ORIGINAL: the Wasp
the G and S use the same insides, but different cranks, the G has a lighter Case,
how about looking into a 91 Heli Engine, they should turn more pitch than a 91 Plane Engine,,
or you could buy a Towers or Jet Muffler for your K&B to increase power,
or you could buy an OS 70 Heli Engine,,
or you could buy a 91 Heli Engine and a Tuned Pipe,,
or you could buy a K&B 100
or an OS 75AX,
or two OS Hyper 50 Heli Engines,
or raise you Nitro percentage
Okay, maybe you missed a few things.. first off, I'm not looking to spend $250+ for an engine. Heli engines need high nitro, plane engines do not.
The K&B is not worth putting a tuned pipe on because most tuned pipes don't start making power until 14,000rpm which is 2,000rpm higher than I've been able to get this engine to turn up to. I've gotten 12,200rpm with the 11x7 which is way too small. The Sportster does not like 15% nitro or any higher. Its quite happy on 5-10% nitro.
Anything over a .90/.91 is going to require a prop bigger than 13" to run happily of which I just cannot do. Pretty much limited to the .60-.90 range.
ORIGINAL: AMB
An other thought the ST 90 with a Davis diesel head will turn a 16x8 or 15x9 that much blade areas is a huge increase in thrust and might achieve the speed you want
plus a lot less fuel consumption martin
As I said at the top of the thread.... 13" props or smaller. I do not have the space to turn a prop any bigger. As it is, the engine is shimmed up 5/8" to accommodate the 13" APC props I've been using therefore, Diesel is out. Also, I do not want to have to make my own diesel or order it. I want to stick with my homemade 5% nitro glow fuel.
ORIGINAL: Phoenixangel
The S is a heavier engine, it has a big case and needs a bigger mount. But they are very good engines. I do not know if they are better but they are good.
The TT PRO is a proven brand with a lot of history, you do pay a bit for it tho.
I have all 3 brands mentioned. I am a fan of ST but not a fanboy, If you run them side by side, the ST are CLOSE but not the same, and it is enough you notice right away. Either the OS or TT will normally have more power.
The ST are different to tune and need a longer break in.
They have a fat low end and that almost always needs tweaked several times during break in. All of that being said, The G90 is more then good enough to accomplish your goal. You will be happy with it.
What I had seen about the G90 and the S90K engines is RPM - the S90's will turn better RPM's than the G90 - namely the G90 seems similar to the K&B sportsters in respect to being lower RPM engines requiring bigger props yet. I found a used S90K for $50 and another new one for $85. These were the Italian-made Tigres, not the chinese imports. Also, I havent ran a ringed engine before. Anything different breaking one in vs. an AAC engine like my sportster? Slobbery rich/almost 4-stroking for an hour before attempting to throttle the engine...?