Tune pipes
 

Would you use a tune pipe on a 3D plane? 94" span. I am trying to decide if I should. I took a pattern plane and enlarged it and changed a little. But I like the way the fuse is biult with a tune pipe inside it. But I dont want to build it like that if its the wrong thing to do. Any comments would be appriciated.

RE: Tune pipes
 

I guess nobody knows, or maybe its a stupid question.

RE: Tune pipes
 

I would also like to know if anyone is using a tuned pipe on a large model and how it compares to an engine using a standard muffler or a can muffler. I have a ZDZ 80 that I would like to use a tuned pipe on and am wondering if the AMT tuned pipe from RCS is the only one for that engine and how much does it improve the performance.
Jamie

RE: Tune pipes
 

Dick Hanson is the tuned pipe expert around here. Try to get in touch with him.

RE: Tune pipes
 

Generlly speaking, I don't think you would want a tuned pipe in your general 3D setup unless you are able run run a very long header section. I also looked into this a few months ago and learned that you mid range will suffer unless you have room for longer header legnth. Your top end however will peak much higher. So....if you like to huck it on the deck.....I wold go with a Canister or Standard Muffs........but if you more of a pattern guy.....they a tuned pipe may be for you.




Neo

RE: Tune pipes
 

Like this?

This is a KS full wave tuned piped set up.

RE: Tune pipes
 

I never said it couldn't be done....that it just may not be favorable in some applications. Every engine responds differntly to a pipe.




Neo

RE: Tune pipes
 

also different carbs reacte differently when a pipe is used --and different size props change the entire picture .
On my ZDZ50 n full AMT pipe - it works bet with engine stating at over 7000rpm -preferrably 7400-8000rpm - the engine is very happy with that setup but swapping props to ones which load to 7500 on the ground - the power is not nearly as good at hover -
pipes are not just another bolt on item which can be used without further adjustment
Done right - used right - big power boost on any size two stroke.
On little engines like my Evolution 1.6 - the std pipe works perfectly with any prop --provided that prop runs easily over 8000rpm on the ground .
On larger ones -it is really best to get some help from someone who has used the combo you want to use -and that is really on a case by case basis --

RE: Tune pipes
 

Now we are talking. Good info.

RE: Tune pipes
 

The AMT pipe on the ZDZ80 single is a wild combo - mine turns over 7000 on 26x10 mejzlic.
This pipe is good on the single 80 - with rpms setup to be in higher 6000range and low 7000 range .
For most applications tho -go with a 80mmx300 JMB can on extremely short header - 5-6" long for best power .
still the best power to low sound & lightweight setup going. expect mid to upper 6000rpm range on Mejzlic 26x10 -
like any of these engines -- best power is in upper 6000- to low 7000rpm range
the noise tho -especially on in cowl "mufflers?" becomes pretty awful.

RE: Tune pipes
 

Dick,

I have an EF 87" Yak with a DA-50R and KS1060 tuned pipe. I ended up needing to add an additional 5oz lead on the nose to get my balance. Do you know if the upcoming ES Composites 50cc CF pipe has been tested?

Regards,

Steve

RE: Tune pipes
 

Ed is going to run those tests -likely this weekend.

On my EFYAK -I placed all servos forward -which allows bateries -to be placeaft as desired I got mine in at 15.25 lbs easily with this setup :1-8611 running a pushrod to elevators and one pull pull 8611 to rudder .

I detest 2 (or 4) elevator servo setups - tho easy to do they are just one more "unknown" on having exact trim throughout entire elevator travel.

RE: Tune pipes
 

I too have the exact set-up as "stomper" and I have had the opportunity to fly a couple DA-50s running regular mufflers. Tuned pipe is the way to go for me. It is more power overall and the throttle response is so much better. And it also doesn't sound like you are running a chain saw in the air. I also just finished a Ultra-RC Giles 202 with a Evo 26cc and the CF tuned pipe and a header from Carl Muller. I have spoken to Ultra-RC owner Brian Hughes about this engine on this plane and for those that followed this set-up find this is the perfect combination once the engine is broken in. Tuned pipes work and to me are worth the money. Especially when going to larger gassers.

JP

RE: Tune pipes
 

Brian Roth; If you look at any production 2-stroke motorcycle, tuned pipes are standard equipment. It has to do with fact that 2 strokes are different from 4 strokes in that they take their intake charge at the same time they are expelling their exhaust. Without a pipe part of that intake charge follows the exhaust out of the combustion chamber and out the exhaust pipe. A properly sized pipe with the correct pipe/header length will reflect a pressure wave back toward the exhaust port to push back that part of the intake charge so it can take part in the combustion/power making process. The overall size of the pipe must match the displacement of the motor and the overall length of the pipe/header combination must match the desired rpm range of the motor, hence the term "tuned pipe". It is also important to note that pipes do not always produce top end power at the expense of low end pull. It is true that if the rpms drop too low the motor will go "off the pipe" . But if properly tuned, a pipe/header combo will give substantially more power across a usable rpm range than a standard muffler. As an example, in kart racing a popular class used to be Yamaha Kt-100 cc motors. Two classes using these motors were allowed, one using a pipe and one using a can muffler. The piped motors produced about 16 hp and the can motors about 12 hp with much less pull out of the corners. In summary, tuned pipes will always increase the power to weight ratio of a 2 stroke motor over a usable rpm range if you are wiling to put up with the up front cost of a pipe.

RE: Tune pipes
 

So it sounds like I need to get as much built on this plane as possible so I can weigh it to see what size engine I will need. Then I will see what is out there that will work for that engine. What do you think?

RE: Tune pipes
 

Yeah, try to get a handle on what the plane will weigh less engine then look at the different combos that are out there, either glow or gas. If your weight comes out similar to a 2meter patterm plane then run what the pattern guys run, something like an os120 w/pipe with maybe a slightly longer header for 3d/sport flying. If you want to go petrol, something that size/weight would match up good with an evo/mvvs 1.6 like Dick Hanson described.

RE: Tune pipes
 

A properly designed and built tuned muffler would be a better alternative than a pipe. A tuned muffler (not like the ones commonly sold) will improve your power by 25% and provide an "electric" powerband, that most tuned pipes are not capable of.

RE: Tune pipes
 

A properly designed muffler which is not tuned is also a very good choice -- the model of JMB I like is that type can - run on a very short header - the powerband is seamless from idle to full power.
Once you tune to a boost - there is a point --somewhre in the band which is the transfer from below resonant to resonant.
some "pipes" are extremely good at masking that point - providing th prop rpm is matched and th carb is set correctly -
The worst problem - adding large props which are used to reduce noise -
these really screw up any tuned setup and contrary to what some believe. reduce power band available.
I have used and do use all three types exhaust setups - depending on the application.
tuned pipe
tuned can
muffler only can.
of these the muffled only can is easiest to install and setup - and depending on engine /prop - far better than the so called factory in cowl devices.

RE: Tune pipes
 

ES Composites was to test the prototype 50cc CF tuned pipe. How did the tests turn out?

Steve

RE: Tune pipes
 

Hello Dick,

Many years ago, I was experimenting with large props on a piped Top Flite Contender. I cut many lengths of aluminum tubing, and used an additional silicome coupler to add this additional tubing between the header and the pipe. I found a big increase in power at lower RPMs (for a given large prop size), as I lengthened the header with these extensions.

Do you know of anyone who sells a thrust tester these days? I used to have one, but no longer (don't remember who I loaned it to). I guess I could build one with a fish scale and an engine test mount on a sliding track...

Anyway, do you know of anyone who has worked out and published the approximate header lengths for .40-.60 sized engines tuned for lower RPM operation?

RE: Tune pipes
 

No worthwhile info I know of is available .
basically --rpm on these tiny engines is in the 10000 rpm---- minimum -------range . we once did OS61 engines for pattern and the pipe setups were a real pain in the butt.
not only must you get the right length- and volume - you must maintain exhaust systm temperature/pressure to hold reasonable results
a frustrating experience.

RE: Tune pipes
 

If you install your engine with RPM meter to a car you can rather scientifically tune the pipe. Of course for safety you need a "designated driver".

RE: Tune pipes
 

Hmmm...would you elaborate a bit more? I don't follow what you mean.

Thanks!

RE: Tune pipes
 

Mount whole fuselage or motor with pipe, cowling and RPM and thermometers to the right side of a car or on top of a truck.

This simple method was used before onboard dataloggers were available to get accurate RPM / speed mapping with different pipe lenghts, propellers, fuels, head caskets etc. I have not used but as Dick wrote when .61 two strokes were THE F3A engines in 80s some serious pilots did.

I have located the bearing point on "Pendel" elevator and did some experiments with rudder amplifier tab.