The first time I have seen a picture of the voodoo express designed by Nat Penton, it was almost like an illumination. Indeed, I was trying to find by myself a new design for a pattern plane governed only by the performances (not by the look). Then, I realized that Nat has already imagined this plane many years ago. Moreover, I think that this design is perfect for an electric pattern plane since it can be easily builded very light. Therefore, after the end of the construction of a more classical pattern plane (the Graviton http://www.rcuniverse.com/forum/m_90...tm.htm#9040604), I decided to start the construction of a second 2m pattern plane strongly inspired by the design of Nat's Voodoo express: the anti-graviton.

Construction of the Wing

The rib are made of 6 mm depron. I'm using a technique derived from the "laser method". Pieces of depron are placed to form a comb. Afterward, the ribs are cut with a CNC hot wire. This method is very nice because (i) the ribs are cut very precisely and (ii) the remaining part will form a support for the assembly and for the sheeting.



The first rib and the one situated at the extremity of the sheath are reenforced with 100g/m2 glass fabric and epoxy.



After the cutting, the ribs and the longerons are glued with alyphatic glue.



The sheeting is made with 1.5mm balsa. On the next picture, the sheets of balsa are sanded to obtain straight borders, assembled with tape and glued with alyphatic glue.



Stab construction

The stab and the rudder are made with foam sheeted with 1.5mm balsa. The two servos for the stab are placed inside the stab.











Rudder construction



If you are interested by this construction, I will continue to post some pictures and some explanations.

Good luck with your new project!

All construction design and construction threads are welcome for most of us, it's nice to see a pattern plane built from the ground up. Very interesting the depron ribs, do you have a weight savings in comparison to balsa? or it's just easier to cut them with CNC?

regards

Thanks

I do not realy save a lot of weight by choosing 6mm Depron rib instead of balsa. It will be possible to save weight with 3mm depron. However, Depron is very easy to cut and very cheap if we compare with balsa. In addition, I don't know if it's the same all over the world but in Belgium, it becomes very difficult to buy good quality Balsa. Then, when it's possible, I replace the balsa by alternative solutions.

Keep posting...
I'm really saving weigth by making the ribs as a sandwich on Rohacell foam and two carbon fiber layers... comes 1/3 of the weigth of balsa.

Then, I continue to post some pictures

The stab, the rudder and the small vertical wings are finished!



The longerons of the wing are reinforced with carbon, epoxy and a thin hard wood.



The trailing edges are also reinforced



Now it's time to start the construction of the fuse!

The motor, the controller and the Lipos come from china. I know that the small turnigy motors are very good if consider the price. I will test this big one.





The fuse will be constructed from 6mm depron formers.

The fuse sides are made with 4mm balsa partially covered by 160g/m2 carbon fabric + epoxy. A glass plate is waxed and coated vith PVA. The two pieces of carbon fabric are imbibed with epoxy and are placed on the plate. Then, the balsa is compressed on the fabric during the epoxy curing.











The holes are made with my new CNC mill.





The work on the wings is also going on.

The construction of the fuse evolves slowly



Any remarks about this construction?

Looks awesome! Keep up the good work. I might be making a smaller version that accepts a single 5 cell 5000 lipo. I scratch built a plane similar to this last year and it is very rewarding in the end. Although it takes forever the end result will be very worth it!

-Chris

Very interesting, and good work. One thing I have noticed is that when making flat panels, as you are doing here, the PVA is not always needed if you are laying up an a really smooth surface. I have not tried glass, but have done this with 3mil mylar sheet stretched over a smooth surface, and it does not even need waxing. The mylar sheet peels right off.

Thanks

Yes it's not necessary to use PVA in addition to the wax. It was just a security because I'm scared to have my stuff stuck on the mold. To have a perfect surface quality, it's even better to avoid the PVA.

More pictures soon...

The work is going on slowly.









Still a lot of work...

Geoffrroy, very nice thread, keep posting. I like your foam cutter, is it hand built?

Bundu

Thanks. I need some motivation to finish the work now...

Yes the foam cutter is a selfmade one. Here are some pictures:

Very nice indeed, need motivation?, look at the pics of that plane and get on with it and finish it .......post a pic when it is "alles klaar".

Cheers
Bundu

I'm approaching slowly the end of the construction. But still a lot of work to do...

We are close to the first fly!



I can post more pictures if you are interested

After a crash due to a radio problem (probably induced by the carbon inside the fuse...), I replaced the turnigy motor and controller by an AXI 5325/18, a Jeti SPIN 99 opto controller and an APC E 19 x 12. I keep the lipo turnigy 20C 8S 5000 mAh. I have really more power and the weight of the plane is now only 4.6 kg ready to fly.

I'm really happy. The flying characteristics are awesome.





Someone have some news about Nat Penton?

Thanks to www.insightrc.com for the informations about the voodoo express.

Geoff,

Congratulations. Very nice construction work!


Best Regards,
Mark

Nice job, Do we have any video to share?
Cheers
Guille

Geoff,
You asked about Nat Penton.
I live in the same city as Nat and consider him my mentor.
He is Not flying currently.
His wife passed away last year after a rather lengthy illness and it took quite a toll on him both mentally and physically. He just hasn't gotten encouraged to get back to flying since then. I keep hoping he will.
I enjoy every visit with him. He did come out to a couple of pattern meets this year here in D-6(USA) to visit and everyone enjoyed seeing him.
I'll tell him you asked about him.

Eddie

Thanks Mark. I'm happy to obtain some congratulations from you.

Guille, I'm not a video specialist. But if I have the opportunity to make a good video, I will share it here.

Eddie, if you have the chance to see Nat, do not hesitate to tell him that a guy in Belgium has build a F3A plane strongly inspired by the Voodoo and that I'm very happy about this plane.

Already have as I knew he'd get a kick out of it.
He enjoyed looking at your construction photos.
I'll have to give him an update to let him know you've flown it and are happy.
I've enjoyed your thread also.
Eddie