[scarier]

Duuuuuude, TIT is the temperature after combustion, not compression. Adiabatic compression isn't even close to the main contributor to TIT--heat input from burning fuel is. Also you may be confusing turbofans and turboshafts--helicopters have torque limits (not a helo guy, but my understanding is this is a gearbox or masthead structural limit rather than an engine limit), but if your turbofan can't hit RPM limits on the ground on a cool day you should seriously consider bringing it back for maintenance instead of going flying.

[jmward01]

There are a lot of variations. I am most familiar with turbo props so shaft hp is the limiter on the ground and TIT is the limiter at altitude. TIT, of course, gets most of the heat from burning and I did mess up my explanation a bit. Sorry about that! You may be surprised how much of that TIT comes from compression though. The main point still stands, check the temp of that compressed air at sea level vs at altitude and for the same PSI out of the compressor you get a lot more heat at altitude. Either way though, the original point remains, electric has no TIT limit and you don't have to deal with 1000c materials spinning at 100k RPM so way simpler and easier to build something that keeps delivering thrust at extreme altitudes.