Taming Tuned Pipes

[ben_beyer]

I've never had an airplane that's had a tuned pipe set up in it, but I'm thinking of getting one. I've read a lot where people complain that the pipes seem to be too peaky. They often complain that it's too on and off and makes it hard to perform certain maneuvers. Now I've also read that one way to fix this problem is by programming in a throttle curve.

So, I've started this thread for people who are interested in tuned pipe set ups to discuss, ask questions, and learn how to tame them. I certainly don't want an airplane that feels like the engine is either at idle or full power, so what do you do to tame them a little bit and make the midrange smoother?

[rcairflr]

I hope to get some good info here, putting a Greves Tuned Pipe on DA-85

[sprice50]

DA85 on greeves or KS1090 doesn't have problems with peakiness using the stock DA double bend flex header. Consistently, the KS1090 setup has performed excellently with no peakiness. 6450rpm on first run on 28x10Mej on new motor. Getting reports of up to 6650 now.

These new pipes have the volume to avoid them being peaky.

Check out my thread DA85 / KS1090 thread at the video link below for proof and tons of info.

[ben_beyer]

But what if he's putting it into a QQ 101" Yak? I think people may need to trim off a little of the header thereby shortening it. I know one guy is having problems with the pipe being too peaky.

[sprice50]

	Quote: Originally Posted by ben_beyer
	But what if he's putting it into a QQ 101" Yak? I think people may need to trim off a little of the header thereby shortening it. I know one guy is having problems with the pipe being too peaky.

You should ask Reza what header length to run. They would know and would have tested it.

[wecoyote]

Tuned pipes are just that, "tuned" for a given rpm.
The way a tuned pipe works is to echo the end of the exhaust pulse where a bit of incoming fuel/air is coming out the exhause and push it back into the cylinder at the correct time for a given rpm which is where you get the boost. If you change the length of the pipe you are changing the echo length and it will peak at a different rpm. If you want an engine to perform at all rpm's then you do not want a tuned pipe.

[sprice50]

	Quote: Originally Posted by wecoyote
	Tuned pipes are just that, "tuned" for a given rpm. The way a tuned pipe works is to echo the end of the exhaust pulse where a bit of incoming fuel/air is coming out the exhause and push it back into the cylinder at the correct time for a given rpm which is where you get the boost. If you change the length of the pipe you are changing the echo length and it will peak at a different rpm. If you want an engine to perform at all rpm's then you do not want a tuned pipe.

I agree to a limited extent. The size of the 1090 pipe has in my experience eliminated any peakiness. I agree that shortening the header would increase peak rpm in which case a 27x10 would be better and increasing the length will increase the torque in which case a larger prop os better. However, my piped setup will destroy a stock DA85 at any RPM. I know this from flying it. Take a look at the video.

Also my buddy has a ZDZ super 80 on AMT 105 and he experiences the peakiness you discussed and more tuning issues. The answer is to use a bigger volume pipe and although peak rpm may be less, the pipe is way better suited to IMAC and 3D.

I agree a DA100 on stock muffs is a easier install on 35% at similar weight to DA85 on pipe, but the DA85 gives you the ability to fly a range of sizes from 33% on canns or stock muffs to 35% on pipes.

[flying skunks]

I have put a set of Greeves on my Torch/Kroma 180 , WOW !!

[Altavillan]

The trick is to make clamps that allow moving the canns or pipes. Usually 1/2" in or out will get rid of the peakiness. While retaining the power. These were formed around a large socket. You want the ends to come close to touching when tight to prevent colapsing the cann.

[Olli-Matti]

I have a DA50 with a KS1060 and the 1060 has the tuned length of 755mm (from the exhaust port to the beginning of the cone). It means that it is tuned for approximately 6700rpm's and I run a mejzlik 22x8 which turns @7400 rpms on the ground.

This means that I have relatively 'long' pipe setup and because of that it is not peaky at all. Well a littlebit ofcourse, but after applying throttle curve not peaky at all. So, linear throttle and insane throttle response. And the torque that the engine produces is significantly increased compared to standard 'mufler'.

And when you throw in a Krill 28% Katana you have an unbelieveable combination.

[Eagleburger]

I had rc boats and eastern MXers that had pipes and seemed to have idle and on the pipe. I didnt play with the boats for long and eventually got a KTM 400. So I can tell you you can have a pipe and smooth linear throttle. Man I loved that bike. Only better was the fourstroke that replaced it.

[ben_beyer]

So let's say you can't extend your header length, it's just play with the throttle curve and tame it down?