JW (Joseph Wurtz) 60 DS Foam Flying Wing

[Peter Garsden]

I got £100 for Christmas from my mother-in-law and put it towards a JW DS Soarer as I have just discovered Rushup Edge and DS'ing, not that I can do it, but I need a proper plane to practise with. I tried the SAS Fusion, but it was not really fit for purpose.

The box arrived about 3 weeks ago, but I have been finishing the Jart.

Got it out the box this morning (again), and these are the contents.

[Peter Garsden]

After speaking to Jules who has an Odyssey that weighs as much as a church roof, I decided to make this stiffer and ballastable (is there such a word?)

I have a spare 10mm sold carbon rod left over from the Jart so will put it to good use - should stiffen up the wing. I have also bought a 20mm carbon ballast tube which will take 10 x 35mm slugs - or an extra 1200grams!

In addition to the 2 x 6mm carbon tube you can see which go top and bottom of the wing, I might replace the trailing edge sub spar with carbon rather than basswood as per the Pro Version which I nearly got.

Made a start by epoxying the rods into the aluminium joiners. Will do the same with the carbon rod by cutting it in 2 then joining it with wraps of carbon tape.

[Andy Meade]

Very nice Pete. I'd like to get a DS foamie to try it out before committing my carbon Blade to some circuits.

[Peter Garsden]

T9 are selling them Andy.

[Peter Garsden]

Have now inserted the carbon rods, top and bottom as well as the ballast tube. I used gorilla glue rather than goop as this was recommended by Andy Ellison as being easier to work with. It also sands flat better.

So I have doubled the number of support rods at the wing centre by adding the 10mm solid carbon rod. I have also used the basswood spars which were intended as trailing edges in the existing slots. The photo explains.

I am using a carbon square hollow rod 6mm x 6mm trailing edge instead of the bass wood. This is the spec for the upgraded version.

I have made a slot in the ballast tube to insert either lead or wooden blanks as necessary. I will have to replace the round headed bolt with a counter-sinked version to avoid it sticking above the surface of the wing.

[Peter Garsden]

The kit specifies that you use 1/4 x 1/8 basswood strips for the trailing edge of the wing. I used these to filll the slots in the wings as additional spars. I now have 4 spars instead of 2 to make the wing more rigid, so I decided to use square hollow carbon spars which I found measuring 1/4 x 1/4

So I cut the spars to size - two long spars for the wings and a short piece for the short flat piece under the fuselage. What glue to use - I was going to use Aliphatic Resin, but that is really for wood. So I opted for Gorilla Glue and taped the spars in place.

I have also decided to use up 2 thin wing servos for the Elevons. Hopefully these won't pack up as other similar Hitec HS125mg have done. Hopefully not? I am going to line the foam wing cut outs with epoxy mixed with microballoons protected with cling film. I might then drilll holes in the epoxy and secure the servos that way.

[Peter Garsden]

I sanded smooth the carbon trailing edges which stiffened up the back of the wing nicely.

Next job was to install the servos and receiver. Holes have to be cut in the wing to accomodate them. The instructions mention Goop, but I don't have any

I cut the lines for the wire and the outline of the servo holes with an exacto knife. I then dug out the holes with my hot wire pen, which is driven by my 12 volt transmitter. It is so handy. I then did the same for the receiver and checked the direction of the servos.

I am going to epoxy a think layer below the servo, insert some cling film then press in the servo to make it a tight fit.

[Peter Garsden]

The servo holes are now lined with epoxy mixed with microballoons. It was a bit tricky getting them out, and I broke off one of the tabs, which is not a problem as they are such a tight fit now. I am planning to drill small holes through the tabs into the epoxy and screw the servos down to make them extra rigid.

I was advised to apply spackle to the surface of the wing. Instead I just bought some lightweight filler and applied it to the top and bottom with an unwanted old credit care. The problem is that it is flexible and not really sandable, definitely an improvement though.

Next step is to make servo extension wires and a battery extension wires, then cover the wing with clear laminating film. The instructions suggested clear tape, but clear film is more consistent.

Edited By Peter Garsden on 03/04/2016 22:21:29

[Peter Garsden]

The laminating film went on OK, but I had to make sure I didn't melt it with the iron, which was on too high at 150 degrees C.

The foam didn't melt under the covering. I tried for the first time the very cheap Hobby King covering to see what it was like - very good actually, not substandard at all, went on very well. Decided to cover the top and bottom of the wing differently, and used red and white check underneath

I applied masking tape to attach one of the ailerons temporarily as one cannot slide the fuselage over the wing when both are attached.

The other aileron is attached using a type of hinge I had not seen before and is great. One applies some good quality clear 2 inch wide tape to the underneath half on half off the wing. One then wedges some small pieces of coroplast to the tape as spacers followed by the aileron wedged up against it. One then takes out the coroplast, and applies another piece of clear tape to the top. Then one runs a finger and thumb up and down the tape, then push in the aileron to join the two pieces of tape together and to create a very effective and free hinge.

[Peter Garsden]

For the top of the wing I decided upon a Union Jack. The fuselage will be the vertical red stripe.

I found a diagram on the Net of the dimensions and proportions of the stripes and lines.

I used to old file covers and taped them together with masking tape. I used the same dimensions and drew some lines on the cardboard. I then cut out the lines so I could draw round the shapes, and line up the gaps to have them in the right position.

[Peter Garsden]

Last night I got a pass out because there was nothing on the telly, so I made a hole for the battery in the nose of the fuselage, and made it deep enough so that a piece of 3/16" balsa could be used to protect it - the recommendation was coroplast, but I don't have any.

I made holes for the wires with a sharpened 6mm brass tube, which I used for the blue foam Jart wing. Worked well. I filed them out slightly to take the width of the female JR plug. I am using a magnetic switch from T9 Hobby Sport rather than the plug in system advocated in the instructions. Just as well because the leads would not have been long enough. I read that one should have a plug and socket where the wing meets the fuselage in case one has a fuselage rip off situation in a heavy landing. I used a piece of wire out of a cable tie to hold it together and avoid an unintentional parting.

I covered the fuselage and fin in red solarfilm but managed to heat shrink a warp into the fin. Hopefully heat will shrink that one back as it is a hell of a warp. After all it is only coroplast. Unfortunately I have glued the fin in place now with Gorilla Glue, so it will be a bit tricky.

You can see in this picture, the magnet one uses to switch on and off, as well as the charging lead, which will be taped down for flight and just connected for charging, hopefully.

RULE BRITANNIA!

To finish this off, I need to connect up the right elevon, make up the linkages, and balance it out. So maybe will maiden this weekend?

[Andy Meade]

Good grief - are you bringing any PSS this weekend Pete?!

[Peter Garsden]

Oh yes Andy, I will be replete with PSS - will bring one none PSS just for fun - could be the Jart or might be this one - we will see. For the record I will have

1. Vulcan
2. Alpha Jet
3. Tornado
4. Hawk
5. JP

Not had time for bombs unfortunately.

Think I need 7 hands a push trolley?

[Peter Garsden]

Well the JW is now ready for its maiden flight - the Orme? It needed quite a lot of lead in the nose - I think that was because I used carbon square hollow 6mm for the trailing edge of the wing which was heavier than the bass wood specified, also the extra 10mm carbon rod as extra stiffener.

Just thought finally I would show you my tools for moulding lead into shapes.

1. I made a plug out of balsa.
2. I made an impression of it into my plant pot full of wet sand
3. I melted the lead in an old tin can on the gas hob. and poured into the sand mould

[Peter Garsden]

Just worked out the wing area - 1/2Span x root chord + tip chord and it comes to 4.114 square feef and it weighs 50oz, unballasted so the wing loading is 12.15oz per sq foot, which is very respectable. Should go up in a light breeze though it isn't a lightweight by any means.

The ballast weighs 37oz so the wing loading would go up to 21oz per square foot - more like a howling gale fully ballasted then - sounds good to me.

[Peter Garsden]

Deliberate error No1 - Matt Jones pointed out that my Union Jack stripes are in the wrong place - sickeningly, he is right of course, but I am not going to change it now.

Deliberate error No2 - Bob pointed out that my right aileron was slightly warped where I had applied the 3M tape, and as such was acting like a flap - will have to redo it, as it flies so fast.

At the Orme yesterday, I maidened it. I expected it to sail away, but surprisingly it kept bobbing its head like one of the those annoying flowers they used to sell in the 60's.

Bob Jennings and a friend of Tim Mackie's came to the rescue. It seemed as though it had a mind of its own, so we set about doing some test glides. It wanted to stall all the time. Flying wings are well known for being very sensitive on C of G, which seemed very far forward as it was to me.

We experimented with weight in the tail which made it worse, then we put some in the nose, which made things a lot better. The transformation was amazing and soon the wing was screaming round the sky.

I can see why it is good for DS'ing as when I was trying to circle round for a landing it seemed to speed up as though I was on the back side of the slope. No crow brakes, so one just has to dump it where you can.

After doing a glide test it rose up on its own which means a little less weight in the nose, but all in all a very fast and satisfying machine.

I had too much elevator movement, which made it too twitchy, so I adjusted that back. Still too much for DS'ing though, even with 50% Expo.

I must admit I am surprised that it needs so much adjustment.

Edited By Peter Garsden on 17/04/2016 07:19:36

[Peter Garsden]

To keep you up to date with flying, this model is definitely better at those fast loops than front side flying. It is made for DS and I would imagine it is very good at it - not that I have yet been up to Rushup Edge with it.

I experimented with 4 slugs of ballast in the tube and it flew like a sling shot that was impossible to slow down for landing.

Yesterday I got it out to fly at the Orme, and one of the HS125MG Slim Wing Servos wouldn't stop chattering. The other was fine. It mystifies me why that should happen. It is not as though there was any excess strain. The servo did not respond to any input and seemed to move all on its own.

Has anyone any idea or experience of something similar. I am sure this is not the first time one of these servos has packed up.

I think it is still under guarantee but I have bought so many of these, that I cannot track it down to a particular vendor.