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Mossie


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Well that`s much of the easy bits done so the fun really starts now with the nacelles.

I studied the build photos for quite some time before committing the bits to glue, particularly N4 as to which way round it goes. The long side is of course towards the wing tip. I propped up NA2 with 1/2" wood to clear the bench then fitted N3 followed by N2. I then added NA1, checking carefully for squareness and finally N4. The build instructions seem a bit out of sequence at this point because it is obvious that the retract mount and reinforcement pieces must be fitted at this stage. I added 3/8 sq. spruce to N2 to stop the motor from flying off. Initially the parts were tacked in place with thin CA then the joints run over with thicker stuff. Much better than trying to hold everything in place while epoxy sets, and being liteply CA takes well to it.

Don`t forget to fit the motor mount captive nuts before starting assembly.

The retract plate needed narrowing a little and the captive nuts adding before fitting. I trial assembly was then done.

The nacelles were offered to the wings and after a bit of chamfering to clear the excess spar glue fitted well. I have not actually glued them in place as yet.

I am going to use Perkins spinners but had not realised that all four nose screws cannot be fitted when they are cut for a three bladed prop. Should be OK though.

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Glad to have you with us Andrew. Hope that I do not lead you on the wrong track.

Got the nacelle sides NA3&4 on now. I soaked them in soapy water after tacking to N2-4 and left them for an hour or so before glueing the rest after a bit of heat gun treatment. N1 will not be fitted until the motor has been reinstalled in order to align the spinner. The rear former angles were set with a card template under W3.

Looks like I do not need to make glass cowls after all since the motors can be accessed from the front.

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Will try it on the nacelle sheeting which is next.

Found one or two problems . The top wing sheeting cut out for these seems to be incorrect since it leaves nothing to glue N9 to. Better to cut as shown on the build pics in my veiw. I had to add some support pieces here. I have not as yet fitted the wing LE`s and there will be a gap now between the inner edges and NA2 which I shall have to sort out. The Perkins spinners have a slighty smaller diameter (3.5" than those shown on the plan so if you use these you will need to reduce the dia. of N1 slightly. I just do not trust myself to make up ABS spinners for motors as powerful as these.

I fitted Velcro for the ESC`s before adding the nacelle longerons. The wiring to the motors from these may need extending a little.

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My plan and parts haven't arrived yet, so I don't know what TN recommends for ESC placement. But bear in mind that it's safe to extend motor-to-ESC wiring as far as you want, but if you extend battery-to-ESC wires you need to install extra capacitors between the + and - wires to avoid long term damage to the ESC. There's a long article about the issue here.

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Thanks Allan, I have had a quick look at that.

The nacelle fronts have now been sheeted. This has taken all weekend and was by far the most difficult job to date, ammonia or not. I ended up part sheeting, part planking these, which have been roughly sanded with the spinner backplates in place. Not sure about those projecting pieces at the front of the doors but I expect this part to become clearer when I come to make them.

mossie.jpg

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Been doing the rear nacelle sheeting. This was entertaining but I did not find it too much fun at the time. In the end I cheated and laminated two layers of 1/16 for each piece.

The protruding bits at the front were tamed with ammonia and were actually quite easy to pull together.

Be warned that if you think cyano fumes are bad enough then although this stuff curls balsa it will also curl your hair, ears, eyes, nose and probably any other part of your anatomy.

Here are some pics of these bits roughly sanded. Quite pleased with the results so far.

Even though I cut the main parts myself I feel that much of the rest requires the use of a scroll saw so if you do not have one then put it at the top of your Christmas list. Pretty cheap from Axminster Tools.

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mossie 018.jpgmossie 013.jpg

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Looks like fun! When I built the Ellipse I also laminated 2 pieces of balsa for the wing root leading edge to get the required curve!

How bad is the ammonia soaked balsa after it has dried? Wouldn't want it stinking out the shed for weeks afterwards or having a model that forever smells like the cat pee'd on it!

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I have encountered a major problem. The wheels do not fit. Despite the fact that my u/c legs are at least no longer from the pivot point to the outer edge of the wheels I have had to cut some material from the rear of the retract bay. The worst bit is that the doors cannot close over the wheels despite the fact that they touch the upper wing sheeting. All measurements have been checked in triplicate so what do I do?

I have decided to try to make GF doors using one pair to make a mould. Making these the tradIitional way would be very time consuming so I dug out my old Heath Robinson vac form thingy and added some balsa to the edges of a set of doors to attempt to form an acetate mould for some super thin ones. If this works I shall probably have to make these again for the other side. Currently coating the acetate with release wax in preparation for the gel coat.

The best way round this problem would be to obtain some 4.5" wheels but these are scarse.

The wheels I have (125mm) were for the 1/8 scale BT version so maybe this size is too large for this anyway.

Anyone else got this far who could provide some advice?

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Thanks Danny. The `test fly` wheels are very light foam with a square section and the ones I eventually intend to use are rounded but heavier. Neither fit. Thought about reducing them and have been told that by freezing first they can be turned down more easily. My point is that these should have fitted anyway. If the GF does not work for any reason I shall try that.

Had the same problem with my TN Spit but got them in somehow.dont know

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I do not expect the square section test wheels to fit as they are, even with GF doors but have ordered more 1/2" alloy to modify the yoke for the rounded ones. Its just that the former are very light and would help with the cg.

If I still have a problem I shall prop up the rear of the nacelle sides with tapered balsa and re-profile the back end to match. Couple of days to wait due to GF setting time.

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