Riveting

[tasmithind]

Does anyone know if there is a special procedure that needs to be done to use CherryMAx rivets in place of bucked rivets for building wings? Does any prior approval need to be done wth the FAA?

[raytoews]

On a homebuilt airplane I don't think the govt gets involved. It is between you and the gods.

[martymayes]

On a homebuilt you are own your own so do your homework. Pulled rivets are not a direct substitute for solid rivets, might need to adjust rivet pitch or otherwise redesign a joint due to fastener substitution.

[Qmiester]

Beg to differ with you, but the only pull type rivet that the FAA bans in structural work is the old pop rivet. The Cherry Max rivet can be used as a straight substitute for a solid rivet provided it is not used in certain areas (ie. landing gear attach fittings, control mounts, wing and empennage attach fittings etc). If you want to read it for your self, go to http://faa.gov/ then type in AC43.13-1B on the search block, when that comes up, go to Chapter 4, then to section 4 and then to Para 4-53. You should find out more about riveting there than you really wanted to know.

[martymayes]

I'm familiar with it.

There are certain locations were pulled rivets are not permitted under any circumstances- - in fluid-tight areas; on aircraft in air intake areas where rivet parts may be ingested by the engine, on aircraft control surfaces, hinges, hinge brackets, flight control actuating systems, wing attachment fittings, landing gear fittings, on floats or amphibian hulls below the water level, or other heavily-stressed locations on the aircraft.

and in your reference there is the old standby catch all:

CAUTION: For metal repairs to the airframe, the use of blind rivets must be specifically authorized by the airframe manufacturer or approved by a representative of the FAA.

Of course, with a homebuilt one can do as they wish but I would think twice before substituting pulled rivets, regardless of brand name, for solid rivets, especially in a structural application like a wing, which is what the OP was asking about.

[Matt Gonitzke]

I would not use blind rivets on a wing spar or any other highly-stressed structural member unless the aircraft was designed that way. The fatigue quality of a joint riveted with blind rivets is inferior to one riveted with solid rivets.

[Bill Berson]

Does anyone know if there is a special procedure that needs to be done to use CherryMAx rivets in place of bucked rivets for building wings? Does any prior approval need to be done wth the FAA?
Spar flange or skin?

[tasmithind]

The original design was a glued wing, I have plans for an all metal wing and want to use a 3214 CherryMAx rivet to attach all the skins. The fuselage is already designed to be built using such rivets so I am trying to see if using them to attach wing skins is acceptable as well. I will look up the FAA circular as advised in the posts.

Here is why I am confused. This technical data was pulled from the FAA circular AC43.13-1B and CherryMAx technical data sheets. It clearly shows the CherryMAx is much stronger.

AN427 100 Counter-SunkHead MS20427 ShearStrength psi 10000



CR3214

5056 ALUM. ALLOYQQ-A-430

8740 ALLOY STEELAMS 6322

A-286 CRES AMS 5731

CHEM FILMMIL-DTL-5541PLAIN COLOR

CAD PLATEQQ-P-416TYPE II CL. 2







Shear strength

50,000 PSI

[tasmithind]

Skins

[Bill Berson]

I don't know what you are building, but I would consider Avex rivets. They set nice and are about 10 times cheaper.
The shear strentth is less. But how much shear do you need?

[tasmithind]

I don't know what you are building, but I would consider Avex rivets. They set nice and are about 10 times cheaper.
The shear strentth is less. But how much shear do you need?


Bill
I am building a BD4. Thanks for the tip I will look into Avex rivets too.