Mossie

[Sean Tracey]

I normally soak sheet balsa to form it around curves , I notice some people talking about ammonia to bend . Can I buy this in any Chemist ,is there a brand name or brand product? What size ,? Do I dilute it down ?. Thanks I really need some help with this.

[Martin McIntosh]

Hi Sean,

I got it from a local general hardware store in a 500ml bottle. Use it neat. It is just a cleaning agent.

[Martin McIntosh]

Got the first doors from the acetate mould OK. A fair bit of work trimming these and fitting balsa edges and ribs to get them to fit but with a little extra still to cut away there is now oodles of room for a rounded or square wheel. Still undecided whether to use them or go back to the balsa ones which could be thinned down after glass skinning maybe. GF ones only 4gm heavier. I shall decide after I see what the second set turns out like.

[Martin McIntosh]

Got the tail mount level and ready to fit but must first make up the tail wheel assembly. Mistake here since when I cut a mock up from tinplate I realised that it cannot fit my chosen retract unit which came from the scrap box and required a new centre turning up on the lathe then drilling and threading a. Much time wasted here but a better one was sourced and turned up the next day for a change. I shall cut the real one from brass plate later.

[Martin McIntosh]

So on to the cockpit and nose. I positively hate painting and fitting `little men` in here because I am more of a Lowrie than a Leonardo but some people moan if I don`t do it. Once in and hidden by the canopy they do not look too bad to me. No point in trying to add more detail here since it could hardly be seen. At the last moment I realised that the batteries would not fit with the full instrument panel so this was vandalised.

The bomber nose was tricky to shape and fit so a little filler to make it blend in will be needed.

Lots of care cutting out the canopy recess is required since this is rather different to, say, a Spit. one. Mine has been glued on with foam safe C.A. to avoid any blooming. I would have preferred to have glassed the fus. first but this may have made the gluing process more difficult. Pics to follow.

[Martin McIntosh]

[Danny Fenton]

Looks really good Martin, how are you going to retain and stabilise the pack?

Cheers

Danny

[Martin McIntosh]

Never used packs of this weight Danny. They are on Velcro so cannot move fore or aft and the former prevents upward movement. Just did it as shown on the plan. Nowhere to attach straps. I think that the problem will be actually trying to remove them so will have to use the metal ruler trick.

[Allan Bennett]

I haven't perused the plan properly yet, but wouldn't a sliding battery box or tray be the best solution here?

[Allan Bennett]

With my SE5a just waiting for some more material to cover the wings' upper surfaces, I started on my Mossie a couple of days ago. I'm glad I bought the SLEC fuselage jig -- never used one before, but it's a joy to see everything clamped into place and perfectly aligned with the guidelines. I can put it to one side while I do something else, without risking knocking something out of shape. Fuselage cnc parts are all assembled and glued, and I'll be getting stringer and sheeting material from my local shop this weekend.

[Martin McIntosh]

Allan, glad to see that you have joined the fray. If you wish to use the sliding battery box idea you must do this before you go any further of course.

A load more pics with text to follow:

[Martin McIntosh]

As you can see from the above this has come on quite a long way since I last posted.

I decided on ARTF style aileron servo mounts but the flap ones just stick out being so small. They are HK 180deg MG type.

The tip lights have been fitted and rightly or wrongly will be strobed with a simple unit as will the tail light. The acetate was formed by gripping a 150mm sq. with heat resistant gloves and heat gunned until it went floppy. This was then forced quickly round the tip, a chunk of balsa chopped out and after drilling the LED and wiring installed.

Watch that you do not melt one during film covering!

Another thing to keep in mind is the elevator joiner which cannot be inserted once the tail cone is in place. I shall have to cut then solder the halves together.

The wings, tail and all flying surfaces have been silver Solarfilmed, the rest being glass skinned. I used the peel ply method on the fus. but not on the nacelles. Amazingly these were very quick to sand with 120 grit production paper (the grey stuff) ready to prime. The primer is Halfrauds brush on, slightly thinned and with a good dollop of baby powder added to make a filler. The first coat was sanded to nearly nothing then another added very thickly and sanded again using 180 grit then 320 to finish. I brushed on a coat of dope thinned 80%, just laying it on the surface so as not to disturb the primer. This helps to prevent the base coat from lifting when masking tape is removed.

The whole operation on the fus. took rather less than a day.

[Martin McIntosh]

I am at a quandry as to the colour scheme. I want it to represent a B Mk.1V but cannot source the correct paint for the chosen aircraft as all places tried either do not sell what I want of are out of stock. The alternative is to do it with a black underside but getting photos of a suitable aircraft is proving difficult. The only ones I can find have bulged bomb doors. I need pics of the actual aeroplane modelled in case it is finished and survives long enough to enter in the club scale comp.

Side viewing panels, exhaust shrouds and air intakes have yet to be made and fitted so there is a long way to go yet.

One thing I forgot to mention was the crew access hatch which comes in handy for getting at the Rx. switch and batteries.

[Allan Bennett]

Thanks for the tips Martin. I've been pondering over whether to glass it, or to use a grey matt film of one of the grey colours, and then paint the other colours over it. I'm a big fan of Lifecolor water based acrylic paints, which come in many military colours, including the ones needed for this model -- light gull grey, dark gull grey, and dark green, if I remember correctly. I'll post later today with confirmation when I find the spec. which I've got in a "safe place" somewhere.

My present thoughts about battery mounting are to make up a complete liteply box, instead of the simple tray that the plan seems to show. Then it can be fitted with the required amount of foam to hold the batteries in place, and a velcro strap over the open end. On the subject of batteries, I don't agree with the suggestion to use a separate one for each motor; better in my opinion to use a single power source -- which may be two in parallel if necessary to get enough mAh -- for the two motors. That way you can guarantee that each motor will be getting the same volts and, hence, run at the same rpm throughout the flight. It also reduces the risk of one motor stopping early because the battery's not charged properly or is too old. I'll also be adding capacitors to the battery leads in accordance with this posting on another forum.

I've never heard of peel ply before but, having looked it up, I'm eager to give it a try. Do you have to brush on more epoxy than normal when using it, or does it somehow draw the epoxy up to the surface to leave it smooth? I'll be adding lighting too, so must remember to install tubes for the wiring before I get too far. What I see on modern aircraft is red/green/white steady non-flashing lights for wingtips and tail, plus white and/or red strobes for visibility. In the past, on non-scale models I've simply used red/green/white strobes, but will take this opportunity to do it "properly" if I can.

[Martin McIntosh]

Thanks. The colours quoted in The Mosquito Explored are Ocean Grey and Medium Sea Grey (Humbrol 106 and 165), the rest being normal dark green or olive drab. Trying to avoid acrylics since I have not had much success with them.

Have you managed to source the correct type of caps for the ESCs? I think that I shall stick with the separate motor packs since the wiring for mine is already looking to be a nightmare. Multi plugs on Vero will be the order of the day and shall post further on this when I get that far.

The peel ply is not my idea but came from Danny Fenton on his 72" Spit thread. Video on page 400 and something I think. Well worth watching if you can find it.

Fit a drawstring for the light wiring since it will likely have a dogleg near the tip. Some marks had two lights per tip and others just one as has mine so just for a better effect I am strobing them.

[Allan Bennett]

You're right about the colours, of course -- I obviously don't remember correctly! LifeColor numbers are UA091, 093, and 094, just in case I can convert you. I like them because they airbrush easily, don't smell, and equipment is easy to clean. I've used them successfully on Solartex, Solarfilm, Solartrim, and Solite after a slight misting with Prymol, and on fibreglass and plastic mouldings after priming with Humbrol plastic primer. I go over them with a Humbrol clear varnish to protect them after finishing.

I got a bunch of capacitors in various capacities from Radio Spares. I haven't gone into the plan deep enough to figure what the wire lengths will be, so what size capacitors are needed, but here's an example of one I've got. Just make sure they're rated at high enough voltage, and that they're low ESR (or impedence). Castle Creations also do capacitor packs just for this purpose which, from their publicity photos, seem to use the same brand as I've got.

I'll also be using multi pin-headers on PCB for the wing wiring connections. I'll use a common "ground" for lights and servos, and a common +ve for the servos, to minimise the number of wires that need connecting. I normally use a separate dedicated BEC to supply my retracts, so that'll require its own +ve lead. For simplicity I think I'll use one light per wingtip, but I'll put two LEDs in it -- one for steady and another for strobe. All of the photos I've found so far have only one.

[Allan Bennett]

That's strange, where's the "edit post" button gone?

In my 11:24:54 post, near the end of the first paragraph, I intended to say ". . . after priming with Halfords plastic primer."

[Chris Barlow]

Still following Martin.

I like the tail wheel assembly. That looks a good workaround to use a "standard" retract.

Shame about the elevator joiner though. Would it be possible to open up a small slot in the tail cone behind the tailplane to pass the joiner through then fill with a slip of balsa afterwards?

[Allan Bennett]

I've come across the elevator joiner "issue" on other models. Having been warned about it, the simple answer is to install it when fixing the tail cone -- just leave it hanging loose until ready to attach the elevators.

[Martin McIntosh]

Bit late now! It would have got all gooed up with resin anyway. If I am not satisfied with the solder joint I shall just have to cut a slot but this is now ready for painting.

In the process of carving the flame guards and there is quite a lot of work involved in getting them to fit.

[Martin McIntosh]

Painting stage nearly there but I had to cut down the rear edge of the intakes to clear the u/c.

The door operation has got me scratching my head as I cannot see how the cam alone can keep them open long enough for the wheels to fully retract. I got this sorted out on the Lanc. I built, with the elastic string holding the doors both open and shut but blowed if I can remember how. I think that piano wire openers similar to the full size could be the answer. lots of the wooden frame parts on the doors could now be removed to make this possible.

Decided on the black underside paint version although I still have not found photos of an aeroplane with exhaust shrouds and single wing tip lights which it could represent. It will have to do.

[Allan Bennett]

From your pictures I can't see how the doors will stay wide enough open either. Rather than a wire contraption, like on the full-size, I might be tempted to install a micro servo to do the opening and closing. Might not be any heavier than the piano wire.

Thinking a bit more though, could a wire rod acting in torsion spring be used to hold them in the open position by default, with the elastic pulling them shut? It could be a piece of piano wire acting in torsion, or a small coiled torsion spring

[Martin McIntosh]

Had a similar problem on the BT one I attempted. There was simply not enough room for servos and they would have required a sequencer. I use one of these in another model. They are tricky to program and need to be armed every time the radio is switched on. Tried torsion bars too but due to the shape of the doors these were impractical.

Will bash on with the door prop idea since this only involves drilling the yoke to fit them and adding thin GF plates for them to act against. These worked fine on the Lanc.

[Allan Bennett]

Yes, I see from one of your earlier photos that there's not much room when the gear's retracted. I've only just started sheeting my fuselage, between finishing the covering on my SE5a, so I won't get to your point in the build for several months yet!

[Martin McIntosh]

Now got the basic paint on. A little re-touching required here and there but quite pleased with the result so far.