Electric Flair Magnatilla

[PatMc]

The CG is shown at 3.5" back from the LE, which is in line with the back of the mainspar on my plan.

[propogandhi]

Bad news I'm afraid. I was on the last turn into my approach this evening when I lost all control. The model wouldn't respond to any input I gave via the Tx, all control were just fixed at there last command input. I fear it was a classic 'brown out'. So with no real height to wait out the 5 seconds or so it takes relink she went in with a nose down banking angle.
 
Its really soured this couple of weeks I've had off work, but it can be rebuilt. I just didn't want to be rebuilding a model that I'd just finished and that flew so well and I liked so much. Plus I had other projects ready to start next week, but they'll have to be pushed back now too.
 
The fuzz was basically a right-off, the tail is complete and fine, the wing, having removed the covering, was found to have a broken spar and some split sheeting, but can be fixed. I'll look into ordering the ply parts for the fuzz next week, oh and a new cowl as well (this will be the 3rd!. The rear fuzz stringers can be made up from stock etc, I'm just glad I kept the plans and instructions. All electronics seem fine too although the force of the impact shattered both gears in the HS81 aileron servos rather surprisingly.

As mentioned it seem to be a classic case of brown out. The only thing is I never would have expected it on the Spektrum system. I was lead to believe that Spektrum 2.4 was glitch free. Any body else had 'brown out' issues? I'd be interested to know. It may well have been that the Rx pack was going flat. I have flown for so long without the need for a separate Rx pack, that I forgot to charge it recently, so it may well be that. I've lost my hitec battery checker though so can't be sure. All I do know is that the 4 cell 1200 Rx pack was at 5.19V when checked after the crash. Is this too low?
One other concern is that I got brown out last week for the first time ever with a smaller foam model with no Rx battery (it has BEC), plus in almost exactly the same place (on approach) and same attitude. So I wonder if there is some local 2.4 noise crossing the field at that particular spot, could this be a possible cause, does this happen with 2.4?


So just as I thought I'd brought this build tread to a close, it seems I'll be starting it back up again. But this time it will only be the fuzz so I hope to have the Maggy ready once again, by the end of the month.
 
Ok, I'm off to go through all the 'what if's' now in my head. Nice way to get to sleep


prop.

[David Ashby]

Oh dear, that's sad Stuart. Well tbh a flight pack should be charged at least before every session - a flat pack (which isn't a brown-out btw) may still be showing what seems like a good voltage. Charge it up and see how many amps it takes I guess, then you'll know for sure. I'd say it's unlikely to be interference as 2.4 just doesn't suffer from this (despite what some people would have you believe). Let us know.

[Danny Fenton]

Hi Prop,

That is sad news, I hope you get Maggy repaired real soon, and more importantly you get to the bottom of the radio problem?

 

I have been advised by those that have been doing this longer than me that you should go to 5 cells if you are on Nimhs as it doesn't take much to drop the voltage of a 4 cell pack. I have bought some Sanyo eneloop 5 cell packs from Overlander and they seem to handle the current much better than most.

 

Cheers

Danny

 

[Tim Mackey]

Mixed messages here about "classic brown outs" ...and glitches and "local 2.4 noise".

All these things are entirely different from one another - and you mention an uncharged radio battery was used also I think a proper diagnosis, and descritption of exactly the symptoms you suffered is needed here propi....

Very sorry to hear of the loss mate - it was lovely looker - but glad to hear that it is repairable. Keep us posted.

[propogandhi]

Morning gents, thanks for your kind words and info.
 
Yes its all a bit confusing. Im using the new AR6250 which has an extra LED that will flash if the signal is lost during flight. Well I checked the Rx after the crash and indeed it was flashing, which taking it from the instructions, means I lost signal (the RF link) and in my case I did not have enough time (or height) for the rx to reboot and relink to the Rx. Now if this where due to the Rx pack dipping below 3.5volts, then this would be 'brown out' wouldn't it?
 
But if it did dip, why? I was able to operate the servos again immediately after the crash. My pack is only a 4 cell pack, and although it was at 5.19volts (well above the 3.5Volts threshold) I admit I hadn't charged it for well over a week, so I'm guessing that is the what caused it. But I will know more when I can find my battery checker.
 
Also of note. The instructions list that the AR6250 has a fail safe feature, which moves the servos to the preset fail-safe positions, if the signal is lost. But this didn't happen, even though the signal was lost. Therefore I can only assume that this possible drop in Rx pack voltage, not only caused the signal to be lost, but also left insufficient power to move the servos to the neutral fail-safe position.
 
What do you guy's think? Going by my think above, it does in my mind point to a low battery on the Rx pack. The only problem with this is that I could operate the servo and the Rx after the crash, so the Rx pack didn't go completely dead.
 
Please jump in and guide my wondering mind gents, this is all purely speculative. But as it is, this will be how I'll present it to Horizon on Monday.
 
prop.

[propogandhi]

Whats left of her:

 

I'll use evering in this image in the new build except for the fuzz and firewall. I'll build a new one as soon as I can get the ply parts from Flair.

[propogandhi]

Bang goes the theory of the the flat Rx pack. I just found my Hitec 'battery mate' checker, it gave a reading of 80% full! In a way I wish it had have been flat, it would have made it an easy problem to fix. Now I havn't a clue as to what caused my lost of control/signal and I guess I'll need to before I fly it again

 

Any clues gents?

 

prop.

[David Ashby]

Hmm yes that doesn't help in the scheme of things prop, I'd still cycle the pack to really make sure it's holding charge though.

[Danny Fenton]

Prop, have a look at this thread, it made me realise a few things. I now use 5 cell Sanyo Eneloops. A friend tried discharging his new 2500 Nimh pack and the charger/discharger at just 1A and it shut down after just seconds. He bought a new Eneloop and the discharge cycle was fine. It seems the bigger the pack capacity the worse at delivering a high(ish) current, I guess the internal resistance goes up.

 

http://www.modelflying.co.uk/forums/postings.asp?th=12966&p=1

 

Cheers

Danny

[propogandhi]

Thanks guy's just to be safe I will use 5 cell quality packs from now on. But what about when it happens on models that use a BEC? Here's what happened this morning...

This morning whilst flying my Balsacraft Hurricane, it happened again. The hurricane has been fine up until now. It uses an AR500 and a BEC. The lipo was fresh from the charger and it had only been flying for two mins. Then the same thing happened. Signal loss, the throttle did shut down but I had no control at all! It didn't reboot in time to avoid hitting the ground. Luckily it rebooted just before it hit, so as I was holding full up elevator it managed to pull out of the dive. If I hadn't been hold in full up it would be in piece's now. As it is, there is only minimal damage.

But I think its wise for me to send the Tx off to be checked. This shouldn't be happening on 3 different models in less that a two week period (only one using a rx pack, the other two using BEC), having only flown say every other day of that 2 weeks. The Tx battery was 3/4 full BTW.

My only other thinking is that there is something locally that could be interfering with the signal/system. I noticed that in the spring a small wind turbine went up a few fields away. I wondering if that could have some kind of system on 2.4 ghz band too. But even still Spektrum should be able to filter this shouldn't it? Plus I had flown before whislt the wind turbine had been operating, before this 2 week period.

Either way I won't fly again until I find the route cause of this. I've already damaged too many models and I just don't have the confidence in it to fly until I know whats causing this.

Any ideas guy's? In any case on every occasion, I did loose control of the model, I had no signal, of that I'm sure. But the cause, what could it be? Do you gents think its worth sending the Tx back to Horizon Uk for checks?


Many thanks,

prop.

[Danny Fenton]

That doesn't sound very good Prop, how are you powering the Tx?

 

 

[Tim Mackey]

prop. You are confusing brown out / power loss with signal failure. There was ver y long running "discussion" about this some months back - the upshot is this.

If your servos went to the reset positions ( indicated by throttle closing as all the others actually do is hold "last known good" ) this is NOT brown out - its signal loss. By the very virtue that a brown out is actually nothing more than a momentary drop in supply voltrage below the minimum threshold ( circa 3.5V on the spekky stuff ) this power loss will in itself, create a situation where the servos cannot move - they have no power !

This is why I said earlier that it is vital that we have an accurate and full description of all the symptoms so that we may be able to distinguish between these two very different problems.

At a rough guess I would say yours is a signal problem not a power supply issue.

Why are you having a problem? Dunno... aerial orientation, faulty component, incorrect Rx installation ( any pictures of your installation ? ) broken aerial wire, etc etc.

When did you last do a full and proper range check - holding the model at all 4 angles to the Tx ?

[propogandhi]

Just reading through my old thread. I completely forgot to post an update. The replacement parts from flair got lost in the post so I had to wait an entire month before they would send them out again. But the Maggy has now been fully rebuilt and up and running since the end of the summer and flying just as well as she did before.
 
Also regarding the radio problems, I returned the DX7 to Horizon for testing and it proved to have a fault RF board. They didn't have a spare board at the time so they sent me out a brand new DX7 free of charge. Great chaps at Horizon. With the replacement Tx I haven't had a problem since, but to be on the safe side I now fit all my bigger models with 5 cell rx packs and use voltage protectors on EVERY model.
 
I'll be sure to bring her to a few more fly-in this year, the first being Bickley in May so I hope to see some of you then.
 
 
prop.

[Stephen Grigg]

Have you any photos of the rebuilt model,heres mine rebuilt for a second time,it seems to like trees

[propogandhi]

Just think of the before pictures but now with an added pilot. As I used new cnc parts from flair, its identical to the original.

 

 

nice job on yours BTW. I like the chrome plate cockpit.

 

 

prop.

[Richard Wood]

Glad you got your Magnatilla flying again prop.

It was too young for a black bin bag!

 

Richard

 

[john saunders]

HI ALL.

I am just finising my magnatilla, i have made the nose 20 mm. longer.

I am fitting asp 52 four stroke so will have to see how it flys.

 

[Olly Giles]

Maggy's never die! I learnt to fly on mine 7 years ago. It was built for me by my grandad in red and linin solartex. After about 2 years i took it on holiday to my uncle's farm. while there i stored it in a barn where we were having a BBQ outside after a few beers and plenty of burgers we went inside only for my auntie to say "can you smell burning plastic?". The wing made perfect kindleing but the fusalarged survived specked with bitchumin from the melted roof. After re covering the fusalarge and being given my granpa's wing from his maggy i flew it for a bit longer until i flew it into the back of a horse. The horse was fine but the model had a big dent in the cowl. After the horse incedent i gave it back to my grandpa and he flew it for a couple of years and then stored it. After having the engine in a mini hype for the time it was in grandpa's possetion we aquired it back about a year ago and put the irvine 39 back in. I have been flying it ever since. But this being my maggie it wasnt long until it attracted another incedent; a mid air collision with a PZ corsair that was chopped into confetti but left prop cut marks across the wings and tail, sliceing some of the formers and leaving another dent in the cowl. But maggie never dies i flew her in 30mph winds today and i intednd to until she falls apart.

[propogandhi]

Blast from the past, but just as an FYI, I got hold of another Magnatilla, this time glow powered and have started the restoration process. You can find out more below:

[leccyflyer]

Hi Stuart

Happy birthday mate - shame that you didn't get the model to fly on your birthday, but you are doing the right thing with a full restoration to full health. I remember your previous Magnatilla, which flew so well at the fly-ins back in the day.

Really enjoyed your video - like you I love a second hand airframe, though sometimes they do take quite a bit of fettling. I'll have to see whether I can get my Magnatilla up and running in tandem with yours, but of course she's electric.

Cheers

Brian

[propogandhi]

Hi Brian, good to hear from you, its been a long time since I've posted anything either here on RCG, nice to talk to a familiar user. Glad you liked the video, as this is now going to be glow powered, I guess I could always start a new thread or post into one of the rolling ones?

prop.

[Danny Fenton]

Good to see you posting again Stuart P.S. and I enjoyed the video, I try not to buy second hand, always more work making the model what you want than building another

Will enjoy following along.

Cheers

Danny

[propogandhi]

Hi Danny, yes for sure its hit and miss, but I've mostly enjoyed hits to be fair. But never mind, its making for a nice project and will be as I like it when done

Prop.

[timber007]

HI.

     I just brought a Magnattica mk2, but it does not have any plans or instructions. Is there anyone out that will sale me you old ones?

 

Thanks Tony