Frank,
Comparisons of oil performance and fuel mix are hard, because nearly all of it is anecdotal. And since few people will believe someone else's experiences, or setup, or...whatever, they just start from scratch again. Go back and read 10 years of Stunt Hanger, or even further back in the Stuka Stunt archives. The sun comes up in the morning just like it was the first time, and people want to run chain saw oil that is not meant to mix with alcohol. Or 5% nitro in a Cox. Let's all debate that for a while. They want to run all-synthetic, because it is so much easier to clean off the plane afterwards when compared to castor. Even in a engine with a sintered piston and mild steel sleeve. And so on.
To do the testing is both tedious and expensive. You have to do the testing very carefully, or what it proves is not what you set out to prove. For example, if I took two new Fox engines, and broke one in on 10N-22Syn-69Al, and one on 5N-29C-66Al, what did I prove? Before I even start, I am not sure the fits in the engines are equal, or the lower end of the rod, or the main bearing. This is true even if the Foxes were essentially the same vintage, say 40th Anniversary models. (Which seemed to run better for me than earlier versions.) And if we are going to run a synthetic, which synthetic? They are not the same. So results in a small sample test program have to be controlled very carefully, or it really is just another piece of anecdotal data. If you had two Enyas from the same lot, that were both brand new, you'd have a starting point. But with just two, what single variable are you going to pick for your study?
The first place you should look is at the fuel testing that John Kilsdonk did, probably in the early 70's, if I remember correctly. I think I read an article in Model Aviation back issues someone gifted me. I'd believe those results. He was an engineer and definitely knew what he was doing. Or if there was any testing done by Maynard Hill for his endurance record attempts and his cross-the-Atlantic flight. He was a scientist and a pioneer. I'd believe those results too. There was earlier stuff that was done during preparations to fly an R/C plane from Long Beach California to Catalina Island probably back in the early 1960's. John Brodbeck (K&B) might have been involved in that testing. He built engines for a living and may have repaired more engines that were mistreated than anyone, ever. (He used to run a free engine repair shop at the NATS.)
As for me, I flew F2C team race for 3 or 4 years. So I mixed lots of diesel fuel. But those are BB engines run right to their limit--with one great advantage over stunt planes. When the setting goes over, you pop the shutoff, pit and reset the compression. And with AAC metalurgy, it's a whole different thing than talking about most of the engines on your list. And on things like PAWs or Cox conversions, you need a lot more oil to keep the bottom end from excessive wear.
Perhaps it is also relevant to mention that I participated in hardware life testing for an aerospace company.
Divot McSlow
Topic: UNCLE, I give up! Fuel mixes Too many!!!!!!!!!!!!!!!!!!! (Read 1240 times)