Cook book recipe for a modern day V12 ! !

[AAFO_WSagar]

Re: Cook book recipe for a modern day V12 ! !

I believe a supercharger can provide a higher pressure, but robs crankshaft power to do so. Turbos are basically free extra horsepower as they recover energy lost out of the tailpipe.

Ok I been workin all day long so I'll jump in here.. It's sort of a myth that Turbos are "free" energy.. They create back pressure, which takes energy to overcome. Yep they create more HP and I believe, yes, they are less of an energy "thief" than a SuperCharger is but Turbos do take energy to spin...

Engine Guru's.. care to eleaborate?

[Air Race Addict]

Re: Cook book recipe for a modern day V12 ! !

I was wondering what the advantages and dissadvantages of turbochargers vs. superchargers?
Thanks,
Jarrod

In my honest opinion, turbo = lighter, smaller, cheaper, easier to maintain and control, more flexible in placement, and as Wayne mentioned, not totally free, but definitely "free-er". I believe that's why you see them in higher numbers in passenger cars and many aircraft of all recip types. In my opinion, (and somewhere in the back of my 50 year old brain I think I remember being told that in A&P school forever ago. ME PULEEEEEEEZ
Bill

[Unregistered]

Re: Cook book recipe for a modern day V12 ! !

Heres just some thoughts.How about a rotary? Mazdas race engines were high horsepower and the rotors can be stacked into any amount you want.Run this into a radial or PT-6 style reduction gear.And the frontal area becomes the size of the pilot as the rotors are very small in cross section.Vibrations can be a prob with rotaries.And Mazdas rotaries were heaps better engines than the Pond racer used.Turbos would be easier to put on a radial as the exhaust is more advantageous then a V motor(less pipes hanging in the wind.Turn the impellar down to just the slinger ring for fuel distribution(thats how it works now).Waynes correct about the backpressure and a certain amount of thrust can be obtained from the stacks which would also be lost.Propellors are a big limiter,everyone is talking about the wing approaching mach,the prop tips are there way before the wing. Bill

[spacegrrrl]

Re: Cook book recipe for a modern day V12 ! !

Sadly as I understand it rotaries are not allowed in unlimited. :-(

Michele

[Stevo]

Re: Cook book recipe for a modern day V12 ! !

There are a few aircraft already running around with converted Mazda Rotary engines. This website (and this one too) has some info on these engines and their use in aircraft... as far as using one for racing

[First time Juke]

Re: Cook book recipe for a modern day V12 ! !

The thing that is sad now is that the silly "John Parker" minimun weight rule forces you to build a bigger (or at least heavier) airplane than might be optimal.

Michele,

What is this rule ? I am interested.

rgds,

Juke

[spacegrrrl]

Re: Cook book recipe for a modern day V12 ! !

Unlimited aircraft now have a minimum ramp weight. Something like 4500 pounds is memory serves. The speculation was this rule was added to keep John Parker from trying to run a hotter motor in his small "stang" and enter it in the unlimited. This is why I've heard this new weight rule refered to as the "John Parker weight rule". I personally believe anything that limits new racers for the unlimited class is a mistake.

Michele

[jarrodeu]

Re: Cook book recipe for a modern day V12 ! !

I believe that the Pond Racer would have been excluded as well due to the weight restriction.
Jarrod

[W J Pearce]

Re: Cook book recipe for a modern day V12 ! !

I believe that the Pond Racer would have been excluded as well due to the weight restriction.
Jarrod

You are correct, along with David Rose's Renegade.

[ZOOM "Unreg"]

Re: Cook book recipe for a modern day V12 ! !

People,

If i may jump in.... what is the reasoning that the weight limit is "specifically" @ 4,500#?

what is the weight of tsumani
what is weight of pond
what is weight of the falconer 51
what is the weight of a ________________ (fill i other DOA projects or on-going projects

what is the projected weight of some of the "exmples" of new designed racers shown on the thread

what is (was) the weight of the x-owner designed (race pilot) .....the spiked nosed ,trike-gear , rear push motor plane that was on e-bay

My point is to group plane gross weights (< 4500)with non-traditional , alternate prime movers to see a trend in what is out there

I think the operative word @ Reno is "piston power" motor rule

ZOOM

[W J Pearce]

Re: Cook book recipe for a modern day V12 ! !

All the non-RR/Allison/Wright/P&W powered racers that have been built are under 4500 lbs (DG-1, Renegade, Pond Racer, JP 350, Mach Buster, that Pony Express thing). This also includes the Thunder Mustang. It should be noted that most of the lightweights never made it to Reno and those that did never did very well.

The 4500 lb empty weight rule was put into effect by RARA before PRS this year. It was done out of safety concerns of visibility and wake turbulence. Some Unlimited pilots agree with the rule and some do not.

Given the opportunity, I bet both Parker and Greenamyer would have raced as Unlimited this year. They would have won the bronze (going by the official times).

The safety issues are legitimate. Sea Furies and Yaks don't get along too well nor do Tigercats and anything else. Whether the rule is right or wrong is a matter of opinion.

In my opinion, new Unlimiteds should be encouraged and as safe as possible.

[Apteryx]

Re: Cook book recipe for a modern day V12 ! !

SIGNIFICANT POINT- this "rule" ONLY applies at RENO, It's RARA's sandbox, and they simply don't want to play with John. Issued under the quise of a safety limit, for the pilots "protection", in turbulence.
Some aircraft function well, in turbulance, (read Sea Furies), some don't. I think that it should be up to the pilot to decide the risk, unless a demonstrated danger exists.
As hopefully other race venues open, I think there will be a place for the Parkers, Garbers, Elbarto's... of the world, with sleek designs, and it might just force RARA to open it's eyes...
The supply of Warbirds is limited, and the operational costs will limit the amount of actual RACING they will be able to do, in a year.
If I want to put a turbo'd IO-390 in a Cassutt, and go chase The Bronze guy's, that should be my prerogative, silly as it may be...

Paul

[W J Pearce]

Re: Cook book recipe for a modern day V12 ! !

Paul,

Personally I agree with you. If you can qualify (which also means getting your race ticket at PRS) then you can race. And in order to get to PRS, your wacky one-off design must have completed flight testing.

[mayday51]

Re: Cook book recipe for a modern day V12 ! !

Well.....

....(not that they are the best example)...How about following the Unlimited Hydro bunch...

.........."unlimited Lights" ?.....open engine (piston)...4500# max empty wt....
................(or appropriate ).......

.....there has been a murmor for a different class...("jets are boring")....
.....here is one possible answer.....

[440_Magnum]

Re: Cook book recipe for a modern day V12 ! !

Ok I been workin all day long so I'll jump in here.. It's sort of a myth that Turbos are "free" energy.. They create back pressure, which takes energy to overcome. Yep they create more HP and I believe, yes, they are less of an energy "thief" than a SuperCharger is but Turbos do take energy to spin...

Engine Guru's.. care to eleaborate?

You got it. The energy used to compress the incoming air has to come from *somewhere* and no matter what method is used to capture the energy (gear train or exhaust turbine), the energy to run the compressor ultimately comes from the engine's output itself. The trick is that either type of drive can ultimately improve the overall efficiency of the engine package, even though it does divert some power to the engines "internal use."

Turbos do have some practical advantages in that they provide more flexibility of installation, and also are better at recapturing the heat energy of the exhaust and putting it to work. Note: this does NOT mean that mechanical blowers are necessarily inherently less efficient- if the designer can adjust the valve and spark timing with a blower so that the exhaust gas temperature is lower than without the blower, then the same goal is achieved. But turbos just inherently do this a bit better.

Note also that (AFAIK..) the MOST efficient piston aircraft engine ever produced did not use turbochargers. The good ol' Wright 3350 turbo-compound used its exhaust-driven turbines to couple power captured from exhaust heat DIRECTLY to the crankshaft, not to compress the charge air. That job was still done by a mechanically driven blower. That engine package had a specific fuel consumption that was amazing, and I'm not sure that it has been beaten by high-efficiency turbofans yet or not.