HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 06, 2005, 05:48 AM
Registered User
MrPropJet's Avatar
Australia
Joined Jun 2004
139 Posts
tuned pipe on a .90 size engine

Has anyone run a tuned pipe on a .90 size engine, if so , do you think it's worthwhile going to such a set up or is a waste of time, mine in particular is a G90 Supertigre with a mac's pipe, I havent fitted the pipe yet as the engine still needs to be broken in and as it is the header is to shallow for a proper fit to my plane , but if I get any favourable comments regarding this sort of set up , I will find a way to fit it together
thanks
Roger Z.
MrPropJet is offline Find More Posts by MrPropJet
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 06, 2005, 12:18 PM
BAKO
Bako's Avatar
Tbilisi, Georgia
Joined Jul 2004
772 Posts
btw tuned pipes, like resonator tubes give u extra 10-15% of power, depending on engine. it works better on 2stoke engines, where rpm is higher, and muffler isn't free flow, like 4 stokes have.
Bako is offline Find More Posts by Bako
Reply With Quote
Old Jan 06, 2005, 02:38 PM
Registered User
pda4you's Avatar
USA, TX, Trophy Club
Joined May 2002
14,521 Posts
Quote:
Originally Posted by majic12
Has anyone run a tuned pipe on a .90 size engine, if so , do you think it's worthwhile going to such a set up or is a waste of time, mine in particular is a G90 Supertigre with a mac's pipe, I havent fitted the pipe yet as the engine still needs to be broken in and as it is the header is to shallow for a proper fit to my plane , but if I get any favourable comments regarding this sort of set up , I will find a way to fit it together
thanks
Roger Z.
It is best if you break them in with the pipe - you want the engine speed at break in to be about your top RPM on the pipe. You can also use a smaller prop to attain this.

ABC engines properly timed can benefit greatly from the use of a tuned pipe. You can easily acheive (with engines timed for their use) a great deal more power 15% is easy to get.

That is the good news. Here is the bad, they are a pain to setup and they work the engines very hard. They add weight also. You will go through plugs regularly. But they are quiet, sound great, and keep some of the mess off the front of the plane, plus the added power.

You can do one of two things - get the Ultrathrust tuned mufflers, they get you more power or do what I started to do rather than mess with pipes. Just get a larger motor with more power. With the bored out engines, you can often find a larger motor with the same weight as the smaller ones!

Mike
pda4you is offline Find More Posts by pda4you
RCG Plus Member
Reply With Quote
Old Jan 06, 2005, 02:53 PM
BAKO
Bako's Avatar
Tbilisi, Georgia
Joined Jul 2004
772 Posts
never brake engine on top rpm. !!!
pda4you let me know any manual, where it is written to brake engine in top rpm.
Bako is offline Find More Posts by Bako
Reply With Quote
Old Jan 06, 2005, 03:06 PM
Registered User
pda4you's Avatar
USA, TX, Trophy Club
Joined May 2002
14,521 Posts
Sure - Dubb Jett and Clarence Lee

Do you know how ABC engines work? You want an ABC (this is ABC we are talking about, not ringed or 4 stroke) engine to reach the same temp so the materials will expand properly. If an ABC engine is run too rich the brass cylinder will be too tight a fit, and prematurely wear the piston out.

Note that I said the RPM or speed must be up - not the work. So you use a smaller prop so that the 400 rpms that you do run it rich (in break-in only) still attains the same top run RPM's of the engine - this is the only way to do it right.

Talk to Dubb - a guy that knows engines (he makes some of the top performing 2 stroke model engines in the world).

http://www.jettengineering.com/tech/breakin.html

How about that?
pda4you is offline Find More Posts by pda4you
RCG Plus Member
Last edited by pda4you; Jan 06, 2005 at 03:09 PM.
Reply With Quote
Old Jan 06, 2005, 06:51 PM
Registered User
MrPropJet's Avatar
Australia
Joined Jun 2004
139 Posts
I actually did intend to fit a larger engine, an OS 1.08 FSR 2 stroke, it has more peak rpm and it is rated at 3hp , not 2.5 like the ST, unfortunately the 1.08 was to long to fit in the nose, and I didnt want to try extensive modifications to the nose to fit it, so hence I ended up getting the Supertigre .90 2 stroke....pitty I think the OS would have made the f4 Phantom scream... might try the mod at a later date, I have a feeling the G90 will dissapoint me!

btw I omitted to mention that the g90 is a ringed engine, and I didnt think running it at max rpm was a good idea straight out of the box!.. now I have to find out if the information above would be applicable to a ringed engine , eg breaking it in with the pipe at max rpm but smaller diameter prop
MrPropJet is offline Find More Posts by MrPropJet
Reply With Quote
Old Jan 06, 2005, 07:00 PM
BAKO
Bako's Avatar
Tbilisi, Georgia
Joined Jul 2004
772 Posts
soo. I don't understand your method. when abc engine is too hot, piston wears the cilinder, cause due to big temperature, metal is ovesizeing.
Bako is offline Find More Posts by Bako
Reply With Quote
Old Jan 06, 2005, 07:54 PM
Registered User
pda4you's Avatar
USA, TX, Trophy Club
Joined May 2002
14,521 Posts
Quote:
Originally Posted by Bako
soo. I don't understand your method. when abc engine is too hot, piston wears the cilinder, cause due to big temperature, metal is ovesizeing.
The engine is not hot - it is being run rich, but with a prop that is smaller, so it has the advantage of not working as hard, being run slightly rich, and having proper component heat to assure the engine is not wearing harshly.

ABC engines must run at temp when being broken in. It keeps them nice and tight. You would probably go nuts to watch me break in an new ABC engine -another key is getting them to temp ASAP. You start (that very first time) at idle, but advance to full throttle as soon as you can! You go to full throttle, peak the rpms (yep that is right!) and once peaked (don't let it sag for more than just a second) you richen by 300-400 rpms (tach necessary) and let it run 30 seconds. Then the motor must cool completely. You do this cycle doing longer and longer runs. Depending on how tight the engine is you may need to do this a while. Once it will hold peak without sagging, it is ready to fly. I run my ABC engines at 100-200 (max) rich rpm (from peak).

Try it on your next motor - you will be surprised how well it works. By the way the OS and TT sport engines are much less critical on break in. They are of average power anyway. The Rossi's and MVVS will take a bit more care. The Nelson and Jett really need attention to this matter. But they will turn 4-8K higher than sport engines anyway.

Refer to RCM Magazine as Clarence Lee covers the topic of ABC engine break in very regularly. I only have one issue (one where I did some photography for a model and plans featured) but he covers it again and again.

Majic12 - Please don't use the ABC method of break in for a ringed engine. They must be broken in very differently than an ABC engine. They also tend to gain less power from piping, as they are normally timed a bit more conservitavely.

Ringed must be run rich - slobbering rich, just on the verge of 4 stroke. You just want to take them to that 2 stroke, 4 stroke sound change. Then run them (they take a long time - several gallons of fuel!) But I usually only run 5-10 tanks on the stand, then do the rest in the air. Once again - it will tell you it is done, when it holds a peak setting without sagging. Then you richen the mix 200-300 rpm (ringed - half that for ABC).

Try that ST .90 you might be surprised by the power.

Mike
pda4you is offline Find More Posts by pda4you
RCG Plus Member
Last edited by pda4you; Jan 06, 2005 at 07:57 PM.
Reply With Quote
Old Jan 07, 2005, 03:57 AM
Registered User
Tony Oliver's Avatar
North-East England
Joined Mar 2002
3,402 Posts
If you have any doubt about which method to use, ask the manufacturer (it's usually in the instructions anyway).

The differences between cast iron pistons, ringed pistons and ABC setups is as Mike says and it's uselass and often damaging to use the procedure for other than the specific recommendations for type.

After all, the final outcome looked for is to get a perfect running fit at the speed the engine is to run at when in use. Most systems will respond initially to give the polishing effect but the fit is the main requirement.
Tony Oliver is offline Find More Posts by Tony Oliver
Reply With Quote
Old Jan 07, 2005, 04:37 AM
Registered User
MrPropJet's Avatar
Australia
Joined Jun 2004
139 Posts
I have got the instructions on running in the engine , so I will follow them then worry about the pipe....It would be handy to find a dyno to measure the performance, apart from that I can only gauge the performance with my tacho, but I would rather be able to graph a torque curve for it but dont know how with out a dyno!!
MrPropJet is offline Find More Posts by MrPropJet
Reply With Quote
Old Jan 07, 2005, 06:09 AM
BAKO
Bako's Avatar
Tbilisi, Georgia
Joined Jul 2004
772 Posts
I had broke in MDS18, MDS40, OS40 LA, with succes. as i told. maby u'r right.
but i like 4 stoke brake ins . it's whole science.
Bako is offline Find More Posts by Bako
Reply With Quote
Old Jan 09, 2005, 01:48 AM
Registered User
Dave Barrow's Avatar
United States, KY, Covington
Joined Feb 2003
1,502 Posts
I had an Enforcer with a piped Super Tigre .90. (language removed by moderator) . It was a porker too, 12+ lbs. I would break it in on a bench with the stock muffler if it was me. There are different ways to break in ABC and ringed engines. Never get an ABC engine slobbering rich, you'll ruin it. Once you have several tanks through it, put the pipe on and tune it, then put it in your plane and go. Use your tach and you'll see the difference.
Dave Barrow is offline Find More Posts by Dave Barrow
Last edited by tonyo; Jan 09, 2005 at 08:32 AM. Reason: inappropriate language
Reply With Quote
Old Jan 09, 2005, 06:16 AM
Registered User
MrPropJet's Avatar
Australia
Joined Jun 2004
139 Posts
well this is looking better and better, hopefully this combo will make my F4 really motivate.
MrPropJet is offline Find More Posts by MrPropJet
Reply With Quote
Old Jan 09, 2005, 10:57 AM
Registered User
Dave Barrow's Avatar
United States, KY, Covington
Joined Feb 2003
1,502 Posts
What brand of pipe are you using? Macs pipes are the best that I have used. A 90 on a pipe is pretty loud, the muffled pipes are nice, since they reduce the volume. Make sure you follow Macs tuning instructions. You can find them on their website.
www.macspro.com
Dave Barrow is offline Find More Posts by Dave Barrow
Reply With Quote
Old Jan 09, 2005, 12:40 PM
Registered User
Bill Glover's Avatar
United Kingdom, Bracknell
Joined Nov 2000
12,058 Posts
I ran both the Super Tigre 90 and 75 piped, using an ST pipe on the 75 and a Hattori on the 90. Neither ever blew a plug in use! As already posted, get the engine well broken in first and set the pipe up according to the instructions. If in doubt leave the manifold a little long.
Bill Glover is online now Find More Posts by Bill Glover
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion what size fuel tank to use on a 90 sized engine? spitfire123 Engines 3 May 09, 2006 10:36 AM