Adjustable Prop for a Cessna 150
Charles Talleyrand
propeller suitable for a an o-200 engine.
I understand that putting this prop on my C-150 is illegal. But
suppose ...
Suppose I put this prop on my Cessna 150. It only weighs 9.5 pounds,
as compared to the Sensenich weight of 24 pounds. So I save 14.5
pounds.
Can anyone guess how this would effect my performance? How much
better climb and how much better cruise?
-Just curious
See http://www.ivoprop.com/inflightultralightmodel.htm
And http://www2.sensenich.com/misc/c150.htm
Vaughn Simon
"Charles Talleyrand" <kitpl...@gmail.com> wrote in message
news:3f5451f1-6105-45b5...@r66g2000hsg.googlegroups.com...
>Suppose I put this prop on my Cessna 150. It only weighs 9.5 pounds,
>as compared to the Sensenich weight of 24 pounds. So I save 14.5 #.
But it will make a largish change in your CG. The fuel and passenger load
for a 150 are both near the CG, so you might end up putting a few pounds of
ballast in the tail to stay within the CG envelope. That would cost you some of
the initial weight advantage.
>Can anyone guess how this would effect my performance? How much
>better climb and how much better cruise?
Nobody can answer that question until you specify a pitch. Any given fixed
pitch prop will be optimized for climb (at the expense of cruise speed) or
cruise (at the expense of takeoff and climb performance) or somewhere in
between.
--
Vaughn
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Nothing personal, but if you are posting through Google Groups I may not receive
your message. Google refuses to control the flood of spam messages originating
in their system, so on any given day I may or may not have Google blocked. Try
a real NNTP server & news reader program and you will never go back. All you
need is access to an NNTP server (AKA "news server") and a news reader program.
You probably already have a news reader program in your computer (Hint: Outlook
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http://news.aioe.org/ for free and/or http://www.teranews.com/ for a one-time
$3.95 setup fee.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Will poofread for food.
Mark Hansen
> "Charles Talleyrand" <kitpl...@gmail.com> wrote in message
> news:3f5451f1-6105-45b5...@r66g2000hsg.googlegroups.com...
>
>
>>Suppose I put this prop on my Cessna 150. It only weighs 9.5 pounds,
>>as compared to the Sensenich weight of 24 pounds. So I save 14.5 #.
>
> But it will make a largish change in your CG. The fuel and passenger load
> for a 150 are both near the CG, so you might end up putting a few pounds of
> ballast in the tail to stay within the CG envelope. That would cost you some of
> the initial weight advantage.
If you reduce the weight of the prop, won't that move your CG aft?
Requiring less weight in the tail (actually, anywhere behind the CG) to
support the same flight envelope?
>
>>Can anyone guess how this would effect my performance? How much
>>better climb and how much better cruise?
>
> Nobody can answer that question until you specify a pitch. Any given fixed
> pitch prop will be optimized for climb (at the expense of cruise speed) or
> cruise (at the expense of takeoff and climb performance) or somewhere in
> between.
>
>
>
--
Mark Hansen, PP-ASEL, Instrument Airplane, USUA Ultralight Pilot
Cal Aggie Flying Farmers
Sacramento, CA
Charles Talleyrand
wrote:
> "Charles Talleyrand" <kitplan...@gmail.com> wrote in message
>
> news:3f5451f1-6105-45b5...@r66g2000hsg.googlegroups.com...
>
> >Suppose I put this prop on my Cessna 150. It only weighs 9.5 pounds,
> >as compared to the Sensenich weight of 24 pounds. So I save 14.5 #.
>
> But it will make a largish change in your CG. The fuel and passenger load
> for a 150 are both near the CG, so you might end up putting a few pounds of
> ballast in the tail to stay within the CG envelope. That would cost you some of
> the initial weight advantage.
>
> >Can anyone guess how this would effect my performance? How much
> >better climb and how much better cruise?
>
> Nobody can answer that question until you specify a pitch. Any given fixed
> pitch prop will be optimized for climb (at the expense of cruise speed) or
> cruise (at the expense of takeoff and climb performance) or somewhere in
> between.
Actually, one can assume that it will climb at least as well as the
standard climb prop, and cruise at least as well as the standard
cruise prop.
The difference between the cruise (normal) prop climb performance, and
the climb prop climb performance, will be available to cruise prop
users.
The difference between the climb prop cruise performance, and the
cruise prop cruise performance, will be available to climb prop users.
Anyone know these numbers?
Alternatively, there must be planes that have used both fixed and
constant-speed props. Anyone know the difference?
Jim Logajan
> Alternatively, there must be planes that have used both fixed and
> constant-speed props. Anyone know the difference?
Don't know about the Cessna 150, but I'm pretty sure some owners of
experimentals (such as the RV series) have tried both fixed and later
constant speed props on the same engine and airframe. If interested, I
suspect one could find numbers mentioned on the forums on this web site:
http://www.vansairforce.net/
benf...@aol.com
> On 08/15/08 12:10, Vaughn Simon wrote:
>
Mark is dead right on this one,,, And you might end up with an ill
handling plane with an aft CG that will happen.....
be safe out there.
Vaughn Simon
"Mark Hansen" <m...@NOSPAMwinfirst.com> wrote in message
news:75-dnVTY0bwXRTjV...@posted.surewest...
>
> If you reduce the weight of the prop, won't that move your CG aft?
> Requiring less weight in the tail (actually, anywhere behind the CG) to
> support the same flight envelope?
>
Brain fart! Yes, you are 100% correct.
We would need to saw off tail structure to fix the CG. (just kidding)
Worst case, you would need to add weight as far forward as possible, and that
added weight would have to be MORE than the weight that you saved by swapping
the prop because it would necessarily need to be mounted closer to the CG than
where the weight came off (the prop).
Just to add a bit of noise to the discussion, an airplane operating at
maximum allowed aft CG is actually more aerodynamically efficient. Sailplane
pilots often add tail ballast for just this reason.
BT
BT
"Vaughn Simon" <vaughnsimo...@att.FAKE.net> wrote in message
news:Owkpk.3624$Mh5....@bgtnsc04-news.ops.worldnet.att.net...
BT
to be tail heavy
BT
"Charles Talleyrand" <kitpl...@gmail.com> wrote in message
news:5fe908d9-1e10-4c92...@34g2000hsh.googlegroups.com...
BT
the CG at the 85% point was the most efficient..
too far aft was too much and caused nose down stick putting the elevator
down into the slip stream, and not far enough aft caused back stick or up
elevator into the slip stream.
Heavier pilots do add tail ballast which increases the minimum pilot weight
for club gliders.
BT
Dan_Thom...@yahoo.com
> Don't forget the CG change.. losing 14# on the nose is a lot.. you are going
> to be tail heavy
> BT
>
Can always make a spinner out of lead:-)
I don't like Ivo. We had one on a Glastar and couldn't balance
the thing because the blades wouldn't stop shifting chordwise in the
hub. And that was on a redrive, not the more brutal direct-drive
applications. They're not that efficient, either, since the pitch
change is mostly outboard on the blades. There have been some issues
with blades leaving the hub or the torque rods pulling right out of
the blades. Those blades are a high-density foam with only the
thinnest skin of carbon fiber on them, and the bolt bushings are
therefore held in mostly by foam. Not for me. We put a Warp Drive on
the airplane and it was much smoother, though adjusting the pitch was
much more work.
A Cessna 150 isn't likely to gain a lot of performance from an
adjustable prop. The airframe is too draggy and the engine too
anemic.
Dan
Ricky
> I notice that there are Ivoprop makes an in flight adjustable
> propeller suitable for a an o-200 engine.
>
> I understand that putting this prop on my C-150 is illegal. But
> suppose ...
If Ivoprop makes an adjustable prop for the O-200 it seems there would
be an STC for a conversion. Is there not?
!50s & 152s have so many STCs available.
Ricky
Dan_Thom...@yahoo.com
IVO isn't a certified propeller, and you can't get an STC to
install an uncertified prop. Until it's certified there won't be any
STC. IVO and Warp Drive and a bunch of other props are aimed
exclusively at the kitplane, homebuilt and unltralight market.
Dan
Stealth Pilot
for the 150...
48" pitch climb
50" pitch normal
52" pitch cruise
look at it this way. your aircraft will be the only cessna in
existence with a solid lead spinner to get the cg right. :-)
Stealth pilot
Kyle Boatright
"Jim Logajan" <Jam...@Lugoj.com> wrote in message
news:Xns9AFB9E6D9D01...@216.168.3.30...
As an RV builder/owner I 've seen that discusion a hundred times. I
selected a fixed pitch prop with a cruise pitch for my airplane. My
airplane cruises as fast and efficiently as any 160 HP RV-6 you'll find,
regardless of fixed pitch or constant speed prop. However, my airplane's
acceleration and climb performance is far inferior to RV's with constant
speed prop's.
In my airplane, the takeoff run is made at full throttle, which delivers
about 2200 RPM and 29" of MP. That's probably 75% power or less. The
constant speed guys are turning 2700 RPM and are also showing 29" of MP.
They are getting 100% power. That extra 40 ponies makes a huge difference
until I get my airplane closer to its ideal speed regime, which is 140+
knots and allows the engine to turn up to 2500+ RPM. In level flight with a
wide open throttle and at 1000 MSL on a standard day, the engine will spin
my prop to slightly over 2700 RPM, which pulls the airplane along at 175+
knots...
KB