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Official Freewing MiG-29 Fulcrum Twin 80mm Thread
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Hey I got a little story. I wonder what GliderGuy will think since he flies so much. I made a stupid mistake, and I hope this won't happen to anyone else. I don't know how I did it, but it wasn't really that hard to do.
So I had the MIG at the field today and only got two flights in, because I was helping many other guys with their planes. Beautiful spring day in the mid 50's and very light wind.
During my second flight later in the afternoon I noticed a slightly strange noise like an odd whistle kind of noise coming from the ducts. But everything seemed ok so I kept going... but I was paying close attention. It noticed that it seemed to make the noise when I was going fast.
Towards the end of the flight it seemed kind of sluggish and when I came around a turn it seemed to be yawing... and slowing down... something was wrong.
So I gave it more power and came in to land. Normal procedure - slowing down, flaps down on the final base turn, come down the chute....and then I managed a fairly decent landing on the side of the runway in the grass (by then I was aware something was wrong but didn't know what... and was quite relieved to get it down in one piece.
So I brought the model back to the pits and started looking at it, ran the fans up just to activate both motors to see if something was in the ducts. Everything was working... I noticed a blade of grass in one fan..... but then I noticed that the other fan stopped turning!
So I cut the throttle and tried again. Both fans started, then one stopped after a few seconds. So only one EDF was working!
The sound was because one EDF was windmilling during the flight, I was flying on only one motor! I was amazed because the model actually flew pretty well!
I mean, thinking back, its pretty amazing that it handled so well with only one fan working. Well enough that I couldn't really tell what was going on. The yaw in the final turn gave it away.
So I am scratching my head and I assumed that maybe one of the ESCs had gone bad.
Next step was to take the batteries out and I tested them.
First battery was at around 27% remaining.
The other battery was at 1%. OMG.
I use RoaringTops 6250s and the battery wasn't puffed or hot. Just dead as a brick. The cells were down to about 3.1 volts!!
So what happened was that after the first flight the used batteries were sitting on the table. Later on when I loaded up the batteries for the second flight somehow I accidentally picked up one of the used batteries that were still sitting there from the first flight.
Off I went... I had power for about a minute and then it went dead.
Now it was only complete dumb luck that the dead battery was NOT the one plugged into the BEC powering the receiver! The good battery had that duty and the dead one was only plugged into the other motor.
I think if it were the other way around, the plane would have gone stone dead halfway into the flight (the BEC would have cut the power to the motor first, but who knows) and then I would have a tale of the plane not responding to the elevator, who knows.
As it was, I was able to pull this beast around the air with only one fan working.
The dead battery is on the charger now (carefully at 1 amp) and it seems to be charging back up.
Hope no one else ever has this happen! Flying this big plane on one fan is not recommended, 2 stars would not do again!
A friend gave me a good suggestion, I am going to use a sharpie and number my 6S batteries so I'll use #1 and #2 first, then 3 and 4, etc. That way I'll be able to avoid this aain!Marc flies FW & FL: AL37, MiG-29, T45,F4, A4, A10, F104 70 and 90, P38, Dauntless SBD, Corsair, B17, B24, B26 & P61, Lipp.P19, ME262, Komets, Vampire, SeaVixen, FMS Tigercat, FOX Glider & Radian XL.
Rabid Models foamies, including my 8' B17 & 9' B36... and my Mud Ducks! www.rabidmodels.com
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Originally posted by themudduck View PostHey I got a little story. I made a stupid mistake, and I hope this won't happen to anyone else. I don't know how I did it, but it wasn't really that hard to do.
Hope no one else ever has this happen! Flying this big plane on one fan is not recommended, 2 stars would not do again!
A friend gave me a good suggestion, I am going to use a sharpie and number my 6S batteries so I'll use #1 and #2 first, then 3 and 4, etc. That way I'll be able to avoid this aain!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 themudduck View PostThe cells were down to about 3.1 volts!!
Now it was only complete dumb luck that the dead battery was NOT the one plugged into the BEC powering the receiver! The good battery had that duty and the dead one was only plugged into the other motor.
I think if it were the other way around, the plane would have gone stone dead halfway into the flight (the BEC would have cut the power to the motor first, but who knows) and then I would have a tale of the plane not responding to the elevator, who knows.
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Glad you got it back OK, and good to hear it will fly on one fan. And yes, I've done it too (in my Mig-21). Now I have 3D printed caps that fit on the EC5 connector. I have 3 colors; green, yellow and red. Green is for charged, Yellow is for storage charged, and Red is for discharged. As soon as I take batts out of my plane, I put the red cap on them to ensure I don't accidently pick them up and put them back in thinking they are charged.
Pat
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Originally posted by crxmanpat View PostNow I have 3D printed caps that fit on the EC5 connector. I have 3 colors; green, yellow and red. Green is for charged, Yellow is for storage charged, and Red is for discharged. As soon as I take batts out of my plane, I put the red cap on them to ensure I don't accidently pick them up and put them back in thinking they are charged.
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I use numbered batteries (mostly to keep track of their number of cycles and know if one is bad, which one it is, etc), and even then you can make that mistake. It's not that I have yet... but I've found myself pretty close to doing it a few times.
And may have taken off with a used batt on a single-batt plane too, lol...
Point is, the mistake is almost always made when you are talking with others at the same time you are prepping the flight.
Not to say you gotta be rude and send your buddies away when preparing for a flight (or maybe yes) but to be self-conscious that it is a huge distracting factor and to remember to triple-check things in that kind of scenarios. Also one thing I often do is to touch batteries before closing the canopy. If one is warm, I know I messed up, wouldn't be the first time :)
As for the MiG flying acceptably well on just one fan, that's great to know, and bet it's mostly due to the fact that the nozzles are canted outwards (This reduces their yawing moment around CG).
BTW, already repaired the 'loose leg' and flew 3 more flights with the MiG today with some air to air footage.
I couldn't take it away from the fuselage without making a huge mess so I ended up gluing it in place and adding a balsa wood square strip to distribute the loads and block the thing in place. Ended up using epoxy... may regret later but so far so good. :)
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Originally posted by themudduck View PostHey I got a little story. I wonder what GliderGuy will think since he flies so much. I made a stupid mistake, and I hope this won't happen to anyone else. I don't know how I did it, but it wasn't really that hard to do.
So I had the MIG at the field today and only got two flights in, because I was helping many other guys with their planes. Beautiful spring day in the mid 50's and very light wind.
During my second flight later in the afternoon I noticed a slightly strange noise like an odd whistle kind of noise coming from the ducts. But everything seemed ok so I kept going... but I was paying close attention. It noticed that it seemed to make the noise when I was going fast.
Towards the end of the flight it seemed kind of sluggish and when I came around a turn it seemed to be yawing... and slowing down... something was wrong.
So I gave it more power and came in to land. Normal procedure - slowing down, flaps down on the final base turn, come down the chute....and then I managed a fairly decent landing on the side of the runway in the grass (by then I was aware something was wrong but didn't know what... and was quite relieved to get it down in one piece.
So I brought the model back to the pits and started looking at it, ran the fans up just to activate both motors to see if something was in the ducts. Everything was working... I noticed a blade of grass in one fan..... but then I noticed that the other fan stopped turning!
So I cut the throttle and tried again. Both fans started, then one stopped after a few seconds. So only one EDF was working!
The sound was because one EDF was windmilling during the flight, I was flying on only one motor! I was amazed because the model actually flew pretty well!
I mean, thinking back, its pretty amazing that it handled so well with only one fan working. Well enough that I couldn't really tell what was going on. The yaw in the final turn gave it away.
So I am scratching my head and I assumed that maybe one of the ESCs had gone bad.
Next step was to take the batteries out and I tested them.
First battery was at around 27% remaining.
The other battery was at 1%. OMG.
I use RoaringTops 6250s and the battery wasn't puffed or hot. Just dead as a brick. The cells were down to about 3.1 volts!!
So what happened was that after the first flight the used batteries were sitting on the table. Later on when I loaded up the batteries for the second flight somehow I accidentally picked up one of the used batteries that were still sitting there from the first flight.
Off I went... I had power for about a minute and then it went dead.
Now it was only complete dumb luck that the dead battery was NOT the one plugged into the BEC powering the receiver! The good battery had that duty and the dead one was only plugged into the other motor.
I think if it were the other way around, the plane would have gone stone dead halfway into the flight (the BEC would have cut the power to the motor first, but who knows) and then I would have a tale of the plane not responding to the elevator, who knows.
As it was, I was able to pull this beast around the air with only one fan working.
The dead battery is on the charger now (carefully at 1 amp) and it seems to be charging back up.
Hope no one else ever has this happen! Flying this big plane on one fan is not recommended, 2 stars would not do again!
A friend gave me a good suggestion, I am going to use a sharpie and number my 6S batteries so I'll use #1 and #2 first, then 3 and 4, etc. That way I'll be able to avoid this aain!
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TMD - Glad she got down safely!
Lots of good ideas presented here. Numbered batteries are good, stickers help....but I do one more thing for added assurance.....used batteries ALWAYS go in one location (my truck’s floor) and full batteries ALWAYS go somewhere other than the floor...,Ex: the dash or the center console, the seats, etc. Used batteries ALWAYS are put in one location ONLY. LOL and if I get to visiting, I do not hesitate to put the battery checker to good use.
When I am in the cockpit, and a distraction happens, RED FLAGS of mental alertness start waving. Checklists are re-done, etc.
-GG
And....yes, I have done this same mistake, too. P-38 and she survived.
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BTW, already repaired the 'loose leg' and flew 3 more flights with the MiG today with some air to air footage.
I couldn't take it away from the fuselage without making a huge mess so I ended up gluing it in place and adding a balsa wood square strip to distribute the loads and block the thing in place. Ended up using epoxy... may regret later but so far so good. :)
Hint: For all.... I got a scratch in my MiG’s canopy. I was able to take it out with a Mr Clean Magic Eraser....which is a VERY fine abrasive. Took a lot of effort and time (always work in circles), but the scratch came out, and no haze was added to the canopy. A final application of a good polish, and it looks like new.
-GG
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Thanks guys, appreciate the comments.
XViper is certainly right, the BEC would have kept working since that big battery pack has far more that 6 volts even when its fully discharged. So in either harness position (BEC or non-BEC side) the same result would have happened (one motor stopped working).
I do check the batteries right before I install them. Usually one battery is slightly higher than the other one and that one goes to the BEC side of the harness.
Anyway I did check the new batteries (the second set) before the flight, but both sets of batteries were sitting on the table and somehow I grabbed one of the used ones when I was sticking them in.
Like DCorsair said, doing a final voltage check after the newly installed batteries are sitting in the plane, right before going up, will be a great habit to get into.
And GG I'll make sure that the used ones never are placed near the good ones next time! There's no way to tell how "full" they are by looking at them, of course! Wouldn't it be nice if you could!Marc flies FW & FL: AL37, MiG-29, T45,F4, A4, A10, F104 70 and 90, P38, Dauntless SBD, Corsair, B17, B24, B26 & P61, Lipp.P19, ME262, Komets, Vampire, SeaVixen, FMS Tigercat, FOX Glider & Radian XL.
Rabid Models foamies, including my 8' B17 & 9' B36... and my Mud Ducks! www.rabidmodels.com
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Originally posted by GliderGuy View Postbut I do one more thing for added assurance.....used batteries ALWAYS go in one location (my truck’s floor) and full batteries ALWAYS go somewhere other than the floor.
Bring them in a sort of briefcase and all spent ones I leave in the outside so they cool down and far away from the rest in case one decided to go poof!
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Originally posted by Airguardian View Post
Yep... do that too.
Bring them in a sort of briefcase and all spent ones I leave in the outside so they cool down and far away from the rest in case one decided to go poof!
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 themudduck View PostHope no one else ever has this happen!
And since I have my batteries running parallel to share the current load, I also test with a cell checker before plugging them in.
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Originally posted by DCORSAIR View Post
It happens to all of us, stickers are a good idea, but one way is the best that it don't happen again, lay them in the jet or plane and check them with your battery checker before or after you strap them in.......
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Pretty slick! Tiny, too. 2cmx1cmx0.2cm
Link follows....ordered some!
https://www.amazon.com/dp/B06Y6JM98R...V0PQ7GJVGJAB39
-GG
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Originally posted by GliderGuy View PostPretty slick! Tiny, too. 2cmx1cmx0.2cm
Link follows....ordered some!
https://www.amazon.com/dp/B06Y6JM98R...V0PQ7GJVGJAB39
-GG
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