Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[mshagg]

Yeah 5+ minutes on 6000s at half throttle sounds reasonable to me. This is the beauty of having two 6000mah power sources onboard - both in terms of battery capacity and the amount of thrust being generated at half throttle with two edfs.

Just check the cell voltages, only way to be sure. And gradually increase flight times. I have telemetry providing live callouts and bring her down at 3.6v/cell which comes to rest at perfect storage charge.

Honestly between this and the f14 I'm not sure I'll buy any more 6S single 90mm jets.

[RuthR720]

Great job with the MiG MRC! I flew it twice today with the stock elevator servos with no issue. I’ll push it harder once the servo upgrades arrive. I really appreciate the call from Alpha and the email. The new main wing screw anti-drop design is excellent. On future aircraft would it be feasible to swap the pylon tabs on the wing with the slots on the pylons? I prefer flying without ordnance and just cover the slots with Scotch tape to reduce drag. All those tabs do is slow me down.

https://youtu.be/RKJ1w-PITIM

https://youtu.be/wrpKWGZbma0

[janmb]

Great job with the MiG MRC! I flew it twice today with the stock elevator servos with no issue. I’ll push it harder once the servo upgrades arrive. I really appreciate the call from Alpha and the email. The new main wing screw anti-drop design is excellent. On future aircraft would it be feasible to swap the pylon tabs on the wing with the slots on the pylons? I prefer flying without ordnance and just cover the slots with Scotch tape to reduce drag. All those tabs do is slow me down.

https://youtu.be/RKJ1w-PITIM

https://youtu.be/wrpKWGZbma0

The actual impact of these tiny tabs are next to nothing. It provides exactly zero practical difference in flight time.

Swapping genders is problematic since it would break compatibility with all previous attachments people would like to reuse

[mick8488]

The MiG is ready for maiden flight, I ended up replacing the elevator servos with some Hitec 5085’. Moved the blue box under the rear battery tray, tailerons, Castle BEC, and gear door mode done. Had to carve some foam from the canopy to get the correct CG using RT 5500 45c. Gave the armament some color and I’m glad I did.

How did the Hitec servos fit? Were they drop in? I'm considering getting some for my MiG when it shows next week, even though I should be sent the upgraded ones. I wonder if those Hitec's will fit the aileron mounts as well.

[mshagg]

D85MG are a direct fit - 5 minute job.

[Texassoldier87]

Im trying to figure this whole elevator servo failure thing out. All of the videos I've seen, the planes are diving in with zero elevator control. What are the odds of both servos failing at the exact same time on every one? I just find this very strange.

[Bushong572]

I haven't seen a RTF weight so I thought I would post mine: 12.8 lbs with RT 5500 45C/ 2 coats of Minwax (no ordinance). Really light for the size.
I didn't like the elevator linkage so I changed it.
4-40 all thread
carbon sleeve
Sullivan clevises
Dubro ball links

[Bushong572]

I still don't like the angle of the linkage, but I will stick with the recommended middle hole.
I applaud Motion for their quick action and sending us new servos.

[Gringotuerto]

Im trying to figure this whole elevator servo failure thing out. All of the videos I've seen, the planes are diving in with zero elevator control. What are the odds of both servos failing at the exact same time on every one? I just find this very strange.

It isn't the servo failing; in all cases where photos are available, the pushrod was connected to the outermost (incorrect) hole on the servo arm. So the torque on the servo was increased. Since the servo can produce 2.5kg-cm of torque, once you go beyond that it just can't move the elevator anymore. When both tailplanes are configured the same, and in the same position, and moving the same speed, they are both exerting about the same force on the servos. So if the left one is loaded with >2.5kg-cm, so is the right one. I don't find it strange at all that two of the same servos bind when given the same over-spec load.

[Mavernick*]

gooniac33 check your messages please and let me know. Thanks.

[JohnVH]

Check out my Mig29 Maiden!

[nuts-n-volts]

I've said it before, and I'll stick to it. These crashes have everything to do with being way too nose heavy and most having the linkage in the outer hole on the servo (not enough torque). And with the elevator servos being less than up for that task. These servos are over extended if not set up correctly. That's exactly why Motion/Freewing just put out new upgraded servos to all who bought/buy this plane.

The reason I'm sure these crashes were caused mostly by being nose heavy are two things. First, the 3 battery bays are a bit confusing. If you read the instructions, Freewing recommends to put the forward battery on the hump, not in the forward bay. If you're not reading, it would be very easy to miss, and that big forward bay looks pretty inviting. Second, all the crash vids show pretty much the same thing. The pilot has control - roll is there, but pitch is sluggish in up with nary any down used. Too much roll ends up with a substantial dive that, as speeds builds, cannot be pulled out of. The servos with incorrect linkage are over-tested.

Use the new replacement servos just shipped with correct linkage hook-up and I'm sure you'll be fine. If you still feel that they are inadequate, replace them with even better servos, as some have already done. I will go this route as well and then move the new replacement servos to the flaps. Beefing up the elevator linkage is something I always do on these foam jets. They are pushing the loads on the equipment and we/they must recognize these issues.

[Reaper911]

Yeah 5+ minutes on 6000s at half throttle sounds reasonable to me. This is the beauty of having two 6000mah power sources onboard - both in terms of battery capacity and the amount of thrust being generated at half throttle with two edfs.

Just check the cell voltages, only way to be sure. And gradually increase flight times. I have telemetry providing live callouts and bring her down at 3.6v/cell which comes to rest at perfect storage charge.

Honestly between this and the f14 I'm not sure I'll buy any more 6S single 90mm jets.

I can get about 3:30 of mixed flying on Admiral Pro 6s 6000mah with 23% in the tank and 3.77v per cell. 5 min and I would be subterranean

[1horse59]

Im trying to figure this whole elevator servo failure thing out. All of the videos I've seen, the planes are diving in with zero elevator control. What are the odds of both servos failing at the exact same time on every one? I just find this very strange.

I can only assume that when using the most outer hole, and given down elevator, the forward edge gets stuck to the side of the rudder wall

[Reaper911]

Check out my Mig29 Maiden!

Nice maiden John but you must have puckered just before rotation. Thought you were gonna clean the gear off on the curb

[JohnVH]

Nice maiden John but you must have puckered just before rotation. Thought you were gonna clean the gear off on the curb

Closer than I like to have them, I was standing off to the side, so it didnt seem quite that close, but it all worked out great. :)

[Evan D]

Exactly...

I've said it before, and I'll stick to it. These crashes have everything to do with being way too nose heavy and most having the linkage in the outer hole on the servo (not enough torque). And with the elevator servos being less than up for that task. These servos are over extended if not set up correctly. That's exactly why Motion/Freewing just put out new upgraded servos to all who bought/buy this plane.

The reason I'm sure these crashes were caused mostly by being nose heavy are two things. First, the 3 battery bays are a bit confusing. If you read the instructions, Freewing recommends to put the forward battery on the hump, not in the forward bay. If you're not reading, it would be very easy to miss, and that big forward bay looks pretty inviting. Second, all the crash vids show pretty much the same thing. The pilot has control - roll is there, but pitch is sluggish in up with nary any down used. Too much roll ends up with a substantial dive that, as speeds builds, cannot be pulled out of. The servos with incorrect linkage are over-tested.

Use the new replacement servos just shipped with correct linkage hook-up and I'm sure you'll be fine. If you still feel that they are inadequate, replace them with even better servos, as some have already done. I will go this route as well and then move the new replacement servos to the flaps. Beefing up the elevator linkage is something I always do on these foam jets. They are pushing the loads on the equipment and we/they must recognize these issues.

Umm, no. There's no way anyone would give that amount of down elevator....

I can only assume that when using the most outer hole, and given down elevator, the forward edge gets stuck to the side of the rudder wall

[Reaper911]

Closer than I like to have them, I was standing off to the side, so it didnt seem quite that close, but it all worked out great. :)

[Lcacing]

Today was maiden day for my MiG, video coming soon, did 3 flights in less than perfect conditions, cross wind @ 15mph.
First thing to mention is the CG, I decided to go further back than recommended, about one finger width back from the marks. Checked the CG in the air with gear up and down, inverted flight required a fair amount of down elevator.
Also did a stall test, full up elevator until almost zero forward speed, finally the nose just drop straight down, kept the elevator at full up and added some throttle and it kept flying. Loops can be tight, it almost loop at length of the fuselage.
The MiG is set up with tailerons and ailerons and slow rolls looked great. Landing were a bit tough because of the cross wind but the MiG handled it like a champ.
For the next flights I will be moving the CG further back.

[JohnVH]

wow, one finger back? I may have to experiment with some CG play