- Jun 18, 2020
- Reaction score
Thanks Peter, I think that's good advice. And seems to corroborate with the data/chart assuming its correct. What I hadn't appreciated is how 7075 necks down like that at elevated temperature, so learned a few things. Now, is it truly operating in that high temp band, who knows. Some commercial glow engines are pretty thin & swiss cheesed by comparison, although they likely have their own alloy recipe & are forged. Maybe better than bar stock, but doubtfully Kryptonite
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I too ran Nelson engines mostly high performance ducted fan engines I flew these on pattern planes running on heavy nitro as I had ready access to it. Being a racer at the time more of anything was better. S couple came apart pretty spectacular separating the head piston rod from the crankcase the ducted fan engines were capable of some serious rpm and power When they came start not much was left . None usable . My big twin was really fast we didn’t have timing devices then the cops radar would not lock on beyond about 125 mph even with foil taped on .Thanks Jason. yes I have that Jim post bookmarked. Fantastic wealth of information. And probably where I heard the (RSA-444 T6) piston alloy mentioned. I'm quite familiar with Nelson engines (or at least used to be in a former hobby life). But running them is different than building them haha.
Early car race pistons were of som eeldsblr aluminum we burned pistons regularly i machined out the burned area then welded it up I had a neat fixture to hold pistons in the lathe or mill later pistons were probably 7075 as they were no t weld able most are coated or hard anodized now so not weld able I just cut new grooves for double or thicker rings. Lawn engines and two stroke engines don’t have ver eeldsblr pistons now either.. I used to be concerned about this but now for race cars it more about the $300. Each for new pistons.