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Official Freewing 90mm F-4 Phantom II Thread

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  • Originally posted by GliderGuy View Post
    Great advice locharrow! Thanks Hugh. I copied your post...saving for when I upgrade to a higher end xmitter.

    One additional tip Dave...Of the 3 I have flown, every one had a wing roll left on the maiden. Took about 3-4 clicks of right aileron trim. You may wish to preset your trim and avoid the SURPRISE. See photo..

    MRC customer service guy says he did the same on his.

    -GG
    Click image for larger version Name:	4354D610-5879-4A33-B701-7CC601D9E00B.jpeg Views:	0 Size:	120.4 KB ID:	310673
    I"ll add some right trim for that eventuality! Thanks!

    Comment


    • Found this video on setting up Flight Modes. He uses it for slightly different things not tied to the flap switch, but the theory is the same.

       
      Hugh "Wildman" Wiedman
      Hangar: FL/FW: Mig 29 "Cobra", A-10 Arctic, F18 Canadian & Tiger Meet, F16 Wild Weasel, F4 Phantom & Blue Angel, 1600 Corsair & Spitfire, Olive B-24, Stinger 90, Red Avanti. Extreme Flight-FW-190 Red Tulip, Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, MXS Green, & Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51.

      Comment


      • Originally posted by GliderGuy View Post
        Hi Davegee.....

        Pretty critical / need to get it CORRECT.

        With flaps up (no flaps)...adjust per the photo below. Then to the left of the photo the manual says....(and I am adding text for clarity)
        FULL FLAPS AND HIGH RATE 5 mm more nose up elevator (this means the front edge will now be 13 mm below the seam)
        FULL FLAPS AND LOW RATE 3.5 mm more nose up elevator (this means the front edge will now be 11.5 mm below the seam)

        Don’t overdo the mix!!! Make sure everything is the same on both sides.

        Basically, the bird pitches nose down when the flaps are lowered....so the mix counters this.

        If you have your CG aft of the manual recommendation, reduce the above amounts a little.

        -GG


        Photo of trim setting....Flaps up
        Transmitter elevator trim slows “0” or neutral and the elevator stick is in the middle....no stick pressure applied.


        Click image for larger version Name:	B3EDC837-9283-4767-88E9-C01556C5A8E6.jpeg Views:	0 Size:	28.1 KB ID:	310605
        Hi Glider Guy: after taking in your comments and those of Hugh, I'll do the takeoff flaps up and not attempt to work with flaps until I'm at a safe altitude. If need be, I"ll land with no flaps. I do have brakes so that should keep it from going off of the end of the runway into the sagebrush!

        Two questions:
        1) My field is at 5000' MSL. Would that affect at all your endorsement at all of taking off with no flaps on the maiden?

        2) Just to confirm: I have my stabilizer set correctly now, I think: With electrical power on, flaps up, the stab is down 8mm from the seam. When I select LOW rate Landing flaps, the stab is at 11.5mm down from the seam. And when I'm at intermediate flaps, takeoff or maneuvering flaps setting, I sort of split the difference, around 10 mm down from the seam. It's not really a whole lot of travel from the neutral position between flaps up and full flaps, but I guess it doesn't have to be at the speed it is flying.
        Do these numbers sound ok to you for my maiden flight?
        Thanks!

        Comment


        • Originally posted by davegee View Post

          Hi Glider Guy: after taking in your comments and those of Hugh, I'll do the takeoff flaps up and not attempt to work with flaps until I'm at a safe altitude. If need be, I"ll land with no flaps. I do have brakes so that should keep it from going off of the end of the runway into the sagebrush!

          Two questions:
          1) My field is at 5000' MSL. Would that affect at all your endorsement at all of taking off with no flaps on the maiden?

          2) Just to confirm: I have my stabilizer set correctly now, I think: With electrical power on, flaps up, the stab is down 8mm from the seam. When I select LOW rate Landing flaps, the stab is at 11.5mm down from the seam. And when I'm at intermediate flaps, takeoff or maneuvering flaps setting, I sort of split the difference, around 10 mm down from the seam. It's not really a whole lot of travel from the neutral position between flaps up and full flaps, but I guess it doesn't have to be at the speed it is flying.
          Do these numbers sound ok to you for my maiden flight?
          Thanks!
          Hi Dave,

          1) I've flown EDFs at 5,000 MSL with cooler temps (70F to 80F) and had no issues. Be ready to counter a bump in the runway causing an unexpected nose-high bounce into the air. The thrust line on the F-4 is not like that of the MiG-29, so this is less of a problem for the F-4. It can be a BIG problem for the MiG.
          2) Every bird is different...just expect settings to be "close" for maidens with tweaking necessary.
          3) Set your timer for no more than 3 min on your first flights (assuming a 5000 or 6000 mAh battery), so get busy early on in the flight with tweaking your trims and experimenting with your flaps mix. Report your success!

          -GG

          Comment


          • Originally posted by GliderGuy View Post

            Hi Dave,

            1) I've flown EDFs at 5,000 MSL with cooler temps (70F to 80F) and had no issues. Be ready to counter a bump in the runway causing an unexpected nose-high bounce into the air. The thrust line on the F-4 is not like that of the MiG-29, so this is less of a problem for the F-4. It can be a BIG problem for the MiG.
            2) Every bird is different...just expect settings to be "close" for maidens with tweaking necessary.
            3) Set your timer for no more than 3 min on your first flights (assuming a 5000 or 6000 mAh battery), so get busy early on in the flight with tweaking your trims and experimenting with your flaps mix. Report your success!

            -GG
            All great suggestions. Wilco on the flight report after the maiden, whenever I do that!
            Thanks!

            Comment


            • Originally posted by davegee View Post

              Hi Glider Guy: after taking in your comments and those of Hugh, I'll do the takeoff flaps up and not attempt to work with flaps until I'm at a safe altitude. If need be, I"ll land with no flaps. I do have brakes so that should keep it from going off of the end of the runway into the sagebrush!

              Two questions:
              1) My field is at 5000' MSL. Would that affect at all your endorsement at all of taking off with no flaps on the maiden?

              2) Just to confirm: I have my stabilizer set correctly now, I think: With electrical power on, flaps up, the stab is down 8mm from the seam. When I select LOW rate Landing flaps, the stab is at 11.5mm down from the seam. And when I'm at intermediate flaps, takeoff or maneuvering flaps setting, I sort of split the difference, around 10 mm down from the seam. It's not really a whole lot of travel from the neutral position between flaps up and full flaps, but I guess it doesn't have to be at the speed it is flying.
              Do these numbers sound ok to you for my maiden flight?
              Thanks!
              I believe the altitude will affect your take-off with no flaps. I also think you're psyching yourself out regarding using flaps. I would still suggest you use take off flaps and soon after getting it airborne, put the flaps up and the gear. If you get the Flight Modes in, then just fly it around at about 60-70% throttle and do your trims. Then drop the gear and go to take-off flaps and trim there. Once you get it stable, go to landing flaps and trim there. It shouldn't be too wonky, but if it does, just flip the switch back to flaps up and fly there. Once configured for landing, fly it around that way to get comfortable before landing.

              Set your timer at first to 3:00 or less (I set mine at 4:00, but use a 6000 mah battery, CG about 6-8mm aft of manual and fly with the 12 blade inrunner). Landing with full flaps (assuming you have been able to trim it out there) is much easier than going in without them. You definitely need to slow down to a reasonable speed to land with the nose slightly up (if the nose wheel hits first, bad things can happen, like bucking bronco and possibly breaking the nose gear pin) and full flaps will help. Coming in with no flaps will result in your "best possible landing" to be a three pointer. At that speed, trying to get the nose up for a main gear first landing will mostly likely end up with the aircraft gaining altitude instead of going high (or low to moderate) alpha forcing a go around. On my landing approach on the downwind leg, I'll drop the throttle to about 45%, do a slow gentle turn to line up the runway and then drop the throttle to 28% until I'm about 3-4 feet off the ground, reduce the throttle to 18-20% and ease in some up elevator to get the nose slightly up without it gaining any altitude, then slowly reduce the throttle and let it settle on the runway flaring about a foot off the runway. My worse landings were early on when I got too nervous and tried to land with too much speed, in fear of a wing stall. If you're low enough to the runway, the F-4 will glide a little bit with the ground effect. On the other hand, the F-4 will wing stall fairly easily and severely dip it's left wing, so it's important to determine just how slow you can fly in your landing configuration before it stalls, because once it does at low altitude, game over.

              What other EDF's do you have? I only ask to suggest what the F-4 in landing is similar to. For me, landing is fairly similar to my Stinger 90, but the F-4 lands a little heavier and slightly faster. It's not like landing my F-16 or F-18 which both like to get their arrogant snouts up on landing fairly easy, but then I have those balanced 10-25mm further aft from recommended.
              Hugh "Wildman" Wiedman
              Hangar: FL/FW: Mig 29 "Cobra", A-10 Arctic, F18 Canadian & Tiger Meet, F16 Wild Weasel, F4 Phantom & Blue Angel, 1600 Corsair & Spitfire, Olive B-24, Stinger 90, Red Avanti. Extreme Flight-FW-190 Red Tulip, Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, MXS Green, & Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51.

              Comment


              • davegee take a look at the attached video flown on grass and it will give you an idea of the take-off run (at about 0:55) and fast forward to the landing at the end which may help in giving you a visual reference of landing speed. It's definitely not slow like the Avanti, F-16 of F18, I'll say that much, so flaps will definitely help out.

                 
                Hugh "Wildman" Wiedman
                Hangar: FL/FW: Mig 29 "Cobra", A-10 Arctic, F18 Canadian & Tiger Meet, F16 Wild Weasel, F4 Phantom & Blue Angel, 1600 Corsair & Spitfire, Olive B-24, Stinger 90, Red Avanti. Extreme Flight-FW-190 Red Tulip, Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, MXS Green, & Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51.

                Comment


                • Originally posted by Hugh Wiedman View Post

                  I believe the altitude will affect your take-off with no flaps. I also think you're psyching yourself out regarding using flaps. I would still suggest you use take off flaps and soon after getting it airborne, put the flaps up and the gear. If you get the Flight Modes in, then just fly it around at about 60-70% throttle and do your trims. Then drop the gear and go to take-off flaps and trim there. Once you get it stable, go to landing flaps and trim there. It shouldn't be too wonky, but if it does, just flip the switch back to flaps up and fly there. Once configured for landing, fly it around that way to get comfortable before landing.

                  Set your timer at first to 3:00 or less (I set mine at 4:00, but use a 6000 mah battery, CG about 6-8mm aft of manual and fly with the 12 blade inrunner). Landing with full flaps (assuming you have been able to trim it out there) is much easier than going in without them. You definitely need to slow down to a reasonable speed to land with the nose slightly up (if the nose wheel hits first, bad things can happen, like bucking bronco and possibly breaking the nose gear pin) and full flaps will help. Coming in with no flaps will result in your "best possible landing" to be a three pointer. At that speed, trying to get the nose up for a main gear first landing will mostly likely end up with the aircraft gaining altitude instead of going high (or low to moderate) alpha forcing a go around. On my landing approach on the downwind leg, I'll drop the throttle to about 45%, do a slow gentle turn to line up the runway and then drop the throttle to 28% until I'm about 3-4 feet off the ground, reduce the throttle to 18-20% and ease in some up elevator to get the nose slightly up without it gaining any altitude, then slowly reduce the throttle and let it settle on the runway flaring about a foot off the runway. My worse landings were early on when I got too nervous and tried to land with too much speed, in fear of a wing stall. If you're low enough to the runway, the F-4 will glide a little bit with the ground effect. On the other hand, the F-4 will wing stall fairly easily and severely dip it's left wing, so it's important to determine just how slow you can fly in your landing configuration before it stalls, because once it does at low altitude, game over.

                  What other EDF's do you have? I only ask to suggest what the F-4 in landing is similar to. For me, landing is fairly similar to my Stinger 90, but the F-4 lands a little heavier and slightly faster. It's not like landing my F-16 or F-18 which both like to get their arrogant snouts up on landing fairly easy, but then I have those balanced 10-25mm further aft from recommended.
                  Hi Hugh: good info there. I flew the SEA paint scheme version for a couple of years, probably got maybe 50 flights on it. Decided to retire it as it had developed a bunch of weird electronic glitches and didn't feel safe trying to fly it again. It is going to the local Civil Air Patrol unit nearby and we'll hang it in their hangar where they house a real Cessna 182 for their SAR missions.
                  I've had an F-15,, two F/A-18s, two F-14s, a DeHavilland Venom, one of my favorites, an F-86, T-33, A-6, A-4, probably some others, too. I like to fly the jets as well as the prop warbirds.

                  cheers
                  davegee

                  Comment


                  • Well, That could have gone better!! I took my F-4 out for its maiden this morning. Perfect weather very slight breeze right down the runway. Took off at the very approach end of the runway, so I had the full 600 feet or so. Did taxi tests, brake tests, and range checks again before the takeoff attempt. Set flaps up for this first go. The plane accelerated normally as I expected it to do, but still didn't take off, All of a sudden it started weaving hard left and right on the runway without any inputs from me. I decided to take it up in the air as I was too far and too fast down the runway to abort. An abort out here when the plane goes off the end of the runway usually ends up with a highly damaged or destroyed plane, due to the sagebrush and gopher holes everywhere.
                    The plane got about 3 feet into the air, but the wings were wagging so I knew it was just above a stall, and if I tried to horse it around the pattern, it would stall and spin in.. So I pulled the power back and landed it as best I could off the side of the runway.

                    The cheap, plastic mounts for both main gear, barely glued in, pulled the main gear out and will have to be replaced. The nose gear still cycles, but the casing for the retract is cracked, so it will have to be replaced. Other than than, several areas of cosmetic scratches and gouges on the underneath of the airplane, but I'm used to fixing those so you can't tell they were there.

                    Analysis.: That violent sashaying left and right of the centerline well into the takeoff roll, was disturbing. Hadn't seen that before. I'm thinking that one or possibly both of the set screws for the gear at the factory were not tight enough, even though I tugged on them and they seemed to be pretty solid while I was putting it together. Nonetheless, I think they got loose somehow, one, or both, as the plane was rapidly accelerating down the runway. This violent yawing at near takeoff speed I think really took a lot of energy out of the plane, and it was barely flyable when I pulled it off the runway.

                    That is where I put the cause of the incident. Although I don't remember every physically putting the 2.0mm wrench in a new plane before to test them as they have always been solid, in this case, I'm guessing they were tightened somewhat, but not nearly where they should have been, even though tugging on them during assembly, as I said above, seemed to be solid. I think the Chinese got the best of me this time! I think the plane would have flown just fine had this issue not happened. Rest assured, I will ALWAYS stick the wrench in every set screw and tighten it down hard, or confirm that it is already set to go in the future. Probably a good thing for all of us to do, although I suppose most of you guys already do that.

                    I'll order the replacement parts, do the minor cosmetic repairs and retry when I get everything together again. It is definitely repairable, and it will see the skies again soon!

                    Davegee

                    Comment


                    • That’s weird. I have never had an F-4 do that. Your assessment as to the cause is as good as any.

                      Glad you got only minor damage. My loss of the FFS servo on approach a few weeks ago resulted in similar damage plus a broken back near the intakes.

                      Got the spare parts in, cosmetic stuff fixed, and she’s flying good as new. So, take heart.

                      -GG

                      Comment


                      • Originally posted by davegee View Post
                        Well, That could have gone better!! I took my F-4 out for its maiden this morning. Perfect weather very slight breeze right down the runway. Took off at the very approach end of the runway, so I had the full 600 feet or so. Did taxi tests, brake tests, and range checks again before the takeoff attempt. Set flaps up for this first go. The plane accelerated normally as I expected it to do, but still didn't take off, All of a sudden it started weaving hard left and right on the runway without any inputs from me.
                        The plane got about 3 feet into the air, but the wings were wagging so I knew it was just above a stall, and if I tried to horse it around the pattern, it would stall and spin in.. So I pulled the power back and landed it as best I could off the side of the runway.
                        Analysis.: That violent sashaying left and right of the centerline well into the takeoff roll, was disturbing. Hadn't seen that before. I'm thinking that one or possibly both of the set screws for the gear at the factory were not tight enough, even though I tugged on them and they seemed to be pretty solid while I was putting it together. Nonetheless, I think they got loose somehow, one, or both, as the plane was rapidly accelerating down the runway. This violent yawing at near takeoff speed I think really took a lot of energy out of the plane, and it was barely flyable when I pulled it off the runway.

                        I'll order the replacement parts, do the minor cosmetic repairs and retry when I get everything together again. It is definitely repairable, and it will see the skies again soon!

                        Davegee
                        DG, so sorry to hear that, definitely didn't expect that and was sure you'd be coming back with a glowing report. You must be correct in the analysis as that "runway wagging" certainly doesn't sound like some aerodynamic issue. I always check the set screws on a new aircraft before maiden, but honestly don't remember one ever being loose, but then that's not a highly confident statistical analysis. Now that you have the aircraft on the bench, are the main and nose gear struts loose on the retract pins in any way? What about the wheels on the axels, do they spin straight without a wobble? If those areas seem secure, maybe the problem is the gear mounts were not sufficiently secured/glued in place and one (or both) came loose during the take-off run? Did the plastic mounts look like they tore a lot of foam out when they came out, or did they look like they came out kind of clean? My first F-4 crashed on take-off of it's second flight when the servo wire for the elevator got melted by the ESC. (Yes, some idiot mechanic/builder missed the channel for the servo wires and ended up running the wire right over the ESC). It never got off the runway but ran off the end at full throttle into heavy grass. Both plastic gear mounts came out and they kind of looked like they didn't have enough glue holding them in, but to be honest, at that speed and the amount of force it put on those mounts, it wouldn't have made much difference, so don't expect those mounts to stay in place with a hard forced landing.

                        I have another possible theory. I fly off grass, but believe this would be more pronounced on asphalt. If there is more downward pressure on the nose wheel vs the main wheels, some of my EDF's (including the F4) get a little "wonky shimmy" (what ever that is) as it just about reaches take-off speed. This is from basically "riding" on the nose wheel and it is somewhat unstable since the nose wheel is so much smaller and you're now tracking on that one only. Flying EDF's off grass requires me to start with substantial up elevator to keep the nose wheel from digging into the grass and severely slowing down the take-off run. Once it gains a decent amount of speed, but before it's ready to lift off, I have to reduce the up elevator to something like 5-10% up and then it lifts off by itself when it reaches the correct speed. This ensures that there is always more pressure on the mains, and less on the nose wheels. Occasionally, I'll forget to do this and notice the aircraft seems to get "loose" from the ground around the mid section, but the nose is still firmly planted and it will wobble. I don't know if that may have any bearing on you're experience, but offer it just in case. I also still believe you should not worry about flaps and use them for taking off. I reduced the flap deflections of my maidens by about 40% for both until I flew it a few times and felt comfortable, then put them at full recommendations. Honestly, wish I would have started at the full amount as taking off and landing was easier than when I had them reduced.

                        If all the set screws and axels seem tight, I still doubt the gear mounts are the problem, so we need to solve this so you're not nervous about taking it up again. Mishaps are bad enough, not being convinced of the cause is even worse!
                        Hugh "Wildman" Wiedman
                        Hangar: FL/FW: Mig 29 "Cobra", A-10 Arctic, F18 Canadian & Tiger Meet, F16 Wild Weasel, F4 Phantom & Blue Angel, 1600 Corsair & Spitfire, Olive B-24, Stinger 90, Red Avanti. Extreme Flight-FW-190 Red Tulip, Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, MXS Green, & Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51.

                        Comment


                        • One last thought davegee . Of my EDF's the only one that I take off without flaps is the Avanti, simply because I'm lazy and it doesn't really need it on grass. If I accelerate with the elevator in neutral position, at some point when it's about near take-off speed, it seems to rise up from the rear first (even though I have it fully trimmed out level for flaps up), and get's a little wobbly as the nose wheel is still in the grass. Although this is not equivalent to the F-4 in weight, it sounds similar to what happened to you. Of course with the Avanti, it is so much lighter and I can just horse it in the air with no issues, I image that if it were the F-4, it might cause some real issues. If I use flaps for the Avanti, it does not happen. Don't forget, you will get more wing lift with flaps at a slower speed, so if you are taking off with the F-4 without flaps, you need more ground speed to get airborne than you would with flaps and it may be riding with too much "weight" on the nose wheel, causing it to potentially wobble at that greater speed. A buddy at our field who regularly competes (and has won several times) at the Top Gun competition, likes to fly my F-4/F-18 with full flaps for take-off. His main focus is large turbines, but enjoys flying my "little EDF foamies" for a break and has told me he uses full flaps because he want's it out of the grass as soon as possible because these aircraft are a "poor race car" on the ground at high speeds. I know guys take off all the time with these jets on asphalt without flaps, but I think if you do, you need to hold a little up elevator through the take-off run to keep the pressure and weight balanced on the 2 main gear wheels and not on the nose wheel. Just a thought.
                          Hugh "Wildman" Wiedman
                          Hangar: FL/FW: Mig 29 "Cobra", A-10 Arctic, F18 Canadian & Tiger Meet, F16 Wild Weasel, F4 Phantom & Blue Angel, 1600 Corsair & Spitfire, Olive B-24, Stinger 90, Red Avanti. Extreme Flight-FW-190 Red Tulip, Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, MXS Green, & Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51.

                          Comment


                          • Originally posted by Hugh Wiedman View Post

                            DG, so sorry to hear that, definitely didn't expect that and was sure you'd be coming back with a glowing report. You must be correct in the analysis as that "runway wagging" certainly doesn't sound like some aerodynamic issue. I always check the set screws on a new aircraft before maiden, but honestly don't remember one ever being loose, but then that's not a highly confident statistical analysis. Now that you have the aircraft on the bench, are the main and nose gear struts loose on the retract pins in any way? What about the wheels on the axels, do they spin straight without a wobble? If those areas seem secure, maybe the problem is the gear mounts were not sufficiently secured/glued in place and one (or both) came loose during the take-off run? Did the plastic mounts look like they tore a lot of foam out when they came out, or did they look like they came out kind of clean? My first F-4 crashed on take-off of it's second flight when the servo wire for the elevator got melted by the ESC. (Yes, some idiot mechanic/builder missed the channel for the servo wires and ended up running the wire right over the ESC). It never got off the runway but ran off the end at full throttle into heavy grass. Both plastic gear mounts came out and they kind of looked like they didn't have enough glue holding them in, but to be honest, at that speed and the amount of force it put on those mounts, it wouldn't have made much difference, so don't expect those mounts to stay in place with a hard forced landing.

                            I have another possible theory. I fly off grass, but believe this would be more pronounced on asphalt. If there is more downward pressure on the nose wheel vs the main wheels, some of my EDF's (including the F4) get a little "wonky shimmy" (what ever that is) as it just about reaches take-off speed. This is from basically "riding" on the nose wheel and it is somewhat unstable since the nose wheel is so much smaller and you're now tracking on that one only. Flying EDF's off grass requires me to start with substantial up elevator to keep the nose wheel from digging into the grass and severely slowing down the take-off run. Once it gains a decent amount of speed, but before it's ready to lift off, I have to reduce the up elevator to something like 5-10% up and then it lifts off by itself when it reaches the correct speed. This ensures that there is always more pressure on the mains, and less on the nose wheels. Occasionally, I'll forget to do this and notice the aircraft seems to get "loose" from the ground around the mid section, but the nose is still firmly planted and it will wobble. I don't know if that may have any bearing on you're experience, but offer it just in case. I also still believe you should not worry about flaps and use them for taking off. I reduced the flap deflections of my maidens by about 40% for both until I flew it a few times and felt comfortable, then put them at full recommendations. Honestly, wish I would have started at the full amount as taking off and landing was easier than when I had them reduced.

                            If all the set screws and axels seem tight, I still doubt the gear mounts are the problem, so we need to solve this so you're not nervous about taking it up again. Mishaps are bad enough, not being convinced of the cause is even worse!
                            Hi Hugh: I'm fairly confident that it was the set screws installed at the factory that were not fully tightened. When I recovered the aircraft to inspect it, both pins for each main gear had pulled out, and when I put them back in the holes again, they were totally loose in there, e.g., the set screws were not fully in place. The problem didn't manifest itself until near takeoff speed when one or both started moving in its mount like a castering tailwheel that hasn't been locked in place and is now swerving all over the place. If I had had more runway, I could and would have aborted even then, and used the brakes to come to an uneventful stop to then discover the problem. But per the field conditions just outside the runway bounds, I wasn't comfortable doing that, for fear of totally messing up my plane in the rough sagebrush and gopher holes.

                            The thin plastic main gear mounts were pulled out violently when I landed it off the side of the runway, and have to be replaced. There was barely any glue applied at the factory to keep them in! Of course, Motion is out of them so I ordered all my parts on RC Castle, who had everything I needed.

                            I'm not going to be phazed by this incident. Once I do the repairs and thoroughly test it out again, I expect to have a normal takeoff and hopefully a successful maiden. The way the plane violently swerved either side of the runway, and then seeing that the pins on the main gear would just slip out due to the loose set screws, I'm pretty sure that was the source of the problem. I'm always so very careful trying to check every fitting, nut, bolt, set screw, etc,, but in this case, I think it was tightened just enough at the factory to seem secure and it was during taxi tests, like a rock. But when they let loose at that speed, it was a bad situation to be in.

                            As I said, the damage was relatively minor, and although I have to wait for the parts to come from China, I can have the rest of the plane ready to go by the time they get here. Should be up with that plane in a month or so, hopefully, and will report back on the NEXT maiden!! I think next flight I will do my normal thing as I have with all my previous jets, using takeoff flaps from the first go. I am comfortable that the flight controls, CG, and all that stuff will make them relatively stable so I can trim the plane easily on that first flight.

                            Thanks for your helpful tips and comments.

                            Davegee

                            Comment


                            • Originally posted by GliderGuy View Post
                              That’s weird. I have never had an F-4 do that. Your assessment as to the cause is as good as any.

                              Glad you got only minor damage. My loss of the FFS servo on approach a few weeks ago resulted in similar damage plus a broken back near the intakes.

                              Got the spare parts in, cosmetic stuff fixed, and she’s flying good as new. So, take heart.

                              -GG
                              Thanks, GG. I am pretty confident as to the reason the plane did what it did. I'll have it back up in the air again!

                              davegee

                              Comment


                              • Originally posted by davegee View Post

                                Thanks, GG. I am pretty confident as to the reason the plane did what it did. I'll have it back up in the air again!

                                davegee
                                Hugh makes some great points! My instructors called this “wheelbarrowing”...in a tricycle gear plane, things get squirrelly when it happens.

                                For another point of reference, flying off concrete...I begin my run with no flaps and central stick. About 1/2 way to take-off speed, I feed in “some” up elevator and continue the run. If she doesn’t break ground, I add a bit more up.

                                Analysis of this profile = little chance of wheelbarrowing

                                -GG

                                PS - While not immune to bad habits while moving at at high speed on the ground, she’s usually pretty well behaved.

                                bad behavior = bucking broncho typically snaps nose gear pin

                                Or a really odd pattern of nose wheel, then one main, then the other main, then nose wheel....fast repeat. Sort of a Dutch Roll but on the ground.

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                                • Tough one Dave. I've had to tighten the set screw on one of the mains a few times but it never misbehaved on take off. Even loose it should castor in line with the other two. I'd be looking very closely at the front end. Don't worry...mine survived a tree encounter needing a team of professional arborists to rescue it, a few weeks later, landing in a bush with very minor damage and being attacked by a dog! Still flies great and still looks mean as hell on a low pass!

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                                  • Originally posted by locharrow View Post
                                    Tough one Dave. I've had to tighten the set screw on one of the mains a few times but it never misbehaved on take off. Even loose it should castor in line with the other two. I'd be looking very closely at the front end. Don't worry...mine survived a tree encounter needing a team of professional arborists to rescue it, a few weeks later, landing in a bush with very minor damage and being attacked by a dog! Still flies great and still looks mean as hell on a low pass!
                                    It was a weird one, for sure. Upon further review, I found that I think I still use the plastic gear mounts for the main gear, and my old SEA paint scheme F-4 that is going to the local Civil Air Patrol squadron as a hanging display in their hangar is now being "picked" for parts that I could use and ones they'll never miss. For instance, the nose gear servo works perfectly on the old F-4, so, I'm removing that for the new plane. With any luck at all, if I can use all these parts and make the repairs ok, I might be able to get this thing up in the air in another week for another go at it. We'll see.

                                    Cheers
                                    davegee

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                                    • Dave, sorry about the maiden. While I have had, heard of, loose, or not tight enough struts it's rare... Good to hear your positive about it. The F-4 is a worthy plane.

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                                      • Originally posted by davegee View Post

                                        Hi Hugh: I'm fairly confident that it was the set screws installed at the factory that were not fully tightened. When I recovered the aircraft to inspect it, both pins for each main gear had pulled out, and when I put them back in the holes again, they were totally loose in there, e.g., the set screws were not fully in place. The problem didn't manifest itself until near takeoff speed when one or both started moving in its mount like a castering tailwheel that hasn't been locked in place and is now swerving all over the place. If I had had more runway, I could and would have aborted even then, and used the brakes to come to an uneventful stop to then discover the problem. But per the field conditions just outside the runway bounds, I wasn't comfortable doing that, for fear of totally messing up my plane in the rough sagebrush and gopher holes.

                                        Thanks for your helpful tips and comments.

                                        Davegee
                                        DG, then it definitely sounds like the set screws, good to know that the Aviation Safety Board has determined the cause! Another episode of Air Disasters with a potentially happy ending, at least there were no fatalities (as in a totaled F4). At least that's a simple fix to cure the problem.
                                        Hugh "Wildman" Wiedman
                                        Hangar: FL/FW: Mig 29 "Cobra", A-10 Arctic, F18 Canadian & Tiger Meet, F16 Wild Weasel, F4 Phantom & Blue Angel, 1600 Corsair & Spitfire, Olive B-24, Stinger 90, Red Avanti. Extreme Flight-FW-190 Red Tulip, Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, MXS Green, & Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51.

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                                        • Originally posted by Hugh Wiedman View Post

                                          DG, then it definitely sounds like the set screws, good to know that the Aviation Safety Board has determined the cause! Another episode of Air Disasters with a potentially happy ending, at least there were no fatalities (as in a totaled F4). At least that's a simple fix to cure the problem.
                                          I've had some success today on the repair to the F-4. I've installed the nose gear retract from my old SEA F-4, and also the nose gear landing gear door. The retracts are back in place now, and I guess in theory, I could fly tomorrow. But I'm trying to make all the cosmetic fixes to all the minor damage to the airplane, and will continue on that tomorrow. I hope to try the maiden again, next week. I guess the maiden actually worked a little today, I think it attained an altitude of 3 feet before it came crashing down!

                                          I'm upset with Motion for sending me a product that was defective, and one that I normally would never have checked with the wrench, as it felt secure, but wasn't. But I guess it's part my fault too, for not checking it myself, although I've Never had an issue with any of my many foamies over the years with loose set screws in that area before. But I am aware of that now, and will always check Every connection in the airplane. It's good all of us do the same, or suffer the consequences if you don't.

                                          Cheers

                                          Davegee

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