I'm looking for an engine to put in my P-51. These are the first 2 I am looking at, the SuperTigre G90 and the Satio FA-91S. Here's where my confusion sets in, unless Satio is a much superior company why would it cost more then the SuperTigre for less performance. According to the SuperTigre website the G90 produces 2.5 hp, while the Satio 91 produces just 1.6 hp. What am I missing here?

It looks like the Saito is a 4-stroke and the g90 is a 2-stroke. 2-strokes cost more then 4-strokes.

Just as in cars, hp. figures don't mean much taken by themselves. The Supertigre makes that power at an rpm the Saito never sees, and the Saito probably out torques the ST. As far as superiority goes, a matter of opinion, but they don't get any better than Saito. You can turn a larger diameter prop with the 4-stroke engine (Saito) and use less fuel doing it.

I don't know which P-51 you have, but either engine will work on a .60 size plane. Some just like 2-strokes better than 4-strokes, but (and I am prejudiced here) nothing sounds better than a 4-stroke in a warbird (or any other plane, as far as that goes) I own nothing but Saitos, not counting my gasoline engines.

And generally, 4-strokes are more expensive, more moving parts and more complex.

And if the plane takes a 91 2 stroke motor, then you are going to want a 150 or 180 4 stroke motor.

We run 100 4 stokes in planes that would be talking a 60 2 stroke.

Horsepower ratings from manufacturers are like "watt ratings" from car stereo manufacturers. Buying a "200-watt" car amp made by Kraco at the swap meet might seem like a better value than paying 3 times as much for a "50-watt" amp from Kenwood, but all watts aren't created equal.

Saito engines are four-stroke power plants and they are very well made. Super Tigre engines are two-stroke power plants, and they too are very well made. Four stroke engines have more moving parts and are more expensive to manufacture. They don't produce as much power as a two-stroke engine with the same displacement, but they produce more torque and they can turn a larger propeller and they are more fuel efficient and they sound cool in the air.

While you were comparing horsepower and price, did you also happen to compare the weight of the Saito and Super Tigre engines with muffler? 2-stroke engines are normally much heavier than a four-stroke with similar displacement.

The basic comparison between 2-stroke and 4-stroke is one of horsepower versus torque. 2-stroke engines spin small propellers faster while 4-strokes turn larger propellers. If you want the most power for the least amount of money, two-strokes are the way to go. If you want great performance and a more realistic sound from your model, a four stroke might be worth the investment.

You might also need to select a particular type of engine so your plane balances on its center of gravity one way or the other. There are certain ARFs where a lot of pilots are buying large 2-stroke motors rather than 4-strokes because they need the extra weight. The planes tend to build tail heavy and the pilots go with heavier engines so they can balance the aircraft without adding lead weight to the front.

There's really no such thing as a bad engine anymore. 2-strokes are nice, 4-strokes are nice, and every engine has a niche. Your goal is to find the engine that is best designed for your particular aircraft and how you want to fly it. If you're going to fly your Miss America like a high-speed pylon racer, a good 2-stroke is probably your best choice. If you want to fly it like a scale warbird, then a 4-stroke will sound better and will give your model more realistic flight capabilities similar to the full-sized mustang.

Good luck

Thanks guys for the great replys. being new to anything isn't really fun. I have the Hanger - 9, P-51 60 Miss America. Hanger-9 used the Satio 91S in it's test flights. Just to make sure I got this right. the Satio is a 4 stroke engine tha produces more torque then the SuperTigre 2 stroke engine.

That is correct. A Saito .91 4-stroke would work while a Saito 1.00 would give you a little more power. You could also fly the P-51 Miss America with a Super Tigre .61 ABC 2-stroke engine, or select the Super Tigre .75 ringed engine for more oomph.

The 4-strokes will give nice "scale" flight characteristics and sound while the two-strokes would offer faster flight performance. The engine you select should be reflective of how you'd like to fly the plane.

with a 2 stroke engine you will want a pitts style muffler to fit in the cowl, 4 stroke stock mufflers will already fit.
I have heard alot of good things about the Tower Hobbies .75 2 stroke, may be worth looking at.

Satio 100 is the motor for that plane. And now they have the 125 wooooohoooo!

On the other hand, How new are you to all this? I you are planning to learn on this bird I have bad news! Wrong plane. IMHO

Simply the fact that you are asking these questions leaves to believe you need to leave that Mustang in the box for a while. When your ready for it, you will know enough about RC to make a good choice.