From: "herzstein" Subject: COZY: constant speed propellor for 0-360 powered Cozy IV Date: Thu, 27 Jan 2000 18:50:18 -0800 I was overwhelmed with the response I received on my inquiry re electronic ignition choice by a lot of people that I respect. The consensus seems to be to go with the Jeff Rose system, but both it and the Light Speed are excellent. Not much experience with the Lasar system. Several have told me that I should use two Rose systems and forget about the magneto altogether. I'll talk this over with my partner but I am a little reluctant to put all of my eggs in one basket. Now to the subject of constant speed propeller. Nat told me that the best way to go, if I could afford it, would be with either a Hoffman or MT constant speed , due to their light weight compared to the Hartzel and others. I owned and flew a Bellanca 260B for 27 years and loved the ability of the constant speed propeller to get the most out of the engine in takeoff, climb and cruise configurations. We plan to operate out of Compton airport, which is not the largest airport in existence, and I would like full power available for takeoff with full load. It appears to me ("only my opinion, I could be wrong") that the combination of the basic 0-360 with the addition of fuel injection, electronic ignition and lightweight constant speed propeller will be optimal for the Cozy IV, remaining within Nat's configuration and not abuse his weight and CG criteria too much. Again, I'm asking for any comments and advice from anyone with experience with the Hoffman or MT constant speed propellers. Thanks again, Don Herzstein, Cozy #379 Date: Sat, 29 Jan 2000 11:04:56 -0500 From: "Marc J. Zeitlin" Subject: COZY: Non-member submission from Donald R. Bates - CS Props Donald R. Bates (not a mailing list member - he won't see replies to the list) wrote: >Don Herzstein wrote: >... >"Now to the subject of constant speed propeller. Nat told me that the >best way to go, if I could afford it, would be with either a Hoffman or >MT constant speed , due to their light weight compared to the Hartzel >and others." >............................................................................ >................................. > >Everyone: > >It's always better to use a constant speed prop on a high performance >airplane due to the wide speed range from takeoff and climb to cruise. > >We have a much better choice than Hoffman or MT here in the USA. Whirlwind >Propeller Corp (www.whirlwindpropellers.com) is growing rapidly and makes >beautiful graphite constant speed props and for a lot less than I've seen >for Hoffman and MT. Prices start for under $5000. It's owned by Jim Rust, a >young aeronautical engineer, who uses my Prop Optimizer PRO program to >design more efficient carbon blades than Hoffman or MT can get with their >wood-composite type construction. And Whirlwind props are lighter than >Hoffman or MT. > >Two years ago at the Reno National Air Races I clocked Dan Denny's Thunder >Mustang on two of its qualifying heats. One was flown with an MT prop and >the other with a McCauley Prop. The McCauley was 26 mph faster! I later >carefully measured both props. They were virtually identical in diameter, >chord and pitch distribution but the McCauley was much thinner than the MT. >Graphite is an even better material, stronger and stiffer, and so can make >thinner, more efficient and lighter blades. Whirlwind usually has a booth at >the major EAA fly-in conventions so be sure to check them out. > >Don Bates VE N151VE >Bates Engineering >www.innercite.com/~bateseng From: "Larry A. Capps" Subject: COZY: Prop Fabrication Date: Sat, 29 Jan 2000 15:07:18 -0600 To All; You made your Plane, now make that SIMPLE Prop (3-blade of course), and here's how. Nigel Field technique he used to make a composite prop from wood-fiberglass-epoxy that far exceeded the performance of commercially available props. http://members.aol.com/Lee810/propfab.html Larry Larry A. Capps Cozy MKIV #829 (chaps 4-8:) Naperville, IL capps@mediaone.net -----Original Message----- > >Everyone: > >It's always better to use a constant speed prop on a high performance >airplane due to the wide speed range from takeoff and climb to cruise. > >We have a much better choice than Hoffman or MT here in the USA. Whirlwind >Propeller Corp (www.whirlwindpropellers.com) is growing rapidly and makes >beautiful graphite constant speed props and for a lot less than I've seen >for Hoffman and MT. Prices start for under $5000. From: "Nat Puffer" Subject: COZY: Prop extensions Date: Fri, 18 Feb 2000 08:27:33 -0600 Builders, I replaced my 6 inch prop hub extension with one of Judy's 8 inch extensions. I was interested in how it affects propellor noise, engine cooling, speed, and soot on a 3-bladed prop. I don't have any hard evidence yet, but I like it. I was leary to do so for a long time, because there was an instance of an 8 inch extension failing on a Long EZ. Then someone calculated the resonance frequencies for the 6 and the 8 inch extensions, and concluded that for the 6, it was outside of the operating rpm, but for the 8 it was inside the operating rpm. The extension that failed WAS NOT made by Judy. It had machine tool marks, and did not have a smooth transition of IDs inside, like Judy's do. There has NEVER been an instance of failure of a Judy extension. That is why we suggested that everyone buy their extensions from Judy (including Ken Brock). Regards, Nat Date: Tue, 30 May 2000 21:57:34 -0500 From: David Domeier Subject: COZY: Cozy and Felix Prop I finally got all the ducks lined up today (i.e., FAA approval) and blasted off with the new Felix Bicambered 66x76 2 blade prop. It will become my backup prop as it seems a good idea to have 2 propellers if one wants to fly regularly. The numbers are preliminary first flight observations. Here's what I saw. Take off rpm was 2400. It has good "bite". The airplane feels like it wants to go. I usually climb at relatively high speed so I can see over the nose. Going through 5000 feet at 130 knots it was going up at 900 fpm. By 8000 feet the IAS was 120 knots and the rate was still around 900 fpm. At 10000 feet the IAS was 110 knots and the rate was still about 800 fpm. This was a full throttle climb and rpm's were 2630 @ 5000, 2590 @ 8000, and I forgot to write it down for 10000. If you're thinking this is a climb prop, I agree. Full throttle at 8500 yielded 179 knots TAS, the fastest flat run at 75% power I've seen in this airplane. But it was at 2830 rpm. My performance 3 blade runs at 2700 and yields about 173....once I saw 177 with it but I'm not sure that one was valid. The Felix has a "buzz" similar to the Performance but just a bit rougher. It is also beefier than the Performance in that the hub is 4.5" vrs 4.0". But weight is less. The Performance weighs 14 pounds, the Felix 12. The Felix reminds me of a Bruce Tift prop which I used on the LEZ. If anyone is interested, the Bicamber theory is explained by Fred Felix in Sport Aviation, November of '97. Some of you will want to know the cost....with Bicamber feature $835 including shipping. Without Bicamber, $120 less. There are at least 2 180 hp LEZ's flying with this prop and the owners are very satisfied. I spoke with one of them before deciding to try it. dd Date: Thu, 01 Jun 2000 20:47:51 -0500 From: David Domeier Subject: COZY: Felix Prop Finale.... After 5 hours of flight with the Felix Prop, I am signing it off as safe in accordance with FAR 91.319(b). The only thing out of the envelope is the top end rpm of 2830 at 8500 full throttle. That is not a monumental problem in my book. That's what red lines are for.....this prop is a good take off and climb prop and I am keeping it just the way it is. (today it turned 2430 for take off and then settled back to 2400 before lift off) In order to compare apples to apples in cruise, I used fuel flow vrs speed to determine if there was a serious performance problem with this propellor. There isn't. It performs very nearly as does the 3 blade from Patagonia. Example: 8500' 4gph=116TAS 5gph=125TAS 6gph=140TAS 7gph=150TAS 8gph=157TAS These are respectable numbers. If one had the patience to cruise at 5 gph, the range of the airplane would be 10 hours and 1250 NM's. At 4 gph it would be 13 hours and 1500 NM's. (nope, I'm not going to do it) Bottom line, I think this is a credible prop for the money. Nat doesn't like the 2830 and probably won't recommend it for that reason, but one could get it cut at say 66x77or78 to slow it down it that's important. One of the LEZ guys is running a 66x79 and gets 2300 on take off. He told me he would like another 100 rpm but otherwise was happy. dd Date: Sat, 03 Jun 2000 21:08:21 -0500 From: David Domeier Subject: COZY: Prop Pitch Correction Swapped props yesterday from the Felix to Performance and noticed the diameter/pitch numbers previously reported were in error....old age brain cramp at work. Felix is 66x74 Performance is 64x72 dd Date: Tue, 06 Jun 2000 21:37:52 -0500 From: David Domeier Subject: COZY: Cozy cruisin'.... Here are some numbers from a recent flight check of a new Performance 64x72 3 blade prop. Take off rpm is 2450. 75% at 8500 is 2750. I've had three Performance Props. This is the best one yet. The first one turned up 2360 on take off (and has been retired). This one developed some very small hair line cracks across the grain right where the hottest air comes out of the engine. There is no logical explanation for cracks in that area other than heat. I'd flown a couple flights with and OAT of over 100 and that probably did it. Clark Lydick loaded the prop blades to 200 pounds on the bench and did not break 'em, but we decided to retire it anyhow. The cracks were very, very tiny, but they were there and would not go away with surface sanding. The second prop turned up 2400 on take off. It was a good performer on the runway, in climb, and in cruise. Unfortunately, the #4 exhaust pipe did it in with just 7 hours total time. The third one, which Avemco paid for, Clark Lydick built on the week end of April 14 and shipped to Alabama the following Tuesday. It's pitch is a micro or two less that it's predecessor. Those of you still thinking about a prop, do consider at least 2400 rpm on take off no matter who builds it. The performance difference from 2360 to 2450 is quite noticeable. You may loose a knot or two on the top end, but who cruises above 2700? This current prop yields 165 KTAS at 12,500 at 8 gph with rpm at 2580 (at least it did yesterday) and it really gets me off the ground. I had one moment of concern on the first flight with the Performance after removing Felix. Take off and climb was very smooth and I was pleased how things were going until climbing through 5000', when a very noticeable vibration developed. Now mind you, I am very gun shy of any vibration these days and I thought what is going on now!? I pulled the power back and returned to home plate without further ado. I figured the engine might have failed internally, after all, and pulled the oil screen and filter expecting to find a ton of metal - but there was nothing. Next I went after the prop. It's balance was almost perfect and track was too. Then I got into the ignition system. I had recently installed those new Blue wires from Jeff Rose. Guess what, the #4 spiral wire insert was not making good contact with the spiral core. I put it all back together, gave her some new oil, and blasted off one more time. No more vibration. (There is a certain primal pleasure in finding a problem and fixing it....) Flying the Cozy is as good as ever. dd From: "D. Rothrock" Subject: Re: COZY: Propellers Date: Wed, 30 Aug 2000 17:01:36 -0400 Will, I 'm using a 2 Blade Sensenich 67X85 with my IO-320B1A. 160HP. Presently I'm seeing about 2320 on takeoff but I would like to get 2400 or better on takeoff. Sensenich (Steve Boser) suggests either shorten prop to 65" or have a new prop made with less pitch (67X84) will get me 50-100 more RPM. They make a nice prop at a reasonable price. Don >The prospect of actually flying my bird is getting >closer and I am seriously considering buying a prop to >push it along. Qustion is - what to buy? >3 blade or 2 blade? What pitch, what diameter? Who >make the "best" props? I have a 160HP 0-320 on the back. >I will be operating my Cozy out of Geogetown,TX where, >today, the density altitude is 3500ft! > >Your collecive experience would be appreciated! > >Will > From: "Ed Richards" Subject: COZY: Re: Propellers Date: Wed, 30 Aug 2000 22:53:52 -0400 Was asked: Qustion is - what to buy? > 3 blade or 2 blade? What pitch, what diameter? Who > make the "best" props? I have a 160HP 0-320 on the back. Will, I have the Performance 3-blade on my Mark IV as do many others and it performs great. While my Performance prop has being finished and the leading edge put on I bought a 2 blade from Ed Sterba to keep the plane flying and it's poor. I can't speak for any other brands but this Sterba prop makes the plane a real "dog" compared to the Performance. My recommendation would be to go with what others have found to work well and there sure are a lot of the 3-blade Performance props out there flying on Cozy's Ed Richards Cozy IV N826ER