Boot cowl rivets and wing roots

Hi everyone. My boot cowl is fitted and clecoed in place. I'm ready to rivet. I'm trying to decide if the relatively thin material should be dimpled/countersunk for flush rivets, or if I should take the more obvious route and use domed rivets. Is there a norm here?

I'm considering putting my headset jacks and an intercom in the left wing root. Since this is my first cub, I'm not really sure how much depth I have there, and if a 4" deep intercom box mounted to the cover will fit.

Thanks as always,

Adam

Domed rivets are the norm, however you could use flush rivets. If your material is .025" then you need to dimple. If its .032" then countersink it. the wing root area is probably not a good place for any electronics as it will get wet.

john

Domed rivets. Flush rivets won't give you any more speed in a Cub and you'll have to dimple all layers, not just the top skin. Countersinking always makes a weaker joint. So does dimpling without the right tools and technique. No electrical pwr anywhere near fuel tanks, audio jacks are OK in wing roots if mounted on a raised (1/4") bracket (Make sure you insulate the jack grounds from the airframe... http://www.aircraftspruce.ca/catalog/avpages/plugs_paneljacks3.php). My 2c.

my vote domed... they are all hid out of airstream behind cowl doors...

Of course just my opinion, but I flew a friend's cub to Osh last week, His plane has the jacks in the wing root, they were a pain compared to mine in the panel. My Zulu headset battery box control unit kept bouncing around and banging me, and I didn't like the weight of the batteries hanging on the jacks. I much prefer my jacks in the panel, where the control box can sit nice and quiet up on the 'dash' nestled against the windshield.

doug.

My recommendation is flush. Domed rivets are a pain to sand around and paint around. Just bump one pass over the top with sandpaper and you will be looking at bare Aluminum. Also easier to get runs around domed rivet heads. Just a lot easier to finish/paint over flush.

I prefer jacks in the throttle cover. Up in the wing root and they will get in the way of photographs, elbows, tangled up in the shoulder harnesses and just about everything else.

Bill

Domed rivets or nutplates and screws.
I've always put the intercom in the instrument panel. The jacks work very well in the wing root. If the throttle quadrant is made for it, they work well in there too. By being made for it, I mean make the lower lip deep enough to mount the jacks facing straight down.

I've never figured out why people put the jacks in the wing roots. The lower down the better, I have them pointing down out of the armrest in another plane and it works really well. Don

A lot of folks like them that way Don. They prefer the cords hanging to the side rather than from the instrument panel. They also don't like the cord around any of the controls.(like the flap handle)

Aerodon said:

I've never figured out why people put the jacks in the wing roots...

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All the transport category airplanes I flew had the audio jacks somewhere over and behind my ear. Must be a reason.

I screwed my boot cowl together, but flush rivited all the nut plates and such...

Aerodon said:

I've never figured out why people put the jacks in the wing roots..... Don

Click to expand...

thats usually where I put them, and now that all my interiors are Kydex, I heat form nice bump-ins for the jacks.. above a vertical tube for cable to run down...

I like the jacks in the wing root. Velcro your headset power supply to the tubing. Like someone said, less prone for cords in the flap handle, seat belts etc. Flew a Cub a lot with them in the throttle panel and the cords got in my way.

I have used screws and nut plates so that the boot cowl is removable and also done it with flush rivets. The brazier head rivets protrude up and eventually, even thru the anti-chafe seal, wear into your engine cowl. Doesn't take that long to dimple with a hand squeezer.

For a project like the boot cowl, it is well worth while to look around for a reasonably good, rebuildable pneumatic rivet squeezer. I bought the one in my shop for $300 then disassembled it (careful, needle bearings will fall out), sanded & reblued it, put in a new seal kit then mounted it on an old engine stand. The foot pedal is one sold on line for Go Karts.
http://www.bmikarts.com/Pedals-Footpegs_c_244.html
The pedal is actuated by an Aircraft Spruce sourced reasonably priced push-pull cable. Not difficult to put together and a real aid in sheet metal work for both dimpling and riveting. Once it is set up with the proper spacers for the job at hand, it will perfectly rivet the next thousand rivets. Be sure to get one with a 9 1/8 inch throat. Parts are available and new ones too but they are over $2000. I have about $400 total in this one. I see them on eBay occasionally. Don't accidentally squeeze your finger as a friend of mine did!
http://www.ebay.com/sch/i.html?_trk...w=pneumatic+rivet+squeezer&_sacat=0&_from=R40

pitts12driver said:

Hi everyone. My boot cowl is fitted and clecoed in place. I'm ready to rivet. I'm trying to decide if the relatively thin material should be dimpled/countersunk for flush rivets, or if I should take the more obvious route and use domed rivets. Is there a norm here?

I'm considering putting my headset jacks and an intercom in the left wing root. Since this is my first cub, I'm not really sure how much depth I have there, and if a 4" deep intercom box mounted to the cover will fit.

Thanks as always,

Adam

Click to expand...

Years ago in doing a boot cowl for a certified Cub I chose to use countersunk rivets to replicate the smooth spot welds where the stiffening angles are spot welded along the sides, top and bottom on an original Piper boot cowl. Because I wasn't replicating Piper's plumbers seam for the joins, I butt joined it at those locations with a splice plate, because I didn't want a lap joint. Because I'd started down the countersunk rivet route, I dimpled or countersunk those rivets too. The only domed head rivets I used were the 5/32 ones to hold the internal cowl channel angles and of course the ones around the firewall where the crimped flange is riveted to the firewall. I know there are other ways of building a boot cowl, but this one was following the Piper design as closely as possible.

I flew that plane for 12 years before selling it and each time I looked at the boot cowl I liked the way it looked.

Use whichever rivet style that is going to give you the most pleasure when you pull open the hangar doors.

Post some pics as you get started!
Andrew.

I saw these 'click-bond' nutplates at Oshkosh. I like the idea of only drilling one hole and epoxying the nutplate into place. leave the 'puller' in place until its dry, or svn until its painted. Many different styles available, including hangers to hold wires that pass through wing ribs. Neat.

Don