NMPRA

The all new EF-1GR-7 Kit designed by Dan Kane and Jery Small Is a performance pylon racer.
laser Cut from hand picked balsa and light ply, Build up wing with landing gear, plastic cowling, canopy and wheel pants.
elbertinnovations.com
Email or call for questions.
406-459-4855 elbertinnovations@outlook.com
More Pic coming soon

The all new GR-7 EF-1 Racer

I saw those close-up at the race at OJA last weekend. They are beautiful.

Tim

OMG yes, that's nice!!

The New web sight is up and running you can order GR-7, Little Toni, Tom Cat, and the Denight Special.
https://elbertinnovations.com/

Just some GR-7 picture updates

I hope this is a good place to pile on some GR-7 build questions and pictures.

I used 2 pieces of 3/16" zinc plated steel rod from the hardware store resting on some flat steel boxes at either end for a wing fixture. They fit the holes in the wing ribs nicely. I stacked the ribs onto the tubes that were numbered W1-W7 in order. There were several more smaller ribs that were not numbered and they went on by size until I got to the smallest wing tip rib. The ribs are very fragile. The tails are connected with a 1mm piece of wood and break off if you are clumbsy like me. I think I broke a couple ribs on each wing and had to reglue them after getting the rest of the structure built.



Before I start sheeting these wing panels, I want to figure out how to connect the 2 halves together. It looks like a tube can be glued into the 9/16" diameter holes that are near the center of the ribs. Is that the typical spar construction? That's not really shown on the plans.

The forward hole is for a paper rocket tube, aprox .540" OD with a .510" ID. I use 1/2" carbon or 6061 T6 alum for the joiner. The rear hole is for a rolled paper sleeve used as a guide for the aileron servo wires.

Hope this helps.

DK

Thanks for the info Dan, that helped me source the right parts for the job. I still haven't decided if I want to make the wing 1 piece or 2. But that seems like a pretty easy conversion at the end if I want to fuse it all together with the 1/2" joiner inside at a later time.

More questions.

1. Is the leading edge made from the convergence of the balsa sheeting that covers the ribs? The ribs seem "pointy" and not really designed for a hardwood leading edge piece....

2. Before sheeting, Should I remove the tails of the ribs in the aileron area and glue 3/16" Balsa in there to hold the hinges? I'm struggling to figure out the order of operations for making the aileron surfaces out of the ribs and sheeting.

Some photos to job memory if needed.
Ribs and plywood mounting hard points.


Sheeting all taped up and ready to glue down. Waiting to sort out anything needed inside before covering the skeleton.

kane wrote: ↑Mon Dec 27, 2021 11:04 am The forward hole is for a paper rocket tube, aprox .540" OD with a .510" ID. I use 1/2" carbon or 6061 T6 alum for the joiner. The rear hole is for a rolled paper sleeve used as a guide for the aileron servo wires.

Hope this helps.

DK

And one more question...
What is this white plastic part?

Regarding the LE...

This appears to be kit from Shane, I believe it to be the same as I originally designed it but I will try to help best I can. The sheeting is cut flush with the front face of each rib and a single piece of 3/16" X 1/2" balsa is applied to the face of each rib and then shaped to match an airfoil shape.

Aileron hinge support...I sheet one side, either top or bottom but not both at once. Once dry turn the wing over and trim the ribs along where the 3/16" hinge support would be, taper the wood and glue in place. Shape prior to installing the remaining sheeting. Here is a link to a similar build that may help make sense of this area...

https://www.rcgroups.com/forums/showthr ... ylon-Racer

Lastly, the white part is wing fillets. They are cut in half to reveal a left and right fuselage to wing fillet. they are glued to the fuselage. Most do not use this part but some do.

DK

Dan,

Is the wing on this GR-7 EF-1 strong enough to withstand the weight of a 5 or 6 cell battery in a turn at #1 Pylon.....

JSC wrote: ↑Mon Jan 24, 2022 6:09 pm Dan,

Is the wing on this GR-7 EF-1 strong enough to withstand the weight of a 5 or 6 cell battery in a turn at #1 Pylon.....

Hard to say... My guess is not without some glass. One could get creative and cut some foam cores and make it strong enough for sure.

DK

I glassed the center section of the wing as per the drawings, (Two layers of 4oz if I recall) I then glassed the entire wing with 3/4 oz cloth. As per the EF-1 rules I then Monkoted over the glassed wing.
My wing is two piece as it will pack better into a box for shipping. The other advantage of a two piece wing is if there is a roll to be trimmed out you can twist the wing.
I was still underweight when done. Pretty much any scratch/kit built EF-1 will be under weight and the ARF will be a little over.
If your 5 or 6 cell weighs the same as a 4 cell you will be fine. If its more then how are you going to balance the airplane and how will it fit?
Its all pretty tight up there.

Is this kit still available?