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01-23-2007, 06:05 AM

Mark Hickey wrote:
> A Muzi <am@yellowjersey.org> wrote:
>
> >As a classic car buff, I learned fast that total production is a BIG
> >factor in whether or not you can afford the thing. My Corvairs went to
> >nearly two million copies and many service parts are shared with all
> >Chevy sixes (1955~1980) so they are cheap to run and hop up. Every piece
> >you want is available and cheap. These mills are currently powering
> >brand new sport planes (November cover Sport Flying) 38 years after
> >'death'.
>
> That reminds me of one of the actual real advantages of a rotary, at
> least for aircraft use. If you lose the cooling system on a
> water-cooled aircraft motor, you can get into big trouble - you won't
> get far before the piston engine gets too hot to continue running, and
> then if you're not within gliding distance of a suitable landing
> place, you're gonna make the evening news.

Can't really think of a general aviation A/C with liquid cooling tho.
None of the ones I have flown, bunch of Cessnas from 150/2 thru the
T-210. Military trainers, none were, T-34, T-28. Even WWll, except for
the Merlin/Griffon types, most were aircooled radials.
>
> A rotary OTOH will continue to run virtually forever (at a somewhat
> reduced power level) until you can get the plane safely on the ground.
> It'll be a "throw-away" at that point, but would have potentially
> saved the aircraft and the pilot/passengers.
>
> Another benefit of the rotary is that they have a very smooth power
> output at the crankshaft. This has huge benefits for an aircraft, and
> the PSRU (Propeller Speed Reduction Unit) which gears down the prop
> speed allowing the engine to run in its efficient RPM range without
> sending the propeller tips into the (noisy and inefficient) supersonic
> range (that's the noise you hear when aerobatic planes do vertical
> dives). The lack of extreme "power pulses" puts a lot less stress on
> the PSRU and propeller (which can be destroyed by the pulsating power
> output of a piston engine in certain situations).
>
> >A vehicle or power plant with 100K copies is not going to be a cheap
> >project over the long run.
>
> True enough... as an owner of a mid-80's Alfa Romeo, I know the pain
> of trying to find parts for an "unusual car"... (the oil pump I just
> bought set me back over $250).
>
> Mark Hickey
> Habanero Cycles
> http://www.habcycles.com
> Home of the $795 ti frame

01-23-2007, 06:05 AM	#129 (permalink)
Qui si parla Campagnolo Guest Posts: n/a	Re: OT Interesting video Mark Hickey wrote: > A Muzi <am@yellowjersey.org> wrote: > > >As a classic car buff, I learned fast that total production is a BIG > >factor in whether or not you can afford the thing. My Corvairs went to > >nearly two million copies and many service parts are shared with all > >Chevy sixes (1955~1980) so they are cheap to run and hop up. Every piece > >you want is available and cheap. These mills are currently powering > >brand new sport planes (November cover Sport Flying) 38 years after > >'death'. > > That reminds me of one of the actual real advantages of a rotary, at > least for aircraft use. If you lose the cooling system on a > water-cooled aircraft motor, you can get into big trouble - you won't > get far before the piston engine gets too hot to continue running, and > then if you're not within gliding distance of a suitable landing > place, you're gonna make the evening news. Can't really think of a general aviation A/C with liquid cooling tho. None of the ones I have flown, bunch of Cessnas from 150/2 thru the T-210. Military trainers, none were, T-34, T-28. Even WWll, except for the Merlin/Griffon types, most were aircooled radials. > > A rotary OTOH will continue to run virtually forever (at a somewhat > reduced power level) until you can get the plane safely on the ground. > It'll be a "throw-away" at that point, but would have potentially > saved the aircraft and the pilot/passengers. > > Another benefit of the rotary is that they have a very smooth power > output at the crankshaft. This has huge benefits for an aircraft, and > the PSRU (Propeller Speed Reduction Unit) which gears down the prop > speed allowing the engine to run in its efficient RPM range without > sending the propeller tips into the (noisy and inefficient) supersonic > range (that's the noise you hear when aerobatic planes do vertical > dives). The lack of extreme "power pulses" puts a lot less stress on > the PSRU and propeller (which can be destroyed by the pulsating power > output of a piston engine in certain situations). > > >A vehicle or power plant with 100K copies is not going to be a cheap > >project over the long run. > > True enough... as an owner of a mid-80's Alfa Romeo, I know the pain > of trying to find parts for an "unusual car"... (the oil pump I just > bought set me back over $250). > > Mark Hickey > Habanero Cycles > http://www.habcycles.com > Home of the $795 ti frame