25cc gas engine
 

a 25cc gas engine is equivalent to what size glow engine?

The NGH 26 is rated at 2.7 hp
The oS 90 is rated at 2.9 hp

It depends on the particular engine.
Gas engines are similar to 4 strokes in the fact that you can use larger props, engine manufacturers power figures mean nothing really.
A good approximation is 20%-25% lower power than the same capacity glow engine.

25 cc is 1.586 cu inches or 1.6 inches.About the power of a 1.2 glow engine.
BCCHI

Within the gas engine ranks, there's a HUGE difference between the latest generation of engines, and the not so old, but still early generation of engines.

Point being, it's virtually impossible to have a table showing direct gas vs. glow comps using displacement only as your guide. You can't even do that gas vs. gas.

A US Engines/Quadra 41 for instance, uses a magneto for spark, and weighs about 5 1/2 lbs.(if my memory is right?). A 30cc DLE can easily do about anything the Quadra can do, while being about half the weight of the Quadra. Some have compared the output of both these engines, to something in the 1.60 -1.80 range of glow engines.

Second point being, you really have to compare weights, as well as prop turning ability when comparing engines - no matter fuel type.

To answer the question you asked in the other post, without more specifics, my guess is you'll be overloading, but possibly not over powering the Stick.