Panther Sport Aircraft Forums

Matt, I think you will be happy with your choice to build with protruding rivets. The speed penalty is minimal. The only distractor would be application of vinyl graphics. There are a few locations where you may wish to consider dimpling. I used flush rivets anywhere I anticipated a fiberglass fairing laying tight against the skins, such as the canopy fairing and the tail fairing.

Well all I decided on protruding rivets. I just now finished my tail kit minus a hinge I accidentally cut and am waiting on replacement. Total time I have in tail kit is 39.25 hrs

Just as a data point, I've completed the tail, fuel tanks, both wings, ailerons and flaps with flush rivets. I keep fairly close track of my build time and dimpling has takes 22 hrs so far working myself without a helper. So far, not a real big impact. There's undoubtedly some additional inefficiency introduced by having to hold off some parts of the assembly until after dimpling those areas but I don't think that amounts to much.

Just wanted to say thank you to all that have responded. I think I've decided protruding after reading into the bm and suggestions here. Seems I could save alot of time just by not having to dimple. Plus I think the protruding looks just as good ten feet away. I also thought of just doing flying surfaces flush. But think it might look odd the fuselage being all protruding and flying surfaces being flush.

I went with all flush except for the fuselage bottom, but I have an airplane to fly currently and am not in a hurry as many are (think I like building more than flying actually). Have had minimal problems with a consistent look of the rivets or proud stems. And the idea of wrapping vs. painting would go better with flush.

But as Bob Woolley (who has build several RVs and a couple Panthers) said, 'I will never dimple another rivet hole', his Panthers are all protruding and as someone else said they look fantastic.

Rick H

I have been going with flush rivets, I may use protruding on the fuse cage when I get to it but still not sure. If you do decide to go flush you should read the article on using the DIENQ dimple dies. I have been using the DIENQ with very good results so far.

https://flywithspa.com/dimpling-for-flu ... te-solved/

S/N 083 here. Built by 3 guys in 8 months, using protruding head rivets. We chose the universal heads over flush heads for speedier construction, not a speedier plane. And yet, I find the plane to be plenty speedy and sporty the way it is, with only an O-235 Lyc.

Yes, we had to purchase additional rivets separately, but Aircraft Spruce stocks and sells them, and it's not that much extra cost considering the time saved; or compared to the cost of some of the other items you'll need. Plus, if you're doing flush rivets, you will need to purchase or borrow a C-Frame dimpling tool to reach the holes out in the middle of a sheet. In my experience, that is often a two person job, one person to manage and hold the larger sheets, the other to whack the dimple die tool. I have a lot of experience with solid-shank, flush rivets on an old-school RV kit. They DO look very nice, if that's what you're after. But dimpling and countersinking simply add more time. How much extra time depends on the experience and efficiency of the builder. I learned from our team build, that different builders approach different aspects of a given task with different viewpoints and techniques. So it's hard to say exactly how much time is added by going with flush heads.

In my opinion (and take it for what you paid for it ), . . . dimpling and machine countersinking everything, including the outer skins and all the underlying sub-structures (ribs, spars, bulkheads, steel cage, etc.) could add as much as 100 hours to the overall build of the Panther. That's a SWAG, but I know what it takes to build an RV wing, and the Panther wing was an absolute dream to assemble using protruding-head pulled rivets. The three of us assembled each wing in about 1 week per wing (after we assembled the main spars, less paint & wingtips).

It really comes down to YOUR mission for YOUR airplane, and how much TIME (& money) YOU want to invest in it. The mission for OUR Panther was to complete it as quickly and as safely as we could, so that we would have something really fun and sporty to fly and enjoy and be proud of. We were not aiming for a super speedy racing version of the Panther, nor a stunning showplane or eye-catching award-winner, nor a champion aerobatic mount, nor a day/night IFR X-country machine. Even with our simple approach to the project, the Panther has exceeded our expectations, both in terms of build and flight handling.

Best of Luck on your project!
Les

I am builder SN020. I had never built a metal aircraft, however have built metal fuel tanks and have many friends at the airport who have built RV, using both solid rivets and pulled rivets (RV12). I agonized over the choice, having no experience with pulled. My choice was more of a flip of the coin, but the ultimate decision to go flush was for the added strength.

Two things that would affect my decision if I were to ever to do it again. No dimpling of the steel cage and thus what would be flush and what would be protruded. I had very bad experience with most of the flush rivets, with some types being better than others. Many of the types were very prone to "proud" mandrel stems. BSPS-42 being the worst.

So, for me it would be like this:

Protruded on all the steel cage and the matching line on the aft fuselage for visual continuity. Protruded on the entire underside and all flying surfaces, except for the leading edge. I would not go flush on any areas that required counter sinking and this does include that part of the leading edge that is attached to the main spar. Not that it is hard, it is just results are not reliably repeatable, and I think that has to do with heat building up in the surface and the countersinking tool.

Bottom line, if you choose to dimple, get yourself a super dimpler or borrow one. Going protruded on the entire plane will make it more simple. I think the first one I saw with all protruded was Bob Wooley's, and it looked great.

I now have all the flying surfaces and tail cone complete using flush rivets. If I were starting over, would probably use protruding head rivets to reduce build time and eliminate counter sinking. Dimpling skins and ribs is no problem, but for me, counter sink drilling is a pain. Also, where you have two overlapping skins over a counter sink ( such as wing spars and tail cone upper longerons) it is difficult to get the skins to lay perfectly flat. Mine is acceptable but not as smooth as I would like. This would be a non issue with use of protruding head rivets. Like building a house, there will be things you might do differently and perfection is to be sought but not quite achieved. I am pleased overall with the results.
Myron
098
098

Matt,

If you search this forum and others such as Van's you will find a lot of discussion on this topic. On my build I went with flush rivets because I like the finished look and I may do a vinyl wrap when I am finished, so it will lay down better without protruding rivets.

Other advantages are that flush rivets are included with the kit, so less expensive. May be a stronger structure, but there are many opinions on this subject, and it really is not any thing I would consider as being important. This is a very strong aircraft either way you build it.

The most important subject is time! And I'm sure this is why you asked the question. My answer is yes it takes more time, but in the overall build time, I feel it is a mute point. You have to disassemble everything after the final up drill to de burr anyway, so dimple time is all that is added. It may add an hour to each tail piece you build. The wings will obviously take more.

Just make a decision and enjoy the process either way. If speed is your biggest concern because you just want to fly, consider flying something else during the build process, it will be much more enjoyable to you.

Barry