It does…
this has lead to a question whether to use massive or fine wire. Comments please about advantages/disadvantages and also any brand preferences. The engine is an IO360KBIB.
I think this deserves a new thread!
Quite right. I gave no consideration to mixture. What I meant was that if you have 1200 RPM and 28" MP, you may harm your engine unless the POH says it is OK to do so.
Thanks for all the information so far. I have researched on these forums the problem with Champion plugs and this has lead to a question whether to use massive or fine wire. Comments please about advantages/disadvantages and also any brand preferences. The engine is an IO360KBIB.
Of course it is. But if you do not know better (read: have not read the manual) you will probably not hurt anything by abiding it.
You can by exceeding CHT. For TB20 WOT in combination with full-rich ensures enough FF to keep CHT within limits. Closing throttle (lowering MP) in this situation is not recommended.
The “don’t operate over square” thing is an old wives’ tale.
Of course it is. But if you do not know better (read: have not read the manual) you will probably not hurt anything by abiding it.
Radial engines are often supercharged to relatively high MP and have large cylinders, which are both potential causes for detonation problems if operated improperly. A 150 HP Lycoming is for sure a different situation and the operating manual allows sea level full throttle MP at anything above some modest rpm like 2300 (I forget the exact rpm). A 180 HP Lycoming or the six cylinder version of same needs a little more rpm for full sea level MP due to slightly larger cylinders, but it’s still not greatly constraining per the manual.
I’ll remember the 1 inch per thousand feet rule of thumb, I’d not come across that before. I have a few power settings memorized, with higher rpm for the same power with increasing altitude, but mostly I don’t shoot for exactly 65% or whatever – the engine doesn’t care about such things.
I think it comes from the days of large radial engines. I hear that it could do some damage to them.
The “don’t operate over square” thing is an old wives’ tale.
Of course it is nonsense. There is no physical connection between MP (expressed in inches) and RPM. They are different units. It’s like saying a car should not be driven at a speed which when expressed in MPH is greater than the length of the car in inches.
This stuff comes, I believe, from the FTO (ATPL) training environment. I don’t think it comes from the PPL system because they rarely operate variable pitch propellers.
The “don’t operate over square” thing is an old wives’ tale.
http://www.avweb.com/news/airman/184483-1.html?redirected=1
