Hi guys,

After going up from small planes to big I've now started doing R/C Combat flying here in the UK. The rules state that the motor must be 0.30 or below and have a tuned pipe or silencer no more than 8" long. So what would you recommend as the most powerful sub 30 size 2 stroke??? I have used a Super Tigre 29, an Enya 29 and a Leo 25 all on standard silencers but want a bit more grunt than they can give. Fuel used is 10% ProSynth. Before I pipe them is it worth starting with a better engine?

Any recommendations gratefully received!

Andy

Try a Webra Speed .28 with a Mousse can muffler. Here are the instructions:

Mousse Can Mufflers got their start in Unlimited Competition Fun Fly, and accomplish two things.
1. They are lighter than either a stock muffler or a tuned pipe.
2. They provide a pipe-like power boost, but without the peak in the power curve. This was very important to a Fun Flyer when even a one click change in throttle made a large difference and you didn't want all that power coming on at once.

The size of the can is relatively unimportant. If fact, nothing about these cans is critical. I'm using a White Rain (about 1.5" x 4") for my OS.32. An FDS can works well, too, but you might get some funny looks from the sales clerk. A .40 size engine will probably take a standard mousse can (about 1.5" x 6"). Also purchase the header for your engine and a 12" length of brass tubing (about 1/4" for the small engine, and 5/16-3/8" or so for the .40's). I know this sounds small, but you're creating a pressure canister that will boost the mix like a pipe would. You will also need a package of JB Weld, available at Wal-Mart. Now for the assembly:

1. Remove the nozzle of the can and release all the pressure. You might want to do this outside.
2. Using a drill and a sanding drum on a Dremel, open the nozzle end of the can to just slightly under your header diameter. Use needle nose pliers to crimp the edges of the hole outward so the fit on the header is tight.
3. In the center of the bottom end, drill a tight hole to fit the brass tubing you chose.
4. Scuff the can, header, and tube roughly with sandpaper to create a good surface to glue to.
5. Cut about 1"-1.5" of brass tubing and insert it into the hole about 1/4"-1/2".
6. Mix the JB Weld and apply liberally around the tube/can joint. Let stand for 24 hours, no less, and DON'T move it during that time.
7. Slide the header about 1/2" into the other end and apply the JB Weld. Make sure you get a good fillet here. Let dry following the above instructions.
8. Determine what quadrant of your can will be straight down when the engine is mounted, and drill a 1/16" hole at the rear edge for drainage.
9. Support the can with a fuselage pipe mount as you normally would a pipe.

That's it, sounds hard, but is really easy, and I think you'll like the results.

Dr.1

I agree with using a Webra engine, but I would use one that is currently produced. As you are using it in combat, you want an engine that has parts currently available. The 25 is the current engine size.

My mistake, I thought they'd brought the Speed .28 back into production. They're all a Speed .28 crankcase (which was the original in this size range) with the stroke and bore modified to acheive the .25, .28, and .32. The Speed .32 is a screamer, and will turn an APC 10-4 at over 14.2 grand.

Dr.1

The only small Webra engines today are the 25 32 and 36 and all are in the same basic crankcase.

.36??? Don't tell me they did away with the powerhouse Speed .40! AAARRRGGGHHH!!! I'll hoard my two.

Dr.1

Don't worry, the 40, 50, and 55 are in the next larger crankcase size and are current.

Thanks guys, Weston UK do a West 25 which is a heavily reworked Webra 25. It's just a bit pricey but turns a 9x5 at 15krpm more on a pipe!!

I'll have a look into the mousse can muffler too, but time is an issue!

IMHO the most powerfull sub 30 motor for combat would be the MVVS 28 set up for the black Mini pipe.

What kind of combat do you fly? The most popular combat class in the UK is 12th scale and the max motor size is 25. See http://www.geocities.com/CapeCanaveral/Runway/9790/ for diary dates and rules. This is the only one that I know of that is flown nationally.

jd,

At the moment I'm doing SPAD combat, using Draco airframes from www.spadtothebone.com. I've changed the design slightly and it flies very well. I did my first combat compitition a couple of weeks back and managed to win! So I'm well up for doing some more now.

After a lot of thought and discussion, I've ordered the MVVS 26 combat engine from JE with the mini-pipe. Webra 25s are just too expensive as is the West 25. And I haven't got time to make mousse can mufflers right now, maybe over the winter but I've got 4 SPADs to build in 3 weeks!! From the specs the engine looks light and powerful, but the with the nature of combat I didn't want to spend too much!

Andy

A Jett .30 would be the hottest, but also the spendiest.

www.jettengineering.com

You may want to email on the length of the motor, I'm not sure if it is under your 8" rule.

Living in the U.K. as you do I would give Just Engines a call and ask them to send me a MVVS .26 Combat engine (4,2 GFS/R - RC Combat). Plenty of power for your purposes and not to expensive either.

/Red B.

Red, thats the motor I've ordered now! See 3 posts up

looking forward to running it [8D]