Hey folks,

I am putting together a Aero Works 50cc Yak with a DA-50 and am looking for advice about the different muffler options. I would like something that is quieter than the Slimline pitts muffler - I guess that would be either a cannister muffler or a tuned pipe. Desert Aircraft has cannister mufflers by KS (both rear and front outlet) and MTW (front outlet), and has a tuned pipe by KS. The Aero Works Yak is set up with a tunnel to accept any of these options. My questions are as follows:

Among cannister mufflers, is there much difference between rear outlet and front outlet?

Will the KS tuned pipe give more power than the MTW and KS canister?

Does the tuned pipe have a narrower power band, or is it harder to tune?

Which setup gives the best transition?

Thanks for your help!
Dan

The MTW and KS cans both work very well on the 50. Front or rear exit KS cans no real difference in power. The KS 1060 will make quite a bit more power than the cannister mufflers. If set per KS/DA instructions, the transition is awesome, and not real peaky if the correct prop is used. The pipe will change the powerband of the motor, and it will like to rev the rpms up to make the power, so if you go the tuned pipe route, use a prop like a 22x8 that will let it rev on up into the powerband (using a big prop to load up the motor with a tuned pipe and you are losing what the pipe is there for). The motor can take lots of rpms no prob. Just depends on what you are looking for I guess, the cans will not add a significant amount of power over the stock DA muffler, the pipe will, but does weigh a bit more than the cans. If it was me I would go with the tuned pipe, the 50cc motors love em.

PS, you may want to consider the full length BMB tuned pipe for your 50cc, I believe DA is carrying these now and supposed to make great power as well, and a little less finicky than the KS 1060 pipes.

I am using the KS tuned pipe on my DA 50.Using the zero drop header from DA.Swinging a 22X8 NX prop at 7400 rpm.I fly at 5000 ft elevation and wanted the extra omph.This set up was easy to tune and gives great transistion.Yanks my Extreme Flight Yak at 16 lbs really well and has nice pull out from a hover.Because of the rpm's it does bark a little prop noise but the pipe is pretty mellow.Anything is better then that Slimline as they are power robbers.This was my first tuned pipe and I am very happy.

Thanks guys. I am going to ask Desert Aircraft as well and see what they say, and to see if they have the BMB pipes. Also - I am flying basically at sea level - would 22x8 still be the right prop at sea level with a tuned pipe?

If you are at sea level you can probably get away with a 22x10 or 23x8, but definitely not recommend a 24x8. I would try the 22x8 first and go from there. If you load it down too much, you take the pipe off the powerband and then the pipe is pretty much dead weight.

r

just a quick note.....

the slimline is WELL within IMAC dB limits and quiter than most glow planes.... at least according to the dB meter at a couple of IMAC contests

For that Yak I used the KS rear exhaust can and the KS 25mm drop flex header and it all installed like a glove. Mine came in at 18lbs and flew very well.

I'm on my second one using the new 3w55i on a 3W header and the same canister and all I can saw is WOW and I'm still at 18lbs

bubbagates,
Do you know the KS part numbers for what you used? Was it the 70cc canister (#86) and the #42055 header? Also, what prop have you been using with this combination? Are you going to the 3W55i because the DA-50 was not enough?

I will just add that from recent personal experience you are right to look at this very carefully. 2-stroke engines live and die by the exhaust system you put on the end of them, they are almost more important for generating power than the engine itself. I just posted these tacho numbers on my DA100 for your interest (the 100 is obviously just 2 x 50cc cylinders):

On a custom very quiet (well baffled) muffler:

brand new engine, without cooling baffles in cowl:
4650rpm on a 28x10 MZ

run in engine, without cooling baffling:
5000rpm on a 28x10 MZ
5700rpm on a 27x10 Mejlik
same rpm in the air

run in engine, with heavy cooling baffling:
5800rpm on a 27x10 Mejlik
rpm in the air seems (though has not been instrumented) 300pm+ higher, so 6100rpm+ in the air

I know that with cannisters others are getting 1000rpm more on the 27x10 than i am even now. With the tuned pipe they are getting almost 2000rpm more. So with the tuned pipe setup its like an almost whopping 50% bigger engine than I have!! (given the expo power curve)

Murri,
We make several PITTS style mufflers for the DA 50 all are lighter and customers have told us they get more power than the others. The 2 pitts versions work very well and are easy to install (2 bolts and fit behind the cyclinder)

The standard size uses a 2" can and is pretty quiet. Our larger version uses a large chamber( can) and has been tested at 95 db at 9 feet (indepently tested) One of our customers installed the large version on his ZDZ 80 and picked up 300rpm over the other brand and his db rating was 89 at 25 feet using a loud wood prop.

We can also do custom work and modification if needed

If your interested give a call.


Al Young
JTEC/RADIOWAVE
704-799-1658
[email protected]
www.jtecrc.com

PS. my son use to work for DA before coming home to finish college

Has anyoone use this muffler by Chip hyde:

http://www.chiphyde.com/html/accessories/exhausts.html

Azhar

murri

Those are the numbers for the DA50. I went with the 3W because of cost and I hear the 3W50 was a little powerhouse. When I bought the 55i it was on sale for $535.00 so I bought it and the 3W 22x10 prop. I also bought the 3W wrap-around header and it was a perfect fit on the Yak as well

The DA50 was fine at 18lbs but I like reserve power. For extreme 3D you want 16lbs or less for a DA50, at least in my opinion