Sweet Sounds of Allison

[FightinBluHen51]

Re: More Floating V-12 Images from BEARFAN1

Originally posted by AAFO_WSagar
Yet another

Those look to be like two huge Garret baised Turbos. Probably a t-76 or larger frame. So...if the superchargers on the merlins take HP to run (as with any S/C), why doesn't someone take and TT (twin turbo) or QT (quad turbo) one?? Think it would be rather interesting to see it done myself.

[W J Pearce]

Misc.

No one makes the WWII engines, either V or R. The Allison puts out 1710 cu in. The Cat engine is close in displacement to the Merlin. Cat is not concerned with an engines weight in a dozer while in and aircraft, weight is critical.

A few people have worked on a turbo setup for the Merlin, but none have raced (I think). John Sandberg (SP?) had a turbo set up on his P-39 which was Allison powered, but it never seemed to get to the top.

It is very hard to make parts for old engines after the tooling has been destroyed. I have a friend that makes Ardun heads for flat head Fords and also GMC 302 Wayne heads. They have the patterns but still have casting difficulties. An aircraft engine is much larger and more complex, thus a whole lot more expensive and difficult.

What some have looked into is having countries with WWII technology (developing) manufacture part for the merlin and others. I don't know how extensive of a parts run but it is a cool idea. Labor is cheap and they have the tooling just sitting around because there isn't a whole lot to build.

That's it for my ramble, the above is based on memory and my not be entirely accurate.

Hey BluHen... how did a college kid on the East Coast discover/get interested in Air Racing?

Bill Pearce

[FightinBluHen51]

Re: Misc.

Hey BluHen... how did a college kid on the East Coast discover/get interested in Air Racing?

Bill Pearce

Excelent Question. Um, believe it or not, I just got interested in aviation again (loved it as a little kid) and I was looking for something else to get involved with besides my auto message boards. Then, after seeing a special on the history of air racing on D-Wings channel, it kinda got me hooked.

As for the tooling, I understand that it is hard recreat it, but aren't the plans still around for the motors and parts?? I understand that a little company would not have the resources to build the tooling, but wouldn't be benificial for someone to start making these kinds of things again?? I mean couldn't a company that makes sport ai craft engines find some uses for these motors?? Just a thought.

[Unregistered]

Originally posted by FightinBluHen51
[B]

Is RR still making merlins/griffons or small plane motors??

No, and they haven't for decades. I don't know exactly when Griffon production shut down, but after the Dart turboprop took off, RR never built any more reciprocating aircraft engines at all.

How bout anyone still making the Rounds??

Not in the US, that I know of. Wright and P&W built piston engines a lot longer than Rolls did, but they were pretty much done by the late 1950s too. For that matter, the whole Wright *company* was done after the 3350- they just hung on too long and neglected turbines, and got killed in the process.

Spares? Those went on for a lot longer, I guess, because the USAF kept some R-2800s and R-4360s in service (reserves) well into the 1970s.

I know for fact that Catipiller ( the machinery company) is making a v-12 turbo deisel that displaces 1649 cubic inches (this baised off the Allison motor??)

You GOTTA be kidding. I doubt there's even a nut or washer that will interchange.

So, isn't it possible to find blocks and the like to keep building these things without having to scrape to find the nistolgic pieces?? [

Nope. There are some components being built new, but nothing approaching a whole engine. "The Doctor" has said before that no one seems willing to step up and build some of the more complex parts (such as fork connecting rods) that are needed. Just because Carillo and Ross build millions of Ch*vy rods and pistons per year doesn't mean they even have equipment capable of building a Merlin part.

[FightinBluHen51]

In ref. to the Cat. Diesel v-12

[i]
You GOTTA be kidding. I doubt there's even a nut or washer that will interchange.
[/B]

I know some of those companies have been mixed up and I didn't know if a good thing had just stayed around or if something new had come threw. (Though it was at least a reasomable question cause sometimes old technology is the best).

[AAFO_WSagar]

Originally posted by FightinBluHen51
I know some of those companies have been mixed up and I didn't know if a good thing had just stayed around or if something new had come threw. (Though it was at least a reasomable question cause sometimes old technology is the best).

A reasonable question but the useage of the Cat diesel would commonly be totally different in application. A quick "for instance" would be that in some installations of an industrial engine like the Cat, the engine would actually act as a stressed member of the chassis. It's pretty common to see an industrial engine serving as, at least, a part of the stressed frame between the front and rear axles. This is something you could never do with the highly stressed and very light engines that are created for airplanes.

Another quick "for instance" would be the Merlin, as used at Reno, in the Dwight Thorne style race engines. The basic "frame"of the engine is so highly stressed and light that when "hot rodded" as done by The DOCTOR and his followers, it can not withstand the stress of the torque and needs to be reinforced to keep the case from twisting and taking the bearings out..

Industrial and aviation engines are built with two completely different end uses in mind. Not that you could not adapt a very heavy engine to racing or a very light aircraft engine to what is essentially an industrial use (like tractor pulling for an example) it's just not that practical to do it.

Good question though.

Wayne

[Unregistered]

Originally posted by FightinBluHen51
In ref. to the Cat. Diesel v-12



I know some of those companies have been mixed up and I didn't know if a good thing had just stayed around or if something new had come threw. (Though it was at least a reasomable question cause sometimes old technology is the best).

Apologies if what I said came across as a smack-down... it sure wasn't meant that way, but reading it now I can see how it might have been. It was supposed to be funny... :-)

Wayne hit the nail on the head- a Merlin might look fairly big, and it might produce unholy amounts of horsepower in the hands of our resident DOCTOR, but you would never, ever want to base an industrial engine off of it because its actually very "lightly" built.

First, just look at materials- A Merlin is mostly aluminum with magnesium bits here and there to even further reduce weight. Big industrial diesels like Cat, EMD, and GE are made of massive quantities of cast iron.

Second, look at size. They're HUGE compared to a Merlin. A General Electric 7FDL V16 locomotive diesel engine typically produces 3000 HP (the newest FDLs produce 4400, beyond that GE had to go to the HDL engine). Now look at an FDL compared to a Merlin! It occupies the whole center section of a locomotive, and stands taller than a man, and its *tons* of weight are actually a benefit because it aids the loco in getting traction. Yet the engine in Dago Red can (for a little while) put out the same raw HP. But the locomotive engine is expected to do it literally for hours without a break, and for years without an overhaul.

Third, look at operating conditions. Diesel engine designers aim for long-term reliability- thinking thousands of hours between overhauls, and trying to reach that goal with NO breakdowns. They consider it "out on the edge" when the BMEP (brake mean effective pressure- think of it as the average pressure on top of the piston) gets up around 300-400 psi. Good grief, man, thats not THAT much more than the pressure in the *intake* manifold downstream of the blower on one of the air race v12s at race power, let alone on top of the pistons!

Its the ultimate example of "different strokes for different folks." Just a completely different application.

[Vlado]

I don't think a Merlin has any Magnesium.

[Unregistered]

Diesels

I believe the CAT weighs around 4000 lbs., compared to the Merlin's 1500 ???? The Cat makes it's hp's at only 2100 rpm, and uses 2 piece pistons with steel tops to withstand the heat. You rarely see diesels run over 45 boost, although I saw a truck that ran 132 boost to do it with a Cummins straight 6 of only 855 cu. in. displacement. Double that to be a V-12 and you get 1610 cu. As a past diesel mechanic, I can tell you that you don't run a diesel at higher rpm's to get hp's. You run manifold pressure, by huge injectors, large turbos, high injector pump rail pressure of over 300 psi.. The rotational mass is harder on the engine at high rpm's than making the hp's at lower rpm with more boost. You may need to get a more efficient prop for lower rpm or a box to increase the propeller rpm of current props. By the way, the roller cam was developed for diesels originally, not cars. They are needed to run the steep cam profiles for making high torque, not rpm's as in auto engines. Now you can get some lighter weight diesels such as Yanmars, (have one in a boat) and you can get the smaller ones to run continuously at 3000 rpm's, with short duration runs of 3600 rpm. Not for use over a couple of minutes. You must also get rid of massive amounts of heat. Notice how large a truck radiator is for engines of 800-1200 cu. in.. Also, you can run bio-diesel in a 20-40% additive to diesel to make it burn clean and put back in some of the lubricity that has been lost on low sulphur reformulated diesel sold today. It increases the cetane level (what diesels require as opposed to octane) and runs better and smells like french fries. Also bio-diesel works very well as a cleaner of both parts and hands.

[FightinBluHen51]

Sorry I haven't been around for a while, been kinda crazy with getting ready for college again. Thanks for the info, some of which you actually touched upon stuff that I did know, but hey, its always fun to read it again. I knew you weren't laying a smack down, and its all good. Like I said, I didn't know if CAT or Detroit had just "remanufactured" the allsion engine for its diesel apps. ect, meaning that their equipment would still transfer over today. (Which if it worked for that, then recoupe the cost of the development). You guys did answer another question that I had which was in reference to the material that merlins are made out of (to my surprise you said aluminum/magnizium instead of iron). Reno is coming up fast, so, my learning curve needs to speed up some, but I think the books are gonna start getting in the way in about a week and a half.

[Unregistered]

Vlado says no Magnesium in Merlins- I'll buy that :-)

There is a lot of Aluminum, and the American round-motor builders experimented a lot with magnesium. One of the reasons that an engine fire on a B-29 is such a Really Bad Thing is all the magnesium used in the first-generation R-3350. Magnesium burns really easily, and REALLY hot.