Center Stack Radios / 172 Control Column

How to keep the Cessna 170 flying and airworthy.

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Metal Master
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Center Stack Radios / 172 Control Column

Post by Metal Master »

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
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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c170b53
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Re: Center Stack Radios / 172 Control Column

Post by c170b53 »

I was able to use all the stock cables but had to custom make the centre U cable to aileron direct cables. I like the ease of using cable barrel clips wherever I can. Just installed two new GTR 225’s, my old 340 audio panel and transponder which left me with about 5 inches of free space in the centre stack area. Would have liked the room to put in an Aera or similar. What will you try to fit Jim?
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
Metal Master
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

Initially I will just fit my KY97A com, audio panel and my old Narco Nav/Com, STX transponder and maybe a dock for my iFly 740B GPS. What I really looking forward to is getting the flight and engine instruments is a common sense location also I would like to install a second Garmin G5.
I might try to find a used Garmin 430 WAAS. I have spent so much money on the KY97A I may have well bought the Garmin three years ago. Hind sight is 20/20.
And I agree this is exactly what I am doing, custom make the center U cable to aileron direct cables. I like the ease of using cable barrel clips wherever I can!
Jim
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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c170b53
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Re: Center Stack Radios / 172 Control Column

Post by c170b53 »

Been there somewhat too! I also have a dead KY 97 that I should have thrown in the dumpster rather than having spent $600 into a repair. I removed a young ky 97 and kx-175 and went to the two new radio's so hopefully I don't have to rip things apart again for awhile. Always fun; during the radio install I had to rewire my lighting system and afterwards spent hours T/S my post lights. I'd still under my panel with a meter thinking I had mis-wired something if it wasn't for the one GE330 bulb out of 10 that wasn't burnt out :D :D
Jim McIntosh..
1953 C170B S/N 25656
02 K1200RS
Metal Master
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

Received the 175 Control column yesterday that I am going to use to have Del Air (Chris) modify for the center stack radio installation. I made a full size drawing last night of the differences with all of the pulleys' sprockets and connections to get an understanding of the changes and to later help me make an instrument layout and drawing for the new instrument panel.
Cessna 170A and 172 control column Comparison RS crop (3).jpg
I also received the new cable ends from Aircraft Spruce for modifying the 170A aileron direct cables.
I have got to get to works more comment later.
Jim
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
Metal Master
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

Pictured is the modified 1997 Cessna 172 control column as modified be Chris at Del-Air. Next to it is the old section of the original Cessna 172 control column. The 172 control column was cut down so that with the new lower section welded in, the dimension from the yoke shaft center line to the pivot where it mounts to the brackets in the Cessna 170A consul is exactly the same as it was with the original T column. Also now having had the lower section of a T column welded in, the dimension from the pivot to the bearing at the very bottom where the elevator push rod connects is also the same as the Cessna 170A.
Modified 172 control yoke for installation in 170A.jpg
The drawing behind the modified control column is allowing me to make dimensional comparisons and do an accurate layout of where the new radio stack and instrument locations will be.
That drawing has now been removed from the drawing board and a new drawing is being made to locate all of the cutouts.
New center stack Panel RS.jpg
Just added a new photo of the first panel fit for instruments. I wanted to get this done to allow precise fitting of the right side panel and radio stack. The right side panel is cut and is now waiting to have instrument and glove box fitting done.

In other news I just received a field approved 337 coordinated with the FAA Aircraft Certification office to install a Sportsman STOL leading edge kit. The kit and this panel will wait until this winter to be installed.
Jim
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
Metal Master
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

I have edited the previous post with a new picture and comment.
Jim
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
Metal Master
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

I had been asked abut my current panel mods and so am attaching this picture to show the current instrument panel.
Note the extra 2 1/8" instrument panel holes, Square cut out in upper overlay and lack of piano keys
Note the extra 2 1/8" instrument panel holes, Square cut out in upper overlay and lack of piano keys
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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ghostflyer
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Re: Center Stack Radios / 172 Control Column

Post by ghostflyer »

Firstly there seems enough room between the G5 and the original control column . So which G5 was fitted ?. The STC one or the experimental one. Looking at the legal sense which instruments had to remain? Due to the lack of overhaul components in my part of the world I am wanting to remove all vacuum driven instruments and fit a G5.
Metal Master
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

ghostflyer wrote:Firstly there seems enough room between the G5 and the original control column . So which G5 was fitted ?. The STC one or the experimental one. Looking at the legal sense which instruments had to remain? Due to the lack of overhaul components in my part of the world I am wanting to remove all vacuum driven instruments and fit a G5.
It is the certified G5 installed under an STC. It is only certified to replace the attitude instrument. Even though the G5 has both directional information, altitude altitude warning, V speed information, airspeed and slip skid ball. It is only authorized to replace the attitude indicator. So all other instruments are still required.
Garmin now has approved the installation of second G5 to act as those other GYRO instruments and I will replace those with a second G5, however I will probably keep the other instruments as Back up. I have never had a Directional Gyro so I am now Vacuumles in Seattle.
My motivation to install the G5 was because my artificial horizon had died and I was going to have to replace it or have it overhauled. The cost of which approached the 1/2 price of the G5 without having all of the other features of the G5. I did have to purchase a Garmin GPS antenna as I had no other GPS source. However I ended up not using the new GPS antenna as it turned out I came by one that was donated to me. So I now have a WAAS GPS antenna to use for a future installation.
Between the G5 and my I-Fly 740 B with Synthetic vision, I find that flying I only use the primary instruments as secondary and cross reference in my scan. all instruments agree and I have four airspeed sources and four altitude sources which are my standard airspeed indicator, Both Knots and MPH on my I-fly704B and altitude on my STX 165 combined encoder transponder.
Jim
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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GAHorn
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Re: Center Stack Radios / 172 Control Column

Post by GAHorn »

Metal Master wrote:... I have four airspeed sources and four altitude sources ... Jim
WOW! .... a FOUR-Hundred MPH, Forty-Thousand-Foot Altitude Cessna One~Seventy! :lol:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Metal Master
Posts: 526
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Re: Center Stack Radios / 172 Control Column

Post by Metal Master »

I have been away from this project for a while. And that is not good for any airplane. After my wife dying in 2017 and then having to evict someone from my duplex house which I have been trying to get ready to sell. Read I live in a 17-room house by myself which used to have 13 people living here. Retired in June 2019 and working on the house and this Covid 19 isolation has just about driven me nuts. Did not do anything for the first 1/4 of 2020. But the state decided my business is essential, so I have done a few annuals over the last two months.
But finally, I started feeling guilty about neglecting my own airplane. So being able to hang out at my hangar by myself is a blessing. So, I started back on getting my center stack radio installation completed. So far, I have gotten the Basic instrument panel completed, painted the circuit breaker panel installed less labeling. Now have left to get the wiring routed to the new instrument locations and get the panel final installed. But I must take a break today and tomorrow to visit with my new endocrinologist. My ole doc retired in December and today I am scheduled to do my biannual flight review. I have several 9 Whelen post lights that I had bought on e-bay for a very good price but wanted a few more and was doing an internet search when I came across these Superior Panel Technology Fiberoptic panel lights. They are STC'd for a huge number of aircraft as well as all models of 170s. Those EZ nuts in the phots get rid of the grass hopper type of instrument nuts which I have learned to hate.
So here are a few pictures for your view.
panel edit 2.jpg
SPT Resize 2.jpg
Painted panel re-size 2.jpg
Circuit breaker re-size 2.jpg
A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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