The tips of the combustion wheel heat up pretty quickly, this is the danger time as slow starts keep the tips to hot for to long which can damage the blades.
Hi John This APU's are designed for starting the primary engines of Aircraft. It creates massive air pressure which is piped into the primary to spin it up. So run duration is generally around 10 to 15 minuets. Longer would strain the engine or overwhelm the cooling system. I only run them up for short periods just for the sound. my maximum run time has been about 5 minuets.
Like that whine
It's very beautiful engine
Its a Old Russian design and really simple to work on, but looks more than it is !!
Why can't it stay running
Hi John
This APU's are designed for starting the primary engines of Aircraft. It creates massive air pressure which is piped into the primary to spin it up. So run duration is generally around 10 to 15 minuets. Longer would strain the engine or overwhelm the cooling system. I only run them up for short periods just for the sound. my maximum run time has been about 5 minuets.