Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[Eric D]

Hi I just got my Mig 29. It came with elevator servos y'd to go direct to rx. I don't know if the servos are different but the extensions are 26 gauge. I will put HT 5245 servos and heavier extensions.

[john2kx]

I had a couple of guys reach out to me concerning the crash of my MiG 29. They thought it best to “start a ticket” with MRC. I’ve had a dozen of their jets and never a issue. Having rethought this, I have filed a ticket in hopes it can help everyone else. Now, I feel like a orphan. I’ve got a handful of siblings with weird names😝.

[Gringotuerto]

The Dictator is ready to try again! As you may remember, Kim Jong Un's first adventure did not go well. Those responsible have been executed. This time, I decided to take a little more time and copy the livery of one of the few photos actually available from DPRK. Clear the skies tomorrow, or be prepared to receive Laughing Kim's fire and fury! You have been warned!

[AirHead]

The Dictator is ready to try again! As you may remember, Kim Jong Un's first adventure did not go well. Those responsible have been executed. This time, I decided to take a little more time and copy the livery of one of the few photos actually available from DPRK. Clear the skies tomorrow, or be prepared to receive Laughing Kim's fire and fury! You have been warned!

Hahahahahahahaha....LMAO! Hilarious. Hope it flies right!.....

[mshagg]

Dear Leader will make the most wonderful maiden. Anyone saying otherwise is clearly American spy!

[Captain MoMo]

Firebird, Evan, GG and others - thanks for all your analysis and testing.

[nuts-n-volts]

Firebird, awesome testing. I think it shows a lot. I'm wondering again and guessing that if flaps were lowered and stalled or close to it, that same voltage drop could be assumed to be applied to the elevators. (The voltage is affected across the whole system) Also, if the elevators are taking on their own load, the total voltage drop would be even greater?

[GliderGuy]

Will someone with large scale aircraft experience or otherwise study the data Firebird took.

It seems that the MRC servos can provide quite respectable force while still keeping within the min ROC of the servo (4.8 V).

Thanks,
-GG

[GliderGuy]

Firebird, awesome testing. I think it shows a lot. I'm wondering again and guessing that if flaps were lowered and stalled or close to it, that same voltage drop could be assumed to be applied to the elevators. (The voltage is affected across the whole system) Also, if the elevators are taking on their own load, the total voltage drop would be even greater?

The voltage Firebird reported was read at the servo. The voltage elsewhere will be a higher value since it is ahead of the long servo wires.

Ex: 5.1V at UBEC will be about 0.39V less at the servo (values depend on wire resistance and servo current.

-GG

[viper1gj]

Mig-29, canopy opening modification.
No 3D parts, no help, lots of cardboard and balsa and glue, and just old fashion gray matter and lots of coffee and sleep.

That is totally awesome! I love it. Can you post pics of your design and fabrication?
Thanks

[viper1gj]

From all this I think a good thing to consider is upping the voltage from the BEC to 5.5 or MAYBE even 6.0V. Since the stock BEC is not adjustable this would require a different, why not 10A or higher, BEC.
But at a minimum we should consider a higher torque servo than the FW upgrade, stronger push rods, better/ shorter extensions, and going directly to individual slots on the receiver with a mix. Also I think everyone should swap the stab horns with as long a screw as they can use and glue the horn down, use better ball links on the better push rod with washers outboard of the ball as a safety incase they pop off due to the angle, and NOT have the elevator servo arm at 90 degrees to the fuselage but at 90 degrees to the push rod.

Agree. This is exactly how I am setting up mine. 5.7v from BEC, Powerbox Maxi wire elevator extensions, and all the rest you said. Also considering a longer control horn on the stabs.

[Hugh Wiedman]

I promised someone a while back I’d send some pics of the MiG in my Mini Cooper. Well, may I present MiG-29 and F-22 in the back of a Mini Cooper. 😂
Finally got some decent weather so I’m on the way to meet Hugh Wiedman at the field for the maiden. I’ll report back and let y’all know how it went. 😳👏🏼🤞🏼

Hey I got my Mig out for a maiden and 3 flights. It's kind on puny compared to my A-10 though!



OK, OK, it's not mine. It's RudyD54 Mig (but when he's not looking I'm going to snatch it-he won't miss it crammed in that Mini Cooper). He flew it great, I'll upload a video of a couple flights tomorrow or Sunday. His missiles look awesome and it was a VERY successful day for him. He's definitely got some cajones flying it after several hours of rain resulting in wet grass, but it got off great, although the first couple take-offs it looked like the Space Shuttle blasting off. And he flew it from the get go fully loaded. I'll let him break down his set-up and how it flew.

[sfcfury]

The Dictator is ready to try again! As you may remember, Kim Jong Un's first adventure did not go well. Those responsible have been executed. This time, I decided to take a little more time and copy the livery of one of the few photos actually available from DPRK. Clear the skies tomorrow, or be prepared to receive Laughing Kim's fire and fury! You have been warned!

This is the energy I am here for LOL...

[Captain MoMo]

Hello Momo,

I used 0,5qmm x 50cm cables.

What are these specs in the US? 22WG heavy duty wires?

[Firebird]

Firebird, awesome testing. I think it shows a lot. I'm wondering again and guessing that if flaps were lowered and stalled or close to it, that same voltage drop could be assumed to be applied to the elevators. (The voltage is affected across the whole system) Also, if the elevators are taking on their own load, the total voltage drop would be even greater?

Telemetry - test 7 Bluebox / Wings connected



Test 7 shows the voltage at the upgraded stock elevator servo during the condition both elevator servos stalled in combination with both flap servos stalled. It is an attempt to simulate the scenario „mig diving“ at high speed with flaps extended while applying full elevator up command to stop the dive.

Setup:


Jeti Mui150 telemetry sensor soldered into the servo power line directly in front of one upgraded stock servo. Both upgraded stock servos mounted into a benche vise - forcing them to stall when elevator input is applied. Both elevator servos connected via the stock elevator servo cables - connected to the related elevator outputs of the bluebox. Both wings connected via the stock wing connection cables into the bluebox. Bluebox connected via the bluebox elevator and flap patch cables into the related channels of my jeti rex12 receiver. Stock BEC directly powering the receiver. No other equipment connected.


Find below the voltage at the servo with the related voltage at the receiver:

1. System powered, all servos in idle (no movement / no force): Voltage at the receiver 4,97 volt / voltage at the elevator servo 4.8volt
2. Flaps extended, both flap servos forced to stall by hand. Additionally full elevator up command forcing both elevator servos to stall same time in the bench vise. Voltage at the receiver 4,80volt / voltage at the elevator servo 4,0volt

[Firebird]

What are these specs in the US? 22WG heavy duty wires?

0,5qmm should be 20AWG in US

[GliderGuy]

Firebird - The missing link is the telemetry data from actual flying. Granted your flights will be with the hacker servos, but the excellent data you have collected should allow for a correlation to stock when flight servo current telemetry data is reviewed.

When do you anticipate being able to fly to gather flight data/load information?

Test #7 clearly shows violation of the published minimum ROC servo voltage spec. Proper Servo operation lower than 4.8 V is an unknown and might vary from servo to servo. Operation outside mfg ROC of ANY products we use on a day to day basis is risky.

It would be a fun experiment to put some lightly loaded servos on a tester and start reducing the servo power voltage (assume stable/same drive signal strength) to find out when they stop functioning. Not that this would be applicable across all servos...It WOULD NOT! Also, importantly....finding they operate fine below 4.8V would not be justification for operation at less than 4.8V!!!!! Just an interesting data set.

-GG

[kallend]

Both the F-14 and Sukhoi 35 have large FFS with long skinny leads to the servos. I don't recall hearing of a rash of elevator authority fails with either of these.

[Evan D]

So does my old V1 F/A-18E with a 2mm axle in a tiny plastic square on the fuselage to hold it and super thin push rods with really wimpy 9g servos. Maybe that's the fix?

[nuts-n-volts]

I want to thank Firebird for all of that testing. Right on! It reaffirms much of what I've suspected for a while. I also asked Motion how much can you up the voltage in their system. Not much! Here's their 2 answers. The first is about the retracts specifically:

"Hi Greg, Thanks for contacting us on your question. They are 4.8-5 volts. But the blue box has the sequencer built in it for the gear doors to function properly. I have not had any issues with the PCB yet on it."

And then this:

"Let me answer it this way. Anything close to 6 volts will damage the retracts, blue box and servos for Freewing products."

I find this sorta disparaging as most all servos these days are rated 4.8-6.0v. Why have a limiting factor such as retracts or an MCB-e bring that value down? Especially when we're running 11 servos, 3 retracts, and lights? Pretty heavy load just with all that. Now add in long skinny wires and a Y-conn on the most important servo pair while going thru another 2 connections (box/lead). I don't particularly mind fixing/upgrading a new plane. Tough to do when there are these sorts of limitations.

What I can do is the same as most of you are doing because of this thread. And I appreciate everyone's inputs on this jet as that is what I come here for. So, pushrods, ball links, leads (shorter, bigger), upgraded servos, alignment, bypass MCB, and yeah, maybe even figure out how to run 2 different voltages.