Not much dimpling?

The videos seem to show button head solid rivets on the fuselage. The VS and rudder seemed to be flush riveted, but the HS and elevators were either button head or pulled rivets? I never got a good enough view of the wing to see what was happening there. Hard to tell. Also, what is the point of that strip along the trailing edge of the elevators perpendicular to the airstream?

If I time it right, my -8 will just have moved out of the garage when the -15 kits ship. The compressor may still be warm.

Does it really matter? You know good and well you are going to swap every buttonhead for a flush wherever you can.

Remember this is an engineering prototype, and certain things, like rivet type, will have been done for expedience. The final kit may be different in many respects, including the types of rivets.

The wings on the prototype had both solid and pull rivets.





The recent webinar indicated that the Gurney flaps on the trailing edge of the stabilator will be gone in production.

No doubt there are many changes still to come. Still, if they're trying to get a feel for performance, and going to the extent of putting in what is likely to be the final "standard" engine, then it would be interesting to see what difference there is should they go "flush" later.

I expect there is a crossover airspeed above which flush matters more than build complexity. Even the tail area of many airliners have button head rivets because by the time the air gets there, it's already so turbulent it doesn't matter.

If the lessons learned in the -10 and -14 about easier build-ability, with full size holes, etc. are applied to the -15 with apparently far less dimpling, this thing is going to build FAST!

So it's a conundrum ...

STOL guys want drag, which means pull rivets are going to be preferred ... and they'll have 26+ inch tires which means a speed penalty that they don't care too much about.

So the fastest 15 would likely be with flush rivets and small wheels/tires.

Really, if speed is your thing, there are better choices.

I'm looking forward to doing an apex STOL build

It's an interesting conundrum for sure. Wheels and tires can be swapped out. Rivets can't. While at certain times STOL guys would seem to want drag, I'd guess they really want only as much drag as they need, and then on take-off they want it all gone. I flew the F-111, so I understand wanting one plane to do many things well. In the end it really didn't. It did one thing superbly. If you're putting in a 230hp engine to achieve a top speed of 140kts, it seems to me you're expecting to be dragging around a lot of ... drag.

Isn't the target for the -15 the Cessna 170? Buttonheads everywhere you look.

Lower drag at a low cost is always a good value even for backcountry aircraft. It may have little to do with speed rather efficiency.

Go north 100nm past the USA-Canadian boarder. The distance that my craft take me into the bush and then get me back to safety depends on efficiency. And when that distance expands the mission area grows exponentially. Think fuel flow at Carson speed. Studies may show that some dimpled rivets might help.