Hello Guys

Just got my shipment from tom which includes my first ever DA engine.While reading the manuel i see that using AV GAS will void my warranty.That's no fun, i have lots of AV GAS which i use in my brison 2,4.I love it,no smell and is much better that the pump gas we get here in the caribbean.
I also saw in a book form Don's hobby shop that he has been using AV GAS for years with out any problem.
Any of you guys use AV GAS with your DA's,if so have u had any problem with it???
What's so different that brison says yes knock yourself out and DA says it will void your warranty


verne

what is AV gas????

aviation gas (AVGAS)

A guy in our club uses it in his DA100 and says he loves it; big difference in throttle response and idle, but I have no problem with pump gas, to each his own.

AV gas is higher octane, which will have an equivalent effect to retarding the spark timing. This can cause overheating in extreme cases.

I would guess (but this is not factory authorized advice) that advancing the timing a couple degrees ought to get it back to where it belongs and should run great. But check with DA is good advice.

TF

Another reason not to use "Avgas" is because it is also a "low lead" fuel. I've used a tremendous amount of 100 octane avgas in 100cc engines and had to toss most of them after about 60 hours of running time due to extremely high lead and carbon build up. The lead fouls plugs quite quickly, BTW, even the avition type used in some Herbrandson engines.

Pat

Thanks Guys.

I will give DA and call and do what's best.Silversurfer when you say (toss them) do you mean they could not be fixed and u dumped them[&o].
I only fly on sunday and only about 5 flights per plane but so for the brison is doing fine.in the last year i have cleaned the plug about 3 times.

verne

There is no reason to run AVGAS in yout DA50. Low lead in the aviation world means tons of lead in the automobile world. Lead in used to get the octane way up there around 105-110 in automotive terms. Lead is also good for valve seats. AVGAS also has a lower specific gravity which is like saying it's less dense. That means it runs leaner per volume. High octane causes a slower flame front or a slower burn of the combustion mixture. In a two-stroke engine where the intake and exhuast happen on one up stroke and then one down stroke slow combustion is not what you want.

What happens in the real world is that people try AVGAS and due to the lower specific gravity it runs leaner and people think that because it's crisper in response and pulls a few more RPM it must be better. What's really happening is that there engine is running leaner. You would be better served twiddling your needle valves yourself on 91-92 octane automotive fuel. No lead worries, faster flame front, less cost and no carbon build-up problems. OK, AVGAS does smell sweet when burning, I'll give it that!

AV gas has more lead than the gasoline that we used to get. That mixed with oil, you get fouled plugs, carbon buildup and pre-ignition after a while. I did see that you are in the carribean and I know that gas is extremely high there. So I don't really know what to advise other than like others said, call DA. Sorry I am no help.

yes I pay about $4.60us for pump gas and about 4.80 for AVGAS.At brison they said i would be better use AVGAS,because the quality of our gas is so bad and the octane is so low.No one on the Island can even tell me what the octane number is.
I will call DA and hesr what they say.

Thanks everyone

That's correct. After 50 to 70 hours we removed them from the airframes and tossed them in the dumpster. The cost of returning them, having them rebuilt, and re-shipped back to us exceeded the cost of a new engine. Since we went through a lot of engines, it was more cost effective to junk them. The work involved in re-working them, plus the paperwork involved in shipping a used engine from a foreing locale, made hanging on to one for yourself not worth the effort.