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Agreed shortround. Kind of in the likeness of the Packard V-1650-3 vs V-1650-7 in the Mustang.
Jeff
The Thunder Mustang is very impressive but it doesn't hold that initial rate for very long.
One clue is the 24,000ft service ceiling.
Another is getting 640hp from 601 cu in at 4800rpm. Anybody got any details on IF the engine has a supercharger?
Since the air at 10,000ft is 73.8% as dense as it is at sea level the engine will make 73.8% of the power unless the supercharger set up is rigged to accommodate the pressure/density drop.
For comparison stock Bearcats had either a bit under 2100hp at sea level which increased to 2100hp at a bit over 3000ft and then tapered off to a bit over 1650hp at 10,000ft on the early ones (78.5% sea level power) without water injection, 115/145 fuel or shifting into high gear. The later ones (using 115/145) had 2200hp at take-off and still had 1975hp or so at 10,000ft.
I don't know what Rare Bear was using for power when it set the record but some R-3350 engines in Skyraiders ( source for Rare bears first engine?) were rated at 2700hp for take-off and 2700hp at 3700ft military power dry.
Without some form of supercharger the Falcon engine is going to be down almost 8% in power at 3700ft. (590hp?)
Rare Bear didn't have any guns, ammo, armor and had lighter fuel tanks than the military self sealing tanks and likely lighter radios/avionics. The Wright engine and new prop were heavier than stock though.
A Military Bearcat clean but fully loaded weighs just about 3 times what a Thunder Mustang does yet has 3.28 times the power at sea level and may have 3.48 times the power at 10,000ft (early one) to 4.15 times the power at 10,000ft for a late one.
With Rare Bear being both lighter and more powerful than a stock Bearcat a Thunder Mustang is going to need a LOT of power to take the record away.
Yep, a Thunder Mustang would require a blower to be competitive in this event...I didn't take into consideration what altitude does to engine performance...
One clue is the 24,000ft service ceiling.
Another is getting 640hp from 601 cu in at 4800rpm. Anybody got any details on IF the engine has a supercharger?
Since the air at 10,000ft is 73.8% as dense as it is at sea level the engine will make 73.8% of the power unless the supercharger set up is rigged to accommodate the pressure/density drop.
It also means you need about 4 times (or just under) the weight of nitromethane for the same power as gasoline. Switching fuels in flight is not practical without a complete secondary fuel system. For a 5-10 minute record run it might be possible, it is going to ake longer to descend and land that than the climb up.
" Exhaust gas from an internal combustion engine whose fuel includes nitromethane will contain nitric acid vapour, which is corrosive, and when inhaled causes a muscular reaction making it impossible to breathe. People exposed to it should wear a gas mask."
Which is not really a problem for the pilot as he may be on oxygen anyway. It may be a problem for the aircraft unless quick washdowns/decontamination are done on landing.
"Nitromethane is usually used with rich air/fuel mixtures because it provides power even in the absence of atmospheric oxygen. When rich air/fuel mixtures are used, hydrogen and carbon monoxide are two of the combustion products. These gases often ignite, sometimes spectacularly, as the normally very rich mixtures of the still burning fuel exits the exhaust ports. Very rich mixtures are necessary to reduce the temperature of combustion chamber hot parts in order to control pre-ignition and subsequent detonation. Operational details depend on the particular mixture and engine characteristics."
A reason for the long zoomie headers on fuel dragsters. Get the flames away from the car body. Drag of 2-3ft long header pipes on an aircraft???
Regular Methanol is a much better fuel for record setting aircraft. It is a lot less twitchy. It allows for more power than gasoline because you can burn twice as much per pound of air and it has a lower flame temperature than gasoline which helps with the cooling load.
The nascar engine may need a supercharger as the engine will loose almost 20% in power by the time it reaches 10,000ft.
Pilot interview for 0-3000meter climb record flight:
Team manger to pilot "well, Jim Bob (pilot) we reckon we got a good chance of setting the record, we got the power and we figure that there is only about 10-20% chance of the engine grenading on any given record attempt flight. Pay is $1000.00 a week, $500.00 a record attempt flight with a bonus for setting the record and we provide the parachute and repacking of the parachute at no cost to you. Whatdo you say? take the job?"