Cartridge Start spool up slow?

[ShuRugal]

Starting the engines with the pyrotechnic charges seems slow?  the spool up rate using the cartridges seems to be about the same as using the air source starter.

Considering that the pyro charge only burns for a few seconds, this seems slow?  Every real-life pyro start i've seen kicked the engine core up to self-sustaining RPM in just a few seconds.

 

This video of a Canberra doing a dual cartridge start appears to take just 4 seconds from firing the cartridge to the engine being at ground idle.

 

 

in this video of an F4 cartridge starting, the charge fires at 12 seconds, and by 18 seconds we can hear that the engine is accelerating under its own power, which means it must be at least 35-45% RPM (45% being where the book says the engine is self-sustaining and the air hose can be switched to the other engine).  After that point, it takes the normal time from "sustaining" to "idle", but "zero" to "sustaining" is much more rapid than currently in sim.

 

When you think about how a pyro start works, this is the expected behavior.  The cartridge cannot sustain the volumetric rate required to turn the air impeller starter for more than a few seconds, so the tradeoff is that it makes the gas flow that it can at absurdly high pressure in order to accelerate the engine to a self-sustaining speed in as few revolutions as possible, so that it gets there before the cartridge stops burning.

 

I'm sure this will be addressed as the module is tuned, it just stood out at me when i was playing with the feature, so i figured i'd comment on it.

Edited May 29, 2024 by ShuRugal

[Dominik96]

Good point. I made it faster.