Official Freewing Twin 80mm F-14D Tomcat Thread

[thisguy65]

So I decided to start this little project. I was able to find an L-shaped aluminum bar stock, a couple of High Torque Savox standard size servos (which includes the metal servo arm). I was able to construct a bracket and base the mounting holes on the standard out-of-the-box bracket. I was able to get everything to fit and programed the mid-sweep and tied it to my flight mode switch. The servos pictured here are not the final ones I used, these though we strong had no holding power. I did manage to maiden my F-14 with this mod and was successful. I'll try to get some video of the flight when I get back from my business trip.

https://www.youtube.com/shorts/E9WcSrVxeKc

https://www.youtube.com/shorts/iY5Lbjx9gE0

Cheers,
Vic

Nice work Vic!

I kept help but ask, is it ok for the servos to be buzzing that much?

[vicentel]

Nice work Vic!

I kept help but ask, is it ok for the servos to be buzzing that much?

It's actually louder when the servos are under load. But that buzzing is there even when the servos are not under load and it only happens at the endpoints. Someone mentioned that it was the servos holding their position, but I don't hear the buzzing when the servos are in their mid position. So I'm not sure. This is also my first time using high torque steering servos for this application so I don't have much experience with them. Thoughts?

Vic

[RRHandy]

It's actually louder when the servos are under load. But that buzzing is there even when the servos are not under load and it only happens at the endpoints. Someone mentioned that it was the servos holding their position, but I don't hear the buzzing when the servos are in their mid position. So I'm not sure. This is also my first time using high torque steering servos for this application so I don't have much experience with them. Thoughts?

Vic

There might be some binding at the end of the stroke and the servo is tying to hold it at that position, or the wings are at full movement and the servos are over driving them. check it out.

R.

[vicentel]

There might be some binding at the end of the stroke and the servo is tying to hold it at that position, or the wings are at full movement and the servos are over driving them. check it out.

R.

I checked that the wings are at full movement and the servos are not trying to push them past their limits, at both end points. I use to have the ball ends on top of the servo horn but it was causing binding (twisting) and one of the endpoints so I moved the ball end to the bottom of the servo horn.

[Evan D]

Very interesting what you are doing, removing the retract type "servos" that are only two position and replacing them with high torque servos to get more than two positions of wing sweep. The original retract servos "lock" at their end points to give holding power. You are relying on the servo to have sufficient holding power.

What servos did you end up using? Are you sure that moving the ball link under the servo arm isn't causing issues?

In your video you had 180deg travel servos moving less than 90deg for the full sweep. A servo can provide much more torque and resolution having the ball link closer to the servo shaft. That may be something to consider. Also if the servo turns to the point that the servo arm is more in line with the push rod it has more holding power. when the arm is 90deg to the pushrod it has the least amount of holding power. Any more pictures or videos?

[vicentel]

Very interesting what you are doing, removing the retract type "servos" that are only two position and replacing them with high torque servos to get more than two positions of wing sweep. The original retract servos "lock" at their end points to give holding power. You are relying on the servo to have sufficient holding power.

What servos did you end up using? Are you sure that moving the ball link under the servo arm isn't causing issues?

In your video you had 180deg travel servos moving less than 90deg for the full sweep. A servo can provide much more torque and resolution having the ball link closer to the servo shaft. That may be something to consider. Also if the servo turns to the point that the servo arm is more in line with the push rod it has more holding power. when the arm is 90deg to the pushrod it has the least amount of holding power. Any more pictures or videos?

I ended up using Savox SW1212SG-BE - Waterproof, High Torque, High Voltage Coreless Digital Servo rated at 36kg @6V. If I wanted to dedicate a 2S Lipo pack then the torque goes up to 46kg. But I figured 36kg is more than enough for this application.

From the Savox support site FAQ:
Q. Why does my Savox servo buzz?
A. The buzzing sound is created by the servo constantly making corrections to hold it's position. It is normal with digital servos, but some servos are louder than others.

I am using a shorter servo arm compared to the one used by Freewing (std is 1.25" center hole to ball-link) for the reasons you outlined (more torque higher resolution). I've had 3 successful flights so far. I was monitoring battery usage to see if the high torque servos put too much of a drain on the battery feeding the ubec. But so far the battery drain is negligible. What I would like to do (eventually after much testing) is setup a mix with the swing servos and the throttle (with a delay so the change in the sweep doesn't jerk the wings), keep the endpoint override for landing purposes.

Cheers
Vic

[rifleman_btx]

Storing trims for flight modes?

Yes, that is what I was referring to.

[primodus22]

Got the maiden done on the F-14 Tomcat this morning before the winds picked up. Super smooth and stable model. I’ve got a little trim adjustment to make on the elevator (it was diving heavily), but it trimmed out nicely and landing was a greaser on the mains. I did not sweep the wings on maiden to keep it simple and I look forward to the next time I get to take it up. She’s got a great presence in the air and plenty of power for such a large plane. All stock and I’m hooked.

[kallend]

Got the maiden done on the F-14 Tomcat this morning before the winds picked up. Super smooth and stable model. I’ve got a little trim adjustment to make on the elevator (it was diving heavily), but it trimmed out nicely and landing was a greaser on the mains. I did not sweep the wings on maiden to keep it simple and I look forward to the next time I get to take it up. She’s got a great presence in the air and plenty of power for such a large plane. All stock and I’m hooked.

Nice.

What power system do you have in there?

[primodus22]

All stock on two RCBattery 6s 5000.

[kallend]

My club did a static show at Daley Plaza in downtown Chicago today, right in front of the huge Picasso sculpture. The F-14 got a lot of attention, especially when I taxied it around the plaza and lit up the "afterburners". .

[vicentel]

Once I maidened my F-14 I decided to refinish it with the Wolfpack VF-1 livery. I 3D printed the ordinance (2xSidewinders, 2xAIMs, 4xPhoenix). I redid the undercarriage using a 1.5mm ABS plate with naca inlets. I fashioned anther set of missile rails for the additional 2 Phoenix missiles. The Wolfpack graphics were sourced from Callie Graphics. it's still a work-in-progress but I thought I'd share where I am in my build.

Cheers,
Vic

[Nfun]

Once I maidened my F-14 I decided to refinish it with the Wolfpack VF-1 livery. I 3D printed the ordinance (2xSidewinders, 2xAIMs, 4xPhoenix). I redid the undercarriage using a 1.5mm ABS plate with naca inlets. I fashioned anther set of missile rails for the additional 2 Phoenix missiles. The Wolfpack graphics were sourced from Callie Graphics. it's still a work-in-progress but I thought I'd share where I am in my build.

Cheers,
Vic

what main struts did you use on this?

[Elbee]

Once I maidened my F-14 I decided to refinish it with the Wolfpack VF-1 livery. it's still a work-in-progress but I thought I'd share where I am in my build.

VC, nicely done, beautiful repaint. Diggin' all the 3DP parts and your choice of livery. Bravo Zulu, Sir. Best, LB

[vicentel]

what main struts did you use on this?

These are the F4U 60-120 Eflite struts, E-flite - EFLG520F4U (https://www.horizonhobby.com/product...FLG520F4U.html) mated to the Eflite 25-45 90deg. retract set.

[Big12fan]

Just installed a new power system and landing gear. Out with the FMS 2100kv units and in with some Jetfan V3 fans and HET 700-68-2250kv motors. Controlling them are Hobbywing 120a ESCs with 150a burst capacity. These motors are a combined ~350g heavier than the FMS units. I'm coming out a touch tail heavy even with my heaviest batteries (~800g/ea) ALL the way forward! I know it can be flown like this though.

I also installed the E-Flite 25-46 90 degree retracts with the trunnions drilled out to accept the 5.1mm pins from the stock struts. I added Robart 2.75" rubber wheels and RC Geek 3D printed hub caps. They look amazing!

How come you went away from the 2100 kv set up?

[kallend]

How come you went away from the 2100 kv set up?

That post was 4 months ago and we never heard the outcome. I'm **guessing** the experiment was not a great success.

[Big12fan]

That post was 4 months ago and we never heard the outcome. I'm **guessing** the experiment was not a great success.

Hmmm, yeah, cause I was thinking of putting those in mine since I have 2 sitting around. I love how the 2100’s awakened my eflite and FMS 80 mm jets.

[kallend]

Hmmm, yeah, cause I was thinking of putting those in mine since I have 2 sitting around. I love how the 2100’s awakened my eflite and FMS 80 mm jets.

I have the FMS 2100s in mine and it's much livelier than the stock setup.

[vicentel]

I have the FMS 2100s in mine and it's much livelier than the stock setup.

I'm running the stock MiG-29 power system (EDFs and 100amp ESCs) in my F-14. Also, I'm running the FMS 80mm V3 12 Blade Pro 3665 2000Kv EDF For 6S in my MiG-29 and they give me a lot of static thrust. I was thinking of swapping out what I currently have in my F-14 for the new FMS 80mm V3 12 Blade Pro 3665 2000Kv EDFs.I would just have to modify the mounting holes in the F-14 since they're in different locations on the EDF.