Starter "fun"

Nice sunny day this morning so I plugged in my preheater and headed to the shop. Squalls were on their way when I poked my head out the door about 4 hours later and wasn't going to miss the opportunity for a quick flight so pulled the plane out, jumped in and fired her up.

Started right away, but I had that mental feeling something wasn't right. Amp gauge jumped over to 30A and I brushed it off as the first run in quite awhile and cold. Volt gauge always needs a light tap to get it off the seat and then it's fine, but this time it only got to 10volts. Again shrudged it off as a cold instrument sticking. There I sat for almost 10 minutes letting everything warm up before heading into the snow. Now I thought I smelled something odd and wait...what's that weird noise. About 11 minutes into this the sound became a clanking like the prop/spinner was falling off. I turned off the mag switch & master to shut down quickly. Got out moved the prop and found the starter not engaged but just rubbing the flywheel ring. After I was done calling the Skytec corp every name in the book (82 hrs on this one! and as I stated before on this forum I love them). I got back in again and turned the master back on. Didn't dawn on me right away what was happening but the starter was running when I threw the master switch!! I turned it on and off a couple times and this quit happening, then got out with a big screwdriver and pushed the bendix back from the flywheel, turned the mags on --hand swung and got in my flight before "winter" returned. Full 13.8V+ as soon as it started up so everything now fine in this respect.

After the flight I came to the conclusion that the remote starter solenoid must have stuck in the energized positon. Once the engine started and I moved the key to Both, the solenoid must have stuck from frost/cold/spark weld or something and held the starter engaged and running on the flywheel, causing the 10 volt reading high charge current etc and of course the expensive part a totally mangled bendix drive on my Skytec 122PM . I have removed the remote starter relay from my firewall and am replacing with a new one while the local electric motor rebuilder has a go at my starter drive(Experimental - I can do this).

Other than sharing my shitty day and the advise that when it just doesn't look/feel/smell right it probably isn't....has anyone else ever had this happen to you and is there any experience with or chance that my OFF/R/L/BOTH/START key switch was the culprit and the internals of the switch stayed connected to the start circuit even though I had turned it to both and actually all the way back to OFF and the starter would run when the master was turned on. Would hate to get my starter back on with a new remote starter relay and have this happen again if someone else on here has ever had the mag switch start postion stick I'd sure like to know. And yes I know many of you have seperate toggles/switches and a start button, but there are at least a few "reworked" panels and experimentals hanging around here.

Thanks,
Wayne

irishfield said:

has anyone else ever had this happen to you and is there any experience with or chance that my OFF/R/L/BOTH/START key switch was the culprit and the internals of the switch stayed connected to the start circuit even though I had turned it to both and actually all the way back to OFF and the starter would run when the master was turned on. Would hate to get my starter back on with a new remote starter relay and have this happen again if someone else on here has ever had the mag switch start postion stick I'd sure like to know. And yes I know many of you have seperate toggles/switches and a start button, but there are at least a few "reworked" panels and experimentals hanging around here.

Thanks,
Wayne

Click to expand...

Wayne...

Had it happen to me in a Bonanza once... Did the tractor fix and hit the solenoid with a screwdriver handle and started it again... Simple to wire an indicator light in the starter wire... Like you hadn't figured that out already!...

When Pigs Fly said:

irishfield said:

has anyone else ever had this happen to you and is there any experience with or chance that my OFF/R/L/BOTH/START key switch was the culprit and the internals of the switch stayed connected to the start circuit even though I had turned it to both and actually all the way back to OFF and the starter would run when the master was turned on. Would hate to get my starter back on with a new remote starter relay and have this happen again if someone else on here has ever had the mag switch start postion stick I'd sure like to know. And yes I know many of you have seperate toggles/switches and a start button, but there are at least a few "reworked" panels and experimentals hanging around here.

Thanks,
Wayne

Click to expand...

Wayne...

Had it happen to me in a Bonanza once... Did the tractor fix and hit the solonoid with a screwdriver handle and started it again... Simple to wire an indicator light in the starter wire... Like you hadn't figured that out already!...

Click to expand...

Just wish I had of heard something before it spent 10 minutes running around with the flywheel. Guess it could have been worse as I could have rushed the warm up and been in the air! Good idea for a light hooked to the big feed line to the starter. This will let me know if it ever stays energized again. Maybe one on the switch lead for awhile this winter as well to see if the mag switch is the culprit!?

I had the same thing happen a few years ago with a B&C starter. I shut the engine off right away once I realized the starter was ingaged all the time. When I turned the master on the engine would turn over. Tapped the starter solenoid with a rubber mallet and it has worked fine ever since.

Before anyone else brings this one up, I had a PM asking if I have the diode on the start solenoid to go with the key start mag switch. Yes I do have the diode in place, but I guess I'd better put it to a meter and make sure it's still doing it's job ...before I tighten everything up on the new solenoid.

I had this problem on my cherokee six. It was a bad bendix switch.
Ken

Not exactly the same, but related problem.

I once had shorted P-lead in a C 182 caused by a 25 yr old mag/starter switch. Aluminum tracks had been made in the plastic contact carrier by the aluminum wiper element rubbing across the plastic. The tracks eventually contained enough metal to conduct between the contacts. After hunting the mag problem for hours, an experienced mechanic told me to disassemble the switch and clean the plastic with a pencil eraser. Worked fine ever since.

I suppose it could happen to the element that engages the starter solenoid as well as the mag element.

Steve

When Pigs Fly said:

Wayne...

Had it happen to me in a Bonanza once... Did the tractor fix and hit the solenoid with a screwdriver handle and started it again... Simple to wire an indicator light in the starter wire... Like you hadn't figured that out already!...

Click to expand...

Had it happen to me in a Bonanza once too....guess we just shouldn't try flying Bonanzas. Contacts were welded shut in that one, replaced the solenoid and diode.

I just had my starter solinoid weld itself 2 weeks ago. Battery was almost dead, tried to get two blades to start it, and nope. Then noticed that the prop was still trying to turn. Got one more blade, it started, so headed for the pumps. Looked at the voltmeter and noticed it showed 5.8v instead of twelve or better taxiing. Got to the pump, shut off, and the starter is humming. Turning the master off didn't kill it. Jumped out, propped it, back to the hanger for tools to pull the pos cable off. A friend said latter that a low battery will sometimes cause the solinoid's contacts to weld themselves. Yup. New battery and solinoid did the fix, no starter damage.

Wilbur

Always a GOOD idea to clear the prop area when turning on the Master Switch, even if you don't plan on starting the engine, just because of this possibility. I've seen it happen a few times over the years. Most pilots don't realize that it's possible to get that prop turning by just turning on the battery/master switch. Something I discuss with pilots on flight reviews. Off subject, but I just read an NTSB report about a gentleman propping his C-172 at the Nut Tree Airport here in Ca. Was the day after Christmas, they found him the next day in his truck, a trail of blood leading from the plane. Severe head injuries, and died a few days later...........again, as Dave says......ya awl be careful out there.
Brian

PS: We've installed a few hot starter warning lights in Bonazas over the years. Several years ago, the Bonanza Society magazine had an article on hot starters and recommended the light.

sjohnson said:

Not exactly the same, but related problem.

I once had shorted P-lead in a C 182 caused by a 25 yr old mag/starter switch. Aluminum tracks had been made in the plastic contact carrier by the aluminum wiper element rubbing across the plastic. The tracks eventually contained enough metal to conduct between the contacts. After hunting the mag problem for hours, an experienced mechanic told me to disassemble the switch and clean the plastic with a pencil eraser. Worked fine ever since.

I suppose it could happen to the element that engages the starter solenoid as well as the mag element.

Steve

Click to expand...

Thanks Steve and everyone else responding to this! Maybe I'll get my digital ohm meter out and play with the key switch as well to see if there are any traces of a closed circuit in the start positon. Wayne

The old mag switches would carbon track. Were notorious for being hot when in the off position, or intermittent in the off position. I believe there was an AD note years ago concerning the problem in the old style mag switches. First J-3 I ever flew had this problem.......we finally figured it out and got a new mag switch.....well maybe not new, but a different one LOL

Brian

For everyones information and future reference when your day for overhaul comes, I just got a call from the electric shop that I use to overhaul all my starter/alternators in the yard (tractor/bulldozer/backhoe etc) and he has my Skytec 12-122LS apart. This is the small compact version that is designated LS or PM (depending on the side you need the solenoid) from Skytec and not the high torque geared model that looks similar to the B&C starters. The electrical shop says it is just a Ford Permanent magnet - gear reduction starter installed into the fancy cast Skytec case. Apparently there are only two versions of this with one being used on most of the ford trucks and vans etc and then this oddball which has an extra tooth on one(or some) of the gears. All Parts are readily available.. bushings/gears etc (everything but the case he said!) to cheaply overhaul, so don't anyone go out and pay $354US for a new one when the day comes! I suspect from previous experience with this guy that I won't be out of pocket more than $85Cdn. Will let you know when I get the bill.

Wayne

Uh-oh. I can see it coming... The "Approved vs. Unapproved" ran... er, conversation.

I think that's a great find for the experimental folks. Thanks, Irishfield. Much as the thought of wasting cash tees me off though, I'd still have to insist on a part with a yellow tag on it.

See Ya'!

I needed an alternator for an O-540 years ago....I got the part number and called Wilson in Minneapolis. The guy told me he had those part numbers in stock but couldn't sell them to me because it was an aircraft part number..........but he did say he could sell them in Canada.........so I called a buddy up there and had him order one for me. It was a third of the cost as an aviation parts supplier here in the US.
Can someone tell me the reasoning behind that? Is is all strictly a matter of paperwork? The part is identical.....no extra testing......no quality difference. Whazzzup??

cubdrvr said:

I needed an alternator for an O-540 years ago....I got the part number and called Wilson in Minneapolis. The guy told me he had those part numbers in stock but couldn't sell them to me because it was an aircraft part number..........but he did say he could sell them in Canada.........so I called a buddy up there and had him order one for me. It was a third of the cost as an aviation parts supplier here in the US.
Can someone tell me the reasoning behind that? Is is all strictly a matter of paperwork? The part is identical.....no extra testing......no quality difference. Whazzzup??

Click to expand...

Maybe the Canadian part didn't include dealer prep and delivery charge, void where prohibited by law... And the FAA fee...

Eddy Current said:

Uh-oh. I can see it coming... The "Approved vs. Unapproved" ran... er, conversation.

I think that's a great find for the experimental folks. Thanks, Irishfield. Much as the thought of wasting cash tees me off though, I'd still have to insist on a part with a yellow tag on it.

See Ya'!

Click to expand...

I hear yah "Eddy", but he isn't putting anything in there that wasn't there before. This guy has been doing this work for 20+ years and he took over from his dad that is still in the shop and in his 80's. The internals of these Skytec's is Ford equipment..not similar..it is Ford wrapped up in a new casting to fit the lyco and approved by the FAA!

We've had enough R&R around here to last a long time...just offering an alternative to those that can consciously or legally take it!

Cheers,
Wayne

Agreed. I can understand the reasoning for alternators, due to brush density and arcing at altitude, etc. But since the difference in altitude between the starter on the cub you're going to fly and the starter on the truck that got you to the airport is about three feet, that can't be it.

Any higher level of QA or inspection required for parts used in aircraft will not improve safety in flight in this case. A failure is still unlikely. If it does fail, you're just going to have to find someone to prop you or wait 'till you can replace the starter.

So the difference is all bureaucratic. In A&P school the "Black & White" attitude of "Approved parts only!" is getting drilled into me. I know what I need to do to get through class, but when I'm done and tested and certified and working, What is realistic/acceptable?

In response to Eddy's question: An intelligent question for discussion at your A&P school with your instructors.

Approved parts, Owner-produced parts, Servicable parts. All have definitions.

The answer to your question above is "approved parts".

The starter internals here that Irishfield is discussing are intended to go on his experimental aircraft.

I have accessory shops with CRS rebuild/repair the accessories which I intend to install on certificated a/c.

This doesn't seem to be a "gray" area at all.........But it's perfectly reasonable for an experimental.

UPDATE on the starter overhaul ! REMEMBER that I'm running an Experimental and allowed to do this .... and have been offering this informaton based on that for those that can use this information legally or consciously!!

Picked up my overhauled 12-122LS Skytec starter today! Huge bill of $72cdn + tax. $40 labour/$18 for new drive and $14 for a set of brushes. Sure alot better than the $354US + shipping for a new one!

Anyone interested ...for reference the drive # is 1.01.0623.1 ...but of course I don't know from whom, but your rebuilder would probably recognize the #/supplier and the fact that it's a Ford Permanent Magnet starter wrapped up inside a Skytec casting.

One interesting thing was found when bench testing the Skytec (and it's not something the overhaul caused ...as I have a 12-149PM here as well - brand new in box and it does the same thing!). With the jumper wire in place to auto engage the solenoid... when power is removed after the starter is up to speed ..the drive is slow to retract and doesn't really do so until the thing quits spinning and then it clicks back. Seems that the starter... while coasting to a stop makes enough power (or inductance) to back feed the solenoid and hold it out. If you remove the jumper and use it to pull the solenoid in and disconnect it to shut down, the drive snaps back immediately while still spinning.... as you have removed the coil from this "feed back".

Starting to think it might be a good idea to remove the jumper and bring power direct to both the remote solenoid and the starter solenoid lugs. Then use the start switch circuit that pulls in the remote solenoid as it was (since the existing switch/CB/wire can't handle the 35A-50millisecond spike of the starter solenoid) except that instead of the high load output from this remote solenoid feeding the high load lug on the starter..fed the internal solenoid input on the starter from it with a #10 wire to get the quick snap back on the drive to lessen the chances of it staying out on the ring gear. This will leave the ability to "idiot light" the remote output wire that feeds the starter solenoid so if the remote contactor ever welds I will know the starter is going to run. Unfortunately now that power is feed directly to the starts big lug... if the contactor in the starter solenoid itself welds together the starter will run steady once the master is turned on and the idiot light will not come on! Maybe forget the idiot light all together and just remember what High charging current - Low voltage reading means on the gauges next time. I'm sure I won't forget anytime soon!

All comments/advise/wives tails welcome!!

Thanks,
Wayne

Thanks Wayne.

There was a guy from SkyTec on the site a while back defending his product.

I wonder if he's still around or if he'd be interested in knowing about your findings of the "slow to retract drive"??

Also, he stated that no product (skytec) had any failures of the plastic (fiber-reinforced) internal parts to the starter. I have heard of several and experienced one. Did your rebuild guy notice anything with the "throw-out yoke"??(for lack of a better word).

Anyway, I wonder if he's still around here somewhere.

Big AK said:

Thanks Wayne.


Also, he stated that no product (skytec) had any failures of the plastic (fiber-reinforced) internal parts to the starter. I have heard of several and experienced one. Did your rebuild guy notice anything with the "throw-out yoke"??(for lack of a better word).

Click to expand...

Nothing noted as worn or wrong with the throw out yoke etc. I have no problems with plastic parts (considering I own a plastic injection moulding co and have even made things like seat belt locking mechanisms from plastic for TRW and Bendix) as long as the CORRECT ENGINEERING RESIN has been used!! Amazing what you can make from plastic >IF< you do it right. I didn't see the starter apart, but will make sure I do if there is a next time!

I also suspect this throw out yoke is also "stolen" from the Ford PM starter as well, so think of how many times a car gets started compared to an airplane and there really shouldn't be an issue.

Wayne

irishfield said:

...With the jumper wire in place to auto engage the solenoid... when power is removed after the starter is up to speed ..the drive is slow to retract and doesn't really do so until the thing quits spinning and then it clicks back. Seems that the starter... while coasting to a stop makes enough power (or inductance) to back feed the solenoid and hold it out. If you remove the jumper and use it to pull the solenoid in and disconnect it to shut down, the drive snaps back immediately while still spinning.... as you have removed the coil from this "feed back".

Click to expand...

My mind is bending in pretzels trying to think of which way the current will flow with the motor connected to solenoid (via the jumper), but I'm guessing a snubber diode (reverse biased from the jumper to ground) would help. It might need to be a big diode, though, since it has to dissipate the energy stored in the motor windings as well as the solenoid windings. Maybe two or three 1N4003s in parallel would work if a one alone won't.

Regards,
Steve

sjohnson said:

irishfield said:

...With the jumper wire in place to auto engage the solenoid... when power is removed after the starter is up to speed ..the drive is slow to retract and doesn't really do so until the thing quits spinning and then it clicks back. Seems that the starter... while coasting to a stop makes enough power (or inductance) to back feed the solenoid and hold it out. If you remove the jumper and use it to pull the solenoid in and disconnect it to shut down, the drive snaps back immediately while still spinning.... as you have removed the coil from this "feed back".

Click to expand...

My mind is bending in pretzels trying to think of which way the current will flow with the motor connected to solenoid (via the jumper), but I'm guessing a snubber diode (reverse biased from the jumper to ground) would help. It might need to be a big diode, though, since it has to dissipate the energy stored in the motor windings as well as the solenoid windings. Maybe two or three 1N4003s in parallel would work if a one alone won't.

Regards,
Steve

Click to expand...

Thanks Steve! Got some of those somewhere in a parts cabinet. Still have the starter/remote solenoid etc all bolted and cabled together (simulating A/C installation) on the bench. To be -24*C tomorrow anyhow so not going to freeze my fingers trying to install .....so may as well play and see how the diodes work out

Wayne

Wayne,
Now I've almost (but not quite) convinced myself it won't work. That's the problem with theory. A few minutes with an oscilloscope would sort this right out.

Skytec says it's normal for the starter to stay engaged for .5 to 2 seconds, "... a permanent magnet motor will actually provide power to itself as it winds-down and will keep the starter drive engaged for about a half-second until it loses sufficient RPM to fully disengage."

Their RPM theory doesn't quite hold up, since the motor can't slow down while engaged to a ring gear. It actually speeds up as the engine starts. If the starter were a good enough generator, the starter would stay engaged. So, it seems that the solenoid field is collapsing even when the starter acts as a generator. The diode may provide a current path to collapse the field faster. The starter just slows the process down.

Note that your bench setup doesn't simulate the ring gear turning the starter, so results may differ on the airplane.

Let us know how it turns out.

Thanks,
Steve

Guess the only thing I'll really be looking for with diodes in place is an immediate snap back of the drive just like happens if I don't have the jumper in place. This will tell me it will work. Little slow getting going today, so may not have results till tomorrow.

Wayne

Threw some diodes from the jumper/solenid coil input to ground. Has absolutely no effect...unless of course you try to remind yourself of what you learned 20 years ago in electronics lab and put them in backwards. Then they explode really nicely !! Watch the fingers!

However....if you put between the main load lug and the solenoid coil input (with the cathode end attached to the coil) it speeds up the drive retraction. For the test I used five x 1N4006's in parrallel. Retraction time is about 1/2 it is with the jumper in place. IE: run starter up to full speed..remove power and it takes about 4 seconds for it to quit spinning. Without the jumper wire installed retraction is immediate upon removing the power, while the drive is still spinning. With the diodes in place it takes 2 seconds for retraction, while the drive is still spinning. With the jumper in place retraction happens at 4 seconds and when the unit has completely stopped spinning.

Ran the starter for almost 30 seconds to make sure the diodes didn't heat up or blow and they seem fine, but I'm still going to sleep on it to decide whether to bother installing the diodes...considering I have been starting this thing for almost 4 years with this starter as it is!!

irishfield said:

...if you put between the main load lug and the solenoid coil input (with the cathode end attached to the coil) it speeds up the drive retraction.

Click to expand...

Well, that's unexpected. Whatever works. I wonder what would happen if both sets of diodes were in place. This would probably be too complicated and fragile for actual use.

Steve

Wayne

Whew, you guys are way over my head. But to simplify this, should I go out and buy a Ford starter for my experimental cub or do I need the external casting for mounting points etc? I understand the guts are the same but what about the outside? What about weight?

Thanks

Bill

Bill Rusk said:

Wayne

Whew, you guys are way over my head. But to simplify this, should I go out and buy a Ford starter for my experimental cub or do I need the external casting for mounting points etc? I understand the guts are the same but what about the outside? What about weight?

Thanks

Bill

Click to expand...

No Bill! The casing is indeed Skytec's own casting for mounting to the Lycosaurous. It's just the internal workings that are "stolen" from Ford.

Cheers,
Wayne