November 29th 05, 04:38 PM
Hey all... I posted about a year ago about "residual engagement" on a Skytec
starter for my Cherokee 180. At that time, I discovered the poor way that they wired
it for certified aircraft use. Using the alternate wiring (for experimental only)
http://www.skytecair.com/Wiring_diag.htm, this backEMF driving the solenoid could be
eliminated. Since this would require alteration of aircraft wiring, PMA'ing the unit
would be difficult.
NOW, I've run into another problem with my plane. Recently, it has become
harder to start. I had some chipped teeth in the ring gear from awhile back, so I was
just assuming it was finally wearing out. Over the past couple of flights, it will
often "give up" on a compresison stroke and you can hear the starter just "whizz." I
called Skytec and they dismissed my theories that:
- Remaining engaged for a second or so is hard on the ring gear.
- I should try to rewire the system so it cannot do that.
- A broken tooth off the ring gear is causing the dead spot... rather the starter
should be sent back to them for measurement and verification of the sprag clutch and
housing.
Anyone else experience this? I must admit that I was rather put off by the
customer service guy on the phone. His attitude was, "We've got tens of thousands of
these in service, so your problem cannot be due to bad design." Then he went on to
say that a kickback can break the sprag clutch, bend the shaft, or bend the housing,
and that free-wheeling gears after starting is harmless. *Any* design (good or
bad) can stand improvement... especially when regulations limit the design process. I
would imagine that the checkup on our starter won't be covered by warranty either
since it's over 1 year old.
-Cory
--
************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************
starter for my Cherokee 180. At that time, I discovered the poor way that they wired
it for certified aircraft use. Using the alternate wiring (for experimental only)
http://www.skytecair.com/Wiring_diag.htm, this backEMF driving the solenoid could be
eliminated. Since this would require alteration of aircraft wiring, PMA'ing the unit
would be difficult.
NOW, I've run into another problem with my plane. Recently, it has become
harder to start. I had some chipped teeth in the ring gear from awhile back, so I was
just assuming it was finally wearing out. Over the past couple of flights, it will
often "give up" on a compresison stroke and you can hear the starter just "whizz." I
called Skytec and they dismissed my theories that:
- Remaining engaged for a second or so is hard on the ring gear.
- I should try to rewire the system so it cannot do that.
- A broken tooth off the ring gear is causing the dead spot... rather the starter
should be sent back to them for measurement and verification of the sprag clutch and
housing.
Anyone else experience this? I must admit that I was rather put off by the
customer service guy on the phone. His attitude was, "We've got tens of thousands of
these in service, so your problem cannot be due to bad design." Then he went on to
say that a kickback can break the sprag clutch, bend the shaft, or bend the housing,
and that free-wheeling gears after starting is harmless. *Any* design (good or
bad) can stand improvement... especially when regulations limit the design process. I
would imagine that the checkup on our starter won't be covered by warranty either
since it's over 1 year old.
-Cory
--
************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************