Silent Super Efficient Propeller!
Leviterande
Hi all!
Volf propeller here:
http://www.rexresearch.com/volfprop/volfprop.htm
I have been thinking alot about how this propeller would do, I wish I
had a workshop, CNC, and tools to build one.. this amazing prop is
claimed to be super quiet and efficient.. so any more info from the
article on it or any word of experience in propellers are very
appreciated
what about this propeller
( hit CTRl-F and type "An Air Screw That Ridicules Propeller" )
http://www.rexresearch.com/aero/1aero.htm
regards
kalle
--
Leviterande
Kingfish
306a...@aviationbanter.com> wrote:
> Hi all!
> Volf propeller here:http://www.rexresearch.com/volfprop/volfprop.htm
>
> I have been thinking alot about how this propeller would do, I wish I
> had a workshop, CNC, and tools to build one.. this amazing prop is
> claimed to be super quiet and efficient.. so any more info from the
> article on it or any word of experience in propellers are very
> appreciated
>
Looks like a ducted fan to me. Judging from the pictures, it's
doubtful CFD existed when the patent was approved and modern rotor
design would probably be more efficient. Technology progresses, ya
know?
a
> Volf propeller here:http://www.rexresearch.com/volfprop/volfprop.htm
>
> I have been thinking alot about how this propeller would do, I wish I
> had a workshop, CNC, and tools to build one.. this amazing prop is
> claimed to be super quiet and efficient.. so any more info from the
> article on it or any word of experience in propellers are very
> appreciated
>
> what about this propeller
>
> regards
> kalle
>
> --
> Leviterande
That's a very old patent! If you think about a propeller for low speed
flight, think about it as a rotating wing. You'll notice high
perfornance gliders have long slender wings, and the best props look a
lot like that, with an additional twist. Ducting helps, as do Q tips
on propeller edges, but I did read somewhere you gain as much
efficiency by increasing the propeller diameter as the q tip length.
Makes me wonder if the vortex decreasing terminations on wings might
be as well used just by increasing the wingspan by that amount.
Dan_Thom...@yahoo.com
> That's a very old patent! If you think about a propeller for low speed
> flight, think about it as a rotating wing. You'll notice high
> perfornance gliders have long slender wings, and the best props look a
> lot like that, with an additional twist. Ducting helps, as do Q tips
> on propeller edges, but I did read somewhere you gain as much
> efficiency by increasing the propeller diameter as the q tip length.
> Makes me wonder if the vortex decreasing terminations on wings might
> be as well used just by increasing the wingspan by that amount.
That's exactly what Steve Wittman found 25(?) years ago on his Buick-
powered tailwind. He stuck some winglets on it, got some improvement,
then laid them down horizontally and found that they worked just as
well that way.
Dan
Gezellig
wrote:
So is the vertical winglet
1) To increase wing length while
2) Looking cute
?
Martin X. Moleski, SJ
>So is the vertical winglet
>1) To increase wing length while
>2) Looking cute
... and to make it easier to clear obstacles when taxiing
in crowded airports?
Marty
--
Big-8 newsgroups: humanities.*, misc.*, news.*, rec.*, sci.*, soc.*, talk.*
See http://www.big-8.org for info on how to add or remove newsgroups.
a
wrote:
> On Fri, 5 Sep 2008 12:42:38 -0400, Gezellig <nokon...@gmail.com> wrote in <6id5ruFq3i9...@mid.individual.net>:
>
> >So is the vertical winglet
> >1) To increase wing length while
> >2) Looking cute
>
> ... and to make it easier to clear obstacles when taxiing
> in crowded airports?
>
> Marty
> --
> Big-8 newsgroups: humanities.*, misc.*, news.*, rec.*, sci.*, soc.*, talk.*
Don't forget it makes it easier to parallel park too.
Leviterande
'a[_3_ Wrote:
> ;659074']On Sep 5, 1:10 am, Leviterande Leviterande.
> 306a...@aviationbanter.com wrote:-
> Hi all!
> Volf propeller hehttp://www.rexresearch.com/volfprop/volfprop.htm
>
> I have been thinking alot about how this propeller would do, I wish I
> had a workshop, CNC, and tools to build one.. this amazing prop is
> claimed to be super quiet and efficient.. so any more info from the
> article on it or any word of experience in propellers are very
> appreciated
>
> what about this propeller
> ( hit CTRl-F and type "An Air Screw That Ridicules Propeller"
> )http://www.rexresearch.com/aero/1aero.htm
>
> regards
> kalle
>
> --
>
> That's a very old patent! If you think about a propeller for low speed
> flight, think about it as a rotating wing. You'll notice high
> perfornance gliders have long slender wings, and the best props look a
> lot like that, with an additional twist. Ducting helps, as do Q tips
> on propeller edges, but I did read somewhere you gain as much
> efficiency by increasing the propeller diameter as the q tip length.
> Makes me wonder if the vortex decreasing terminations on wings might
> be as well used just by increasing the wingspan by that amount.
so your guess is that none of the props are more efficient then todays
propellers? the todays propellers didnt differ from the ones used 100
years ago btw...
Kalle
--
Leviterande
a
Oh? Constant speed props are that old? On a more serious note, today's
props are part of an aerodynamic systems and better engineered. Would
you care to cite a reference supporting your claim tha efficiencies
have not improved? Other than one you write yourself, of course.
Jim Logajan
> On Sep 5, 12:02 pm, Leviterande <Leviterande.
> 3074...@aviationbanter.com> wrote:
>> the todays propellers didnt differ from the ones used 100
>> years ago btw...
>
> Would you care to cite a reference supporting your claim tha efficiencies
> have not improved?
Barging in...
I don't know about 100 years ago, but many airship propeller efficiencies
were measured at over 65% efficient in 1920s. The reference I have is Table
13 from "Airship Design" by Charles P. Burgess (1927) [Still in print,
btw.] While there are some low "outliers" under 50% efficient, the bulk of
the 26 table entries show propeller efficiences between 55% and 65%. These
were prop efficiences at maximum speed and horsepower.
The airships LZ-120, LZ-121, Bodensee, and Nordstern appear to have had the
highest efficient props at 66%.
For more recent props, according to these sources:
http://en.wikipedia.org/wiki/Propeller
http://www.epi-eng.com/propeller_technology/selecting_a_propeller.htm
current props peak around 87% efficient under optimum conditions.
If the average efficiency in the 1920s was ~60% and now is ~85% then that
is a an improvement of ~45%. On the other hand, no one will ever be able to
double on the efficiencies they were already getting over 80 years ago. ;-)
a
> a <papp...@gmail.com> wrote:
> > On Sep 5, 12:02 pm, Leviterande <Leviterande.
> > 3074...@aviationbanter.com> wrote:
> >> the todays propellers didnt differ from the ones used 100
> >> years ago btw...
>
> [...]
> > Would you care to cite a reference supporting your claim tha efficiencies
> > have not improved?
>
> Barging in...
>
> I don't know about 100 years ago, but many airship propeller efficiencies
> were measured at over 65% efficient in 1920s. The reference I have is Table
> 13 from "Airship Design" by Charles P. Burgess (1927) [Still in print,
> btw.] While there are some low "outliers" under 50% efficient, the bulk of
> the 26 table entries show propeller efficiences between 55% and 65%. These
> were prop efficiences at maximum speed and horsepower.
>
> The airships LZ-120, LZ-121, Bodensee, and Nordstern appear to have had the
> highest efficient props at 66%.
>
> For more recent props, according to these sources:
>
>
> current props peak around 87% efficient under optimum conditions.
>
> If the average efficiency in the 1920s was ~60% and now is ~85% then that
> is a an improvement of ~45%. On the other hand, no one will ever be able to
> double on the efficiencies they were already getting over 80 years ago. ;-)
Yeah, it'll take some magic to convert rotary power into throwing air
backwards hard enough to improve efficiency very much, at least for ga
airplanes. A big fluted duct to take advantage of ram air induction
might help, but any back of the envelope sketches doesn't show much
room for other things, like pilots, and hauling around ducts adds
weight too. I'm not expecting to see many breakthroughs, but if they
are coming we'll probably see it in a home built at Oshkosh one of
these years.
Dan_Thom...@yahoo.com
> So is the vertical winglet
>
> 1) To increase wing length while
> 2) Looking cute
>
> ?
3) Is sometimes used as a marketing tool, I think, like fins on
cars in the late '50s and '60s.
Winglets improve efficiency by controlling wingtip vortices. A
vortex represents lost energy or drag, whichever way you want to see
it, and if the airflow that forms the vortex can be directed in some
way that minimizes the loss, then winglets are worth it. Some winglets
are claimed to convert some of the reclaimed energy into thrust. Burt
Rutan could speak to that one.
Laying it down would have the effect of making the wingtip very
small, of short chord, and such tips make smaller vortices. Famously
fast and efficient airplanes have often used sharply tapered wings;
think Spitfire or DeHavilland DH88 Comet. Or Google those images.
Leviterande
Now woludnt a shorter prop with a bigger chord(and q-tips) move more air
and thus creating equal thrust as a longer propeller with thinner chord?
when I tried the patented fan it was pretty quiet however.
'a[_3_ Wrote:
> ;659137']On Sep 5, 1:21 pm, "Martin X. Moleski, SJ"
> mole...@canisius.edu
> wrote:-
>
>
>
> On Fri, 5 Sep 2008 12:42:38 -0400, Gezellig nokon...@gmail.com wrote
> in 6id5ruFq3i9...@mid.individual.net:
> -
> So is the vertical winglet
> 1) To increase wing length while
> 2) Looking cute-
>
> ... and to make it easier to clear obstacles when taxiing
> in crowded airports?
>
> Marty
>
> --
> Big-8 newsgroups: humanities.*, misc.*, news.*, rec.*, sci.*, soc.*,
> talk..*
> Seehttp://www.big-8.orgfor info on how to add or remove newsgroups.-
>
> Don't forget it makes it easier to parallel park too.
--
Leviterande
a
307a...@aviationbanter.com> wrote:
> Now woludnt a shorter prop with a bigger chord(and q-tips) move more air
> and thus creating equal thrust as a longer propeller with thinner chord?
>
> when I tried the patented fan it was pretty quiet however.
>
AS for longer chords? Probably not. Think of the most efficient wings
for airplanes -- the ones that provide the best lift/drag. They are
long and slender. The same principles hold for props. You can be sure
if wide chords were better they'd be showing up on experimental
aircraft, and they are not.
Gezellig
Unknown
<Leviteran...@aviationbanter.com> wrote:
>
>Now woludnt a shorter prop with a bigger chord(and q-tips) move more air
>and thus creating equal thrust as a longer propeller with thinner chord?
>
>
>when I tried the patented fan it was pretty quiet however.
>
>********************************************************************
How about thrust????
Big John
********************************************************************
Bertie the Bunyip
@x35g2000hsb.googlegroups.com:
They do actually, and they can be very efficient indeed.
http://www.youtube.com/watch?v=Nxz1UF67EQI
There's also been the Dyke Delta, and the facetmobile, of course.
Bertie
Leviterande
does anybody have a good pic of a Q-tip propeller?
it seems hard to find any.. hartzell props are known but didnt find any
pic..
the propelller efficiences have improved without doubt but what i am
sayin is that particulary fan might be differnt.. we just have to try
it out
--
Leviterande
a
> a <papp...@gmail.com> wrote in news:e5fb9dcd-6bd8-42e3-9a50-f6370d188424
I don't think you'd find these as 'efficient' as conventionally shaped
aircraft, else we'd be seeing competition gliders shaped this way.
Those airplane shapes would have very light wing loading of course,
but huge wetted areas -- think drag.
. As for using that concept for prop blade shape, , where efficiency
is defined in the conventional engineering sense as power out divided
by power in, long and thin blades seem to win over short and fat.
Bertie the Bunyip
news:14d9aabc-33a9-4fdf...@79g2000hsk.googlegroups.com:
Yeah, I understand al of that, but the word efficient is one that is
often bandied as some sort of standard, but is just as misunderstood.
While I know you mean aerodynamic efficiency in it's purest form, the
mission is the yardstick by which you must measure the success of an
airplane. Gliders are good at what they do, but they're as much a
compromise as any other type of airplane. Low aspect ration machines
have a few enormous advantages, not the least of which is a huge speed
range and relatively low drag at low alpha. Span loading is more
relevant than area loading in many ways and application, depending on
what you're trying to get the wing to do at any given momen, and a low
span loading, as in a glider, has to be paid for with drag just like
any other aerodynamic benifit. Simply put, the longer the span, the more
air you're moving around. Now, for some applications, this is more
efficient, since by agitating a greater volume air in a less agressive
fashion than a little air, you may, and may is the operative word here,
create less drag in your flight situation.
> . As for using that concept for prop blade shape, , where efficiency
> is defined in the conventional engineering sense as power out divided
> by power in, long and thin blades seem to win over short and fat.
Depends on the application and what you're asking the blade to do.
Length brings its own problem here again, but in spades, since tip
speeds, particulalry at high cruise speeds, becomes a problem.
There simply are no pat answers in aerodynamics. "Monoplanes are more
efficient than biplanes" for instnace, is an oft touted example. Simply
not true in every aspect. It depends on what you're asking the airplane
to do. Of course, particualrexamples may be plucked from the air to
prove almost any POV here. You could look at two types of aircraft and
compare their performance with a single yardstick, such as fuel burn,
but that doesn't make one more efficient than another as whole. just on
fuel burn. If the fuel efficient one can't get out of the 800 foot strip
it's parked in and the other one can, then the one that can is the more
efficient machine for it's mission. That's not to say some airplanes
aren't just plain inefficient, but it is a bit ridiculous to say that
just because there's a popular mission and most airplanes tend to gel in
that corner of design that those types of aircraft are ultimatley the
most efficient things in the sky.
Bertie
a
The mission that seems best served by short span broad chord
propellers seems to be in the marinas -- long and thin are not popular
there. Even that may be changing, you may have seen a satellite view
of an Ohio class submarine with its screw exposed recently (the navy
goofed, those things are usually shrouded when they would be otherwise
exposed) and it looked like something that belonged on an airplane.
See
Martin X. Moleski, SJ
<Leviteran...@aviationbanter.com>:
>does anybody have a good pic of a Q-tip propeller?
This might be one:
http://www.princeaircraft.com/PhotoGallery.aspx?id=83
>it seems hard to find any...
Agreed!
Here's a good one. You can zoom in on the picture and
see the Q-tips quite clearly:
Marty
--
Big-8 newsgroups: humanities.*, misc.*, news.*, rec.*, sci.*, soc.*, talk.*
See http://www.big-8.org for info on how to add or remove newsgroups.
Lonnie
"Bertie the Bunyip" <T...@ld.you> wrote in message
news:Xns9B116CC775A...@208.90.168.18...
Power/mercy snip ->
> Bertie
>
What a load of bullshit.
Efficiency is directly related to mission profile. That's not a spin, is
frigging verbal lomcevak.
If I didn't know better, I would suspect Anthony was forging your post.
Lonnie
"Bertie the Bunyip" <T...@ld.you> wrote in message
>
>
> They do actually, and they can be very efficient indeed.
>
>
> http://www.youtube.com/watch?v=Nxz1UF67EQI
>
> There's also been the Dyke Delta, and the facetmobile, of course.
>
>
>
> Bertie
>
Why would the Buttlipps be promoting the flying HEEL?
Professional courtesy?
Kindred spirit?
Name association?
Leviterande
Bertie, yes sad all available science arnt known nor popular among
people, circular wing and flying wings that are chord thick proved to
be alot better then just rektangular slender wings, the stall speed is
very very low, the weight strength ratio is awsome .. etc..
the model of the propeller I made was alot quiter then normal
propellers.. but it was way out of balance and so i didnt get thrust
enough.. I just made it with foam)depron)
--
Leviterande
jeremy
>> Bertie
>
> The mission that seems best served by short span broad chord
> propellers seems to be in the marinas -- long and thin are not popular
> there. Even that may be changing, you may have seen a satellite view
> of an Ohio class submarine with its screw exposed recently (the navy
> goofed, those things are usually shrouded when they would be otherwise
> exposed) and it looked like something that belonged on an airplane.
>
> See
>
> http://www.armscontrolwonk.com/1626/secret-screws
>
Old news and that screw design is less for thrust and more for cavitation free
operation, although the byproduct is quite high speeds for extremely low
rotation rates.
JJ
a
I'm really interested in how you determined those noise
characteristics with a prop made of structural foam. Did you have an
internal structure for strength? And as for noise, were you comparing
it to a conventional prop made the same way? I'd like to know how to
model some things like this myself, would rather learn from someone
else's experience than have to reinvent something.
Leviterande
Actually in teh begining of the last century many designers started
building circular aircraft, and all teh reports indicated that the
flying saucer had advantages as :
easy and slow to fly
almost impossible to stall
highly crash proof
cheap easy to manufacter
if you dont think that is efficieny then I dont know what it is
i read also in leonard G cramps books that during early wing tunnel
tests
the standard wing were ""retricted to be tested with very limited
AOA"" unlike the circular wings taht have been tested in extreme angles
of attack without stall!!
well, it is been a little offtopic but lets take a look at this
propeller I found and it is patented 2008
it is easy to contruct too
what do you think?
http://www.freepatentsonline.com/7396208.html
http://www.linkgrinder.com/Patents/Divided_blade_r_7396208.html
'Lonnie[_3_ Wrote:
> ;659369']"Bertie the Bunyip" T...@ld.you wrote in message
> news:Xns9B115A1626D40****upro...@208.90.168.18...-
>
>
> They do actually, and they can be very efficient indeed.
>
>
> http://www.youtube.com/watch?v=Nxz1UF67EQI
>
> There's also been the Dyke Delta, and the facetmobile, of course.
>
>
>
> Bertie
> -
>
> Why would the Buttlipps be promoting the flying HEEL?
>
> Professional courtesy?
> Kindred spirit?
> Name association?
--
Leviterande
a
3089...@aviationbanter.com> wrote:
> Actually in teh begining of the last century many designers started
> building circular aircraft, and all teh reports indicated that the
> flying saucer had advantages as :
>
> easy and slow to fly
>
> almost impossible to stall
>
> highly crash proof
>
> cheap easy to manufacter
>
> if you dont think that is efficieny then I dont know what it is
>
> i read also in leonard G cramps books that during early wing tunnel
> tests
> the standard wing were ""retricted to be tested with very limited
> AOA"" unlike the circular wings taht have been tested in extreme angles
> of attack without stall!!
>
> well, it is been a little offtopic but lets take a look at this
> propeller I found and it is patented 2008
>
> it is easy to contruct too
>
> what do you think?
>
>
> 'Lonnie[_3_ Wrote:
>
>
>
> > ;659369']"Bertie the Bunyip" T...@ld.you wrote in message
> >news:Xns9B115A1626D40****upro...@208.90.168.18...-
>
> > They do actually, and they can be very efficient indeed.
>
> >http://www.youtube.com/watch?v=Nxz1UF67EQI
>
> > There's also been the Dyke Delta, and the facetmobile, of course.
>
> > Bertie
> > -
>
> > Why would the Buttlipps be promoting the flying HEEL?
>
> > Professional courtesy?
> > Kindred spirit?
> > Name association?
>
> --
> Leviterande
"Efficiency" in the sense I am using it is in the conventional
engineering terms -- power out divided by power in. For every
horsepower you deliver to the prop shaft under given conditions there
some work -- force times distance -- returned. It's perfectly fine to
use different definitions, but let the reader know what the definition
is.
I've the sense one can get even higher than the 75 to 80 percent good
ones deliver these days, but the 'overhead' in ducts and the like make
those systems not quite realizable: that is, practical, for general
aviation. Be interesting to see what happens..
Bertie the Bunyip
news:3bdcc9b5-67cc-4c34...@z72g2000hsb.googlegroups.com:
> On Sep 6, 5:41 am, Bertie the Bunyip <T...@ld.you> wrote:
>> a <papp...@gmail.com> wrote
>> innews:14d9aabc-33a9-4fdf-9ca5-78e407249a02@7
Well, my main drive has short span long chord blades. So do most high
bypass fan jets...
Bertie
Bertie the Bunyip
>
> "Bertie the Bunyip" <T...@ld.you> wrote in message
> news:Xns9B116CC775A...@208.90.168.18...
>
> Power/mercy snip ->
>
>> Bertie
>>
>
> What a load of bullshit.
Nope.
>
> Efficiency is directly related to mission profile. That's not a spin,
is
> frigging verbal lomcevak.
>
> If I didn't know better, I would suspect Anthony was forging your
post.
>
Of course you would. Since you're an idiot, you couldn't understand any
of it. Since you're an idiot, you can't differenatiate between someone
who has a pretty good idea of what he's talking about and a not-even-
wannabe.
it's just who you are.
Be proud, k00k.
Bertie
Bertie the Bunyip
Nope, thoght you must be quite familiar with their properties from being
stepped on.
Bertie
Bertie the Bunyip
news:17ada50d-f994-4ea3...@x41g2000hsb.googlegroups.com:
to do what? Travel a distance? Make a top speed? Rate of climb?
That's the point I was making. I was alos using the smae yardstick, just
not for one particualr mission, and high aspect ratio wings do not
deliver in every case.
Bertie
>
>
Bertie the Bunyip
news:Leviteran...@aviationbanter.com:
You are truly a wonder.
Bertie
Unknown
Unknown
<Leviteran...@aviationbanter.com> wrote:
>
>Actually in teh begining of the last century many designers started
>building circular aircraft, and all teh reports indicated that the
>flying saucer had advantages as :
>
>easy and slow to fly
>
>almost impossible to stall
>
>highly crash proof
>
>cheap easy to manufacter
>
>if you dont think that is efficieny then I dont know what it is
>
>i read also in leonard G cramps books that during early wing tunnel
>tests
>the standard wing were ""retricted to be tested with very limited
>AOA"" unlike the circular wings taht have been tested in extreme angles
>of attack without stall!!
>
>***********************************************************
Leviterande
I built and tested some circular aircraft. At positive AOA they were
very stable and with extreme AOA just picked up a high sink rate still
under control.
However, as they approached a zero AOA, they started to lose stability
and with no warning would tuck and all control was lost.
As a result of these tests, my SIL decided not to construct that type
of GA bird as it would be a death trap.
Big John
a
early on I mentioned relatively low speed GA airplanes, and for sure
recognize the difference fan jets provide. I'm sure you recognize that
the high bypass stuff you drive is a different animal, and really not
unlike the ducted fan with lots of hardware overhead I also
mentioned.
Get thy tongue from thy cheek! Your digression was from Anthony's
manual.
Bertie the Bunyip
news:b2735259-d892-4737...@59g2000hsb.googlegroups.com:
> On Sep 6, 5:24 pm, Bertie the Bunyip <T...@ld.you> wrote:
>> a <papp...@gmail.com> wrote
>> innews:3bdcc9b5-67cc-4c34-a7a2-41e2a744b82d@z
Not really. In fact I wondered if you might be an anthony sock for a
bit!
I just have a bee in my bonnet about emprical statements!
You're not wrong about high aspect ration wings, but you're not
completely right either. You're not going to win a soaring competition
with an airplane with a 1-1 aspect ratio doesn't mean youcan't make it
do something quite respectable.
That Arup had some remarkable performance figures. They were far from
just being a curiosity in the thirties when they were built. They got a
lot of attention in the aviation press and the performance was
remarkable. I have some of them somewhere but just going from memory the
small engined ones, I think it had a 75 HP LeBlond on it, had a speed
range of something like 30-120 MPH. They have some serious drag issues
at low speeds, of course, but this can be turned to advantage, giving a
steep approach so desirable in stol ops.
This is the reason the Navy were interested in the Flying Flapjack
airplanes in the mid 40s. Potentially good carrier airplanes with a very
high cruise speed.
Bertie
a
If you associate me with Mx your judgment is seriously impaired. Keep
an eye on that, and if the manifestations continue seek some
professional help before it's too late.
I seriously doubt the form factors those airplanes suggest for props
would lead to any improvement in propeller efficiency, using the
classical (energy out over energy in) definition. If they did,
hanging one on a C152, C172, or a P140 would improve things like rate
of climb or service ceiling or fuel economy (my Mooney gets about 18
mpg) by about the the same percentage as increased efficiency. There
would be a nice market for such an improvement. My prediction is we'll
continue to see only narrow chord blades in front of us for the next
15 years.
Leviterande
Hi everybody, I just really wish I could view your intersting replies
without the very very long "quotes" that come automaticly.. so could
you please just delete the unnessesary quotos ?
any way.. the efficiency right now for me is the developed "static
thrust" per horsepower" helicopter are good at but their complicated
cyclcic and collective mechanincs and the very huge rotors takes down
the efficiency( my opinion only) so what i am simply looking for is a
simple propeller that is shafted to a motor (with or without gears)
that is not too large for its thrust..
q-tips propellers are coming closer to that and that is why the fan I
made with side portions was quite compared to other conventional rc
propellers
did you check this?:
http://www.linkgrinder.com/Patents/Divided_blade_r_7396208.html
it is new and simple propeller claimed to produce 200 pounds of
static thrust at a 85cm diamter with a 30hp!
as i said I would appreciate if we could talk about efficieny of
propellers
thanx
Kalle
--
Leviterande
a
it is new and simple propeller claimed to produce 200 pounds of
> static thrust at a 85cm diamter with a 30hp!
Thrust has nothing to do with efficiency. If the engine weighed 200
pounds it develops 200 pounds of thrust downward just sitting there.
Horsepower measures work, in common units that would be about moving
33000 pounds a foot every minute (I may be wrong about that number).
You told us the work going in -- that's 30 hp. What is the work coming
out?
Maybe you should define your problem or issue differently. It now
seems to be you're trying to do something with an RC model. What
exactly is your objective? Tell us that, and you'll have a better
chance at getting a useful answer.
My understanding is that RC models have power to burn -- way more than
scale -- but my knowledge of that world is very limited.
Y
Lonnie
"Bertie the Bunyip" <T...@ld.you> wrote in message
>
>
> to do what? Travel a distance? Make a top speed? Rate of climb?
>
>
> That's the point I was making. I was alos using the smae yardstick, just
> not for one particualr mission, and high aspect ratio wings do not
> deliver in every case.
>
>
> Bertie
Bullshit, you are just trolling and trying to drift the thread. Get lost
lamer.
Lonnie
"Bertie the Bunyip" <T...@ld.you> wrote in message
>
> You are truly a wonder.
>
>
>
> Bertie
Maybe to you, buy you seem to wonder about a lot of things.
Lonnie
"Bertie the Bunyip" <A...@AA.AA> wrote in message
news:g9usij$c5i$1...@blackhelicopter.databasix.com...
>
> Of course you would. Since you're an idiot, you couldn't understand any
> of it. Since you're an idiot, you can't differenatiate between someone
> who has a pretty good idea of what he's talking about and a not-even-
> wannabe.
>
>
> it's just who you are.
>
>
> Be proud, k00k.
>
>
>
>
>
> Bertie
Nonsense Kaptain Klueless, I know exactly that you are nothing but a wanna
be troll.
Lonnie
"Bertie the Bunyip" <T...@ld.you> wrote in message
news:Xns9B12554895...@208.90.168.18...
Bullshit. You tripped on your wanker on your first post (probably drunk
again) and have been stumbling to rationalize it ever since.
Sounds just like Anthony.
Leviterande
I am into vtol craft and thats why i am into the most efficient not
so huge propellers, i pilot rc models and am currently testing
several designs
the propellers is the most important part of a vtol
engine ofcourse has to be light but todays engines are superb in that
aspect
'Lonnie[_3_ Wrote:
> ;659583']"Bertie the Bunyip" A...@AA.AA wrote in message
> news:g9usij$c5i$1...@blackhelicopter.databasix.com...-
>
> Of course you would. Since you're an idiot, you couldn't understand
> any
> of it. Since you're an idiot, you can't differenatiate between
> someone
> who has a pretty good idea of what he's talking about and a not-even-
> wannabe.
>
>
> it's just who you are.
>
>
> Be proud, k00k.
>
>
>
>
>
> Bertie-
>
> Nonsense Kaptain Klueless, I know exactly that you are nothing but a
> wanna
> be troll.
--
Leviterande
Lonnie
"Leviterande" <Leviteran...@aviationbanter.com> wrote in message
news:Leviteran...@aviationbanter.com...
>
> I am into vtol craft and thats why i am into the most efficient not
> so huge propellers, i pilot rc models and am currently testing
> several designs
>
> the propellers is the most important part of a vtol
>
>
> engine ofcourse has to be light but todays engines are superb in that
> aspect
>
Have you reviewed the propeller and rotor types currently flying on state of
the art VTOL aircraft?
Morgans
"Leviterande" <Leviteran...@aviationbanter.com> wrote
> I am into vtol craft and thats why i am into the most efficient not
> so huge propellers, i pilot rc models and am currently testing
> several designs
>
> the propellers is the most important part of a vtol
>
>
> engine ofcourse has to be light but todays engines are superb in that
> aspect
I put this to you.
If you look at the latest VTOL series of rotorcraft, since the basic
helicopter design, you will find the answers you seek.
Hint: they don't have screw shaped rotors, for their lift producing
devices.
The Osprey has main rotors about halfway between helicopters of that weight
and prop planes of that weight. Very roughly.
Don't you think they would use the most efficient, smallest, lightest form
of prop that could be invented to do the job?
Hint: The answer is yes.
--
Jim in NC
Leviterande
yes, I have been looking into todays vtols, they either have a
complicated large merry go arround rotor system or a very very
highly concentrated plumes of air as in the harrier/F35 jet
both are very expensive to maintain, complicated and yet not so
practical unless in military.
so some kind of a propeller/ fan/ rotor with no moving part must do
the job somehow to get rid with the complexiity and cost and SPACE!
I was just thinking of testing a thick-chord fan with 4 blades and
a medium AOA. it should be geard to the motor unless the motor has a
very high torque. My idea is that efficiency should go up when one use
a geared system
example:
my model vtol/thrust test rig weights around 700grams and teh
thrust is around 880g, the power from the electric motor is around
166w
the propeller is a standard slowfly 10x4,7
rpm is around 7000-8000
if we instead took a 7 inch impeller with larger blades moving more
air at one revoltuion , i tmeans it makes more drag and resistance
to the motor shaft.. now if one calculate the required data and put
reduction gear to the motor. the thrust out put should be equal at less
rpm and smaller propeller and with the same efficiency!
I could be way wrong but that is just what i think could be possible
--
Leviterande
a
I have seen battery powered conventional shaped RC models accelerate
upward vertically. while spinning what seemed like unremarkable props,
so they clearly had thrust exceeding weight. I'm trying to understand
the problem you're trying to solve. Has it to do with using a smaller
engine for a given airframe?
Bertie the Bunyip
news:432fd301-870f-4c68...@i76g2000hsf.googlegroups.com:
> On Sep 7, 3:23 am, Bertie the Bunyip <T...@ld.you> wrote:
>> a <papp...@gmail.com> wrote
>> innews:b2735259-d892-4737-b243-0514e9cd3f84@5
Nah, just suspicious.
>
> I seriously doubt the form factors those airplanes suggest for props
> would lead to any improvement in propeller efficiency, using the
> classical (energy out over energy in) definition. If they did,
> hanging one on a C152, C172, or a P140 would improve things like rate
> of climb or service ceiling or fuel economy (my Mooney gets about 18
> mpg) by about the the same percentage as increased efficiency. There
> would be a nice market for such an improvement. My prediction is we'll
> continue to see only narrow chord blades in front of us for the next
> 15 years.
Oh i don't see any change. Toothpicks have, by far, been the most common
props on lightplanes for years and not without good reason. I'm not
arguing that. But it depends on a lot of things. A lot of turboprops
have relatively wide chord scimitar props, for instance. My point was
really more directed towards the sentiment that efficiency shoud be
described in such narrow terms. Most people want an airplane to go from
A-B real fast and burn as little fuel as possible, but that doesn't mean
that it's nore efficient than an airplane that excelles in some other
way..
Bertie
Bertie the Bunyip
>
> Hi everybody, I just really wish I could view your intersting replies
> without the very very long "quotes" that come automaticly.. so could
> you please just delete the unnessesary quotos ?
Not a fucking chance.
Bertie
>
>
>
Bertie the Bunyip
Nope. You're just laming, period.
Fjukkktard.
Bertie
Bertie the Bunyip
Yes, I do.
Bertie
Bertie the Bunyip
Nonsense. I'm an excellent troll.
Bertie
Bertie the Bunyip
Real helpful google boi.
Bertie
Bertie the Bunyip
Nope.
Don;t you think you're being a bit hard on yourself calling yourself a
wanker, though?
Oh wait, you don't know what one is because you're a fjukktard.
>
> Sounds just like Anthony.
Yeh, right.
Bertie
Unknown
> Leviterande wrote
>it is new and simple propeller claimed to produce 200 pounds of
>> static thrust at a 85cm diamter with a 30hp!
>
>Thrust has nothing to do with efficiency. If the engine weighed 200
>pounds it develops 200 pounds of thrust downward just sitting there.
>
>Horsepower measures work, in common units that would be about moving
>33000 pounds a foot every minute (I may be wrong about that number).
>You told us the work going in -- that's 30 hp. What is the work coming
>out?
>
>Maybe you should define your problem or issue differently. It now
>seems to be you're trying to do something with an RC model. What
>exactly is your objective? Tell us that, and you'll have a better
>chance at getting a useful answer.
>
>My understanding is that RC models have power to burn -- way more than
>scale -- but my knowledge of that world is very limited.
>
Your 100% correct.
I have built a number of model aircraft with unlimited vertical
performance.
One I sat on it's tail in a cardboard box and took off vertically out
of box to the impress my straight and level flying friends.
Big John
Dan_Thom...@yahoo.com
30ae...@aviationbanter.com> wrote:
> yes, I have been looking into todays vtols, they either have a
> complicated large merry go arround rotor system or a very very
> highly concentrated plumes of air as in the harrier/F35 jet
>
> both are very expensive to maintain, complicated and yet not so
> practical unless in military.
>
> so some kind of a propeller/ fan/ rotor with no moving part must do
> the job somehow to get rid with the complexiity and cost and SPACE!
>
> I was just thinking of testing a thick-chord fan with 4 blades and
> a medium AOA. it should be geard to the motor unless the motor has a
> very high torque. My idea is that efficiency should go up when one use
> a geared system
> the propeller is a standard slowfly 10x4,7
> rpm is around 7000-8000
> if we instead took a 7 inch impeller with larger blades moving more
> air at one revoltuion , i tmeans it makes more drag and resistance
> to the motor shaft.. now if one calculate the required data and put
> reduction gear to the motor. the thrust out put should be equal at less
> rpm and smaller propeller and with the same efficiency!
Helicopters and other VTOLs are complicated because they have to
be. One of the things that bugged the early experimenters was
gyroscopic force; any time we change the plane of rotation of a prop
or rotor we get precession, which results in a loss of control unless
the system is designed to deal with it. A fixed-pitch rotor can't do
that, and the larger it is and faster it turns the worse the effects
of precession. Current helicopter designs all take advantage of
precession to tilt the rotor disc, applying blade lift at 90 degrees
ahead of the desired blade rise.
The other factor is the necessity of being able to glide. No
fixed-pitch rotor is going to do that (unless it's an autogyro, with
an undriven rotor and very low pitch angles) and even some sink could
cause blade stall and loss of control.
Do the research. Find out, the easy way, whcy others couldn't
make work. Google "Moller," for instance.
Dan
Lonnie
"Bertie the Bunyip" <A...@AA.AA> wrote in message
>
> Nonsense. I'm an excellent troll.
>
>
> Bertie
BULLSHIT!!!!!
You're lamer than a ruptured duck.
a
Because models are so overpowered compared with full size, could some
of those problems be solved with air blowing over controllable fins? A
smaller diameter prop would get a lot of velocity across the fins, and
that could be used to offset rotation and could tilt the axis for
translation. It might take a little computer power, or maybe just a
skilled pilot, for easy control.
It would have to be a labor of love, I doubt there's a DOD or
commercial use for such a device.
Lonnie
"Bertie the Bunyip" <T...@ld.you> wrote in message
news:Xns9B13D5C2385...@208.90.168.18...
>
> Oh i don't see any change. Toothpicks have, by far, been the most common
> props on lightplanes for years and not without good reason. I'm not
> arguing that. But it depends on a lot of things. A lot of turboprops
> have relatively wide chord scimitar props, for instance. My point was
> really more directed towards the sentiment that efficiency shoud be
> described in such narrow terms. Most people want an airplane to go from
> A-B real fast and burn as little fuel as possible, but that doesn't mean
> that it's nore efficient than an airplane that excelles in some other
> way..
>
>
>
> Bertie
And all your input has had zip shit to do with "Silent Super Efficient
Propellers".
Quit rattling your empty head. You're starting to sound like Anthony again.
Bertie the Bunyip
Actually, it does.
>
> Quit rattling your empty head. You're starting to sound like Anthony
> again.
Yeh, right wannabe boi..
Bertie
Bertie the Bunyip
Yeh, sure wannabe boi.
Bertie
david hillstrom
wrote:
heres a story for you airplane heads from an electrical engineer.
i used to work for Black & Decker years ago. and once we did an
experiment with a certain tool for marketing. one tool had the normal
not so efficient fan in it, and the other had a super quiet high
efficiency fan in it that actually allowed about 25% more runtime off
the battery, including a bit more power.
we took them out into the field for user comparison. ~every~ ~single~
~person~ we did the comparison with thought the louder, less efficient
tool was more powerful BECAUSE OF THE NOISE. even though they were
dead wrong, thats what they thought, and thats how they bought their
tools.
my 2 cents
a
> On Tue, 9 Sep 2008 09:58:48 +0000 (UTC), Bertie the Bunyip <A...@AA.AA>
> wrote:
>
>
>
Harley bikers demonstrate that too. Now, if we could make a Cub sound
like a jst. . .
Peter J Ross
hillstrom <da...@meow.org> wrote:
If you build a LOUD version of Usenet, they will come.
--
PJR :-)
slrn newsreader (v0.9.9): http://slrn.sourceforge.net/
extra slrn documentation: http://slrn-doc.sourceforge.net/
newsgroup name validator: http://pjr.lasnobberia.net/usenet/validator
jeremy
> Harley bikers demonstrate that too. Now, if we could make a Cub sound
> like a jst. . .
Cross posts removed.
Other than the noise, having to get off the thing and wheel it around corners
should be some indication of a problem with the fundamental design :-)
JJ
Leviterande
Hi David, that sounds very intersting and that was my thought from the
begining , the more silent a machine is the more effective it really
is, coul you give more info about that fan?
Kalle
heres a story for you airplane heads from an electrical engineer.
i used to work for Black & Decker years ago. and once we did an
experiment with a certain tool for marketing. one tool had the normal
not so efficient fan in it, and the other had a super quiet high
efficiency fan in it that actually allowed about 25% more runtime off
the battery, including a bit more power.
we took them out into the field for user comparison. ~every~ ~single~
~person~ we did the comparison with thought the louder, less efficient
tool was more powerful BECAUSE OF THE NOISE. even though they were
dead wrong, thats what they thought, and thats how they bought their
tools.
my 2 cents
--
Leviterande