ORIGINAL: MTK
Retuned the engine for premium autogas. Surprised to find a considerable bump in power output over Avgas. The engine is pretty well broken in so the numbers I am getting now should be a bit better than a couple months back, but still this much was unexpected....
18x10 3 blade Mezjlik, 8150-8200 rpm at full revs, 7400 at mid throttle where I fly (Avgas ran about 7700)
20x10 MDK Hybrid, 7920-7950 rpm at full revs, 7150 at mid throttle where I fly (Avgas ran about 7400)
These are steady state numbers. The TNC tach also has a peak rpm feature; these were not peak numbers
Just received 19x12, 19x13, 20x12 and 20x13 Xoar electric wood blanks to be laminated into MDK Hybrids. I'll have numbers in due course.
The bump in power should not be surprising. AVGAS is slower burning due to the amount of TEL. IF that was removed the flame front would burn faster, probably too fast for a slow reving 2 stroke to see the benefit but it would help it maximise its potential on the curren tune. Pipes, more aggressive jetting and porting would yield even more power.
There are some 4 stroke racing engines that useethanol to an advantage they can change the transition from lean to rish and back again at different loads to optimise the power band i.e. broaden it to improve acceleration and top end.
With some development of our little petrol engines I'm pretty sure we will see significant improvements in the exploitation of E10 through clever timing curves, more agressive porting and dedicated pipes
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