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May 06, 2019, 12:20 PM
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Thank you guys for nice words.

Phantom, I have always wondered why all Mig models are with red stars only. (Former) Czechoslovakia operated maybe 500 Mig-15 but only a handful were other than just aluminum+markings, you may want to see the link for kits at post #38.

One afterthought - does aluminium paint impair 2.4GHz reception? Would not it be better to use "carbon friendly" Rx and route antennas out of the fuse?

Thanks, Jan
Last edited by DingoII; May 07, 2019 at 02:28 PM. Reason: typo
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May 06, 2019, 02:49 PM
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Your Mig is fantastic puts my builds quality to shame.
May 06, 2019, 07:10 PM
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Quote:
Originally Posted by DingoII
One afterthought - does aluminium paint impair 2.4GHz reception? Would not it be better to use "carbon friendly" Rx and route antennas out of the fuse?
Jan, I have friends that have models with silver paint and some that have silver film also. I doubt the silver paint will be a problem.
To be be safe though, I recommend a range check with the airplane held in different positions. I would also do a range check with the motor running as well.

This reminds me, a friend had a small silver Eurofighter years ago that had reception issues but it was not due to the paint. The space for the ESC, receiver, and battery was very cramped. He had placed the ESC and receiver side by side and the EMF from the ESC was swamping the receiver.
Last edited by phantomphan; May 06, 2019 at 07:17 PM.
May 07, 2019, 01:59 PM
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Quote:
Originally Posted by tubalan
Your Mig is fantastic puts my builds quality to shame.
Thank you. I would say the same about your Lightning. I admire the well thought-over designs as is yours.

In fact, the Mig is my first "serious attempt in something else than a sailplane" after 20 or so years (I did a lot of free flight scale back then), and my first EDF ever so have been quite surprised it can fly. Still learning .

Jan
May 07, 2019, 02:13 PM
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Quote:
Originally Posted by phantomphan
Jan, I have friends that have models with silver paint and some that have silver film also. I doubt the silver paint will be a problem.
To be be safe though, I recommend a range check with the airplane held in different positions. I would also do a range check with the motor running as well.
Thank you, Phantomphan, I will do the check with the motor on. I am travelling now, will be back in 2 weeks or so, I report back then.

Thanks, Jan
May 26, 2019, 01:59 PM
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I re-maidened the Mig this weekend, no problem with the reception at all.

After 3 minutes power-on I recharged only 1100 mAh. The Hacker motor is heavy but seems to be quite efficient. For another flight I set the Tx timer to 4 minutes, the flight was Ok but the ESC got too hot for my liking. Any idea, please, how to get air to it?

I am very happy with the Mig, she can do everything I dare do, the hand launch is not a problem, after having added sand paper pads under wings, even thermalled her for 2-3 circles.

Jan
May 26, 2019, 07:40 PM
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Looks nice. I don't care for ESCs in the exhaust ducting, where avoiding the losses justifies a higher rated, heavier ESC which doesn't get hot without being in the ducting. There's also shorter battery cables and not having to add caps in some cases, which shaves weight. Haven't had a failure as of yet, but most are running at maybe 60% rating doesn't heat up much. Exposing the ESC to some air with a cutout in the intake wall has proven adequate. One brand that I have pushed without issue is the Castle, which uses quality fets. Used the 6A, 9A, 10A, 18A, and 25A all in apps with little to no cooling and running 2 inrunners on 1 ESC. The P25 running at 25A in the fuselage was possibly the hardest pushed. As for heat, I became convinced that the difference in fet quality mattered, when I accidentally killed a 9 or 10A Castle unit a 15A on the bench. The fets never failed. The solder got so hot that they slid off the pcb. After passing that test, I imagine they can survive a bit of heat.
Jun 03, 2019, 01:57 PM
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OK guys, I joined the "crash club" this Sunday. The Mig is under repair now, one dent in the leading edge and broken tailplane, the worst thing seems to be a lost link between elevator servo and surface, likely will have to cut the vertical fin open, which I really hate to do , and inspect/repair.

I would like to ask you for your opinion on the possible cause. The video below is from our local altimeter competition but the Mig occupies a fair portion of the footage. Following the launch (about 1:25) the model just went into a loop despite full down elevator. It hit the camera man, fortunately with no physical hurt to him. Also, during a previous flight I observed the same loop when flying slow at quite high AoA, when full power was applied the Mig just flipped on its back. Fortunately, I was able to reduce power, let it pick up some speed and pulled up still some 2 m above grass. Except this the Mig is a sweet flyer.

I suspected the line of thrust may have been directed up but it seems to be straight. Any idea, please?

Soutěžička Manušice 2 6 2019 (2 min 45 sec)


Thanks, Jan
Jun 03, 2019, 02:01 PM
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Sorry, double post
Jun 03, 2019, 03:24 PM
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Looks like batteries shifted at launch..aft CG
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Jun 03, 2019, 05:44 PM
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Mig 15's are noted to pitch up on too steep of a launch . Brent had a alfa Mig15 and it did that ...too much AOA when full power is applied ...was it destroyed? it sure flew nice and sounded cool when coasting by .
Jun 04, 2019, 01:57 PM
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Thanks for suggestions, guys. The battery stayed in place, I am sure of that. I observed this behaviour previously, and suspect it has something to do with the swept wing in combination with the center of gravity above the thrust line.

I hope to have the Mig in the air again by weekend and want to make several in flight tests, will report back then. It is an exciting hobby, isn't it?

As a side effect, I also discarded plans for building another swept wing model, I do not think I will ever go transsonic , so goodby my already shortlisted Mystere, Mig-19 and Su-7, will look for more traditional planforms.

Jan
Jun 04, 2019, 04:03 PM
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Good looking Mig.
Model below has about the best glide of anything I've ever flown. Similar to a Mig15. Not nose heavy at all, but move the CG rearward a small amount and it will loop on launch, pretty much just like in your video. Had a lucky save. The stab is smaller which narrows the CG range, but it was still further forward than expected and does not like being moved aft much at all. The battery mounts high but doesn't seem to cause any issues. Actually one of my favorite models to fly.
Jun 04, 2019, 05:56 PM
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AIR SALLY's Avatar
just make sure to make a level throw on launch . too high a AOA the wing blanks air to the stab .
Jun 04, 2019, 06:53 PM
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Yea my old Alfa Huck did that also ..was worse with low thrust line
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