Upper limit on R-3350 in horsepower.

[Leo]

Re: Upper limit on R-3350 in horsepower.

Blind Man's Bluff (Critical Mass) was originally set up for alcohol.
As I remember they had nothing but problems and a hard time starting it. I don't remember what they were using as a starter fluid but I DO remember a crew member getting burned.

[matt]

Re: Upper limit on R-3350 in horsepower.

bill, the sea fury you mean was blind man's bluff (now critical mass, which now runs on avgas...), if memory serves correctly they burned up 6 engines race week because they did not adjust timing for the higher octane fuel (alcohol i believe).

i have been wrong before though.

[440_Magnum]

Re: PW 2800 on putting out 4 or 5 grand!

Wayne- don't bother posting the un-regged response I just sent. Dang' ol different computer. :-p

Let's remember that the 6000 HP 3350 ran on pure methanol. Not ADI and not Avgas+ADI. Champ cars run on pure methanol. Many, many classes of dragsters and other racers run on pure methanol. If anyone wants a list, it's a BIG LIST. Sparrow and Slacker both reported here that addition of water-methanol ADI requires "de-riching" to increase power; i.e. they are BURNING the methanol.

An engine running on alcohol and atmosphere has to burn the alcohol. How else does an alcohol engine run?

Engines set up to run ON methanol ingest it with air at such a ratio so that the mixture is above the LEL for methanol. No problem in explaining that.

But this is where things get a little more fuzzy for me:
The 2800 article clearly implies that so long as the percentage of alcohol in the ADI is such that the resulting mixture is below the LEL for the alcohol, it doesn't skew the overall mixture. Use methanol, no problem. Substitute isopropyl at the SAME air/fuel ratio and the SAME ADI ratio, suddenly the engine is running too rich to function. The difference is the LEL for the different alcohols.

As far as "de-riching" I agree that would tend to imply that the methanol is contributing to the combustion. Or.... is it just that by bringing the gasoline/air ratio back closer to stoichiometric (which is made POSSIBLE by the addition of ADI so that excess fuel doesn't have to be run through the engine in order to prevent detonation) a net power increase is observed by de-riching? I don't know.

[Peashooter]

Re: PW 2800 on putting out 4 or 5 grand!

Let's remember that the 6000 HP 3350 ran on pure methanol. Not ADI and not Avgas+ADI. Champ cars run on pure methanol. Many, many classes of dragsters and other racers run on pure methanol. If anyone wants a list, it's a BIG LIST. Sparrow and Slacker both reported here that addition of water-methanol ADI requires "de-riching" to increase power; i.e. they are BURNING the methanol.

An engine running on alcohol and atmosphere has to burn the alcohol. How else does an alcohol engine run?

So what's the fuel flow at 6,000 hp with methanol? Crikey!

[Ken Dwelle]

Re: Upper limit on R-3350 in horsepower.

Magnum, you are correct.

"Or.... is it just that by bringing the gasoline/air ratio back closer to stoichiometric (which is made POSSIBLE by the addition of ADI so that excess fuel doesn't have to be run through the engine in order to prevent detonation) a net power increase is observed by de-riching? I don't know."

There is a line from the ADI regulator to the carburetor. When the carb senses ADI pressure, it de-riches to a more ideal fuel/air mixture. At higher power settings, the mixture control has to go from auto lean to auto rich. This provides extra cooling at the expense of a less than ideal mixture. The ADI provides the cooling, which makes possible a better mixture to make more power.

Ken

[wingman]

Re: Upper limit on R-3350 in horsepower.

Thanks for that Ken -- I've been wondering for a while about de-riching.
I don't remember all the details, but in an interview with Bruce Lockwood a couple of years ago, he talked about making (or getting) a de-riching apparatus for Dago in the late 1990s. He said it made a significant difference in speed, and in the happiness of the motor. That was the first time I ever heard of the process.

So how long has de-riching been done in the Unlimiteds, and who developed it? It seems like the development process would be difficult, as you're dealing with motors at high power settings on the ragged edge of detonation, and nobody could afford to destroy too many engines making this thing work...

Neal

[2101]

Re: Upper limit on R-3350 in horsepower.

Best power is obtained with a fuel-air ratio of aprox .80 The combination of pressure and temp of the charge will cause detonation at higher power settings.In auto-rich the mixture is about .10 This produces a 6-8% drop in power below best power.ADI is used to replace the excess fuel to suppress detonation.This brings the power back up to best power.In addition the power can be increased another 6-8%. Derichening is part of the original system.On a R-2800 this was good for 300 hp.This is all taken from PW literature. Regarding dynoing large radials.Its already built in.Torque pressure is a system that gives a reading of how much torque the engine is producing which can be converted to hp.Basically the reduction gears are helically cut planetarys.The outer gear is held in position by pistons.The more torque the higher pressurebecause the gears try to walk apart, and by reading this pressure you get a raw number that can be converted to torque and knowing the rpms,horsepower.

[wingman]

Re: Upper limit on R-3350 in horsepower.

So de-riching was part of the system on R2800s? I would assume this would be true only on those with a factory ADI or water injection? Did Merlins ever have a factory de-rich system? What about a dash 9 in a P-51H, which is described as having water injection? Is this the same as ADI? Certainly up to recently one would often see racing Mustangs trailing a bit of dark smoke, which I always thought indicated a very rich mixture, to prevent detonation at high power settings.

I guess it shows that I am a photographer, and not an engine person...

Neal

[TJ Dwelle]

Re: Upper limit on R-3350 in horsepower.

From memory:
Bradley C Miller is the guy who did the dyno ing of the Skyraider engines.
They were buying them in the can for $5500 each. They melted down quite a few of them. Mr. Miller rebuilt an old dyno he located in Hondo Texas. He said it was a dry break variety so that they could roll up another engine and plug it in. 5000 hp was not a problem and BBB was running 4500 HP at Reno. They planned to "change the bullet every night," so the crew was pretty good at changing engines. He ran it in High Blower always. Ken, correct me if I'm wrong, CM and Bear run in low blower.

I've got 2 guesses as to why they built a dyno:

1. They didn't understand the torque pressure set up?
or
2. They were all well paid engine guys happy to spend Levolor's money.

[440_Magnum]

Re: Upper limit on R-3350 in horsepower.

From memory:
Bradley C Miller is the guy who did the dyno ing of the Skyraider engines.
They were buying them in the can for $5500 each. They melted down quite a few of them. Mr. Miller rebuilt an old dyno he located in Hondo Texas.

Some INTERESTING stuff comes out of Hondo. I think it was a couple of years ago that a couple of R4360s and R3350s showed up on some auction site, they were in Hondo. They were in various levels of completeness, but IIRC at least one may have been a "canned" engine.

I've got 2 guesses as to why they built a dyno:

1. They didn't understand the torque pressure set up?
or
2. They were all well paid engine guys happy to spend Levolor's money.

Hmmm... ;D

How accurate is the torque meter setup? I had always been under the impression that it was great for telling if your engine was putting out all that it should/could/normally would or if it had lost power from a baseline reading, but wasn't real accurate on an absolute scale. Or maybe the dyno was built for Merlins and Allisons that don't have torque meters.

[King]

Re: Upper limit on R-3350 in horsepower.

Some INTERESTING stuff comes out of Hondo. I think it was a couple of years ago that a couple of R4360s and R3350s showed up on some auction site, they were in Hondo. They were in various levels of completeness, but IIRC at least one may have been a "canned" engine.

There is an interesting gentleman who lives just outside of Hondo. He is a "trader" who collects stuff from around the world, mostly South America. He has one of the coolest "junkyards" around. You name it, he probably has it. From airplane parts to machine tools. I was out there last month and saw several cans around and other radial engines on stands. Several aircraft in various states of dis-repair including a Stinson Gullwing at the coverning stage with two sets of wings. He had just sold the DC-3 and it was moved over to the airport in Hondo.

[cwestholt]

Re: Upper limit on R-3350 in horsepower.

in the early '90's the bear produced as much as 4200 hp, but these days i don't think it produces quite so much.

there are no prt's on the bear, but it does use water methanol injection and as far as i know doesn't use no2.

The Bear definatly uses n02. Theres a big fiberglass tank in the hell hole just for that purpose.There are 2 injectors just inside the air intake inlets wich we never used and there are 2 more just above the carb intake on the home made intake manifold. The outboard wingtips are filled with water that is sprayed through an oil cooler via a spray bar for cooling.

-C