thanks nick

Ill get bthe new readings to you as soon as I can.
Moving house this weekend.[&:]

Nick

I have never heard of an OS A5 plug??
I am going to try the OS 8 four stroke plug in the ST90.

Do you have any details of the A5?

Thanks
Rob

http://www2.towerhobbies.com/cgi-bin...&I=LXCB29&P=ML

HaveBlu

12600 with a 12x8 APC.
Are you using stock muffler ?
Plug?
Fuel?

I have an ultrathrust muffler on and getting 12300 peak.

Thanks for the info

Rob

thanks w8ye

Current G90, with stock muffler, OS A8 plug

Wildcat 15%, 18% oil, 80/20 syn/castor
13/6 TF power point
13,200 peak, 12,900 to fly
Have run about 9 tanks thru engine, 4 on test stand
82 degrees, 80% humidity


Big difference when I switched from St plug to the OS #8.

Wonder how much gain one could expect if you removed the baffle, mine is loose anyway and rattles.
Engine is still breaking in and seems to get better with every tankful. the 13/6 may be too small a prop if rpm keeps increasing.

Failed to mention that I have also cut off the manifold pipe about 1/2" so it does not stick so far into the muffler - should help reduce restriction further. The baffle is removed, I plan to fly next week with the above changes-will post results.

What is the current wisdom on glow plug heat range for the ST 90.

Bill

Bill-not sure about the current wisdom-but one of guys I fly with has about 30 years of using ST engines-he helped me with my G90-I was suing the ST glow plug on breakin and starting to have trouble. We switched to the OS #8, which he uses in all his ST engines, and bingo-like a completely engine, even before it was starting to break in. That is only plug he uses in his ST G90s.

Thanks.

Bill

The Super Tiger engines seem to be able to take abuse and keep flying. Many engines will not tollerate abuse. I was very interested in trying the tuned pipe on this engine. Have any of you experimented with the pipe on this engine?

Does anyone have rpm numbers for three blade props? I have an application that needs a three blade prop.

Bill

I had the same results putting a OS 8 in my gms 47 it upped the reliability 100%.

Bill I have seen a guy fly one with a 12X8 MS three blade on a 60 size Mustang with good results. He had a pitts muffler on but don't know if it made more power with pitts muffler or not. It reved up really well in the air and had good speed.

My impression so far with the Super Tiger 90 is good. I don't think it can outpower all the other 90 size engines out there but it certainly can hold its own. It is cheap and built well and should hold up for the rest of your life with occasional bearing changes. Mine runs like a top with a 13X6. I want to try a tuned pipe but haven't gotten around to it yet.

I have a new G90, Bison pitts muffler, Zinger 14x6 prop, and 6 - 8 tanks of gas through it. I broke in with a 13x6 APC. I can only get 9000 RPM on 15% omega. Any thoughts on why the RPMs are low. I plugged one of the outlet tubes, made no difference in performance

Dave

Dave,

Have you tried lower nitro fuel? I ran my ST 90 on 5% at around 10K with an APC 14~8. Your engine might not be fully broken in yet either.

Terry in LP

I dont have any 5% fuel.  Did try the stock muffler this week end and was able to max out @ 9,700 RPM.  The pitts must have  too much back pressure. </p>

 How much additional shim is recommended to run 15%??</p>

Dave</p>

</p>

</p>

Where can one get a Magnum 108 carb if one should desire one?

I have the impression that this engine is better off at a bit higher RPMs and thus with propellers
like 13x6 and 13x7, while 14's are a bit too heavy for almost any .90 engine unless it is a long
stroke engine, which ST seems not to be, and the torque thus is not the best this engine
could deliver, what ever the nitro % is. If you could get this engine at 11000 and even up
to near 12000 RPMs then you see the "ST-miracle".

What do you think about those "ideas" ?

Surely I compare with my OS.91 and I do no think that ST.90 is more powerfull
to be loaded with heavier propeller than the ones I use for OS.91. On those
OS.91FX the experiments with APC 14x6 show good results, and they get
a bit better after  damaged the tip of the 14x6 propeller and balance it</p>

down to 13x6 ...

Cheers,
Nick</p>

Good luck

Nick,I don't think there will be any miracleby trying to rev this engine to more than 11K. The G-90 has a 60 size casemachined to accept a 90 size sleeve. The boost and tranfer port passagesare tight (small) and the crank gas passage is 60 size as well.My G-90 is a great sport engine that iseasy on fuel, but it is no rever like the .61 ST's

I sold mine, headache gone !!!

Nick,

If you are looking for a high reving 90, get a ducted fan/marine engine or a Jett.The Super Tigre 90 is a torquer that does better turning larger or steeper pitched props at around 10,000 rpm. In Mike Billinton's review in MANDec '96he stated that "...the G90 appears to benefit more than usual from its narrow transfer passage and high gas-transfer velocity (which usually follows from boring out a given crankcase); this favors low-rpm operation." He also ranked it#2 in his "Comparative Torque" list (oz.-in./lb. and oz.-in./cc) of the top 12 engines tested. Only surpassed by the 3W B120 twin 114cc gas engine!Third was the Webra 120. The ST turned an APC 12~12 at 10,900 piped and a15~6 at 10,000+! I used to run an S90K at 10,000+ with a 14~8! Pulled 9 pounds (wet) of draggy plane (Joss Stick) with authority.

It's not all about high revs or even long strokes.

Terry in LP

I have a GS-45 and a G-51. I plan to buy a G-90 soon. I should have snapped one up when Tower put them on sale for $99! Still kicking myself about that one.