Topic: Galaxy P51

Alan Wild a F3a flying dentist from Essex covered several versions of the same model in PVA and brown paper .It worked well until he tried to sheet/cover a 2m F3A model foam wing in brown paper without balsa sheeting .The wings lasted until the first flick roll ! .He did get a viable model in the end using carbon fibre spars under the brown paper. He named the model Xollod-oh  after what he said after each wing fold. He did get a goodish  finish on sheeted parts but it wasn't glow fuel proof.

Alan

CPLR used to use brown paper on all his competition F3A models but he did insert carbon tows in the wings. I believe he even used it on his TOC models. I don't know if he still uses it as this was 10 years ago when I had a chat about model setups with him.

Edit: Forgot to say, all wings were foam cores only with no balsa sheeting, just carbon tows.

This is another topic, save to say that I havesuccessfully used BP on bare foam  and veneered wings Paint has been Spectrum matt and the finish has not been affected by fuel. In deference to the finish, I keep them out of the rain, but otherwise I have found it to be a very serviceable method of finishing.

stu k

I guess it could be given a couple of thin coats of Ronseal after PVA and BP to harden up the surface a bit 

Ailerons roughed out and hinged just got to sort out what type of servo to Aileron  fudgery to do.  One of these days I will clear down the 3 benches I have and stop working off a 14" square bit of melomine on a workmate 



BTW the 1/2 circles on the leading edge of the surfaces are light ply, a little harder than balsa and gives something to sand down to the finish profile.

NFGood,
Nice explanation on how one use the tougher plywood trims to sand the balsa to shape the TE of wing to aileron/flap , respectively, to get that perfect shape. 
Albert

I just been looking at the general condition of the wing which is poor lots of small dings so it looks like my ex wife's @rse full of cellulite    It may just be today but I feel like I'm running out of puff so rather than mess about for ages getting hidden aileron links which will be difficult as the tip is quite thin in comparison to the rest of the wing I will probably just go for letting a servo in on it's side so the arm can potrude linking upto a horn on the aileron.

If I did still go the hidden link route can anyone see an issue with the picture below?  I would put a brass bearing tube over the piano wire with stops soldered on either side so it could not slide in and out that way when the tube is glued in place the pins cannot come out of the servo arm and would not need fiddly bolting/screwing.  The bearing slide bit in the aileron will be 1/16" ply soaked in thin Cyano I think that would make it wear resistant and when all glued up in the aileron I doubt the slot would be able to open up.



I would like to do the link hidden not really for this airframe but for the experience for something better later but it would make it easier to store and transport having less on the surface to catch on things.

Cant see a problem with that set up. I'll post pics later of the set I've just done for a 50cc Spitfire. If you put less bend at the aileron end then you shouldn't have to atv the servo travel down. Also, if you angle the whole set up, leaving the 'inside the aileron' bit nearly in the rib line, you'll need a small hole at the l/e of the aileron when you slide the aileron on.

Will work great as is though 

Ian.

................, you'll need a small hole at the l/e of the aileron when you slide the aileron on.

now that is cunning.... 

Thanks Ian for that  I had wondered about angling the drive so the bit in the aileron is in line with the ribs but that would move the servo rearward and could possibly not be deepe enough for it.  I put 45 degrees on the rod as a trial and seems ok but TBH I have no idea what sort of deflection I should be loking at.  I know it's not much unlike the Pup which has a bootful 

I'd imagine 30 degrees tops each way. Another trick you can use is to raise or lower the servo end of the crank, this gives differential which on some models is good. Power up the set up to see that you get it the right way round though. On my set up, the crank is similar to yours, but angled over, and theres a horn where you have the servo, with a 3mm rod to a remote servo. The crank runs in carbon tubes, for no reason other than it was a perfect fit. These tubes are slid onto the crank wire and a washer soldered to the wire at each end of the tube. Once installed the crank cannot then move forwards or backwards and gives a very positive slop free set up.

Ian.

Heres a couple or three pics of the aileron linkage on the 1/5 Spitfire I'm doing at the mo. The design is basically the same, just the actuation different. The carbon tube is in two bits to allow them to be moved out of the way while the washers are soldered on, to save them getting heat damaged. When installed, the tubes are slid apart to provide a good mount for the crank with no forward / backward movement. The box for the crank in the aileron is glass sheet. The two sides are installed with the crank in place, then they are boxed inbetween and also drilled and pinned to lock the two together, followed by end ribs to support the aileron skins when they go on. The ailerons were originally film covered but I've sanded a 1/16" off each side to allow for the new sheet.

Ian.

Thanks for those pictures.  I think it's possible to put the rod at virtually any angle, I have mine so when the rod is in the neutral position it is at 90 degrees to the hinge line the bit going off to the servo is at 30 degrees same obviously as the bend in the wire.  The box I have made fom 2 pieces of that copper coated glass board, 1 piece was very thin about 1mm so 2 together are solid and wont bend + give good abrasion............ well the copper may not 

I'm just about to cut the servo box into the wing which will be in line with the main spar servo sitting on the cosh in it. then I can trial it all but I have to solder on the fork end in situ either that or cut a slot for it all to go in so will solder it when it's in place.  I wont upset teh solder that I used to make the fork up as thats silver solder and the 2.5mm rod is just about small enough to solder with an iron and stiff enough not to flex when complete 

I noticed also my work is getting rather sloppy and untidy    Must stop rushing and be more careful how I handle everything it's all getting rounded dented and dirty.

I would have liked to done it your way Ian but that would mean bigger holes and how I'm doing it there is only just enough depth in the wing.  I really don't think the geometry is a big issue and I think should I require more aileron movement I could remove the wire and put more angle in it as I have allowed for extra movement in the glass box.

<a href="http://www.youtube.com/watch?v=lBdxGvhvIpc" target="_blank">http://www.youtube.com/watch?v=lBdxGvhvIpc</a>

More movement needed?  I can easily bend the rod at the moment.

This is taking forever I'm miles from done on just the wing alone still have the fuselage to address yet :(

I cut the slot for the aileron servo wire 1st with razor saw against a straight edge then made up a quick piece of wire which was heated dropped in the slot and excevated the surpless foam.  I will fill the top with a piece of 1/4" balsa and glue that in with PVA if I use gorilla it may expand and fill the slot.

Do you happen to know where the COG point is, got a build manual but no specs

C of G, I have no idea    I was going to go with 25% of the wing chord drawing a line on the leading edge straight along and through the protruding inner part if you see what I mean failing that ask the question as you have on here somewhere 

The c of g of mine was about where you are suggesting and it was fine .The engine was a saito 180 and no nose weight so your z 38 will probably make yours nose heavy. I regret selling mine it was rough with fixed UC but it flew well and sat in the air nicely I might buy a new kit at some point as they are not that expensive I keep a lookout for second hand retracts 

Alan

I been doing a little on the aileron this morning and I'm very disappointed with my poor workmanship.  I started this project with a poor attitude and the only interest being to fly the finished thing.  I have rushed most of it making stupid mistakes along the way and am paying the price now, regardless of how much effort I put in I wont be able to make things line up 100%, neither flaps nor ailerons are a perfect profile, hinge holes are not drilled perfectly etc so I'm fighting with everything being slightly wrong and trying to even things up to look right.
I'm not having to unsolder the aileron link so I can take it out and file the hole in the trailing edge of the wing 1/32" upwards, only a little bit but it makes a huge difference to both action and look.  Having the ply fairings which have close tolerances to the aileron it shows every little misalignment and profile being wrong.

Big lesson learned.......... don't start anything unless your heart and mind are totally focused on the job.

I thought I had my attitude in line so attempted to cover a flap with PVA and brown paper............... what a fecking mess that was so ripped it all off wiped off the pva best I could and left it in disgust.

I thought I had my attitude in line so attempted to cover a flap with PVA and brown paper............... what a fecking mess that was so ripped it all off wiped off the pva best I could and left it in disgust.

Stick with it Shaun     Practice makes perfect.

Alan

What was the problem, glue not thin enough, leaving too much under the paper? Too wet, paper not sticking and falling apart?

Ian.

PVA water 50/50 painted on with a brush, paper put on poor adhesion and and wrinkles so bad when I ran a credit card over to remove excess PVA it would not flatten out rather buckled over and caused a ridge.  I know it shrinks but could see not way it could shrink enough to take ridges out + the sticking was not good on the edges regardless of how much or little PVA was on it.  Made no difference wetting the paper 1st either so rather than adding to the work trying to rub down (I would have burned the fooking thing instead) I removed it and gave up.  This was on a nice and easy flap the only caveat being the rounded leading edge which should not be a problem should it and I did it indoors so it was quite warm around 16 degrees.
I keep thinking give it another go, try again more PVA less squeegeeing etc but I'm loosing interest in brown paper (and my abilities) thinking perhaps Diatex and cellulose clear coat then a couple of coats of polyurethane varnish but that would mean buying more clear coat I don't think I got much left from the tin I bought 15 years ago.

I have just acquired some brown paper and bits to give it a go on the Chipmunk.

Seeing as Shaun is having issues, so by default so will I,  any chance someone on here could describe how it should be done 

Sorry Shaun, don't want to hijack, but maybe a word from the wise is all thats needed 

Charlie C

Shaun and Charlie.

Granny eggs time.
Have you tried on a scrap piece before committing to a model?

Kev

Gona get my coat and leave now.

this any help??

http://www.rcgroups.com/forums/showthread.php?t=190499

Shaun and Charlie.

Granny eggs time.
Have you tried on a scrap piece before committing to a model?

Kev

Gona get my coat and leave now.

Hi Kev,

I have never used this covering method before and was going to play on some scrap first. (plenty of that in my workshop  ), however a few words would go a long way and possibly lead to less practice 

Charlie C

Although I've not used this technique I believe it's a bit like wallpapering (no, I don't mean a dull and tedious distraction from modelling).

Get it on, get it wet and flat and leave it to dry out - the paper swells up when it's wet but more important, it shrinks when it dries out properly.

The test piece (or knackered old wing is) is definitely the way to go (that's two grannies and four eggs ).

If your problems persist, I will talk to my mate and LMS proprietor who flogs a range of foam kits that are all brown paper covered for hints and tips and pass them on.  Come to think of it, one of his little Spitties and a brushless setup would be an ideal thing to have  lurking in the boot of my car.  Is it Christmas?

Alan

Shaun & Charlie.

Should also add that I have never been down the route of BP either, though I did once consider it.
I am also considering it again when I cover my as ye unpurchased wings for my Chorus Gull.

Apologies if my remark seemed a little flipant.

Kev

Shaun & Charlie.

Should also add that I have never been down the route of BP either, though I did once consider it.
I am also considering it again when I cover my as ye unpurchased wings for my Chorus Gull.

Apologies if my remark seemed a little flipant.

Kev

Yer alright mate.

I didn't take it as flippant at all 

Charlie C

Have you tried on a scrap?

Kev

Most likely,  I used the Flap I intend to use on the finished airframe

this any help??

http://www.rcgroups.com/forums/showthread.php?t=190499

Thanks for that, I have read that one and also http://www.rcmf.co.uk/4um/index.php/topic,38088.0.html which says wet the paper 1st unlike the rcgroups post 

I ve done 3 MR discos using that method with no probs cut edges and overlap when dry another coat of pva neat then sand works for me.
 

I've used it quite extensively on EPS foam models and found it made little difference wet first or not - I ended up not wetting it.

I used about 30 - 40% PVA white glue mixed with warm water and allowed to cool. Shake before use.

I paint one surface then lay the paper over it - shiny side out. I lightly brush it and smooth any wrinkles out with my fingers. Don't over work it - it stretches unevenly and you end up with a mess. Aim to work with it as little as possible. When you have a smooth surface do the other side. Leave to dry hanging up by one end - at least 24 hours in a warm dry-ish place.

Sand very lightly - I start with 400 grit wet and dry used dry and go finer.

HTH

Richard

I've only used brown paper a couple of times, its cheap enough but I find its a pain in the ar5e to do, but the results were pleasing enough. I always wet the paper first, also sealed and gave the airframe a coat of thinned pva too. Then after making the panel to size, wet the area on the fuz with a quick coat of thinned pva. Lay the panel on and squeegee out. Some people use an iron to dry the glue and iron the paper on, like solarflm, but I never tried that and some of the results I've seen look a bit cack if I'm honest.

Ian.

I wouldn't do it that way any more though, I find glasscloth and resin the best way for me, it aint that dear considering the amount of resin you actually use and the time is saves.

Ian.

 have  followed the ideas printed by Chris Golds. Always though it a good system.

Cut BP panels to size, apply paste to slightly dull side of paper and leave 5 mins to expand.
Apply paste to airframe, adding food dye helps to see coverage.
Smooth paper onto airframe.
Cover other side as above and  allow for generous overlaps.
Apply paste all over and allow to dry thoroughly
Sand, Reapply paste, final sand and paint.

The BP really shrinks as it dries so control surfaces are best pinned to something solid to avoid warping. Use cling film on table to stop it becoming a permanent feature.

I appreciate that some have said to apply the paper dry - I have always thought that pasting the paper, letting it give before applying to the wood, is essential to get the shrinkage as it dries.

stu k

I find glasscloth and resin the best way for me,
Ian.

I already done 1 long reply to this but Firefox dumped out 

Anyway, where do your procure your materials?  Do you use Phils superfandango stuff?  Is it something I can buy online (don't like leaving the house  ) or can I nip out to a local glass laminators we have plenty around in Norfolk.  I have read there are several types of resin some leaving a sticky like surface obviously that's no good and do I have to be careful about it being a foam wing?
I have never glassed a airframe my only experience is from years ago using 2" glass tape on the joins of ply built racing dingys when I was  a lad I was a keen sailor.  Will the cold weather be an issue I have no heating in my toy room.

I use Fighteraces resin now, a brilliant product that goes a long way. Cloth I tend to use is 24gram, Deluxe Materials (?) stuff at the moment.

Ian.