Pretty much what everyone else has been saying: 20FP or 25LA for the Streak, and 46LA for the Nobler. If you have a 40LA lying around then by all means use it (in the Nobler).
Note that Enya engines are also well regarded, as are various four strokes. I have a Magnum 36 which flew very well in a Twister until I crashed it through sheer stupidity -- it's now flying very well in a Twister-sized trainer. I think that would pull your ARF Nobler around very well.
The Nobler that my flying buddy built came with its own weird triangular tank -- it looked like it was purpose-built for the plane, and it was more than four ounces. My recently retired Sister Jenny was a restyled Twister that weighed 53 ounces; it would almost fly the pattern on four ounces of Power Master 10% fuel -- and when I doped up the fuel with two ounces of Colman lantern fuel per gallon, it did fly the pattern on a 4 ounce Hayes tank. So it can be done with a four ounce tank, although a 5- or 6-ounce tank is probably wiser.
Topic: What engine would you use in ARF Flite Streak an Nobler (Read 3705 times)