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. ;-)

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.

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

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.

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

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.

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.

"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

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