Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[RudyD54]

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.

Radio: Spektrum IX20

Receiver/gyro:
Spektrum AR637T behind rear battery bay with antennas pointing outwards towards the wings and a Spektrum 4651T remote receiver attached via a 24 inch extension and sitting in the front battery bay. One antenna pointing forward, and another pointing vertically. With this setup I’ve got full diversity in all three planes and didn’t drop a single frame while doing the reduced power range test.

Batteries: Liperior 6S 5000mah 45c mounted rear and middle

Elevators:
Upgraded Freewing servos attached through blue box. Stock pushrods swapped out for Hangar-9 4.5” 4-40 titanium turnbuckles (HAN3556), Dubro Heavy Duty Ball Links, and Dubro Safety Lock Kwik-Links (HIGHLY RECOMMENDED!!)

Final CG: ~10mm behind factory CG marks

Experiences may vary but the following was mine:

Maiden:
Timer set to 3 minutes and I used the book throws and decided on 40% expo for the high rates as that’s what I’m using for my F-22 but that was a huge mistake. She does not like high expo rates. Everything was incredibly slow to respond and numb. This and the fact that I had the CG a little too far back made for a very scary flight. I used half flaps at takeoff and after a long rollout (spongy wet grass) the jet took off like a rocket at a 45 degree angle and required a constant pushing down of the nose to maintain forward flight. It kept pulling into a high alpha position on its own and I felt like I had very little elevator authority. After cruising around at around 75% throttle while trying to figure out why it felt so off, I realized I still had the flaps down. Oops. Flaps went up and suddenly boom. Elevator authority was there and everything was so much better. The tail was still dropping so I brought her in for a landing and she basically flared herself due to the rearward cg. Came down with plenty of voltage left in the batteries and flight one was in the books.

Flight 2:
I reduced expo on aileron and elevator to 30%, increased the timer to 3:30, and using my incredibly accurate patent pending CG machine (index fingers 😆) determined my CG was about 20-25mm back from the stock CG point. Oops number 2. I moved the middle battery forward a bit and the CG was now about 15mm behind the CG marks. Second takeoff was a bit better, although still a little steeper than I liked. The wet grass and the still excessive expo wasn’t making it easy to get off smoothly as it would just leap into the air. Gear up, flaps up, cruised between 50-60% throttle and re-trimmed the elevator a couple of clicks. Even at 50% throttle this plane just moves. It seems to cut through the air really nicely. After a few passes I lowered the gear, dropped half flaps, and came around for a landing. Came in a little hot, but made it down in one piece.

Flight 3:
I still noticed the tail wanting to drop a bit in turns during flight 2 so I moved the middle battery as far forward as I could (where it was butting up against the bottom of the canopy) and this put the CG somewhere around 5-10mm behind the factory CG marks. I also reduced the expo on the elevator to 25% and extended the timer to 4:00. Much better. I pulled a few loops and even got a flip out of it. Coming out of the flip I ended up in a falling leaf which I was able to get out of easily knowing what others have experienced. Chop throttle, nose down to pick up some speed, and add throttle back. Easy as long as you’ve got enough altitude. I decided to try and see what happens with the flaps at higher speeds and I can confirm what a couple of others have stated. There is a pretty significant reduction in elevator authority so I would definitely recommend you not forget to retract them once you’ve taken off. I’m not saying this is the cause for all the accidents we’ve seen, but I could definitely see it being one of multiple compounding factors. After a few more passes, I dropped the landing gear, half flaps, and attempted to land. Man this thing just glides. Came in a little hot again, but better than the last.

Flight 4:
Dropped elevator expo to 20%. Left ailerons and rudder at 30% which I still may lower but we shall see after a few more flights. Upped timer to 4:30 and taxied out to the runway. I did notice something interesting this time as the grass had started drying up and became more spongy and that’s that the jet likes to slide around like a drift car. It was so bad I actually brought it back in thinking something was loose, but Hugh and I could find nothing wrong so back to the runway. Until this point, I hadn’t turned on my gyro at all (frankly this jet is very stable without it) so I decided this would be the flight to set the gains. Half flaps again, and this takeoff was PERFECT. By this flight my nerves had finally calmed down and my hands had stopped shaking so I upped the gains via the knob to the default AR637T max which is 40/50/60 Yaw/Pitch/Roll and flew her around pretty hard, a couple lower passes across the runway at full throttle, a few more loops, flips, and a snap or two. This may be my new favorite jet. It’s so incredibly locked in, looks beautiful, and sounds incredible in the air. I think I still need to up the roll rate but I can’t wait to see how this will perform with the thrust vectoring. I had a blast. Once my timer was up I dropped the gear, half flaps, and lined up for landing. This time I was able to get the speed and attitude perfect and touched down exactly where I needed to, but didn’t pay attention to my heading and ended up in the thicker grass/weeds off the side of the runway which is known for tearing the nose gear out of lesser jets (my E-Flight F-16 included) but amazingly zero damage. The gear on this jet are incredibly tough and the weeds made for a very effective braking zone 😆

All in all it was a very successful day and I’m very happy with the MiG. I can’t wait to get it out again and explore some more of the flight envelope.

[Borat]

That’s interesting. Your experience with the flaps dovetails with what I had stated previously. What we need is videographic evidence of what is happening with elevator deflection during high speed, flap deployed configuration. It’ll be a challenge and if I make it to the field this weekend I’ll try it. If we can see elevators holding their position appropriately and proportionate to elevator input then it would suggest that there maybe aerodynamic issues involved at higher speeds and not just servos crapping out

[Doug Fales]

What I don’t understand is why some are experiencing elevator issues and as far as I know many planes are working fine? I would agree it’s is required to upgrade the servos to D85, better linkage and thicker rods and bypass the blue box. I mean other than that what the heck else can you do. I want to pull the trigger on this plane but all this talk is very concerning. Do I need to avoid 30-45 degree dives also? That’s my go to move on all my planes. Lol

[Evan D]

I typed a long thing out about the probability of having an issue and other things like what happens if someone gets hurt by one and decided to just delete it.

I just hope owners read the forums.

[Hugh Wiedman]

Radio: Spektrum IX20

Receiver/gyro:
Spektrum AR637T behind rear battery bay with antennas pointing outwards towards the wings and a Spektrum 4651T remote receiver attached via a 24 inch extension and sitting in the front battery bay. One antenna pointing forward, and another pointing vertically. With this setup I’ve got full diversity in all three planes and didn’t drop a single frame while doing the reduced power range test.

Batteries: Liperior 6S 5000mah 45c mounted rear and middle

Elevators:
Upgraded Freewing servos attached through blue box. Stock pushrods swapped out for Hangar-9 4.5” 4-40 titanium turnbuckles (HAN3556), Dubro Heavy Duty Ball Links, and Dubro Safety Lock Kwik-Links (HIGHLY RECOMMENDED!!)

Final CG: ~10mm behind factory CG marks

Experiences may vary but the following was mine:

Maiden:
Timer set to 3 minutes and I used the book throws and decided on 40% expo for the high rates as that’s what I’m using for my F-22 but that was a huge mistake. She does not like high expo rates. Everything was incredibly slow to respond and numb. This and the fact that I had the CG a little too far back made for a very scary flight. I used half flaps at takeoff and after a long rollout (spongy wet grass) the jet took off like a rocket at a 45 degree angle and required a constant pushing down of the nose to maintain forward flight. It kept pulling into a high alpha position on its own and I felt like I had very little elevator authority. After cruising around at around 75% throttle while trying to figure out why it felt so off, I realized I still had the flaps down. Oops. Flaps went up and suddenly boom. Elevator authority was there and everything was so much better. The tail was still dropping so I brought her in for a landing and she basically flared herself due to the rearward cg. Came down with plenty of voltage left in the batteries and flight one was in the books.

Flight 2:
I reduced expo on aileron and elevator to 30%, increased the timer to 3:30, and using my incredibly accurate patent pending CG machine (index fingers 😆) determined my CG was about 20-25mm back from the stock CG point. Oops number 2. I moved the middle battery forward a bit and the CG was now about 15mm behind the CG marks. Second takeoff was a bit better, although still a little steeper than I liked. The wet grass and the still excessive expo wasn’t making it easy to get off smoothly as it would just leap into the air. Gear up, flaps up, cruised between 50-60% throttle and re-trimmed the elevator a couple of clicks. Even at 50% throttle this plane just moves. It seems to cut through the air really nicely. After a few passes I lowered the gear, dropped half flaps, and came around for a landing. Came in a little hot, but made it down in one piece.

Flight 3:
I still noticed the tail wanting to drop a bit in turns during flight 2 so I moved the middle battery as far forward as I could (where it was butting up against the bottom of the canopy) and this put the CG somewhere around 5-10mm behind the factory CG marks. I also reduced the expo on the elevator to 25% and extended the timer to 4:00. Much better. I pulled a few loops and even got a flip out of it. Coming out of the flip I ended up in a falling leaf which I was able to get out of easily knowing what others have experienced. Chop throttle, nose down to pick up some speed, and add throttle back. Easy as long as you’ve got enough altitude. I decided to try and see what happens with the flaps at higher speeds and I can confirm what a couple of others have stated. There is a pretty significant reduction in elevator authority so I would definitely recommend you not forget to retract them once you’ve taken off. I’m not saying this is the cause for all the accidents we’ve seen, but I could definitely see it being one of multiple compounding factors. After a few more passes, I dropped the landing gear, half flaps, and attempted to land. Man this thing just glides. Came in a little hot again, but better than the last.

Flight 4:
Dropped elevator expo to 20%. Left ailerons and rudder at 30% which I still may lower but we shall see after a few more flights. Upped timer to 4:30 and taxied out to the runway. I did notice something interesting this time as the grass had started drying up and became more spongy and that’s that the jet likes to slide around like a drift car. It was so bad I actually brought it back in thinking something was loose, but Hugh and I could find nothing wrong so back to the runway. Until this point, I hadn’t turned on my gyro at all (frankly this jet is very stable without it) so I decided this would be the flight to set the gains. Half flaps again, and this takeoff was PERFECT. By this flight my nerves had finally calmed down and my hands had stopped shaking so I upped the gains via the knob to the default AR637T max which is 40/50/60 Yaw/Pitch/Roll and flew her around pretty hard, a couple lower passes across the runway at full throttle, a few more loops, flips, and a snap or two. This may be my new favorite jet. It’s so incredibly locked in, looks beautiful, and sounds incredible in the air. I think I still need to up the roll rate but I can’t wait to see how this will perform with the thrust vectoring. I had a blast. Once my timer was up I dropped the gear, half flaps, and lined up for landing. This time I was able to get the speed and attitude perfect and touched down exactly where I needed to, but didn’t pay attention to my heading and ended up in the thicker grass/weeds off the side of the runway which is known for tearing the nose gear out of lesser jets (my E-Flight F-16 included) but amazingly zero damage. The gear on this jet are incredibly tough and the weeds made for a very effective braking zone 😆

All in all it was a very successful day and I’m very happy with the MiG. I can’t wait to get it out again and explore some more of the flight envelope.

Great Flight RudyD54, this jet flies awesome, or maybe it's the pilot! Nah, no way! Attached is the video I took of his flights (didn't include the maiden though cause all I got was the take-off and then shut it down cause I got nervous and couldn't track it-but not Rudy), sorry it's a little longer than I usually do, but just couldn't take my eyes off of it and I wish I could have zoomed in a few times but I'm blind as a bat, had enough trouble just keeping it in the frame of my cell phone. Definitely tons of extra power, unlike the SU-30 pig. Oddly enough, with almost 500 members, this is the first Mig-29 at our field (and definitely not the last cause now I gotta have one also and I know who is going to set it up). Happy Halloween to everyone and a big congratulations to Rudy!

[GliderGuy]

What I don’t understand is why some are experiencing elevator issues and as far as I know many planes are working fine? I would agree it’s is required to upgrade the servos to D85, better linkage and thicker rods and bypass the blue box. I mean other than that what the heck else can you do. I want to pull the trigger on this plane but all this talk is very concerning. Do I need to avoid 30-45 degree dives also? That’s my go to move on all my planes. Lol

Doug, The best thing you can do is study this forum....especially the posts within the last week or two as the group begins to get it “figured out”. Still more work, but getting closer.

It seems to be a good practice to avoid full or 1/2 flaps in combination with high speed flying (above 1/2 throttle) and avoid a flying style that’ll put undue stress on the elevator servos until you upgrade to bigger wire feeding them. Implement any other suggestions presented in this forum that you wish.

Pay special attention to your radio installation, too. Follow best practices.

Review the posts on how to recover from the falling leaf deep stall and those which have successfully recovered from the “no elevator” response situation.

Once you are satisfied with your upgrades...have fun with it. It’s a hoot to fly and a crowd pleaser!

-GG

[HaroldAnderson]

Folks,

I received the Mig29 little less than 3 weeks ago. I’ve flown it at least 15 times. I love this plane and I think it flies great. But word of caution. I tested a hypothesis today out of concern that you could inadvertently crash this plane. I know there has been issues with this plane regarding elevator control and there maybe different issues involved. My hypothesis is that this plane may lose control with flaps deployed and going to full throttle. This is not something that’s routinely done but could happen if you’re not aware that your flaps are deployed. Every time I tried that today, the result was the same. Of course I tried this at high altitude. Flap deployed, nose of the plane pointed down at around 20-30 degrees, full throttle and the plane pitched down further with no elevator control. Only way to bail out is to raise the flap, lower throttle-to give your self time before you hit the ground- and you will regain elevator control.

All of you who still have this plane can try this maneuver to prove it but please do it from high altitude. If I can capture on video I would be happy to post. But for now, be very careful with going to full throttle with flaps deployed. No issue with landing this plane with throttle management during landing using flaps. I suspect there maybe turbulent airflow over the elevators at higher speeds with flaps deployed. But I don’t know that for sure

I have noticed the same thing and have posted about it but everyone wants to find an 'electronic gremlin'. I have not tried reflexing the flaps. The Mig has some unusual characteristics. My radio is programmed to announce 'FLAPS DEPLOYED' at any throttle setting above 50% on all my planes. I think it is especially important on this plane! If a radio is not capable of this you could add a mix that would start to pull flaps up at throttle settings above 50% to be safe. I run my CG 8-10mm back but think this characteristic is probably more pronounced with the stock CG. I have upgraded servos on the inside hole and reinforced pushrods.

This plane flies awesome but I don't do any diving high speed passes with it like on some of my other jets, especially the under 10 feet passes. It just doesn't need to be that low to be impressive.... The sound and look as it is climbing out with afterburners glowing is just too cool. Flight number 29 today was non-stop touch and goes, climbing out with the exhaust pointed toward the spectators for more afterburner and sound effect fun...

[Doug Fales]

Doug, The best thing you can do is study this forum....especially the posts within the last week or two as the group begins to get it “figured out”. Still more work, but getting closer.

It seems to be a good practice to avoid full or 1/2 flaps in combination with high speed flying (above 1/2 throttle) and avoid a flying style that’ll put undue stress on the elevator servos until you upgrade to bigger wire feeding them. Implement any other suggestions presented in this forum that you wish.

Pay special attention to your radio installation, too. Follow best practices.

Review the posts on how to recover from the falling leaf deep stall and those which have successfully recovered from the “no elevator” response situation.

Once you are satisfied with your upgrades...have fun with it. It’s a hoot to fly and a crowd pleaser!

-GG

[Doug Fales]

Yes thank you. I made note of the flight characteristics and what to avoid. I have ordered all of the elevator upgrade parts. Just trying to work up the nerve the purchase the plane. Lol. I think with care and preparation all should be fine.

[Evan D]

Some numbers about the servos. The stock 17g servos put out about 37.5 in-oz. The upgraded FW 24g are about 47 in-oz. An increase of 25% of force to the stab.

Moving the pushrod in from the recommended middle hole (13mm from center) to the inner hole (9mm from center) on the FW servos is a 46% increase in force to the stab.

[kallend]

Some numbers about the servos. The stock 17g servos put out about 37.5 in-oz. The upgraded FW 24g are about 47 in-oz. An increase of 25% of force to the stab.

Moving the pushrod in from the recommended middle hole (13mm from center) to the inner hole (9mm from center) on the FW servos is a 46% increase in force to the stab.

I wonder at what compressive load the pushrods succumb to Euler buckling, especially given that the load is offset at the servo end.

[themudduck]

So many posts... lots of good info. Is the consensus that the elevator servos can stall (both at once) due to a voltage drop? That could explain why they both stop working at the same time.
.
Let me mention that when it happened to me, I didn't have the flaps down and I was just cruising in a slight dive at low speed.... so no stress (aerodynamic or electronic).
But, it was towards the end of my flight, about 30 seconds before landing!

Let me ask the group this: could it be that the BEC is supplying a lower voltage when the flight batteries are low? In my case the flight pack was probably down to around 3.8 per cell - and its quite likely that the voltage could have dropped a bit more (the voltage will recover a bit after landing). I don't have telemetry, I'm just sayin'. I know that the BEC is connected to the entire battery (not one cell) but maybe a voltage drop can affect its performance?
.
I am thinking that perhaps we could try using a separate battery pack to power the BEC in the hope of providing a more steady voltage. I have noticed that when testing the two flight packs after each flight, one battery is usually drawn down more than the other. (the one that's running the BEC) For example I'll come down with 3.84/cell on one pack and 3.79/cell on the other. I'm curious what you guys think about this.
.
I'll also upgrade the elevator "Y" cable to a thicker one.... but what do you think about the BEC idea?

[xviper]

Let me ask the group this: could it be that the BEC is supplying a lower voltage when the flight batteries are low? In my case the flight pack was probably down to around 3.8 per cell - and its quite likely that the voltage could have dropped a bit more (the voltage will recover a bit after landing). I don't have telemetry, I'm just sayin'. I know that the BEC is connected to the entire battery (not one cell) but maybe a voltage drop can affect its performance?
.
I am thinking that perhaps we could try using a separate battery pack to power the BEC in the hope of providing a more steady voltage. I have noticed that when testing the two flight packs after each flight, one battery is usually drawn down more than the other. (the one that's running the BEC) For example I'll come down with 3.84/cell on one pack and 3.79/cell on the other. I'm curious what you guys think about this.
.
I'll also upgrade the elevator "Y" cable to a thicker one.... but what do you think about the BEC idea?

I can't see that happening. Even if the battery was down to 3.5v/cell, it's still putting out 21V to the BEC. It still needs to scale that down to around 5V to send to the RX. The main battery would have to get down to less than 1v/cell before it can't give the BEC what it needs.

[Airguardian]

I mean other than that what the heck else can you do.

Get better wires (thicker gauge) and power the UBEC with a separate rx Li-Po pack ;)

I am thinking that perhaps we could try using a separate battery pack to power the BEC in the hope of providing a more steady voltage. I have noticed that when testing the two flight packs after each flight, one battery is usually drawn down more than the other. (the one that's running the BEC) For example I'll come down with 3.84/cell on one pack and 3.79/cell on the other. I'm curious what you guys think about this.

I think so and have said that much already, of course disagreeing with xviper.

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

That's quite damning. I think we are finally getting close to the root issue here.

Telemetry - test 6 Bluebox

Test 6 is showing the provided force (in gram) that both upgrade stock servos provide together, related to the voltage at the servos. Servoarms pressing against a kitchen scale is simulating aerodynamic pressure on the elevator in flight.

[...]

volt at servo 4,2/ volt at receiver 4,90 / force together 3689gram / force single servo 1844,5gram (maximum)

Are you doing these and previous tests with servos connected directly to BB/Receiver or using the stock wire extensions?

If you plugged them directly, then I think it'd be great to see what happens when you add the long-thin stock wire extensions ;)

Thank you very much for the effort! :)

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.

But they (Su-35 at least) have the pivot point much more aft on a stab with less sweep angle and the airframes are like 2kg to 3kg lighter.

Meaning; the force on the MiG-29 stab hinges will be much higher, from pivot hinge position, stab size and geometry and increased loads from stab trim with a jet that flies considerably faster and heavier on average.

[GliderGuy]

Airguardian - please re-read Firebird’s posts. He states the setup conditions for each test clearly.

He stated he would be on a trip/flights...so he may not respond for a bit. Stepping in for him if this is the case.

What we need now is the telemetry data from his actual flights (to come). We should be able to tie this back to his previously taken data albeit telemetry data will be from the hacker servos which draw more current. Correlation should still be possible.

I agree....we may be getting close! Seeing voltages going below the minimum spec’d 4.8V for the servos is not a good thing. Definitely indicates that bigger wire gauge is needed for worst case conditions.

Aside - I watched some of your YouTube videos. Nice flying, man!

-GG

[kallend]

But they (Su-35 at least) have the pivot point much more aft on a stab with less sweep angle and the airframes are like 2kg to 3kg lighter.

Meaning; the force on the MiG-29 stab hinges will be much higher, from pivot hinge position, stab size and geometry and increased loads from stab trim with a jet that flies considerably faster and heavier on average.

Ah, an AIRFRAME issue.

[kallend]

Airguardian - please re-read Firebird’s posts. He states the setup conditions for each test clearly.

He stated he would be on a trip/flights...so he may not respond for a bit. Stepping in for him if this is the case.

What we need now is the telemetry data from his actual flights (to come). We should be able to tie this back to his previously taken data albeit telemetry data will be from the hacker servos which draw more current. Correlation should still be possible.

I agree....we may be getting close! Seeing voltages going below the minimum spec’d 4.8V for the servos is not a good thing. Definitely indicates that bigger wire gauge is needed for worst case conditions.

Aside - I watched some of your YouTube videos. Nice flying, man!

-GG

A plane doesn't lose elevator authority on account of a voltage drop if the servos are still exerting a large enough force at their output. I don't recall anything in firebird's data suggesting that the servos quit working except in one case when one servo reversed when stalled. And that wasn't correlated with the voltage drop but with the stalled condition.

Getting overly fixated on a voltage drop is not what is needed. How does the servo behavior change under load is what is relevant, and does that depend on the gauge of the leads?

Also is there any buckling of the pushrods, flexing of the pivots or pivot mounts, control horns, and other parts of the structure when under load.

[Doug Fales]

Some numbers about the servos. The stock 17g servos put out about 37.5 in-oz. The upgraded FW 24g are about 47 in-oz. An increase of 25% of force to the stab.

Moving the pushrod in from the recommended middle hole (13mm from center) to the inner hole (9mm from center) on the FW servos is a 46% increase in force to the stab.

[Doug Fales]

Those numbers for the free wing servos would that be at 4 V or 6 V please?

[Mr.Stang]

Hello all

i have here a Pic from the Elevator
they show the right position with the cfk Rod
A Friend of my have a little Program for calculating the optimal Elevator Axle configuration
Also check please the Force you need for Blocking the Servo on the rear end of the Elevator!
you will see this only a few Grams!

Other Pics show they Airstream the block they Elevator with the wrong Axleposition

After research all Treads with Migproblems its the only Reason why all they Migs crashed
All Mods inklude the Turbinevariants have allways the same Prob

Hope this helps for the Investigation
Orbhave anybody conections to Freewing direct.

Thanks Fred