F7F-3 Tigercat

You must Sign-in or Register to post messages in the Hobby Squawk community
Registration is FREE and only takes a few moments

Register now

Announcement

Collapse
No announcement yet.

Official Freewing 90mm F-4 Phantom II Thread

Collapse
X
Collapse
First Prev Next Last
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Originally posted by BenAtkinsonUK View Post
    TOTALLED IT ON MAIDEN....brown out? Worse??

    Well that was the worst RC experience of my life!
    Terrible morning in bloody shock I think.

    Here's what happened: First flight, pre flight all complete...everything was moving how it should....my AS3x receiver working as it should correcting as it should. Power test seemed fine....CoG was by the book.

    Took a long time to rotate but the grass hadnt been cut this week...anyway - it got airborne....climbed out fairly slowly, but got downwind and needed a lot of up trim (felt nose heavy)....started to feel a bit more comfortable...was picking up speed nicely....

    THEN

    Complete loss of power....the nose dropped (obviously was nose heavy despite getting the CoG right).....and thats it. Nose dived.

    DAMAGE:
    Nose cone SMASHED to a pulp
    front end to wing root ripped off
    battery damaged
    cockpit destroyed into pieces
    nose gear found some yards away, along with ESC and battery tray

    No idea if anything else is buggered.....

    WORST bit .....completely lost trust in this whole thing now. I don't know what caused that but I can't afford another and for it to happen again.

    I may just buy a fuselage and see if i can salvage something from it.

    Thanks for everyones help to set it up.

    GUTTED!

    Ben
    I'm at a total loss in figuring out what happened. The set-ups I gave you have worked fine on both my F-4's for almost 60 flights. I do fly them somewhat behind the 190 mm book CG at 192-194 mm, but that shouldn't have made that much difference. Check the elevator servo that it did not come loose or that there was a problem with the linkage.
    Hugh "Wildman" Wiedman
    Hangar: FlightLine-90mm F18 Canadian Demo, F16 Wild Weasel, F4 Phantom, F4 Blue Angel, 1600mm Corsair & Spitfire, Olive & Silver B-24, Stinger 90, Red 80mm Avanti. Extreme Flight-Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, 62" MXS Green, 62" Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51, Apprentice.

    Comment


    • Hugh, doesn't sound like setup... "complete loss of power..."

      Comment


      • Evan D you're right, sorry I was just extremely distressed when I heard about it as I helped with the TX and RX setup and feel somewhat as a contributing factor. Not as bummed as Ben, but not far behind. Just hate hearing it and the sinking notion that it could happen to any of us. It sounds like a brown out but wonder if the ESC, EDF or battery had anything to do with it. I fly mine off grass as well and even when it's not mowed recently, it takes off fine (unless the grass is covered in dew) and it sure climbs well after releasing off the runway, so Ben's take-off description didn't sound quite right.
        Hugh "Wildman" Wiedman
        Hangar: FlightLine-90mm F18 Canadian Demo, F16 Wild Weasel, F4 Phantom, F4 Blue Angel, 1600mm Corsair & Spitfire, Olive & Silver B-24, Stinger 90, Red 80mm Avanti. Extreme Flight-Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, 62" MXS Green, 62" Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51, Apprentice.

        Comment


        • It sounds like it could be voltage sag on one of the batteries causing an LVC to my ears, especially as downwind is prime wind shear territory if your airspeed is low (irrespective of your perceived ground speed).

          Comment


          • The43rdHammer As sad as it hurts to say, I'm inclined to agree.

            Hugh's aft-of-Book-CG is safe, as well, since that's where I tend to fly mine.
            Camp My Instagram @Alpha.Makes

            Comment


            • Very sorry to hear of Ben's disaster. This bird does need up elevator trim, even with the CG set right, so it may have needed a little more and that's something you can trim out of course, when you have the opportunity during the first flight. But it does sound to me as the battery failed (most likely one cell) which caused the ESC to shut down the EDF. The RX was probably still powering the servos but that bird will nose down fast if you shut down the power and the trim is slightly down.

              My best guess is that one cell was bad and it caused a voltage drop under load. When I check my 6-cell pack after a flight (I do this every time) usually all of the cells are very close to each other in terms of the voltage but when you notice one dropping a lot more than the others it can mean that one cell is going bad. It won't show up until you start discharging it under load. Its really terribly unfortunate that it did that to you.
              I fly: F4, A4, A10, F104, P38, P51D "Iron Ass", B24, Dauntless SBD, F7F Tigercat, Dynam B26 & P61, Lipp.P19, Durafly Komets, Vampire, Sea Vixen. A Radian XL...

              Lots of Rabid Models foamies, including my 8' B17 & 9' B36... and snot-powered planes including Mud Ducks! Marc at www.rabidmodels.com

              Comment


              • Thanks for the input guys.

                I don’t *think* I remained in control of the surfaces - ie I think I lost servo power. I would’ve eased the nose up a little to slow it down if possible. And yes, while I was downwind my ground speed would’ve been higher, I was near full throttle the whole time and definitely had plenty of airspeed - no where near a stall, even crashing! The nose down tendency just increased airspeed further.

                So....Quite possibly a battery issue?

                I’ll check the cells this am and see - but I guess the crash damage could have ruined that anyway.

                hugh - gosh no, please don’t feel bad!! Thank you for your help.

                I guess there’s not a way of doing much about it in returns of a claim (not to motion rc) but hobby king for the duff battery if it was bad?

                All I can compare to it, is the avanti. Flown in there plenty of times, no problems off the grass, takes off in a 1/5th of the Distance this wanted to.

                is there any chance the throttle wasn’t calibrated properly? It spooled up a little slowly but the power seemed ok.


                Ben

                Comment


                • Tough Ben...but we've all been there ! Currently "resurrecting" and old H9 Bluenose, bought the bits on line. I loved my first one but it went down hard about ten years back. Flying along nicely at 2/3 throttle but just tipped over into a spin for no apparent reason. Picked up the confetti in a bin bag swearing I'd give up the hobby!! Twenty planes later I'm worse that ever!! Good luck with the rebuild, this one is worth it !

                  nb. I was a bit low on power for grass as well but reset the Yep timing from auto to 18% and it made a huge difference to lifting off.

                  Comment


                  • BenAtkinsonUK

                    Originally posted by BenAtkinsonUK View Post

                    So....Quite possibly a battery issue?
                    That's certainly where I would start, but remember to test them under load, they'll likely look perfectly fine sat on the bench hooked up.

                    Maybe Alpha or another can advise, but I tend to put them in the model on a wattmeter and run them up to full power to see if it drops away significantly (some decline is perfectly normal, but if it's a gradual persistent decline in power then it's indicative of a chemistrey issue and you should consider replacing them).

                    Comment


                    • https://www.hobbysquawk.com/forum/rc...811#post265811

                      About crash F4

                      I read you used an As3x safe rcvr from Spectrum?
                      Do you have telemetry, so you can see you'rs rcvr voltage and rcvr signal from xmtr (rssi in taranis).
                      I can read out separate voltage of LIPO, all 6 cells so I can see if there is an issue.
                      I have read in other threads about brown outs in rcvr due to gyro.
                      They solved that by using a capacitor on a free servo output.
                      It's always a bummer when you loos a plane and you are searching for answers why it went down.

                      Hope you find yours issue.

                      Grts Hans

                      https://www.hobbysquawk.com/forum/rc...631#post265631

                      Comment


                      • Originally posted by locharrow View Post
                        Tough Ben...but we've all been there ! Currently "resurrecting" and old H9 Bluenose, bought the bits on line. I loved my first one but it went down hard about ten years back. Flying along nicely at 2/3 throttle but just tipped over into a spin for no apparent reason. Picked up the confetti in a bin bag swearing I'd give up the hobby!! Twenty planes later I'm worse that ever!! Good luck with the rebuild, this one is worth it !

                        nb. I was a bit low on power for grass as well but reset the Yep timing from auto to 18% and it made a huge difference to lifting off.
                        Oh interesting - how would I do that??
                        Definitely felt lacking in power - felt heavy in the air (partly due to nose heavy) but it just didnt seem like it flew nicely and fairly quickly, just how the videos and reviews show. Bit pig like so im inclined to think a power issue...whether thats a calibration or batter issue ....


                        Guys again - thanks for your inputs. Im just gutted I only got about 15 seconds i flying her.

                        I do have an ar636 receiver - and maybe it was a brown out - that was my first thought. I looked at telemetry but the battery disconnected and at that point I couldn't read how many frames I'd missed or if i had a brown out. I can't track battery voltage from it though.

                        I'll bench test the batteries under load this weekend...!

                        Any other thoughts welcome chaps...

                        Comment


                        • Some testing this am ....All tail servos, all wing servos and serfacts and board and rx still work...and in near perfect condition - it really was a NOSE dive.
                          Can barely look at the model still annoyingly. You know!|?

                          Anyway (help/suggestions appreciated)

                          My plan this weekend...

                          1. Test power train...
                          2. monitor batteries
                          3. asses what I want to do from there......

                          My options....
                          1. Repair the foam (would be a REAL bodge job...and look pretty terrible....in fact....bloody hilariously awful).
                          2. Buy the fuse only (hoping the transfers come with!) ...and see if I can repair the rest...
                          3. buy the ARF kit (expensive when I don't really know what caused it)

                          BUT....im in good spirits really chaps, there was a fairly bad accident at the airfield I fly 1:1 planes from ....I'd rather crash RC than my aircraft any day of the week.
                          (incidentally ....feel free to check out my channel...itll soften the blow if i gain a few subs lol)

                          What would you do in my shoes with the F4?

                          Ben

                          PS an example of one of my videos

                          https://youtu.be/ZAlPqapd7xM

                          Comment


                          • "Oh interesting - how would I do that??"

                            Well when I first installed the Yep in the plane the fan spooled up like a heli. I tried to manually reset it.... the "full throttle ...music..tones etc and it did work a lot better. After my unintended maiden I flew it a couple of times and it was sluggish to lift off but flew fine. I bought a Yep programming card and reset the timing to 18%...chalk and cheese, lifts off in 2/3 the distance at a higher speed.

                            If your rebuilding get a tub of Wonderfill filler, great stuff, when it's dry it wet sands to a great finish. Put squashed parts in hot water to expand the crushed foam cells ...helps a lot in some bits but not all.

                            Comment


                            • Ben, again sorry for the crash... As you can tell I'm a person of few words (unless someone shows their stupidity on here and NO you haven't)...

                              Your "complete loss of power" still resonates with me as a loss of radio signal. If I'm wrong tell me.

                              That means it wasn't radio set up (Hugh) or balance or something like that though when the power shut off nose heavy glides worse. That you lost motor and radio control is important. If the ESC went bad you would have lost motor power but retained radio control.

                              That tells me you need to find out why you lost radio control. Did you loose the link between transmitter and receiver or did you loose power to the receiver.

                              Thinking about the link don't assume that because everything worked fine in another airplane or that it passed a simple range check that it wasn't a radio issue. depending on antennae placement, redundancy (if Spektrum protocol of DSM2 or DSMX) or other factors what works okay right now and here may not work okay over there 30 seconds from now.

                              If it was a power issue was it a short term glitch, brown out or something or was it a long term problem, bad BEC, bad battery, bad wire, bad solder joint, loose wire.


                              If it was me before I think about rebuilding (and I would rebuild) I would do enough testing to prove to me that it won't happen again. If I couldn't do that I would test fly the components in something expendable a whole bunch of times to prove to myself it's worth my trust and even then I'd be thinking of another receiver/ satellite, BEC, and maybe ESC (though they are separate in the Phantom).

                              I hope that helps you think about some possibilities and where to look for issues. Good luck!


                              Oh and I say it a lot... Always calibrate throttles when you build a new plane or if changing setup, receiver or ESC. Always check balance when you first build or modify the aircraft or use different batteries, never assume a balance, check it. Always range check your plane when new or if you have changed or moved any radio component, it's not a bad thing to randomly recheck it every week or now and then too.

                              Comment


                              • Originally posted by BenAtkinsonUK View Post

                                Oh interesting - how would I do that??
                                Definitely felt lacking in power - felt heavy in the air (partly due to nose heavy) but it just didnt seem like it flew nicely and fairly quickly, just how the videos and reviews show. Bit pig like so im inclined to think a power issue...whether thats a calibration or batter issue ....


                                Guys again - thanks for your inputs. Im just gutted I only got about 15 seconds i flying her.

                                I do have an ar636 receiver - and maybe it was a brown out - that was my first thought. I looked at telemetry but the battery disconnected and at that point I couldn't read how many frames I'd missed or if i had a brown out. I can't track battery voltage from it though.

                                I'll bench test the batteries under load this weekend...!

                                Any other thoughts welcome chaps...
                                Ben, when testing the battery, charge it fully, then put it under load hooked up to the ESC and EDF of the F-4. Simulate a full 3 minute flight, starting at full throttle for some time, reducing it to 65% for a while, and occasionally back to full throttle as if you're doing a cuban 8 or split S. I had a couple of batteries that a cell went bad. It charged fine, all cells charge to 4.2 volts. Initial thrust was good, then after about 15 seconds on full, it dropped off incredibly. Reducing throttle to 25% and it was OK, then back to full at OK for about 4 seconds, then dropped. After disconnecting it, 1 cell was down about 25% from the others, but after 30 seconds all cells were back to being close, so it was a sneaky little bugger. Had 2 that did the exact thing and unless I bench tested it for a full flight, I wouldn't have been able to figure it out.

                                Although I'm still betting on a brown out, but the only clue that it may have been the battery is the slow take-off and slow climb. Even on grass that's about 1" and wet, mine accelerates fine and after take-off I have to be careful that I don't let it climb too fast or too high, and yours did not do that. I've had 2 brownouts (both with the same jet) but that was due to my numskull placement of the main antennae and active end completely alongside the battery. The signal was intermittent, which allowed me to retain some servo control and ended up with a hard landing, but still better than a dive into the ground, so those were a little different than yours.
                                Hugh "Wildman" Wiedman
                                Hangar: FlightLine-90mm F18 Canadian Demo, F16 Wild Weasel, F4 Phantom, F4 Blue Angel, 1600mm Corsair & Spitfire, Olive & Silver B-24, Stinger 90, Red 80mm Avanti. Extreme Flight-Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, 62" MXS Green, 62" Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51, Apprentice.

                                Comment


                                • Originally posted by locharrow View Post
                                  "Oh interesting - how would I do that??"

                                  Well when I first installed the Yep in the plane the fan spooled up like a heli. I tried to manually reset it.... the "full throttle ...music..tones etc and it did work a lot better. After my unintended maiden I flew it a couple of times and it was sluggish to lift off but flew fine. I bought a Yep programming card and reset the timing to 18%...chalk and cheese, lifts off in 2/3 the distance at a higher speed.

                                  If your rebuilding get a tub of Wonderfill filler, great stuff, when it's dry it wet sands to a great finish. Put squashed parts in hot water to expand the crushed foam cells ...helps a lot in some bits but not all.
                                  Sorry what's a YEP? Because it DID spool up like a heli actually - and your description mates the take off etc. Not saying thats the issue with the crash but going forward I think I had your issue too...sluggish!

                                  Comment


                                  • And Evan, Hugh....

                                    I've just spoken to the chaps who witnessed it (we fly from my mates grass full size runway in the UK), his dad was there - a 777 BA captain, and his mate - former Vulcan pilot who....they all saw it !!! But interesting they said it DEFINITELY regained power before impact. SO....maybe 3 seconds of no control whatsoever (no servos ....I couldn't use the elevator at all) ...then it came back.

                                    I'm inclined to think brown out still too. I'll get testing later today on the ESC / Power system / battery.
                                    They are brand new Hobby King ZIPPY 6200's (40C).

                                    But yes - slow to rotate - looked more like the videos I've seen of the 90mm F16 on grass rather than the avanti i know well. I wasn't expecting avanti performance but this certainly wasn't right. I Was going to land straight away and sus it out ....but then we know what happened next.

                                    Evan, yes - could be a thousand things if its a radio issue (not necessarily brown out as you say.)
                                    Hugh, I'll report back on battery testing.

                                    Everyones help with be HUGELY appreciated and valued - so please do check back and see if you can help - SUPER thankful.

                                    I WILL get to the bottom of this.......was always a real ambition to have a super scale jet (hence why I'm reluctant to fix what I have ...want it looking super duper! But we'll see)

                                    Ben

                                    Comment


                                    • A YEP 150 esc and a Freewing 12 blade 1853 kV is what I use in the F4.. evidently the esc is programmed from new for heli's,hence the slow spool up- -- I don't know why auto timing failed to deliver power but 18% sure does!

                                      Comment


                                      • Originally posted by BenAtkinsonUK View Post
                                        And Evan, Hugh....

                                        I've just spoken to the chaps who witnessed it they all saw it !!! But interesting they said it DEFINITELY regained power before impact. SO....maybe 3 seconds of no control whatsoever (no servos ....I couldn't use the elevator at all) ...then it came back.

                                        I'm inclined to think brown out still too. I'll get testing later today on the ESC / Power system / battery.

                                        But yes - slow to rotate - looked more like the videos I've seen of the 90mm F16 on grass rather than the avanti i know well. I wasn't expecting avanti performance but this certainly wasn't right.

                                        Ben
                                        Another thought Ben. If you finally narrow it down to a brown out (starting to sound more likely), you may want to add a remote satellite carbon fuse receiver (Horizon product # SPM 9746 $39.99 with 24" extension) and locate it up in the front nose area where there is plenty of room. I've started adding those recently (Stinger 90, F-18, SU-30 and soon to come A-10) when Evan D and a few others suggested it for my F-18 after they saw photos of my AR 636 location. It's just for a little extra "life" insurance when I had 2 brown outs in my Stinger and since adding them, no problems and I can sleep a little more soundly. After your experience, I'm thinking I'll add one to each of my F-4's since we ended up with a very similar receiver set-up and there are a lot of electrical and power wires near the receiver which may have added to the issue, including the afterburner wiring. Just put 2 of them in my HH wishlist next time I order from them (which is not very often anymore after dealing with Motion RC the last several years).

                                        Regarding the poor initial take-off and climb issue, that's another potential issue. Just did a battery test on that "heavy" F-16 you mentioned and the SU-30 of mine with an HRB 6000 and the "brick" Hobbystar 8000 and if you see the "crappy" video I did on both, the take-off on grass for each was under 100 feet on the F-16 and just over that for the " double-decker UK bus" SU-30, even with the heavy 900g 8000 battery. The F-4 should do much better. If you have a power meter, the stock F-4 fan should draw somewhere between 118 Ah-122 Ah and 2750 Watts-2900 Watts from a good fully charged battery on initial full thrust. That's using a Roaring Top or HRB battery (I use the RT 6250 35C) and the Admiral 6000 is around 110 Ah and 2550 Watts, still enough to do just fine. Have never tested a Zippy, although noticed that they seem to puff easily from what others at the field have experienced.
                                        Hugh "Wildman" Wiedman
                                        Hangar: FlightLine-90mm F18 Canadian Demo, F16 Wild Weasel, F4 Phantom, F4 Blue Angel, 1600mm Corsair & Spitfire, Olive & Silver B-24, Stinger 90, Red 80mm Avanti. Extreme Flight-Slick 60, 60" Extra 300 V2, 62" MXS Heavy Metal, 62" MXS Green, 62" Demonstrator. FMS-1700mm P-51, Red Bull Corsair. E-Flite-70mm twin SU-30, Beast Bi-Plane 60", P2 Bi-Plane, P-51, Apprentice.

                                        Comment


                                        • I lost an A-10 and an F-4 from what appeared to act like a brown out. Then I discussed with a HAM radio guy. Since my P-38 never has had radio issues and two EDF jets did, he suggested the common mode RF interference from the ESC is the issue. This can cause the transmitter and receiver to lose handshake/binding and give what appears to be a brown out. I installed ferrite RF chokes on the input side and output side of a new F-4's ESC and mounted them as close to the ESC as possible. Results...after a huge number of flights with the RF chokes, I have never experienced this loss of control again. Use the largest ferrite choke you can fit on each wire separately is best but a single large choke with several wires running through it works too. Any filtering is better than no filtering.

                                          Reposting the below from a prior post a few months ago....

                                          Add some clip-on RF chokes to each of the power leads going to and coming from the ESC. These high-current ESCs can generate common mode radio interference which might interfere with the hand-shake between the transmitter and receiver. Any length of wire between the ESC and the RF choke is an RF radiator. So, keep the chokes as close to the ESC as possible. I lost two EDF jets due to a transmitter/receiver hand-shake loss. Since I've added the RF chokes to the bird #2, I've had ZERO radio issues with bird #2 and have flown bird #2 hundreds of times for over a year. Get the clip-on RF chokes from Amazon.
                                          Use these, and say goodbye to radio problems when flying EDF jets.

                                          -GG

                                          Comment

                                          Working...
                                          X