Dreadnought notes...

[BellCobraIV]

Re: Dreadnought notes...

Sometimes the posts on this board scare me...
Not one of us can EVER make fun of the Trekkies...

And afterall Leo, that is the trouble with Tribbles

[Leo]

Re: Dreadnought notes...

My....God....I'm....surrounded.

[BellCobraIV]

Re: Dreadnought notes...

My....God....I'm....surrounded.

That would be quite logical Captain,....Gearheads and tech heads combined. Slack out

[speeddemon]

Re: Dreadnought notes...

My....God....I'm....surrounded.

The scary thing is....I can HEAR it when you say it......

[BellCobraIV]

Re: Dreadnought notes...

The scary thing is....I can HEAR it when you say it......

Wouldn't it be scarier if you thought it, then he said it?
hmmmmmmmmmm?

Sorry Jedi reference wrong series!!!!!!!!!

[Apteryx]

Re: Dreadnought notes...

Sorry Jedi reference wrong series!!!!!!!!!

That's allright, the farce is with you...

[440_Magnum]

Re: Dreadnought notes...

That would have been 1986. But you still at least made the final that year.

GOD, I am such a geek!

That also answers the discussion from a few weeks back, namely "How fast would the Bear be with a stocker backup engine?"

The answer, obviously, is "fast enough to make the finals."

Too bad the changeover is so complex in this case, compared to the Mustangs going from a Thorne or Sparrow Merlin to a stocker.

[440_Magnum]

Re: Dreadnought notes...

I won't go into a lot of the details on the 3350, But I will say that we tried a Simplex ring package for the engine in either 1985 or 1986, I can't remember right now. The engine in the bear used less than a half gallon between Van Nuys and Reno, The outside was very pristine just like what you see on the side of Dreadnought, the plugs were cleaner and we were all very happy with the results. A phone call with Charlie Thompson, who used to be "the" factory representative for Curtiss Wright on the R-3350 got the response "don't go over 50 inches MAP with those rings !" The crew chief at the time elected "NOT" to pass that information on to the pilot or the owner, but instead put together an engine break-in program to be run around the course at Reno early in race week. At the first attempt to go above 50 inches within a half lap it burned the rear master rod piston resulting in a may day. A Stock Alameda R3350-26WD was purchased from Frank Sanders and put on the airplane for the races. Part of the smoke you see from the Rare Bear is indeed oil, part of what you see coming off the bear is a rich mixture. Old timers on the crew can tell when the balance is right. In my opinion it will never be as dry as Dreadnought, but should never be as wet as in retrospect what I have seen from this past year in pictures. I don't want to go back to mud slinging about this year and turn this thread ugly, so please lets not throw any rocks.

No worries about flying mud or rocks from me, this sort of tech stuff is what I love the most. The story above perfectly illustrates why folks that race airplanes HAVE to approach any change with a lot more caution than those of us who play in other motorsports. An experiment with a new piston or ring package on an American automobile v8 may cost at most a few thousands of dollars if it goes "poof" the first time you run it hard, and replacements are readily available. A 3350 (or 4360, or Merlin, or Allison) is in a completely different cost league, not to mention you don't have to declare a "mayday" in a car when the engine goes south.

Back to rings- the strange stuff that goes on inside engines never ceases to amaze me. One of the facts I learned relatively late in learing about engines is that with ring packages, how well the package controls oil is not necessarily directly correlated with how well it controls combustion gasses. Most folks think that when an engine burns a lot of oil, it has to also be losing a lot of cylinder pressure to blow-by. After all, that's true when engines start to wear out. But if you're designing for high horsepower, its possible to put together a ring package that lets a good bit of oil into the combustion chambers, but does a great job of keeping the combustion pressure inside the cylinder. Even though the burning oil might raise the octane requirements a bit, you might still be better off than with a really really "dry" ring package that loses more pressure to blow-by. A little bit of oil on the cylinder walls can actually help the sealing (and longevity under stress) of some compression ring designs. Blow-by doesn't just cause loss of pressure, it also carries a lot of heat down to the rings where it can do damage.

IOW- the amount of oil out the exhaust is not a reliable indicator of how "tight" the engine's gas seal really is.