Brian's pre rotator

Echo 2 · 30-05-2007, 07:48 PM

Brian,
thought I'd start a new thread about your spinnerupper - have you found what's causing the problem?
I used a Toyota Camry starter & so far is working good , the only thing I noticed is the engine revs picking up slightly when it's engaged

. I havent fitted a soft start yet , but giving the blades a good spin by hand before climbing in is all I've done in the past.

By the way , my new 29' AK's are very smooth & spin up quick , just like my last two sets

Echo

mceagle · 01-06-2007, 10:33 AM

Eric, are you using the standard Subaru computer?

Echo 2 · 01-06-2007, 01:59 PM

Tim,
yes , a three pin , ( if that means anything ) it had a four pin but we decided to change it .

Echo

mceagle · 01-06-2007, 04:45 PM

No worries - just trying to find out why your engine revs picked up and now I know.
Thanks Eric.

Echo 2 · 01-06-2007, 09:06 PM

Tim,
I don't suppose you could pass on 'why' ? Is there something wrong with the standard computer ?

Echo

mceagle · 02-06-2007, 04:42 PM

No problem at all Eric. The computer detects when there is any access load on the engine (like headlights turned on or the air con turned on) and it compensates through the idle stepper motor on the throttle body and brings the idle up a bit..

Echo 2 · 07-06-2007, 07:23 PM

Thanks Tim,
everything seems to be working fine , the maiden flight went without any problems ( apart from the hose on the ASI coming off & having no display airspeed ....

)

Echo

Brian · 09-06-2007, 06:12 PM

Hi Eric, god idea to start a pre rotator thread.
Just got back from up north.

Well, Rosco put a new starter motor on, new electrical leads/ battery. cleaned up earths etc. Did not make any difference so I decided to try another tack, I now warm the engine up, turn off the engine and pre rotate then start the engine and all works well so the problem is still there, could well be a crook earth somewhere .

Good to hear the maiden flight went well !!!

Adrian S · 11-06-2007, 06:19 PM

Brian,

I have seen a similar problem in the past in a gyro with a EA81- Injected and Turbo'd with a Wolf 3D computer. After lots of searching it turned out that there was a voltage drop below 6 volts when the pre rotator was engaged and this was caused by a faulty master solanoid in the electrical system that was starting to break down.

This was only occuring when the current through the master solanoid exceeded 180amps ie engagement of the prerotator.

Hope this helps.

Adrian.

Brian · 11-06-2007, 06:42 PM

Thanks Adrian, its a funny one as originally, I did not have this problem, hit the button and the rotors would get to about 80 revs before the engine would start to complain. It seems the method of switching the engine off works successfully.
Could circumnavigate the problem by having a second small battery driving the computer but this just adds more complexity to the whole thing.

I'm enjoying hearing and seeing those rotors getting up around the 100 revs in one go !

Nothing worse than not being able to get those fiberglass blades humming along when the wind is blowing a gale !