Technam would be smart to upgrade the P2006T with the new Turbo Rotax 915 135hp engines.
I refuel with E 5 (<5% ethanol), you’ll rarely find 5% in it, rather something like 1-2%. You simply don’t have to bother all the time. But true – the fuel-system has to be ethanol-resistent as well.
europaxs wrote:
whereas the Rotax runs happily (and is approved) for 10% Ethanol.
How much ethanol can a fuel system in a given airframe take is also a question. AIUI “aviation grade” mogas shouldn’t contain any ethanol.
europaxs wrote:
The biggest advantage of the Rotax is it’s ability to run without leaded fuels, not in fuel savings, I think.
boscomantico wrote:
…which all Lyco / Conti engines in the same power range can do just the same…
The Lycos do not tolerate ethanol
http://www.lycoming.com/portals/0/ourinnovation_fuels_unleadedfuels_part_2.pdf ,
whereas the Rotax runs happily (and is approved) for 10% Ethanol.
That is a major difference. When I wrote unleaded fuel I didn’t mean exactly UL91, rather ALL unleaded fuel with at least 95 RON and <10% Ethanol.
Peter wrote:
Also 91UL is not significantly cheaper than 100LL, in the UK at least.
In Sweden it is 10% cheaper.
Also 91UL is not significantly cheaper than 100LL, in the UK at least.
Avoiding the lead deposits is good though.
…which all Lyco / Conti engines in the same power range can do just the same…
The biggest advantage of the Rotax is it’s ability to run without leaded fuels, not in fuel savings, I think.
Yes indeed. I reckon that, the smaller the craft, the more important the power/weight ratio. Go heavier and you can better afford to aim at better efficiency, and invest a bit of weight there. “Economy of scale” is the name of that game, ISTR? It is why they make ships so big.
This “Rotax v. Lyco” thingy has come up many times e.g. here.
I don’t think anybody has shown a Rotax delivering better SFC in cruise. It’s hard to see where it would come from. Obviously they are more efficient in climb (where a Lyco has to run very rich because of the need to keep CHTs down) so overall you have a saving in typical operations. The biggest savings come from the planes themselves being much smaller.
Power to weight ratio is a different thing and is “easy” to achieve – just rev it higher, and better still turbocharge it 
But you lose efficiency at higher revs.
