Heinkel He 177

Discussion in 'Aircraft Requests' started by Zipper730, Jul 26, 2016.

  1. Zipper730

    Zipper730 Member

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    An online buddy asked me if I'd ask questions about the He-177 here: I agreed since I already asked some questions about the same plane and we both have unanswered questions about it.

    They both revolve around both the engines and their use

    1. Engines: The overall drag twin engines is less than four, and applies for the propellers as well. Neither of us are really sure if this applies across the board from takeoff-speed, or from cruise-speed, to Vne. We both think that low drag would have been useful for accelerating in shallow dives, but neither of us have any idea how much a difference it makes in practice.

    It's obvious that the engines were mounted fairly close to the spar, and this caused major problems with the aircraft: What isn't obvious is why this is done. Drag seems a good possibility, though she said it could be due to the weight of the engines.

    2. Use of Engines: Were the engines pulled back to the stops or pushed up a bit in dives?
     
  2. Shortround6

    Shortround6 Well-Known Member

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    I have seen an estimate of a 3% reduction in drag for the twin installation used on the He 177 vs the 4 engines. Can't remember where though :(
    Drag is drag and would apply at all speeds.
    Location close to the spar is probably due to the weight, getting the weight close to the CG and keeping engine mounts short for the dive bomber pull out. Could be wrong.

    Most aircraft used part throttle in a dive. It was sometimes a bit of a balancing act depending on propellers. after a certain speed in the dive the airstream is trying to drive the engines, too low a throttle setting and props act like airbrakes. Too high a throttle setting and you risk overspeeding the engine and wrecking it. Most engines would tolerate some degree of overspeed (v-12s better than radials) at part (1/4?) throttle. This also depended on the pitch range of the propeller as those planes that the pilot had manual control of the pitch were set to the coarsest pitch possible before a dive bomber style attack. This is in general as a few planes did try using the prop as a speed brake. Usually this didn't work as it placed a large strain on the prop and reduction gears in the opposite directions that they were designed for. This could be made to work but required heavier prop hubs and reduction gears (and housing/bearings) than normal.

    Although not definitive I hope this helps. Perhaps someone has a pilots manual that would describe the dive procedure of the he 177.
     
  3. Zipper730

    Zipper730 Member

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    Was this estimate made before or after it flew? If I do my math right that would bring the top speed down by about 10 mph. A heavy bomber with a top-speed of 335-340 mph would outperform most of the rest.

    Like flexing?

    Okay

    It's definitely a start

    I hope so!
     
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