Panel Upgrade

[ptporebski]

Hello Everyone,

I have a 1959 C-172 that I bought in June 2009. At the first annual I found a couple of items - mud dauber wasp nests all over the place, corrosion at the cowl/firewall lap joint, cracked spinner backing plate, and an unairworthy prop. Oh well, except for the prop nothing expensive. After posting here and extensively searching I was unable to find an eight hole prop for the O-300A engine so I have ordered a new one from Leading Edge in MT.

I also did a couple of upgrades. Added a Whelen strobe system, changed the nose gear strut which was badly chewed up. I need to thank one of our members, Dean Zinter, who graciously sold me his now un-needed nose gear strut after he converted to a C-170C. I also modified my floating instrument panel. I wanted to arrange the flight instruments into the standard six pack configuration. I also bought a new DG and had my AI overhauled (both by SigmaTek). I also mounted my new Garmin Aera 560 in a Gizmo mount. Doing this required several iterations that I had made out of plexiglas to facilitate clearance checks. I drew the panel on AutoCad so changes are easy. I was surprised how much engineering effort this took. Some of the clearances are 1/16" to make things fit. Here are the prototypes I made:

And here is the completed panel:

I also had an issue with low vacuum prior to this upgrade. The old system (two 9" venturis) could not generate more than 2" of vacuum. After my AI & I leak checked/tested the system, I ordered two new 9" venturis from Aircraft Spruce. When they came in they had a spun flange on the downstream end. I cut off the flange as I concluded it served no purpose. I was correct; the system now pulls too much vacuum and I have installed a Rapco vacuum regulator to solve that. Now, Voila! A modern layout for an old airplane that works!

[GAHorn]

That's a nice setup, and the use of acrylic for fitment/tests is a great idea. Clearly (wink) his took a lot of effort.

The AN 5807-1 Venturi design is an approved design. The lower-flange shapes discharge-air preventing turbulence within the tube, as well as to strengthen the outer-tube against deformation. I doubt you'll get a condition-tag for your alteration but you should be aware if it alters the venturi from it's approved design....

Correction of the vacuum system defects often result in the need for a vacuum relief valve as depicted in the Cessna instrument installation drawings, where the valve is in the list of required items.

[Bruce Fenstermacher]

And an article with those pictures for our print publications would be GREATLY appreciated. Doesn't have to me complicated but maybe a few more details.

[ptporebski]

Bruce,

It's a straight tail 172 not a 170 so I assumed that the Assoc wouldn't be interested in an article. Besides, the guys will rib me to death about that funny looking wheel on the wrong end of the plane! :

But, if the Association is interested, I don't mind writing up something. After all the annual/upgrade/fixes only took me about 16 months for everything...

[wingnut]

What tool/tooling did you use to cut the holes in the 'plexiglass'? Is it acrylic, or lexan, or??? Inquiring mechanic want's to know. Thanks

[Bruce Fenstermacher]

Bruce,

It's a straight tail 172 not a 170 so I assumed that the Assoc wouldn't be interested in an article. Besides, the guys will rib me to death about that funny looking wheel on the wrong end of the plane! :

But, if the Association is interested, I don't mind writing up something. After all the annual/upgrade/fixes only took me about 16 months for everything...

Funny thing is I could tell from your description or photos what aircraft you owned. So it is applicable and appropriate for our 170s and would be an interest to members.

[N2255D]

Hello Everyone,

I have a 1959 C-172 that I bought in June 2009.

Way ahead of you Bruce. I could tell what airplane he had by the end of the first sentence in the first post.

[GAHorn]

Hello Everyone,

I have a 1959 C-172 that I bought in June 2009.

Way ahead of you Bruce. I could tell what airplane he had by the end of the first sentence in the first post.

Some days Bruce and I eat chicken.
Other days -feathers.

[Bruce Fenstermacher]

To be honest I was only looking at the pretty pictures.

[ptporebski]

Del,

The prototypes are acrylic. Cut using a waterjet. Yes, had a problem with the acrylic chipping, but not too bad. The chipping/blowouts were unsightly and would have been unacceptable for anything other than fixturing/clearance checking. As I provided an AutoCad file the shop charge for cutting my acrylic sheet 1/8" thick was $35.

I flew the plane extensively last week and have decided to modify the panel. I want to get my instrument rating. However, I am 6'-2" and installed the Fiberlite system which recesses the instruments. My viewing for the VOR is such that I cannot see the radial I am on. I have to back calculate the radial from the opposite radial on the bottom of the dial. Since I am a math challenged engineer I have problems doing this and flying the plane at the same time .

I'm thinking of swapping the GPS and the VOR & tach. Put the VOR on the top, GPS underneath it. I purchased a yellow-tag King KX-155 with glide slope and King-209 GS indicator that I want to mount. I'll remove the working KX-170 radio that is comm 2 and replace it with the KX-155. Would like to keep the Narco VOR indicator too. But to do that I will have to get rid of the 3-1/8" tach and go to a 2-1/4" tach. I could either mount it in the spare space on the fixed panel (see picture) or re-arrange and cut a new panel. Currently, playing around with the AutoCad file to see what I can do. As I said earlier, I was surprised how complicated this got. It's crowded under those panels guys!!

[LBPilot82]

FAIR WARNING. The King 209 indicators can have the OBS knob on the lower right. Almost ALL other units have them on the lower left. I know because I installed a 209 with intentions on upgrading in the future if it ever dies (or if I decided EVERYTHING must be Garmin It's the only non garmin piece i've got). Now I have discovered the panel will have to be filled/welded/ regrinded... whatever it takes.... to fit a different one. No problems with it yet thank goodness!!!

Looking at your pictures, I see the knob on the lower left. Maybe it's a newer 209 than I purchased.