Fri Feb 26, 2021 8:38 am
#1829146
Was there any noticeable performance difference johnm ?
MarkOlding wrote:Was there any noticeable performance difference johnm ?
2 Introduction
2.1 Because of the difficulties experienced in obtaining Aviation Gasoline (Avgas), particularly
in small quantities, and the ready availability of Motor Gasoline (Mogas), CAA was
asked to consider permitting the use of Mogas in general aviation aircraft. This was
granted under the auspices of Generic Concessions (GCs) 2, 3, 4 and 5, published in
CAP 747 (previously Airworthiness Notices 98, 98A, 98B and 98C), which allow
microlights and certain light aircraft to use Mogas, subject to the conditions therein.
2.2 Since the publication of these documents, the composition and properties of some
Mogas fuels has changed and it is becoming increasingly difficult to obtain Mogas that
does not contain any alcohol. With the exception of microlights, the use of Mogas
containing alcohol is generally prohibited in aircraft.
2.3 This Generic Concession, by means of the attached Exemption against Article 33 of the
Air Navigation Order 2016 (as amended), permits the use of a new unleaded aviation
fuel, UL 91 Avgas, in Annex I aircraft, subject to the conditions stated in this Concession.
MikeB wrote:
As for E10 Mogas (which will be here from September) - the UK is sticking with 5% max ethanol for Super Unleaded for the time being, so that will remain an option for the Mogas fleet.
In Europe, the octane rating on the pump is simply the RON figure. America, by contrast, uses the average of the RON and the MON figures, called the AKI (anti-knock index). Thus, 97 octane “super unleaded” in Britain is roughly equivalent to 91 octane premium in the United States.
OpenCirrus619 wrote:
In my case I can't use UL91 - the manual explicitly states a minimum octane rating of 95.
OC619
skydriller wrote:Out of interest, does anyone know if its possible to remove ethanol from Mogas?
ThePipster wrote:OpenCirrus619 wrote:
In my case I can't use UL91 - the manual explicitly states a minimum octane rating of 95.
OC619
95 RON or MON?
UL91 is 91 MON which equates to 95 RON
Pipster
MichaelP wrote:From memory the Rotax 912S has a 10.5:1 compression ratio which is higher than many Lycoming ‘high compression’ engines.
The 160bhp O 320 has to run on Avgas, but its compression ratio is 8.5:1 so there’s something odd about this argument.
cockney steve wrote:Having read on this Forum, about the availability of "Super" without Ethanol, I did a web-search and found the only Esso station within 10 miles. A month later, it no longer has Ethanol-free fuel of any grade. I expect this is as a result of reduced demand and refineries closing.
!