Jetcat P80 Start problem

[ian200]

Hi all,
I hope you can help with a problem I’m having with my Jetcat P80. After a couple of months not running my turbine I decided to give it a test run and found that it wouldn’t start. The I/O board lights blinked in the correct sequence once the start sequence was initialised but I didn’t have the audible tones from the turbine + the starter would not initialised or run. The ECU didn’t recognise that the starter hadn’t operated and carried on with the start sequence pumping fuel into the Kero start injector. I have checked all of the connections and re learnt the transmitter and ECU. I can’t understand why I’m not getting the audible tones from the turbine that mirror the I/O board LED’s
Any ideas would be greatly appreciated.
Thanks
Ian

[Richard OConnell]

Sounds like either a bad cable, sensor, or your I/O interface. Do you have a second controller to test the engine with?

Finding out if individual parts inside the engine itself are easy to test, after that the blame has to fall on the computer itself.

[ian200]

Hi Richard,
Thanks for you reply. I’ve found the problem. The audible tones are generated by the starter motor so I looked at that in more detail and found that it was open circuit. Once I dismantled it I found that it was completely burnt out. I’ve now ordered another one. Now it’s a case of figuring out why it burnt out? If I find anything I'll post it here.

Kindest regards
Ian

[Richard OConnell]

Hello Ian.
You have perked my curiousity when you say "burnt out." Was it the actual motor itself or an electrical component? If the starter motor shows signs of physical damage or bloating it could very well have been cause by the starter being engaged while the engine itself was operating under high RPMs. I'm not sure on the starter layout on those motors, but on a lot of APUs, there is a clutch system in place to prevent the engine's high RPM output from tearing the starters apart.

[ian200]

Hi Richard,
Yes it’s very burnt, it’s all black inside and the little motor brushes have melted into the plastic housing.. I think your right it could have only been caused by the bendix being stuck to the compressor cone. During high rpm it would have turned the motor into a mini generator that burnt it out. The thing is I would have noticed the lack of the cool down phase once I shut the turbine down so it’s still not conclusive. I have now replaced the motor and all is working well.

Kindest regards
Ian

[Richard OConnell]

Hope the new motor solves all your problems