Prop advice for Lycoming 0235

[chad@midlanddisplay.com]

Been using the two blade sensenich for three years and would like more cruise performance. The sensenich is fine, but I want to bolt on a prop
that gives me more speed. Take off distance is not a concern, getting there is. Any one tell me what to get, and what to expect for my Series Five O235 L2C with a better prop? Ground adjustable is fine as I may not be able to afford IFA.

thanks Guys! (and Gals)

[Moses]

Try Craig @ craig@Cattoprops.com. Ph 2097543553. I have used his props on three different kits.. I am putting an O235 in my SS7 and am awaiting the prop for this project. Need more info call me @ 386-405-7404 . Larrie

[PapuaPilot]

Ditto on the Catto prop. I plan to get one for my IO-240 soon. A friend of mine with a Super Cub says he got better takeoff and cruise performance with a Catto prop.

[n85ae]

My airplane could probably have fifty different props on it, and it's gonna
go 120 no matter what I use, I have the power to hit 140+ in level flight
if I push the go knob. However 120 is the magic number for cruise, and I
think this is where the drag really builds up fast, as anything faster eats
power. Props do not seem to affect it and I have tried several.

The only real thing I notice with prop changes is takeoff and climb changes.
I currently run a fairly flat 74" Sensenich which gets me 2300 static rpm.
This gets me a fast takeoff and a nice climb. Around 2000 fpm on a nice
cold day when low fuel, and there's lot's of Cessna's in the pattern

This is on a Series 5 with IO-240B

Regards,
Jeff

Been using the two blade sensenich for three years and would like more cruise performance. The sensenich is fine, but I want to bolt on a prop
that gives me more speed. Take off distance is not a concern, getting there is. Any one tell me what to get, and what to expect for my Series Five O235 L2C with a better prop? Ground adjustable is fine as I may not be able to afford IFA.

thanks Guys! (and Gals)

[Esser]

Hi Jeff,

do you think you could clean up anything to get past 120? Fair the jury struts etc?

[n85ae]

I have faired my struts, etc. already so I'm in fact not seeking to solve any
speed problems, I view the aerodynamic footprint of the plane as being the
problem for cruise speed. Which will in fact make prop changes for cruise -
Relatively insignificant.

I'm trying to emphasize that the drag of the plane begins increasing
exponentially around 120 ... So the fact is (to me) that prop changes will
affect takeoff and climb, BUT there is an aerodynamic wall for this plane at
around 120, which if I want to go faster - I need fundamentally an
entirely different airplane.

No matter how much you tweak the prop you end up with relatively minute
differences in thrust at cruise perhaps a few percent, whereas at around
120 drag is jumping 10, 20, 40, 80% for each few mph beyond that.

So while tweaking the prop a lot might help a little, it will not overcome the
aircraft's poor aerodynamics which causes drag to increase a lot beyond a
certain speed range.

Same reason on my CH-801 I'm not planning to take off the Slats like a lot
of guys are doing. Jeez if I want speed - I'd be building a Falco ...

Regards,
Jeff

[n85ae]

Also in my plane I can hit VNE (140) in level flight without difficulty, BUT it takes
a lot more power beyond 120 to do it. If I want to listen to the engine roar like
mad, and watch the fuel consumption fall through the floor. Yep knob against
the panel, and max rental power will do it. Nevertheless 120 is the end of
happiness with the plane speedwise. It does not like going faster.

Regards,
Jeff