Prop.

Alain1

Alain1

New member
Question:
After installing the 14-13-2 150 h.p. sensenich wooden prop showing on the TC on my 1947 165 h.p. CRUISAIR, and after trying it and with very happy result, I will have to get LSTC (limited STC).
TC call for aeromatic or other constant speed prop only for this engine. I went with my budget and my fear of complications and tendencies of wear happening or any device with moving parts. I like it simple.
Is there anybody out there that has the same installation ( I know there is one but can't find it on the net anymore!!!) and some paperwork done that could just help me showing my engineer that there is precedent?
It would help accelerate the process with our authorities.
Prop is W74RR66

Here just for info
I was cruising 160 m.p.h. at 2700 r.p.m. (Couldn,t red line at 2800!)
I was quite suprised. So at 2500 it gives me a nice high 145-148 at about 45 deg. F at 1500 feet. Airspeed confirmed with GPS.

Of course the climb is really not a rocket but acceptable. I will have to be carefull for weight on shorter field in the summer heat but I,ll see. It's way ahead of a 60 K$ cherokee and I'm happy with that.

Bellancas are the best, the hell with the rest :twisted:
 
I am jealous.... My 165hp Cruisair has the McCauley metal prop. It climbs wonderfully but 2700RPM is good for 140MPH IAS and 2600 gives 130MPH IAS. GPS seems to confirm these... I hope to do some clean-up in a few areas to improve this...
 
Well, as mention, my climb is not the greatest, I'd rather go 10 m.p.h. less but climb better. I think you're not doing bad, a good compound and wax could do a bit.
Once I had an Aero-Commander Darter. This is like poor man's 172 with mooney tail. Anyway, the darn thing wouldn't give me more then 118 m.p.h. The paint was real flat. One day, did a good compound and wax, there it was going at 125 m.p.h. . 7 m.p.h. just because of the flat finish. Most friction is on the wings and tail plane. Keep them shinning. Even with fabric. Use very fine compound not to remove too much and only if it need but use a nice good quality wax that will not seal the fabric with silicone. Silicone is not good for your finish. (I have long career in automotive and aircraft painting.)
 
Hi Guys,

What dia. & pitch are the props that you are using? I have a McCauley 74 x 60 on my 14-13-2 with a 165. It will cruise at 142 at 2600, climbs great & I can red line it (2800) at 9500 ft.

Thanks,

Ray
 
Lynn:

After reading several articles on this over the years (did a lot of reading before I got cable, alas), Alain's is a rare case. As counter-intuitive as it sounds, wax makes no speed difference in the vast majority of cases. Even Luftwaffe pilots on the channel coast during the Battle of Britain got the wax mania according to Adolf Galland, with little or no practical effect.

Having said that, much depends on the wing. Ours are semi laminar flow and, thus, are more sensitive to contamination than, say, the wings on a Cherokee. Any good hard wax will do. If the wing has a haziness or dullness beforehand it could mean that the paint has oxydized a bit, and you would do well to use a polish/wax combination product.

Basically you can go organic or synthetic. Aero Sheen, for example, is polymer based. Megulars' products employ canuba wax (I know I spelled that wrong) - an organic substance found somewhere in......Brazil or someplace. They are available at auto supply stores. The polymer polishes often boast UV protective additives. Aviation Consumer prefered Super Gloss Ultimate but they also noted that most of these polish or wax products vary only by ease of application rather than effectiveness.

Me, I like to use a polish followed by a hard canuba wax job once a year. For bugs on the leading edge during the year I use the old airmen's favorite: Lemon Pledge :)

Jonathan
 
Thanks Jon, you are so well informed. I sure hope to meet you this year and buy you a beer! Lynn N9818B :p
 
I am still wondering about the details around the props that you guys are using. Here is a copy of my prior post.

:D
 
Guess the copy didn't take here it is again.

Thanks,

Ray

Hi Guys,

What dia. & pitch are the props that you are using? I have a McCauley 74 x 60 on my 14-13-2 with a 165. It will cruise at 142 at 2600, climbs great & I can red line it (2800) at 9500 ft.

Thanks,

Ray
 
Ray,
For the speed I made, And as mentionned, I couldn't believe it but GPS... I was swinging a brand new W74RR66 sensenich wood used on the 150 h.p. when coming out of the factory and showing on the TC. Throttle against the wall.
I was alone (230 lbs) and half tanks and 45 deg. F on a nice real clear dry day at 1700 feet.
Your speed is about right. 2600 at 142 and you have good climb. I don't have a good climb. It's really a cruise prop.
If you look in the book, they claimed the 14-13-2 165 H.P.with aeromatic would cruise 160. I feel I have an aeromatic jammed in coarse pitch... :? imagine the climb? But what airplanes meet books numbers? not many.

As for the experience I had with that Aerocommander and waxing, It had a laminar flow wing similar to the Cherokee.
I had to do a study for my employer on dry wash and it's efficiency, It's been proven that on airliners and some fighter used as test platform they could save 1% of fuel. But higher you go, less friction you have due to the air getting thinner and create less friction. So not worthed anymore. I gues spending billions on fuel, 1% would be nice money.
During the second world war, there was a gang of B-17D that were ferried to Europe in one bunch. Due to short time delivery, some were left on bare aluminium and others were painted that flat dark green. For the same power setting, the bare aluminium ones were a bit faster. Is that because of the weight saving or the smoothness of the finish? I don't know.

My airline employer want to go into fuel saving. So to see if it was worthed, 4 months ago we removed the paint on a B-767 and find that there was 324 pounds of it on the fuselage only. Didn't strip the wings. And we got the fuselage polished. So I guess on B-17 you might count maybe 80 to 120 pound max including wings. By the way, the airliner decided they won't repeat the experience. Of course, it's not worthed.
But just to bring some more for discussion, During my 15 years of aircraft painter career and during the 8 years I had my own business painting aircrafts, the majority of owners of the small aluminium aircraft and fiberglass like Lancair I painted all mentionned they could get better cruise after the paint job was done. Air has viscosity and does get jammed in texture but to a certain degree. The texture of fabric does not slow down an aircraft much. The guy with the Lancair installed some turbulance tape just in the lower edge of the leading edge and gained some speed. So too glossy on some wing design will not do good.
When an aircraft with so low horse power make such a speed, it takes nothing to change a lot. Like when you go with your 10 speed bike on a flat surface with no wind. You'll go fast but just a gust or light hill and that's it. I guess a mix of good clean fairings, well rigged plane and good prop, good wax and savoir faire getting the bird on the step and keeping the ball real centered You will get quite a bit out of these ol' Cruisair for the price.
As for product I used for speed mod, I was using medium compound to bring it back and I think it was Dupont Raindance wax or Mirror Glaze MGH5 to finish but it's too long ago, I am not sure. By the way, lots of these not expensive products will be in some ''aviation' quality cans and cost an arm and a leg plus maybe an eye so shop around guys. Don't let yourself fooled by the nice picture of a Cessna Citation onthe bottle.

:roll: Alain.
 
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