The International Cessna^® 170 Association

I just purchased a '54 C170B. The DG does not work and can not be repaired. Because of where it sits in the panel, I need another DG with a short case; no longer than 4-3/4" from mounting holes to the rear of the case. The newer DG's are 5-1/2 to 6" and with fittings it interferes with the Yoke 'T' behind the panel. If anyone has a working short case DG and is willing to sell it, Please let me know. Also the width has to be the normal 3-1/4". If I cannot find one, I will have to relocate several instruments an re-plumb the vacuum system to be able to install a newer longer DG.

What make and model do you presently have?...and have you tried to exchange it?

The DG Model is Cessna Model # 661053-0101. Mfg # ANS-20(W). The whole story is - I sent the DG in to have it overhauled. They called me and said it was too old and they could not get parts any longer. I asked if they would take it in exchange for an overhauled DG. They said no to the exchange because of the age issue. Could I buy one outright? They did not have one with that short of a case. I called one of the salvage companies in my area. They had 2 working DG's, but both were too long. I found another unit at a local a/c instrument company, I even went there with my old unit to compare lengths. From the mounting holes back it was the same length; it did stick out forward of the mounting holes. That was not an issue. I bought it and they were going to overhaul it for me. When I received it; the face had been changed and the length now from the new mounting holes to the back was too long. Apparently the newer DG faces took the mounting holes from the protruding glass face and moved them forward to make it a flush face unit - pushing the case back behind the panel; too long to be of use to me.

When one of the previous owners rebuilt the instrument panel, he put the DG dead center low on the panel and it is directly in line with the vertical part of the control yoke "T". If I do have to end up swapping instruments because I cannot find a replacement; there is only one that I think is short enough to work in the DG hole, and I haven't verified that a longer DG would work in that hole.

Check with Lucky and crew at Air Salvage of Dallas 972-227-1111; 800-336-6399; cell 214-957-5774 or email www.asod.com.

Good hunting!

Can you swap it with another instrument and put it above the tee? I switched mine with the altimeter. The hole location for the DG (and pretty much everything else except the OBS and CHT/EGT) in the photo is in the stock location for a '55. I think 54's are pretty much the same?? The layout looks a bit awkward, but in 23 years this way I've gotten used to it; I've even flown IFR with this layout.

Time now for a Yoke change!

Those old Sperry DGs will keep running until the next ice age.

I took the one out of my plane for modern looking unit.

The thing is almost the size and weight of a bowling ball.

Thanks for the heads up about Air Salvage there in Texas. I will call them tomorrow. As for the swapping positions with other instruments - yes I probably can. I was hoping to make that the last resort, so I didn't have to re-plumb the vacuum lines. As for the Yoke change idea, I'm not quite sure what that meant. As I said previous, one of the past owners took the original panel off and put on a custom one-of-kind flat panel. When I pulled the panel out to get this DG out, I did notice the only other shot case instrument in the panel is the VSI just to the right of the DG. I have not looked back there again to see what might be behind the VSI that needed it to be a short case, if anything. That spot might work except it does move it out of my scan pattern.

What blueldr was referring to when he said it was time for a yoke change is removing your T yoke and replacing it with a Y yoke from a later model (1960's) C-172 yoke. This would then permit you to put in vrs panel gauges/avionics that wouldn't otherwise work due to the T yoke hitting the instruments/radio's, etc. A still better, and the real reason to make the change, is it allows you to then utilize the more modern center stack of avionics. There are quite a number of 170's around that have made this change and it really makes for a nice setup.

170C wrote:What blueldr was referring to when he said it was time for a yoke change is removing your T yoke and replacing it with a Y yoke from a later model (1960's) C-172 yoke. This would then permit you to put in vrs panel gauges/avionics that wouldn't otherwise work due to the T yoke hitting the instruments/radio's, etc. A still better, and the real reason to make the change, is it allows you to then utilize the more modern center stack of avionics. There are quite a number of 170's around that have made this change and it really makes for a nice setup.

Swapping out the T is not a simple operation. And then there are approvals for the project.

Wow, Thanks for that info. That was one I had not heard of. I will keep that in mind for future reference.

You might accomplish what I did when I needed another 1/4"... see my post about 2nd artificial horizon.
http://www.cessna170.org/forums/viewtop ... n&start=15


Read the entire (2-page) thread to see how I did it:

http://www.cessna170.org/forums/viewtop ... nd+horizon

Aryana wrote:Avion here in CA has an STC for the swap from the T to the U:

http://www.avion.com/Products/Instrumen ... lAssy.html

Del-Air also has an STC for the "U" style yoke conversion.

Thanks for another great idea.

Changing to the "U" yoke is normally reserved for completely re-doing a panel to accomodate center-mounted avionics stack....
It is neither cheap nor simple. I cannot imagine anyone doing it for something as simple as a DG.