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Official Freewing MiG-29 Fulcrum Twin 80mm Thread

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  • I agree but I think some crashes at the beginning were people not paying attention to CG, they saw only the front and rear battery areas and flew with too nose heavy a CG and didn't have enough pitch response (travel or servo power) to get them out of a situation. Then all the servo discussions happened and FW came out with slightly better servos and finally much better ones along with better hardware. Now a lot of us have TV's. I don't think any of these are fixes, that there is an airframe issue with this particular bird and either we haven't found the true root cause or the tru fix can't happen without major wing/ fuselage work.

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    • Funny, don’t you think, that the twin 80mm F-14 which is a heavy plane, does not need beefed up FFS servos or hardware. What it has is a more rigid tail structure and a stab pivot axis that is located better.

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      • Nope not funny…

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        • Well the other thing is that when you are in Alpha lock pushing the elevator down does absolutely nothing if you are at full throttle. That is the crucial problem.

          You're doing just about no forward speed and there is no windflow (like with a propeller) against the elevator that would make the elevator somehow effective. Now if you are not able to keep the plane level you don't know hat hit you. As soon as the nose is horizontal and accelerate again the natural reflex is to pull the elevator when at some forward speed and you're stuck again. That happened to me on the first flight.

          Does it also stay in alpha lock when inverted or does the airfoil help in preventing that?

          I paid like 850 EUR with VT. Now it's like another 250 EUR (FMS EDF) or 450 EUR (Wemotec EDF) to just get the MIG-29 to hopefully do what I could normally just expect it to do. Not trying to bash everyones toy - these are legitimate hobby wallet concerns.

          So now when in alpha lock:
          1. Reduce throttle until nose comes down
          2. Push elevator and pick up speed by going downward
          3. Have at least 30 meters of height - that's what the cool videos seem to indicate

          or

          Switch on VT, pull elevator, do a backward flip and go off throttle when the nose is pointing down. And switch off the VT immediately when nose is pointing down until you're in stable flight. Accelerate level and / or a bit downwards. I found pushing the VT down results in a massive loss of height if you are too late in going level (which is tricky when using the VT). Keeping VT on would make the elevator stick just too sensitive for a saving manoeuvre once you are out of alpha lock, especially after some extra adrenalin.

          Basically a bit more power would be the solution. And alpha lock would be a very welcome stable awesome characteristic of the MIG-29.

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          • It doesn't do it inverted. I don't think additional power will be the solution at all, it'll just push you further into alpha lock. If you have TV full down with TV is my preferred way out.

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            • Originally posted by xviper View Post
              BINGO!

              Back when this plane was brand new, before the TV nozzles were even available, several crashes occurred in SE Asian - with videos. It was blamed on flying at high speed with the flaps deployed. First, why would anyone do that anyway? No matter. That was the assumption at the time. Before I got my VT nozzles, I did some tests to see what would happen if I slammed the flaps down at speed and see if the thing would fall out of the sky. This did NOT happen.
              Sounds like you are poo pooing the notion that deploying flaps causes the plane to pitch down uncontrollably? If so, I disagree. I was ready to land my plane and on the downwind leg at cruise speed hit the LG switch and without thinking also flipped the Flap switch. The plane instantly went into a steep dive and I could not recover using elevator control. Before I had time to realize what happened and retract the flaps the plane was in the ground. I'm now much more careful with my second Mig....I wait until the gear are out and the plane is slow before using flaps.

              I assume your tests were done properly and your jet didn't pitch down with flaps, but I assure you that not all Mig-29s act like that.

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              • Originally posted by Evan D View Post
                It doesn't do it inverted. I don't think additional power will be the solution at all, it'll just push you further into alpha lock.
                Well, if you have enough power to accelerate straight up it doesn't matter how far up the nose is pushed. When I had alpha lock during a takeoff the plane climbed vertically for a few meters but eventually ran out of climb performance. With enough thrust I assume it would have continued to climb to an altitude to effect a recovery.

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                • Do you honestly think ANYONE will ever get a pair of fans in the big Mig that can do that? Plus it'll take a lot of power, more than a normal plane in a normal high alpha state (think like a Mirage). The Mig would be just plowing through the air and need to overcome that natural high alpha lock that another plane doesn't have to fight. That other plane would not be in lock and still have pitch control and could use the extra thrust.

                  Either way until someone has a pair of fans that have 50% or more, maybe a lot more, thrust we won't know.

                  I'd be interested to see someone toss a couple 12S Jet Fans or Schubbies in...

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                  • Pretty disastrous.

                    Yes enough power would have been the game changer. Because more power would be more speed. And more speed would mean that the elevators get enough air flow to actually be effective. Simple as that. Needs more thrust at low speed than aeroplane weight. The full speed thrust is not really relevant in alpha lock. Maybe the EDF needs a redesign for more thrust at lower speed and sacrifice some top speed. And more thrust would simply push the MIG forward to a safer altitude.

                    A bigger higher KV motor on the EDF which could handle the higher Ampere with a larger ESC would be a solution.

                    Just wondering if I am better off getting the F-22 and keep the MIG-29 as long as it lasts. Hope the F-22 does not do this similarly.

                    I had the EFlite Havoc and it had some very nasty stall characteristics. Sudden wing tip stalls at decent speed during landing and in the air. Tore it apart (before damaging retracts and electronics) and put the EDF and retracts into a printed F86 and got the Freewing Avanti. Rather move on than deal with frustration. Expected similar quality like that of the Avanti from the MIG-29.

                    Basicially to me the MIG-29 is a jet that always has to stay at minimum medium speed to be a safe aeroplane.

                    Just wondering now if I should adjust the Thrust Vector to minimal permanent deflection with smaller elevator deflection and go to full TV and elevator deflection via switch to do fun stuff. (higher elevator and TV dual rate via switch). That might prevent the situation as in the video above. So that the TV shares the work with the elevator during normal flight already. Think that seems to be the first most common sense solution to me. Think I will do that. Seems like the elevators need quite some speed to be effective and working. Look at the full size jet aeroplanes and see their massive stabilizer deflections. So there is a point about having to have EDFs will substantially more power to make a difference.

                    Thanks for posting that video!


                    We have to keep manufacturers accountable. We need to point these things out, so they improve what they sell to us. It's our money, our fun time. And give us good excuses to buy the next aeroplane.

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                    • There is a big difference in thrust required at very low to zero airspeed AND in alpha lock (very draggy) and thrust required at very low to zero airspeed and NOT in alpha lock. Having more than 1:1 thrust is NOT a simple answer to the problem.

                      On mine I have triple rates for pitch and the TV is on all the time and also has triple rates. Each flight "mode", high speed, medium speed, post stall manuever requires it's own amount of surface and TV. In general the higher the airspeed the less stab and TV movement, in general. In zero airspeed alpha lock the stab movement is irrelevant and you want more TV throw and you are controlling pitch with throttle.

                      My favorite EDF is the Grippen, I just love it. I have three, on 8S repainted and with TV. One box stock no TV. And a spare in the box for when I lose either of my flying ones. I also like my F-22 and I've lightened it up, put in a Jet Fan/ HET 8S system using fairly light batteries and I put TVs on it. Another one I really like is the Arrows twin 6S 64mm MiG29, none of the issues that the FW MiG has, flies awesome. I am on my second one of those and also have a spare in the box in case.

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                      • Originally posted by radfordc View Post

                        Sounds like you are poo pooing the notion that deploying flaps causes the plane to pitch down uncontrollably? If so, I disagree. I was ready to land my plane and on the downwind leg at cruise speed hit the LG switch and without thinking also flipped the Flap switch. The plane instantly went into a steep dive and I could not recover using elevator control. Before I had time to realize what happened and retract the flaps the plane was in the ground. I'm now much more careful with my second Mig....I wait until the gear are out and the plane is slow before using flaps.

                        I assume your tests were done properly and your jet didn't pitch down with flaps, but I assure you that not all Mig-29s act like that.
                        I'm not "poo pooing" anything whatsoever. If it "sounds" like that to you, perhaps that's the way you interpreted it. All I'm doing is relating what was posted on the forums and on YouTube and what was said on the forums as a result of those early videos. I made no comments either way, just posting what theories and/or conclusions drawn by others. As far as showing that it did not happen to my Mig, that was my experience and I even got a video to prove it, which I posted early in this thread. I can only state what my experience is and I've never indicated what may or may not happen to others nor did I make any statements about any other Mig being like that or not being like that. You should not even make the assumption that I did the tests "properly", not knowing what your standards might be for "properly". I did it to see for myself and I shared that with those reading the forums. How they took it was and still is beyond my control.
                        PS. I've never stopped being careful with my Mig. It has characteristics that can be quite alarming and unpredictable. Your video shows that you went too vertical, too close to the ground. There was insufficient momentum to sustain that kind of attitude.

                        Insofar as powering this Mig enough to make it overcome it's own weight, that is going to be a very hefty project. It will never be able to do this:

                        It takes a tremendous amount of thrust to vertically lift a plane's weight and even more to get out alpha lock because then you're dealing with a plane already in motion and requesting a sudden and significant change in that motion.

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                        • Note the SA had no gear, had more than 1:1, and had TVs. And did not have a problem with alpha lock.

                          The Arrows Mig is a perfect comparison. No alpha lock issue, not quite 1:1, high alphas great and is able to get out of high alpha.

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                          • Originally posted by radfordc View Post

                            Well, if you have enough power to accelerate straight up it doesn't matter how far up the nose is pushed. When I had alpha lock during a takeoff the plane climbed vertically for a few meters but eventually ran out of climb performance. With enough thrust I assume it would have continued to climb to an altitude to effect a recovery.

                            You need enough thrust to hold the plane's weight in the air without losing altitude while the nozzles are tilting the plane to an attitude where it can get some forward airspeed, then the control surfaces can take over and "fly" the plane. This is how I get the SebArt to start flying out of a hover and/or high alpha.

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                            • Originally posted by Evan D View Post
                              Note the SA had no gear, had more than 1:1, and had TVs. And did not have a problem with alpha lock.

                              The Arrows Mig is a perfect comparison. No alpha lock issue, not quite 1:1, high alphas great and is able to get out of high alpha.
                              The SA is a different breed of Mig29. I believe it was designed specifically to hover and high alpha.

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                              • Agreed. The Arrows is different too, no alpha lock

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                                • Originally posted by Evan D View Post
                                  Agreed. The Arrows is different too, no alpha lock
                                  Can you give your assessment as to the design principles incorporated into the Arrows Mig as compared to the Freewing Mig that would make the Arrows resistant to alpha lock? As far as I can see, the Arrows is almost the same size as the SA but much heavier, no VT, flies on 6s.

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                                  • The Arrows is quite a bit smaller, about the size of the FW (or EF) 70mm F-16, maybe a tiny bit larger. I did some basic measuring a long time ago of the FW and Arrows to compare them within their scale percentages, Things like length to span and CG location that I decided on after flying (not book CG). Visually the wing angle of attack to fuselage line to thrust line all look different between the two and because of that the neutral spot for the stabs look different. That said I have no quantitative data.

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                                    • Still, some interesting observations. I've never even considered the Arrows Mig since I already had the SA and the FW. I had no idea that it was powered by 6s. A 6s in a little airframe like that could be a real exciting model to fly. I may have to take a serious look at one now.

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                                      • What is SA and FW?

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                                        • Sebart and FreeWing

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