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Old Jul 30, 2007, 11:04 AM
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Alfa Mig 15 - Bad Maiden!

Tried to maiden my Alfa Mig 15 Saturday with the stock set up, MP Jet motor, jeti esc and 1320 TP. CG appeared alright with the 1320 forward as I could get it, right under the forward cockpit lip on top of the inlet tunnel. Hand launched level with full power, the Mig stood on it's tail, stalled and went in hard. Nose exploded, tail broke off, wings separated from fuse. Again, the cg and throws were per instructions. I have many years of rc experience with sport glow models, this was my first adventure into edf. Is this power setup marginal? Should the model be hand launched throttle off? Any suggestions or info appreciated, thanks!
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Old Jul 30, 2007, 11:34 AM
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Tehachapi ,CA.
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the mig some times stands on it's tail if to much elevator is used ,or the launch had too much AOA.you might of had too much up trim.if the C/G was right then it's just the way it was launched. sorry to hear about the plane
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Old Jul 30, 2007, 11:59 AM
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Thanks Air Sally, rather than try and repair, I'll probably just build another kit. Next time, I'll also get someone to hand launch it for me so I can concentrate on flying and not launching until I get acquainted with the flight manners.
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Old Jul 30, 2007, 12:00 PM
latinflyer
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United States, CA, Milpitas
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I have a alfa mig also, I launch first time full power with recomended CG dead on and elevator center(level) with no problems at all it went right up with no problems. I replaced motor for AON 4900KV Thrust series and at 21AMP no problems still it fly like a champ.

Latinflyer
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Old Jul 30, 2007, 02:06 PM
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hoghead385
sorry to hear are you sure that its not repairable?
Steve
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Old Jul 30, 2007, 02:29 PM
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Hoghead, sorry to hear about your bad luck. I wonder, did you do a glide test over some long grass first? I have to maiden my Mig soon, but I'm planning to do a glide test first.

What are other people doing? Going straight to a full power hand launch seems a bit risky to me.
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Old Jul 30, 2007, 02:46 PM
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Quote:
Originally Posted by Gerry__
Hoghead, sorry to hear about your bad luck. I wonder, did you do a glide test over some long grass first? I have to maiden my Mig soon, but I'm planning to do a glide test first.

What are other people doing? Going straight to a full power hand launch seems a bit risky to me.
Doing a power off glide test seems more risky to me. These things like a little speed to stay aloft.
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Old Jul 30, 2007, 03:16 PM
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No Steve, total loss. The Mig came back down nose first on our paved runway and disintegrated! The internals seem to be okay, but the foam shell exploded and broke in several places. The manual suggests doing test glides, but I did not perform any. I'll grab another kit and get to it, after reading all the posts on the Mig and F86 I want some air time!
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Old Jul 30, 2007, 03:31 PM
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Vintauri, even with a good toss, over long grass?
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Old Jul 30, 2007, 04:04 PM
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I had exactly the same thing happen with the first Alfa Sabre I built - and like you I questioned the CG but it was exactly where it said in the instructions, also the elevator was set neutral. The problem is that once it goes vertical with little forward speed shortly after a hand launch, these Alfa models are so fragile, repairs after this sort of incident are nearly impossible. These Alfa models do look great and fly well but they are still a great advert for proper built up models!!!!!
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Old Jul 30, 2007, 05:25 PM
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Cleveland, Ohio
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I had this Alfa Mig and luckily the first time I launched mine I had the CG to far aft and it ended up going up up and away( thankfully mine didnt stall out) and even after full down trim I had to bring her down with throttle managment. After I brought the batt all the way forward It flew great for many flights. I would buy another and had the same setup as yourself. Good luck...
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Old Jul 30, 2007, 06:42 PM
SaR
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Orlando, FL
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Sorry to hear about your mishap.

I always launch my F-86 underhanded at 3/4 throttle and have never had any problems.

I think full throttle thrust makes the the nose pitch-up too much for the model to recover at slow speeds.
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Old Jul 30, 2007, 07:03 PM
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Thanks for the info and encouragement guys! I've never seen an edf launched underhanded before. Does the launch require a slight push with throttle or a good heave??
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Old Jul 30, 2007, 07:32 PM
SaR
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Orlando, FL
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Check out the Alfa F-86 thread for a lot of good info...


Take a look at this video for a great example of how to launch underhanded:

http://www.rcgroups.com/forums/showt...30#post7203337

CN.....hope you don't mind me referencing your flight?

Kent
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Old Jul 30, 2007, 08:18 PM
Time is Hobby
Northern, NJ
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For maiden, I would always recommend ROG if your field grass is capable.
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