1/10th scale Blackburn Beverley.

[Steve Mansell]

Sorry to hear the house fell through, but what a bonus for us that are addicted to following this build!
Cracking job!
Steve

[DAVE JOHNSON]

Malcolm--- enjoy looking at the daily updates on your build---hope you find time to carry on.
Today I visited BAe Brough on LMA business,and that is the old Blackburn factory as you probably know---I mentioned your build and they said if they could be of any help with info etc then to please contact them---I have all details on file if you need anything-----DAVE

[MalcolmDouglasPorter]

The hangar is back in business! The fibre glass stuff turned up today. 48 gsm glass cloth x 10 sq metres, gunge and catalyst, mixing cups, spatulas, gloves, disposable brushes and 50 m. 30mm carbon fibre tape. I will use this tape to augment the tail plane main spars, amongst other things. I have a roll of 2" 285 gsm carbon tape on the way that will be used on the main plane spars. This thing will not bend!

Thought I'd make a start on the wings stuff today. I still have rakes of jobs to do on the fuselage and will progress these when the old inspirations kicks back in. However, the pictures show today's work making the tail main spars. Next up will be the centre jointing pieces for these spars then perhaps the secondary spars before making the aerofoils and elevator parts. I will be looking for some advice on fitting the servos in the tailplane and fins and their positions in relation to the control surfaces. Perhaps some suggestions for the types of servos would be helpful?

[Alan Cantwell 1131]

Malcom, have you done glassing before?

[MalcolmDouglasPorter]

Yes Alan, but not on model aeroplanes.

[Alan Cantwell 1131]

Can i suggest you seek help on this, as its way to easy to over resin the glass, and add lots of weight, lots of tutorial on here, my mates jonsey, (dc3 build, on here, ) along wirh my mate Alan, are ace, look at Phil Clarks threads, lots of info on here

[Phil Clark]

Malcolm

Not wishing to piddle on your fire, but I'd strongly advise AGAINST using the West 105 resin for skinning, especially if the pack you have has the # 205 fast catalyst

West resin produces quite a lot of wax when it cures.....this is a REAL problem. Once the resin is cured, both the 1st coat that's used to apply the cloth & the 2nd that's used to fill the weave......you will notice a waxy residue on the surface. Not only does this make rubbing down more difficult as it clogs the paper, but if you don't remove the wax from the 1st coat prior to applying the 2nd, the 2nd coat is unlikely to get a good bond + if you don't remove every last trace of this on the 2nd coat prior to primer, you'll get all sorts of orange peel/fish eye problems with your primer as it reacts with the contamination of the wax on the surface.

Some resins produce this wax, others don't......West in my experience is one of the worst.

The 2nd issue is with the # 205 Fast catalyst......it gives a pretty short working pot life.....no more than 15-20 mins which isn't long when you're glassing large areas such as the Beverley. The slow catalyst is a lot better giving more working time, but it still doesn't get away from the wax problem.

3rd issue I have found with the West is it's consistency....it's very thick to work with, doesn't flow well and is difficult to apply to 48g cloth 'lightly' so as not to add excess weight. Warming the resin slightly improves this, but reduces working pot life as adding heat speeds up the cure. Adding an epoxy thinner can also work, but I've always found adding a thinner destroys the properties of the resin & it never dries quite as hard as it does if un-thinned. Soft, slightly rubbery resin is a pain to rub down smooth as it clogs & balls on the surface......rock hard resin is easy as it forms a nice fine dust & doesn't clog. Simple facts are, there are 'thinner' resins about that are far easier to work with that require no thinning.

I also note to have a stash of large graduated mixing pots there.......use these ONLY to mix the resin, do not leave the resin in them whilst working. To improve pot life, you need to decant the resin out into a large flat vessel with maximum surface area and minimum resin depth. If you leave it in a small vessel with limited area and more depth, the catalysed resin will start to produce it's own heat speeding the cure time and reducing pot life.........in a large shallow vessel, this problem is reduced.

You may find this 'How To' tutorial helpful if you've never glassed a model before......

http://www.fighteraces.co.uk/wp-content/uploads/2013/02/glassing_article.pdf

Hope some of this is of use...............

Phil

[Alan Cantwell 1131]

Hows about that then Malcom, top bloke is Phil,

[David Jones]

Malcolm, Fighteraces and Bucks Composites (formerly Fibretech) are definately the best resins for modellers use. With a little heat you can get their resins as thin as water and it goes a really long way. It takes overnight to cure, even longer in cold weather, but it sands a treat. Don't wory about trying to get a "glass" finish with your second coat, just a nice smooth surface will do. You will get your finish with primer, filler/stopper and a bit of elbow grease...well worth the effort. Hope this is of help, Jonesey.

[Alan Cantwell 1131]

Another top guy,

[MalcolmDouglasPorter]

This is what being a member of the LMA is all about! I am building extensive knowledge about the various aspects of LM building. I have watched several video tutorials on line, but none have told me about the wax residue problem, they are mostly about method. I am extremely grateful that you guys have taken the trouble to give me the benefit of your experience and knowledge. By the time I am ready to do the glassing, I will have learned a lot about the pros and cons. I have no fears regarding the practical side of this, but the technical stuff is beyond me, but this is now beginning to make sense.

I have now emailed the suppliers if this West 105 resin and asked them for some technical answers or if they will take it back for a refund, it was over £28.00. I did actually order the slow cure set but got this fast one, so that is their fault anyway.

I am still asking for advice on the positioning of the wing servos for elevators and rudders, and the types of servos I should buy!

Once again, thank you!

[MalcolmDouglasPorter]

Didn't do a lot of work today, just finished the tail plane spar apart from the outer ends where they will eventually accommodate the fins. This will be done in association with all the other relevant parts. I have cut the seating surfaces, but may need to adjust these when all the parts are made and ready for assembly. I think they need to be cut back a little? As you can see the seating looks OK at the mo. I have also started making the aerofoil patterns for the tail plane.

As this part progresses, I will need to learn about servos & control rods etc for the tail plane and fins? Some ideas on hinging will be useful.

[Alan Cantwell 1131]

The Bev has three mass balance tabs, conveniently at the top, bottom, and middle, this to me points to a frise set up, look at Jonesys B25 build on here, the way to go is a brass tube through the hinge point of the rodder, and three brass tubes down the 3 tabs, pass a piece of piano wire straight through, lining up all areas carefully, the top of the wire has a balsa piece, separate from the fin structure, but sanded as part of it, this, when pulled, leads to removal of the rudder, a nice bonas, This lot, by the way, is not my idea, its jonesys and Alans, I will find out what servos they used in the B25 rudder, and get back to you,

[Phil Clark]

Horns & linkages...............

To prevent control surface flex, it can be preferable (though not always scale) to position the control horns centrally along the LE of the surface. If the horn is positioned at the root end, unless the surface is built very rigidly, flex along it's length can occur.

Horns and linkages obviously must be set at 90 degrees to the hinge line & servos positioned accordingly. Try and keep all linkages as short & stiff as possible. My preferred linkage set-up is a twin 1/16" glass board of carbon horn on the control surface (set into hard balsa blocks or sandwiched between liteply ribs) with a 6mm gap between the horns to sandwich a heavy duty M3 ball link. The linkage itself is made up of a metal M3 clevis at the servo end, connected to the ball link with a length of threaded M3 steel rod. A lock nut is used against the clevis and the exposed M3 rod is sleeved in 3mm I/D carbon tube to further stiffen the rob (+ make it look nicer!!!!)

A set-up such as this should be more than adequate for the main surfaces on the Beverley.......I'm not familiar with the flaps but I suspect they are huge so something a little more substantial may be required.

[MalcolmDouglasPorter]

Thanks for the info chaps.

Alan, The idea you suggest is what I have planned for all of the control surfaces on the Bev. The difference is that I was considering using carbon tubes. The balsa tab on the end of the wire is a good idea though, perhaps I could work on that.

Phil, It seems that I should have a look at the sale stands at the shows, there is bound to be an array of control bits and pieces.

Today I have been doing some work on the tail plane. First job was to sort out the rearward rake on the spar, this required a delicate cut in the centre almost all the way through, leaving enough wood to bend the spar to the correct angle. Once the angle was established, using an adjustable bevel, I cut a wedge piece to glue in place. The glue job had worked out very well, I am amazed at the strength that this still has, although I will do something with some carbon fibre later on. I have mentioned cock ups on here before. Despite measuring and marking carefully, I have managed to make an aerofoil too short at the front end. This is the one on the right of the second picture. The annoying thing is that I made a nice job of the item, just too short by about half an inch. This is why I did not make its opposite part.

You know me and my dry runs, got to do it!

[MalcolmDouglasPorter]

Didn't get going too early today, the house move (not moving) thing is getting me down a bit, the market is slow to stagnant!

Remade yesterdays cock up (7/16" short) aerofoil and its partner and the next pair which starts the elevator section. Starting to get serious now.

I have been doing some research on the waxy deposits on resin problem, there is a load of info on the web. It has a name, "amine blush". This waxy substance is in fact water soluble and can be cleaned off with just water and a Scotchbrite pad and unbleached paper towels. You should not use solvents or rags to clean the surface as the solvents can dilute contaminants in the rags and deposit them on the resin surface, causing bigger problems. Sanding the amine blush will not remove it, but is likely to drive the stuff deeper into the surface and impossible to remove. You should Google "amine blush" to see for yourselves. I have also emailed people in the industry to get some info, and one technical manager said that this problem is probably related to curing resin in too low temperature, this causes moisture in the atmosphere to absorb into the uncured resin and cause the blush. Quote:- "it is very important to ensure that the Epoxy Resin is cured at 20°C for the full cure cycle of the resin, Epoxies by their nature are hygroscopic so if the temperature drops too low during the curing cycle, the cure will slow down or even stop and the resin will absorb moisture from the surrounding atmosphere", unquote. More research to do but I am beginning to get a grip of this.

[John Greenfield]

Malcolm

A change to G4 for the application of the glass cloth will solve all your problems. Do a search on this forum and lots of info will come up.

John

[Phil Clark]

Temperature does play a big part I agree, but to say 'water' can be used to remove the residue is utter rubbish in my experience. Fibertech (now Bucks Composites) used to sell a solution specifically for this purpose.....even that didn't work.

Phil

[MalcolmDouglasPorter]

Been pottering about with the tail plane this last couple of days, the progress is slow. Most of the time is taken up marking out. This is more complicated than I expected it to be, but I will get there. Probably a fair bit of fettling and adjustment to do as this needs to be about right!

I have been continuing my research into Amine Blush, the residue on resin. Another quote from an industry professional. Quote:- “The outer layer can suffer what is known as an Amine Blush whereby there is a moisture rich layer on the outer surface which won’t cure – this can normally be removed with methylated spirits and a clean, lint free cloth but the best remedy is to prevent it from occurring in the first place and the best way to achieve this is to work somewhere warm and dry”. Unquote.

[Alan Cantwell 1131]

All very well with your research, but are you going to take the advice of some of the worlds best, or try it with the stuff you have? We await with baited breath ! if you do it your way, please try it on a piece of balsa, first