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Super Tigre G-90 With A Pipe
I have a brand new ST G-90 that I plan to put a pipe on. It is a Macs Muffled Tuned Pipe for a 10cc engine (yea a bit small for this motor) and I'm going to use a Macs 2900 header (for a G-60 and G-75 - yea a bit small here as well). The header and pipe aren't ideal for this motor but I'm not looking for every ounce of power as it will be going in a small plane (New Ultra Stick 40). I've started a thread on the plane in the ARF section if you are interested in following this insanity.
Breaking this motor in on a Zinger Pro 13x6 and it seems pretty freaking strong on the stock muffler. I'm looking for a touch of speed and good vertical (no 3D stuff) out of this plane and don't want to lean to far in either direction and would like to keep the pitch above 6" for decent speed. The size of the plane limits me to no more than a 13" prop I would think and would like to run a 12" for clearance. What would you guys recommend prop-wise for this motor on a 10cc pipe? I'm trying to avoid buying all kinds of props to test with. Right now I have a Zinger Pro 12x8, 13x6, 13x8 and a 13x7 Evolution ($1.99 hard to pass up). I'd like to stay with wood if I can to keep the weight down up front but am willing to run whatever prop that works well. The Master Airscrew 3 blade 12x8 has come to mind but I don't know if that would be too much or not. Maybe a MAS Scimitar 12x8 wood. From what I have read about this motor, it looks like I need to keep the RPMs in the 11,000 range. |
RE: Super Tigre G-90 With A Pipe
The first thing to do is pick one of your props, I used a 13-7 Zinger on a 90 pattern plane, muffler baffle removed, and test back to back with your tuned set up and the stock set up. The tuned one might hurt because it is too small. I like wood props and almost only run them, but an APC 12-8,9 would probably be the screamer.
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RE: Super Tigre G-90 With A Pipe
ORIGINAL: TFF The first thing to do is pick one of your props, I used a 13-7 Zinger on a 90 pattern plane, muffler baffle removed I was going to run all of the above mentioned props with the stock muffler setup first to get a base line. I can't imagine the non-optimal sized pipe would hurt it. The inside diameter of the header pipe is larger than the stock muffler setup and the pipe exit is larger than the muffler exit. I think it will be fine. I probably won't cut that much off the header though before it hits the sweet spot. |
RE: Super Tigre G-90 With A Pipe
The baffle removal is easy. Stick a screw driver in the end and drive it forward. Then roll it up with a pair of needle nose through the header opening, and pull it out.
13x7 or 13x8 would be my choice of props. David |
RE: Super Tigre G-90 With A Pipe
ry this link for Billington's review and results: F:\COMO\SuperTigre G90 Product Review.mht
I have the S90 and love it. Good luck |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: spaceworm ry this link for Billington's review and results: F:\COMO\SuperTigre G90 Product Review.mht |
RE: Super Tigre G-90 With A Pipe
Sorry 'bout that, picked wrong file: Here is the URL: http://www.supertigre.com/engines/supg0235-man.html
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RE: Super Tigre G-90 With A Pipe
ORIGINAL: spaceworm Sorry 'bout that, picked wrong file: Here is the URL: http://www.supertigre.com/engines/supg0235-man.html Thanks! |
RE: Super Tigre G-90 With A Pipe
OK, got some prop numbers.
Ritch's Brew 5% Nitro, 11/11 castor/syn blend oil Temps were about 50 degrees. Motor had about 36 ounces of fuel through it when the tests were run. Stock muffler and stock Super Tigre plug: Zinger Pro 13x6 - 11,500 Zinger Pro 12x8 - 11,100 Zinger Pro 13x8 - 10,400 APC 12x10 - 10,400 Uncut Macs 2900 header and 10cc (for a .60-.75 motor) muffled tune pipe with stock Super Tigre plug: Zinger Pro 13x8 - 11,500 APC 12x10 - 11,500 I didn't test the other props as they weren't going to be enough prop I thought. I'm not sure if cutting the header will give me any gains since this is a rather short pipe for a .90 size motor but next time I'm going to cut a half inch off and see what that gets me. But an 1100RPM increase by just bolting the header and pipe is about what I expected. The 12x10 at 12,000rpm gives about 12lbs of thrust which should be just right for my 6lb model! I think the APC 12x10 is going to be the prop I run but I'm going to buy a wood MAS Scimitar 13x8 and try that one next. I was surprised how well the G-90 pulled the 12x10. I'll post more numbers as I get them. How do these numbers compare? |
RE: Super Tigre G-90 With A Pipe
webra .90P5 with webra pipe and no nitro apc 12x12 11500rpm
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RE: Super Tigre G-90 With A Pipe
ORIGINAL: s�rpet webra .90P5 with webra pipe and no nitro apc 12x12 11500rpm |
RE: Super Tigre G-90 With A Pipe
I think you can get best overall performance with 12" props with 8-10" pitch spinning at least 12000 rpm. It wont take long to find the best prop/pipe combo. Just get the pipe surge at 80% throttle on the ground. If you damage APCs too easily then try a plastic MA scimitar, they perform about the same, handle prop strikes better, and are half the price.
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RE: Super Tigre G-90 With A Pipe
With a few modifications I was able to get 13500 from my ST90 with a 11 x 12 APC prop
http://www.rcuniverse.com/forum/m_8086613/tm.htm |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: brjensen71 With a few modifications I was able to get 13500 from my ST90 with a 11 x 12 APC prop http://www.rcuniverse.com/forum/m_8086613/tm.htm Are there currently any OS carburetors that will fit an ST G-90? I seem to be able to tune the transitions better on an OS carb while running a pipe. |
RE: Super Tigre G-90 With A Pipe
Tuned the header length a bit today. The sweet spot seemed to occur after cutting about 1.5" off the header. 3/4" first, 1/2" the second time and the 1/4" the last cut. It only got maybe 100rpm the last cut if that. Left it alone right there
Ritch's brew 5% 11/11 castor/synthetic. Motor has about 48 ounces through it so I still got a ways to go on breaking it in. APC 12x10 > 11,900 with a pinch into 12,100 or so Zinger Pro 13x8 > 11,900 I'm going to run the 12x10 as I need the ground clearance. This engine idles happily at 2400RPM and can even go down to 2200 but not as reliably. Near instant throttle response. Transition after letting it sit on half throttle for 15-20 seconds is a little sloppy as all of my Super Tigres on a pipe seem to be. Tuning the low end until it does a lean bog on a throttle blip and then richen it up a bit. All in all a nice engine for about $120 after Tower's discounts. |
RE: Super Tigre G-90 With A Pipe
The instructions say that you can run a prop as small as an 11x8 without encountering a problem with this engine. I was thinking that one of the old long stroke pattern props would probably be the best for lots of speed with a tuned pipe. If you had a 15cc sized tuned pipe, I would go with a 12x7 or 8. However, since you are going to run a 10cc sized pipe, I would drop down to an 11x11 or 12 sized prop. Don't forget to install a head shim or extra head gasket in order to reduce the compression. If you don't, you'll go through glow plugs like someone goes through popcorn at a movie theater. Good luck and come back to this thread with the results/findings of your experiment.
Ed Cregger |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: NM2K The instructions say that you can run a prop as small as an 11x8 without encountering a problem with this engine. I was thinking that one of the old long stroke pattern props would probably be the best for lots of speed with a tuned pipe. If you had a 15cc sized tuned pipe, I would go with a 12x7 or 8. However, since you are going to run a 10cc sized pipe, I would drop down to an 11x11 or 12 sized prop. Don't forget to install a head shim or extra head gasket in order to reduce the compression. If you don't, you'll go through glow plugs like someone goes through popcorn at a movie theater. Good luck and come back to this thread with the results/findings of your experiment. Ed Cregger Where can one procure head shims for this G-90? I usually run 15% nitro fuels and I thought about running a head shim on this engine to allow me to run the higher nitro fuel. I really don't want to carry two fuels to the field. |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: SpinnerRow ORIGINAL: NM2K The instructions say that you can run a prop as small as an 11x8 without encountering a problem with this engine. I was thinking that one of the old long stroke pattern props would probably be the best for lots of speed with a tuned pipe. If you had a 15cc sized tuned pipe, I would go with a 12x7 or 8. However, since you are going to run a 10cc sized pipe, I would drop down to an 11x11 or 12 sized prop. Don't forget to install a head shim or extra head gasket in order to reduce the compression. If you don't, you'll go through glow plugs like someone goes through popcorn at a movie theater. Good luck and come back to this thread with the results/findings of your experiment. Ed Cregger Where can one procure head shims for this G-90? I usually run 15% nitro fuels and I thought about running a head shim on this engine to allow me to run the higher nitro fuel. I really don't want to carry two fuels to the field. Back in the old days, I'd pick up the phone and call World Engines, but you knew that too. Today, I'd give Tony Stillman of Radio South a call. If he has a spare moment, he could probably point you in the right direction. He may even have them in stock himself. Anyone else? Ed Cregger |
RE: Super Tigre G-90 With A Pipe
Tried a wood Master AirScrew Scimitar 13x8 and that is my favorite prop on this engine so far. Throttle response is insane and the engine would spin that prop 11,700-11,800.
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RE: Super Tigre G-90 With A Pipe
Here is a video for you guys. At about 54 seconds in, I let it sit at part throttle for a bit and then nail it WOT. There is a slight hesitation there for a couple of seconds with smoke pouring out the back. This is the rich transition that I seem to experience with all of my Supertigre engines. Not sure how to tune that out. My OS engines don't have this problem. When I put the tach up, i richened it up a few hundred RPM as it was sagging when I would do a quick pinch of the line. The throttle response with this MAS 13x8 is real nice. The heavier APC 12x10 doesn't have this kind of snap to it. I like this prop enough that I made a set of landing gear for my Ultra Stick last night that is 1.5" taller than stock so that I can run this prop. The Zinger Pro 13x8 gives me close to 12,000RPM but I think I'm going to stick with the Scimitar and maybe put 1/4" or so back into the pipe length. The engine seemed smoother with the extra length.
Opinions? |
RE: Super Tigre G-90 With A Pipe
Nice results! A slightly longer pipeheader is always a good idea. I have had better succes with OS-F plugs on my 90 or larger twostrokes. It can clean up the midrange slightly and give more explosive throttle response too. 22% oil is actually too much as 15-18% is more than enough. Too much oil in the fuel gives more adjusting problems, rich midranges and more risk for deadsticks.
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RE: Super Tigre G-90 With A Pipe
Could I just order a gasket set from Tower and put an extra head gasket in it? The price is right at $1.49 !
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RE: Super Tigre G-90 With A Pipe
Yes, if the engine does not responds so well to adjusting the main needle, or sounds rough on wot, then the compression probably is too high and would be better with an extra head shim.
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RE: Super Tigre G-90 With A Pipe
After the engine was mounted up on plane, I found the high speed needle valve was just about worthless. I had a 13x8 Master Airscrew Scimitar on it and it was turning 11,500 or so and struggle to get that. It was running lean and no amount of high speed needle adjustment would fix it. So I decided to try a Zinger Pro 13x6 and it responded with 12,600 coming up on the pipe and running super rich. The needle valve was useful again. I had to turn it in almost two turns to get it to lean out but it was no longer running lean. Motor was running strong with good throttle response. Is the pipe too short for the 13x8? Any of you pipe gurus care to explain why this is happening?
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RE: Super Tigre G-90 With A Pipe
I have follwed this thread from the start but I didn't make any comments on it untill now, Your probley not going to like what I have to say, but here goes. At one time I to tried to use a 60-75 pipe on a ST K-90 I ordered the wrong one by mistake. I had two of the same planes both using the St-90 engines one was the K and one the S series The S series I had the correct size pipe on and it ran like gangbusters, I didn't have any lag or run up problems using a 13x8 MA prop, now the other pipe set up was nothing but trouble I couldn't get the turns out of it, it would get hot if I tried. I know it was the pipe doing it cause I changed setups and got within 100 RPM's of the other engine and things worked out good. So I bit the bullet and bought the correct set up and solved all of my running issues.
I know the G-90 is more of a torquer than either the S or the K series engine are and your not going to see the RPM's I did when using that size of prop, but I still think the wrong pipe may be adding to some if not all of your problems. Normally when the HSN won't adjust it not getting enough tank pressure, but why it would change with a smaller prop is strange, maybe the extra RPM's is supplying just enough to operate that prop???? |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: SpinnerRow After the engine was mounted up on plane, I found the high speed needle valve was just about worthless. I had a 13x8 Master Airscrew Scimitar on it and it was turning 11,500 or so and struggle to get that. It was running lean and no amount of high speed needle adjustment would fix it. So I decided to try a Zinger Pro 13x6 and it responded with 12,600 coming up on the pipe and running super rich. The needle valve was useful again. I had to turn it in almost two turns to get it to lean out but it was no longer running lean. Motor was running strong with good throttle response. Is the pipe too short for the 13x8? Any of you pipe gurus care to explain why this is happening? Too small pipe volume or pipes with too restrictive internal or of wrong design can give very much problem for twostrokes running behaviour and performance. When it comes to twostroke muffler and pipe an slightly too big wvolumes is always better than slightly too small. Now from your description of the engine running better with the smaller sized prop my conclusion is that the tuned lenght on this pipe is simply too short. ST90 should be able to turn anything in between 13x6 to 15x6 and you really should not need to adjust the pipe lenght if it from the start was setup long enough to handle the largest prop 15x6. With a long enough setuped pipe system you only need to adjust the needles slightly if changing the prop size to a slightly smaller or larger size. A too short pipe lenght or too large a prop. for the tuned lenght will not allow the engine to get on the pipe and you lean and lean the main needle until it goes too lean and stops. A slightly too long tuned lenght for the prop used is actually very good for sport use and makes the needle adjustments much easier and gives you more linear throttle response to fly the Ultra Stick much better and the plugs last much longer. A good piped system for everyday sport use should give about 800-1000rpm more than stock muffler for any prop. in the range. If it is not happening then the pipe lenght, volume or something else is wrong. |
RE: Super Tigre G-90 With A Pipe
I flew the plane today with the 13x6. It is turning too many RPMs I think - 12,600-12,700. I'm going to buy another header and lengthen it 3/4" and that should set me up good for 11,500 with a 13x8 which is what I want to run. The plane flew well but with RPM comes vibration and I have too much of that on this small of a plane. It will shake it to pieces. Motor sounds sick on the pipe though. I'll post some video later of me flying it.
I may have to get the bigger pipe if I can't get it tuned correctly but I think I can get it figured out with what I have. I don't want to spend $100 more on a new setup right now. |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: SpinnerRow I flew the plane today with the 13x6. It is turning too many RPMs I think - 12,600-12,700. I'm going to buy another header and lengthen it 3/4'' and that should set me up good for 11,500 with a 13x8 which is what I want to run. The plane flew well but with RPM comes vibration and I have too much of that on this small of a plane. It will shake it to pieces. Motor sounds sick on the pipe though. I'll post some video later of me flying it. I may have to get the bigger pipe if I can't get it tuned correctly but I think I can get it figured out with what I have. I don't want to spend $100 more on a new setup right now. If the Super Tigre G90 was a "real" .90, that is, developed from the start as a .90 and with a larger crankcase to begin with, then I might think that the 13x8 prop would be appropriate. But, since it is merely a puffed up G.60, I'm not that optimistic about its ability to do well with the extra bit of pitch over a 13x6. Of course, you could have it pulling a Super Sportster .40 and the lack of drag might not challenge the engine enough to make it work hard at pulling that much pitch. It all depends, I suppose. I'm sticking me neck out with this bit o' speculation, boys. (smile) Ed Cregger |
RE: Super Tigre G-90 With A Pipe
One thing to note is this motor picked up 1000+ RPM over the stock muffer just bolting the full length header and pipe to it. The "correct" header is 1/8" bigger in diameter and the "correct" pipe is 2" longer. I'm trying to keep the RPMs reasonable between 10,500 and 11,500. Whatever prop will get me in that range (APC 12x10/12, Scimitar 13x8 or a Scimitar 14x6 will I believe) is what I will use. The gear on the plane is tall enough for the 14 incher if I want to go that way. I'm not looking for max power out of this combo as I don't need it. The sound of this motor running on a pipe is cool though. I love the sound!
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RE: Super Tigre G-90 With A Pipe
ORIGINAL: SpinnerRow One thing to note is this motor picked up 1000+ RPM over the stock muffer just bolting the full length header and pipe to it. The ''correct'' header is 1/8'' bigger in diameter and the ''correct'' pipe is 2'' longer. I'm trying to keep the RPMs reasonable between 10,500 and 11,500. Whatever prop will get me in that range (APC 12x10/12, Scimitar 13x8 or a Scimitar 14x6 will I believe) is what I will use. The gear on the plane is tall enough for the 14 incher if I want to go that way. I'm not looking for max power out of this combo as I don't need it. The sound of this motor running on a pipe is cool though. I love the sound! Duke Fox said that his .74 Eagle IV couldn't really handle anything larger than a 12x7 and I know that the Fox .74 could easily dust the britches of an ST G90. I'm not putting down your opinion, or your efforts. Playing with pipes and props is all part of the fun of R/C. Please keep us informed of your results. I won't argue with your figures, once presented. Ed Cregger |
RE: Super Tigre G-90 With A Pipe
I have never in my life seen a 74 fox Eagle that was even in the same league with a G-90 ST engine, An S or K series was another total ball game they would stomp a fox 74 in the durt big time. No replacement for cubic inches. Been there and tried it myself, maybe you have a secret to getting something from a 74 but I never did find it out and nobody else in this area did either.
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RE: Super Tigre G-90 With A Pipe
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RE: Super Tigre G-90 With A Pipe
Sounds nice! looks like a lot of fun...
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RE: Super Tigre G-90 With A Pipe
ORIGINAL: NM2K ORIGINAL: SpinnerRow One thing to note is this motor picked up 1000+ RPM over the stock muffer just bolting the full length header and pipe to it. The ''correct'' header is 1/8'' bigger in diameter and the ''correct'' pipe is 2'' longer. I'm trying to keep the RPMs reasonable between 10,500 and 11,500. Whatever prop will get me in that range (APC 12x10/12, Scimitar 13x8 or a Scimitar 14x6 will I believe) is what I will use. The gear on the plane is tall enough for the 14 incher if I want to go that way. I'm not looking for max power out of this combo as I don't need it. The sound of this motor running on a pipe is cool though. I love the sound! Duke Fox said that his .74 Eagle IV couldn't really handle anything larger than a 12x7 and I know that the Fox .74 could easily dust the britches of an ST G90. I'm not putting down your opinion, or your efforts. Playing with pipes and props is all part of the fun of R/C. Please keep us informed of your results. I won't argue with your figures, once presented. Ed Cregger |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: Cyberwolf I have never in my life seen a 74 fox Eagle that was even in the same league with a G-90 ST engine, An S or K series was another total ball game they would stomp a fox 74 in the durt big time. No replacement for cubic inches. Been there and tried it myself, maybe you have a secret to getting something from a 74 but I never did find it out and nobody else in this area did either. I agree that the S or the K would at least equal the Fox .74, but I haven't seen a G90 that was anything more than a slightly glorified G60. All I can do is state my experiences. Good running Fox .74 engines were indeed hard to find, but when you did find one, it was a strong runner. Duke blew it with the .74. He had a combination that worked, but he moved on and the rest of the engines he made in that size were turkeys. I know, I had one. It would not run longer than five minutes before overheating and quitting, even when set slobbery rich. Ed Cregger |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: Cyberwolf I know the G-90 is more of a torquer than either the S or the K series engine are and your not going to see the RPM's I did when using that size of prop, but I still think the wrong pipe may be adding to some if not all of your problems. Normally when the HSN won't adjust it not getting enough tank pressure, but why it would change with a smaller prop is strange, maybe the extra RPM's is supplying just enough to operate that prop???? |
RE: Super Tigre G-90 With A Pipe
OK, I give up trying to tune this thing with the small pipe. I took it flying yesterday and black goo was on the tail after the first flight. I hope I haven't killed the motor already.
As a refresher - I'm running a full length uncut 2900 header on this thing with a 10cc pipe designed for a 60-75. I think this setup would be fine if I wanted to run more than 12,500RPM but I'm trying to keep it below 12,000 for vibration's sake. A 13x6 at 12,600-700 seems to work fine but it about vibrates the motor off the front of the plane. I think this is the RPM would the G-90 really enjoys running because once it hops on the pipe at 12,500 or so, it is sick sounding. But... 11,500 RPM is my target but I can't get a prop/pipe combo that will get me there running the 10cc pipe. With a 12x10 and the full length header, I'm getting 10,800 with a very rich tune. I pinch the fuel line and it hops on the pipe to 11,200-300 and stays there running lean and the needle valve is ineffective even after richening the mixture. Pull the throttle back and hit it again and it hops up to 10,400-500 - pig rich, pinch the line it hops on the pipe and goes lean. AHHHHH!!! So... I bow http://smileys.on-my-web.com/reposit...ct/bow-004.gif to the wisdom previously presented in this thread and hope I haven't killed the motor (might have). I might buy a new piston, liner and ring anyway and do some port smoothing before I put it back to together. Thanks to all of those that tried to warn me despite my hardheadedness and stupidity! |
RE: Super Tigre G-90 With A Pipe
Just put in an order for the big pipe and header. I'll post what I find. I may find that I need a new piston, ring and liner!
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RE: Super Tigre G-90 With A Pipe
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ORIGINAL: SpinnerRow OK, I give up trying to tune this thing with the small pipe. I took it flying yesterday and black goo was on the tail after the first flight. I hope I haven't killed the motor already. As a refresher - I'm running a full length uncut 2900 header on this thing with a 10cc pipe designed for a 60-75. I think this setup would be fine if I wanted to run more than 12,500RPM but I'm trying to keep it below 12,000 for vibration's sake. A 13x6 at 12,600-700 seems to work fine but it about vibrates the motor off the front of the plane. I think this is the RPM would the G-90 really enjoys running because once it hops on the pipe at 12,500 or so, it is sick sounding. But... 11,500 RPM is my target but I can't get a prop/pipe combo that will get me there running the 10cc pipe. With a 12x10 and the full length header, I'm getting 10,800 with a very rich tune. I pinch the fuel line and it hops on the pipe to 11,200-300 and stays there running lean and the needle valve is ineffective even after richening the mixture. Pull the throttle back and hit it again and it hops up to 10,400-500 - pig rich, pinch the line it hops on the pipe and goes lean. AHHHHH!!! So... I bow http://smileys.on-my-web.com/reposit...ct/bow-004.gif to the wisdom previously presented in this thread and hope I haven't killed the motor (might have). I might buy a new piston, liner and ring anyway and do some port smoothing before I put it back to together. Thanks to all of those that tried to warn me despite my hardheadedness and stupidity! Wipe some of the oil off on your finger and hold up to the sunlight. If there is a metallic look, something is wearing.... I did something similar with a 60 size Big Stick. I ran a Jett 90L on it and while it would pull the plane around like a rag doll I went back with a .75 size engine. I just thought it flew better/longer on the same amount of fuel. I learned that a draggy airframe can only fly so fast and decided to save the 90L for a proper model. Good Luck with your project.:D |
RE: Super Tigre G-90 With A Pipe
ORIGINAL: Broken Wings It's perfectly normal for a piped engine's exhaust to be pretty dark or even black, especially if the fuel contains castor oil. The heat of the pipe cooks the oil. However there should be no metal particles. Wipe some of the oil off on your finger and hold up to the sunlight. If there is a metallic look, something is wearing.... I did something similar with a 60 size Big Stick. I ran a Jett 90L on it and while it would pull the plane around like a rag doll I went back with a .75 size engine. I just thought it flew better/longer on the same amount of fuel. I learned that a draggy airframe can only fly so fast and decided to save the 90L for a proper model. Good Luck with your project.:D Some day I will own one of Dubb's motors. He produces some works of art for sure. |
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