Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[Evan D]

Again my opinion but no more initial issues than the F-18 (tail servos and mounting and flap servos), F-4 (elevator servo, mounting, linkage, nose gear pin and thrust line), F-104 (loose elevator horn), or the venerable Avanti (servos and flap horns coming loose) not to mention all the older BB issues...

wonder how issue free the Gripen will be, all 9g servos in it...

[Skosh25]

Don’t forget the lack of sufficient glue on the T-33 MLG. Also, no blue box in the Gripen.

[Airguardian]

Fair enough, the number we've seen is still less than 10, from probably a good few thousand flights world wide.

More like 20 I think.

Vibration from the motor causing the pin at the extension connection or at the blue box to temp disconnect or fail. Sometimes, the crimp with these thin wires maybe too tight causing a break at the connector. Check those and be happy.

It would be extremely weird IMO that BOTH elevators failed from vibration at the same time... on several aircraft.

[Wefinance01]

More like 20 I think.



It would be extremely weird IMO that BOTH elevators failed from vibration at the same time... on several aircraft.

Not really..I've had it happen on other jets where the connection from the y connection before the split sonic vibration does a nice job on pin connectors that are over crimped. I've had it happen also on my 120cc SBACH on smart fly expander.

[RCMustang]

I few my Mig yesterday and did a few passes with the throttle at between 75 and 100 percent and with half flaps. I definitely noticed a tendency for the nose to drop and had to pull quite a bit more on the elevator to keep the nose level. It was more pronounced when I came out of a turn and coming towards me. As soon as I got rid of flaps or reduced throttle the tendency was gone. I did not rigorously test this, but I certainly was aware of it. A less experienced or nervous pilot could certainly interpret this as an aerodynamic issue or loss of a control surface. I certainly think part of this is pilot error. I'm flying with the upgrades servos, chokes, CG back, etc and it flies fine. It certainly makes an impression at the field with pilots that have not seen it before. Even the turbine guys think it's a cool EDF.

[AirHead]

Well, it is real. Many seem to have crashed, especially early on for simply not reading the instructions especially the elevator push rod location and balance. But there have been others and many have not been able to come to a singular reason. While many are saying the sky is falling and running around like chicken little I think many are for more normal reasons like piloting error. I really think at the end of the day there have been no higher a percentage than other planes. I think the cost of this plane really brings it to a higher awareness.

All my opinion though...

"I think the cost of this plane really brings it to a higher awareness"...Yes, it certainly does. I can't afford these beasts due to car repairs, mortgage, etc. If Dynam had built this plane, most would understand. I can't believe the issues with this model. Even though many around the world consider that we are at the "bottom end" of the model aircraft hobby flying "foam airplanes", it's still a "big crunch" to the wallet when a "foamie" goes down with all it's expensive innards...Hopefully the issues will iron out....

[Evan D]

Agreed, and add an exchange rate...

I was going to add TVs and two 8s setups until I added up the amount that would be flying around, $1400... Not including batteries.

[Jet jocky]

Who posted on how to make the gear cover to go up when the gear are extended. Can't find in the posts on how to do it. Thanks

[Evan D]

I’ve done it but I removed the ribbon cables and used extensions and a Y to the dual action slot on the MCBe. Someone showed how to mod the ribbon cables... might have been on RCG.

[themudduck]

Who posted on how to make the gear cover to go up when the gear are extended. Can't find in the posts on how to do it. Thanks

It was not on RC Groups, it was here. There were a few posts about it. See post #926 - Dated Sept 12. There's a picture.
The blue box has a "dual stage" input, plug your doors there and they will close after the landing gear comes down.
The problem is that the LG door servo connections are in the ribbon cable. You can re-route them from the wing but that makes the wing harder to install. So the easiest way is to remove one signal wire out of each ribbon cable, "Y" them into a connector, and plug the connector into the dual-stage port on the blue box like you see on post 926.

[GliderGuy]

Who posted on how to make the gear cover to go up when the gear are extended. Can't find in the posts on how to do it. Thanks

Also see post # 1391 for added follow up.

-GG

[Jet jocky]

Thanks guys.

[PieterO]

I don't guess anyone is listening but this is a very good point. Why both elevators non-responsive at the same time. Two tunnels and two sets of servo leads. We should be seeing planes doing uncommanded rolls, etc when one servo loses signal and the other is still responding. The odds of both servos simultaneously losing signal seems pretty remote to me.

Yes, I agree (so also thanks to Hugh Wiedman who brought this up initially). If both elevators fail at the same time due to some technical issue, it must be something that both elevators have in common. It could be the blue box, but I already read about many people using the Y cable to directly plug into the receiver. Then the only common part is the connector on the Y-cable that goes into the receiver. But is seems odd to me that this would fail.

Or, just thinking: the RF noise could go via one cable, via the Y cable, into the other one, therefore impacting both servo's at the same time. Not sure of this is possible.

[Firebird]

Yes, I agree (so also thanks to Hugh Wiedman who brought this up initially). If both elevators fail at the same time due to some technical issue, it must be something that both elevators have in common. It could be the blue box, but I already read about many people using the Y cable to directly plug into the receiver. Then the only common part is the connector on the Y-cable that goes into the receiver. But is seems odd to me that this would fail.

Or, just thinking: the RF noise could go via one cable, via the Y cable, into the other one, therefore impacting both servo's at the same time. Not sure of this is possible.

Pieter, i fully agree with your statement. The problem ist in between the receiver out and the servos. Either the signal gets disturbed by RF influence (disturbance spreading via y-cable into both servos), the voltage drops under certain conditions (flaps extended) at the elevator servo due to under dimensioned elevator cables, Y-cable or the y-cable itself loses contact temporarily or the servo’s overheat in certain conditions while fighting continuesly nose down moment.

Whatever the cause is at the end - the servos might enter fail save mode for a moment causing the the stabilizers moving back to aerodynamic center position - leading in the aircraft following the nose down moment and causing the dive.

[GliderGuy]

Anxiously waiting for the telemetry from Firebird’s Hacker servos....

If the signal noise is at the end, then adding chokes at the servos should attenuate it. There is plenty of room for the small barrel-type clip on chokes. I won’t know if these help because I wasn’t having issues. But, now....less likely to have issues, if noise at the end is the culprit.

The photo is looking down on the inverted bird...the servo is on the lower right after being pulled out. Next step was to tuck in the choke, remount the servo and position it for trim alignment so both servos match on the trim setting. They can move fore and aft a bit, so alignment had to be re-done.

All this can be done without disconnecting the push rod as I found out “after” doing this first one.

Hint: Leave a couple of cm space between the choke and servo....helps with the re-mounting process.
-GG

[robertbulko]

Well, no one was interested in my recent post, where I was talking about electrical current as a potential cause of Elevator issue. So far, I can clearly see the problem could be the el. current or interference. I believe, it might not be the interference because only or mostly Elevators are affected. This MiG is big so the Elevators are larger and in a high speed the servos controlling them have probably really hard time and the el. current consumption is high. Maybe, the Rx or Blue box are no able to handle it. Maybe the additional power source for your servos will be the solution. ;)

Only signal cables could go via blue box and the rest via some power box or whatever you call it + maybe using thicker cables will help.

[Jacckall]

Hello from Slovakia!

Slovak Air Force!

Vodochody Aero L-39 Albatros - over 400 flights
Mikoyan Gurevich Mig-29 Fulcrum - 7 flights

[viper1gj]

Yeah roger that, and I've already taken that in consideration. Unfortunately the way the model is made the rear tank are can barely fit a 21oz tank and the center area option can only fit a smaller 12-14oz tank max and still have the ability to close the top canopy hatch. When flying with 2 X-45's you need at least a total of 48oz if you want to get 3-3.5 min of useful flight time. I have a total of 45oz. The fuel burn will be a lot lower as flying at half throttle will lengthen the total flight time by 40% or so. CG isn't an issue as the forward tank burns off first and and the rear last, so when it comes time for lading she will land slower and lighter than the EDF version. I'm using NO UAT, just s felt tip clink in the rear tank, and a regular clunk in the forward tank.

Following your turbine conversion closely as a friend and I are doing the same with single K-45G3. Yours looks great. I would like to pick your brain possible for how you did stuff.

Do you have any photos of the turbine install?
What brand and size is your rear tank?
Did you 3D print the center line tank and rocket pods? If so would you share your files?
How is the center line tank attached to the fuse?

Thanks,
Gary

[Gringotuerto]

...Hello from Slovakia!...

Hey that is awesome! Now you just need an F-16V. Or a Let L-410.

[GliderGuy]

Well...recent post....

So much remains unknown at this point. We’ll have REAL data when Firebird installs the HACKER servos and looks at the telemetry data they provide. Pretty much conjecture until then.

-GG