Adjustable Prop for a Cessna 150

On Aug 15, 8:08 pm, "BT" wrote:
Don't forget the CG change.. losing 14# on the nose is a lot.. you are going
to be tail heavy
BT

"Charles Talleyrand" wrote in message

...

On Aug 15, 3:10 pm, "Vaughn Simon"
wrote:
"Charles Talleyrand" wrote in message

...

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?

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

On Aug 15, 1:46*pm, Charles Talleyrand wrote:

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

On Aug 15, 11:41 pm, Ricky wrote:
On Aug 15, 1:46 pm, Charles Talleyrand wrote:

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

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

On Fri, 15 Aug 2008 14:35:38 -0700 (PDT), Charles Talleyrand
wrote:

On Aug 15, 3:10 pm, "Vaughn Simon"
wrote:
"Charles Talleyrand" wrote in message

...

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?

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

"Jim Logajan" wrote in message
.. .
Charles Talleyrand wrote:
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/

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