Nitro derivatives

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• Slam_Dunc
• salmacis
• cvanscho
• Cardboard Keith

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[thermaled]

Could be a long thread, but thought I would cover the builds of my Nitro based models.
   First one up is Nitro-whee.
Flying my Nitro a couple of weekends ago (fully ballasted at 67ozs), came to the conclusion that I needed a smaller version, easier to launch in a strong wind, ( it was around 50mph on the slope that day),  thinner section and a narower chord to give better speed and penetration for higher-faster stall turns, a Nitro lead sled...but whee.
    Rumour has it that the small and medium sized hills get blown out in strong winds, the wind being to horizontal to sustain flight,  some people tell me its just a ballast thing, you need more lead mate, so this will have a bit of everything.

Wingspan: 1020mm
Wing root :160mm  Tip:100mm 
Wing section : A6014 (thin and low camber)
Target AUW : 42-46ozs to give a wing loading around 35 ozs sq ft
Ballast : about half of AUW so roughly 20-25ozs

 

[Andy_B]

Have you found a pile of cloth to use up matey peeps .........or just itchy fingers

[thermaled]

Better post some pictures. First one is my original Nitro.
Second pic shows the foam cutting templates for the wings, along with a sheet of expanded polystyrene. Couldnt bring myself to use my best blue styrofoam, after allowing for 1mm wing skins the cores are wafer thin. I cut a few spares too.

[thermaled]

Its a new year resolution thing Andy, Not to start any more builds until everything is finished, so got to start them now. Before the new year.

Mark

[thermaled]

I have sheeted the cores with 0.8mm ply, laminated on with 6 oz glass and 6oz uni carbon, should make them tough. Put the lot in my old wing press and left them for a day or so.
 Prepared some mahogany left over from a conservatory for the leading edges, 25mm wide for extra ding resistance. Cut off the trailing edges, ran the wings through the bandsaw to remove 22mm from the leading edge, then stuck on the mahogany with pu glue. It pays to run a strip of tape along the wing leading edge so the pu glue doesnt foam up all over the ply, then wrap about 5  pieces of tape round the wood to hold it all in place. Pictures say it all really.

Mark

[thermaled]

Leave the wings alone for a few days to cure, so on with the fuselage. Waxed and pva mold release applied to my Nitro mold, then stick all the bits of cloth in with epoxy, its a whopper lay up and probably the nose boat will not fit, so have put some extra glass around the inside to strengthen  it as I will be taking it to the belt sander at some stage. I kind of had this in mind when making the molds, its nice to get more than one type of plane from the same mold.

[thermaled]

Wings at this stage are 14ozs, the fuselage is also 14ozs, it has symmetry. Wall thickness on the fuse is around 3mm, should be tough. It will be a one piece plane, will build in some big fillets around the wing / fuse joint to strengthen it for those cartwheel arrivals that I am so good at. Put all the bits together for the first time, will need plenty of surgery and lots of filler, probably a better fin with an aerofoil, but looks ok I think....what do you reckon?

Mark

[MooSey]

That looks nice mark.
Are you gunna sell 'em?
I recently had my first experiences with high winds and poor model response so mini lead sleds sounds cool.

[thermaled]

Making a sled is quite labour intensive, even little ones, so reckon they would work out much to costly to sell. A fuse and wing cores would be an option though.
     You are still welcome to pop over for a visit sometime when you`re passing. Lay up your own fuselage maybe.

Mark

[MooSey]

I can see from your pics it's labour intensive.
If it flies well sell the design to the chinese...........
Looking at your alladins cave im going to have to visit you to pick up some tips etc.
I've lost your Number. if you could pm me it that would be great.

Mike

[thermaled]

Looking at your alladins cave im going to have to visit you to pick up some tips etc.
I've lost your Number. if you could pm me it that would be great.

Mike

PM sent Mike.

[yellowblue]

looks one nice ship, keep us posted on its development

[thermaled]

No more work this year, can get busy building now.
  Planed down the wooden leading edges this afternoon, also flattened off the ply trailing edges with a block plane. Placed them in the foam cores and glued the two halves together. Wing tips are also cut and sanded to planform, will glue them on later tonight. They will need rough shaping with my block plane then the wing will get a good sanding, ready for its top layer of glass.

M

[thermaled]

Gave the wings a good sanding this evening, just got to cut some cloth and bag it now, either tonight or first thing tomorow. It will probably get 2 layers of 6 oz glass, wrap it in peel ply and kitchen paper the vacuum bag it. I want a really good bond between fuse and wing as it will all get stuck together with some chunky wing fillets to strengthen it further, using the peel ply will give me a very good surface to glue.

M

[thermaled]

Have layed up the wing with 6oz cloth,
-one layer all over
-one layer half span on the underside
-one layer half span on top
-one layer quarter span on top
-one layer 6oz carbon on bias 3" wide over wing joint on top

the leading edge and tips have 6oz bias glass 1.5" wrapped around and another 2.5" layer on top of that.

I stuck on the le fabric with spray mount glue, wetted it out with epoxy on a brush. Brushed epoxy all over bottom of wing and placed the pre cut glass fabric onto this, slightly back from the leading edge, largest piece first. Dabbed it all over with epoxy to wet out the scraped off the excess with a thin credit card. Same for the top.

Put a layer of peel ply over top and bottom. ( this is nylon stuff with a coarse weave, epoxy passes through it but does not stick to it).

A couple of layers of kitchen towel top and bottom, put the bundle into a vac bag and suck it dry.

Next day I pulled it out, a suprising amount of epoxy had been soaked up by the kitchen paper, considering I had already gone over the wing with a credit card. The peel ply peeled of easily, leaving a surface with small indentations all over, but very attatched to the ply underneath. The waxy layer that forms on top of epoxy when it cures is ripped off with the peel ply, this is the main reason  have used it, will now get a really good bond between wing and fuse when I do those fillets.

The wing now has a brick like feel to it, after cleaning up and sanding, the wings were 12ozs before bagging, now they are 17ozs, and still need filling and painting.

 Its gonna be an exciting plane to fly 

M

[thermaled]

Scribed out the wing seat today, had to do this because the fuselage is upside down. Cut it out on the band saw then sanded it to a reasonable fit, will wait for my heavy duty low profile servo to come from china before making it a one piece plane, need to make some torque rods too as wings are far too thin for servos.
       
Painted over most of the wing with a polyester based hi build primer, should be able to sand it back over the weekend, then start thinking about cutting out the ailerons.

M