Author Topic: Miniature V-12  (Read 866 times)

Offline galland

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Miniature V-12
« on: September 08, 2020, 04:27:29 PM »
Having made a couple air powered radial engines I have always wanted to try a V-12. I looked at the Allison and Merlin and decided to try to get something that had a resemblance but still stay rather simple. This will be in the 1/10th. scale and around 6 inches long with about a .500 bore. It will have the bores across from each other so will need some type of blade and fork connecting rod assembly. It will not need 7 main bearings as in the originals. I went the flathead Ford way and decided one bearing every 4 cylinders.    Gary

Offline stevehuckss396

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Re: Miniature V-12
« Reply #1 on: September 08, 2020, 05:10:09 PM »
1/2 inch bore is tiny. I'll be keeping an eye on this one.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline galland

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Re: Miniature V-12
« Reply #2 on: September 09, 2020, 02:56:41 PM »
With my rods being about .215 wide at the big end there is not near enough room for 3 rows of 0-80 cap screws (.085 X 3) so I am going with this design which should be fine for an air powered engine and much less work involved. First photo shows conventional blade and fork.

Offline crueby

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Re: Miniature V-12
« Reply #3 on: September 09, 2020, 04:29:35 PM »
Interesting solution! Sort of like how the rods on a radial engine are set up with one master.    :popcorn: :popcorn: :popcorn:

Offline Johnmcc69

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Re: Miniature V-12
« Reply #4 on: September 09, 2020, 05:00:27 PM »
 :ThumbsUp:
 That's pretty slick!
How will you set up the "valving"?

 John

Offline galland

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Re: Miniature V-12
« Reply #5 on: September 09, 2020, 05:05:53 PM »
That's right Crueby. Time will tell how it works out. Another first for me is to try and make a one piece crank with a 5C collet. Here is my modified collet with maximum offset as shown with internal threads bored away. Crank will only be about 4 inches long so going to give it a try. 
Still thinking on the valving John. Am giving some thought to Chuck Fellows designs for air powered engines.

Offline Johnmcc69

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Re: Miniature V-12
« Reply #6 on: September 09, 2020, 05:29:29 PM »
Chuck used a pretty simple & effective design.

 Hope this helps:
http://www.modelenginemaker.com/index.php/topic,1275.msg37662.html#msg37662

 It may get tricky with your opposed cylinders, but I'm sure you can get it to work...

 John

Offline galland

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Re: Miniature V-12
« Reply #7 on: September 10, 2020, 02:55:43 PM »
Thanks for the info John. Chuck was quite the guy with all his ideas and designs. I miss him. Here is my roughed out block and my prop reduction drive cover. I am not going to go with separate cylinders as in the Allison and Merlin but my one piece heads will be inline with them. I do want the drive cover and some sort of supercharger housing at the rear to give it a some what resemblance. I always liked the look of all those bolts on all the covers so even though its totally unnecessary I am going to be tapping a ton of small holes.    Gary

Offline galland

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Re: Miniature V-12
« Reply #8 on: September 14, 2020, 02:32:50 PM »
The crankshaft turned out pretty well with a little lapping to get the fit I wanted with no wobble. Seems to rotate fine with my one off connecting rods. I staggered them with the swing arm going left then right through out the 6 positions.    Gary

Offline galland

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Re: Miniature V-12
« Reply #9 on: September 15, 2020, 04:05:58 PM »
This has been kind of a design it while I build it which is how I do a lot of things. I never know if what you see is what you will get till its done. I mentioned lots of small tapped screws (over 200 and counting).   Gary

Offline Admiral_dk

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Re: Miniature V-12
« Reply #10 on: September 15, 2020, 08:48:07 PM »
It looks VERY clean (lines etc.) right now  :ThumbsUp:
... but it's a LOT of screws / bolts in your design - are you sure that you need that many ?
Don't get me wrong - I do understand why more bolts can share the load and keep the engine parts flat and oil tight - but to me it looks like you doubled how many I would have thought would be the maximum  :thinking:

Best wishes

Per

Offline galland

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Re: Miniature V-12
« Reply #11 on: September 16, 2020, 03:00:39 AM »
Admiral,  You are right that I did not need all those screws. I just always liked the look of seeing them on the aircraft V-12's from the 40's. A large part of them on my engine are only 1/16th long and serve no function other than looks.    Gary

Online sco

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Re: Miniature V-12
« Reply #12 on: September 16, 2020, 07:39:42 AM »
Really like the look of this engine Gary and you are doing some great machining, can't wait to see it running!

Simon.
Ars longa, vita brevis.

Online steamer

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Re: Miniature V-12
« Reply #13 on: September 16, 2020, 11:10:37 AM »
That's coming along great!!!   I too like the look of the multitude of scale placed and sized screws!

Dave
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Damned ijjit!

Offline galland

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Re: Miniature V-12
« Reply #14 on: September 21, 2020, 08:15:06 PM »
Had not got around to making a tubing bender so gave that a try and bent up several with different radius and I think I have settled on this one. Had tried several times to see if it would run for me but had no success so went back and checked all cam ports (air powered engine) and timing and everything looked good. I am used to most of my engines running well on 1-2 thru 5-6 psi. I was pushing this 20 and over and not getting as much as a putt -putt. Finally ran it up to 30 and over and away it went. Sounded nice but sure eats the air. Will play around with it some more and then try and make a short video. Also need to do something different with my roughed out prop blades but not sure what to do.    Gary