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Messed up; advice and encouragement required.


Kohen

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So after everyone helped to fix my peg on the weekend I'm working form home today and messed up by popping out for a short session this morning to make the most of the sunshine. 

I dont know how I did it, I was tweeking my mixes and somehow I seem to have deleted and elevator mix without realizing untill I did a soft launch. It might have been soft but it immediately lawn darted. I put flaps and and tried to correct but i mist have been going too fast or something idk it didn't seem to respond. Anyway. 

Both wings are damaged where they mount to the fuse with the left wing having a delam at the root. The fuse has a crack in the saddle and a fractured boom just behind the back of the saddle. The wing joiner is also cracked. 

I dont know how I will manage repairing it. I can do it for sure, but dont know how close to 100% it will be  afterwards. Looking over these pics it feels like a write off. Would be interested to hear peoples thoughts re repair etc. 

20210907_104925.thumb.jpg.309af696864be1d645e988a54a2b8483.jpg20210907_105002.thumb.jpg.f268c56e8964cf55aa9f88537353efa3.jpg20210907_120252.thumb.jpg.8ecab829f7088221e666f10bde2f3b00.jpg20210907_120412.thumb.jpg.3e9020e3194c88a0ccf4984b2549ada3.jpg20210907_105748.thumb.jpg.16e5de2480b3901c6357198bda7ddea6.jpg20210907_105210.thumb.jpg.53991936ace495ade54d390362083705.jpg20210907_111539.thumb.jpg.e3f45d4270e2288e3db8805e467f78b1.jpg

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These models are very repairable!

Take heart in repairs here:

and here:

The fuse cracks can be glued (once aligned properly) with thin CA in the cracks, then I've used some unidirectional tape to reinforce the outside (as you'll see in the threads linked above).

I use this one: https://www.easycomposites.co.uk/80g-15mm-carbon-fibre-spread-tow-ribbon

along with their laminating resin: https://www.easycomposites.co.uk/el2-epoxy-laminating-resin

As for the repairs around the wing bolts - not sure. You might try posting in the BAMF2 thread on rcgroups - you'll get info from a lot more BAMF2 pilots and maybe Thomas might be able to chip in with something useful.

 

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Oh no, sorry Kohen.  All repairable (except I'd get a new wing joiner).  It wont be 'as new' anymore, but will fly just as well.  A good lesson to check surfaces are actually moving, not just a stick waggle.  

Do as Paul suggested.  Take your time.  The key to getting it right is preparation.  Don't rush it.  Will require multiple sessions as it will need to be done a sequence.

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Thanks guys. Yeah this ones going to take some time for sure. 

Ive messaged Thomas so will see if he gets back to me with any advice, but yeah ill post on rc groups and ask them for suggestions. 

Will order a new joiner for sure. 

I ordered some thin ca and I have tow and some light spread tow. I have fixed booms before so think i will be ok there. Definitely the wing mount area is what im most conserned about. And im hoping the inner sleeve part of the spar joiner isnt cracked its hard to tell atm. That wil be a tricky one to repair if it's broken. 

I have some z poxy finishing resin, think that's comparable to el2? 

 

 

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A shame for sure, but eventually happens to everyone.  I remember feeling the same when my NXT looped into the ground off launch.

It's still flying now and they are always nearly repairable.  Good learning exercise too.

I guess you need a spare model now so you can keep flying in the nice weather 😀. Good excuse.

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54 minutes ago, Kohen said:

I have some z poxy finishing resin, think that's comparable to el2? 

As a relative newcomer to carbon repairs, I haven't used the Z-poxy finishing resin. I've been very happy with the results from the EL2, but can't really compare.
Having tried to repair using tow, the uni-tape is a revelation! It just holds together so nicely (and flat). 

If the spread tow you have is similar then that might be just as convenient.

 

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2 hours ago, cirrusRC said:

A shame for sure, but eventually happens to everyone.  I remember feeling the same when my NXT looped into the ground off launch.

It's still flying now and they are always nearly repairable.  Good learning exercise too.

I guess you need a spare model now so you can keep flying in the nice weather 😀. Good excuse.

Ha yeah I have had breakages before but never anything this bad. Indeed repairing skills are ones hard learned eh. I do have a spare model but its a cheap one and like being in the dark ages compared to a bamf 2. So yeahhh... We'll see. 

 

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2 hours ago, PaulR said:

As a relative newcomer to carbon repairs, I haven't used the Z-poxy finishing resin. I've been very happy with the results from the EL2, but can't really compare.
Having tried to repair using tow, the uni-tape is a revelation! It just holds together so nicely (and flat). 

If the spread tow you have is similar then that might be just as convenient.

 

Cheera Paul. Hmm yeah ive definitely got the kind if tow that goes everywhere you dont want it to go. Ill have a look for the uni tape. Did you get that from easy composites?

Ive ordered some of that milled carbon strands from them; to put in the resin for repairing where its torn up around the wing bolts. 

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So, I did similar things not long after getting my first carbon airframe. Not as much damage but I had zero experience with epoxy or carbon fibre. Anyway, had a good crack at reading similar threads documenting repairs as above. Outcome, not very pretty but flies plenty good for novice me. Lots of good advice above. Give it a go.

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1 hour ago, mutogen said:

So, I did similar things not long after getting my first carbon airframe. Not as much damage but I had zero experience with epoxy or carbon fibre. Anyway, had a good crack at reading similar threads documenting repairs as above. Outcome, not very pretty but flies plenty good for novice me. Lots of good advice above. Give it a go.

Cheers Mutogen, ah yeah bugger that isn't it. Good to hear you got it in the air again. Yeah I managed to have a chat with Thomas from Armsoar about how to tackle it, so just got to make sure I've got all the appropriate materials and glues etc before I crack into it. 

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  • 4 weeks later...

Hey team, happy to say I managed to get my bamf back together and re maiden it this evening. Flew great all things considered, needs more tuning though. 1325745006_20211009_1548192.thumb.jpg.72500560d37d20a77f04d6903da050db.jpg

I'm yet to look at open tx programs for dlgs though as I was itching to het it back in the air. I think Neil said the one he uses is Frickman? Not sure.

Anyway thanks to everyone for the guidance! Thomas gave me some really good pointers too and put up with my badgering him. 

20211009_154826.thumb.jpg.3c453eba96374ddf08d0a6303acddec3.jpg

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If anyone is interested, here is what I ended up doing for the tricky part where the chunk around the bolt hole had been torn out. 

1802405243_20210925_1641472.thumb.jpg.93266b880c536f8ebebc5b21284f6588.jpg

 

I started by hollowing out the foam around the breakage area a bit.  

325792131_20210925_1724052.thumb.jpg.32d63c2918090e9af679d091559db97e.jpg

Next I glued the pieces back together with super thin ca, then milled a slot on the top skin down to the top of the bottom skin with a dremel. 

874764881_20210925_1738072.thumb.jpg.36dab118e76f474ebd6a5b22f60b223d.jpg

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Then I epoxied in 3x1.3mm carbon rod sections in stack in the slot I milled. 

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86668589_20210927_1820302.thumb.jpg.038d51095bcfac341368bdbbf67fcd71.jpg

 

Finally, dremeled out some hole in the top skin as you can see above ( had to make them a bit bigher than pictured above) to inject in some epoxy with chopped carbon fibres. Then once dry sanded a bit the patched over the top skin with 3 lahers of carboline 39/2 . That's more or less it. 

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so, my experience of fixing planes, is when you have bust one beyond repair, keep all the bits. Rather than laminating new carbon fabric over a damaged area, I have been salvaging patches of pre-cured skin material from a wing or tail, sanding the foam away, cutting a neat patch from it and then just bonding it on. Gives a much neater repair with a glossy outer surface, if you are lucky you can match the fibre directions and angles so it is barely visible, also much quicker.

 

tom

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Neil Harrison

I think Neil said the one he uses is Frickman? Not sure.

Yes, J Frickman in my opinion is the best F3K template for Open TX.

Lots of shortcuts like using the throttle trim to adjust camber settings which are flight phase independent.

It has all the competition flight tasks with built in timers allowing you to practice competition flying and keep track of your scores.

Information and download available here...

https://github.com/jfrickmann/SoarOTX

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