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