Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[kallend]

Already knew that, just testing a theory to see if static balance could be achieved. As I stated, would require to much weight as the pivot point is to far forward. The MIG flies well and I like it.

As most recently pointed out by Themudduck, a lot of people have said how well this plane flies, right up to the point where it didn't.

[Raydar]

I still think its a servo issue only, sure other upgrades will improve the plane but the elevator servos are causing the fatalities. This can be a cheap fix for Freewing, redesign the plastic elevator servo mount to take a bigger higher spec servo then cut the original fuse at build to accept it. Upgraded linkage (that they already produce) would prob finish the job. If nothing else it would build confidence in the plane and they can get back to making and selling them.

[ColtPilot]

As most recently pointed out by Themudduck, a lot of people have said how well this plane flies, right up to the point where it didn't.

Risk and reward. Nature of the hobby.

[Gringotuerto]

Then I went home and changed my pants~! ....... Why would only the elevator servos stop, both at the same time? (and yes I bypassed the blue box for the elevators)

1. The only mod that everyone seems to agree on is that you need to install stronger underwear.

2. I also wondered why both independent servos would be affected at the same time. I haven't read every single post, but have read many and don't recall any report of one side moving and the other not moving, so that the plane starts spiraling. Anybody experienced that? If it is IR drop over a long wire, that still doesn't really explain the simultaneous nature because the wires split all the way back at the Rx (if you use the y-cable they provide with the model).

I think it is something like the following: imagine the servos are very near their maximum load. Then you give more up elevator. One servo is very slightly stronger. The weaker one doesn’t move, but the stronger one starts to. Once the stronger one moves a fraction of a millimeter, its load increases, whereas the weaker one is still experiencing the same load. Since they are approximately the same, quickly the stronger one will hit its limit and stop moving also.

So in other words, two paths of the same design are never going to match 100%, but they should be within maybe a couple percent. And that is probably good enough for them to stall at approximately the same position, for the reason explained above – the one that is a couple percent stronger will quickly experience a couple percent more load.

[ColtPilot]

1. The only mod that everyone seems to agree on is that you need to install stronger underwear.

2. I also wondered why both independent servos would be affected at the same time. I haven't read every single post, but have read many and don't recall any report of one side moving and the other not moving, so that the plane starts spiraling. Anybody experienced that? If it is IR drop over a long wire, that still doesn't really explain the simultaneous nature because the wires split all the way back at the Rx (if you use the y-cable they provide with the model).

I think it is something like the following: imagine the servos are very near their maximum load. Then you give more up elevator. One servo is very slightly stronger. The weaker one doesn’t move, but the stronger one starts to. Once the stronger one moves a fraction of a millimeter, its load increases, whereas the weaker one is still experiencing the same load. Since they are approximately the same, quickly the stronger one will hit its limit and stop moving also.

So in other words, two paths of the same design are never going to match 100%, but they should be within maybe a couple percent. And that is probably good enough for them to stall at approximately the same position, for the reason explained above – the one that is a couple percent stronger will quickly experience a couple percent more load.

I know it's really tight getting those servos in and can easily pinch the wires which could possibly cause an issue. Just a guess. I was really careful putting the new servos in feeding the wires in as much as possible then putting the servo in the space. Thoughts?

[GliderGuy]

No room to take the MiG in my truck, but wanted to show y'all what is possible...when you are an airplane nut.

It was a cool day, but light winds and sunny. Waited until the temp got above freezing before going out (45F+ suites my old bones better and is better for the LiPos...so I read).

Beat my personal best of 40 flights in one day with 47 total flights today. Was using 3 of the 4-bank (4 X 100W) chargers and 16 batteries (10 6S and 6 4S) powered by my truck's heavy duty electrical system. Nobody stopped by the baseball park's parking lot to chat (that's unusual).

The break-out of the flights is as follows:

AL37 = 34 flights (This is a brand new bird...not even a week old. Maiden was on 01/13. After today she already has 60 flights on her.) I retired AL37 #1.
F-4 = 4 flights
P-38 = 9 flights

I'm bushed! But it was sure fun!. I love this hobby. The MiG's day will be tomorrow, if the wind cooperates.

-GG

[GliderGuy]

I know it's really tight getting those servos in and can easily pinch the wires which could possibly cause an issue. Just a guess. I was really careful putting the new servos in feeding the wires in as much as possible then putting the servo in the space. Thoughts?

I also elected to go with a drop-in servo that has higher torque and lower operating voltage functionality to add margin against potential failure. I agree....getting these "drop in" servos to go into the hole w/o modifying the hole was a trick. It was possible, but tricky not to pinch the servo wire. I almost broke out the Dremel grinder.

My modifications in the rear end also included the following:

- Larger diameter (0.5 mm or 22 AWG wire from the short FW-supplied "Y" to the tail servos) to lessen the IR drop, since the upgrade / higher torque servos draw more current
- There was room for a small RF choke ahead (to the front) of each tail servo. What the heck...it couldn't hurt, so each servo driving the FFSs has an RF choke on it to block any electrical noise that might be heading to the rear servos (see photo below)
- 0.5 mm carbon sheeting added to the bottom of the fuselage by the FFSs. Not so much to stiffen the area, but to prevent the plastic rectangular box from separating from the foam. Someone mentioned this glue joint potential for fatigue, so I made sure the plastic box holding the FFSs will stay put (see photo below).

Other modifications were done up front and detailed in prior posts.

-GG

P.S. Still having good luck with the Futaba SR-10 servo reverser. I reckon it'll work until it doesn't. Very stable position wise with temperature changes.

[leithalweapon]

I still think its a servo issue only, sure other upgrades will improve the plane but the elevator servos are causing the fatalities. This can be a cheap fix for Freewing, redesign the plastic elevator servo mount to take a bigger higher spec servo then cut the original fuse at build to accept it. Upgraded linkage (that they already produce) would prob finish the job. If nothing else it would build confidence in the plane and they can get back to making and selling them.

If they rework the original mold to accept a larger servo box that would solve most of the problem. Maybe then they could produce enough extra modified fuselages to sell to anyone who got an original one. At cost of course

[t33jetman]

About twenty thousand more revits to go , so crank up the music.

[Airguardian]

That's badass.

[t33jetman]

kip

[Elbee]

About twenty thousand more revits to go,

Т33, МиГ, Малютка. Браво Зулу, сэр. Приветствия, LB

[AirHead]

I think that the facilitators at Hobby Squawk should install a separate server for this thread. It never ends...

[Justwingit]

Justin Link's superb looking repaint of the MiG-29 Fulcrum in East German livery...😎

The level of detail Justin did to this is simply outstanding! I hung out with him in his shop and watched as he put in several of the HUNDREDS of sunk rivets that are in the model, all of them in factory locations using close-up photos. It's painstaking work for sure, but man does it really look the part 😁!

[4qr1hu9n7]

Risk and reward. Nature of the hobby.

Simple. Just stop doing the full speed dive . No need for these ridiculous elevator servo upgrades. Next step will be to install 300 ounce torque servos.

[kallend]

Simple. Just stop doing the full speed dive . No need for these ridiculous elevator servo upgrades. Next step will be to install 300 ounce torque servos.

Please explain why remedying a design deficiency is "ridiculous" but constraining the performance envelope makes sense.

[steven gubala]

Hello t33 Jetman, what tool did you use the do the raised rivets, great job

[t33jetman]

Hello t33 Jetman, what tool did you use the do the raised rivets, great job

I use a these two glues mixed together and a bottle with a fine metal tip from Hobby Lobby.

[t33jetman]

I also have a host of other revit making tools used from time to time.

the

[mshagg]

How do you find those rivet wheels Jetman? I'm about to tackle the freewing A10 and was going to try that technique to dress it up some. I dont think I have the craftsmanship yet to tackle the glue technique, you've been at this a lot longer :)