Thorp Air Command - T18.net

Looked at a T-18 the other day and on the
center wing section the main spar rivets were
smoking really bad on the bottom of the wing
and a little on top.
What's going on here?
Dave

When I was shopping for a T-18, I did see one with smoking rivets on the bottom of the center section and out under the wings. It had the old original rivet call -out.
If you use this forum's search function and use the words spar rivets or other similar terms, you can get a lot of info that might help.
I was looking for a T-18 that could quickly be brought up to flight worthy condition, as I'm building an RV-8. Drilling out a bunch of smoking main spar rivets and laying out supplemental rows of rivets, drilling, countersinking and riveting in new was more than I felt up to doing.
Thierry, our Canadian contributor seems to enjoy this, and shares his craftsmanship regularly with the forum. Perhaps he can shed some light on it. But mostly, I think you should want to do it, and look forward to the challenge, or let it go.

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE

This topic appears from time to time and there is a LOT of info as suggested if you search the Forum .

RB

I did use the checklist provided here and the leading edge
ribs only have twelve rivets on the top.
Was the additional row of spar rivets a mod that was incorporated
At the same time.
How do I get a hold of the newsletters?
I don't have a set of plans, is that something I should purchase
prior to buying? I would think most airframes would include the
Plans they were built from.
Is there a plans serial number list that shows the block point changes?
Thanks,
Dave

When anyone buys a set of plans the are authorized to build one airplane. There is no valid reason to keep the plans when the builder sells the plane. If the seller does not have the set of plans to go with the airplane, I would walk away. I have built three homebuilts and have never bought one. I suggest you hire a VERY experienced T-18 builder to inspect any proposed purchase prior to buying.
Steve Hawley

Steve,
I have some experience maintaining and repairing
aircraft.
I also have enough experience to ask when I don't
know something, and there appears to be a lot of
really experienced Thorp builders/owners here.
I appreciate everyone's time, just trying
To get a little smarter.
Dave

The center wing section gets a lot of "stress/flex" from folks walking on it to get into the AC possibly causing the "smoking gun"...IMHO . To help beef up the center section it was recommended to add an additional rivet between the current nose rib rivets . I also did it on the outer wing nose ribs (easy to due in the building stage) . The other additional fix was to add a second row of rivets to the main spar on the center section (also easy to due in the building stage) . It is also possible the original rivets were not set properly causing them to "work loose" . If you don't want to add the additional rivets you can drill out the "smoking rivets" and replace them with Cherry Max rivets . I am not an Engineer so my opinion is just that...toot, toot !

RB

Hi.

For my it's a no go. If you push with your finger on the skin around the rivet head and the skin was loose it's not good. Cherry max is a fast solution, Just a band aid for a period of time. And after all removing flush cherry max is a lot of work. My 2 cents: removing the outer section wings, inspect the inside centre section via the aileron bell rank hole and after that made some work decision.
For me this a real problem. Thorp expert or not aluminium structural skin design is the same for all the small plane, but for this kind of aircraft 160mph average speed you have to take the time to repair that.

_________________
Thierry
French Canadian T-18
C-FPVE #091

Thierry,
Thanks, I was coming to that conclusion also.
I'll keep looking.
Dave

The standard Thorpaircommand.com party line: "They all smoke."

This is my center section. Some rivet was smoke after 230hrs flight time. Dosen't mather I have to rebuilt this section entirely.



Maybe when I rebuilt the center section I put standard rivet (not flush) on the spar. I think this way eliminate the problem. I have to study this avenue!

_________________
Thierry
French Canadian T-18
C-FPVE #091