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#1
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Metal Prop vs. Wood Prop
I have a wood prop on my Taylorcraft and the GPS says it's slow, at around
65 kts. How about a discussion on the relative merits of wood and aluminum props. I understand that wood is easier on your engine but the aluminum prop is more efficient. Another thing I notice too, especially on the O-320 and O-360-powered RV's is that the wood prop is so light it has little flywheel effect and if you don't have your timing retarded, it will kick back in a heartbeat. I figure the wood prop on a Van's aircraft is for CG. I think what I'll do is buy an aluminum prop and try it for a while. I couldn't keep up with a DCO-75 last week and it was a little embarrassing, since his engine was sick. But he had an aluminum prop. |
#2
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On Sat, 20 Sep 2003 19:21:22 -0400, "Larry Smith"
wrote: I have a wood prop on my Taylorcraft and the GPS says it's slow, at around 65 kts. How about a discussion on the relative merits of wood and aluminum props. I understand that wood is easier on your engine but the aluminum prop is more efficient. Another thing I notice too, especially on the O-320 and O-360-powered RV's is that the wood prop is so light it has little flywheel effect and if you don't have your timing retarded, it will kick back in a heartbeat. I figure the wood prop on a Van's aircraft is for CG. To retard the timing because of a wooden prop is nuts. I've never met anyone dumb enough to even consider this. YMMV. FWIW.... My 0-320 with wooden prop would attempt to shake the airframe and itself apart below 900 rpm. So, you accept the 900 rpm idle. That's it. Period. With metal prop -- Idle is acceptably smoooth, even at 650 rpm. Added bonuses - brake life is increased. No longer does the RV3 with 79 pitch attempt to taxi at 20+ mph. Running in rain is a joy. No varnish to be damaged - unlike with wood. I think what I'll do is buy an aluminum prop and try it for a while. I couldn't keep up with a DCO-75 last week and it was a little embarrassing, since his engine was sick. But he had an aluminum prop. Sorry, there's more here than meets the casual eye. A friend has two 65 hp T-Crafts with McCauley 45 pitch props. Both run 90 mph at 2150 rpm. Both will exceed 100 mph at WOT at 2000 ASL. P.S. Unless you look real close... A metal prop pitched the same as a wood one will cruise about the same. Not worth the money difference in speed, if that is all you're looking for. If you have to go significantly faster... remove the wings or at least clip them and bolt on a C-85. Barnyard BOb -- |
#3
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"Barnyard BOb --" wrote in message ... On Sat, 20 Sep 2003 19:21:22 -0400, "Larry Smith" wrote: I have a wood prop on my Taylorcraft and the GPS says it's slow, at around 65 kts. How about a discussion on the relative merits of wood and aluminum props. I understand that wood is easier on your engine but the aluminum prop is more efficient. Another thing I notice too, especially on the O-320 and O-360-powered RV's is that the wood prop is so light it has little flywheel effect and if you don't have your timing retarded, it will kick back in a heartbeat. I figure the wood prop on a Van's aircraft is for CG. To retard the timing because of a wooden prop is nuts. I've never met anyone dumb enough to even consider this. YMMV. No flywheel effect with the lightweight prop. Add to that one of those hot-spark electronic ignitions and you have the engine's flywheel and the starter trying to tear each other up. Kickback. Never had it happen to me but have seen it, so you are supposed to retard the timing, but just at starting time, by starting on the mag, NOT on the Electroair. After she begins running then you turn on the Electroair and everything is running at advanced timing. And btw I recall reading that Klaus Savier (Lightspeed) would advance his timing from the cockpit to as much as 45 degrees before top dead center. During a race. At altitude. But not when starting. ymmav. FWIW.... My 0-320 with wooden prop would attempt to shake the airframe and itself apart below 900 rpm. So, you accept the 900 rpm idle. That's it. Period. With metal prop -- Idle is acceptably smoooth, even at 650 rpm. Added bonuses - brake life is increased. No longer does the RV3 with 79 pitch attempt to taxi at 20+ mph. Running in rain is a joy. No varnish to be damaged - unlike with wood. I think what I'll do is buy an aluminum prop and try it for a while. I couldn't keep up with a DCO-75 last week and it was a little embarrassing, since his engine was sick. But he had an aluminum prop. Sorry, there's more here than meets the casual eye. Yeah, and a sick engine will still run like a scalded dog. We had a 210-horse Continental once with compressions in the 30's and that thing was a running piece of plunder. A friend has two 65 hp T-Crafts Selfish. He should share. with McCauley 45 pitch props. Both run 90 mph at 2150 rpm. Both will exceed 100 mph at WOT at 2000 ASL. I want that. Must try to achieve it. It may be necessary to do a little rigging and clean things up a little. Your friend probably has his faired in a little better than mine, wheel pants, that sort of thing, to make it slicker, and you can take some of the twist out of the wings too. Makes them squirrelly but faster. One benefit, though, is that if you take out all the wash-out it doesn't turn to wash-in when you're flying inverted. P.S. Unless you look real close... A metal prop pitched the same as a wood one will cruise about the same. Not worth the money difference in speed, if that is all you're looking for. If you have to go significantly faster... remove the wings Like those turkey buzzards and redtails hereabouts which fold theirs up and drop like bottle rockets when the Pud and I chase them? or at least clip them and bolt on a C-85. That's an idea. Maybe another T-Craft like your friend. I already have the C-85. It needs a top but the bottom is sound. I called Sensenich about an aloonium* prop and they want 2600 bucks for one. So I'll look for a used one. Our clipwing expert in this neck of the woods, down in Mebane, builds his wings with lightweight ply ribs and uses a hopped up O-200. I think he calls it a Swick. Barnyard BOb -- *Aside: This one should really get him hopping. |
#4
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"Larry Smith" wrote: I called Sensenich about an aloonium* prop and they want 2600 bucks for one. So I'll look for a used one. *Aside: This one should really get him hopping. ++++++++++++++++++++++++++++++ Careful... or I won't save you any money on a Sensenich prop. You should be able to buy NEW for around $1800.... but not directly from Sensenich. They only give 10% discounts, AFAIK. You wanna talk nice now and do a little HOPPING for me? I have a dealer source that discounts Sensenich. If you talk real nice I might even arrange a Sensenich T-shirt for your smart ass. Barnyard BOb -- a very satisfied Sensenich customer |
#5
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"Barnyard BOb --" wrote in message ... "Larry Smith" wrote: I called Sensenich about an aloonium* prop and they want 2600 bucks for one. So I'll look for a used one. *Aside: This one should really get him hopping. ++++++++++++++++++++++++++++++ Careful... or I won't save you any money on a Sensenich prop. O, I'm in milquetoast mode from now on. You should be able to buy NEW for around $1800.... but not directly from Sensenich. They only give 10% discounts, AFAIK. Big difference. A Sen dealer in GA wanted $2525. You wanna talk nice now and do a little HOPPING for me? I have a dealer source that discounts Sensenich. If you talk real nice I might even arrange a Sensenich T-shirt for your smart ass. Damn am I humble. Barnyard BOb -- a very satisfied Sensenich customer |
#6
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"Larry Smith" Careful... or I won't save you any money on a Sensenich prop. O, I'm in milquetoast mode from now on. I guess MONEY really does talk, eh? g You should be able to buy NEW for around $1800.... but not directly from Sensenich. They only give 10% discounts, AFAIK. Big difference. A Sen dealer in GA wanted $2525. For your T-Craft... http://www2.sensenich.com/direct/tcraft.htm You want this TexASS dealer.... Stan Shannon -- http://www.kitplaneparts.com/ Psssst. Do NOT mention my name. Chances are you will get a better deal if you don't. Honest. I can explain, but not here. You wanna talk nice now and do a little HOPPING for me? I have a dealer source that discounts Sensenich. If you talk real nice I might even arrange a Sensenich T-shirt for your smart ass. Damn am I humble. If you actually order a new Sensenich prop.... I GUARANTEE you a T-Shirt from the Lititz PA factory. I will need your name address, etcetera.. if things work out. Barnyard BOb -- |
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