Bob & Ron's vintage Link Trainer (aka Blue Box) restoration adventures
We have been working on our aileron valves. The primary problems involve old gummy lubrication which caused them to be stiff, dirty dry linkage, and cracked hoses. We removed the valves, disassembled them, cleaned the old dirt and grease off, then lubricated them with gun oil. We replaced worn and cracked hoses. The aileron valve moves smoothly now.
Check out the Aileron valve section under Restoration hints for more info.
Here is a tinted postcard of the Link Trainer Building at Napier Field, Dothan, Alabama. Napier Field was built as a military base during World War II. The postcard description is ‘ “Learning to fly by not flying” these Cadets and their Instructors are busily engaged in piloting Link Trainers to a successful landing by the use of instruments only.’ It was published by Dothan Cigar & Candy Company.
Notice the light horizontal streaks on the floor? Likely a photo touch-up covering the large cables between the trainer and the instructor’s console.
We removed our Esp’s rudder valve, cleaned and lubricated it. See the “Rudder Valve” section under “Restoration Hints” for details. What a difference. The valve sections were gummy, and now easily move smoothly.
When we connected up the ANT-18’s instructor’s air speed indicator, the cockpit air speed indicator stopped working. We traced the problem to the instructor’s instrument having a stuck pointer. The Telegon instruments are all similar. The only difference between a transmitter and an instrument (i.e. receiver) is that the angular position of the Telegon motor is mechanically driven by the transmitter’s internal mechanism, but the instruments’ Telegon motors are free to rotate and align to the transmitter’s sine and cosine fields. Since our instructor’s station pointer is frozen, it is acting like a second Telegon transmitter locked into its current position. The two “transmitters” fight each other and the cockpit instrument stops working.
We pulled the instructor’s air speed instrument; it is up next for repair.
Meanwhile, back to our first altimeter which did not work. We disassembled it down to the Telegon motor. When we first disassembled the unit, it took noticeable force to move the instrument pointer. After turning the pointer by hand a few turns, it freed up the shaft, and now spins easily. We cleaned up the parts, slip rings, contacts, etc., and oiled the pin bearings with clock oil. We tested the Telegon motor with our instrument tester, and the motor now works just fine. We are hoping to reassemble and retest the repaired instrument soon. Fingers crossed!
Last week we got our first two cockpit instruments to work and roughly calibrated in the ANT-18. After restoring the two regulator bellows and replacing a good bit of bad vacuum hose, our cockpit engine RPM and air speed instruments started to work. Yea! Both instruments respond to throttle, and the air speed decreases in a climb. When we connect up the instructor’s air speed instrument, the cockpit air speed instrument unfortunately stops working – so we’ve got some troubleshooting to do.