We're putting together our first 'non-trainer' plane, which is Top Flite's P-51D Gold Edition Mustang. (It's not the giant ed., it's the one with a 65" wingspan." It came with an OS .61FX engine. We're thinking, however, about upgrading engine size - perhaps an OS.91FX. On the other hand, we're wondering if we should go up to a 4 stroke, and get a 90 4 stroke, for example. Only thing is $200's the limit. With this range, it appears that we could go with an OS .91FX 2 cycle or we could go with a 'Magnum' 4 stroke 91 engine. Or, we could simply stay with the .61.

Any recommendations / advice would be greatly appreciated.

Thanks,
Joe

Go for the Magnum or TT 91. You'll never look back.

Enjoy

Jim

If funds permit, I too would go with a 4-stroke. Take your pick of brands: OS, Saito, Magnum (or YS if that check from Ed McMahan comes in the mail). The larger prop will look better, and the sound will make a believer of you. If you stick with a 2-stroke, a .91 will let you swing a bigger prop too, and give you more power than you could ever need. It comes down to how much you can justify spending. Consider the cost of a pitts style muffler to match the 2-stroke, and the price is similar to the cost of a reasonably priced 4-stroke. The Super Tigre .75 is another good choice if you like the 2-strokes as you can use the Top-Flite in cowl muffler/header (another 20 for muffler and 15 for header). If you use the Super Tigre .90, you can use the Bisson or Slimline pitts.

Pilgrim

Thanks for all the advice. I think I'm going to go with the Magnum 4 stroke 91. One question. Are the Magnums well made? I know that OS has a good rep. for reliable engines.

Thanks again!

Joe

Joe:

The Magnum IS the OS for a much more reasonable price.

Bill.

Thanks again for the advice. I just learned that I could get the TF "inside" muffler for my FX .61. This would be nice b/c it's a hidden muffler. My question is if this 'hidden' muffler performs as well as an external muffler.

The TF in-cowl muffler should perform fine, but may be a little louder than the stock 2-stroke canister muffler. If you opt for the in-cowl setup, you might take some time to port-match the header to the exhaust outlet of the engine. I have a Super Tigre .75 and the TF header for same, and the header did not match the outlet for the engine exhaust port. I spent some time with the Dremel and a carbide bit to match the opening to prevent excessive exhaust obstruction (better performance).

Pilgrim

It looks like this thread was some years ago,, But we are thinking of buying 4 of the TF Gold edition P-51D's for some formation flying, any suggestions on if the 61 motor is enough to not just fly it but have great performance as well, a couple of the guys have 61's already and want to use them in this formation build we are doing, so regardless of what the size plane it looks like we are going to use the 61 size motors, we just want to use the Mustang as the plane.

SO, we are either going for the TF 60 size or the Great planes 40 size and put 60's in that. they say the 60 is too much motor for the GP Mustang, I'm not sure if that is accurate, we all fly over powered models now, so we have been debaiting this for quite sometime so we would like to finally make a decision and get BUILDING... so any advice will be great..
thanks

Today, everyone are using the 60 style 91's made from an original 61 size case in the old 60 size war birds.

Edited first 9 to a 6

90 style 90's ?? Never heard of that before,, LOL ,

so people are putting a 90 size in a 60 size plane I take it,, which is what we think,, The 60 size in a 40 sized plane should be okay, but some people are saying no, I guess I'm just trying to find someone who has actually used a 60 in the GP 40 sized Mustang before I comit 3 other people to the purchase of everything.

By your message it looks like the 60 would be under powered for the 60 size plane and that was exactly what I was looking for. Thank you.

I once put a Saito 100 in a GP 40 size Extra...Wicked uplines, will go up forever...and ever...and ever!!!

Great flying plane, you guys ought to try it.

MR G

Very few people put 60's in 60 size war birds any more. Even in the two strokes. The OS 125AX would be great if you could arrange the muffler situation.

A 91 four stoke is the minimum four stroke. Likely candidates are Saito 100 and 125.