By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

How to reattach rear fuselage

All Topics | Latest Posts

Search for:  in Thread Title in  
Graeme Poke16/09/2016 10:27:57
avatar
175 forum posts
20 photos

Bad flying resulted in a bad landing which resulted in the fuselage breaking clean away just in front of the fin. Balsawood fuse, arf any suggestions please?

Thanks Graeme

gangster16/09/2016 10:52:22
avatar
929 forum posts
16 photos

Hi Graeme. Although it's hard to say without seeing it. If it a matter of the tail having broken off it might be as simple as just sticking it back together with epoxy especially if the balsa is quite thick ie 3mm or more with a good surface area of jagged edge. You might feel happier bridging the joint with thin balsa cut in such a way to spread the load. Ie cut on a slant. Careful not too add too much weight at the back end and inspect carefully for othe cracks. Take heart most crashes are repairable

Geoff Sleath16/09/2016 10:52:38
avatar
3271 forum posts
251 photos

A photograph would help, as would information on the model in question - ie size etc.

In general balsa models can be repaired though it's often not worth the time and effort. You need to remove the covering first then either replace or splint the broken parts. Is it a sheet or open structure?

Geoff

Cuban816/09/2016 10:54:14
2572 forum posts
12 photos

If you've got all the bits  the structure (covering removed) can be put back together 'jigsaw fashion', with  thin cyano wicked into the joints and possibly a touch of epoxy here and there.

A club mate who seems to spend alot of his time putting wood ARTFs back together after crashes, has worked miracles using this method on what to me is just a pile of matchwood - so it can be done.

Edited By Cuban8 on 16/09/2016 10:56:40

kc16/09/2016 11:14:52
5926 forum posts
168 photos

The important thing is to get the tail plane aligned correctly and secondly to ensure it doesn't fail in flight. Appearnce comes last!

If pushing the severed parts back to together and applying thin cyano doesnt work well then consider making a new rear fuselage to replace all the shattered parts and re-use the old tailpale & fin.

A compromise that works well is to glue the shattered bits back and get the tail aligned. Then if it doesnt seem neat enough consider inserting a new piece of balsa to replace the tatty part. Do one side at a time to keep alignment. Cut the replacement balsa to size and tape it over the bad part and cut around the new part into the old balsa. Result should be a hole that exactly suits the new balsa. Then glue it in.

Biggles' Elder Brother - Moderator16/09/2016 13:02:32
avatar
Moderator
15748 forum posts
1460 photos

If it is snapped into two clean parts - ie not shattered into a 1000 bits - then I'd strongly advise doing absolutely nothing to prepare the joint. Simply remove the covering and push the joint back together - using the jagged edges of the break as actual relocators if you see what I mean. Once its together, then wick thin CA into the joints.

This produces a very strong repair that is accurately aligned. Its strong because the farctured joints offer large gluing areas. Its aligned because it will only go together completely if the alignment is correct - the rough fracture surfaces effectively acting as a locating key.

Of course - this doesn't work if what you have is a "bag of bits" - but it will still work even if there are a few loose bits - as long as the there are plenty of "mating surfaces" between the two main parts.

BEB

Graeme Poke17/09/2016 04:42:55
avatar
175 forum posts
20 photos

Well that was quick. Thanks everyone for all the suggestions.This forum is great.

I have had this plane for 12 years and except for the occasional scratch and scrape it has never been damaged till now. It is my all time favourite and i want to hang onto it. Its an Ace R/C Staudacher 60, I don't believe they are made anymore, and a wonderful flyer. Until 2 years ago i had a Saito 90 in it but upgraded to a Saito 115. Really good fun!

It has snapped into 2 clean parts, jagged balsa edges and a good 90% fits perfectly. I intended to do as suggested by BEB and Cuban8. But then i worried that it would not be strong enough, considering the silly aerobatics i sometimes get up to. So i thought i would place a balsa doubler across the joins as suggested by gangster.

However i cant figure out how to get the doubler nice and tight against the fuse. I can glue one end of the doubler ok into, say the rear section then slip it into the front fuse.My lovely wife Kathy suggested i drill a 10mm hole through the fuse and thread cotton/string through the doubler and pull tight. This could work but maybe the doubler is not needed ......but i think there should be something.Kc suggestion is a good idea too. Glue it all up,then cut bits out and replace with new.

I think i will take the plunge, cyno it and see what happens.

Again thanks all for your input. Graeme

Piers Bowlan17/09/2016 05:18:41
avatar
1804 forum posts
44 photos

Once you have the fuz glued back together and it is all nice and smooth, a bit of filler might help here, personally I would use some glass cloth and epoxy to reinforce the joint. That way the joint is reinforced all around the circumference of the fuselage and will be much stronger (and neater) than a couple of doublers fixed either side. Cut some strips of glass cloth, wrap round the fuz and smooth some epoxy into it.

Just my 2p worth.

Rich too17/09/2016 06:26:45
avatar
2902 forum posts
1046 photos

That's what I was thinking. Or join it using cyno and then reinforce using carbon fibre strips/rods spliced in....

Edited By Rich2 on 17/09/2016 06:27:14

Piers Bowlan17/09/2016 06:44:35
avatar
1804 forum posts
44 photos

For a balsa model if you want to use carbon I would personally use carbon cloth/epoxy but carbon strips/rods/cyno when reinforcing a broken EPO fuz.

Denis Watkins17/09/2016 07:58:30
3740 forum posts
179 photos

In fairness to your flying Graeme, we often think one poor landing caused a catastrophic snap, but other than a high speed collision,

with fuselage tail, it is the weakest, thinnest loadbearing part of the model, I think it starts with a small crack, and over time, the next knock and its off.

We then hold our hands up and cannot beleive that the recent action could cause so much damage, and perhaps it didn't, perhaps regular use caused the damage to progress little by little

 

Edited By Denis Watkins on 17/09/2016 08:00:22

Biggles' Elder Brother - Moderator17/09/2016 09:03:40
avatar
Moderator
15748 forum posts
1460 photos
I know that it is very tempting to add all sorts of reinforcement. But before you do consider this, a close CA joint of the type I describe above, interlocking jagged faces, is stronger than the original wood! If the joint is well made, then if this thing fails again, it won't be at the joint, it will be in the wood. Its your call clearly, but in my view all a load of cloth, carbon and resin is going to do is add weight to the back end!
BEB

Edited By Biggles' Elder Brother - Moderator on 17/09/2016 09:04:37

Dave Bran17/09/2016 09:12:08
avatar
1898 forum posts
5 photos

At 12 years old be very careful of loss of strength due to oil ingress!

ken anderson.17/09/2016 10:21:38
avatar
8415 forum posts
772 photos

over the years some of the wrecks I've seen come back to life.....I would agree with young BEB...and say the repair will be the strongest part of your model,,,,after its had a re-maiden give it a fair old going over....to check the repair..

ken Anderson...ne..1 ..........young BEB/repair dept.

Biggles' Elder Brother - Moderator17/09/2016 12:21:13
avatar
Moderator
15748 forum posts
1460 photos

LOL! Good to know I've reached that venerable age in life!

Also what an honour - to feature in a Ken Anderson sign off line! Wow! An ambition realised!! smile

BEB

Edited By Biggles' Elder Brother - Moderator on 17/09/2016 12:22:34

IanN17/09/2016 12:33:51
avatar
1675 forum posts
119 photos
Posted by Biggles' Elder Brother - Moderator on 17/09/2016 09:03:40:
I know that it is very tempting to add all sorts of reinforcement. ............................................... Its your call clearly, but in my view all a load of cloth, carbon and resin is going to do is add weight to the back end!
BEB

 

+1 for that. Don't build in unnecessary strong points. All that will happen is that the next breakage will be right next to that point

I had a tail come adrift from the rear end of a sports model ( a Super Air, I think). Rather than be content with just gluing it back into it's seat, I added a couple of small external balsa triangular fillets and - for good measure - put a dowel each side of the fin down through the tailplane into the fus.

Result? Next time I had an "arrival" there was no way that tailplane was going to simply "pop off" again, so what happened? The whole fus snapped just in front of the tail assembly. Doh!

There used to be a saying. Every time you have a crash, look at everything that DIDN'T break and next time make it lighter

Edited By IanN on 17/09/2016 12:34:30

Martin Harris17/09/2016 13:07:11
avatar
8671 forum posts
214 photos

It's not just over strengthening you need to consider but also avoiding building in stress raisers. If you need to replace wood you need to spread loads correctly e.g. scarfing joints (diagonal joins) instead of just butt joining spars, longerons or sheeting. If you add a reinforcement, it helps to taper the edge of the over (or preferably) under laid part to avoid a sharp edge (think of snapping a piece of wood over the edge of your bench against doing the same on the sofa...)

ken anderson.17/09/2016 13:10:01
avatar
8415 forum posts
772 photos
Posted by Biggles' Elder Brother - Moderator on 17/09/2016 12:21:13:

LOL! Good to know I've reached that venerable age in life!

Also what an honour - to feature in a Ken Anderson sign off line! Wow! An ambition realised!! smile

BEB

...............................................................................................................................................

well done BEB...after a long period of consideration etc...it was decided to award you your own mention for service's rendered etc...the problem was finding a nominee to vouch for you...so at a bit of a risk...we took a chance... teeth 2 no doubt young Asher's nose will be out of joint now...because you've jumped the queue.... so be it etc..

ken Anderson....ne...1...... Awards dept 2016.

Graeme Poke18/09/2016 01:24:02
avatar
175 forum posts
20 photos

Thanks Dennis for attempting to absolve me of stupidity. However it was my own silly fault.

One end of our 70metre strip (its seems very short at times especially when I'm trying to land my Spitfire) drops away to a gully and it gets very turbulent there especially when the wind is from that direction.

I landed into the wind, (as you do) towards the gully a bit quickish, and with the end of the strip and the gully quickly approaching I stupidly pulled a bit of up elevator. Then things happened very quickly, well so it seemed to me ('m getting on a bit and my reactions are not what they used to be) It jumped back into the air and the breeze coming up the gully got under the wing. The Staudacher went up at about a 40degree angle, came to a stop about a metre in the air and dropped onto it's tail. What a crock!

Thank for the warning Dave. I checked and there is no oil ingress.

Another quick question. A mate reckons I should use aliphatec resin or Deluxe Super'phatic. My problem with those is holding it all together while it drys. I think cyno would be easier.

Thanks everyone for your help. I'll jam it back together, glue it up and hope for the best.

Cheers Graeme

Martin Harris18/09/2016 02:04:43
avatar
8671 forum posts
214 photos

Just make sure you use the thinnest CA glue - it travels along the cracks by capillary action...take time to align the parts as accurately as possible before applying the glue - you won't need to coat the length of the crack as it will work its way along a closely fitting join.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E! 

Latest Forum Posts
Support Our Partners
Wings & Wheels 2019
CML
electricwingman 2017
Slec
Pepe Aircraft
Cambridge Gliding Club
Gliders Distribution
Addlestone Models
Advertise With Us
Sarik
Latest "For Sale" Ads
Does your club have a safety officer?
Q: Does your club have a safety officer, or is the emphasis on individual members to each be their own safety officer?

 Yes we have a SO
 No, it's down to everyone

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us