Official Freewing 70mm F-35 V3 (2019 Version) Thread

[Barnacle Ben]

Thanks Robert!

[Robert Belluomini]

That is some incredible modeling you have done!

[Barnacle Ben]

Added ~2.25 inches to the tips of the stabilators and about 1.25 inches to the tops of the vertical stabilizers. AUW 2500 grams (89 oz) with HRB 3300 battery. Sweet spot for the CG i've found to be about 25 mm aft of the factory recommendation.

Maiden flight was earlier this week, dangerously tail heavy (i'll never trust online CG calculator again). Able to land safely despite the wild pitch fluctuations, moved the battery forward about 2.5" which resulted in a slightly nose heavy condition but flew so much better. Tweeked the CG from there to get my optimal spot. Flaps cause a pitch down moment, so I mixed in some up elevator to the flap channel. The LG and doors work perfectly, I was worried the relative wind would flutter the doors in flight but they seem to be pretty solid. I was worried it wouldn't want to rotate with the mains aft from the factory position, but it rotates fine on pavement, haven't tried grass yet. The wider LG stance really helps with stability in landing, it's rock solid with no tendencies to tip over. Honestly it could be a jet trainer, it's very stable and slows down nicely, especially with the gear and flaps down. After I got the flap/elevator mixed in and the trim dialed in, you could honestly land it with throttle alone (you definitely have to land with some power in).

[Barnacle Ben]

Thanks Ausie!

Wings are epoxy'd on, not removeable. Built in ~5 degrees of washout at the tips. Used the grey acrylic paint offered by Freewing found in the F-35 parts list, but found it to be a tad darker than the factory paint on my model. Added a dollop of white to the mix to make it a closer match, and with that and some weathering it blends in nicely.

[f4u ausie]

Nice. That's alota work

[Barnacle Ben]

Landing gear fairings carved from balsa blocks, weigh in a 11 gram each (before glassing). Gear doors cut from the fairing and hinged outboard. Doors operated by main landing gear movement, no separate servo. The main gear closes on an actuator rod hinged at the fuselage and connects to a control horn on the gear door. This control horn was a p.i.a. I screwed up the geometry with the first attempt, so the doors would only close halfway and would bind up when opening. I finally figured out that I needed to make a curved, slotted control horn, similar to a fowler flap guide. The door opener is just small wire bent to shape that acts as a kind of torsion bar.

[Barnacle Ben]

Over the past few months i've completed a "Charlie" conversion, designing and building new wings and landing gear to convert the F-35 from the A version to the C, or "charlie" model. I never liked the looks of the stock landing gear with it's non-scale location, inboard and forward of the full size version. So I borrowed rotating retracts from the 64 mm F-14 and moved them outboard to the wing roots and aft a few cm. The functioning landing gear doors were the most difficult part of the project to get to work right. Balsa was used for the entire wing structure except for the aluminum spar guide and the LG mounts, which were made from bass. Used the front wheels from the F-14 also. Total weight gain over stock was 10 oz (about 3 oz were from the epoxy/fiberglass cloth finish). Total wing area increase is 130 sq inches.

[Andyb1029]

Morning all

Pretty new to this hobby (I will be practicing on basics before flying this)

I'm after buying this package from MotionRC and just after some guidance

Can anyone list me the must haves to improve the out of the box jet from MotionRC, improved electronics, added gyros for in flight and on the ground etc

I've seen afterburners referenced on here but nothing comes back when I do a Google search, can anyone point me in the right direction?

Is there anywhere I can buy the modified 3D printed parts already painted? Cheater grill, nozzle, any other bits worth changing out?

Please find a screenshot attached of what I was looking out. I'm very much looking forward to venturing this hobby, I also looked at there A10 Warthog but will probably need to improve my skills before I get that due to the size and the 80mm fans

It's a shame they don't sell a VTOL version, I'm on an aircraft carrier that operates these jets, would have been nice to also have that function

Andy

[davegee]

[QUOTE=kallend;n407857]

Somewhere in my Thingiverse stuff. Search around and you'll find it.

https://www.thingiverse.com/kallend/designs

Thanks, Kallend. I'll find it and print it up. Looking forward to it!

davegee

[kallend]

Can you explane to me how it don't matter. If you set up the model with the wheels retracted, the CG point will move backwards when the wheels come out.
I would like to think that matters, but there is nothing in the manual about whether the stated CG point on the model is when the wheels are in or out. Isn't that a important information?

1. Put a battery pack in, then test for yourself just how much the CG moves when you move the gear.

2. Right side up or upside down the CG doesn't change. Basic physics!

3. The F-35 is extremely tolerant with respect to CG position. If you're so worried, check it with the gear down.

[kallend]

[QUOTE=davegee;n407848]

I use PLA, it is actually pretty strong as long as it's not in an excessively warm location. Not good for parts exposed to the Sun in places like Texas and Arizona. if you're concerned about impact resistance PETG might be a better choice.[/QUOTE

Thanks, Kallend. Where should I look to find the STLs to do a test print of the landing gear housings, say, for the Freewing F-35A V3? That might be well worth printing up some to see how they do.

Cheers

Davegee

Somewhere in my Thingiverse stuff. Search around and you'll find it.

https://www.thingiverse.com/kallend/designs

[S.R. "Mechanic" Haugen]

Doesn't really matter.

Can you explane to me how it don't matter. If you set up the model with the wheels retracted, the CG point will move backwards when the wheels come out.
I would like to think that matters, but there is nothing in the manual about whether the stated CG point on the model is when the wheels are in or out. Isn't that a important information?

[davegee]

[QUOTE=kallend;n407219]I use PLA, it is actually pretty strong as long as it's not in an excessively warm location. Not good for parts exposed to the Sun in places like Texas and Arizona. if you're concerned about impact resistance PETG might be a better choice.[/QUOTE

Thanks, Kallend. Where should I look to find the STLs to do a test print of the landing gear housings, say, for the Freewing F-35A V3? That might be well worth printing up some to see how they do.

Cheers

Davegee

[kallend]

I'm a bit confused as to how to check the CG on the F-35. Do you check with wheels out or in, and with model upside down or right side up?

Doesn't really matter.

[S.R. "Mechanic" Haugen]

I'm a bit confused as to how to check the CG on the F-35. Do you check with wheels out or in, and with model upside down or right side up?

[kallend]

I use PLA, it is actually pretty strong as long as it's not in an excessively warm location. Not good for parts exposed to the Sun in places like Texas and Arizona. if you're concerned about impact resistance PETG might be a better choice.

[davegee]

If you compare the stock main housing with my design you will see that I have strengthened the weak area where the flange joins the body of the housing.

These landing gear housings have always been a sore spot for me in this hobby for a long time. Just the other day, I was going to take my Freewing F-15C out for a flight when I noticed in my shop that one of the main gear struts had a little more than normal "play" when I moved it. Looking closer, there was a small crack in the housing that must have happened on the previous flight. I didn't want to chance the gear failing and the damage that would cause the plane, so I put it back in the shop and ordered another gear. Grrrr!

Do you use a special material other than say, PLA ,when you print these housings, or is your design robust enough that you can just use normal materials like PLA to have a much better retract housing than stock?

Thanks,

Davegee

[kallend]

Thanks, Kallend. My retract housings for all three gear are in the mail to me and should be here sometime next week.

If you compare the stock main housing with my design you will see that I have strengthened the weak area where the flange joins the body of the housing.

[davegee]

Nice!g

I thought I had put a F-35 retract housing up on Thingy too.


EDIT: I dd for the mains but not for the nose. https://www.thingiverse.com/thing:3964037

Thanks, Kallend. My retract housings for all three gear are in the mail to me and should be here sometime next week.

I'm very impressed with your beautiful work on the afterburner nozzle for this airplane. It fit like a hand in glove when I installed it this afternoon. I hope I can learn to do some design work in 3D printing sometime soon. For the time being, I'm getting some good experience printing items like your F-35 tail piece and other projects I am displaying in my home.

Cheers

Davegee

[kallend]

I'm doing some mods on my F-35 after I had to do some repairs after a landing problem when a piece of foam strip on the bottom of the wing came out in flight. Fully repairable, although I did crack all three gear retract housings and am waiting for those to show up.

In the meantime, I printed up a better afterburner exhaust over the foam one that comes with the kit. Will be installing a RC Geek afterburner which is supposed to arrive today. Maybe next week I'll get the replacement retract units and I'll be ready to fly.

The beautifully designed afterburner tail cone was designed by our own Kallend of Hobby squawk. It came out great after I printed it up from Thingiverse. I'll attach a few pics.

Cheers

Davegee

Nice!

I thought I had put a F-35 retract housing up on Thingy too.


EDIT: I did for the mains but not for the nose. https://www.thingiverse.com/thing:3964037