Posted Thursday, August 23, 2007 @ 02:30 AM  

Quote:

Originally posted by Jorgen sorry all you guys with electrical starters- you just shouldn´t ruin the beautiful lines of the nose with that ugly bulb

Amen!!!

Posted Wednesday, September 5, 2007 @ 04:53 PM  

Here´s an update on my starterwire repair, it turns out Bob was absolutely correct, I just wound the spring two extra turns and the tension is back up. Unfortunately the wire has probably been harmed by the slack with some tangling and fraying, eventually I will have to change the wire, I think.

It´s an easy access repair. Undo the nut on the cap (9 mm on XST), the wire goes 1,5 turns around the ca 10 cm diameter starter cogwheel which gives you about 45 cm of pull which is the range of the starterhandle and your arm in the cockpit for that matter (pic 1 “starterwire1”). The far end of the wire has a ca 5 mm sphere clamped on the end which sits in a groove/hole in the starter cogwheel. Turn the cog wheel anti clockwise and you can easily undo the wire and take the sphere sidewise out of it´s hole. When re-mounting it you can choose how much tension you want, simply turn the cog wheel until you get enough tension. The cockpit end of the wire looks as it has a clamped on tellurite (pic 2 “starterhandle”). I don´t know if you can get this type of wire at an ordinary shop, I´ll have to check.

The tension of the rewind spring is a balance; more tension gives less risk of tangling of the wire BUT makes it heavier to pull the starter handle. Even so, it´s probably better to have the spring too hard than too loose, it might be heavier to pull but tangling of the wire blocks function altogether. Try it out yourself, wind the spring and make a couple of test pulls.

I also had some wear of the cap on the starter cog wheel (pic 3 “startcap”) which is fixed via a rectangular hole to the non rotating axis of the starter cog wheel. If I would have been a trifle less lazy and checked the mechanism more often the damages had probably been avoidable…

Posted Friday, May 9, 2008 @ 02:35 AM  

Thanks for posting all your comments. My hand starter seems to work fine in regards to the recoiling issue, but here is the question:

How does the mechanism get pulled away from the spinner back plate after hand-starting the engine? My starter cog stays uncomfortably close to the back plate after turning the engine (which hasn’t run yet…)

Also, there seems to be a lot of free play in the main pivot of the mechanism (red circle, I am using Jorgen’s photo again). Is this normal or do I have excessive wear in it?

Greetings from downunder

Tim

Edit: So....how do I attach an image?

Posted Sunday, May 11, 2008 @ 08:35 PM  

[Edit by flyingkroeger on Sunday, May 11, 2008 @ 08:38 PM]

Posted Tuesday, May 13, 2008 @ 06:38 PM  

Anyway, the starter mechanism as I understand it rotates (clockwise) back from the spinner back plate because of a push from the tube around the wire when the recoil spring pulls at the starter handle and the wire is wound back onto the cog wheel. The tangling and fraying of the wire I´ve seen comes from the wire beeing too loose when recoiling, and it has hopped over on the front side of the peg (inside the red circle) on a number of occasions. If you´re not happy with the pullback force, I suggest you start by checking the tension of the spring as described above.

How much play is OK? In Swedish we have a special word similar to "enough" but even more so, if that makes any sense. On XST, the mechanism is a bit "ricketty" too, but the wire tracks well now that the tension is back up so I assume it´s OK. If in doubt, why not dissamsemble it and check for excessive wear? Take some pictures and share it if you do. I´m allways interested how mechanical things look on the inside....

Posted Friday, October 24, 2008 @ 09:56 PM  

As usual, I’ve copied-n-pasted all this text into a useful document to go into my maintenance files.
This thread is particularly interesting for me because our British RF4 has a starter problem, in that the little cog is reluctant to swing back from the propeller back-plate after use. This has clearly been the case for some time, because the teeth have been badly worn away on one side of the small cog. I didn’t dismantle it, because I had so much other work to do on the aeroplane, but confined my investigations to adjusting the tension on the return spring from the cap of the small cog to the cylinder head stud.

What return spring? You may well ask. I had not realised that the spring fitted to WGN is not standard. I only discovered that when I got back to ‘Aussie Blue’ HDO and saw a) it does not have one and b) the starter worked fine with no tendency to stay in the forward position.

WGN’s (non-standard) return spring is very tricky, and has to be adjusted very precisely for the starter cog to swing forward when the starter handle was pulled, but for it to swing back again afterwards. If the spring tension was too strong, the small cog merely spun without moving into engagement with the prop back plate. With too little tension, the teeth would engage, but the small cog would not swing back out of engagement again. I now suspect that there is some incorrect excess friction somewhere in the system, or it is incorrectly assembled – no surprise when you know about all the other things that were wrong with that aeroplane…

As an aside, I have to admit that one reason for my poorly executed stall turns at 300 feet over the Thames in front of a big crowd was my worry that if I stopped the propeller (as my stall turns so often do) that awkward starter MIGHT NOT WORK when I wanted it and I would end up in the river!

Posted Thursday, April 2, 2009 @ 04:53 AM  

I think Ken Ballington's got them.

I've ordered three.

Watch this space.