Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

[AAFO_WSagar]

Re: Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

I worked for Dwight for a number of years, I just carried on....

Mike, you and Dwight are legendary.. Thank you for checking in!

Your input here helps feed the core fire of support for this! the (THE WORLDS FASTEST MOTORSPORT NATIONAL CHAMPIONSHIP AIR RACING)

THANK YOU!

[Race5]

Re: Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

For those wondering, Doc does not have a tube motor in Miss A. They did move the oil cooler to a spray bar only heat exchanger arrangement. Still a Merlin rod setup but it has all the good transport motor parts.

[mitchcarley]

Re: Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

Thank you all! Ditto Wayne. This has been great learning AND awesome to see MissA updates, with this knowledge!

[440_Magnum]

Re: Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

I noticed that there may be a confusion of "Docs" in an earlier post:

Will be interesting if Doc went to this level of 'tweek'...man! Thank you guys.

Is clearly referring to Doctor Brent Hisey, owner/pilot of Miss America and speculating on what he will show up with this year.

Doc is the one that pioneered the tube motor back in the 1960s. It was used on unlimited hydroplanes as well. I believe the first Mustang raced with a tube motor was Chuck Lyford's Bardahl Special. Later, both Mike Nixon and Mike Barrow adopted the technology as well. Rick Shanholtzer, who builds the motors for Miss America, does not build tube motors. All of his race motors still utilize the aftercooler.

"Doc" in this context is referring to the late Dwight Thorn, often called "The Doctor" or "Doc," the pioneering engine builder who built engines for Dago Red, Strega, Voodoo at one point, and I have no idea how many others between the 1960s and the 2000s. A creative genius, who as stated pioneered the use of ADI and a tube to take the boost higher on Merlins, and also developed the use of Allison connecting rods in the Merlin to let the bottom-end survive that kind of boost.

[mitchcarley]

Re: Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

440_Magnum - you are 100% correct, yet, as I was asking & stating - I understood and knew of the reply intent and info. re: Dwight. I thankfully had the chance to speak briefly to him in the pits '90s as a fan - thanking him for his dedication. I was always dumb-founded that the GM Rods were a cross-over solution...unbelievable. I spent quite a but of time with Lefty as a friend in Lakeway TX and we mentioned that fact a few times to each other...again unreal. Thank you again all for this education. m

[RichH]

Re: Tube Motor? ...please explain in 3RD Grader terms...Merlin / Allison?

Its mostly done for Merlins, I'm not sure if its been done for a Griffon or Allison.

Yes... the "tube" mod has been done on a Griffon. Here it is on a spare PM motor:





As far as Allisons... that is a whole 'nother story. The Allisons weren't given much development beyond being a single-stage engine, relying on turbocharging for any further augmentation. The late G series Allisons did have two-stage supercharging, but the second stage was added as a cobbled-together afterthought and not nearly as efficient as the Merlin's arrangement. The Allison's induction system was also far behind the Merlin's with regards to reliably being able to handle higher MAP coming from the supercharger. Efforts to incorporate induction improvements demonstrated through Merlin engine development were blatantly refused by Allison.