Center Stack Radios / 172 Control Column
Posted: Sat Apr 21, 2018 11:09 pm
What did I Buy for my 170A this week or rather what did I decide to do to my 170A/210 HP airplane?
Center stack radios. Say it isn’t so. Well as modified airplanes go I have nothing to lose except AMU’s (Aircraft Monetary Units) $$$$. With 210 Horse Power, Constant speed 80 inch prop and 180 landing gear, battery in the back behind the baggage what is left to keep original? I have already removed the piano key’s and installed a Garmin G5 and circuit breakers. And other modern radios. Did they even have Radios in 1950. Well of course they did my dad was an amateur radio operator, I saw and operated the radios. I even learned Morse code, I use a android smart phone today.
I purchased a 1997 172R Y/U control yoke removed from a wrecked Cessna from the bay with the pully’s, cables and control yoke shafts. I have disassembled and inspected all parts and ordered a couple of new bushings / bearings and one new cable for the control column that did not pass inspection. I also Purchased a 1965 Cessna 175 T control similar dimensionally to the T control installed in the 170’s. The reason for that is I do not have to ground my airplane while I build up the parts. For now, I plan to keep the old control yokes.
I am also purchasing Del Airs STC now $2800 in 2018 AMU’s. I will send both control yokes to Chris at Del Air. What I will get back for the $2800 is a new instrument panel blank that I can configure any way I like. And the 1997 Y/U control yoke with the bottom of the 175’ control yoke welded to it. And the STC paperwork. The old instrument panel gets drilled out and the new one gets riveted or screwed in.
The critical dimension is the pivot at the airframe to the control rod at the bottom of the column. In the 170’s that dimension is 3 &1/2 inches. In the late 172s with center stack radios that dimension is 4 & 1/8 inches. Which is why the 172 Y/U control column cannot be used as is.
The original aileron direct cables will not work as they will be the wrong length and have the wrong ends to connect to the turn barrels at the revised 172 Y/U cable connections. Which are both left hand MS21259-4LH cable ends. These will need to be swaged onto the original Aileron direct cables. It is authorized to splice the cables with nicopress sleeves and would be easy to accomplish but this is sloppy way to go about it for me. And I have the tool required to install and swage the MS21259-4LH cable ends. Which will make it look like a factory installation. I will end up with two sets of cables, the original which will serve as mockups and the new stainless cables which will get installed as permanent after testing.
When the 175 control column gets here I will add pictures showing the differences between the two.
I have done this all before on my friends 172 Tail dragger or rather he did it and I was the IA signing it off. He had to have his field approved by the FAA as an Avion modification (Not doable according to my FAA Principle Maintenance Inspector in this day and age). I am still not sure if Avion has an STC for this mod. But for me Chris at Del Air is the man to do business with.
Regards,
Jim
Center stack radios. Say it isn’t so. Well as modified airplanes go I have nothing to lose except AMU’s (Aircraft Monetary Units) $$$$. With 210 Horse Power, Constant speed 80 inch prop and 180 landing gear, battery in the back behind the baggage what is left to keep original? I have already removed the piano key’s and installed a Garmin G5 and circuit breakers. And other modern radios. Did they even have Radios in 1950. Well of course they did my dad was an amateur radio operator, I saw and operated the radios. I even learned Morse code, I use a android smart phone today.
I purchased a 1997 172R Y/U control yoke removed from a wrecked Cessna from the bay with the pully’s, cables and control yoke shafts. I have disassembled and inspected all parts and ordered a couple of new bushings / bearings and one new cable for the control column that did not pass inspection. I also Purchased a 1965 Cessna 175 T control similar dimensionally to the T control installed in the 170’s. The reason for that is I do not have to ground my airplane while I build up the parts. For now, I plan to keep the old control yokes.
I am also purchasing Del Airs STC now $2800 in 2018 AMU’s. I will send both control yokes to Chris at Del Air. What I will get back for the $2800 is a new instrument panel blank that I can configure any way I like. And the 1997 Y/U control yoke with the bottom of the 175’ control yoke welded to it. And the STC paperwork. The old instrument panel gets drilled out and the new one gets riveted or screwed in.
The critical dimension is the pivot at the airframe to the control rod at the bottom of the column. In the 170’s that dimension is 3 &1/2 inches. In the late 172s with center stack radios that dimension is 4 & 1/8 inches. Which is why the 172 Y/U control column cannot be used as is.
The original aileron direct cables will not work as they will be the wrong length and have the wrong ends to connect to the turn barrels at the revised 172 Y/U cable connections. Which are both left hand MS21259-4LH cable ends. These will need to be swaged onto the original Aileron direct cables. It is authorized to splice the cables with nicopress sleeves and would be easy to accomplish but this is sloppy way to go about it for me. And I have the tool required to install and swage the MS21259-4LH cable ends. Which will make it look like a factory installation. I will end up with two sets of cables, the original which will serve as mockups and the new stainless cables which will get installed as permanent after testing.
When the 175 control column gets here I will add pictures showing the differences between the two.
I have done this all before on my friends 172 Tail dragger or rather he did it and I was the IA signing it off. He had to have his field approved by the FAA as an Avion modification (Not doable according to my FAA Principle Maintenance Inspector in this day and age). I am still not sure if Avion has an STC for this mod. But for me Chris at Del Air is the man to do business with.
Regards,
Jim