Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: MachFly on November 05, 2011, 10:48:24 PM
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I know P-38 has counter rotating props, but is it just the props or are the engines counter rotating as well?
Thanks
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It was equipped with "handed" engines....the engines turned opposite directions.
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It was equipped with "handed" engines....the engines turned opposite directions.
One of the reasons it was so expensive.
- oldman
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Thanks for clarifying
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Is it the engines turned in opposite directions or just the camshafts? I know some WWI fighters had engines that rotated but thought all WWII radial engines and inline ingines were stationary with the exception of the camshaft/drive shaft.
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I always thought that on a P-38 the left engine had a gear box on it to change the direction...
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Is it the engines turned in opposite directions or just the camshafts? I know some WWI fighters had engines that rotated but thought all WWII radial engines and inline ingines were stationary with the exception of the camshaft/drive shaft.
Wiseguy! :D
It's the crank that turns opposite direction.
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From Wiki with reference from "Americas Hundred Thousand"
Counter-rotation was achieved with the use of "handed" engines, which meant that the crankshaft of each engine turned in the opposite direction of its counterpart. The V-12 engines only required that the spark plug firing order be changed in order for the direction of the crank shaft to be reversed, according to the General Motors Allison V1710 Service School Handbook.
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One can download the service manual from https://rs232tl.rapidshare.com/#!download|232tl4|391852386|Allison_Service_Handbook.pdf|115839|R~704745CD4DF5F414BF8532BE3FDEDE50|0|0
There was an extra gear installed to get the cam shafts to rotate the same direction in the right and left engines.
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Since it seems to be a bad link, try http://www.ww2aircraft.net/forum/engines/allison-v-1710-service-manual-upload-24875.html
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One can download the service manual from https://rs232tl.rapidshare.com/#!download|232tl4|391852386|Allison_Service_Handbook.pdf|115839|R~704745CD4DF5F414BF8532BE3FDEDE50|0|0
There was an extra gear installed to get the cam shafts to rotate the same direction in the right and left engines.
Been there.....seen the setup that allows reverse rotation.
There are many other engine peripherals that also need changing.
Most obvious is the starter but many accessory driven devices need to be tailored for reverse rotation or they won't work such as prop governers and oil pumps.
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Been there.....seen the setup that allows reverse rotation.
There are many other engine peripherals that also need changing.
Most obvious is the starter but many accessory driven devices need to be tailored for reverse rotation or they won't work such as prop governers and oil pumps.
This is the main reason why many twins weren't built with counterrotating props. The logistics involved became too much and too expensive. This is also why the P38 is such a unique aircraft.
:salute
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The Allison V-1710 was designed from the beginning to run in either direction. You change an Allison from a left hand engine to a right hand engine mostly by how you assemble it, not by changing a great number of parts.
The gearbox is changed because when spun the other direction, the direction of thrust changes as well.
The gear box is really the only major difference, and did not increase the cost of the Allison that much.
The Lightning was expensive because it was very complex, and required special fixturing and close tolerance assembly. Steve Hinton once said it was one of the most elegant and exotic designs of the era.
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On a V1710, you have to change oil pump or it's drive, prop governor and it's drive, camshaft, timing advance mechanisms, supercharger drive or impellers, and the rest of the accessory drives...........or........yo u can just make a gear case that turns the prop in the opposite direction like we do in boats.
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Question, weren't the lend lease versions fitted with props going in the same direction?
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The Lightning was expensive because it was very complex, and required special fixturing and close tolerance assembly. Steve Hinton once said it was one of the most elegant and exotic designs of the era.
The P-38 is a very interesting aircraft, it's history isn't really well known ... Howard Hughes began designing a plane in the mid 30s that would incorporate modern developments, some of which were "anticipated" but not yet realised. Eventually it became the D-2 and was envisioned as a Long Range Fighter / Bomber with internal bomb bays. Hughes built it in secret with his own $$$. He always maintained and later testified before congress that the P-38 was STOLEN & COPIED from his design and adapted for production as a fighter with existing technology by Lockheed. The D-2 never saw service, Huges -REFUSED- to sell it to the Army. But it later served as the starting point for the Hughes XF-11, a post war, high altitude reconnaissance aircraft that eventually led to the U-2 and SR-71 spy planes ...
Both the D-2 and the XF-11 -LOOK- like scaled up P-38s and are often mistaken as an evolution of the Lockheed fighter. :old:
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Question, weren't the lend lease versions fitted with props going in the same direction?
There were no "lend lease" versions. The British wanted P-38's, without counter rotating engines and propellers, and without turbochargers. Lockheed engineers did not want to accept the order, they knew the P-38 would not perform in that configuration, but they did accept the order. The British, who actually named the P-38 "Lightning", did not like what they asked for, of course. Lockheed let them out of the contract, and the USAAC bought the planes for use as trainers.
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The P-38 is a very interesting aircraft, it's history isn't really well known ... Howard Hughes began designing a plane in the mid 30s that would incorporate modern developments, some of which were "anticipated" but not yet realised. Eventually it became the D-2 and was envisioned as a Long Range Fighter / Bomber with internal bomb bays. Hughes built it in secret with his own $$$. He always maintained and later testified before congress that the P-38 was STOLEN & COPIED from his design and adapted for production as a fighter with existing technology by Lockheed. The D-2 never saw service, Huges -REFUSED- to sell it to the Army. But it later served as the starting point for the Hughes XF-11, a post war, high altitude reconnaissance aircraft that eventually led to the U-2 and SR-71 spy planes ...
Both the D-2 and the XF-11 -LOOK- like scaled up P-38s and are often mistaken as an evolution of the Lockheed fighter. :old:
The history of the P-38 is actually quite well known, and most factually documented by former Lockheed engineer Warren Bodie, in his book, "The Lockheed P-38 Lightning". No, Clarence E. "Kelly" Johnson did not steal any part of the P-38 design from Howard Hughes. I seriously doubt the man who led the team that gave us the P-38, the F-104, the U-2, and the SR-71 needed to steal designs from anyone.
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The history of the P-38 is actually quite well known, and most factually documented by former Lockheed engineer Warren Bodie, in his book, "The Lockheed P-38 Lightning". No, Clarence E. "Kelly" Johnson did not steal any part of the P-38 design from Howard Hughes. I seriously doubt the man who led the team that gave us the P-38, the F-104, the U-2, and the SR-71 needed to steal designs from anyone.
But think about it, if he truly DID steal the designs for the p38, he wouldn't just come out publicly and say it in his book would he? that would pretty much discredit him from the achievements of the p38.
One of those things we may never know.
Ether way, im just glad it was built.
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Interestingly the Westland Whirlwind prototype had counter rotating props but that feature was dropped from the production versions even though the Rolls Royce Peregrine engine's output could be easily handed.
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But think about it, if he truly DID steal the designs for the p38, he wouldn't just come out publicly and say it in his book would he? that would pretty much discredit him from the achievements of the p38.
One of those things we may never know.
Ether way, im just glad it was built.
You may never be sure, but I feel comfortable crediting Mr Johnson with the airplanes and Mr Bodie with the book.
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I can understand Hughes' position...
(http://upload.wikimedia.org/wikipedia/commons/7/79/Xf11_usaf.jpg)
That's the XF-11. Basically an upscaled D-2.
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There are some that say Hughes was influenced by the P-38, not the other way around. Bob Gross, the head of Lockheed at the time was a good friend and confidant of Hughes and both held regular discussions on aviation design. Also, the P-38 started development in 1937, Hughes didn't start to design the D-2 until 1939, after the P-38 was accepted and test flights already started. The first flight of the D-2 wasn't until summer of 1943 that the D-2 prototype was flown in secret, some 3.5 years after the first test flight of the P-38.
The time line just doesn't hold weight for the notion that the idea of the P-38 was stolen from Hughes' D-2 design, if anything it lends credence to the opposite argument that the D-2 was influenced by the P-38, as the D-2 was seen really nothing more as an upscaled P-38.
Supposedly the only known photo (bottom picture) of the D-2 sitting prior to test flight.
(http://img206.imageshack.us/img206/4867/d22nr1.jpg)
ack-ack
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Johnson favored the twin tail design going back to 1933 with his work on the Lockheed Electra while he was still at the University of Michigan. So I seriously doubt he stole the idea from Hughes.
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P-38's Suck
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Also, the P-38 started development in 1937, Hughes didn't start to design the D-2 until 1939, ... The time line just doesn't hold weight for the notion that the idea of the P-38 was stolen from Hughes' D-2 design,
Supposedly the only known photo (bottom picture) of the D-2 sitting prior to test flight.
(http://img206.imageshack.us/img206/4867/d22nr1.jpg)
Hughes began putting his idea on paper in 1931 or 32 I think, he was inspired according to one OLD Hughes Aircraft engineer while watching a close formation flight demonstration (overlapping wings) of (PT22?) trainers. And possibly? by the twin booms of the original Wright Flyers which impressed him with their structural strength to weight ratio. He had a LOT of associates at lockheed and was known for his open and detailed discussion of ideas with both engineers and mechanics. CONSTRUCTION of the D-2 is what started in 1939, not design. The 1st prototype never flew, Hughes scrapped it and started over.
There are at least several photos that survive of the D-2 under construction. The idea that Hughes copied the p-38 originated with some of the congressmen who insisted he be investigated after he refused to tell them all his "secrets." As I said this isn't well known - officially approved "History."
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Ether way, im just glad it was built.
Amen! Hughes wasn't interested in giving the army what it wanted and needed ... If his design was co-opted, it was likely done for the good of the country and whoever made that judgment call has been vindicated completely by the outstanding accomplishments of the aircraft and it's timely availability when the country needed it ... :salute
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But think about it, if he truly DID steal the designs for the p38, he wouldn't just come out publicly and say it in his book would he? that would pretty much discredit him from the achievements of the p38.
One of those things we may never know.
Ether way, im just glad it was built.
Its just plain wrong to imply things this way. You should apologize.
Infidelz.
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Perhaps they were both influenced by another design...
(http://www.scenicreflections.com/files/Fokker%20G1%20Wallpaper__yvt2.jpg)
The Fokker G.I was introduced to the world at the Paris Air Show in November 1936.
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Perhaps they were both influenced by another design...
(http://www.scenicreflections.com/files/Fokker%20G1%20Wallpaper__yvt2.jpg)
The Fokker G.I was introduced to the world at the Paris Air Show in November 1936.
Twin boom concept was more common than people think. Fokker G.I was nothing new.
Before WWII, many manufacturer were experimenting with twin boom designs, some go back to WWI, among them Albatros, Blériot, Arado, Blohm & Voss, Curtiss, Fokker, Kalinin, Saab, Savoia-Marchetti, Sikorsky, Vultee, Weymann, to name just a few.
I'm pretty sure neither Hughes nor Lockheed copied each other's design.