1/5th Hurricane

[Kevin Turland]

Hi, I'm looking for some help and advice. The model I am on with at the moment is the Vailly Aviation Hurricane which as per the plan has a one piece detachable wing. I want to change the design to allow me to have a permanent root section mounted to the fuselage and then the wings will 'plug' in to the centre section. There are two reasons for this alteration the first is that the model will be eaier to transport, the second, and most important, is that I plan on using a MVVS 58cc liquid cooled engine, this will enable me to keep the cowl free of unsightly holes that the original didn't have by mounting the radiator in the glass scoop under the fuselage. I have designed and made (partially) working exhaust stacks as per the original as well.

So, chaps, to make the model I need some schematics on how to make the 'plug' in wing surfaces good enough to stand the forces a 28-30lb all up weight model in flight. I've only ever built one piece wing models before.

Thanks
Kevin (2956)

[Phil Clark]

On a model of this size, the 'tube' method of joining is probably the best option and easiest to build into what was a 1 piece wing................

High grade aluminium tube joiners are available that come with a matching 'phenolic' outer sleeve......these are (should be....some a better quality than others) a snug sliding fit with no slop. I'd suggest having one tube around the conventional 'main spar' area, and a 2nd smaller diameter one further back to act as a rear spar joiner/incidence peg

With the relatively flat wing of the Hurri, you could have 1 continuous tube passing right through the centre section (as long as you can uy a long enough tube) passing 10/12" out into each outer panel, with 2 smaller tubes for the rear joiner.

For diameter, I'd go for around 1 1/2" for the main and around 1/2 to 3/4" for the rear. These tubes ideally need to pass through birch ply ribs (or lite ply ones with birch 'washers' to locally strengthen). The tubes don't specifically need to be tied directly into the conventional timber spar structure (you try pulling a 1 1/2" da tube through multiple ply ribs in shear!!!!)....but if you can, so much the better

Attached below are a couple of pics of a tube joined wing for a 115" Sea Fury we're currently building................using exactly the principle I've mentioned.

Hope this helps.............

Phil

[Mike Booth]

Phil is completely right of course in what he says, however, you could save yourself a fair amount of weight by using a carbon tube joiner slid into its own purpose made liner.
You would be surprised at just how little length of tube you need, to create the join between fuselage and wing as long as it is incoporated into the mainspar and not beside it.

The carbon tubes i use are bullet proof, with only a 1.5 mm wall thickness.
The outer is very thin and because they are honed, there is a perfect fit between the two.
I would suggest that if using carbon, you would not need a tube which is more than 25mm in diameter.

Talk to Colin Skene at Hardy and Greys Ltd 01665 602771 and tell him I sent you.
I have my tubes made , however you can buy from a selection of stock lengths and diameters.
When he qoutes you a price just think of the weight saving, accuracy over other methods and the fact that you are only going to build it once, so its moneny well spent.

Mike.

[Mike Booth]

Sorry thats meant to read 'no more than 25mm' on the above post.
Mike.

[Phil Clark]

Carbon is great (but my god it's expensive having gone down that route in the past myself).......so why not buy the best quality aluminium joiner and phenolic sockets available and the weight difference will be negligable. The tubes I bring in from a company in Germany are of an aircraft grade aluminium with a 1mm wall thickness with a hard anodised outer surface.

As a guide, a 25mm tube with phenolic outer socket in a 1m length weights just over 300g

Kevin - To answer the question you e-mailed me regarding retaining the outer panel onto the centre section......I fit a 'tongue' to the outer panel, and this slides into a box containing a 'T' nut in the inside face of the end rib of the centre section......you have to make sure the tongue is aligned in exactly the same plane as the 2 tubes so when you slide the panel on, the tongue engages perfectly in it's box. This is then retaned with a small bolt from the underside of the centre section....

Some people like drilling & tapping the tube itelf to use a small retaning bolt.......problem here is drilling the tube weakens it, and with the type of tube I use with such thin walls, tapping is next to impossible, especially if you want the thread to last any length of time.

Phil

[BRIAN RAWCLIFFE]

Hi Kevin
I built the Vailly Aviation Hurricane about 7 years ago and it is a wonderful model to fly.
My method of doing the wings is different to what you are proposing, I made mine into a 2 piece wing joined with blade and brass box wing joiners which were obtained from Gliders.
The engine was a Mackay 45cc front induction turning a 22"by10" prop. Like you I wanted a clean cowl i.e. nothing hanging out. To allow me to do this I made a prop driver extension approx 1" long so that the engine could be moved to the deeper part of the cowl, and by doing this the top of the plug cap was just about flush with the inside of the cowl bottom.
I fabricated a manifold and silencer box out of thin mild steel plate and all this fitted inside the cowl with only the 15mm diameter stub outlet showing.
The weight of the finished model was 28 1/2 pounds and the 45cc had stacks of power, and it was a joy to fly.
If you go on to Stuart Mackays website http://www.moki.co.uk/mackay then click on to pilots de-brief and scroll down to the last picture, that was my Hurricane.
To me any one piece wing over 72" is a pain in the backside, so all my models are converted to 2 piece joined in the method above.
These include the Hurricane,my 1/4 scale Chipmunk,my 1/4 scale PT19, my 42% scale Chilton DW1A, my Vailley Aviation 1/5th scale Tempest M11 and my 1/5 scale MK1 Flying Legends Spitfire, still performing wonderfully after 11 years.
If you are reading this Mike thank you for producing such a great model aeroplane.
P>S> Phil if you are reading this I understand the new addition is a boy - congratulations to you and your wife, and dont forget to start him on free flight and then galloping ghost.
Brian LMA1669 (See you all at Cosford)

[Mike Booth]

Its a pleasure Brian, fortunately I have had many say the same thing.
I remember clearly a chat with you on Boxing day one year way back in the 1990s.
Maybe you would like to try the new 1/4 scale MK 9 Spitfire.

Regards Mike.

[Phil Clark]

Thanks Brian........I've got him woring on the cockpit detail of a 1/4 Sea Fury already......he's only little, so fits inside really well