Rob L wrote:Flyin'Dutch' wrote:Ugh, maybe for a lawn mower not too bad but I would not want to inhale AvGas fumes from a chainsaw etc.
The LL is a total misnomer - there is (IIRCC) 10x more TTL in AvGas than there was in 5 Star Leaded for road use.
It's TEL But you are quite right; Low Lead is a relative term.
Think of the 130 octane used for all those bombers & fighters in WWII.
I confess that I always thought 100LL was about the same as five-star in terms of lead content.
Chainsaws are generally 2-stroke, so the above does not apply.
andytk58 wrote:I still think its criminal that aircraft are designed with fuel systems that suck liquid. Particularly a volatile liquid which will flash vapourise at any excuse!!
IMO mogas systems should always have an 'always on' circulating pump at the lowest point in the system, with a pump failed warning lamp on the instrument panel. Cheap insurance against disaster.
riverrock wrote:My understanding is that most injected engines essentially have a circulating pump, pushing fuel around much faster than the engine needs (our Bulldog goes anyway), but can still get vapour lock, although its post common when trying to restart a recently running hot engine.
andytk58 wrote:riverrock wrote:My understanding is that most injected engines essentially have a circulating pump, pushing fuel around much faster than the engine needs (our Bulldog goes anyway), but can still get vapour lock, although its post common when trying to restart a recently running hot engine.
The issue isn't so much a recirulating pump, but the location of the pump. Engine driven pumps are dangerous as once heatsoaked, any attemot to suck the fuel up from the tanks results in vapour lock.
The pump really has to be at the lowest point on the system so it had net positive suction head under all eventualities.
Crash one wrote:
I’m led to believe that these engines were initially designed to drive farm tractors which had the fuel tank well above the engine. Not much can be done about it now but the mechanical pump being at the top of the engine and in a low wing aircraft, it’s in about the worst place possible.
Crash one wrote:I hope that was tongue in cheek.
However. I believe that in the 1930s or thereabouts the Continental engine was designed for farm tractors,
Being very successful and reliable it was adapted for use in aircraft.
Then, aviation being the way it is, very little modifications were performed and they started being built for and fitted to aircraft.
My engine in my Emeraude was never ”once in a tractor”! It was built in 1959 and fitted in the aircraft brand new as were numerous others.
andytk58 wrote:I wouldn't be at all surprised to learn that Continental started with farm machinery.