stunthanger.com
Engine basics => Engine set up tips => Topic started by: Chris Wilson on April 14, 2011, 08:49:12 PM
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Just waiting on delivery of a MVVS 51 rear intake, rear exhaust stunt engine and was just trying to garner peoples opinions on them.
Thanks.
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I gather you mean the rear intake, rear exhaust .51? I think Jim Oliver has run one of these. You might want to email him through the forum.
Fred
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A few Aussies swear by , rather than at , them . Dallas Hanna on here being one .
Ive finally figured a intake priming tube for the H.P. 40 R.P.R. will save a few hassles.
a alum. or copper pipe to intake from outboard, to use a syringe to give correct prime.
Then its either tip the nose down , or blow tube on vent, to see fuel line is primed.
For first flick starts.
Climate would affect intake type. I got 1/4 turn differance on the neddle from top cowl
off to fitted, just useing the nose intake, for the same flight r.p.m.s
Presumably if you fly in the snow youd use this ' carb heat ',
and if you frequent the Saharah Desert , a ' cold air ' intake might be usefull.
Would also be a way to choke injun , If a stiff tube from venturie went outboard,
Putting the tounge or some other extremety over this should result in depression at the spray bar.
and permit a more conventional approach to fireing the sucker up .
How much does the 51 weigh ?
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I gather you mean the rear intake, rear exhaust .51? I think Jim Oliver has run one of these. You might want to email him through the forum.
Fred
Funnily enough I have just bought one from Jim!
And yes Mat, Dallas knows his way around a MVVS 51 very well and we are in the same club - I was just looking outside of the square so to speak for anyone else's experiences.
It seems to be a heavy (or is that spelt 'strong') engine, beautifully made and quite powerful when used with a factory pipe and Dallas has no issues with it being a rear intake .
Thanks.
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At The risk of being thrown out of Stunthanger, The MVVS 49s and 51s make superb F2b diesels.
Regards,
Andrew.
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At The risk of being thrown out of Stunthanger, The MVVS 49s and 51s make superb F2b diesels.
Regards,
Andrew.
RANDY!!! RANDY!!! Did you see that??? LL~ LL~ LL~ LL~ LL~ LL~ Steve
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I'm still looking for a '60s vintage MVVS 5.6 RISE with "stunt" timing ;D (would even consider a later vintage)
Big Bear
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At The risk of being thrown out of Stunthanger, The MVVS 49s and 51s make superb F2b diesels.
Regards,
Andrew.
Hah!! I have a MVVS 49 and 40 as diesels and the 51 and another 49 as glows.
And yes they are darn tough engines. I like the diesel except the other day I got whacked by the 49 D on the back of knuckle whilst starting it - took two weeks to really heal! Ouchy.
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Hi Steve,
Looks as though I am not the only heretic on stunthanger. Seems as though Chris is more into MVVS diesels than I am! Just because you americans can't stand the perfume of diesels........................................!!!
Best Regards,
Andrew.
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I'm still looking for a '60s vintage MVVS 5.6 RISE with "stunt" timing ;D (would even consider a later vintage)
Big Bear
Bill, I suggest that you keep a watchful eye on this site as I do remember a MVVS 5.6 stunt motor popping up before.
http://www.old-engine-model.com/index.php?stranka=glow&od=10&kolik=10&lang=en
Good luck!
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I don't know if the rear intake MVVS .51 is set-up the same (compression, timing etc.) as the .49 (8cc Akrobat). If it is, you could compare it to the setup for my .49. So far, I'm quite happy with the .49. I even have a spare engine.
http://www.youtube.com/watch?v=RdwM-eU5tuE
http://www.youtube.com/watch?v=C9kMo3mCZBM
Fred
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I don't know if the rear intake MVVS .51 is set-up the same (compression, timing etc.) as the .49 (8cc Akrobat). If it is, you could compare it to the setup for my .49. So far, I'm quite happy with the .49.
Fred
Hi Fred,
the MVVS 51 appears to have the same bore but a tad longer stroke than the 49 when my friend Dallas eyeballed the two liners side by side - the ring around the top of the liner is thicker and so the head sits up a fraction higher. And as to the timing on the 49, I have an old liner and a newer one, and the new one has trapezoid shaped transfers and a far higher placed boost port so the new ones would seem to be more aggressively timed. Setups should vary depending on which liner one has.
Head Compression from standard appears the same but lower crankcase compression would have the 51 as a bit higher due to its rear intake and thus be a more efficient pump.
And standard venturi setups are vastly different with the 49 getting a sprinkler type and the 51 a spigot.
The 51 runs a far shorter header pipe than the 49 and again 'appears' to be a more aggressive setup and the 51 that I have seen in a stunter runs very powerfully and fast whereas the 49's I have seen seem to loaf around the circle.
If what I have seen is right then the setups would have to be quite different surely.
Thanks.
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RANDY!!! RANDY!!! Did you see that??? LL~ LL~ LL~ LL~ LL~ LL~ Steve
LOl heres the problem with the "D" motors...your wife won't allow you back in the house unless you strip down and get hosed off outside, then you have to burn the clothes your wore..and no one except your flying buddy will ever ride in your car again... LL~
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LOl heres the problem with the "D" motors...your wife won't allow you back in the house unless you strip down and get hosed off outside, then you have to burn the clothes your wore..and no one except your flying buddy will ever ride in your car again... LL~
So apart from social ostracism you don't find any problems with running a diesel in stunt?
That's great news! But I must admit that I would never dieselise a MVVS 51, they are just too good as glow engine and can you imagine the prop whack it would give on the back of your knuckle?
Cheers.
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At The risk of being thrown out of Stunthanger, The MVVS 49s and 51s make superb F2b diesels.
Regards,
Andrew.
HB~> HB~> No no Andrew!! HB~> HB~> The MVVS 51 rear intake/rear exhaust makes a fine glow stunt engine, just the way the designers wanted it. Not only that, I have to agree with Randy about the 'orrible smell of the diseasils which would mean I'd have to live outside with the dog!
I've actually been using this model engine since 1995 and have been more than happy with it. A bit heavy?? No heavier than many other engine setups which have been used over the years. It's a powerful engine when used as designed, that being to run on the standard no nitro fuel with it's mini pipe exhaust. Take into account that these engines only use 90 cc of fuel for a pattern there's a weight saving there over some of the other engines.
In saying all this, these engines are now extinct so no use looking for them over the counter. They are only available from our stash as they become available in sell-offs. This engine lost sales in Australia by "problems" being found by one or two "experts" who never run them beyond the bench. The other two people in New South Wales who owned 51s during the 90s took too much notice of the "experts" and modified the engines resulting in unreliable runs. I now have one of those engines and it's now completely back to standard form ready to run. That makes 4 of them in my stable. Would I sell any of them? No, there's still too many experts here in OZ who'd wreck them for the sake of modifications because of their thoughts on how an engine should run.
HH