Official Freewing MiG-29 Fulcrum Twin 80mm Thread

[crxmanpat]

Great fun flying with (right to left) corsair nut, JLambCWU, JLink and myself at the Remote Possibilities field in St George, UT this past week. Probably 100 flights between the 4 of us and only one mishap (wind picked plane back up after landing and plopped it down hard, messing up the LG). I will have some videos to post soon.

[RCPLANEFANATIC]

My MiG-29 crashed on the 12th flight on the airframe. I took off with the intention of doing two fast passes and then use the rest of the flight for photo passes. I did the fast passes and one flyby at full flaps. I circled back and approached the runway from the north with full flaps and gear extended. After climbing out of a slow, dirty pass from left to right, I flipped my gear and flaps switches up and began a shallow left turn back towards the field. As I centered my right control stick, the plane pitched up to 20 degrees, did an uncommanded right roll to about 30 degrees past neutral and did not respond to the full left aileron I was inputting. The pitch change meant that the plane lost airspeed and entered a high alpha flight attitude. After a second or so of holding left aileron and slight down elevator along with full power in a futile attempt to increase airspeed, I centered control on the ailerons thinking that one of the wing control surfaces was stuck. At that point the plane did a hard right turn and dove for the ground from 100 feet. I cut power and pulled up elevator. When I recovered the plane, the gear and flaps were still down. The battery had ejected, so I wasn’t able to test the controls as they were in flight. After plugging in the battery all the surfaces operated as they should. The only damaged components are the left main retract, nose retract, and nose cone due to a conveniently located bush. The rest of the damage is mainly cosmetic, though I am slightly worried about the compression and small foam fractures throughout the airframe.
It was not a radio lockout, I have an AR8010t and two satellites properly oriented in the plane and as soon as I felt something went wrong I made sure that I was not pointing the radio directly at the plane. I did a full range test before my maiden and had no glitches.

[crxmanpat]

Man, sorry to hear that. Unscrew the wiring connector from the left wing root and pull out all the servo wires. Isolate the left flap lead and test it out. Almost sounds like the left flap did not go back up when you raised flaps and gear.

Do you have your flap servos slowed at all?

[RCPLANEFANATIC]

https://youtu.be/tBn4iuXrhkg

Here’s the video to accompany my previous post- sorry for the potato quality, we were using the good camera for photos.

[RCPLANEFANATIC]

Man, sorry to hear that. Unscrew the wiring connector from the left wing root and pull out all the servo wires. Isolate the left flap lead and test it out. Almost sounds like the left flap did not go back up when you raised flaps and gear.

Do you have your flap servos slowed at all?

My flaps are set at 3.0s in my DX9 flap system. I checked the wire harness connections before my maiden, and I’ll check it all again when I get it on the bench.

[T-CAT]

Great fun flying with (right to left) corsair nut, JLambCWU, JLink and myself at the Remote Possibilities field in St George, UT this past week. Probably 100 flights between the 4 of us and only one mishap (wind picked plane back up after landing and plopped it down hard, messing up the LG). I will have some videos to post soon.

Looks like a ton of fun!

[xviper]

I've owned alot of jets with full flying stabs (turbine and EDF). I've never seen one require this much up trim to fly level.....seems very inefficient.
Either the recommended CG is very far forward (which I know it is to some degree) or there is an incidence problem.

Not full flying stabs but ............................ Both my LX A-10 and my current Freewing A-10 had to have a lot of UP trim on the ELE. The LX was at least 5mm and the FW was a bit less than that. I've always wondered about the reasons why this had to be. Have never really found a good answer. Did the factory get the CG wrong? Is there some weirdness in the way the model got scaled down from the real thing? The answer would be quite enlightening.
Oh and same goes for my Dynam B-26 and a couple others that I no longer have.

My MiG-29 crashed on the 12th flight on the airframe. I took off with the intention of doing two fast passes and then use the rest of the flight for photo passes. I did the fast passes and one flyby at full flaps. I circled back and approached the runway from the north with full flaps and gear extended. After climbing out of a slow, dirty pass from left to right, I flipped my gear and flaps switches up and began a shallow left turn back towards the field. As I centered my right control stick, the plane pitched up to 20 degrees, did an uncommanded right roll to about 30 degrees past neutral and did not respond to the full left aileron I was inputting. The pitch change meant that the plane lost airspeed and entered a high alpha flight attitude. After a second or so of holding left aileron and slight down elevator along with full power in a futile attempt to increase airspeed, I centered control on the ailerons thinking that one of the wing control surfaces was stuck. At that point the plane did a hard right turn and dove for the ground from 100 feet. I cut power and pulled up elevator. When I recovered the plane, the gear and flaps were still down. The battery had ejected, so I wasn’t able to test the controls as they were in flight. After plugging in the battery all the surfaces operated as they should. The only damaged components are the left main retract, nose retract, and nose cone due to a conveniently located bush. The rest of the damage is mainly cosmetic, though I am slightly worried about the compression and small foam fractures throughout the airframe.
It was not a radio lockout, I have an AR8010t and two satellites properly oriented in the plane and as soon as I felt something went wrong I made sure that I was not pointing the radio directly at the plane. I did a full range test before my maiden and had no glitches.

Symptoms and diagnosis? Did your plane have the upgraded elevator servos? Was any control surface by-passing the blue box? Where was your RX relative to the battery and power lines. I'm using the same RX as you and have located it in the nose while all the wiring runs along side of the top battery. The rear battery is butted up against the wiring as it runs up to the control box. About to maiden in a couple of days. You got me a little pensive.

[Airguardian]

Judging from that crash, looks like the MiG-29 and the Hornet share a problem with flap servo authority.
Using full flying stabs might had allowed you to fight it out and save the jet, but then again... these jets are 'factory reccommended' to be dumbed down. A lot of pilots may also crash their jets due to bad taileron setup. Personally I think it'd be better to teach pilots to use the full potential of the jet in a safe fashion. Using conventional elevators and ailerons on a jet designed to use tailerons is a waste. That's my personal opinion, feel free to disagree.

Were you running the jet from the supplied BEC out of one of the main Li-Po packs or did you use a separate Rx pack and/or separate custom UBEC? What specs if so?

I've owned alot of jets with full flying stabs (turbine and EDF). I've never seen one require this much up trim to fly level.....seems very inefficient.
Either the recommended CG is very far forward (which I know it is to some degree) or there is an incidence problem.

No need to look further. It's most likely just the usual case of factory recommendation for CG being over-conservative.

If you experiment with more aft CGs and still have issues, then you may consider other factors at play, but first things first! :)

Not full flying stabs but ............................ Both my LX A-10 and my current Freewing A-10 had to have a lot of UP trim on the ELE. The LX was at least 5mm and the FW was a bit less than that. I've always wondered about the reasons why this had to be. Have never really found a good answer. Did the factory get the CG wrong? Is there some weirdness in the way the model got scaled down from the real thing? The answer would be quite enlightening.
Oh and same goes for my Dynam B-26 and a couple others that I no longer have.

We've been talking this for almost the entire length of the thread.

Factory recommendations do not give a 'balanced CG', they give a pretty nose-heavy CG to err on the safety side.
Pilots should be expected to take that as a starting point and adjust to personal preference.

Of course, the reasonable thing to do is to move CG backwards to a more balanced position that does not penalize aircraft performance that much.

In short: Factory CG recommendations are pretty bad. Those of Freewing included.

But since many users act dumb, giving actually 'good CG' recommendations is a liabilty, so there's your 'enlightening reply' :)

[GliderGuy]

Sorry about your loss RCPLANEFANATIC. I hate to see planes go down.

I propose that there is an outside POSSIBILITY that this crash has nothing to do with the location of the CG or that there was no radio/servo/blue box failures.

Let me detail why I state the above. What is presented below could be all wrong, or....it could be correct. In which case, now you are enlightened.

Qualifiers are:

1. What is presented below is a RARE occurence. But, the more flights made....
2. This ugly beast only seems to rear its head when HIGH CURRENT ESCs are involved.
   1. The "fix" is not intended to be used with LOW CURRENT ESC planes...there's no need.
3. Some radios and set-ups are going to be more sensitive.
4. Satellites won't prevent this ugly beast from biting you. They may help, or they may not.
5. The "FIX" is sooooo easy and soooo cheap, why wouldn't you implement it? Lower the odds of the beast biting you!
6. You are free to tell me "Go Pound Sand GliderGuy." But, the undisputable fact is...after implementing the FIX...I have yet to have any radio issue on any plane that has a HIGH CURRENT ESC.
   1. I am a FIRM BELIEVER in what I relate below....my soap box again. 😀
7. I can only relate what i've been taught. I haven't a clue whether my HAM friend is right. And, if he is, how a receiver will behave in these conditions. But...what if the HAM guy is correct?

Watching the video, the MiG behaved very similarly to the F-4 and A-10 that I lost. Basically, the plane goes nuts and based on what the pilot experienced, any number of "possibilities" can be extrapolated (failed servo, failed receiver, blue box, pilot error, etc.). Any of which could be correct, but.....what if they aren't?

Details...As parephrased from what the HAM radio guy told me and as I "understood" what he said:

1. HIGH CURRENT ESCs are known to emit strong common mode RF interference (radio noise)
2. The wires coming from the ESC are excellent RF radiators of this RF noise. The longer the wires...the stronger the RF emissions
3. The RF noise, may (or may not), disrupt the hand shake (binding) between the transmitter and receiver. Do you wanna risk it?
   1. The HAM guy told me (and he could be wrong) that the TX and RX frequency hopping spread spectrum activity is guided by a look-up table. When you bind the RX and TX, the binding process is a synchronizing of the pointers in this look-up table.
      1. The RF noise coming from the ESCs may disrupt the location of the pointer in the RX
4. When the pointer in the RX is disrupted, the receiver looses its mind....so to speak. Good control of the aircraft is lost (there may be the appearance of a response as the RX is trying to regain look-up table synchronization). A crash will occur, if the TX and RX pointers cannot re-synchronize before the crash. Several seconds are required for this process.
5. Add ferrite RF chokes to the wires coming from the ESC (the motor side is not that critical...but the "other" wires are) and place them AS CLOSE TO THE ESC AS POSSIBLE. Any length of wire is an antenna. The closer to the ESC, the better.

What am I referring to? You can get them here.

• From Amazon.... Cedmon 20 Pieces Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3mm/ 5mm/ 7mm/ 9mm/ 13mm Diameter Cable, Black

This is a variety pack, so you have many sizes to pick from. You can also group wires and run them through a single RF choke. I added an additional choke to the throttle wire going from the RX that already has a green ferrite rf choke/donut...overkill, but it can't hurt.

PAYOFF....

1. Restating...I am a firm BELIEVER. I fly a lot, so there is a chance that even a RARE occurence thing will bite me
   1. Since installing these RF chokes in my replacement F-4, and new AL37 and now the MiG, in over a year (for the F-4), I have not had any radio glitch. Nor has the AL37 or MiG given me any hint of a radio glitch (knock on wood).

This could all be hogwash, but are you willing to take that risk for a few dollars and almost no weight addition? If I can push ANY odds of something bad happing farther out in the future, I will take that action. It's not fun to watch a plane crash.

There is plenty of room on either side of the aft battery's aft side to add the RF chokes. Such an easy thing to do for added piece of mind.

For your kind consideration, as always....

-GG

.

[leithalweapon]

Yep, and run the power wires as far away as you can get from the signal wires.

[themudduck]

A friend of mine named Brent Lane, who is a professional photographer (and new RC'r that I am helping) took some pics today during a flight of my Mig. WOW! I am floored at how totally cool these photos are and wanted to share them with you guys. (the first one is from my cellphone)

[RCPLANEFANATIC]

Airguardian: was running the jet completely stock with the upgraded servos from Freewing. As per the instructions, I have the elevator servos plugged directly into the RX and everything else goes through the BB. The only modification I have done is my own centerburners which are running off my other flight battery.
Gliderguy: I’ll look into those ferrite chokes, I really don’t want this to happen again.

[xviper]

GliderGuy .................... These "chokes" .................. Are they giant versions of the little green rings that the throttle line is coiled through? Are they unmagnetized iron cylinders? My Eflite 1.5 P-51 had something like this but that one was wrapped around all the servo wires. Is that the same? Would you put one of these around both pairs of ESC cables?
Is there a way to measure the amount of RF signals coming off the power cables? What about the batteries themselves? Don't they put out RF? That being the case, since the current flows from the battery to the ESC, isn't there going to be RF all along the way, not just close to the ESCs?

[GliderGuy]

Hi xviper - The variety pack has all sizes. The largest is about the size of your thumb. I believe the Amazon page shows dimensions. The Amazon page has plenty of photos that answer your questions. They clip on.

Put them as close to the ESC as possible to block the RF noise at the source. The portion of the wires after the choke is clean and not carrying RF noise.

You can go hog wild. These are light and small. The HAM guy said, “Put one on EVERY wire coming from the ESC....but the 3 wires from the ESC to the motor are not as critical because they don’t run up towards the receiver.”

He’s convinced it is the common mode RF noise from the ESC that is causing the loss of pointer handshake.

The rest????? Are there any EEs out there with the equipment?

Ferrite- a ceramic compound consisting of a mixed oxide of iron and one or more other metals. Ferrite has ferromagnetic properties and is used in high-frequency electrical systems.


-GG

[themudduck]

Here's one more pic. I opened up the throttle and flew a little too fast I think.

[xviper]

Hi xviper - The variety pack has all sizes. The largest is about the size of your thumb. I believe the Amazon page shows dimensions. The Amazon page has plenty of photos that answer your questions. They clip on.

You can go hog wild. These are light and small. The HAM guy said, “Put one on EVERY wire coming from the ESC....but the 3 wires from the ESC to the motor are not as critical because they don’t run up towards the receiver.”

He’s convinced it is the common mode RF noise from the ESC that is causing the loss of pointer handshake.

The rest????? Are there any EEs out there with the equipment?

Ferrite- a ceramic compound consisting of a mixed oxide of iron and one or more other metals. Ferrite has ferromagnetic properties and is used in high-frequency electrical systems.


-GG

I don't know if everything you've said has got my wheels turning or if it's just superstition running amok, but went down to find that choke I took out of the Mustang and I clamped it over all 4 power leads to the ESCs in the Mig. It's the most expensive plane I've purchased to date and I want it to survive beyond my "dumb thumbs". If this little choke is like a lucky rabbit's foot, I'll take it. I've never seen quite so many crashes on a new plane as I've seen reported for this one.

[xviper]

Here's one more pic. I opened up the throttle and flew a little too fast I think.

"Angel wings". I hope it didn't die and go to heaven.

[HaroldAnderson]

https://youtu.be/tBn4iuXrhkg
Here’s the video to accompany my previous post- sorry for the potato quality, we were using the good camera for photos.

It may be just the camera angle but the plane looks like it was on the verge of a stall to me. When you pulled up flaps that might have been the last straw. What do others think on this video? I've gotten too slow with jets several times turning onto final and that is how mine looked. Sorry to see that. Glad it isn't too bad. I've got the same afterburners in mine and it looks awesome. 6 flights on it so far.

Edit: I just noticed you said the flaps and gear were still down after the crash.

[GliderGuy]

I don't know if everything you've said has got my wheels turning or if it's just superstition running amok, but went down to find that choke I took out of the Mustang and I clamped it over all 4 power leads to the ESCs in the Mig. It's the most expensive plane I've purchased to date and I want it to survive beyond my "dumb thumbs". If this little choke is like a lucky rabbit's foot, I'll take it. I've never seen quite so many crashes on a new plane as I've seen reported for this one.

Don’t forget....all wires form BOTH ESCs.
I have a set of chokes on both sides of the aft battery. One set per ESC.

I did not put any on the motor side of the ESCs.
-GG

[DCORSAIR]

It may be just the camera angle but the plane looks like it was on the verge of a stall to me. When you pulled up flaps that might have been the last straw. What do others think on this video? I've gotten too slow with jets several times turning onto final and that is how mine looked. Sorry to see that. Glad it isn't too bad. I've got the same afterburners in mine and it looks awesome. 6 flights on it so far.

Edit: I just noticed you said the flaps and gear were still down after the crash.

I was waiting for someone to say it first, it looks like a stall to me as well, maybe its not and you find a problem, but I have seen that too many times from jet guys and myself included, it just looked to slow to me.