Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
Yeah its too bad these and or similar engines aren't powering the aircraft of nowdays, instead of jets.
If this was a diesel with a .25 BSFC in a TC configuration, the fuel savings would be fantastic compaired to turbines.
The maintenance costs would have been enormous. Plus the wide profile meant there was going to be quite some drag created.
It looks like from the photo this engine may be at the Udvar-Hazy annex of the Smithsonian in northern Virginia...I'm way overdue for another trip there.The original test engine was later delivered to the Smithsonian Institution, where it was recently restored.
Second the comment on the Lycoming R-7775 being way too heavy.
A P&W R-2800 CB16 (or a -99W military engine) engine would do 2500 HP (wet) takeoff for 2390 pounds (source"R-2800; Pratt Whitney's Dependable Masterpiece" by Graham White). Doubled and you have 5000 HP takeoff HP from 4780 pounds, compared to the 6050 pounds for the Lycoming. The weight difference is even more pronounced since the weight of the R-7775 does not include the radiators, which a R-2800 does not need. Two R-2800s could drive a single propeller if needed; use the military -50 drive drive nose case, and then a remote combining gearbox, much like Bristol did with the coupled Centaurus engines in the Babrazon airliner.
If you just have to have liquid cooling, couple two R-R Griffon 57s (like two Allison V-1710s were coupled to make the V-3420). Each Griffon 57 gives 2450 HP take-off from 2020 pounds. Coupled you would have 4900 HP from 4040 pounds or less.
Piper106
I love these hyper engines. They are huge, complicated and so powerful. And, when at their zenith, along comes something that looks like a glorified stove pipe and it makes more power. It is like the last days of the dinosaurs.
My car has overhead cams, fuel injection and a turbocharger. Cars have finally evolved to the level of WWII aircraft. )
A powerful engine but not powerful for that amount of weight. I can see why they were told to dump it on the ground.
Lycoming R-7755 - Wikipedia, the free encyclopedia
The Lycoming R-7755 was the largest piston-driven aircraft engine ever produced; with 36 cylinders totaling about 7,750 in³ (127 L) of displacement and a power output of 5,000 horsepower (3,700 kilowatts). It was originally intended to be used in the "European bomber" that eventually emerged as the Convair B-36. Only two examples were built before the project was terminated in 1946.)