Discussion NEW West Wings BAe Hawk – Pre-production kit test-build

[Gordon]

Hi Guys

West Wings have let me loose on a pre-production kit of their new Hawk. So, because I know that there are LOADS of you out there who’ve been awaiting news on this gem, I thought that I’d post a build and fly report on here just to whet your appetites.

Incidentally I have no vested interest in the design or sales of this kit which is all the work of Peter Shepherd and his team at West Wings. I am really pleased to have the chance to do this test build though, having spent many happy hours as a passenger (with occasional stick-time) in full size Hawks, and also having fond memories of many great flights with a 1:6 scale glow DF version some 12 or so years ago.

West Wings’ Hawk is 35in (890mm) span and 39.75in (1010mm) long, and is designed for 69mm fans. The MF480, Schuebeler DS30 and HET 6409 are all a straight bolt-in fit. I’ll be trying the MF480 with Mega 16EDF (= 16/17/2) for about 330W, and Schubi DS30 with Kontronik FUN480/42 for about 600W using various 3-cell Lipo packs.

Whilst this is not a production kit, I don’t expect that too many changes will have to be made between now and when the kit is released. Design and contents of this kit are to the same high standard as their Hunter kit, and this time it’s been designed for lipos from the outset so there’ll be no balancing problems with this plane.

Admittedly the Hunter didn’t initially get a rave review on the Ezone, not due to any quality issues but entirely because of the installation methods used for the elevator and aileron servos, and also the fact that it was designed before lipos and brushless motors became the power system of choice which then led to CG issues. Forearmed with the complaints surrounding the Hunter, I incorporated sensible yet simple mods in mine which resulted in me producing a super-flying light model which I love to bits and which everyone who sees it in the air falls for too. The mods and the rest of my Hunter build are detailed beginning here in what was initially a quite negative thread about the Hunter.

http://www.rcgroups.com/forums/showt...=368754&page=6

West Wings have learned from their Hunter experience though, and besides updating the Hunter kit have taken care to avoid similar problems arising with this kit.

As with the Hunter, the Hawk’s structure is predominately balsa with birch ply formers and ribs, with vac-formed styrene nosecone and internal ducting. The fuselage side panels are vac-formed styrene too. The wings are all-sheet covered this time, and not D-box like the Hunter.

A note on the use of ply is in order as the fuselage formers and wing ribs are cut from 1/16in birch ply for a good reason. This material can be fretted out using CNC machinery to more slender profiles than liteply or balsa, and the components demonstrate significantly higher strength than liteply and balsa with a minimal weight penalty. I proved this to myself with my Hunter build which surprised me with its lightness, so expect the Hawk to come out at an acceptable weight too.

Photo 01 shows the kit contents. The balsa in West Wings kits is truly marvellous stuff, and the rolled full size plan is very clear.

[imodel]

Signed on for this one!

[Gordon]

Before removing the pre-cut parts from their respective sheets, it’s a good idea to label them in pencil with reference to the component identification sheet supplied. I covered the plan with waxed paper before gluing any parts.

Ducting

It’s advisable to construct all the ducting before starting on the fuselage so that the adhesive is hardened and the intake and nozzle ducts are then available for installation at the appropriate time during main fuselage assembly.

The assembly sequence is shown in a separate Ducting Assembly sheet (photo 02a). To remove excess plastic from the edges of the mouldings, I found it best to lay a moulding on the workbench, duct uppermost and moulding waste flat to the bench. Then I lightly drew a sharp knife blade along the inside of the corner several times to score the plastic, not allowing the blade to wander. Picking up the moulding and flexing the waste several times caused the waste to break away from the ducting. I then dressed the edges of the mouldings with fine sandpaper.

Photo 2b shows how I clamped the upper and lower intake duct halves together, before carefully painting liquid polystyrene glue along the joints, and allow the item plenty of time to dry. When the glue was dry, I ran thin CA along the joint and shot this with accelerator to ensure the joint was fully sealed.

After assembling the two duct halves, which incidentally are not “handed”, you glue a 0.4mm plywood plate to the flat inboard side as a stiffener. A 1/8in diameter hole is drilled in the top of each duct just ahead of where the flat back wall forms the vertical knife-edge, so that the fan can draw cooling air over the esc via the upper fuselage air scoops. Photo 3 shows the completed ducts ready for installation when the time comes.

[Gordon]

Hi imodel - that was quick Welcome!!

Fuselage Nose Section

The next item for attention is the nose cone section, for which you assemble a framework, onto which are glued vac-formed skins.

Only the left-hand elevation of the framework is shown on the plan. The assembly sequence is to first build the left-hand framework over the plan, lift it off the plan, and assemble the right-hand nose section framework on the left side. This is achieved by clamping the right-hand keel pieces to left-hand ones, with a piece of waxed paper in between to prevent these parts being glued to the first half-shell at this stage.

When the glue has set, the two half-frameworks are separated for the addition of their plastic mouldings. You first bevel the edges of each framework using a sanding block, paying particular attention at the nose end back to F1, so that when a framework is inserted into its matching moulding, it can be pushed all the way forward. Next you draw round the periphery of the framework inside its moulding in pencil, and then cut the moulding from the vac-formed sheet leaving a small overlap (4-5mm) all round.

Each moulding is glued to its framework, for which I used Evostik as the adhesive. I squeezed a good bead of the glue onto all the edges of the framework and pressed the framework into its moulding whilst the glue was still liquid, holding the edges together until the glue grabbed, which wasn’t long. Before gluing, the moulding will fit its framework more closely at the edges if you roll its edges inwards carefully without creasing, so that the edges self-clamp against the top and bottom keels.

After trimming the mouldings, you sand the jointing faces of the left and right-hand nose sections, and I decided that it was best not to glue them together at this point as they could be used to jig the adjoining F4 in the main fuselage to an accurate matching fit.

Photo 04 shows this work in progress.

[Gordon]

Main fuselage

The whole left side framework from F4 to F15 is first constructed over the plan as seen in Photo 05.

I found it necessary to CA small pin-blocks to F8, F9, F10 and F11 as in Photo 6, pinning these to the building board to stabilise the formers whilst the stringers and other pre-shaped side-pieces were added. See Photo 06.

To ensure that F4 would lie be snug with F3, I offered the left-hand half of the nose cone up to support F4 in alignment.

Before adding the wing saddle piece, F16, this part needed to be given a permanent curve in plan view before it is glued in place. This was achieved by gently pressing F16 down onto the workbench and stroking it a pen barrel, at the same time pulling and lifting the rear end of F16 until the whole piece took on the correctly bowed plan view to fit between F8 and F11 with no strain before gluing in place. Photo 07 shows how I achieved the bending.

When this assembly was completely set, I glued the left-hand half of the nosecone in place. Then I sheeted the entire fuselage 1/2-framework, including the vac-formed side panel and the 3mm balsa boundary layer diverter – see Photo 08

[Gordon]

On removing the assembly from the building board I laid the left-hand intake duct inside this fuselage half to check its fit, trimming away the formers as needed. I left the ducting inside this fuselage half but not glued in place.

At this point it was sensible to assemble plank and sand smooth the forward intake fairings sans intake lips but not add them permanently until they and the fuselage have been covered with tissue/sanding sealer or glass/epoxy, etc. The fairings are in Photo 09

Fitting the fairings and trimming the ducting needs doing in a definite sequence. With the left-hand fuselage framework flat on the board, I slid the intake fairing over the front of the intake ducting and ensured that the fairing sat square with the boundary layer splitter and F8. The aperture in A2, and A1 adjacent to where it meets A3 needed trimming back with blade and sandpaper to clear the ducting and allow the fairing to seat correctly – Photo 10.

Once satisfied with the fit of the fairing over the ducting and against the fuselage, I trimmed off the ducting flush with the front of the fairing. To enable the ducting to slide into the front fairing former easily, I bevelled the outer leading edge of the duct and the inside of the fairing former so that it slid easily over the ducting.

The next job is to glue the intake lip to the fairing and round off its leading-edge to an aerofoil shape. The inner edge is shaped by removing the intake duct from the fuselage, inserting it into the fairing and holding it against the back of the lip, and then trimming and sanding the lip flush with duct’s inner surface – Photo 11.

Once this is done, you put the ducting back inside the fuselage half, slide the fairing over it, and sand the fairing flush with the moulded side panel, using the ducting to help to steady the fairing in position. Then you remove fairing and duct until later, labelling the duct as the left-hand side item.

[Gordon]

Photo 12 shows the near-scale boundary layer splitter, and Photo 13 has the intake ducting protruding, to be covered by the fairing as shown in Photo 14. This is about the nearest you can get to a scale intake arrangement for a Hawk at this size, bearing in mind the breathing requirements of the EDF unit. West Wings have done a supreme job here in faithfully maintaining one of the most characteristic features of the Hawk.

[Gordon]

Now is the time to construct the right-hand fuselage framework and skin it. Unlike the Hunter plan, the Hawk plan does not carry a mirror-image of the fuselage structure. I can’t say that I’m keen on this feature which results from limited paper size and the need to control the final price, but there it is. There are 3 ways of addressing this arrangement.

First, using a pad of kitchen roll dipped in cooking oil, gently rub the oil sparingly over the rear of the plan to make it translucent so the framework shows through, and build the structure on that.

Second and this is the system the designer intended, use the left-side of the fuselage as the “plan” and assemble the right-hand framework on it, removing the framework to be pinned to the building board for sheeting. The left and right-hand fuselage halves would subsequently be glued together.

Third, which is what I did by mistake because I misunderstood Peter’s intentions whilst discussing it on the ‘phone with him (there were no written instructions at this stage), assemble the right-hand framework firmly glued to the left-hand side.

I did have misgivings about doing this but went ahead anyway, only discovering my misunderstanding in a later chat with Peter after I’d built the fuselage as far as shown in Photo 15.

As I’d suspected would happen, the rear of the fuselage as seen in Photo 15 ended up misaligned. However, I easily corrected this fault by tack-gluing a 2in wide strip of 3/16in balsa across the wing aperture as seen in Photo 16 to force the fuselage into alignment – it was only a little bit out anyway. After gluing the jig in place, and before completely sheeting this side, I added the esc plate complete with Velcro glued on, and the elevator snake outer.

After adding most of the right-hand sheeting, the next item on the agenda was to drill the vertical hole for the 3mm launch pin tube adjacent to the bottom of F7, and epoxy it in place along with its plywood gusset coating the whole area liberally with the glue to strengthen it. I didn’t fit the battery tray at this stage as I wanted to ensure that it would end up in the right place to mount every different 3S battery I would be using.

Photo 17 shows most of the right-hand sheeting in place, the esc location for which cooling air will be available via scale air scoops, and Photos 18 and 19 show the temporary dry fitting of the ducting and fan unit..

I must say that it’s a very clever design and assembly has been a breeze, even though I did stray from the recommended procedure for making the fuselage.

That’s all for now folks! I’ll be tackling the flying surfaces next.

Gordon

[Robert Belluomini]

Gordon,
I see you have been keeping your hands busy while waiting for your large Hawk to arrive! Great build you have going there.
Bob

[Gordon]

Thanks Bob! My large Hawk should be on its way here from Thailand by now.

[Synwpn]

great work Gordon! Something about building in balsa always gets me interested!

[bobthenuke]

My feelings too, Gordon...beautiful work. I still have a WW Hawker Hunter in the box that I'm itching to get to some day. I love the quality of the kits from these people and this one seems to be every bit as nice. It'll be interesting to find how much it'll cost by the time it reaches our shores.

...bob

[hammo6]

Logging on to this one, I agree balsa bashing is very rewarding especially when it is a jet!

..David

[imodel]

Hi imodel - that was quick Welcome!!

The Hawk has been a fav of mine, just waiting for the right model to come along. Looks like the wait is over!

Cheers!

[WeMoTec]

So far I was under the impression, that this project would be kept secret until it is finally available.
Since I really hate this vapourware threads, I just hope that this kit becomes reality in reasonable time.
My information is, that the first shipment shouldbe available in about 2-3 months from now.

Oliver