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Thread: Question for the engine guys: Merlin/Griffon Boost Engine??

  1. #1
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    Question Question for the engine guys: Merlin/Griffon Boost Engine??

    I've heard that back in the thunder boat days that Harrahs tried to run the supercharger on either a Merlin or a Griffon using a V6 GM engine... apparently, for whatever reason, it didn't work out (fairly spectacularly if memory serves correct) but it strikes me as a pretty neat idea... if, it would work..

    Wondering just how much of the total engine output goes into creating the squeeze? Could something like a second "boost engine" be something that would answer the low boost issues with the plentiful small blower Griffs? Would it be legal?

    Laid in bed trying to get to sleep last night thinking of how the power controls would have to be set up, pilot workload.. etc.. Wild Bill, you got your finger on the pulse..

    Is this a hair brained idea , or... could it work?

    Speedy, you remember anything about the Harrahs project where they tried this?

    Wayne Sagar
    "Pusher of Electrons"

  2. #2

    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    If memory serves me correctly at 1 time I heard that the supercharger on a Merlin took well over 1000 HP to produce race level boost. Would think that the extra weight would be detrimental to having a second engine to run the supercharger as well as the question of what removing that would do to harmonics and loads within the engine. If one could get away with no Supercharger I would think that a Turbocharger would be the way to go but again what effects the G loads would have on that size turbo would be interesting.

    Hopefully one of the V engine Guru's will chime in and tell me how much Crack I am smoking..............

  3. #3

    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    in sport class we had a white lightning that had a small eng driving a supercharger
    sounded really odd taxiing out of the pits

  4. #4

    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    I think most attempts at reinventing the blower wheel have not fared so well. If I was to go and try and do something different I would use a more modern impeller design. The "guru's" that I know and listen to told me that it would be the smartest thing to do, and so far they have been right about many other things. Who am I to argue?

  5. #5
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    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    I guess there must be a feasible [tight-rope] balance between those pressures
    that may be reliably/efficiently developed by mechanical pumping
    & those made by chemical [fuel] means..

  6. #6
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    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    Yes, I talked with Dixon about this setup a few years ago, since he was actually working on the crew in 1966 for part of the season. It was Harry Volpe's idea to put the Buick engine up front to run the supercharger on the Allison. There apparently was a direct linkage from the throttle of the Allison to the Buick...so as one accelerated, the other did too...but they had a hard time syncing the rpm's up. Not sure if they didn't think of that aspect, or they tried, or something, but Dixon said that the Buick would bog down at times and couldn't turn the supercharger fast enough to give it enough boost. Not sure if it was a torque or RPM issue. They tried that setup experimentally in 1966, as well as all of 1967...when it replaced the big Aux-stage Allison.

    They gave up and went to a Griffon engine in 1968.

    PIcture is from the Newton Marine website.
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  7. #7

    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    Quote Originally Posted by Wild Bill Kelso View Post
    Who am I to argue?
    Wild Bill of Course!!!

    And just for purely theoretical gibberish

    1200 HP to drive a Merlin blower at race power, Stuffing an engine that could come even close to that HP into an airframe, cool it, carry fuel for it........
    So lets say a race Merlin runs at 120 inches to develop 3000?HP at the prop shaft and 1200 HP to drive the supercharger for a gross of 4200HP. If one were to remove the supercharger it would take around 84 inches of MP produce the 3000HP at the prop (if it was all linear). Assuming the same efficiency blower one would need an 8-900 HP engine to drive the external supercharger. If one could make a much more efficient blower and get it down to 500 hp to drive the supercharger it would still require a very stout small block V-8 sitting where the pilot does........
    Then you would have the weirdness of changing all the internal stresses in the engine.

    All in theory and good fun as I left my slide rule at work..... so have fun with the blowtorches.........

  8. #8
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    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    Quote Originally Posted by Big_Jim View Post
    Yes, I talked with Dixon about this setup a few years ago, since he was actually working on the crew in 1966 for part of the season. It was Harry Volpe's idea to put the Buick engine up front to run the supercharger on the Allison. There apparently was a direct linkage from the throttle of the Allison to the Buick...so as one accelerated, the other did too...but they had a hard time syncing the rpm's up. Not sure if they didn't think of that aspect, or they tried, or something, but Dixon said that the Buick would bog down at times and couldn't turn the supercharger fast enough to give it enough boost. Not sure if it was a torque or RPM issue. They tried that setup experimentally in 1966, as well as all of 1967...when it replaced the big Aux-stage Allison.

    They gave up and went to a Griffon engine in 1968.

    PIcture is from the Newton Marine website.
    Even if they could get the rpm to sync up it seems like the Allison would be loading and unloading all the time, especially in rough water. I could see that being an issue if the blower stayed at a more constant RPM compared to what the big motor was doing.

  9. #9
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    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    Jim Hall ran a snowmobile mill on his Chaparral sport-racing car to pump the air out from under it
    for down-force reasons..

    There was an experimental Do 217 that ran a 3rd [big]engine in the fuselage to provide hi-alt boost..

    What about a light & compact turbo-shaft mill to drive an aux' charger?

    Or 'piggy-back' it via a fluid drive/ torque converter?

    Kind of a reverse turbo-compound type deal..
    Last edited by J.A.W.; 05-15-2013 at 07:57 PM.

  10. #10

    Default Re: Question for the engine guys: Merlin/Griffon Boost Engine??

    That was my thought, does the 'boost' drive have to be reciprocating?

    Snidely

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