2C vs. 4C in 3D aerobatic planes
I have used an OS FS-52S and an Irvine 53 on the same plane.
The two-stroke 53 puts out a lot more power than the four-stroke 52. I know that 53 is quite a bit larger than 46, but I would still think that a 46 two-stroke would be more powerful than the 52 four-stroke.
Even though the Irvine is ported for torque, most of the power is found at high rpms. The FS-52S responds quicker, and its strength is low rpm torque. So I would say that a four-stroke generally is better for 3D than two stroke. One reason is that they have a wider power band, another reason is that the throttle response is quicker. But this is only my personal opinion and not a generally accepted truth. The OS FS-52S is the only four-stroke engine I have flown, so there might be a lot of things that I don't know.
If you go up to a .70 size four-stroke you will have an engine that has lots of power. The drawback is that you get more weight along with the extra power compared with the 52. If the plane can handle a two-stroke 46, I think it will handle a four-stroke 70 as well. (IMO)
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