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Not a great color scheme for a Bearcat but they sure make good looking airracers. I can't think of any other Warbird that looks better modified than stock.

 

Steve- That thing looks even more muscle-bound than a regular bearcat. The cowl has a Tempest/Sea Fury look to it, but with a whole lot less airplane behind it.

Taz
Terry Phillips

 

A modern Gee-Bee. The torque must really be impressive.

 

Exactly what I thought when I saw it.

Can it beat a good P-51 racer?

 

In its prime there was nothing that could beat it. That thing scares me just looking at it. Steve, how does this " Boil-off cooling" work?

 

I have heard of the boil-off/ evaporative systems in the old Schneider Cup racers but never in an aircooled application unless it is a spray on or as you said to cool the oil. Still crazy. I noticed one helluva lot of right rudder trim fed , or poured, in. That is one mean looking mutha !

 

Are you kidding? This airplane, "Rare Bear", has been racing since 1969 and has won the Unlimited class at the Reno National Championship Air Races no fewer than ten times! It also holds the current closed-course record for piston-engined aircraft, having flown 528+ MPH back in 1989. When everything holds together, this airplane eats Mustangs for lunch (sorry, sparky).

http://www.rarebear.com/rarebear/records/

 

I know a lot of those guys used spray bars to hose down intercoolers and oil coolers but are usually only switched on at high boost or when the nitrous is running. The term air cooling is a little bit misleading. Most air cooled motors get a big percentage of their cooling from the oil. It absorbs a lot of the heat from the pistons and cylinders and needs a place to get rid of it. It may be this thing, to clean it up has reduced air for the oil cooler and has a total loss water cooler for the oil cooling. With that big diameter spinner the motor is not getting as much air as it used to.

I think a couple of the Mustangs that had the rad housing chopped off and went to slits in the leading edge with rather small radiators used them too. I recall the one Skip Holm flew for a few years had them. That thing had so little cooling he sat at the end of the runway until it was clear, lit the motor, did a mag check and was clean and climbing out in about 30 seconds. That thing needed a couple hundred KIAS for enough air to keep it cool.

 

Whatever happened to the chopped P3 blades Rare Bear used to have? I think it had those back when it set all the records.

I think it had the time to climb record for recips too.

 

Well, I've always been a P-51 fan, though as a former Grumman engineer I like the F8F as well. I remember when Lyle Shelton first raced the plane when it was called "Able Cat" -- it's been a long time!

Some technical details about the changes are also on the team website:
http://www.rarebear.com/bear_facts/

 

Thanks for the last 2 pictures Steve. They answered our question about the cooling. Have a look at the oil cooler inlets on the Bear when it had the P3 blades and compare to the inlet size in the new pictures.
The inlets look half the size or so, no doubt to clean it up. No idea where the outlet is or what they did there.

 

In my opinion I wouldn't think that reducing those inlets is going to have much of a change to reduce drag. Still a big hole in the leading edge. An NACA ramp type inlet somewhere on the smooth surface of the fuselage or even under the wing would be a lot less draggy. Disrupting the flow at the leading edge spreads it aft over that portion of the wing. I think that a regular old scoop, properly designed would be better a hole in the leading edge.

 

I won't argue that. You know a hell of a lot more than me about aerodynamics but they are a bunch smaller and I suspect it is connected to their need for their boil off oil cooling system

 

Like that little German guy used to say on Laff-In, " VEDDY INTERESTING."

 

One of the worst things that they did on the Comet was the engine inlets in the wing root. They had to split the wing spar for the intake air ducts that ran through the most voluminous area of the wing thus robbing it of fuel storage. Then , of course, the spars developed cracks and they had to rework them. The intakes disrupted the airflow at a portion of the wing that needed all the drag reduction that it could use. So, the fuel tankage was so diminished that they had to resort to slipper tanks hung from the outer wings where they should have hung engines so they could use the inboard wing space for fuel. Wing sweep was not enough to raise the Mach cruise to competitive levels and then the sharp square corners of the ADF windows led to the cracks that led to catastrophic failure of the fuselage structure. BUT the British were absolutely magnanimous to publish all this (the fuselage failure) so that no one else would commit the same mistake. Do you think that Airbus would do that?

 

I suspect not.

Interesting info. I had heard of the famous windows but had not heard the other points.

 

It is really crazy how this forum subject matter can slide from one subject into another without you knowing it. Like this reparte' began with a photo of Rare Bear and steam and segued to scoops and the Comet ADF windows. That's the fun of it, tho.

 

The Comet spars had to accommodate the passage of the intake ducts AND the engines therefore they had great big holes in them. The inboard sections of the spars were "aluminium" forgings. Engine maintenance was difficult and engine removal was almost as difficult as a Ferrari. The windows or any openings on the 707 were framed in a forging or had doublers and triplers to spread the loads. I remember some mechanics called them tic-tac-toe plates because of the legs that spread out from them. The fuselage skins had tear-stopper strips at each frame so any tear in the skin would travel only to an adjacent frame and no further. The Comet ADF windows had doublers around them but they were attached by hundreds of closely spaced 3/32 rivets and the driving of so many closely rivets work hardened the material and added to the propensity to crack. They even found where cracks had been stop-drilled on the Comet fuselage assembly line. When the square corner of the window developed a stress riser, the crack went from hole to hole and finally down the entire length of the fuselage. Explosive decompression happened in less than 1/10th of a second. Fuselage paint found on the upper wing skin near the tip led the inspectors to look at the fuselage wreckage and they determined what had happened and why.

 

I hate myself ! The rivet sizes were not 3/32 but 5/32.

 

And here I thought you knew what you were talking about!


Sheesh


Myself, I have a great memory, it's just short.

 

I just make all this stuff up and it doesn't help when my fingers type things that don't match what is in my head...but then how could they when everything is so scrambled up.
That was an exciting time from 1954 through the 60's when we were doing the 707, 720, 727, Kc-135. There didn't seem to be enough time to get things settled on one model before another new one popped up. The Brits had the jump on everyone when they did the Comet but there were too many design flaws that killed it.