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- Thread starter thenated0g
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Doc J
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JustinMader
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Doc J
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ugh?
I'm no expert, but I recall they had seen that Nissan had a pretty powerful V6 for IMSA racing and that they could adopt those to air racing, but had many issues trying to keep the motors alive. I think they may have pumped them up a bit higher than race spec too... It has been a long time since reading about it. (The goal for the Pond Racer was to preserve the limited supply of vintage warbirds, this would offer an alternative.)
It was propelled by dual liquid-cooled Electramotive VG30 engines that were derived from Nissan V-6 block engines used in the 300ZX and Maxima automobiles. Fully installed with turbochargers, radiators, and ducts, the V-6’s basic weight increased from 350 pounds to 700 pounds.
The V-6 was also connected to a gearbox which brought the Racer’s wild 8,000 rpm operating speed down to a more propellor-friendly 2,000 rpm. In this respect, the Pond Racer featured four-bladed King Air props that were 80 inches in diameter, and whose knife-thin tips were designed to run at 98% of the speed of sound.
On March 22nd 1991 Dick Rutan took the Scaled Composites Pond Racer out for its first spin in the sky. Commenting afterwards, Rutan noted how the maiden voyage had been a ‘continuous engine emergency’ due to improperly calibrated powerplants.
Over the next couple of trials, the engines were adjusted and recalibrated to work well at moderate power, but even by August, they were still chronically misfiring because the engine control computers were failing to take account of air density.
Another source of trouble was the methanol fuel, which was found to be corroding the plane’s materials and contaminating the oil supply. Consequently, it became standard procedure to drain the fuel systems after each flight and refill them with aviation gasoline in order to safeguard the components from the effects of methanol.
Shoehorning the 195-cubic-inch turbocharged engines into the tight aerodynamic cowlings required compromises as well. And these highly stressed engines were required to run at full power continuously for long periods of time. Oil scavenging and supply issues dogged the aircraft during its three years in competition and resulted in several spectacular inflight failures. Although the engines ran relatively cool on methanol, the composite engine cowlings required the use of external blowers immediately after shutdown to maintain their strength.
Red
Very Strong User
I was lucky enough to be a regular Reno attendee when this was being developed, and have access to some folks around the program. I too have a soft spot for this plane, even though many of the design choices are questionable for, maybe even opposed to, going fast around a closed course circuit at low level. The concept to save the warbirds is well intended.
The Electromotive V6's were lifted directly from the then wildly successful IMSA GTP program. If you are a motorsports fan, they are stuff of legend. The major issue with them was never about available HP or even mechanically reliability, it was all thermal. It was packaged so tightly and the available cooling system volume so small, that running big HP was never really possible. Talking at length with Dick Rutan who was the development pilot, temps were at red line on the climb out from the runway. As soon as it was on the ground it was IMMEDIATELY hooked up to external blowers and cooling devices to prevent heat soak and thermal runway with the engines off lol. More often than not it landed with one engine shut down.
Ultimately the plane crashed due to fire from an failed powerplant taking the life of race pilot Rick Brickert. The right engine caught fire and the forward swept planform brought fuel into the cockpit and the associated fire with it. A shame on many levels. I can't help but wonder what might have been had the program been allowed the full development cycle. Would it have been a world beater? Probably not, but very possibly competitive and potentially an alternative to expensive and limited warbirds.
BTW, the molds still exist.
Red
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JustinMader
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Rutan has some neat concepts, but the PR has always been my fave.
Would love to get my hands on that Mantikor... almost looks like a PCM Fritz with motor pods and a tail.
Would love to get my hands on that Mantikor... almost looks like a PCM Fritz with motor pods and a tail.
gp49
Very Strong User
Are you bringing it to Los Banos with you next weekend?
jure
Very Strong User
most likely will not bring the sailboat to LB.Are you bringing it to Los Banos with you next weekend?
Other ships are competing for space in the car:
Three PSS models: Spitfire, Zero and P-38
Gliders: Magnus , Weasel , modified Radian (maybe)
Other gliders : TBD
the forecast looks good for Friday 18th , but Saturday and Sunday look dead ...
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gp49
Very Strong User
You probably should get a bigger car by now! Or, a box on top of your car (I have one that can fit a 4m glider wings, if you are interested) If you are coming on Friday bring extra ballast, if you a coming on Saturday/Sunday bring something that's self launching.
