Fox 1:3 from Tomahawk Aviation - FES version assembly thread

[Steve P]

Preview of coming attractions! Tomahawk Aviation acquired the former Rosenthal Flugmodelle 1:3-scale Fox fuselage mold and created a mold for the wing with an updated airfoil.

Fox #1 has arrived at the home of its adopting family in America. Fully optioned, receiver ready, FES version, Revoc wing/tail/fuselage set. Thanks to Bruce at Rosenthal USA/Tomahawk USA for making all the connections.

This will be a fairly concise build thread mostly to document the model.

Scale 1:3
Span: 4.66 meters
Length: 4.26 meters
Weight: ~11.5 kg
Construction: Fiberglass and carbon
Motor: Hacker A50-12L glider KV355
Controller: Castle Creations Edge 100A
FES: Torcman FES EX-UNI 8 system
Power: 6S 6200 mAh 100C
Electronics: PowerBox Pioneer, 2x 26D receivers, 2x PowerPak Pro

[Steve P]

With temps in the nineties this weekend, the workshop will be my refuge and the Fox my project.

I didn’t want to be completely rudderless this evening so I got the fuselage back on the bench and installed the rudder.

And a nice rudder it is. Lightweight!


Ball joint linkages to the pull-pull cables


Center post has a ball bearing and washers for clearance. Receptacle is brass.


Foxy!


Rudder and elevator MG HV servos

[Steve P]

After a morning of yard work, cool down mode was some fun with dolls and arts & crafts. Some legectomies and butt reductions were in order.

[Steve P]

Then on to the less fun stuff of trying to get as much weight as far up front as possible.

I realized my plan of a single 6S 6000 pack would require in to be in the middle of the cockpit area while two 3S 5500s would fit nicely to either side of the motor with the speed control tucked directly behind the motor. It all fits and the ESC can breathe.

[Steve P]

Located the Pioneer, receivers and all the related wiring. One receiver up high on the elevator/rudder tray to the right side of the plane, antennas pointing backward at opposing angles, the other forward on the left side of the fuselage one antenna vertical upward and one horizontal pointing ahead.

Still need to decide where the switch will be located?

[Soaranator]

Don't forget to give the passenger, usually the person in the front seat, a barf bag...

[Steve P]

Wurst und bier erbrechen bag

[Steve P]

I hate floppy canopies. On this model, they go all the way over and hit the side. One big gust of wind if they unlatched in the pits and they can snap right off. My solution here was a couple simple leashes using 0.032 Kevlar cord.

[Steve P]

Not much time today to invest in the workshop. Project number one was to get the RC system batteries mounted and then a quick project to hide the rudder and elevator servos from view.

[Steve P]

From the small things make a difference department…. The seat pans are flexible so that they can be removed from full length mounts running down each side. By flexing the front of one side it is possible to make them pop out. Unfortunately, with the weight of a 1/3 scale Axel pilot in place they also tend to flex and fall through, downward into the fuselage. My hopeful solution is to make one side —that does not need to flex to remove — slightly more rigid with the addition of a strip of pre-preg carbon sheet. The front pan also made slightly wider tapering from front to back.

Easy peasy….

[Steve P]

The seat pan mounts running down the sides of the fuselage are all structure made from laser cut ply. The next arts and crafts project was to paint out all that plain wood in gray so it blends with the seat pans. The boys got seat cushions, headrests, control sticks and tow releases.

[Steve P]

No. Seriously. That’s exactly the way Tomahawk details the elevator linkage. Gluing a lock nut to one side of the horn and then accessing the bolt through the opposite side. Really.

[Steve P]

Well that didn’t work at all. Nut cracked right out of the epoxy. Onward to JB Weld!

[Steve P]

JB Weld is a much better approach!

I also added two M3 nuts to the mix — one on each horn outside, the distant one then extending to the locknut. Plenty of threaded retention. This approach releases the ball joint but retains the screw so it doesn’t fall inside or some alternate universe never to be found.

I do think the elevator setup in general is a PITA. Especially outside at a flying field. Two thin wing servos in the horizontal would be a vast improvement. I did that on the Valenta Fox and it worked perfectly. Even better with today’s LDS. That setup in my Antares is rock solid.

[Steve P]

Initial program finished while seeking to keep it simple with three flight mode presets — camber mode drooping the entire TE slightly which I also hope will work on tow, cruise mode with a bit of aileron to rudder mix, and aerobatic mode mixing flaps to ailerons and no rudder mix — and best of all everything is moving in the right directions. Throws will have to be refined.

Without airbrakes, crow is the landing recommendation. I think it will take a few flights and knocking knees on approach to get the proper combination of flap-aileron-elevator comp dialed in. I right now have a good bit more flap than Tomahawk specs, but that is what moving the left stick is for.

Balanced just a skinny hair nose heavy @ 110mm with 1.5 ounce of lead in the tail cone. I guess I could scooch the receiver batteries back an inch, but with a big beast like this, what’s an ounce or two?!

Now need an opportunity to get it airborne and refine things! I’d prefer to start with a tow versus try to ROG a brand new plane and untested setup.

[Scalesoaring]

I like how you snuck in the "Dummies" book...

The elevator connection solution was a good idea, but I agree dual servo would be best. I know Brian drilled a hole of the other side so a nutdriver could fit through.

Bruce

[Steve P]

Some graphic intervention last night. I stuck with the dark gray and silver theme....

A little tribute to the home town of Tomahawk and its most famous former resident


Damn right it's a FES, take your purist attitude elsewhere


PowerBox inside


Adding to the wing


It's may look crooked here, but it is aligned with the main wing graphic.