Is it possibly to estimate what ignition timing a glow plug engine have. I suppose it is before TDC, but how much?

You can just measure it with a degree wheel, they're all different. Here's a post that talks about it:
http://www.flightlines.com/forum/For...ML/000364.html

I don't see how that can be measured. The Fuel ignites by the glow plug. but it is glowing all the time (like an old oil engine).

Hej!
Varför vill du veta det??? Kan inte förstå vad den kunskapen skulle användas till....Berätta

Hälsningar!
Jan K
Väsby MF

Jag är en "motor man" och bara nyfiken på vilka premisser en 2-takts motor av det här slaget fungerar. En liten glödstiftare är rätt så lik en råoljemoter. Bara mindre och annat bränsle och framför allt, tändningen går inte att styra.

It's almost (but not quite) impossible to say when ignition occurs in a glow plug engine because of all the variables. However, I have a graph made up by Brett Buck from cylinder pressure readings gathered by Sott Bair in tests done on a Super Tigre 46 running in a 4 stroke at 7500rpm. The graph is actually instantaneous torque at all degrees of crank rotation but it can be interpreted as showing where ignition occurs. The graph shows a sudden rise in torque (pressure) at approximately 25 degrees BTDC.

Interesting. That appears to be realistic. It must say something about the engine or combustion chamber efficiency. Now I only have to check with other two-stroke engines.
Why, you may ask?
It can't be wrong to be curious.

But it can be lethal.

The warning is apprehended
(did I express this right?)

Close, but not quite. Our police apprehend bad guy's. We heed warnings.

Damned! But apprehend has two meanings?

apprehension 1. what police do 2. light fear (sort of)?

My nose apprehend the prop.

That would be apprehensive. Such as " He was apprehensive about flying his new large scale airplane".