Topic: Repairable?

Had a mid air today. Fuse survived. I like this plane a lot, and wondered if this wing was repairable?

Yeah. Glue back together and glass the break.

'tis but a flesh wound

Yeah. Glue back together and glass the break.

Is that all? You mean glass fibre bandage? How far each side?

'tis but a flesh wound

      Tis But a Scratch

                Bob

A scratch. I wish.

Phase 6 nosed into my wing at high speed. Wing had no chance. Smashed it to bits and plane spiral dived into the deck from 200ft.

Surprisingly no other damage, apart from the impact with the P6. Ground did no further damage.

P6 was undamaged and kept of flying.

Close up of wing after covering removed. The p6 must of been carrying razor blades on board.

Bit of epoxy and some plywood slivers and job is a goodun 

Bit of epoxy and some plywood slivers and job is a goodun 

I'll need a new bottle of epoxy..

Yes damage looks repairable. Should be back inair by next weekend

Hi Pilot Jimbo
The secret of doing a repair like this is NOT TO RUSH Treat it like an aeromodelling jigsaw puzzle and gradually build up larger and larger bits made up from the broken smaller bits. 
Treat it as therapy and look forward to the comments you'll get when you finally fly it when your friends and fellow fliers say "Goodness me! (or similar)" I honestly thought that one was a goner - you've done the impossible" etc, etc
Bit at a time (literally) not too much local strengthening - adds too much weight' lots of well rubbed down lightweight filler and recover with Oracover - preferably a dark colour - hides a multitude of sins

Good luck
Pete

She will have to be matchwood before I chuck away...

Going to try to reinforce with small balsa/ply spars. Will try to avoid epoxy glass bandage as that will spoil the airfoil.

Repair is a must. I had an Akrostar for several years, never really knew what I had!
Way better than many very recent so-called aerobats... ;-)

Good luck


Ju

I agree. It's my favourite plane. I think flying her in 40 plus was pushing the envelope. But she flew ok, loaded with lead sheet. What happened to yours?

Hu

Glued her back together. Epoxy/balsa/carbon spas. Also carbon also where the p6 nose entered the wing.

Looks good Jim

Was that the ballast you were using yesterday?

I had insufficient lead in the Carbon Bird yesterday and planted it as a result.

Fortunately, the cheap epoxy I had used to stick the V-tail on came away cleanly so I have no real damage to repair, just a bit of Re-kitting.
 

Tim

Haha. I had the same on the other side..

Sorry to hear that you stuffed it. Yesterday was a big ballast day. And a model wrecker day.

I had about a lb. Not enough.

You fixing her or is she a write off?

SLOPE eh.

Smashed lost or pulverised eventually.

Turned out ok. Prior to sanding/covering. Shell be back on the slope on Sat.

Hehe. So much for mid airs and spiral dives. We have the technology.

Re maidened the acrostar today. I can report it still flys fab!

Re maidened the pyscho also today. Also still flys fab.

We have the technology.

Pics to follow.

Broke my Pike Extreme 2 weeks ago, flew it again yesterday( see before and after pic's ) No new parts required just a bit of graft!!

A week last Monday I did this, yesterday she flying.  The weather was the delay 

Nice one Mark.

Hope to see pics of the pike extreme too!

Well I stuffed the acrostar again. Was a straight wings level landing. Again I couldn't slow her down this time she hit a bracken tree spun and the fuz broke. No other damage. Since she's my fav plane this time she's due some special treatment. I'm going to fix her up with a nice big drainpipe through her centre. Hopefully this will improve her midriff strength something which is sorely lacking on such a fast plane. I'm seriously considering chopping the wings to add flaps so I can slow down the landing approaches. Here's the pics. You can See the drain
Pipe is cut and clamped ready to go into fuz. Any tips on how to attach? Laminating epoxy? I have some carbon sheet I could also put around the pipe, but it's so bloody strong so I dont thing it would be needed.

Here's the dry run install of the drainpipe.

How can I ensure i get good adhesion on the inner surfaces when I glue?

Here's the dry run install of the drainpipe.

How can I ensure i get good adhesion on the inner surfaces when I glue?

What's the drainpipe made of?

I guess I'd be slathering it with laminating epoxy with colloidal silica (cabosil) to thicken it, or since there's so much surface area and gap maybe gorilla glue that forms a lightish foam would be better and cheaper.

However my track record on repairs holding together isn't brilliant when impact tested :embarrassed:

Had a few more ideas on how to strengthen the inherent weak point on this plane. Added a second drainpipe around the front section with a former. Will cut out of ply. Here's the view down the fuz so far. To think that the standard kit has no reinforcement in this area. Crazy.
It will take a) a bag of a million bits, b) getting hold of a replacement, to get me to bin this plane.
Not sure what the drain pipe is made of. It's wickes standard house stuff. Very tuff.
Gorilla glue might work, but there isn't going to be much clamping as I can't get down the fuz.
I think I'll just mix a carbon and laminating epoxy mix and use that. Silica will weaken the mix. I want this repair to be for keeps.

Not sure what the drain pipe is made of. It's wickes standard house stuff. Very tuff.
Gorilla glue might work, but there isn't going to be much clamping as I can't get down the fuz.
I think I'll just mix a carbon and laminating epoxy mix and use that. Silica will weaken the mix. I want this repair to be for keeps.

I was wondering if the drainpipe was one of those plastics that epoxy doesn't really stick to. Definitely key it first, use rough sandpaper (60/80 grit?) all over it. Gorilla Glue shouldn't need clamping when it's squeezed into the gap - or is the drainpipe+glue not completely filling the fuse up?

As for silica weakening the mix, I though silica made it harder and tougher, its microballoons that make it weaker.

Ah. I didn't think that was the case with drainpipe - I expected it to fix... I was intending to key it anyway though. Is this not gonna stick?
Yes I was thinking of micro balloons. Maybe that is the case.

Ah. I didn't think that was the case with drainpipe - I expected it to fix... I was intending to key it anyway though. Is this not gonna stick?
Yes I was thinking of micro balloons. Maybe that is the case.

I'm not sure about the drainpipe. I know I stuck a plastic inner nose to a fibreglass fuse and it popped out again very neatly, leaving a perfect mould of the plastic... but I hadn't really keyed it anywhere near enough, I now realise.

With additives, I'm no expert, but:

microballoons: thicken the resin, make it lighter and less dense, more easily sandable and paintable

Cabosil/colloidal silica: makes the resin set very hard, also thickens the mix some for gap filling

Milled fibres (fibreglass strands milled to 1/32" long or less) - very tough when set, goes a bit like well cooked rhubarb when mixed in, good for gap filling but not pretty or easily sanded.

wood flour - a cheaper additive that works like microballoons - good for filleting and filling

Hope that helps!

I did the first glue of the drainpipe. I think this is gonna take all night to set, damn wet and cold. Should have some spare time as no flying in mids on easterly :( 

Here's the pic.
Oh she looks like she has seen better days.. She has had eight of the 9 lives.

I think you need help from Tony Fu ...

I did the first glue of the drainpipe. I think this is gonna take all night to set, damn wet and cold. Should have some spare time as no flying in mids on easterly :( 

Here's the pic.
Oh she looks like she has seen better days.. She has had eight of the 9 lives.

What glue did you go with in the end?

Can you put it anywhere warmer to help it set? I don't know if there's a point at which it just won't set correctly if it's too cold?

I did the first glue of the drainpipe. I think this is gonna take all night to set, damn wet and cold. Should have some spare time as no flying in mids on easterly :( 

Here's the pic.
Oh she looks like she has seen better days.. She has had eight of the 9 lives.

I let stuff dry inside in the warm, actually on the dining table which is next to a radiator, which is a real delight to the wife.....
Airing cupboard is another good 'un provided the epoxy still isn't still runny and the part isn't too big, although with combi boilers they're becoming a thing of the past.

You can make it look better Jim, depends how mush 'slap' you put on the old girl and how much time you want to take doing it. Seen some planes in awful states posted on RCGroups which look fantastic when finished, a real credit to those who can.

Yoyo, no expert but I think it just takes longer to go off properly, I suppose if it's really cold it might not go off at all? I had 1 job that sat in the cupboard for a week and was still slightly tacky. Once put in the dining room it set better after a day or so, but it could have been my mix ratio as it was the 1st plane I tried to repair

I've only just seen this thread, and if the drainpipe doesn't work..I'd take it out...

Get some CF open weaved cloth... Line up and splint the outside of the fuz, with lengths of wood and masking tape wrapped round.  Make sure it's absolutely dead straight. Lay in the cloth on the inside, tacking it with CA in spots (Take your time!)...Mix up the appropriate resin (epoxy or poly), and apply carefully to the cloth. Allow to set.. Fill the gaps on the outside, repaint. Install radio etc..fly.

Guy who used to be on here (not sure if he still is) worked for McClaren and told me that. I fixed a Sagitta fuz and it was incredibly strong afterwards.

I've already tried the carbon cloth epoxy method before. Not strong enough. The problem with this is the speed. It goes like stink otherwise it stalls and then it drops out of the sky hard. And with no flaps landing is always hairy and fast and damage occurs as the wings are also very heavy at 2.5m span and have some sort of floating setup.

So I've decided on the drainpipe to beef up the fuz. I usually fly with ballast (lead strapped to bottom) so weight isnt an issue. I need her stronger around the midriff as in standard form its inadequate for the abuse it gets. So I've piped her from   4 in behind to 3 in front of the wing. It already feels stronger.

The epoxy I used is some decent laminating mix to which I added 1/32 strips of fibreglass matt to make a nice thick goo. I'm sure it will go off in the am.

Can't epoxy in the house, tje stink and mess isnt popular with tje family so it's always in the cold workshop at bottom of garden. I checked it after tea and it was going off. Tje worst think about slow sticking is you don't know if you mixed it right till tje morning. I've had this stuff go off in 4hrs on stinking hot day in the summer. Otherwise it takes longer, and it's supposed to be fast setting! It is fast setting in California or an oven..

As an aside, I've since bought a gulp sv 60 so now there is slightly more chance the acrostar will be kept at home when the wind hits 30 plus ( was 40 plus when I bust her last time) and I'll have something to fly, and I can save the acro for 20-30.

Maybe a good project would be to make a new fuse at some point.

I had an SAS Ace with an all ply fuse which was quite amazingly strong.

Of course you could try to make one fron cloth/resin - e.g lost foam method.

I think I would make a slimmer fuse from ply . Could add balsa to get a more rounded shape (like on a middle phase). And glass that. Nice set of wings with good performance - be a shame to have to retire them.

I don't know if your drainpipe will stick tbh. I would have used carbon or glass cloth..... Be strong if it does though.

Where did you fly it in 40mph? Most models land into those headwinds if they are not in lift. Even my thorn will fly slower than 40mph and that is pretty heavy and not forgiving.

Do you use flaps or spoilerons? Try down flap if spoilerons don't work

That is what I will do once the fuz dies.

Last flight I even stuck the rudder linkage with cyano on another cyano repair, and was flying with no rudder. Was a great flight up at dassett in 25. Stall turns still great, cubans, reversals etc. But the landing bust the previous cyano only repair. :(

I will copy the acrostar fuz and make my own, keeping tail/rudder. But not until I lose it... Which is incidentally was the reason Dave G stopped flying his acro.

Spoilerons ineffective. Not tried drooping the ailerons.

If I redo the fuz I might as well add flaps..

Get some CF open weaved cloth... Line up and splint the outside of the fuz, with lengths of wood and masking tape wrapped round.  Make sure it's absolutely dead straight. Lay in the cloth on the inside, tacking it with CA in spots (Take your time!)...Mix up the appropriate resin (epoxy or poly), and apply carefully to the cloth. Allow to set.. Fill the gaps on the outside, repaint. Install radio etc..fly.

What sort of weight cloth, and one layer or several?

For my own repair (one of many I've got lined up :( ), I've got available 200gsm woven glass cloth, 240gsm carbon or 190gsm kevlar. Which would be best for a glass fuse?

At the moment I've laid up three layers of the 200gsm cloth round a bottle to make a spiral strip that I can then coil a bit tighter and fit inside the fuse to support the join. I tried one layer at first and it was way too thin, like paper. It even tore. Unfortunately on the three layer version the resin soaked into the greaseproof paper I wrapped it with and the paper is permanently attached now, until I soak it and rub it off. Oops.

If the carbon or kevlar would be better, it's not too late to change it.

Yoyo, I've found that you need to add full carbon sheet 200 in and out of the fuz. One side isnt strong enough. And the problem is on the inside you can never get enough compression to make the epoxy anchor ( which you can if you use the right diameter drainpipe). Fingers crossed it sticks for me.

Someone needs to invent a fuz clamp that expands outwards like a drainpipe does under compression. Maybe Tony Fu will read this and tell us what he does to anchor down the fuz?