tank to a radius of over 1000
miles. If the USAAF had wanted a torpedo bomber it was certainly capable
of filling that role, at least as good if not better than a Beaufighter
or Beaufort.
Warload compared very favorably to any other twin engine fighter. Most
of the FB Mosquito marks were limited to 4 x 500 lb bombs and their
performance wasn't as good as any P-38.
The P-38 was easily capable of carrying a pair of 500 lb, 1000 lb or
even 2000 lb bombs externally. But that wasn't their role, they were the
only long range fighter available for the first two years of the war and
that was more important than having another bomb hauler. The USAAF
already had the A-20, B-25 and B-26 on one end of the spectrum and the
P-39 and P-40 on the other.
The P-38's biggest limitation was internal volume. As Walt mentioned, it
was extremely tight and there simply wasn't room for an effective radar
and a second crewman as a radar operator. The P-38M was too crowded and
the radar wasn't as effective as the larger sets on the P-61 and
Mosquito. So it did lack some of the versatility of the other twin
engined fighters, but the tradeoff was it made a better long-range day
fighter and interceptor than they did.
Greg Shaw
Chris Mark
> you could
>hardly hang a torpedo or similar loadings onto a P-38.
Well, I had lunch yesterday with some veterans of the MTO and one of the topics
that came up was the raid by P-38s on Italian warships in Sardenia in the
spring of 1943. They used thousand pounders, flying over from Africa.
Apparently knocked out a cruiser.
As a point of fact, the AAF was never much interested in torpedos, preferring
bombs and mines as well as strafing, including cannon fire, against seaborne
targets.
Chris Mark
Gordon
>The Messerschmitt Me-110 was developed as heavy, long range fighter to,
>among other things, achieve air supremecy over enemy territory. It was
>a complete failure in this role, although it went on to some success
>as a night fighter.
The Bf-110 series nightfighter scored more night victories than any other type
of aircraft. That is "some success".
>Leaving aside the virtues of the zerstorer concept, I note that
>developed versions of both fighters were very similar in many
>respects. Comparing the Me-110G to the P-38J
The 110 was old and heading towards obsolete before the war began; throughout
the war, it was an old whore dressed up in new makeup periodically. Only at
night and away from the predatory RAF nightfighters were they able to use their
limited capabilites to maximum advantage, against large, slow heavy bombers.
The P-38 shared none of the disadvantages of the earlier Zerströyer.
v/r
Gordon
<====(A+C====>
USN SAR Aircrew
"Got anything on your radar, SENSO?"
"Nothing but my forehead, sir."
Walt BJ
> very much a matter of design priority; if the Luftwaffe had
> wanted a P-38 it would have chosen the Fw 187 over the Bf 110.
>
Oops. I have a picture of a P38 with two torpedoes slung under the
wings. It also could carry a pair of 2000 pound bombs. There was a
'DroopSnoot' model with a Norden bombsight or 'Mickey' radar bombing
gear plus a bombardier in the nose. The DroopSnoot would lead a
formation of bomb -laden fighters and upon signal from the bombardier
the fighters would salvo their one-ton bombs. There was also a
nightfighter model (P38M) with the RIO piggybacked behind the pilot.
It was used late in the war in the Pacific. The above information is
from Willaim Green's 'Famous Fighters of WW2', Vol I. Where the 38
really shone was range - I knew several pilots who flew photorecce in
them - 8 to 10 hour missions over the Pacific and China. FWIW one of
the 38's more effective combat maneuvers was a cloverleaf, a turning
loop with the direction of turn against the P-effect of the
opposition's fighters. It also had an excellent high speed zoom climb,
plus the armament mounting, like the 110, gave a concentration of
fire.
Walt BJ
Jakob Whitfield
difference in emphasis between the two. The Lightning was designed as
a fighter-interceptor, and worked well as a fighter-bomber. The 110
didn't work as a day fighter due to the tech of the day not really
being up to it, but she made a decent workhorse night fighter.
OTOH, no twin-engined fighter of WWII could outfly a contemporary
single-engined fighter.
As for the Lightnings anti-shipping prowess, I suspect the Torbeau was
better suited for the role, if only because of the second crew member.
The Lightning was a great design, but so cramped she didn't scale up
well.
-J
Kyle Boatright
I disagree with one of your statements, and question another:
1: "OTOH, no twin-engined fighter of WWII could outfly a contemporary
single-engined fighter."
I'd say the P-38 could outfly any of its contemporaries (P-39, P-40, and
early mark Spits and ME's). It could also hold its own against later Spits
and ME's, plus the FW, P-47 and P-51. It had a better ceiling than any of
those aircraft, a better climb rate than most, and a better (or at least
equal) turn radius than any of the other aircraft listed except the Spit.
Some of the aircraft listed did have slight advantages in speed, roll rate,
and/or mach limits. That said, it is hard to say that any one of the top
half dozen piston fighters outflys the others, given different strengths and
weaknesses.
2: " As for the Lightnings anti-shipping prowess, I suspect the Torbeau was
better suited for the role, if only because of the second crew member"
How does a second crewmember help? As far as I know, the pilot aims the
aircraft (and torpedo) and releases the fish.
KB
"Jakob Whitfield" <jakobwh...@hotmail.com> wrote in message
news:4fc9fd0e.02120...@posting.google.com...
Gordon
>better suited for the role, if only because of the second crew member"
>
>How does a second crewmember help? As far as I know, the pilot aims the
>aircraft (and torpedo) and releases the fish.
An extra set of eyes is always good for a role that invariably will include
overwater navigation and quite likely an attack profile that will not allow
much in the way of evasive manuevering - meaning easy prey for any fighter
unless there is some particularly nasty defensive armament, as in the case of
the TBM. A Lightning on that low over the water straight in approach would not
have any ability to defend itself, unless it abandoned its torpedo to fight.
Just as importantly, in the Stringbag and many others, that other man in the
aircraft could give the pilot absolutely necessary directions during combat to
help him evade such inevitable attack.
John Keeney
Chris Mark <xmar...@aol.compost> wrote in message
news:20021208125113...@mb-fq.aol.com...
> >From: "Emmanuel.Gustin" gus
>
> > you could
> >hardly hang a torpedo or similar loadings onto a P-38.
At least one model of the P-38 was equipped for torpedo attack;
I don't have my reference material at hand, but I'm thinking the J.
> Well, I had lunch yesterday with some veterans of the MTO and one of the
topics
> that came up was the raid by P-38s on Italian warships in Sardenia in the
> spring of 1943. They used thousand pounders, flying over from Africa.
> Apparently knocked out a cruiser.
> As a point of fact, the AAF was never much interested in torpedos,
preferring
> bombs and mines as well as strafing, including cannon fire, against
seaborne
> targets.
I hadn't considered that before; the torpedo was a Navy weapon.
Did any USAAF planes ever drop torpedoes?
Keith Willshaw
"Kyle Boatright" <kyle.bo...@adelphia.net> wrote in message
news:VvSI9.4449$VA5.6...@news1.news.adelphia.net...
> Jakob,
>
> I disagree with one of your statements, and question another:
>
> 1: "OTOH, no twin-engined fighter of WWII could outfly a contemporary
> single-engined fighter."
>
The Whirlwind did pretty well as I recall as did the Grumman Tigercat
> I'd say the P-38 could outfly any of its contemporaries (P-39, P-40, and
> early mark Spits and ME's). It could also hold its own against later
Spits
> and ME's, plus the FW, P-47 and P-51. It had a better ceiling than any of
> those aircraft, a better climb rate than most, and a better (or at least
> equal) turn radius than any of the other aircraft listed except the Spit.
> Some of the aircraft listed did have slight advantages in speed, roll
rate,
> and/or mach limits. That said, it is hard to say that any one of the top
> half dozen piston fighters outflys the others, given different strengths
and
> weaknesses.
>
> 2: " As for the Lightnings anti-shipping prowess, I suspect the Torbeau
was
> better suited for the role, if only because of the second crew member"
>
> How does a second crewmember help? As far as I know, the pilot aims the
> aircraft (and torpedo) and releases the fish.
>
Pass but the Beaufighter with air cooled engines could
take a lot more damage than the water cooled engines
of a Lightning and still get home. Many of the Coastal
Command crews flying Beaufighters in the North Sea
were reluctant to trade in their Beaus for Mosquitos for
this reason.
Keith
Greg Hennessy
<keith@kwillshaw_NoSpam.demon.co.uk> wrote:
>
>The Whirlwind did pretty well
Shame about the engines. being the 1st out there with 4 hispano in the
nose, it must have been truly devasating to be on the recieving end of it.
greg
--
$ReplyAddress =~ s#\@.*$##; # Delete everything after the '@'
You got to move it up and use it like a screwball would.
You got to pack it up, work it like a new boy should.
Emmanuel Gustin
news:497f097b.02120...@posting.google.com...
> Oops. I have a picture of a P38 with two torpedoes slung under the
> wings.
Oops indeed. Obviously, I wasn't aware of that one... Of course it
was never used operationally, but maybe nobody could work up
the courage to inform admiral King :-) .
With hindsight, carrying a torpedo under a fighter was not such
an uncommon idea. The Germans were able to fit a 950 kg torpedo
under a Fw 190A with an extended tailwheel, and the FAA tried
to convert the Firebrand "fighter" into a torpedo-bomber.
> There was also a nightfighter model (P38M) with the RIO piggybacked
> behind the pilot.
Yes, but the aircraft wasn't very suitable. There was no room for a
really powerful radar and the other equipment carried by standard
nightfighters. The location of the armament was not very suited for
nightfighting either, and the glowing turbines of the superchargers
contributed to advertise the aircraft's presence. It was the semi-failure
of the P-61 that created the need for this stopgap nightfighter model.
Of course, Lockheed might have designed a new fuselage with
room for two, SCR-720 radar and ventral armament; and in
that form the aircraft would have been an excellent nightfighter.
Unfortunately, when it cames to heavy fighter development the
USAAF went as far astray as the Luftwaffe ever was, as
demonstrated by the XP-58 and P-61.
--
Emmanuel Gustin <Emmanuel.gustin -@- skynet.be>
Military Aircraft Database, Fighter Guns Page on
http://users.skynet.be/Emmanuel.Gustin/
Mick
anti-clockwise
Mick
Gordon
>I hadn't considered that before; the torpedo was a Navy weapon.
>Did any USAAF planes ever drop torpedoes?
B-26s, at Midway, no..? Plenty of AAF aircraft had the ability to drop torps,
just no mission profile requiring it.
Robert Inkol
system seems to suffer from the proximity of the wing. If you look
closely, you will note that the exhaust pipes are curved upwards or
downwards to help the exhaust clear the wing. It would appear that a
significant fraction of the potentially available jet thrust ws lost
due to this arangement. The importance of jet thrust was only
beginning to be realized at the time the Me 110 was designed.
Robert Inkol
peterw...@hotmail.com (peter wezeman) wrote in message news:<7c5510c.02120...@posting.google.com>...
Joe Osman
The 69th Bombardment Squadron (Medium) dropped torpedoes
from B-26 Marauders at Midway.
It says at http://www.afa.org/magazine/valor/0486valor.html
that "Collins and his crews were given sketchy instruction
by the Navy in torpedo bombing, the most nearly suicidal air
tactic of the war,... According to Air Force historians, the
AAF never again sent torpedo-armed bombers into combat."
Later, both the 69th and 70th Bombardment Squadrons
(Medium), which also flew B-26 Marauders, practiced torpedo
bombing, but when they got to Guadalcanal the Navy took all
their torpedos.
The AAF also had some dive bomber squadrons at the beginning
of the war, but dropped the idea because they thought the
planes were too vulnerable during the long dive necessary
for dive bombing.
Joe
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Chris Mark
>>Did any USAAF planes ever drop torpedoes?
>
>B-26s, at Midway, no..? Plenty of AAF aircraft had the ability to drop
>torps,
>just no mission profile requiring it.
Well, the AAF did a fair amount of anti-shipping work, but disdained the
torpedo. One reason might have been that a torpedo weighed what--2,000 lbs?
and carried something like a 300 lb warhead. So why not just skip 500 or 1,000
lb bombs into the sides of ships and get more bang for your trouble?
As for the attack by P-38s on Porto Torres that I mentioned, I personally think
B-25s could have done a better job. Apparently it was the brainchild of the CO
of the 71st fighter squadron (I didn't catch the group). It was a two hour
flight over to Sardinia for a dozen of the P-38s, navigating by dead reckoning.
They stayed at wavetop height until within a quarter mile of the target, then
rose to 1,000 feet to clear terrain which they did with a few feet to spare and
burst out over the harbor at about that altitude over sea level, dove on the
ships at the dock and released their thousand pounders, which had 15
second-delay fuses to make sure everybody was clear before they detonated.
There was an airfield adjacent the harbor filled with Machies which they could
see being scrambled as they completed the bomb run so they turned over and
strafed the field and tangled with a couple of fighters that got airborne.
They lost no planes and did some serious damage to the ships in the harbor.
But a dozen B-25s could have flown that same mission profile and put three
times the bomb tonnage on the target with at least as good if not better
accuracy (the crews being trained to do that sort of thing), and certainly
ripped the shit out of that airfield. No idea why they weren't used except a
guess that there just weren't enough airplanes around at the time for all the
targets needing hit. And some eager beaver CO volunteering his squadron for a
type of mission they haven't trained for....oh, joy. But you got to hand it to
them, their dead reckoning navigation and ability to recognize landmarks as
they approached at sea level based on studying a map--outstanding for a bunch
of 20 year old throttle jockeys.
Chris Mark
Chris Mark
mission the next month a standing patrol of Machis fell on the P-38s and shot
down three, a fourth having an engine shot out but making it home. All bombs
had to be jettisoned, of course, to enable the P-38s to defend themselves. So
surprise was the key to the success of this type of mission. A dozen
unescorted B-25s intercepted by fighters would have also had a tough time, but
I can't imagine them jettisoning their bomb loads and scattering. They would
have just tightened up the formation and bored on in. Probably they would have
taken losses. The answer to that would have been to have forgotten about
surprise and gone in with a fighter sweep ahead of the mediums (to clear out
any fighter patrols), which would have arrived with fighter escort and done
precision bombing from 7,000-10,000 feet on the harbor installations and
shipping in the harbor. Armchair generalship, I realize---the best kind
because reality doesn't interfere with your theorizing. Reality being things
like no fighters available because the heavies have dibs on them, or you get
them but not enough for a fighter sweep and close escort, or you get them but
they miss the rendevous point, or the navigation to the target is crummy
because the lead navigator's plane had to abort, or the weather doesn't
cooperate, or the bad guys corner all the luck that day......
Chris Mark
John Halliwell
<xmar...@aol.compost> writes
>Well, the AAF did a fair amount of anti-shipping work, but disdained the
>torpedo. One reason might have been that a torpedo weighed what--2,000 lbs?
>and carried something like a 300 lb warhead. So why not just skip 500 or 1,000
>lb bombs into the sides of ships and get more bang for your trouble?
Depends a lot on the target. For heavily armoured ships, 500 or 1,000lb
bombs dropped from low altitude and 'skipped' into the sides would have
very little (if any) effect. Even dropped on the deck in a dive bombing
attack might not penetrate the armour.
Torpedoes are different, ideally they'd explode under the keel,
triggered by a magnetic detonator (if indeed it worked), potentially
causing much more damage.
I guess Highball was a combination of the two types of attack, it would
have been interesting to see how it would have worked in operation.
Chris Mark
>Depends a lot on the target. For heavily armoured ships, 500 or 1,000lb
>bombs dropped from low altitude and 'skipped' into the sides would have
>very little (if any) effect.
I suppose that's why the USN stuck with the torpedo, their job being to knock
out just such targets while the AAF didn't do as much of that. Skip-bombing
500 pounders into the side of the Musashi or Yamato probably would have been a
wasted effort.
Chris Mark
Greg Hennessy
>Skip-bombing
>500 pounders into the side of the Musashi or Yamato probably would have been a
>wasted effort.
A free fall HESH/HEP bomb with 500lb of RDX behind it would do a fair job
of knocking spall out of the even thickest armour I would have thought.
AFAIK, the soviets had an ASM with a seriously large shaped charge on the
front for killing carriers. It wouldn't have been beyond the capability of
the US in ww2 to create a free fall HEAT bomb with a meter+ wide cone and
say 2-3000lbs of HE behind it. One of those would kill any battleship gun
turret dead and more than likely cook off secondaries inside it putting it
out of commission permanently.
The HEAT warhead on the german mistel could IIRC penetrate something like
30 feet of steel or 70-80 feet of reinforced concrete . A freefall US
analogue would chew a serious hole in the side of any japanese battlewagon.
John Halliwell
<spamc...@example.com> writes
>A free fall HESH/HEP bomb with 500lb of RDX behind it would do a fair job
>of knocking spall out of the even thickest armour I would have thought.
The FAA used 2,000lb armour piercing bombs, don't think they used
smaller versions?
>AFAIK, the soviets had an ASM with a seriously large shaped charge on the
>front for killing carriers. It wouldn't have been beyond the capability of
>the US in ww2 to create a free fall HEAT bomb with a meter+ wide cone and
>say 2-3000lbs of HE behind it. One of those would kill any battleship gun
>turret dead and more than likely cook off secondaries inside it putting it
>out of commission permanently.
Now we're wandering off topic because a P-38 isn't going to lift it.
Once you put 2-3000lbs in an armoured bomb, you're looking at something
like 7-8000lbs all-up weight (rough guess?). That's a lot of weight to
lift, especially off a carrier. You also lose the ability to drop
accurately (needs a hefty dive bomber), so you limit use to ships that
can't manoeuvre freely. Closest was the Tallboy, 12,000lbs used to sink
Tirpitz (something like a 2,400 mile round trip).
>The HEAT warhead on the german mistel could IIRC penetrate something like
>30 feet of steel or 70-80 feet of reinforced concrete . A freefall US
>analogue would chew a serious hole in the side of any japanese battlewagon.
The Mistel was a Ju-88 with a shaped charge on the front, rather more
than just a freefall bomb. The answer was of course to build a proper
bomb, the Tallboy and Grand Slam wouldn't have had any problems at all.
Michael Williamson
John Halliwell wrote:
> I appreciate the difference in the engines, my references suggest
> because the higher spec engine wasn't cleared to be exported to the UK.
> I don't know why it was seen to be so important to restrict the
> Lightnings in this way. Had proper P-38s arrived and been put into
> service, there's a good chance that the RAF would have had a chance to
> work them up in a combat role, possibly providing valuable feedback.
>
> --
> John
The engines were available (the turbosuperchargers likely would not
have been due to production issues rather than export restrictions),
but the British ordered the 'C' series Allison engines in order to limit
their supply requirements, as they were already being supplied with
P-40s using that model engine. The less powerful engines without
counterrotating propellers caused some performance issues, but
the design did (perhaps) actually meet the British specification.
The greater issue, apparently, was that the specification issued by
the British was found to be inadequate to their needs following the
Battle of Britain. According to Bodie in _The Lockheed P-38
Lightning_, there was enough bad blood developed over the
Lightning I that the British never even evaluated the Lightning II
(with superchargers and counter-rotating propellers) and that their
relationship with Lockheed was soured well past the end of the war.
Mike
Michael Williamson
Mick wrote:
>
> Does "handed props" mean that one engine turns clockwise and the other turns
> anti-clockwise
> Mick
In this case, yes. The props rotate 'outward' at the top when viewed from
behind. The result is that P-factor and any other prop-related aerodynamic
asymmetries tend to cancel out when both engines are developing the same
amount of power.
Mike W
Geoff May
In this instance, yes it does. I must admit, I'd never heard the
expression before, though...
MfG
Geoff.
--
An offline Formula One [tm](r)(c) is available at
http://beateundgeoff.bei.t-online.de/geoff.htm
Last updated on 10th Dec. 2002
For an alternate F1 news group news://news.f1ngers.com/F1NGers
Jdf4cheval
purchasing commission for the RAF's P-38s. I remember him saying that the
pilots adamantly wanted the superchargered version of the aircraft, and were
enormously disappointed that it was a no-go by the British Government.
Greg Hennessy
<jo...@photopia.demon.co.uk> wrote:
>In article <755avushuf8mh0erm...@4ax.com>, Greg Hennessy
><spamc...@example.com> writes
>>A free fall HESH/HEP bomb with 500lb of RDX behind it would do a fair job
>>of knocking spall out of the even thickest armour I would have thought.
>
>The FAA used 2,000lb armour piercing bombs, don't think they used
>smaller versions?
I would have thought that they had to be 2000+lb to have the necessary KE
to pierce armour. A putative freefall HESH bomb with 500lb of RDX inside
wouldn't weigh anywhere close.
>
>Now we're wandering off topic because a P-38 isn't going to lift it.
Why ? Correct me if I am wrong, but I thought that later marks of P38 could
and did carry 2 x 1600lb GP bombs. A HESH freefall bomb with 1000lb of RDX
and 600lbs of case/fuse would admittedly be a lot more bulky than a
traditional AP bomb, however considering the likely effect on even the
thickest deck and turret armour, it wouldn't have been healthy to be on the
recieving end of it.
>
>Once you put 2-3000lbs in an armoured bomb, you're looking at something
>like 7-8000lbs all-up weight (rough guess?).
For an armour piercing KE bomb that would be correct. Case weight on a HESH
bomb would be rather less than the HE within, on a HEAT, most of the weight
would be in the cone I would have thought.
Keith Willshaw
"Greg Hennessy" <spamc...@example.com> wrote in message
news:f5gbvu488bfcliqkp...@4ax.com...
> On Tue, 10 Dec 2002 00:36:24 +0000, John Halliwell
> <jo...@photopia.demon.co.uk> wrote:
>
> >In article <755avushuf8mh0erm...@4ax.com>, Greg Hennessy
> ><spamc...@example.com> writes
> >>A free fall HESH/HEP bomb with 500lb of RDX behind it would do a fair
job
> >>of knocking spall out of the even thickest armour I would have thought.
> >
> >The FAA used 2,000lb armour piercing bombs, don't think they used
> >smaller versions?
>
> I would have thought that they had to be 2000+lb to have the necessary KE
> to pierce armour. A putative freefall HESH bomb with 500lb of RDX inside
> wouldn't weigh anywhere close.
>
HESH doesnt depend on KE and since HESH rounds 5% of that
size could kill tanks nicely it'd seem to be overkill. The only problem is
that
the armor belt is often inside the hull and below the weather deck
so the war head would probably explode at that level and fail
to penetrate the armor belt.
The 2000lb AP bombs could penetrate the decks and then explode
>
> >
> >Now we're wandering off topic because a P-38 isn't going to lift it.
>
> Why ? Correct me if I am wrong, but I thought that later marks of P38
could
> and did carry 2 x 1600lb GP bombs. A HESH freefall bomb with 1000lb of RDX
> and 600lbs of case/fuse would admittedly be a lot more bulky than a
> traditional AP bomb, however considering the likely effect on even the
> thickest deck and turret armour, it wouldn't have been healthy to be on
the
> recieving end of it.
> >
> >Once you put 2-3000lbs in an armoured bomb, you're looking at something
> >like 7-8000lbs all-up weight (rough guess?).
>
> For an armour piercing KE bomb that would be correct. Case weight on a
HESH
> bomb would be rather less than the HE within, on a HEAT, most of the
weight
> would be in the cone I would have thought.
>
Actually the Fritz-x Guided AP bomb could easily penetrate Battleship
armor, sinking the Roma and badly damaging HMS Warspite and
weighed in at around 3500lbs
Keith
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Greg Hennessy
<keith_w...@compuserve.com> wrote:
>HESH doesnt depend on KE and since HESH rounds 5% of that
>size could kill tanks nicely it'd seem to be overkill.
With a yamato sized threat it may be prudent to err on the side of overkill
:-). One would have also expected such a weapon to do a serious number on
concrete fortifications etc.
>The only problem is that the armor belt is often inside the hull and below the weather deck
>so the war head would probably explode at that level and fail
>to penetrate the armor belt.
True. Multiple HESH hits of that size exploding on deck and main gun
turrets may have at least caused a mission kill I would have thought,
combined with large free fall shaped charges for penetration. 3-500kg of
copper/whatever liner as a plasma or SFF would have had serious amount of
KE and spalling potential for causing damage deep within the target.
>
>Actually the Fritz-x Guided AP bomb could easily penetrate Battleship
>armor, sinking the Roma and badly damaging HMS Warspite and
>weighed in at around 3500lbs
It also caused a serious run on electric razors as well I believe :-).
Keith Willshaw
> On Tue, 10 Dec 2002 13:47:54 -0000, "Keith Willshaw"
> <keith_w...@compuserve.com> wrote:
>
> >HESH doesnt depend on KE and since HESH rounds 5% of that
> >size could kill tanks nicely it'd seem to be overkill.
>
> With a yamato sized threat it may be prudent to err on the side of
overkill
> :-). One would have also expected such a weapon to do a serious number on
> concrete fortifications etc.
>
There was a Churchill Tank modified with a petard mortar for just such
duties. Basically it fired a garbage can sized HESH charge that was
just the job for busting pillboxes. On D-Day the troops affectionately
nicknamed the flying distbin
> >The only problem is that the armor belt is often inside the hull and
below the weather deck
> >so the war head would probably explode at that level and fail
> >to penetrate the armor belt.
>
> True. Multiple HESH hits of that size exploding on deck and main gun
> turrets may have at least caused a mission kill I would have thought,
> combined with large free fall shaped charges for penetration. 3-500kg of
> copper/whatever liner as a plasma or SFF would have had serious amount of
> KE and spalling potential for causing damage deep within the target.
>
The thing is that the FAA attacks on Tirpitz basically achieved
the same thing. There's a nice write up on the web at
http://www.bismarck-class.dk/tirpitz/history/tiropertungsten.html
http://www.bismarck-class.dk/tirpitz/history/tiropergoodwood.html
Because of fusing problems many of the AP bombs didnt explode but a lot
actually penetrated the main armour deck even so the ship was so
damaged as to be practically useless
>
> >
> >Actually the Fritz-x Guided AP bomb could easily penetrate Battleship
> >armor, sinking the Roma and badly damaging HMS Warspite and
> >weighed in at around 3500lbs
>
> It also caused a serious run on electric razors as well I believe :-).
>
Keith
Tex Houston
what's a distbin?
Tex Houston(vbg)
"Keith Willshaw" <keith_w...@compuserve.com> wrote in message
news:3df61...@goliath.newsgroups.com...
Greg Hennessy
<keith_w...@compuserve.com> wrote:
>
>There was a Churchill Tank modified with a petard mortar for just such
>duties. Basically it fired a garbage can sized HESH charge that was
>just the job for busting pillboxes. On D-Day the troops affectionately
>nicknamed the flying distbin
I'd heard about that, the ancestor of todays AVREs, I believe the boffins
also developed a 7.2 inch recoilless howitzer firing a hesh round, the back
blast from that must have been truly stunning.
>
>The thing is that the FAA attacks on Tirpitz basically achieved
>the same thing. There's a nice write up on the web at
Interesting read. One can understand carriers carrying large stocks of AP
for their mounts given the likely targets they would meet.
Did land based forces island hopping in the pacific keep large stocks of
freefall AP onhand in case the yamato came round the corner though ?
Paul J. Adam
<spamc...@example.com> writes
>AFAIK, the soviets had an ASM with a seriously large shaped charge on the
>front for killing carriers. It wouldn't have been beyond the capability of
>the US in ww2 to create a free fall HEAT bomb with a meter+ wide cone and
>say 2-3000lbs of HE behind it. One of those would kill any battleship gun
>turret dead and more than likely cook off secondaries inside it putting it
>out of commission permanently.
Tallboy. Tirpitz. 'Nuff said.
(Though by then it was finishing off a cripple...)
I'd also offer ROMA in 1943, and the Fritz-X guided bomb that did the
deed.
--
Paul J. Adam
Gooneybird
George Z.
Keith Willshaw
"Tex Houston" <texho...@pcisys.net666> wrote in message
news:uvc885h...@corp.supernews.com...
> I know the British and Americans are separated by a common language but
> what's a distbin?
>
A gerbage can :)
Keith Willshaw
> On Tue, 10 Dec 2002 16:18:30 -0000, "Keith Willshaw"
> <keith_w...@compuserve.com> wrote:
>
> >
> >There was a Churchill Tank modified with a petard mortar for just such
> >duties. Basically it fired a garbage can sized HESH charge that was
> >just the job for busting pillboxes. On D-Day the troops affectionately
> >nicknamed the flying distbin
>
> I'd heard about that, the ancestor of todays AVREs, I believe the boffins
> also developed a 7.2 inch recoilless howitzer firing a hesh round, the
back
> blast from that must have been truly stunning.
>
> >
> >The thing is that the FAA attacks on Tirpitz basically achieved
> >the same thing. There's a nice write up on the web at
>
> Interesting read. One can understand carriers carrying large stocks of AP
> for their mounts given the likely targets they would meet.
>
> Did land based forces island hopping in the pacific keep large stocks of
> freefall AP onhand in case the yamato came round the corner though ?
>
The USAAF fielded the AN-Mk1 1600lb AP bomb I believe
Greg Hennessy
<ne...@jrwlynch.demon.co.uk> wrote:
>
>Tallboy. Tirpitz. 'Nuff said.
>
No argument, would have been kinda tough to hit with one it had been under
way in the open ocean though.
>I'd also offer ROMA in 1943, and the Fritz-X guided bomb that did the
>deed.
True, but just a wee bit big to be carried by the average allied fighter
bomber.
Greg Hennessy
<texho...@pcisys.net666> wrote:
>I know the British and Americans are separated by a common language but
>what's a distbin?
>
You yank chaps would call it a trash can I believe. :-)
Gordon
>I'd also offer ROMA in 1943, and the Fritz-X guided bomb that did the
>deed.
I interviewed the pilot of the Dornier that killed the Roma and he was quite a
bomber stud. Bernhard Jope says he actually hit Roma with two of them - he gave
me a photo that his gunner took at the moment of detonation and those bombs
literally blew the living shit out of that battleship. Secondaries are
rippling through the dying ship and the smoke plume is soaring thousands of
feet above it. He said 11 Do 217K-2s attacked Roma and her sister, Italia. He
launched his attack from a slant range of 6400 meters and watched the
glidebombs manuever unerringly toward their target. No problems with guidance
at all - he was jubilant to see the weapon work perfectly.
<engage thread hyper-drift>
I may be wrong, but wasn't this the first time a guided weapon had ever been
used successfully against a warship in combat?
William Wright
"Mick" <miturn...@spamoptusnet.com.au> wrote in message
news:3df4922e$0$12763$afc3...@news.optusnet.com.au...
<snip>
> Does "handed props" mean that one engine turns clockwise and the other
turns
> anti-clockwise
> Mick
>
>
No, it means in this case that one turns clockwise and one turns
COUNTER-clockwise. <insert smiley here>
Tex Houston
Tex
"Greg Hennessy" <spamc...@example.com> wrote in message
news:6efcvuk08u6fh395q...@4ax.com...
Chris Mark
fellow who flew in B-25s from the Russell Islands in the South Pacific. He
says he trained on dropping torpedos from B-25s at Eglin in mid-1943 and the
B-25Ds he flew in combat had torpedo racks installed but were never used and he
never saw any torpedo dumps. At some point an order came down to have the
racks removed.
He also mentions that he did not train in skip bombing until arriving at
Guadalcanal, where it was practiced intensively. But when they moved forward
to the Russells, they bombed from 14,000 feet. The group received 4 G models
with the 75mm gun but only flew two mission with the cannon installed. In the
first mission, at low level against port facilities, the group CO was lost,
believed shot down, and on the second mission one of the Gs blew up in mid-air
after firing one shot from the cannon. After that the 75 was pulled and
replaced by 2 .50s.
They did not fly low level missions beyond those two until re-equipped with J
models with solid noses. He notes that they were escorted by New Zealand P-40s
that stayed right on the deck with them rather than flying high cover.
He mentions a number of losses to flak, which he calls heavy and accurate and
writes of witnessing a Zero shoot down the B-25 immediately behind him (he was
tail gunner) and then without pause come after his plane. A NZ P-40 snaked in
behind the Zero and shot it down in a ball of fire, then the P-40 pulled up
beside the B-25 and he noted that the canopy was open. He saw the pilot
yelling something at them and then give a big wave and peel off---the most
beautiful sight he ever saw in his life, he says.
Chris Mark
John Keeney
Tex Houston <texho...@pcisys.net666> wrote in message
news:uvc885h...@corp.supernews.com...
> what's a distbin?
A mistyped "dustbin" I'll wager.
Bill Shatzer
On 10 Dec 2002, Gordon wrote:
> >I'd also offer ROMA in 1943, and the Fritz-X guided bomb that did the
> >deed.
> I interviewed the pilot of the Dornier that killed the Roma and he was quite a
> bomber stud.
-snips-
> I may be wrong, but wasn't this the first time a guided weapon had ever been
> used successfully against a warship in combat?
They had successful been used earlier on August 25, 1943, sinking
HMS Egret and badly damaging HCMS Athabascan.
Cheers and all,
ANDREW ROBERT BREEN
There was also the RN's U-boat-bunker-buster, which IIRC was a 18" AP
shell (ex-Furious, I suppose), rocket-assisted and carried underwing
by a USAF B17 or RAF Boeing Fortress. That would have made a nast
hole in any deck armour that could be put on anything that hoped to
float deck-uppermost.
Come to that, the 2000lb AP special bomb that the Barracuda carried was
capable of going through any deck armour in the world, provided it
hit. Wonder if it would have been possible to have got enough light
bounced back from a high-power, narrow-beam searchlight to act
as a target designator for a steered 2000lb special, or to use
visual command steering from a second aircraft? Trouble is you'd
have to use radio command in either case, but the transit time for
a dive-bomb doesn't leave much time to get ESM right.
Penetrating battleship armour wasn't a problem (2000 lb special
would do it). Hitting the battleship was, and so was getting the
fuse of the bomb to function after the hit (shaped charge would
have had an advantage here, I'll admit). Some way of upping the
hit probability of what they had would (IMO...) been a better
idea than the monster shaped charge, and maybe use of the broach
bomb most effective of all - after all, it's all about letting water
in.
Broach Bomb (or B-bomb) was a air-dropped bomb with an air chamber in it
- dropped ahead of a ship it then rose up to nestle against the bottom of
the hull before going off: a 250lb broach-bomb was reckoned to be lethal
against a cruiser and there was no way at the time of designing a ship
that would cope with that attack).
--
Andy Breen ~ Interplanetary Scintillation Research Group
http://users.aber.ac.uk/azb/
If God had intended people to program in C++
he wouldn't have invented FORTRAN (Keith Willshaw)
ANDREW ROBERT BREEN
Gordon <krzta...@aol.comint> wrote:
>>
>>I'd also offer ROMA in 1943, and the Fritz-X guided bomb that did the
>>deed.
>I may be wrong, but wasn't this the first time a guided weapon had ever been
>used successfully against a warship in combat?
No. The first successful use of a guided weapon against a warship was
a bit earlier in 1943[1], when the British sloop Egret and the Canadian
destroyer Athabaskan were attacked by Dorniers with Hs293s in the
Bay of Biscay. Athabaskan was hit and damaged, Egret took a hit which
touched off 4" ammunition and blew her side out. She turned over in
about 30 seconds, then floated for several hours upside down. Only
one survivor from below decks (the doctor, who swam out from the
sickbay). Egret had a team from the admiralty radio research establishment
on board - trying to establish what frequency was being used to
control the Hs293s and/or trying to jam them.
my father had left Egret a few months before.
[1] 27 August
Jeff Crowell
> No, it means in this case that one turns clockwise and one turns
> COUNTER-clockwise. <insert smiley here>
Engine, or just prop?
Jeff
Jeff Crowell
> I may be wrong, but wasn't this the first time a guided weapon had ever
been
> used successfully against a warship in combat?
For my money it is, but careful, Gordon... you'll reawaken
the "are torpedoes guided weapons?" thread.
Jeff
Gordon
>the "are torpedoes guided weapons?" thread.
I can only speak for the Mk. 46s -- NO, they do what they damn well please!
:)
v/r
Gordon
Bill Shatzer
> Engine, or just prop?
Both, actually. The Allison V1710s used on the P-38s came in
two flavors which rotated in opposite directions. The P-38L,
for instance, used the V1710-111 (normal rotation) and the
V1710-113 (opposite rotation).
Reportedly, one of the reasons the British insisted on deleting
the "handed" engines on the Lightning Is they ordered was to
simplify logistics and maintain full engine commonality with
the P-40 Tommahawks they had ordered.
Cheers and all,
Alan Minyard
Nope, torpedoes of various varieties were guided, and used well before
the Roma incident.
Al Minyard
Jeff Crowell
> Nope, torpedoes of various varieties were guided, and used well before
> the Roma incident.
See? See?
I hate it when I'm right.
Jeff
Jeff Crowell
> Nope, torpedoes of various varieties were guided, and used well before
> the Roma incident.
See? See?
Errol Cavit
(_yet_). What was the thread that had this 'discussion'?
Cheers
Errol Cavit
Bernie Worral
> Me-110 was meant to be. It was the only twin-engine fighter to
> take on and defeat single engine fighters, even though the P-38
> was originally developed as an interceptor to shoot down bombers.
The P-38 was sometimes dismissed by LW pilots in the ETO on this very count.
Aolf Galland made this comment after the war in an interview together with
other pilots. He considered the P-38 an easy mark, as a failed design, much
like our ME-110. I met Franz Stigler 4./JG27 a couple years ago in Dayton
and asked him what he thought of the Lockheed Lightening. He said almost
word for word what Galland said.
But something is amiss here...because the two planes aren't even comparable,
expect that they have two engines. I suppose the economic picture....that
Galland would surely think of on his strategic level...would have some other
parallels. They both were costly to produce and maintain compared to other
single engine fighters. But that is were all similarities end. In fire
power, stability, weather penetration, speed, rate of climb,
maneuverability, high altitude performance, bomb load, drag and thrust to
weight...the planes had little in common.
I still am put off by this dismissal. Of course, not all LW pilots in the
ETO said this. And even Galland had his tangles with P-38s that nearly cost
him his life.
Worr, out
Bernie Worral
> single-engined fighter."
>
> I'd say the P-38 could outfly any of its contemporaries (P-39, P-40, and
> early mark Spits and ME's). It could also hold its own against later
Spits
> and ME's, plus the FW, P-47 and P-51.
I would agree.
Most say, "Its a twin." But but don't press on to all the redeeming
qualities of the forked tailed devil.
The thing was approaching a glider in wing aspect, and thrust to weight
ratio was one of it not the highest in WWII fighter planes. It also had such
good stall characteristics it could get down and dirty without fear..unlike
the Mustang which would dip a wing very suddenly. Below 20K the 109s and FWs
were no match for it. And in the Pacific it was the most feared ac in the
USAAF arsenal.
Worr, out
ArtKramr
>From: "Bernie Worral" bwo...@nospam.cableone.net
>Date: 12/13/02 9:31 PM Pacific Standard Time
>Message-id: <uvlghl8...@corp.supernews.com>
Unfortunately we never got P-38 fighter cover. Lots of Spits and P-51's
however. The only P-38's I ever saw in the ETO were photo recon models.
Arthur Kramer
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer
Bernie Worral
> however. The only P-38's I ever saw in the ETO were photo recon models.
>
> Arthur Kramer
> Visit my WW II B-26 website at:
> http://www.coastcomp.com/artkramer
Greets, Art.
I haven't talked to you since the last great P-38 thread. When was that?
1996 or 99? I remembered you were there. ;)
Yes, there really weren't that many P-38 FGs...and what was there was tasked
to the Four Engined Bombers....not your flying cigars. ;)
20th and 55FG made an appearance in late 43. That was it! And a lonely trip
over Europe it was in a cold P-38.
Worr, out
Bernie Worral
I'm looking especially for the 38F-5; 38J-15 or 25-LO and the 38L-5
I have all the other altitudes covered.
Worr, out
Bill Shatzer
On 14 Dec 2002, ArtKramr wrote:
-snips-
> Unfortunately we never got P-38 fighter cover. Lots of Spits and P-51's
> however. The only P-38's I ever saw in the ETO were photo recon models.
Perhaps not surprising - the P-38 was beginning to be phased out of the
escort fighter role by the spring of 1944 in the ETO and by the end of the
war, only the 474th FG was still equipped with P-38s.
The P-38 was more long-lived in the fighter role in the MTO and the
Pacific and P-38s remained in use with the 8th and 9th AFs in the
fighter-bomber, bomber, and photo-recon roles right up until the end
but it was used only infrequently as an escort fighter after the first
month or two of 1944.
Cheers and all,
Gordon
>good stall characteristics it could get down and dirty without fear..unlike
>the Mustang which would dip a wing very suddenly.
Wrong, sir. Wing stall characteristics of the P-38 were awful. Maguire and
Ethell are just the first two names that pop to mind when you mention how great
the 38's stall...
Bernie Worral
Nope! :)
Ethel's father had no problems with the stall of the P-38. And you are
assuming that was what killed his son?
It was rated probably the easier aircraft to fly down aznd dirty...and much
easier than the P-51.
Marcus Fong
> Maguire and Ethell are just the first two names that pop to mind
> when you mention how great the 38's stall...
I've never read of a P-38 pilot who rated the Lightning as anything
but excellent in the stall. McGuire was performing a hard turn at
about 300' AGL, laden with external tanks, when he crashed. The
accident report from Ethell's crash indicated that he lost an engine
due to "improper fuel management" and failed to maintain minimum
single-engine speed.
Guy Alcala
> >It also had such
> >good stall characteristics it could get down and dirty without fear..unlike
> >the Mustang which would dip a wing very suddenly.
>
> Wrong, sir. Wing stall characteristics of the P-38 were awful. Maguire and
> Ethell are just the first two names that pop to mind when you mention how great
> the 38's stall...
Gordon, Maguire was killed in an accelerated stall while still carrying his
partly-full wing tanks, while he went to the aid of a wingman. Any a/c can stall,
but the P-38 gave plenty of warning, didn't suffer from torque and p-factor
effects, and was by most accounts fairly docile; the P-38's overall handling
characteristics were considered quite good. The P-51, especially the
Merlin-powered variants, had somewhat more dangerous stall characteristics and gave
considerably less warning (I'm sure Dudley can describe the stall behavior in
detail), as well as having relatively poor directional stability at high speeds in
the Merlin-engined a/c (owing to the more powerful engine and the four-bladed
prop), leading to a fair number of fuselage failures in dives, and speed
restrictions at various times during combat, unless fitted with the dorsal fin. It
also had neutral or negative longitudinal stability with more than about 1/3rd fuel
in the aft fuselage tank. Which isn't to say that the P-51 didn't have numerous
advantages of its own. IMO, the bottom line is that the P-51 was the better a/c
for the ETO escort role (more reliable engines in cold, humid conditions, better
cockpit heating prior to the P-38L), the P-38 was better in the PTO (lots of
overwater flying) and North Africa (lower altitude combat), and it's about even in
the MTO, depending on the timeframe.
Guy
Gordon
but Ethell's accident, I thought, was due to a partial power loss compounded by
his turning in toward the malfunctioning engine, and stalling in the process.
I had it in my mind that P-38s were stall prone but I can accept that I was
wrong - thanks.
v/r
Gordon
Bernie Worral
was
> wrong - thanks.
Thanks, Gordon.
The P-38 is deceptively agile. Most people have discounted it becaues its a
twin.
Worr, out
Gernot Hassenpflug
Interesting nickname I came across in the excellent book by Bruce
Gamble on the Balck Sheep: the Marines were so disgusted at the lack
of aggressiveness displayed by the Lightnings on occasion that they
dubbed them 'high-altitude foxholes'. This is the first time I had
heard of the Lightning (or rather, the pilots) being disparaged. Quite
a funny soubriquet in a decidedly unfunny environment.
I also read a book about the loss of the Sendai at the Battle of
Empress Augusta Bay, written by one of the few survivors. Very sobering...
--
G Hassenpflug RASC, Kyoto University
Guy Alcala
H'mm. Now there, I'd disagree with you, although it may just be a case of
semantics. I wouldn't describe the P-38 as agile compared to most
single-engined fighters. Agility, in my view, is the ability to change
velocity vector quickly, i.e. good pitch and roll acceleration. I couldn't
speak to the P-38's pitch capabilities, but its roll inertia was about what
you'd expect from an a/c with its engines out on the wings, not in the same
league as most singles. Once it got going its roll rate wasn't too bad,
especially with the boosted ailerons, but it still wasn't in the same league as
a P-40, FW-190, Corsair or Mustang. The P-38's strengths were more steady
state than instantaneous maneuverability. Few or no German fighters could
follow it in a turn, especially a slow speed climbing right turn with lots of
power on (no torque or p-factor to make you run out of rudder authority).
Guy
Paul Austin
"Guy Alcala" wrote ...
Interestingly, I read that the US fighter with the highest roll rate
build during WWII was...the P-61.
--
"people of means-decent folk-should be given more votes
than drifters, whores, criminals, degenerates, atheists
and indecent folks-people without means."
Paul F Austin
pfau...@bellsouth.net
Tedder
mosquito and it has a reference to the brits demo'ing the Mosquito to
Gen. Hap Arnold who then stated something along the lines ofg "we need
some of those". This lead to the US aquiring a few via reverse
lend-lease for recce work.
What confuses me about this is that given he already had P-38s for
this role, why was the Mossie "needed"? The performance of the Mossie
vs P-38 seems comparable. What was the advantage of the mosquito or
the failing of the P-38 that lead to this?
Adam S
> Below 20K the 109s and
> FWs
> were no match for it.
I would have thought that with turbosupercharged engines it should
have lots more power at high altitude? Apart from cockpit heating,
was the P-38 a bad high-altitude fighter? Surely the Me109 was
not a good high-altitude fighter except for its ability to
get there quickly.
AS
Keith Willshaw
"Tedder" <ted_l...@yahoo.com> wrote in message
news:a56b57a6.02121...@posting.google.com...
As a bomber the Mosquito has lots of payload capacity and
internal space for cameras, film and extra fuel.
Keith
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The Revolution Will Not Be Televised
<keith_w...@compuserve.com> wrote:
>> What confuses me about this is that given he already had P-38s for
>> this role, why was the Mossie "needed"? The performance of the Mossie
>> vs P-38 seems comparable. What was the advantage of the mosquito or
>> the failing of the P-38 that lead to this?
>
>As a bomber the Mosquito has lots of payload capacity and
>internal space for cameras, film and extra fuel.
Also the P-38's at the point the a few junior officers (aka James
Roosevelt) first expressed an interest in getting Mosquitos were
really badly needed as fighters: it wasn't possible to keep the two
P-38 groups initially deployed to North West Africa operational at
anything like effective strength and all the available Lightnings were
badly needed for them as a consequence.
Gavin Bailey
Unknown
>I would have thought that with turbosupercharged engines it should
>have lots more power at high altitude? Apart from cockpit heating,
>was the P-38 a bad high-altitude fighter? Surely the Me109 was
>not a good high-altitude fighter except for its ability to
>get there quickly.
>
>AS
Not to nitpick but just to clarify something in my own mind, I
always understood the naming convention to be that a supercharger
was driven from the crank and a turbocharger was driven from a
turbine in the exhaust stream, right?.
Which makes a turbosupercharger some other animal that I cannot
visualize. Am I wrong here?. Are there some blowers actually
driven by both? (at the same time).
-Gord.
Emmanuel Gustin
news:a56b57a6.02121...@posting.google.com...
> What confuses me about this is that given he already had P-38s for
> this role, why was the Mossie "needed"? The performance of the Mossie
> vs P-38 seems comparable. What was the advantage of the mosquito or
> the failing of the P-38 that lead to this?
Col. Eliot Roosevelt arrived in the UK with two squadrons of F-5s,
reconnaissance versions (in fact conversions) of P-38 fighters. These
would have had a range of about 850 miles on internal fuel, cruising
at 219 mph. This could be extended to 1750 miles at 211 mph with
external fuel tanks.
A Mosquito PR.I had a range of 2180 miles, the PR.XVI, later much
used by the USAAF, managed 2450 miles. They also cruised faster
than the F-5s, with a nominal cruising speed of 250 - 255 mph. Over
Germany, they usually flew faster than that.
F-5s had a higher top speed, especially at high altitude, but their
long-range cruising speed was inferior and their practical range
was far inferior. The Mosquito also had more room for crew and
equipment, including the rather bulky cameras. So it was logical
for Roosevelt and Arnold to want to re-equip their PR units with
Mosquitoes.
But there were never enough Mosquitoes for the USAAF, so in
early 1944 it was decided to the use them only in the ETO, with
the 8th AF, which had two Mosquito squadrons until the end of the
war.
--
Emmanuel Gustin <Emmanuel.gustin -@- skynet.be>
Military Aircraft Database, Fighter Guns Page on
http://users.skynet.be/Emmanuel.Gustin/
Larry Doering
ve...@rac.ca <"Gord Beaman"> wrote:
>Adam S <musikint...@yahoo.se> wrote:
>
>>I would have thought that with turbosupercharged engines it should
>>have lots more power at high altitude? Apart from cockpit heating,
>>was the P-38 a bad high-altitude fighter? Surely the Me109 was
>>not a good high-altitude fighter except for its ability to
>>get there quickly.
>
>always understood the naming convention to be that a supercharger
>was driven from the crank and a turbocharger was driven from a
>turbine in the exhaust stream, right?.
My understanding is that a supercharger is any device that compresses
intake air so manifold pressure can be higher than the ambient air
pressure (thereby boosting performance because you can cram more oxygen
and fuel into the engine's cylinders per firing cycle.)
A supercharger has to be driven by something. It can be a shaft or
gear arrangement from the engine, or a turbine in the engine's exhaust.
>Which makes a turbosupercharger some other animal that I cannot
>visualize. Am I wrong here?. Are there some blowers actually
>driven by both? (at the same time).
I don't think so -- I've always understood "turbosupercharger" and
"turbocharger" to be the same thing -- a supercharger powered by
a turbine that is spun by what would otherwise have been wasted
energy in the engine's exhaust stream.
ljd
Bernie Worral
> Gamble on the Balck Sheep: the Marines were so disgusted at the lack
> of aggressiveness displayed by the Lightnings on occasion that they
> dubbed them 'high-altitude foxholes'.
Hehe....I got to spend some time with Bruce and his friend Allen McCarthy
from the VMF-214.
But we even talked about this then...that the Marines knowing the Navy
Pilots and the Marines having their own pilots formed a bond that wasn't
always evident among actions worked out between the USAAF and the Marines.
Worr, out
Bernie Worral
> semantics. I wouldn't describe the P-38 as agile compared to most
> single-engined fighters. Agility, in my view, is the ability to change
> velocity vector quickly, i.e. good pitch and roll acceleration. I
couldn't
> speak to the P-38's pitch capabilities, but its roll inertia was about
what
> you'd expect from an a/c with its engines out on the wings, not in the
same
> league as most singles. Once it got going its roll rate wasn't too bad,
> especially with the boosted ailerons, but it still wasn't in the same
league as
> a P-40, FW-190, Corsair or Mustang. The P-38's strengths were more steady
> state than instantaneous maneuverability. Few or no German fighters could
> follow it in a turn, especially a slow speed climbing right turn with lots
of
> power on (no torque or p-factor to make you run out of rudder authority).
Different definitions...same word.
But the basic idea is there.....most people dismiss the 38 simply because
its a twin.
It actually had a very good roll rate at high speed.....tappered wings,
control wheel, and hydrolic boost all contributing.
It was very good down and dirty because of the gentle stall
characteristic...hence the clover leaf move was unique to this aircraft.
Yes, Jeff Ethel talks about the same move in his aritcle about the 38. The
109s couldn't follow the 38 in a spiral climb of all things!
Worr, out
Bernie Worral
> have lots more power at high altitude? Apart from cockpit heating,
> was the P-38 a bad high-altitude fighter?
It was designed as a high altitude interceptor.
But two things troubled the 38 up top....at least early on.
The first was inadequate cooling. The F-H series were all limited on power
because the intercoolers just couldn't keep up. For example the f-g series
were rated at 1325 HP up to 26,000 feet. But at 27,000 feet it was LIMITED
to 1,150 HP.
Without proper training, and maintenance, the turbos could get out of hand
up there...and sometimes even explode. The 38s in the ETO through the winter
of 43-44 had a real hard time with this.
The second was critical mach....the 38 was going so fast at 27,000 feet that
it was only nose over away from critical mach....and then the aircraft would
tuck under. This wasn't fixed til the summer of 44. hence most LW fightes
would just split ess and dive away from the 38 whenever it got the
advantage.
With the advent of the 38J-25-LO both of these problems were solved.
Worr, out
John Halliwell
<doe...@xrayspex.nlm.nih.gov> writes
>I don't think so -- I've always understood "turbosupercharger" and
>"turbocharger" to be the same thing -- a supercharger powered by
>a turbine that is spun by what would otherwise have been wasted
>energy in the engine's exhaust stream.
It's not all 'wasted energy', if you turn the exhausts backwards you get
a jet effect from the gasses, variously reported to be worth 100-150hp
from typical WWII engines.
--
John
Preston, Lancs, UK.
EndX
Larry Doering <doe...@xrayspex.nlm.nih.gov> wrote in message
news:atldub$kes$1...@lhc.nlm.nih.gov...
a turbocharger uses recycled exhaust gases to power it; a supercharger
relies on transfer of mechanical energy from the engine to drive (usually
via a belt) the turbine to compress the air for the fuel-air mix
check out http://www.enginehistory.org/OX5to3350.pdf for info
cheers,
EndX
> ljd
David Windhorst
Paul Austin wrote:
> snip
>
> Interestingly, I read that the US fighter with the highest roll rate
> build during WWII was...the P-61.
I always wondered about that. Is there any evidence -- anecdotal or
otherwise -- to back it up?
Gernot Hassenpflug
> /snipped interesting parts above this/
> But there were never enough Mosquitoes for the USAAF, so in
> early 1944 it was decided to the use them only in the ETO, with
> the 8th AF, which had two Mosquito squadrons until the end of the
> war.
A general reason to exclude Mosquitos from other theatres was because
their construction did not take well to other climates: I don't know
about the desert climate affecting them, but the humidity of the
Pacific theatre (CBI also maybe?) played havoc with the wood and glue
construction. AS far as I remember (off the top of my head) the
Australians used Mosquito FB.VIs (where I don't know, never saw any
mention of Mosquito attacks in books yet), as did the British in
Burma, but I think they considered the Beaufighter more trustworthy -
not least because of the radial engines on that plane.
ArtKramr
>From: Gernot Hassenpflug ger...@kurasc.kyoto-u.ac.jp
>Date: 12/16/02 4:28 PM Pacific Standard Time
>Message-id: <vc965tt...@kurasc.kyoto-u.ac.jp>
>
>
> general reason to exclude Mosquitos from other theatres was because
>their construction did not take well to other climates: I don't know
>about the desert climate affecting them, but the humidity of the
>Pacific theatre (CBI also maybe?) played havoc with the wood and glue
Wouldn't be hell to wake up one morning only to find that your whole squadron
had been eaten up by insects? (sheesh)
Arthur Kramer
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer
Andrew Chaplin
>
> >Subject: Re: P-38 Compared to Me-110 & Mosquito
> >From: Gernot Hassenpflug ger...@kurasc.kyoto-u.ac.jp
> >Date: 12/16/02 4:28 PM Pacific Standard Time
> >Message-id: <vc965tt...@kurasc.kyoto-u.ac.jp>
> >
> >
>
> > general reason to exclude Mosquitos from other theatres was because
> >their construction did not take well to other climates: I don't know
> >about the desert climate affecting them, but the humidity of the
> >Pacific theatre (CBI also maybe?) played havoc with the wood and glue
>
> Wouldn't be hell to wake up one morning only to find that your whole squadron
> had been eaten up by insects? (sheesh)
My grandfather was the Royal Aircraft Establishment's timber mechanics
engineer, and proved the aeronautical applicability of wood laminate
construction that De Haviland would use in the Mosquito at Princes'
Risborough in the 1930s. Born in Montréal, he was a McGill-trained
scientist and amateur cabinet maker. Where he came from the problem
had always been to get wood laminations to stay stuck together in
winter, and he would have known jack about jungles other than what he
read.
AIUI, the Aussies licked the problem with a different glue
formulation. I am not sure, but I think it also made the wood
unpalatable to most insects.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO
(If you're going to e-mail me, you'll have to get "yourfinger." out.)
Unknown
Ok...I'll buy that, so what do you (properly) call a blower
powered by the crank?. A supercharger I guess?. And I need to
pick a little at your description there. Do you think that the
turbocharger can extract power from the exhaust stream without
somehow affecting the 'motive power' of the engine?. I take
exception to your 'wasted energy' remark.
So I'll save us some time and present my case now. If you place a
turbine into the exhaust stream then you raise the exhaust
pressure that the piston must overcome to scavenge the cylinder
on the exhaust stroke, therefore extracting a horsepower penalty.
Some have argued that this turbine, if constructed properly,
merely extracts energy by using the _speed_ of the efflux,
reducing it and therefore extracting energy. (they call it a
blowdown turbine) I can't buy this either because you cannot
reduce the speed without increasing the pressure.
-Gord.
Dennis
"Larry Doering" <doe...@xrayspex.nlm.nih.gov> wrote in message
news:atldub$kes$1...@lhc.nlm.nih.gov...
Larry, the energy to drive the turbocharger does come at a cost. You cannot
get all that compression of inlet air for nothing, and the turbocharger
becomes an impediment to the exhaust airflow, resulting in increased
backpressure. This means the engine needs to make more power from the fuel
(meaning more fuel is used) in order to get the same net power at the
crankshaft, as some of the power is used in actually "pushing" the exhaust
gas out.
Think in terms of a free flow, straight through exhaust system with a car
compared to one with restrictive mufflers. Alternatively, think of the
turbocharger in place, but the turbo simply compresses the air and vents it,
with the engine seeing none of the compressed air. Still think the exhaust
is "free"?
--
--
Dennis Jensen
Author of "The Flying Pigs"
http://www.ebooks-online.com/ebooks/search.asp
NOW ONLINE
Peter Stickney
"Gord Beaman" (ve...@rac.ca) writes:
> Adam S <musikint...@yahoo.se> wrote:
>
>>I would have thought that with turbosupercharged engines it should
>>have lots more power at high altitude? Apart from cockpit heating,
>>was the P-38 a bad high-altitude fighter? Surely the Me109 was
>>not a good high-altitude fighter except for its ability to
>>get there quickly.
>>
>>AS
>
> Not to nitpick but just to clarify something in my own mind, I
> always understood the naming convention to be that a supercharger
> was driven from the crank and a turbocharger was driven from a
> turbine in the exhaust stream, right?.
Well, that's the usual usage, these days. A Supercharger, though, is
any device that increases the Inlet Manifold Pressure above the
ambient air pressure. A Turbocharger is a Supercharger that's driven
by a turbine in the exhausst stream. Geared Superchargers, like teh
ones on yer old R3350s, are mechanically driven, usually from teh
crank, but sometimes from the accessory drives. I guess some folks
like shorter names. (The Germans, for example, call 'em
Turbokompressers) It could be theat the distinctions started to be
drawn when some of the Hotrodders started playing with blowers in the
'50s.
Most WW 2 turbosupercharger installations were actually implementations
of 2 stage supercharging. (Multiple compressors in series). The
turbosupercharger stage fed, usually after passing through an
intercooler, a mechanical stage on the engine. All the U.S. setups
were like this. (B-17, B-24, B-29, P-47 and so on.) The turbo's
output was controlled by a wastegate that dumped exhaust gases past
the turbine to keep the output pressure constant until the turbine's
speed limit was reached. So, it's a variable speed blower without all
those gears & clutches, or those ugly hydraulic drives. There would
be a control somewhere near the throttle quadrant that would allow the
output level to be selected. One of the Big Deals about this is that
you don't lose Shaft Horsepower driving the Aux stage.
Now sometimes, you'll run into the term "Turbonormalize". This refers
to a turbosupercharger that's limited to put Sea Level Standard
pressure out to the engine, so that the engine sees sea level
conditions up to teh blower's critical altitude. This is used quite a
bit for aftermarket add-on kits for planes like Bonanzas & such.
In WW 2 and Postwar turbosupercharged airplanes, the usual procedure
was to balance the 2 throttles (The turbo wastgate can be considered a
Throttle, of sorts) so that the turbo was providing a slight positive
boost. This kept everything spinning & lubed & such at low altitudes.
> Which makes a turbosupercharger some other animal that I cannot
> visualize. Am I wrong here?. Are there some blowers actually
> driven by both? (at the same time).
Other than the use of a turbo as an Auxilliary stage for a 2-stage
system, I don't think it's ever been done. Pratt & Whitney did,
however, prototype an R4360 version that used both Turbosupercharging
and Turbocompounding. (Turnines in the exhaust stream geared to the
crankshaft to grab exhaust energy & put it to Shaft Horsepower. They
were expected to develop powers on the order of 4500-5000 HP at
40,000'. But they were complicated & finicky beasts, and would have
been nightmares in service. Even a stock R4360 was pushing the limits
of recip technology. (56 plugs, high lead gas, lots of fouling, 7
Magnetos. Ugh) You could shut down a perfectly happy R4360 in the
evening, and not get to start at all the next morning.
--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster
Unknown
Right...good URL here too, I have lots of experience on the
R-3350 and highly recommend this article. Thanks.
-Gord.
Peter Stickney
I've researched this for quite a while. It's not at all clear cut.
Firstly, the jet effect gives you thrust, not power. This means that
you have to consider the relationship between Power and Thrust. Power
is Thrust * Velocity, best expressed as HP=(T*V)/375. (T is lbs, V is
mph, HP is Horsepower. 1 HP = 550 ft-lbs/sec, or 375 mile-lbs/hr,
which is where dividing by 375 comes in.) Basically, that means that
at 375 mph, 1 HP = 1 lb(force) of thrust. If you're going slower than
375 mph, 1 HP is more than 1 lb of thrust, and faster, 1 hp is less.
By the same token, below 375 mph, 1 lb of thrust is less than 1 HP.
Here's a handy table, which shows the relationshtips, assuming a 1,000
HP engine with 100# of exhaust thrust. To make it easy in ourselves,
we'll assume 100% profeller efficiency, so that 1 engine HP = 1 Thrust HP.
Speed Shaft Jet Total Shaft Jet Total
HP HP THP Thrust Thrust Thrust
100 MPH 1000 27 1027 3750 100 3850
200 MPH 1000 53 1053 1875 100 1975
300 MPH 1000 80 1080 1250 100 1350
375 MPH 1000 100 1100 1000 100 1100
400 MPH 1000 107 1107 938 100 1038
450 MPH 1000 120 1120 833 100 933
As you can see, the jet thrust doesn't mean very much at low speeds.
You can also see that a propeller, being a "Constant Power" type of
system, has a big thrust advantage over the "Constant Thrust" jet.
(Which is why Me 262s, for example were so vulnerable when taking off
or landing.)
Oh, yeah, a good Rule of Thumb for potential Exhaust Thrust is that
exhaust thrust in lbs will be a bit less than 10% of engine power at
low blower critical altitude. (It's a function of Mass Flow, which
depends on displacement and RPM, and exhaust pressure, which is
related to MAP. Stuff like flame dampers & such eat into that quite a
bit)
Now that we've got that straightened out, what do we gain or lose with
a turbine-driven auxilairy supercharger vs. a mechanically driven one.
As it happens, we've got an excellent comparison using the R2800s used
in the P-47 (The Turbosupercharged R2800-21), and the F4U-1 Corsair's
R2800-8, which used a gear driven second stage. Both core engines are
pretty much the same - R2800 B series engines with a gear driven
mainstage. As far as power output is concerned, the difference is in
the supercharging.
Military Ratings
R2800-21 SL 2000 HP/2700RPM/52" MAP
27,000' 2000 HP/2700RPM/52" MAP
As you can see, the Turbo allows Sea Level Shaft HP up to tthe
Critical Altitude of the engine/supercharger combination.
R2800-8 SL 2000 HP/2700RPM/54"
2,000 2000 HP/2700RPM/52.5" Neutral (Mainstage only) Crit. Alt
16,000' 1800 HP/2700RPM/53.0" Low Aux Bower Crit Alt
21,000' 1650 HP 2700RPM/53.0" High Aux Blower Crit Alt.
As we see, in oarder to produce the same manifold conditions, and thus
Gross HP (HP before taking out the power required to drive the
supercharger), it takes 350 HP to drive the mechanical Aux stage on
the F4U. At speeds below 375 mph, you're better off from a total
power point of view, having that energy drive the propeller shaft, as
the table above shows. Above that speed, the advantage of the extra
shaft HP will diminish. braking even at a bit over 400 mph. When we
consider that very little time was actually spent going that fast, and
that the best Specific Excess Power (Which means Rate of Climb and
Sustained Turn for a WW2 fighter takes place somewhere between 150
and 250 mph TAS, depending on altitude, it's either pretty much a
wash, or an advantage for the turbosupercharged engine. (Which also
has a 6,000' advantage in critical altitude in our example.)
There's also no reason why you can't have both. The Republic F-12
(later R-12) Rainbow long range reconnaisance airplane, a late-war
design that flew just after the war, used 4 turbosupercharged R4360
engines, that delivered 3,000 HP each at 40,000'. The cooling air from
the Nacelles and the turbosupercharger outlet were directed through
jet nozzles at the rear of the nacelles, and they realized about 250#
of thrust from each nacelle. The Rainbow, BTW, could cruise at 400 mph
for 10 hours at 40,000' carrying 10,00# of payload. It eould have
been danged hard to catch.
Peter Stickney
"Gord Beaman" (ve...@rac.ca) writes:
> Ok...I'll buy that, so what do you (properly) call a blower
> powered by the crank?. A supercharger I guess?. And I need to
> pick a little at your description there. Do you think that the
> turbocharger can extract power from the exhaust stream without
> somehow affecting the 'motive power' of the engine?. I take
> exception to your 'wasted energy' remark.
>
> So I'll save us some time and present my case now. If you place a
> turbine into the exhaust stream then you raise the exhaust
> pressure that the piston must overcome to scavenge the cylinder
> on the exhaust stroke, therefore extracting a horsepower penalty.
>
> Some have argued that this turbine, if constructed properly,
> merely extracts energy by using the _speed_ of the efflux,
> reducing it and therefore extracting energy. (they call it a
> blowdown turbine) I can't buy this either because you cannot
> reduce the speed without increasing the pressure.
This is true, to a small extent, due to teh physical restriction of
teh turbine buckets in the exhaust path. However, an engine that
highly supercharged is quite "Over-Scavenged", if you will. It really
doesn't affect the breathing too much. You can even have a turbo
freeze and, other than the loss of supercharged MAP, mot notice it. I
had it happen on one of my turbocharged cars. Remember, the turbine's
extracting energy from the hot exhaust gas, which is expanding as it
comes out of the exhaust ports and exits to the atmosphere, converting
Potential Energy (Pressure & Temperature ) to Kinetic Energy (Velocity
of the exhaust gas), just like the "after-turbine" section of a jet or
turboprop. Kind of like a ball rolling downhill.
(As I remember my Thermogoddamics)
Unknown
>
>Other than the use of a turbo as an Auxilliary stage for a 2-stage
>system, I don't think it's ever been done. Pratt & Whitney did,
>however, prototype an R4360 version that used both Turbosupercharging
>and Turbocompounding. (Turnines in the exhaust stream geared to the
>crankshaft to grab exhaust energy & put it to Shaft Horsepower. They
>were expected to develop powers on the order of 4500-5000 HP at
>40,000'. But they were complicated & finicky beasts, and would have
>been nightmares in service. Even a stock R4360 was pushing the limits
>of recip technology. (56 plugs, high lead gas, lots of fouling, 7
>Magnetos. Ugh) You could shut down a perfectly happy R4360 in the
>evening, and not get to start at all the next morning.
Very interesting Peter and pretty well as I understand it too.
I'm somewhat surprised that you didn't mention the
turbocompounding of the Wright R-3350 engine though. They used
crankshaft driven superchargers and turbocompounding. Not nearly
as startling as the ones that you mention though, (2,000HP?!?)
these produce 150 BHP each at takeoff for a 450 HP per engine
increase.
They were almost trouble free too, now and then the engine would
'swallow a valve' and give them indigestion but for the most part
they worked fine.
I'm very familiar with these engines as I have over 10,000 hours
logged in Flight Engineer time on them. Damned good mill indeed.
-Gord.
Gernot Hassenpflug
> In article <blyGhHA12k$9E...@photopia.demon.co.uk>,
> John Halliwell <jo...@photopia.demon.co.uk> writes:
> > In article <atldub$kes$1...@lhc.nlm.nih.gov>, Larry Doering
> > <doe...@xrayspex.nlm.nih.gov> writes
> >>I don't think so -- I've always understood "turbosupercharger" and
> >>"turbocharger" to be the same thing -- a supercharger powered by
> >>a turbine that is spun by what would otherwise have been wasted
> >>energy in the engine's exhaust stream.
> >
> > It's not all 'wasted energy', if you turn the exhausts backwards you get
> > a jet effect from the gasses, variously reported to be worth 100-150hp
> > from typical WWII engines.
Peter, your explanation is really very helpful, thank you very much. I
could not make head of tail of several Japanese sources I read earlier
this year dealing with their attempts (mostly gear-driven) to get
supercharging to work smoothly.
> I've researched this for quite a while. It's not at all clear cut.
> Firstly, the jet effect gives you thrust, not power. This means that
> you have to consider the relationship between Power and Thrust. Power
> is Thrust * Velocity, best expressed as HP=(T*V)/375. (T is lbs, V is
> mph, HP is Horsepower. 1 HP = 550 ft-lbs/sec, or 375 mile-lbs/hr,
> which is where dividing by 375 comes in.) Basically, that means that
> at 375 mph, 1 HP = 1 lb(force) of thrust. If you're going slower than
> 375 mph, 1 HP is more than 1 lb of thrust, and faster, 1 hp is less.
> By the same token, below 375 mph, 1 lb of thrust is less than 1 HP.
>
> Here's a handy table, which shows the relationshtips, assuming a 1,000
> HP engine with 100# of exhaust thrust. To make it easy in ourselves,
> we'll assume 100% profeller efficiency, so that 1 engine HP = 1 Thrust HP.
>
> Speed Shaft Jet Total | Shaft Jet Total
> HP HP THP | Thrust Thrust Thrust
> 100 MPH 1000 27 1027 | 3750 100 3850
> 200 MPH 1000 53 1053 | 1875 100 1975
> 300 MPH 1000 80 1080 | 1250 100 1350
> 375 MPH 1000 100 1100 | 1000 100 1100
> 400 MPH 1000 107 1107 | 938 100 1038
> 450 MPH 1000 120 1120 | 833 100 933
> Military Ratings
> R2800-21 SL 2000 HP/2700RPM/52" MAP
> 27,000' 2000 HP/2700RPM/52" MAP
> As you can see, the Turbo allows Sea Level Shaft HP up to tthe
> Critical Altitude of the engine/supercharger combination.
Turbine: so what you are showing is that the shaft horsepower is kept
constant because none is required to drive the turbine (and the
turbine succeeds in keeping the manifold pressure as at
sea-level). The trade-off would then be higher fuel consumption to
maintain the output hp, i.e. to push to exhaust against the turbine ?
Does this mean that this engine can convert 2000hp to thrust, PLUS the
remaining thrust of the exhaust?
> R2800-8 SL 2000 HP/2700RPM/54"
> 2,000 2000 HP/2700RPM/52.5" Neutral (Mainstage only) Crit. Alt
> 16,000' 1800 HP/2700RPM/53.0" Low Aux Bower Crit Alt
> 21,000' 1650 HP 2700RPM/53.0" High Aux Blower Crit Alt.
Gear-driven: I am not clear on this yet, please be patient :-) So here
the output hp drops because the aux. blower takes some power (200hp)
and the main blower takes more (350hp). But the manifold pressure is
maintained as for sea-level? Hence the gross hp is kept at 2000hp, as
in the above case. However, only 1650hp at 21000ft can be converted to
thrust, PLUS all the thrust of the exhaust? The difference in
performance then depends as you said on the speed of the planes with
these two types of arrangements, as you explain below?
> As we see, in order to produce the same manifold conditions, and thus
> Gross HP (HP before taking out the power required to drive the
> supercharger), it takes 350 HP to drive the mechanical Aux stage on
> the F4U. At speeds below 375 mph, you're better off from a total
> power point of view, having that energy drive the propeller shaft, as
> the table above shows. Above that speed, the advantage of the extra
> shaft HP will diminish. braking even at a bit over 400 mph. When we
> consider that very little time was actually spent going that fast, and
> that the best Specific Excess Power (Which means Rate of Climb and
> Sustained Turn for a WW2 fighter takes place somewhere between 150
> and 250 mph TAS, depending on altitude, it's either pretty much a
> wash, or an advantage for the turbosupercharged engine. (Which also
> has a 6,000' advantage in critical altitude in our example.)
So what you are saying here is that the exhaust thrust that is
available at low speeds is far less than the equivalent hp (350) used
by the geared supercharger. Hence it is more efficient to use that
thrust to make the engine churn out more hp by using the thrust to
increase mainfold pressure? If this is correct, this makes me wonder
where is the efficiency coming from? Does the geared supercharger
always use 350hp, or does it vary from 0 at low altitude to 350 hp at
its critical altitude?
--
G Hassenpflug