That engine will pull a 72 ounce 680 sq inch airplane with ease, through the pattern no less - I know, I ran mine on an overweight ARF Score. Not enough for a 530" sq? 

Header muffler, RSM 12x6 2 blade prop. Not ideal but I only use that plane as a test bed. If I were going to put it into a proper stunter I'd use a tuned pipe, 12" bolly 3 blade to start with. It is a torque motor, not high revver.  Randy has pipes and headers that will work, probably header mufflers as well. FAI or low nitro fuel.The stock muffler is difficult to mount due to its straight header design. Plane would be at least 630" squares. It needs that size of airframe minimum to accommodate its 13 plus ounce weight. 

Hi Charles,Ditto what Pete said, My .49 pulled a porky 64oz shark like a .40 in a ringmaster lol.Personally I'd put this engine in a serious stunt ship and find something more compact for your stiletto project. At around 530 squares 1 would have to assume that a .40-.46 should handle it easily. (And be easier to accomodate)Cheers, Rob..

Rob,

Thanks for the reply.

If you take a look at the drawing of the Original Stiletto, you can see that the span is quite small for the size/length of the fuselage. The model wasn't designed to do stunts.

My enlarged model has to keep most of the original design in tact, otherwise there's no purpose in building the thing based on the original designer's efforts.

At 57" the wing is really different in proportion to the model's original wing. I'll probably settle in at around 570 to 590 sq's. I'll see what the span and cord is at that number, and Post it. The fuse is drawn at 43.5" in length an swallows the engine in it's belly.

At the moment, I'm fine tuning my drawings for the drive line.

CB

Wasn't this originally a C/L Speed ship? Are you going to mount the engine aft w/ a prop shaft?

Douglas,

Yes, that's correct. Do you remember the model?

Someone posted a link, to the 1970 article, in a Thread. I apologize for not remembering who was kind enough to take the time to do this?

Yes again. I'm mounting the engine aft with a prop shaft. I know, I have a bit of work ahead of me.

However, and I'll quote a line from a movie, "I'm not a trout." 

There is an abundance of Threads on this subject matter, actually the model I'm building. I've been running my ideas in Threads. Gotten plenty of input and feedback. Input that has helped me make decisions. Thank you all!

Thanks for the response.

CB

Header muffler, RSM 12x6 2 blade prop. Not ideal but I only use that plane as a test bed. If I were going to put it into a proper stunter I'd use a tuned pipe, 12" bolly 3 blade to start with. It is a torque motor, not high revver.  Randy has pipes and headers that will work, probably header mufflers as well. FAI or low nitro fuel.The stock muffler is difficult to mount due to its straight header design. Plane would be at least 630" squares. It needs that size of airframe minimum to accommodate its 13 plus ounce weight. 

Pete,
        I have this exact engine also and don't envisage a problem with getting a steel tank under that pipe.
Do you see the height off the bearers as an issue here?

I am sorely tempted to place a saw cut right through the header pipe and placing a silicon joiner there to prevent possible cracking down by the mounting flange.
If this course is adopted then you can angle the pipe away from the tank that bit more also!

By the way, the rear exhaust 'pipe' should not add to the power of this engine as its state of tune kicks in at 13 000 rpm and it  simply goes along for the ride as a very lightweight canister that happens to follow a time worn design pattern of all MVVS pipes.

Chris and Pete,

I could eliminate the pipe. Just cut it off as suggested by Pete.  Nothing hard about that. This would provide extra room. Clamps and a drain hose out the back.

CB

That was Chris that suggested cutting off the pipe. I suggested an alternative. 

Chris,

I have no problem with removing the pipe.

What did you suggest?

CB

Chris,

I have no problem with removing the pipe.

What did you suggest?

CB

I suggested that IF your tank fouls the underside of the standard Akrobat pipe the you could simply saw cut the header through, place a silicon joiner there and get more of an angle away from the tank thereby giving you more clearance. All this is with the entire original pipe system used and simply angled.

Note to self, I must measure what the clearance is now but at a glance it seems sufficient and if not then a custom made flatter and smaller tank less than1" high is easy enough to make. And since these engines are VERY fuel efficient they do not need anywhere near the tank room that you would expect.

If you have the "Akrobat" (stunt) version of the .49, it will pull a 650 sq. in. stunter with ease.  Mine is powering a modified Kolesnikov KA-10 (heavy at 65oz).  It currently swings a Thunder Tiger 12.5x5.5 prop using 5% Nitro, 20% oil.  It runs a nice 4-2 break with around 8K launch rpm.  The engine is set up RE with a home-made muffler.http://www.youtube.com/user/pampa9m?feature=mhee#p/u/16/RdwM-eU5tuEFred 

Fred,

I have the engine in the photo.

CB

Fred,

Is this you flying that model?

http://www.youtube.com/user/pampa9m?feature=mhee#p/u/16/RdwM-eU5tuE

CB

CB,

Yes.  That's me flying.  Bill Smith is the other person in the video.
We are very fortunate to have this flying site until Honda Aviation decides to built their sales facility.  Then we'll have to do some serious searching.

BTW, my RE muffler uses a riser header from MVVS.  This provides plenty of room for tank adjustment.  I'm sure Randy's header is very similar.

Fred

CB,

Here's a photo from an ACLN article on the MVVS .49 Akrobat.  The engine, MVVS header pipe and muffler were sold by Just Engines a few years ago.  If you need dimensions, I can post the rise distance.  MVVS no longer makes the engine or accessories, however, as other folks stated, you could check with MACS or Randy Smith for a suitable header pipe.

Fred

Chris,

My pipe goes right through the bloody wing. That'll leave a mark. 

So, Fred's offering could help me with that.

I think I should purchase one of those pipes.

Parts? There's a MVVS rep that hangs out at RCU. Don't know what Country he works out of?

CB

Chris,

My pipe goes right through the bloody wing. That'll leave a mark.  

So, Fred's offering could help me with that.

I think I should purchase one of those pipes.

Parts? There's a MVVS rep that hangs out at RCU. Don't know what Country he works out of?

CB

Charles,
             there are quite a few MVVS reps over at RCU, Dar Zeelon (Israel) , Pe´Reivers (Netherlands) and Jaka (Finland, I think) - just log on over there and contact them.

As to that standard spray bar not lining up with the tank, one of my 49's is set up for side mounting and so has an alloy venturi with the spray bar mounted through that and well above the standard position, so no problem with height there. In fact I see that having the bar out board as a good thing.

Another one has the crank case drilled (notice the little circle just underneath the standard bar on the intake stub) and has the spray bar going through there - this gives a slightly better position for tank alignment. This one is for an invert mount.

And the last one, the MVVS 51 with the rear intake, actually needs the bearers carved away to make tank room when invert mounting it.

So none of them are going to have the pipe interfering with the tank.

But I personally do not like the standard peripheral jet system for stunt use (meat for another topic) but who says that the spray bar MUST align itself with the fuel feed in all cases?
The engine likes it where it likes it and you will get quite a variation of where the tank needs to be between engine brands, their mounting orientation and model types.

If the exhaust still troubles you then Just Engines (last time I spoke to them) has the header riser system in stock but no canister mufflers, Brian Eather here in Oz has carbon tuned pipes (if that takes your fancy), the MVVS factory and their reps have the rear exhaust adaptor (part number 3260) or I am sure that our host here, Randy,  can help out with a riser.

Some years ago I flew a couple of OD Vanity PA airplanes at 540 squares with Fox stunt 35 and had plenty power. 

Ok, I have measured the clearance under the standard Akrobat pipe with my MVVS 49 that is modified with a straight through Enya spray-bar going through the bald circular dimple on the venturi stack.

A normal 1" high tank fits perfectly in the distance between the bearers and the pipe with about 1/32" to spare on the tanks front edge when jammed right up against the exhaust flange, and this is with the feed pipe centralised on the spray bar.

Chris,

Thanks for offering that info. I may just rotate the inner sleeve to a side exhaust application and be done with it.

An option.

Thanks again,

CB

Probably off topic, but I run my MVVS 49 as a diesel (Davies Diesel conversion, not the original MVVS diesel setup). It is an absolute stump puller, so if you have any problems with lack of power, go diesel. The exhaust can be quite small in size and still works reasonably well.
Can anyone tell me what the Akrobat liner is timed at? I haven't a clue what my liner is?

Thanks,

Andrew.

Chris,

What upper barrel?!! What is that?

I haven't taken the thing apart yet, but I was just expecting to see a sleeve. Are you referring to the "head?"

Thanks for the heads up. Sorry I need more info. 

CB
 

Hi again (Christmas break intruded, sorry for the delay),
                                                                                        upper barrel, same as 99% of two stroke motorcycles. They have a lower casting that houses the crankshaft and its attendant bearings and a completely separate casting that houses the liner and piston.

The liner and upper barrel must be rotated as a pair otherwise the ports will not line up and the engine, although hilarious to contemplate, will not run at all.

I did mention all of this previously and quite extensively in your drive line thread.

Mate, you sound like you need a build buddy much more than this forum - perhaps you could team up with some one, join a club or simply visit a hobby shop as its going to be far more informative and expressive.

Cheers.