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Pazmany PL4
"Rich S." wrote in message
... "JohnO" wrote . . . The Nigerian Airforce has RV6's. France had some Emeraudes, but they were the certified European production model. Does that mean that RV6's, Emeraudes, and any other of the ilk are qualified to park on the Warbird line? That'd be kinda neat! Those big iron drivers always seem to get good parking and "crew members" with great looking tushes. ) Rich S. Those alleged crew members are actually "Hangar Princesses" since those old heavy iron warbirds are the real "Hangar Queens" Peter Striving for accuracy and tradition in nomenclature. ;-) |
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Pazmany PL4
On Feb 24, 9:17 am, "(Keith Sowter)"
wrote: Why were there not many Pazmany PL4's built ? Here's one I saw Fly back in 1982 at Red Deer Alberta http://www.abpic.co.uk/photo/1019962/ Here's what I said about it on my website on VW powered homebuilts: "Conventional gear single seat low wing all metal T-tail Aerobatic. Laszlo got tired of taking heat for how long it took amateurs to build PL-2's, and the energy crisis was upon us, so he designed a VW-powered plane that only took 3000 hours instead of 6000 hours to build. The belt reduction 1600cc engine didn't make the power he thought it would, and very few, if any, other than the prototype, were actually built with the engine it was designed for. A rugged, well engineered airplane, with exceptional plans and builder's manual. I'll say that again, you will not find a finer set of plans, and the assembly manual is a complete education in building a metal airplane. I'll bet with a bigger engine, and one of the Smith Engineering belt reductions that GPASC sells it would go pretty good." I've since heard from Veeduber (who knew Pazmany, and flew out of the same airport as the prototype) that you could smell the first ship before you could see it, as it burned, errr flew off the first 40 hours with the belts constantly slipping. They ARE hell for stout, plus/minus 9G I think. |
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Pazmany PL4
On Feb 25, 10:58 pm, flybynightkarmarepair wrote:
I've since heard from Veeduber (who knew Pazmany, and flew out of the same airport as the prototype) that you could smell the first ship before you could see it, as it burned, errr flew off the first 40 hours with the belts constantly slipping. ------------------------------------------------------------------ Well... mebbe it wasn't quite that bad... :-) But with multiple vee belts it's impossible to keep ALL of them at the same tension. The loosest of them would slip and there was a definite pong of hot rubber after every flight. Several of us who had experience flying behind VW's (Paz wasn't a pilot back then) tried to explain the realities of VW engines to Paz but he made it pretty clear that our experience-based opinions were not welcome. (Come to think of it, a kid named Burt Something did exactly the same :-) In the final analysis the PL-4 -- at nearly 700 pounds -- is a heavy, complex, expensive airframe that needs more power than a stock 1600 VW engine can provide. With the same engine, a Teenie Two can fly rings around it and is a lot easier to land, while a VP-1 is more fun than either. But of course, those aren't 'real' airplanes... :-) -R.S.Hoover |
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Pazmany PL4
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Pazmany PL4
cavelamb himself wrote:
Beryl wrote: wrote: On Feb 25, 10:58 pm, flybynightkarmarepair wrote: I've since heard from Veeduber (who knew Pazmany, and flew out of the same airport as the prototype) that you could smell the first ship before you could see it, as it burned, errr flew off the first 40 hours with the belts constantly slipping. ------------------------------------------------------------------ Well... mebbe it wasn't quite that bad... :-) But with multiple vee belts it's impossible to keep ALL of them at the same tension. The loosest of them would slip and there was a definite pong of hot rubber after every flight. Eh? I can't visualize it. Either all, or none, slip. Nope. That's not how it works, Beryl. Oh, maybe if all the belts really were teh exact same size. Or if the pulleys were really exactly parallel. In the real world neither of thoese little details ever work out - quite that exactly. The biggest one slips. How can you tell which is the biggest one? Easy. It's the one that slips! As tehy say, YMMV... Richard My mileage varies. I tink teh biggest belt is just along for teh ride. And in teh real world, even teh tightiest belt slips if you're talking about microscopically wobbling pulleys. |
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Pazmany PL4
On Feb 26, 8:23*am, cavelamb himself wrote:
Beryl wrote: wrote: On Feb 25, 10:58 pm, flybynightkarmarepair wrote: I've since heard from Veeduber (who knew Pazmany, and flew out of the same airport as the prototype) that you could smell the first ship before you could see it, as it burned, errr flew off the first 40 hours with the belts constantly slipping. ------------------------------------------------------------------ Well... mebbe it wasn't quite that bad... :-) *But with multiple vee belts it's impossible to keep ALL of them at the same tension. *The loosest of them would slip and there was a definite pong of hot rubber after every flight. Eh? I can't visualize it. Either all, or none, slip. Nope. *That's not how it works, Beryl. Oh, maybe if all the belts really were teh exact same size. Or if the pulleys were really exactly parallel. In the real world neither of thoese little details ever work out - quite that exactly. The biggest one slips. How can you tell which is the biggest one? Easy. It's the one that slips! As tehy say, YMMV... Richard- Hide quoted text - - Show quoted text - Caveman, you cannot have one belt slipping and not the others. Think about it - the pulleys on each shaft are all the same size and rotating at the same speed. You can only have slip if one pulley is rotating at a different speed to the other. If one slips they *must* all slip. |
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Pazmany PL4
"Beryl" wrote in message ... wrote: On Feb 25, 10:58 pm, flybynightkarmarepair wrote: I've since heard from Veeduber (who knew Pazmany, and flew out of the same airport as the prototype) that you could smell the first ship before you could see it, as it burned, errr flew off the first 40 hours with the belts constantly slipping. ------------------------------------------------------------------ Well... mebbe it wasn't quite that bad... :-) But with multiple vee belts it's impossible to keep ALL of them at the same tension. The loosest of them would slip and there was a definite pong of hot rubber after every flight. Eh? I can't visualize it. Either all, or none, slip. I must admit that I am having a little trouble visualizing this one as well--unless that loosest belt was either the farthest from the engine or the farthest from the prop. In those cases, I have no trouble at all. Peter |
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Pazmany PL4
Peter,
It really doesn't matter WHERE in the lineup the longest belt is. You can have two, or "very many", and absolutely none of them will be the exact same length. One WILL be longer than all the others, and (by very keen observation it will be also found) one of them will be shorter than all the others. Always, one will carry more torque, horsepower, heat, friction, wear (or your malady of choice) than others and share the rest of the difficulties among its companions, and will lead to premature failure of one belt or another. Those difficulties, along with uneven stretch pattern among the individual belts - thus making it hard to maintain proper tension on each and every belt in the setup, is what gave rise to the new style of belts and pulleys. Even pulleys that are quite carefully manufactured will still have the grooves nearly exactly same angle and depth and diameter- but never exactly. It is actually kind of like shooting fish in a barrel with a shotgun. You have just got to wait and see what comes to view after all the smoke clears. The plane and installation in question did not take advantage of the "poly-V" single belt with multiple grooves - much like the serpentine alternator belt on your 1980 F-150. And the "cog" type belt, as in timing belts and synchronized drives was not an option then, either. Multiple vee-belts were a compromise solution, and the difficulties associated with that solution were what came along with the perceived benefits, like rpm, power, weight, cost. Flash "Peter Dohm" wrote in message . .. "Beryl" wrote in message ... wrote: On Feb 25, 10:58 pm, flybynightkarmarepair wrote: I've since heard from Veeduber (who knew Pazmany, and flew out of the same airport as the prototype) that you could smell the first ship before you could see it, as it burned, errr flew off the first 40 hours with the belts constantly slipping. ------------------------------------------------------------------ Well... mebbe it wasn't quite that bad... :-) But with multiple vee belts it's impossible to keep ALL of them at the same tension. The loosest of them would slip and there was a definite pong of hot rubber after every flight. Eh? I can't visualize it. Either all, or none, slip. I must admit that I am having a little trouble visualizing this one as well--unless that loosest belt was either the farthest from the engine or the farthest from the prop. In those cases, I have no trouble at all. Peter |
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