Tag: Blue Box

Insert gear ‘A’ into bearing ‘B’

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.

Disassembled Kollsman altimeter.

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!

 

Red-letter day

RPM and Air Speed are first working instruments in ANT-18.

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. 

More speed Scotty

With the main bellows now rolling and pitching, we were hoping to get the ANT-18 off the ground.  But, with full throttle, we have no air speed, and no engine RPM.  We checked wiring to the primary instruments, cleaned the slip ring contacts, and various connector contacts till we got continuity.  Since the RPM cockpit instrument is operated pneumatically directly from the tachometer regulator bellows, we thought that was a good place to start troubleshooting.  That eliminated wiring and Telegon instruments as a potential problem, and let us concentrate on vacuum and linkage.  Our tachometer regulator bellows was very stiff.  We decided to restore both regulator bellows and the stall bellows since they were all stiff, and all related to air speed or engine RPM.

Outside of regulator bellows during restoration.

Straighten up and fly right

With vacuum applied to our newly refinished bellows, our ANT-18 was leaning badly to the left (or as our Navy buddy Jeff said “it is listing to port”).  We had to keep the yoke’s wheel at about 45 degrees to the right to counteract it.  After fixing all the leaks in the aileron pneumatics that we could find, we decided to adjust the aileron valve.  It took only a tiny adjustment of the torque linkage that goes to the center leaf of the aileron valve to correct the problem. 

While looking for aileron pneumatic leaks, we also restored the ANT-18’s rough air system.  Its key valves were leaking badly. 

What is a Jiggley ?

Here is a Link Trainer “Jiggley” action trading card.  After the bubble gum is gone, you have this great toy.  Jiggleys were made by the Model Airplane Company, Brooklyn, NY in 1950 and 1951.  They made several series of trading cards; Military, Cowboys, Circus, Weapons, Guns, etc.  Ours is No 45 from the Military Series 6  “Jiggleys”. 

Front of Link Trainer “Jiggley” trading card.

The Blue Box and his instructor are die cut punch outs.  You remove the background stencil that you can use to trace more “Jiggleys”.  Once the stencil is removed, there are two narrow strips of card in the back that connect the Blue Box and instructor together, each with a staple.  See the rusted staple popping through the orange Blue Box base, and the instructor’s pants?  You hold the strips, and jiggle them left and right, to see the Blue Box fly and the instructor scold the cadet pilot with his finger.  Too much fun. 

Back of Link Trainer “Jiggley” trading card.

I thought it odd that the instructions said “Replace Stencil to Pitch, Trade, Collect.”  Why “Pitch”?  Then I remembered how, when we were kids, we used to “pitch” baseball cards at recess to see who could get closest to a line or land it to tilt against the side of the school building.  Winner takes loser’s card.  Wow — that was a long time ago.