Inadvertant starter engagement
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
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David Bengtson
- Posts: 20
- Joined: Mon May 17, 2004 12:54 am
Inadvertant starter engagement
I am a new owner of a 1956 Cessna 170B, also new member of The Association. While practicing take offs and landings yesterday I did something stupid!! I pulled the starter engage knob instead of carburetor heat. The starter was engaged for a few seconds before I realized what I had done. After landing and shutdown I engaged the stater and it seems to operate normally. Has this happened before and what are the usual results? Thankx for anyones info. David Bengtson no.7734
NOISY CARB HEAT!
I BET IT DIDN'T TAKE LONG FOR YOU TO LET THAT SUCKER GO! YOU WOULD HAVE A HARD TIME CONFUSING MY STARTER PULL WITH CARB HEAT FOR THAT SPRING IS VERY STRONG. AND IT IS WAY OVER TO THE RIGHT SIDE OF THE ROW OF PULL KNOBS. YOUR ACCIDENTAL ENGAGEMENT OF THE STARTER COULD HAVE BEEN MUCH WORSE. THE RING GEAR IS A VERY COSTLY ITEM AND IT MAY HAVE SUSTAINED SOME DAMAGE. CHECK ALL ROUND FOR ANY DAMAGE ON THOSE GEAR TEETH.
ALSO REMEMBER, COCKPIT FAMILIARIZATION IS A VERY IMPORTANT ELEMENT IN BEING A PROFICIENT PILOT. KNOW WHERE EVERYTHING IS BEFORE JERKING ON IT!
ALSO REMEMBER, COCKPIT FAMILIARIZATION IS A VERY IMPORTANT ELEMENT IN BEING A PROFICIENT PILOT. KNOW WHERE EVERYTHING IS BEFORE JERKING ON IT!
OLE GAR SEZ - 4 Boats, 4 Planes, 4 houses. I've got to quit collecting!
David are you certain the starter was actually engaged? Or did you simply pull the knob out a little bit before you noticed what you'd done? (Most of the pull-starters require quite a bit of tug at the end of their travel before they actually engage the starter...much more than a simple carb heat application.)
The starter-drive adaptor is a large gear connected to a small gear by a short cylinder that has 3 (or 5 if you have the latest version) rollers inside it. As the starter motor spins up, it drives those rollers up small internal ramps and pressure/friction build until the cylinder ends are jammed with the rollers. Then the spinning big gear imparts a spin to the little gear which was engaged with the engine's ring-gear by the pull-cable. Ole Gar (FlyGuy) is correct that the ring gear can be damaged by the episode, but unless you heard quite a racket in flight it's unlikely they actually engaged.
It's easy to check. There's only 5 studs to undo (and the power cable) to remove the starter and look at the start-adaptor and the ring gear. If your sure you actually engaged the starter in flight you should also drain your oil and look at the pressure screen (the one with the oil temp probe in it) and/or cut open your spin on filter if you have one, to look for metal from the gears.
I'll bet you didn't really get it engaged however, because the distance (and the effort) you have to pull that starter versus the distance you normally have to pull that carb heat are so different that I think you'd have noticed before you actually got it engaged.
The starter-drive adaptor is a large gear connected to a small gear by a short cylinder that has 3 (or 5 if you have the latest version) rollers inside it. As the starter motor spins up, it drives those rollers up small internal ramps and pressure/friction build until the cylinder ends are jammed with the rollers. Then the spinning big gear imparts a spin to the little gear which was engaged with the engine's ring-gear by the pull-cable. Ole Gar (FlyGuy) is correct that the ring gear can be damaged by the episode, but unless you heard quite a racket in flight it's unlikely they actually engaged.
It's easy to check. There's only 5 studs to undo (and the power cable) to remove the starter and look at the start-adaptor and the ring gear. If your sure you actually engaged the starter in flight you should also drain your oil and look at the pressure screen (the one with the oil temp probe in it) and/or cut open your spin on filter if you have one, to look for metal from the gears.
I'll bet you didn't really get it engaged however, because the distance (and the effort) you have to pull that starter versus the distance you normally have to pull that carb heat are so different that I think you'd have noticed before you actually got it engaged.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Dave, what I did in mine was to mark the starter knob with a circle of red tape.( I wanted to get a small skull decal but couldn't find one).Even better would be a T-handle starter cable,to tactilely differentiate it from all the other knobs. Til you get used to the airplane,eyeball everything twice before you pull it.
Example:on my first solo in a 152 years ago,I was midfield downwind to land when I pulled the mixture all the way out instead of the carb heat. Wow! What a rush! The engine never really died as it only took a second to figure out & correct ( took a little longer to clean the upholstery later!), but I learned a pretty good lesson.
If you do pull the starter off to check for damage,or even if you don't,be sure the starter cable & lever are adjusted as per instructions to avoid damaging the parts by inadvertant or improper starter engagement. I believe they're in The 170 Book,or maybe the SRAM book. Or maybe you can get a copy from one of the starter-clutch vendors.
Maybe someone who's handier with a computer than me could cut & paste (or whatever) the adjustment instructions here,or somewhere on this website?
Eric
Example:on my first solo in a 152 years ago,I was midfield downwind to land when I pulled the mixture all the way out instead of the carb heat. Wow! What a rush! The engine never really died as it only took a second to figure out & correct ( took a little longer to clean the upholstery later!), but I learned a pretty good lesson.
If you do pull the starter off to check for damage,or even if you don't,be sure the starter cable & lever are adjusted as per instructions to avoid damaging the parts by inadvertant or improper starter engagement. I believe they're in The 170 Book,or maybe the SRAM book. Or maybe you can get a copy from one of the starter-clutch vendors.
Maybe someone who's handier with a computer than me could cut & paste (or whatever) the adjustment instructions here,or somewhere on this website?
Eric
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Bruce Fenstermacher
- Posts: 10318
- Joined: Tue Apr 23, 2002 11:24 am
Close...but no cigar. The starter lever should compress the starter pinion gear 7/16" before it CONTACTS the starter switch button. The remaining 1/8" is used closing the switch, ...with total travel about 9/16". This is all AT the STARTER SHIFT LEVER ...somewhat more movement actually occurs inside the cockpit via the cable.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
I adjusted mine per the instructions. It's not too easy,especially for a newby,to do it right just by reading the above (well-intentioned) posts. The full description of adjustments,including illustrations, really is a lot easier to understand. You know, "a picture's worth a thousand words...."
I just flipped thru m SRAM book & my 170 Book,didn't find any good instructions. The SRAM book had a half-assed diagram.
I bought my starter clutch from Niagra Air Parts,it came with a nice easily-understandable instruction sheet. Maybe they'll send you one if you ask nice,Dave.
http://www.niagraairparts.com
sales@niagraairparts.com
800-565-4268 or 705-326-1368.
Eric
I just flipped thru m SRAM book & my 170 Book,didn't find any good instructions. The SRAM book had a half-assed diagram.
I bought my starter clutch from Niagra Air Parts,it came with a nice easily-understandable instruction sheet. Maybe they'll send you one if you ask nice,Dave.
http://www.niagraairparts.com
sales@niagraairparts.com
800-565-4268 or 705-326-1368.
Eric