[sugarpops]

OK here goes, where can I find out how to tell which 4 stroke is the same as a 2 stroke, eg.

OS 70 surpass= what 2 stroke OS??

OS 48 surpass= what 2 stroke OS?? etc.etc.etc....



Thanks

[Midair]

Sugarpops:

At the risk of sticking out my neck and having it chopped off by far more knowledgeable and experienced persons than I, I have always used the general rule of thumb that says that a four stroker has about 2/3 the power of a two stroke engine. I.E.

.60 4 stroke = .45 2 stroke
.90 4 stroke = .60 2 stroke
1.20 4 stroke = .90 2 stroke etc.

Again, this is only a general rule of thumb.

Cheers,

Peter

[hifly2104]

Originally Posted by Midair

Sugarpops:

At the risk of sticking out my neck and having it chopped off by far more knowledgeable and experienced persons than I, I have always used the general rule of thumb that says that a four stroker has about 2/3 the power of a two stroke engine. I.E.

.60 4 stroke = .45 2 stroke
.90 4 stroke = .60 2 stroke
1.20 4 stroke = .90 2 stroke etc.

Again, this is only a general rule of thumb.

Cheers,

Peter

Sounds pretty close to me. What is the reason for needing to know.Most planes now tell you what size engine to use whether it be 2s 4s or a gasser

[sugarpops]

well the reason was, I have an OS 48, and an OS 70 that I got in a trade, and I have a couple of planes that I thought these would work in,

here's the planes, tell me what you think...

40 size twist- has a MDS 46
40 size bipe - has an OS 40
60 size super chipmunk ( no engine)
40-60 size Telemaster - has a magnum 45


Thanks

[hifly2104]

Well I would say the 70 would work in the telemaster or the bipe would fly the twist but that would be all The 48 size I would think you would need a plane needing a 25/35 2 stroke engine.Just checked my FS ONE sim and it shows the twist with a 72 saito so it might fly the twist well also. The point being though the three planes that the 70 will fit in already have motors . You need to try and sell these two you just got and get something for the Chipmunk.IMHO

[sugarpops]

Thanks for your input, time to decide...

[Wayne22]

The OS 70 is one of my favourite engines....It turns the Twist into a LOT of fun!!!
http://www.youtube.com/watch?v=-68FjfbXQCU
It is pretty versitile - I've used it in 90 size planes as well. It does as well or better than a 60 2 stroke in most planes.

The 48 would be a good replacement for any normal 40 size two strokes.... in fact my little 26 four strokes will swing a 10 x 6 prop as fast as a plain bearing 40! A lot depends on the condition of your engines.. if the rings are worn, for example, you will not get nearly the power out of them...

[JKovats]

The os 4 stroke would fly any of those planes. Put it in them all. Then you decide if it flies them "the way you want it to". That becomes a personal decision that only you can make. Four strokes handle props different too. You will have to play with props a bit on each plane before you judge performance.

I have a sig something extra that I had a saito 65 on. Flew great. Had a saito 80 come available. It had the same footprint as the 65 so I put that in. Did it fly better. No! Same pilot. Now, unlimited vertical. Did I really need that?? Only if that's what I wanted to do. Swings a bigger prop so does the same stuff as the 65, just at a slower engine rpm.

If the chipmunk is the Carl Goldberg Super chipmunk or close to it then a 90 four stroke or a 60 two stroke would be suitable.

I have an OS 90 4 stroke in mine.

Ed S

[Guest]

Originally Posted by sugarpops

well the reason was, I have an OS 48, and an OS 70 that I got in a trade, and I have a couple of planes that I thought these would work in,

here's the planes, tell me what you think...

40 size twist- has a MDS 46
40 size bipe - has an OS 40
60 size super chipmunk ( no engine)
40-60 size Telemaster - has a magnum 45


Thanks

Do the planes with the engines fly well enough to suit you? If so why putz around with swapping out motors. I have seen the 72 inch Telemaster fly well on a good .35 remember it’s supposed to be a slow primary trainer. As to the Super Chip I also know of more than one flyer who powered it with a .60 four stroke and it flew quite scale like in all maneuvers. However if you are looking for unscale like verticals and giant loops as well as barn burner passes then you will need a larger engine. I think the 70 would power it very scale like.

Dennis