(An email from Joe Polsgrave to Bill Copeland who requested that I put the information on the "Page")
Warning from Joe Polsgrove: "Which flap accuator do you have?"
Hi Folks, I noticed in an earlier issue of the Link an article by
Reinhard Metz about the flap actuator supplied by EDI part 111-22-006-01. I made a mental note but did not evaluate the actuator as mine had been working OK for over two years. That is now history, my failure mode was not as might be anticipated, the motor threw a brush (which is a piece of carbon bonded to a copper strap), the strap then rode on the commutator for a few revolutions until the strap and commutator were mutually destroyed by arcing. The so-called motor was almost identical to ones sold by Radio-Shack for approximately three dollars.WAIT! This is not the real problem! When I disassembled the actuator, it was apparent the gearbox and motor had been lifted from a cordless screwdriver which was designed to run on much less than 12 volts.
WAIT! It gets worse! The push force (flaps down) can easily exceed 300 pounds dependent on airspeed and the entire load at least on my unit was dependent on ribbon of hot melt glue which is the only method of capture holding the gearbox/motor in that force direction. I cannot say if my unit is only a prototype, (no doubt Ulrich would sell anything), but if all of these are the same in the field, there is a real concern. If the glue should fail and it will as soon as aluminum and gearbox mystery metal corrosion lifts the bond or the temperature rises melting the glue, the flaps may flutter leading to serious consequences. In the flaps up- condition, the gearbox is constrained by the nosepiece and some rather small roll pins. I don't believe anyone should fly with this actuator.
The following comments (to Bill Copeland) are a later addition to Joe's remarks above.
Yes, by all means, put it on any and all web pages. Only this morning, I
noticed a Black and Decker cordless screwdriver (model SD2000) in my Dad's shop. The gearbox is identical as is the motor made by Johnson electronics and the unit is designed to run on three nicad batteries 3.6 volts!!!! These units are certain to fail on 12 volts which is actually closer to 14 volts with the alternator running. The intermittent use of the actuator is the only savior of he motor allowing it to cool between uses. I hope I never see any of the EDI folks again. Joe
Check is on the way via snail mail. Hope you had a good western
Oshkosh. Keep up the good work.Joe Polsgrove
Any questions or comments, forward to Joe @: BGEXPRESS@MCI2000.COM