Hi Rob,
I was just about to drag my sorry self to bed cause I'm tired from riveting in new rails on the 170 today. I've been working on the annual this week in between work shifts.
A quick note or two about my job.
We replaced the pilot seat left track last year due to the elongated holes. In doing so, my IA took notice of the sagging floor in the cabin. So after making a hole pattern template, and before riveting the rail in, we made a stiffener and riveted it below the floor along the rail (same rivets that hold the rail on).
The stiffener runs the entire length of the rail, same width as the rail flange and bent 90 degrees (i guess this would be called the web) about 3/4". This makes it a little more sporty to buck the rivets, but the increased strength in the floor is incredible. There is a bulkhead below the floor that won't allow the stiffener to be one piece, so it needs to be cut in two (like 15" ahead of the bulkhead and 20" behind).

With that, we planned to do the left rail on the right seat this year. McFarlane rails by the way (nice). Well I must have used the scrap aluminum we made the stiffener out of last year so we did the airport scrounge run today and came up empty. However, I had some left over T-channel given to me from my buddy, so we cut it to length and used it. It worked so well we drilled out the right rail under the left seat and stiffened that one up as well. I can't use the T-channel on the outside rails by the door due to the boarding step attachments. So after Thanks Giving I will get some more 040 sheet and bend one more stiffener and conquer that right right seat rail.
As it stands right now with only three rails beefed up, I could get in there and jump up and down and the floor wouldn't move.

So there you go. If the floor in the ol 170 is a little worse for wear (like mine), you could give this a try. It really wasn't bad. But my IA is a pretty smart guy. I learn a lot from him. By the way, I would go with rivets over the screws.

Looking forward to getting together and checkin out your new rails.
Good night.
Tom

Thanks for the tip Tom, I'll keep that in mind. I ordered 4 new rails, rivits, and templates yesterday. They should be going on by next weekend probably.

I believe one of the guys I know that replaced the seat tracks in their Cessna used the old seat track on the under side of the floor as stiffener.

My A&I just talked to Cessna. They (Cessna) is extending the deadline for the installation of the secondary seat stop for financial coverage on the pilot seat. (From the end of this year)

PSA: McFarlane seat rails are now $200/ea (front/C-180A)

My fault, I waited to long. I'm not required to do the seat rails "yet", but will over the next 6 mo for safety reasons. Anyone know where the best deal on them would be?

Thanks

dogpilot wrote:Now think out it folks, rivets are for shear, how is the stress on a seat rail, tension. Use screws, they exceed the strength of rivets manyfold.

Rivets work very well in tension, and are pre-loaded to yield or near yield as a result of proper installation. As for strength, they are typically as strong or stronger than the fastened material. Riveted joint failures on well-installed rivets generally fail from the underlying material yielding, so it hardly matters if you have 2x stronger steel screws installed.

As for rivets vs screws, rivets are faster and can't shake apart. I looked at my rails during the last annual and figured they have several years left in them, but there are some tight spots to get a finger with locks and nuts into versus using a small bucking bar when I will have to do it.

Well this is an old thread but I ended up using rivets. I did the entire rail removal and install my self (with my IA checking my work). And it wasn't too bad, just takes time and some bruised and scratched forearms.

robw56 wrote:Well this is an old thread but I ended up using rivets. I did the entire rail removal and install my self (with my IA checking my work). And it wasn't too bad, just takes time and some bruised and scratched forearms.

I did the same thing, '53 180 right side seat rails. The riveting went quick. Had some sweet round bruises on my forearms.

Newb question here, but how come you don't hear about seat rail accidents with Pipers, Beeches, Mooneys, etc?
-DP

denalipilot wrote:Newb question here, but how come you don't hear about seat rail accidents with Pipers, Beeches, Mooneys, etc?
-DP

My current plane is a Cessna (first out of 5 planes, the other 4 were Pipers: Cherokee, twin Comanche, and 2 short wing). The Pipers did not have seat travel like my Cessna which is like 12-14 ". This is partly for comfort, but mostly to exit and enter the plane because the door on a high wing Cessna is kind of behind you when you move the seat forward in the position where you can reach the controls. I suppose this allows easier access and egress for the rear seat passengers. The Piper seats would only travel about 6-7 " (a lot less actually on the short wings, like 4" in my Pacer). So my guess at the answer to your question is because the seats don't travel back nearly as far.

The Cherokee seat rails end up against the spar box, so even if the chair slides, it can't go back very far before it hits the wall.