Cook book recipe for a modern day V12 ! !

[ZOOM "Unreg"]

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

People

Mayday 51 is dead nuts on..... HOPEFULLY with the interest in a race multiple series.... if rara doesnt wany to play.... pound sand....but eventually they will come around because of $$

(the mayday51 tip will work.....with the following assumptions and present day mentality)

a) learn from the u-boats.... the honeymoon of turbines is over, people want v power and noise.... be it military v12s or monster auto v8s (1 or 2 per boat?)

a / 1) tractor pull / drags have 700 + cu in neo-auto powerplants
a / 2) gear the crank, turbo it, flatten the curve to bring the torque where it needs to be........ geeeze , bring roush in on this ..... this is dooable people!!!!!!!!!!!
a / 3) what ever happened to the I/O 720 flant 8 cylinders from cont or lyc ?????

b) the "u-lights" = more boats, cheep and real interest draw

c) When the sport class (airplanes) crack the 400 lap speeds..... BOOM, its 1964 all over again and the people will come AND people will build like never before (pilots and owners)

d) Like the ulights boats.... cheep buy in ...... and as welll , a cheep buy in for the aero guys as well

e) Turbine anything goes no where in my book (just the price of a gt is proof of that)



If i may split my thread into two groups????????

A NEW FORUM?

1) Modern day V12 (RR clone) as a wish list fourm .... ok .... cool
AND
2) Modern day Unlimited Lights form for motors AND for that matter a fourm for a whole new class...... power, airframe, EVERYTHING

This board is whitisning a birth of the air racing future and a dedicated thread category needs to be started asap ("Unlimited Lights") is as good a name as can be....


mr. webmaster ..... do you need to take a vote (users) or what?


ZOOM

[AAFO_WSagar]

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

mr. webmaster ..... do you need to take a vote (users) or what?

Make ya a deal ZOOMIE... you register, I'll think about it..

<grouchy old wayne grumbles as he heads down the basement steps once agiain to check for unregged messages in the queue>

[CoastieAux]

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

1 Lb Baby Carrots
2 Lb Red Skinned Potatos
1 Clove Garlic
2 Skinned and Dismembered Rabbits
2 TSP Celantro
8 Quarts Water
1 TSP Salt
1 TSP Pepper
1 1944 Vintage RR Merlin


Take the water and bring it to a boil. Add Salt, Pepper, Celantro and Garlic. Add Rabbits for 2 hours, then add carrots and potatos and simmer for 3 more hours.

Make an exact copy of the Merlin, eat your Rabbit Stew and shut yer pie hole.

Oh yeah, can't forget onions...add 2 for good measure.

[Race5]

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

[mayday51]

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

..........eh?!?.....


.............."what's cookin' Doc ?".......



Q: one of our mentors..."BB"

[Blue Foam]

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

... 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.

...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. ...

For this, we need to go back to the books and clarify some terminology. A turbo-compound engine IS turbocharged, NOT "supercharged". We got messy with our semantics here, so let's get back to hit-the-books-prime mover-technical terms, advantages and disadvantages and push the pause button on the hot-rod terminology.

The piston engine (as we use them here) runs on an Otto cycle of constant volume combustion and varible volume compression and expansion. Two-strokes, four-strokes, and even Wankels use this cycle.

A turbocharger runs on a Brayton cycle of constant volume compression and expansion while using the piston engine feeding it as a gas generator.

A centrifugal supercharger (as opposed to a roots or Lysholn type) is one half of a Brayton cycle, the compression half.

Applying the Brayton cycle to the inlet and outlet of an Otto cycle results in the world's most efficient prime mover architecture for any size. Additional efficiency can be gained at a specific operating point of altitude, RPM, and power setting by gearing the Brayton (turbine and compressor sections) to the piston crankshaft. For mechanical and plumbing simplicity, the turbine section(s) and compressor(s) in this type of engine are often entirely separate and not in the form of a traditional "turbocharger". This does not change the function: it is still a turbocharged, compounded engine. For a wider RPM, altitude and power range, "free" turbochargers are used.

Why is the turbo more efficient than the straight engine or an engine with only a compressor? Expansion ratio.

Engines make power by expanding a hot, high pressure gas to lower temperature and pressure and have a mechanical means of converting this expansion into torque and RPM (HP). This power is offset by the work the engine must do to get the gas to the point of combustion (intake and compression) and exhaust it once the useful work is done (exhaust). The greater the expansion and the lower the losses, the greater the efficiency.

Piston engines have awesome compression and expansion capability with minimal mechanical losses compared with all other prime movers. However, the last few points of compression and expansion tend to cost a great deal in losses vs. their gain in efficiency and specific power. So while we can operate a pump gas engine at 11:1 compression and 8:1 expansion, it is better to back off to 8:1 and 6:1 and install a 3:1 compressor, 2:1 expansion turbocharger. Total compression and expansion ratios increase to a whopping 24:1 and 12:1. Increased efficiency can be had by increasing the aspect ratio of the turbine and coupling the whole thing to the crank, but this is mechanically inconvenient and limits the efficiency gain to a narrow operating range.

Increasing compression only does increase specific power (HP/lb) and this has a secondary benefit to efficiency. This benefit is mostly offset by the mechanical loss of turning the blower; so the net gain is power, not SFC. Only by increasing the expansion ratio are REAL efficiency gains possible.

If we are worried about throttle lag, we will use a restrictive turbine and cause a significant increase in EGT. Unburned fuel in the exhaust will also raise EGT with a turbo, so a good installation requires better fuel atomization, ignition, and smaller combustion chamber sizing than any current aircraft engine.

Modern combustion chamber design and rational sizing, coupled with a large, efficient, and slow to spool up turbo yields increased efficiency, higher specific power, and lower thermodynamic and mechanical stresses all at the same time. Engine development in all other motorsports (that allow turbos) went in this direction. Post WWII aircraft engines went WAAAAYYYY too large in piston diameter and too fast in piston speed. Air racing needs a big dose of get out there and look around. More than buzz bomb imports, ship diesels have many good lessons that can be applied.

[jarrodeu]

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

So what type of supercharger does a Merlin have?
Jarrod

[440_Magnum]

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

So what type of supercharger does a Merlin have?
Jarrod

Centrifugal, driven by a gear train from the rear of the crank.

[440_Magnum]

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

so let's get back to hit-the-books-prime mover-technical terms, advantages and disadvantages and push the pause button on the hot-rod terminology.

While I appreciate the desire for accuracy, I disagree that "hot rod terminology" is entirely inapplicable. In this context, it actually makes it a lot easier to keep track of several broad categories of commonly used internal combustion engine/compressor/turbine combinations. Yes, strictly speaking a 3350 TC is turbocharged. But in practical terms, its not turbocharged in the way that one commonly applies the term. The turbine has a fluid clutch, gear train (reduction), crankshaft, and another gear train(blower drive) in the path before its recaptured power finds its way back to the compressor.

Common usage, as I see it, would be:

1) "turbocharging" when you mean a tubine/compressor on a common shaft, turbine spun by expanding exhaust gas and compressor compressing air for an IC engine.

2) "supercharging" when you refer to the generic process of pre-compressing intake charge air for an IC engine (and usually by inference a mechanical drive for the compressor)

3) "turbo-compounding" when you refer to the unique configuration of the 3350 TC (and the a very few others) that mechanically couple all 3 elements (compressor, Otto-cycle engine, and turbine).

Besides- air racers ARE "hot rods" At least no one has suggested hanging a 12-V-71 roots blower and a Hillborn scoop on a Merlin....

[Unregistered]

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

Magnum , seems like a couple 'ol hot rod boys did try to adapt a roots blown aluminum hemi for crop dusters . Don't know what ever happened to the deal after Zuechel's untimely demise . Cuz

[MerlinV12]

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

How hard is to convert merlin v12 to efi??
There are dragracing cars that have turbocharged engines pusing over 3000 + bhp whit twin turbo or more.

Would this work on a airracer??
Maby make it twin turbo or maby even quad turbo(4 turbocharges)
This would make it far than the superchagers that they have now.
And this would the ecu that could be fitted to a merlin v12.

[Wild Bill Kelso]

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

How hard is to convert merlin v12 to efi??
There are dragracing cars that have turbocharged engines pusing over 3000 + bhp whit twin turbo or more.

Would this work on a airracer??
Maby make it twin turbo or maby even quad turbo(4 turbocharges)
This would make it far than the superchagers that they have now.
And this would the ecu that could be fitted to a merlin v12.

Personally that and electronic ignition are what is need to make these engines more reliable. My father spent 20+ years at Honda R&D and when they went to (rules permitted) electronic engine management they started to come up with some badass HP. Example: Honda RC211 moto GP "Big Bang" engine. It is a V-5 that has it's crankshafts (yes two) that counter rotate(offset cranks with gear drive in center). The two slugs on one crank are a different displacement than the three on the other crankshaft. The two slugs balance the three and the three balance the two(very little counter-balance on the crank needed). All five cylinders fire in 76 degrees of crankshaft rotation. It is 998cc's and puts out OVER 200 hp at 18,500 rpm!!! A Merlin race motor or R3350 would be safer to run. Most engines are melting pistons before the pilot sees it on a gauge at race speeds. It would constantly be changing with altitude, g loads, NoS, and whatever else you throw at it. Not to mention the set and forget mixture setting... One less thing for the pilot to keep on top of and run his/her race. Drag Racers are so on top of it these days they can melt a piston RIGHT at the lights.

[ZOOM "Unreg"]

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

The Hilborne injector scoop on top of the 14/71 blower will be to high to see where you are going?
ZOOM

[First time Juke]

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

Just a tought,

How about a new V12 engine using diesel fuel..or biodiesel ? Really ecological.

rgds,

Juke

[Peashooter]

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

Spits at Reno?

http://www.dthweb.com/Html/PicturesOne.php?Translate=EN&ImageName='DX-2002-SPITFIRE-022M.JPG'