Well well, I find these comments interesting.
First: Univair did over 50 hours of flight test on the Musketeer with the 160 hp engine. They got FAA approval for the combination. I have all the test reports, the TIA and the letter of approval. There is no mention of the prop not being compatible with the 0-320. And they did whirl test on the 0-360 180hp and that was also approved. I asked Steve, owner of Univair, why they did not go ahead with the approvals for those engines. I never got a satisfactory answer but since this was going on during the big low in airplane sales and high in law suits during the 80, I can only assume that they were spooked like a lot of other people during those law suit days.
I don't get the point, "..... so he doesn't read his own alerts". What alerts? Who's alerts. Stone throwing is so cheap. That is what is going on in the cosmology and religious arenas all over the web. And it is getting into the medical arena too, and that may not be all bad.
We make a special prop for a local Veri EZ, it is performing better than expected, cuts his takeoff by a large margin, he says it cuts him takeoff in half. My son is flying it, Veri-EZ with C-90. The propeller is smooth as silk on the EZ.
Yes it gives much the same performance that a CS prop would, don't need a governor, hollow crankshaft and weighs about half that of a metal CS prop and it doesn't dome apart on the back of an EZ like metal props do. The prop, in fully automatic version, looses about 20 rpm per thousand feet of altitude. If you use high altitude airports you can make a small change in counterweights to gain back the rpm at higher altitudes. So you can make you adjustments to suit the conditions. I have designed a version for pilot control and I also have designed a CS version. Neither of which need governor or hollow crank. I was targeting the certified market for them but the Federal Anti Aviation Administration doesn't like me or the damn prop. Theat is typical of someone who doesn't understand something, they want to get rid of it.
Anyhow, I am changing my target customers from certified planes to EAB airplanes.
BTW. In case you are interested, in the 70 years the prop has been available for the certified market there have been only three AD note against it.
One is the tipping. The leading edge metal has relief cuts about every 5". These relief cuts did not go around the leading edge. The outer 5 inches would come off sometimes because of the tip flexing near Mach one. So the AD note cut the relief cut to go all around the leading edge from bottom to the top.
Another AD put a rpm restriction on the 165hp Stinson 108. There was a vibration above 2650rpm. The AD not only applied to the Stinson and not the Bellanca that used the same engine. So after the AD came out further research was done on the Stinson. They found that there was a small design flaw in the hub. There was an interference a high pitch angles. So they wrote AD note. After the AD came out they found and fixed the interference problem by making a mod to one of the parts. This fixed the problem but it didn't fix the AD note problem. I presented the whole story to LA ACO and asked them to remove the AD note. I got some crap that AD notes live forever, you can't kill them. Our FAAA at work on our nickel.
The other AD note requires the removal, to one side, of the balance band around the barrel and inspect for cracks. There was one crack found in a prop back in the 40s or 50. They wrote an AD note. Turns our that the snap-ring-groove that receives the snap ring that holds the blade in the hub, had a faulty machining in it. So they wrote an AD note. But when they found out the problem they never went back to kill the eternal AD note. There has never been another hub found with the faulty machining. I tried to get LA ACO to remove that one too but when the FAA hears something they don't like they clam up and become verbally constipated. And if thye got you on their Cada LIsto, the whole office goes into hibernation, instead for the cold season, it last for years and years. Oh, and so does our FSDO and MIDO.
Another little note of interest, maybe. I made two props for the EZ. The first one I used an existing blade design that came with the engineering that Koppers did during WW-II and later for civil aircraft. Those airplane were in the 60 to 130 mph speed range. The fastest plane they designed for was the Bellanca and maybe the Johnson Rocket.
There is something that I am not even sure the big boys know about. That has to do with not only the pitch but also the amount of twist in the blade. When you start getting up toward the 200 mph, actually in the 150 mph rang, you have to, for best efficiency, design more twist in each blade. I don't plan to go into the math and talk about Archimedes Screw here but it is important.
And here is another little tid-bit of data. You may have heard that Hartzell came out a few years ago bragging about their new "Blended Airfoil" propellers. Well well, every propeller blade, at least in the last 75 or more years, has a blended airfoil. If it didn't the efficiency would be so poor that you could outrun your airplane on foot.
Another
