Thank you for this insight Chris. I understand the concern regarding the Tomboy being tail heavy. I watched the Mark Robinson videos and he used carbon fibre control rods on his version to keep the tail weight down. Please can you shed some light on the engine choice? I could try to find an Irvine Mills 1.3 and use a big prop like the 10 x 3-1/2 or a 9 x 4. or for a bit less buy a new PAW double ball race R/C and have throttle control. The Mills would keep it vintage which is what i wanted to do, but if it is not able to power it then a more powerful engine is needed. That was why I was considering the Aurora Indian Mills 1.5. I tend to agree with you that a 15% increase of "not a lot" will be pointless, especially if a decent Irvine 1.3 might be as good.