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Engine basics => Engine set up tips => Topic started by: Chris Wilson on February 21, 2011, 04:06:48 PM

Title: MVVS 49 Akrobat exhaust.
Post by: Chris Wilson on February 21, 2011, 04:06:48 PM
Hi all,
just looking at my MVVS 49 stunt engine and was wondering about the standard side exhaust canister and if I could do better.

These engines are capable of rotating their upper cylinders around to any 90º angle and at the moment it is indeed a side exhaust.

But I have the chance to put a new cylinder and liner in it and so regain the rear exhaust configuration, now MVVS do make an exhaust stub and a mini pipe for the MVVS 51 but I don't know if this would suit the 49 or even if it is still available and anyway this is a slip on setup that could be prone to leakage down the track. Their quarter wave mini pipe seems to gain power even without the use of a long pylon racer style header pipe and has a very unusual sound.

So, I am asking if anyone knows of a source of rear exhaust stubs and exhausts for this engine? (Maybe something like a RO Jett exhaust header pipe if the bolt hole configuration could be made to suit or even a full length tuned pipe.)

Thanks in advance.
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Balsa Butcher on February 21, 2011, 05:05:53 PM
If you are looking for headers first I'd check with Randy Smith to see if he has any in stock. They can also be found at Mac's Products. The .49 is not listed but the 40R is, PN 3472. I believe they are interchangeable but you might confirm that before ordering.  8)
Title: Re: MVVS 49 Akrobat exhaust.
Post by: RandySmith on February 21, 2011, 07:06:56 PM
Hi all,
just looking at my MVVS 49 stunt engine and was wondering about the standard side exhaust canister and if I could do better.

These engines are capable of rotating their upper cylinders around to any 90º angle and at the moment it is indeed a side exhaust.

But I have the chance to put a new cylinder and liner in it and so regain the rear exhaust configuration, now MVVS do make an exhaust stub and a mini pipe for the MVVS 51 but I don't know if this would suit the 49 or even if it is still available and anyway this is a slip on setup that could be prone to leakage down the track. Their quarter wave mini pipe seems to gain power even without the use of a long pylon racer style header pipe and has a very unusual sound.

So, I am asking if anyone knows of a source of rear exhaust stubs and exhausts for this engine? (Maybe something like a RO Jett exhaust header pipe if the bolt hole configuration could be made to suit or even a full length tuned pipe.)

Thanks in advance.


Hi Chris

I have both headers and mufflers and  CF pipes for the motor, It will run very well on a CF pipe, I have setup several of them, Matter of fact I just sold my last MVVS 49 last month

Randy
Title: Re: MVVS 49 Akrobat exhaust.
Post by: fred krueger on March 03, 2011, 12:25:00 PM
Chris,

I constructed my own rear exhaust muffler for my MVVS49.  I have actually made 3 versions.  The last 2 versions used a MVVS exhaust header and a mouse can.  The last one split the header pipe and used a silicone coupler.  This has eliminated the failure at the exhaust flange.  You can see (and hear) the results at:
http://controlline.org.uk/phpBB2/viewtopic.php?t=380&highlight=

Fred
Title: Re: MVVS 49 Akrobat exhaust.
Post by: RandySmith on March 03, 2011, 01:07:10 PM
Chris,

I constructed my own rear exhaust muffler for my MVVS49.  I have actually made 3 versions.  The last 2 versions used a MVVS exhaust header and a mouse can.  The last one split the header pipe and used a silicone coupler.  This has eliminated the failure at the exhaust flange.  You can see (and hear) the results at:
http://controlline.org.uk/phpBB2/viewtopic.php?t=380&highlight=

Fred

Hi Fred

How quiet is the Can muffler you made? Have you ran it  or any others for any length of time?

regards
Randy
Title: Re: MVVS 49 Akrobat exhaust.
Post by: fred krueger on March 03, 2011, 02:39:01 PM
Randy,

I have perhaps 10 flights on the muffler before Winter set in.  I did the engine break-in (1 to 2 hours) with the previous (identical) muffler with no noticeable degradation of the muffler.  However, the header failed near the mounting flange after a couple flights.  I then made another, identical unit with the header separated from the muffler with a silicone tube (like a tuned pipe setup).  I think that cured the problem.

Not having a sound pressure meter I can only give you a relative noise level.  I think it is slightly louder than a Retro 60, which is fairly quiet.  During the break-in period, I posted a video of a bench run of this engine.  There was considerable interest in that, so I posted the first full pattern as well.  You can hear the engine run pretty well during the pattern:
http://www.youtube.com/watch?v=RdwM-eU5tuE

Fred
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Norvaldo on October 08, 2011, 06:42:34 PM
Maybe you guys can help out the guy on 'the other' (Stuka forum).
http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=367929&mesg_id=367929&page=

Most answers to him are babble about Diesels and vibrations...

Title: Re: MVVS 49 Akrobat exhaust.
Post by: Balsa Butcher on October 09, 2011, 11:47:08 AM
I've tried to no avail. ::)
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Norvaldo on October 09, 2011, 11:52:21 AM
You may need to login..
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Balsa Butcher on October 09, 2011, 01:31:02 PM
No, they have been posted. I think he is looking more for attention than advice.  :-\
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Norvaldo on October 09, 2011, 01:34:53 PM
Ahh.. Ok..
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Chris Wilson on October 09, 2011, 04:00:22 PM
I think he is looking more for attention than advice.  :-\

I would have to agree with that. :)
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Bill Morell on October 09, 2011, 05:49:24 PM
No doubt in my mind. He did this same thing a few years ago when he was supposedly building something else. I think he called it the "Bamboo Bomber". After a few hundred questions he faded away.
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Norvaldo on October 10, 2011, 10:38:34 AM
I should have noticed he was veird.
Power enough for a 36" model?
LOL
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Chris Wilson on October 10, 2011, 05:36:02 PM
I should have noticed he was veird.
Power enough for a 36" model?
LOL
I was assuming that was a typo mistake and really should have been a "63" model.
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Balsa Butcher on October 10, 2011, 06:11:24 PM
...that needs a custom fuel tank 2.5" long by 1" deep by 2.5" wide and after re-reading the post, planned design has a 36" fuselage length, 55" wingspan. Don't know a standard tank couldn't be made to work. ::)
Title: Re: MVVS 49 Akrobat exhaust.
Post by: Chris Wilson on October 10, 2011, 06:14:25 PM
...that needs a custom fuel tank 2.5" long by 1" deep by 2.5" wide..... ::)
Perfectly fine for a free flight model!