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Off Topic - Spruce Goose
We have all seen the film of the Spruce Goose lifting off the water for a
few seconds only to be retired to its hangar never to fly again but I wonder, what would its performance have been? Did Hughes determine in that brief hop that the aircraft was no good or did ecconomic concerns ground it? There are all kinds of aircraft performance analysis programs available now. Has anyone ever plugged in the Goose specifications and determined how it would fly? |
#2
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Good question! I've often wondered about that myself.
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#3
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"Steve Beaver" wrote ...
We have all seen the film of the Spruce Goose lifting off the water for a few seconds only to be retired to its hangar never to fly again but I wonder, what would its performance have been? Did Hughes determine in that brief hop that the aircraft was no good or did ecconomic concerns ground it? I believe he discovered the airplane didn't have enough power to fly out of ground effect even at empty weight. Others say that he had to fly one time to collect the money from the contract. In either case, it's been shown that it wouldn't have flown with a full load. Rich |
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"Richard Isakson" wrote in message ... "Steve Beaver" wrote ... We have all seen the film of the Spruce Goose lifting off the water for a few seconds only to be retired to its hangar never to fly again but I wonder, what would its performance have been? Did Hughes determine in that brief hop that the aircraft was no good or did ecconomic concerns ground it? I believe he discovered the airplane didn't have enough power to fly out of ground effect even at empty weight. Others say that he had to fly one time to collect the money from the contract. In either case, it's been shown that it wouldn't have flown with a full load. Rich The prototype Hercules used 8 Pratt and Whitney R-4360 of 3500 HP each - the wrong engines. The 5000 - 7000 HP Lycoming XR7755, then under development, was the intended engine. The Convair B-36 and the Northrop B-35 were also supposed to use the R7755. See: http://www.aviation-history.com/engines/xr-7755.html With a total of 56,000 HP instead of "just" 28,000 the "Spruce Goose" would have been a outstanding success - don't blame the failure on the airframe. It's interesting to speculate how these huge aircraft would have performed with the enormous Liquid cooled Lycoming. Bill Daniels |
#5
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"Bill Daniels" wrote in message
link.net... The prototype Hercules used 8 Pratt and Whitney R-4360 of 3500 HP each - the wrong engines. The 5000 - 7000 HP Lycoming XR7755, then under development, was the intended engine. The Convair B-36 and the Northrop B-35 were also supposed to use the R7755. See: http://www.aviation-history.com/engines/xr-7755.html With a total of 56,000 HP instead of "just" 28,000 the "Spruce Goose" would have been a outstanding success - don't blame the failure on the airframe. It's interesting to speculate how these huge aircraft would have performed with the enormous Liquid cooled Lycoming. Are plans available? Rich "Sharpening my chisel" S. |
#6
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Bill Daniels wrote:
The prototype Hercules used 8 Pratt and Whitney R-4360 of 3500 HP each - the wrong engines. The 5000 - 7000 HP Lycoming XR7755, then under development, was the intended engine. The Convair B-36 and the Northrop B-35 were also supposed to use the R7755. See: http://www.aviation-history.com/engines/xr-7755.html With a total of 56,000 HP instead of "just" 28,000 the "Spruce Goose" would have been a outstanding success - don't blame the failure on the airframe. Well, maybe. According to the website you referanced the R7755 burned 580 gallons per hour at 5,000 HP. For the Goose that would mean 8*580= 4,640 gallons an hour or 27,840 pounds an hour. Nothing like burning 13 TONS of fuel an hour! However, according to http://www.sprucegoose.org/Specification.htm, the Goose had a payload of 65 tons (130,000 pounds). It also says that the cruise speed was supposed to be 175 mph. Lets we were going to fly it from San Francisco to Honolulu (which seems to me to be a reasonable mission). We've got a fair tail wind and we are going to get 200 mph groundspeed. We are going to throttle back to 6 tons an hour. Thats a 2400 mile flight that will take 12 hours and burn 72 tons of fuel. Looks to me like we were going to need fuel about a hour before we got to Hawaii. Now maybe the "payload" number on the sprucegoose website is after full fuel. Maybe the R7755 were lighter than the R4360. It certainly seems to me that it was doubtful that the goose could have had met its intended use. It's interesting to speculate how these huge aircraft would have performed with the enormous Liquid cooled Lycoming. Indeed. -- Frank Stutzman Bonanza N494B "Hula Girl" Hood River, OR |
#7
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Frank Stutzman wrote:
Bill Daniels wrote: The prototype Hercules used 8 Pratt and Whitney R-4360 of 3500 HP each - the wrong engines. The 5000 - 7000 HP Lycoming XR7755, then under development, was the intended engine. The Convair B-36 and the Northrop B-35 were also supposed to use the R7755. See: http://www.aviation-history.com/engines/xr-7755.html With a total of 56,000 HP instead of "just" 28,000 the "Spruce Goose" would have been a outstanding success - don't blame the failure on the airframe. Well, maybe. According to the website you referanced the R7755 burned 580 gallons per hour at 5,000 HP. For the Goose that would mean 8*580= 4,640 gallons an hour or 27,840 pounds an hour. Nothing like burning 13 TONS of fuel an hour! However, according to http://www.sprucegoose.org/Specification.htm, the Goose had a payload of 65 tons (130,000 pounds). It also says that the cruise speed was supposed to be 175 mph. Lets we were going to fly it from San Francisco to Honolulu (which seems to me to be a reasonable mission). We've got a fair tail wind and we are going to get 200 mph groundspeed. We are going to throttle back to 6 tons an hour. Thats a 2400 mile flight that will take 12 hours and burn 72 tons of fuel. Looks to me like we were going to need fuel about a hour before we got to Hawaii. Now maybe the "payload" number on the sprucegoose website is after full fuel. Maybe the R7755 were lighter than the R4360. It certainly seems to me that it was doubtful that the goose could have had met its intended use. It's interesting to speculate how these huge aircraft would have performed with the enormous Liquid cooled Lycoming. Indeed. I don't know if it is true or just hanger talk but I've always heard that aeronautical engineers say it is impossible for a bumble bee to fly. However we all know they do it well. I would like for someone to plug in aircraft performance analysis programs a bubble bees specifications and see if it is possible for him to fly. OH well it probably won't work because a bumble bee isn't an aircraft, or is he? |
#8
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The Hughes Flying Boat was intended to fly in ground effect.
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#9
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The Hughes Flying Boat was intended to fly in ground effect.
Wow, never heard that before!! What's the reference? thanks Ed Wischmeyer |
#10
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"Frank Stutzman" wrote in message ... Bill Daniels wrote: The prototype Hercules used 8 Pratt and Whitney R-4360 of 3500 HP each - the wrong engines. The 5000 - 7000 HP Lycoming XR7755, then under development, was the intended engine. The Convair B-36 and the Northrop B-35 were also supposed to use the R7755. See: http://www.aviation-history.com/engines/xr-7755.html With a total of 56,000 HP instead of "just" 28,000 the "Spruce Goose" would have been a outstanding success - don't blame the failure on the airframe. Well, maybe. According to the website you referanced the R7755 burned 580 gallons per hour at 5,000 HP. For the Goose that would mean 8*580= 4,640 gallons an hour or 27,840 pounds an hour. Nothing like burning 13 TONS of fuel an hour! However, according to http://www.sprucegoose.org/Specification.htm, the Goose had a payload of 65 tons (130,000 pounds). It also says that the cruise speed was supposed to be 175 mph. Lets we were going to fly it from San Francisco to Honolulu (which seems to me to be a reasonable mission). We've got a fair tail wind and we are going to get 200 mph groundspeed. We are going to throttle back to 6 tons an hour. Thats a 2400 mile flight that will take 12 hours and burn 72 tons of fuel. Looks to me like we were going to need fuel about a hour before we got to Hawaii. Now maybe the "payload" number on the sprucegoose website is after full fuel. Maybe the R7755 were lighter than the R4360. It certainly seems to me that it was doubtful that the goose could have had met its intended use. It's interesting to speculate how these huge aircraft would have performed with the enormous Liquid cooled Lycoming. Indeed. -- Frank Stutzman Bonanza N494B "Hula Girl" Hood River, OR I suspect the 580 GPH is a gross error. Assuming a Specific Fuel Consumption of 0.42 Lbs./HP/Hr., The R7755 would have "only" used 2100 pounds per hour at 5000 HP output. Assuming 70% power at cruise the fuel consumption drops to 1470 PPH. If the engine had been developed to put out 7000 HP and the SFC came in at 0.40, the 70% cruise fuel burn would have been 1,960 PPH. All eight engines would burn 15,680 PPH or "only" 7.84 Tons per hour. Given the liquid cooling, variable cam timing and gear box the SFC might have been even lower. Bill Daniels |
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