Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[xviper]

The one with the Promodeler DS100 servos almost crashed on flight no 2 - NO ELEVATOR ! The issue is the servo. The DS100 is a HV servo and operating it at 5.1V is on the lower end of the performance (speed and torque). I have the footage below FYI..

https://youtu.be/LATWowGFfrI

https://youtu.be/Hq2pKcHg3U4

https://youtu.be/z6S1EonBIcQ

https://youtu.be/sxxQ47QejXs

YIKES!

[Captain MoMo]

YIKES!

My feelings exactly when it happened! But Mike caught the whole thing on his camera - I did not pull back on the elevator too much as it would have stalled for sure - let go on the pressure and after she stabilized slightly I pull up again and returned home. It was a few seconds of my life gone 😁

[JohnVH]

As fast as it was I dont think it would have stalled, second flight on my mig with the original stock servos I did a loop too low, and was full up elevator to not hit the groud, worked out great for me, fortunately. haha. I do have the upgraded servos in mine, but still contemplating putting in something bigger, just for peace of mind. I flew mine on stock servos a bunch with no problems.

@1:40

https://www.youtube.com/watch?v=oXjHzozH6bI&t

[leithalweapon]

Good question to ask for sure - but I think that flaps are not the root cause. The root cause is most likely the inability of the elevator servos to handle the extra load due to flaps down at high speed. If the servos are replaced with a more powerful and capable set you will probably not crash due to loss of elevator - you may crash still but due to some other issue 😉

Fixx the pilot not the plane. That way you won't fly any plane at high speed with the flaps down. It just isn't a good idea and is a bad habit for sure.
You only have to fix one pilot.

[xviper]

My feelings exactly when it happened! But Mike caught the whole thing on his camera - I did not pull back on the elevator too much as it would have stalled for sure - let go on the pressure and after she stabilized slightly I pull up again and returned home. It was a few seconds of my life gone 😁

Is video 1 and video 2 the same flight? I wasn't quite sure if I got the time stamp correct. I wanted to see at the same moment it lost ELE in video one, what it looked like from the onboard in video 2.

[Captain MoMo]

As fast as it was I dont think it would have stalled, second flight on my mig with the original stock servos I did a loop too low, and was full up elevator to not hit the groud, worked out great for me, fortunately. haha. I do have the upgraded servos in mine, but still contemplating putting in something bigger, just for peace of mind. I flew mine on stock servos a bunch with no problems.

@1:40
https://www.youtube.com/watch?v=oXjHzozH6bI&t

That was close! LOL

Yes, stock 23g servos should work on paper and it looks like many folks are doing ok with them - just some are having issues. I don't doubt anyone who has a problem with the stock 23g servos - its hard to have your trust in a servo that you know has failed on others and yourself before. My recommendation is to swap out servos to better ones and move on - this bird is simply fantastic for it to be a hangar queen.

[JohnVH]

That was close! LOL

Yes, stock 23g servos should work on paper and it looks like many folks are doing ok with them - just some are having issues. I don't doubt anyone who has a problem with the stock 23g servos - its hard to have your trust in a servo that you know has failed on others and yourself before. My recommendation is to swap out servos to better ones and move on - this bird is simply fantastic for it to be a hangar queen.

This was on the 18g or whatever the stock ones were. Ive been flying it, Im not afraid of it, I wonder how many were a radio problem and not a plane problem.

[Captain MoMo]

Fixx the pilot not the plane. That way you won't fly any plane at high speed with the flaps down. It just isn't a good idea and is a bad habit for sure.
You only have to fix one pilot.

Yeah - true. I am unfixable 😁 But seriously - the flaps are not the issue.

[Captain MoMo]

Is video 1 and video 2 the same flight? I wasn't quite sure if I got the time stamp correct. I wanted to see at the same moment it lost ELE in video one, what it looked like from the onboard in video 2.

The one that has a loss of elevator is the first video with my V2 model - in the YT description I explain. The other videos are all of my V1 Mig 29, including view of elevator servo (Hitec D85MG), linkages and general view of the model. Absolutely enjoyed flying the V1 Mig 29 - she is a keeper.

[Captain MoMo]

This was on the 18g or whatever the stock ones were. Ive been flying it, Im not afraid of it, I wonder how many were a radio problem and not a plane problem.

You are one of the lucky ones then - but considering that the same servo (17g) is used on the F22 90mm, I am not surprised.

[JohnVH]

You are one of the lucky ones then - but considering that the same servo (17g) is used on the F22 90mm, I am not surprised.

Maybe, flew it 4 times on the stock servos before the upgraded ones showed up.

[Evan D]

I maidened +2 mine with the stock original servos but did put the pushrod (stock) on the inner hole.

From my poll 14 have answered 11 had the upgraded FW servos, 2 had the stock FW servos, 1 didn't say. I agree with those that say the upgrades are on the edge of good enough but I have to say that upgrading the pushrod is as important and flying with common sense (no high speed flap down flying) is essential. And last not being any more nose heavy than the cg line on the wing and even better 10-15mm behind it. Reflex also seems to be a good idea.

[RudyD54]

Xviper -that is exactly what I am concluding. Or perhaps some of the Freewing upgraded 23g servos are not meeting their specs (or are mixed up with 17g servos as they look the same with no markings) while others are just fine. I just flew two Migs - all built with the same mods except the servos. One had the Hitec D85MGs and the other the Promodeler DS100. The one with the Hitec servos at 5.1V performed fantastic and flew 8 flights of excruciating abuse (including full throttle with flaps) and survived. The one with the Promodeler DS100 servos almost crashed on flight no 2 - NO ELEVATOR ! The issue is the servo. The DS100 is a HV servo and operating it at 5.1V is on the lower end of the performance (speed and torque). I have the footage below FYI..

https://youtu.be/LATWowGFfrI

https://youtu.be/Hq2pKcHg3U4

https://youtu.be/z6S1EonBIcQ

https://youtu.be/sxxQ47QejXs

That’s interesting as the promodeler claims higher torque (70oz@4.8v) than the hitec d85mg(50oz@4.8v). 🤔

[GliderGuy]

For comparison....exact drop in, but those with 6 ch radios will need a reverser. MKS doesn’t offer a reverse version. Source: MKS website

I bought these because 1) Drop in 2) 3.7 volt min operating spec to cover any voltage drop in the tail.

-GG

SKU	MKS-HV69
Quantity in stock	91 item(s) available
Dead Band	0.001ms (Default)
Spline Size	6mm 25 Tooth
Control System	+Pulse Width Control
Working Frequence	1520μs / 333Hz
Operating Voltage	3.7 ~ 8.2 V DC Volts (for 2S ~ 1S LiPo)
Operating Temperature Range	-10 to + 60 Degree C
Operating Speed (4.8V)	0.17 sec/60° degrees at no load
Operating Speed (6V)	0.13 sec/60° degrees at no load
Stall Torque (4.8V)	6.0 kg-cm / 83.3 oz-in
Operating Speed (7.4V)	0.11 sec/60° degrees at no load
Operating Speed (8.4V)	0.10 sec/60° degrees at no load
Stall Torque (6V)	7.50 kg/cm (104.2 oz/in)
Stall Torque (7.4V)	9.2 Kg/cm (127.8 oz/in)
Stall Torque (8.4V)	10.2 Kg/cm (141.7 oz/in)
Motor Type	Coreless Motor
Potentiometer Drive	Direct Drive
Bearing Type	2x Ball bearing
Gear Type	Metal Alloy Gear
Dimensions	29 x 13 x 28.7 mm
Weight	21 g

[Captain MoMo]

That’s interesting as the promodeler claims higher torque (70oz@4.8v) than the hitec d85mg(50oz@4.8v). 🤔

Who knows.... I don't know why and all I can say is that there are many variables.

[Captain MoMo]

For comparison....exact drop in, but those with 6 ch radios will need a reverser. MKS doesn’t offer a reverse version. Source: MKS website

I bought these because 1) Drop in 2) 3.7 volt min operating spec to cover any voltage drop in the tail.

-GG

SKU	MKS-HV69
Quantity in stock	91 item(s) available
Dead Band	0.001ms (Default)
Spline Size	6mm 25 Tooth
Control System	+Pulse Width Control
Working Frequence	1520μs / 333Hz
Operating Voltage	3.7 ~ 8.2 V DC Volts (for 2S ~ 1S LiPo)
Operating Temperature Range	-10 to + 60 Degree C
Operating Speed (4.8V)	0.17 sec/60° degrees at no load
Operating Speed (6V)	0.13 sec/60° degrees at no load
Stall Torque (4.8V)	6.0 kg-cm / 83.3 oz-in
Operating Speed (7.4V)	0.11 sec/60° degrees at no load
Operating Speed (8.4V)	0.10 sec/60° degrees at no load
Stall Torque (6V)	7.50 kg/cm (104.2 oz/in)
Stall Torque (7.4V)	9.2 Kg/cm (127.8 oz/in)
Stall Torque (8.4V)	10.2 Kg/cm (141.7 oz/in)
Motor Type	Coreless Motor
Potentiometer Drive	Direct Drive
Bearing Type	2x Ball bearing
Gear Type	Metal Alloy Gear
Dimensions	29 x 13 x 28.7 mm
Weight	21 g

Do you use a gyro? If yes, will the reverser have any effect on gyro performance?

[bandetx]

It's not that hard to reverse a servo. Just open it up and swap the wires. Plenty of videos on youtube about reversing a servo.

[GliderGuy]

1) No gyro...so I don’t know
2) I had to reverse/re-wire one of the MRC-supplied upgrade servos. Both that they sent me were positive direction servos. I decided to not re-wire one of the HV69 servos. That’s some tight soldering spaces. I did it, but I wouldn’t say it was EASY due to the tight space.

I went with a Futaba SR-10 reverser and am happy with it. Happier than with the soldering I would have had to do again....and then loose sleep over.

Some advise against reversers....so, to each his own. I would not classify the SR-10 as a low quality solution. It has a lot of features not found on cheap solutions.


-GG

[leithalweapon]

Yeah - true. I am unfixable 😁 But seriously - the flaps are not the issue.

They are when you fly to fast with them down.

[Airguardian]

I will just say that those using the stabs only for pitch on this jet are offending the Gods and will burn in hell for eternity.