This is a peek at the electric Viper I am working on. I am shooting for 53-55 oz RTF. So far I am on track. There are some neat features I just can't show in pictures but here's what I have got finished.

Moments are 11.25 nose 17.5 tail. 702 SQ inches 11.25 root 8.5 tip. 2826-12 AXI and 5s TP 2700 MAH batteries. All old school construction methods and numbers. Just a few mods to bring it to electric.

Looking great.  I see he is sold on I-Beamers.

Now the fun begins. This is the third airplane I have built this season and I have a fourth started which would be done if I didn't have to rebuild this one 4 times. On this airplane I attempting to make it mid 50Ty's. So I went to the 2826-12 AXI motor so I could use the 5 S 10 ounce battery. I have made 4 beams 2 fuse 4 turtle decks 2 stab and elevators. I had bought Kaz landing gear for 5668 yen and they are neat but too heavy for this plane. I took a old Windy landing gear and sanded them down to 1.75 including wheels. The sanding on the inside of this plane (that will never be seen) is as good as the outside. The ribs are stitched with Kevlar thread at mid point.


702 square inch. I am hoping this motor will pull this plane with authority. It should be fine if I can keep it light.

As it stands now with battery and wing tip weight its at 45.5 ready to fly less covering. Today while driving I thought of Momokote but I can bring myself to it. So I have 10 ounces to finish this in. Very doable. Its been a real battle to make it this light. The availability of good wood on my end is tough.

I made 4 spars and I think at 2.5 ounces even thought lighter than the rest it could have been lighter. the stab and elevators was 2.5 and I was happy with that. The batteries I have for test flight are the Zippy 5S 2700 at 11.5 so I can drop another ounce off the nose with the TP batteries.

All and all I am please as it should come close to target weight 55-57 ounces. Allot of work to drop 4 ounces.

Hi Bob,
So this would be the charmed Viper that narrowly avoided a squashing?

Dean

Looks nice, I like the fin shape. But I'm a little worried about the wing mainspar. It looks flexible. L

The main spar is white pine and it a unitized method of construction. Any one part would flex but it's the sum of the total parts that make a beam wing work.

Sure

Strength and stiffness are two different things. The sum of all the parts might make it strong enough, but is it rigid enough to maintain proper aerodynamic shape?

I can see that Sparky hasn't given up on flying a zero weight plane yet!

I see more and more following that path. They say it don't matter in one breath and in the next ask how much does it weigh. It is plenty rigid enough unless its 70 ounces.