Warbird Information Exchange

I'm sure this post should be in the air racer area, but maybe not. Are the unlimited air racers all engine? or a combination of airframe and engine, I'm sure both, but what racer has the most powerful engine and if you took that engine and put it on another completely different airframe do you think that racer would be even faster? That's assuming the engine and airframe could work together.

Last question, of all the WW2 warbird designs, which one is deemed the fastest?, not counting the 262.

Hellcat,

As unlimited air racers became faster over the years, it was by leaps and bounds (a little sarcasm - each mph is hard fought).

As time went by, the Merlin was refined by Dwight Thorn. The Rare Bear crew and Dave Cornell made the -3350 a real race engine, and the Sanders figured out how the R-4360 is supposed to work at high power.

Stega's record breaking 466 mph back in the 90's is still pretty quick today, but it isn't front-running by today's standard. That was Dwight and his engine, Kerch and his airframe, and a wiley guy named Tiger willing to run at meltdown power.

You just aren't going to go fast without big HP. Miss America, not a stroked-our racer like Dago Red, went 425 with big HP. Dago Red used to do 440 with a Mike Nixon engine back in the early 80s. It did better than 500 with the last version of Thorn's Mouse Motor in the early 2000s.

So, in short, I think you always have to start with the biggest HP you can run, and run it reliably. Then you have to pay strict attention to the airframe, systems, and choose a pilot that can translate all that into speed on the course.

With Dago Red, that last 15 mph is black magic as far as most are concerned. It's 700 different little things done to the airplane that combine to get that speed.

Here is one little item: seal the seat attach tubes so air does not leak between the bottom fuselage and cockpit. In other words, sealing the interior of the airplane prevents air from getting inside and causing drag.

_________________
Scotty G
www.LightAndLift.com
www.WarbirdAeroPress.com

It takes a lot of horsepower to overcome a little drag, but it is hard to get a watercooled engine to run max power for the entire race without overheating.

bdk,

The real race engines, liquid cooled as you said, are not running at max power. They're running *way* over that.

The low-boost, high rpm setup favored by Jack Hovey runs around 95 inches and 3700 rpm. Oil temp problems become very common. Answer? More spraybar water over the oil cooler/heat exchanger.

Thorn favored the high boost, "low" rpm setup. Up to 145 inches at 3400 rpm. Undoubtedly, this is the more robust setup and has gone the fastest at Reno. This is the vaunted Mouse Motor, and uses case beefup, an amalgam of different parts, and the famous big Allison rods. There is so much more to it.

Engine cooling is a function of the cooling properties of the radiator/heat exchanger, the coolant pump functioning as required, and the spraybar that shoots water/alcohol over the face of the radiator. The scoops on the racing Mustangs are cut way down, and basically only admit enough air to carry the spraybar fluid to the face of the radiator. Most of the cooling is by heat transfer of the fluid. It comes out as fluid, flashes to steam at the face, and that is what you see trailing racers like Dago Red and Strega.

Spraybar pump failure? Better have an auto backup or pull the power wayyyyy back so you don't cook the engine. Land. But in normal race ops, engine cooling isn't really a factor. Interior parts getting confused, induction temps that are too high, and related system failures are more to blame.

Mike Barrow is on here often, and he can provide much more info than I have. Maybe even disagree about some things. (vbg)

Hope this helps.

_________________
Scotty G
www.LightAndLift.com
www.WarbirdAeroPress.com