Main Gear Box Assembly

53B · Post by **53B** » Sun Feb 12, 2006 9:06 pm

Hello All,

I am in the process of converting my 172 to conventional gear via the Fravel STC. I have realized that the STC does not specify any rivet sizes (diameters) or rivet locations for the forward bulkhead stiffener and doubler plates (0513006-23 and 0713495-15 / -16). Additionally, I will need the correct rivet diameters to attach the upper and lower angles to the inboard and outboard gear support blocks.

If anyone has pictures of a correctly assembled gear box that they could share I would greatly appreciate it.

Also, I need the correct length for the bolts that replace the Hi-Shear rivets in the outboard gear support blocks.

Thanks in advance for any information. I have finally gathered all of the parts to complete the project. Hope to have it done by the end of May.

Mark

johneeb · Post by **johneeb** » Sun Feb 12, 2006 9:49 pm

Mark,

Take a look at the pictures on this link. If they are not any help perhaps the author (Metal Master) might be able to help you. He is a contributer here and certainly has been where you are going.

http://www.tailwheel.com/forums/index.p ... m&album=45

Joe Moilanen · Post by **Joe Moilanen** » Mon Feb 13, 2006 7:13 am

My friend is doing the same conversion as we speak. Do you know of any more gearbox parts around?

Joe
4518C

53B · Post by **53B** » Mon Feb 13, 2006 1:21 pm

John,

Thanks for the link. I'll be sure to contact him.

Joe,

I was fortunate enough to find all of my parts new surplus.
I found most items at C.A. Aviation in Coral Springs, FL 954-227-0669.
Preferred Airparts 800-433-0814 and Duncan Aviation 800-228-1836 also had a few things.

Tail-wheel parts came from Air Repair Inc. 662-846-0228.

Cabin steps came from Johnny Williams 325-944-8558. (I'm getting a field approval or adding them as a minor deviation. My PAI at the FSDO can't decide what would be the most correct since the STC doesn't mention them at all.)

Outboard main gear supports from P-Ponk 360-629-4812.

These parts were much cheaper than retail but still expensive. I was willing to pay for new though. I hear there is a place in Canada called Burlington Airpark that has several derelict 170 fuselages. Don't know if they're for sale but that may be an option.

Has your friend fabricated his tail wheel brackets yet? I cannot figure out an easy way make the compound curve to fit the contour of the tail!

I'm busy making support stands and cleaning and painting parts right now. I hope to start the actual work in mid-April when it's a bit warmer in my hangar.

Hope this helps!

blueldr · Post by **blueldr** » Tue Feb 14, 2006 3:43 am

I believe "P Ponk" has most all the gear box parts, and at better prices too.

Metal Master · Post by **Metal Master** » Tue Feb 14, 2006 5:44 am

Mark

Johne e b posted my attachment to tailwheel.com of my pictures. (Metal Master)

I have a lot more pictures that are more specific and more details that I could disscuss with you about differences between some of the various parts. But I think that the people at P-Ponk could give you more details about their fittings and the hardware that is required to install them. There are some methods you could use to help locate the plates that I could talk to you about if you have specific questions just ask. It will depend to a certain extent on the parts that you have. Just PM me with info or questions if you like. I am a professional aircraft mechanic and am out a lot of the time but generally look at the IC170A sight in the morning. I just got back from Bible Study this evening and took a look to see what was up. I am not asking for anything I am interested to see how this works out for you.

Regards,

Jim

N170CT · Post by **N170CT** » Tue Feb 14, 2006 10:01 pm

FWIW....I seem to recall that AC43-13B can provide the formula for determining proper rivet sizes. I know I have it in some of my A&P books, but they ain't handy right now. It is a function of the total material thickness one is rivetting. good luck, chuck

mod cessna · Post by **mod cessna** » Thu Feb 16, 2006 10:31 am

Great info guys. I as well am in the process of doing the conversion on my wan-a-B 170.
53B this is the first i have heard of the Fravel STC. Could you post a contact or e-mail me some info of the stc holder? All i want is paperwork. I have tried the Williams in Udal( i belive the old bolen stc) but have had no success. There is a guy, in Fairbanks, AK working on an STC, but the approval date on that is unknown, at this time.
Thanks for the help.

53B · Post by **53B** » Thu Feb 16, 2006 10:45 am

mod cessna wrote:Great info guys. I as well am in the process of doing the conversion on my wan-a-B 170.
53B this is the first i have heard of the Fravel STC. Could you post a contact or e-mail me some info of the stc holder? All i want is paperwork. I have tried the Williams in Udal( i belive the old bolen stc) but have had no success. There guy in Fairbanks, AK working on an STC but the approval date on that is unknown at this time.
Thanks for the help.

Here you go!
Ron Fravel
6060 Hwy 337 S.E.
Laconia, IN 47135
812-737-2867
ronfravel@aol.com