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Mark's TN Hawk Build


Mark Elen
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Hi Gary,

The EDF I have is one which comes up on offer from HK from time to time. It is a 10S unit so needs much heavier batteries. I already had a pair of Zippy Compact 5800 5S. Would prefer Multistar ones but they do not make 5S packs. Also would have preferred an 8S fan but I only paid £44 for the one I have.

The HK site has been changed again and no longer lets you see previous orders so have no idea what the product code is. You would be better using 8S anyway.

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  • 4 months later...

At long last, I've made a start on this build. Just for a change and because I've never built a wing with jig tabs, I've started on the wing first.

The quality of the laser cutting and routed bits in the CNC kit is excellent.

I started by getting both sheets of the plan photocopied, with 2 copies of the wing plan - 1 a straight copy, the other a mirror image. It's strange that Tony has drawn the wing twice on the plan, but they are both the same wing (one shown in detail and one shown fully sheeted. Or is it just me not reading the plan correctly??😁

Anyway, by doing the photocopy, it means I can cut the plan up and fit it to my board and not make a mess of the original

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Cheers

Mark

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A bit more done last night. I ran out of 'square things' to use for holding the ribs square.

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I found that I needed some packing at the bottom of W1 to space it off the board and keep it all lined up. Also, the CNC cutting of D1 (the dihedral brace) had the sides square with the flat top edge, on trial fitting there was a bit of head scratching as to why it wouldn't fit neatly to W2. It was a little too long as well. My Proxxon sander soon had it to the correct length and square to the bottom edges.

Cheers

Mark

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A bit more done over the weekend, in places, I've gone a bit 'off piste'. Maybe a little OTT, but it has kept me busy. I've fettled the stub spars into the main spars and also the webbing. The plan is a little vague as to where the light ply webbing goes, at one point saying up to w3 on the fronts, but at the other end, it says 3mm hard balsa from W4 to w9. That leaves the backs of the central section and the whole of bay W3-W4 to interpret.

As the stub spars terminate into the back of W2-W3 and the retract bearers terminate into W3-W4, I decided to use light ply for all of the central section up to w4.

I also made a mistake getting a hole in the wrong place😁

I made up the front false l.e and the t.e so that they both extend to the board. This will allow me to pin the wing flat to the board whilst skinning the top.

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Cheers

Mark

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Hi Mark,

I thought you wrote that your next build was going to be a 'quick & easy one' just to keep busy till October when the Fury Class opens... cool

And now, sjeesh... such a complicated lay-out. Just looking at your pics, I could very easily get dizzy... and that's just half-a-wing. surprise

I can't promise I'll be there if you feel like a mojo-issue coming up. But at least, I subscribed now. yes

Cheers

Chris

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Hi all,

Second wing panel is now done and sheeted on the top

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The other side sheet is on the board with the glue drying. I cut out the sheet so that it is 1/2" oversize all around except for the root edge. I have left this a few mm so that I can fettle the fit to the sheet that is already on.

I'm glad now that I extended the l.e. And t.e. Pieces down to the board, as I have been using these to pin the wing panel flat to the board whilst the sheeting is progressing. I also cut up a piece of 1/2" to 40mm to pin the tip that wasn't being sheeted to.

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Cheers

Mark

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Bearers are now all done, the bottom now needs sanding and the jig tabs removing. I had to move the aileron servos nearer to the spar as in the position shown on the plan, they were fouling the underside of the top sheeting. I have formulated a plan for marking out all of the holes to cut in the bottom sheeting when it's fitted, more on this later.

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Cheers

Mark

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Thanks Gents👍

Geoff, those retracts are the ones from Tony Nijhuis Designs. I don't know if I dreamt it, but I seem to think I read somewhere that they are HK units with some modifications. One thing they are is heavy. 135 g (just over 5oz)each, I'm getting a bit concerned at how heavy the wing feels with all of the bits attached.

I was hoping to bring this in at less than 4.5kg (9.9 lbs) to give a 1:1 power to weight ratio with the fan, but it is not looking likely. I can't recall what weight Tony managed with the prototype.

Cheers

Mark

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I had a look this afternoon and Tony's came out at just over 9lbs, that's given me something to aim at. Tonight's activities, apart from sanding and cutting out sheeting, I started looking at how I'm going to cut the bottom sheeting in the right place for the servos and retracts. Unfortunately, the retracts and the plan don't match very well (I had to open up W2 a fair bit to get the wheel to fit)

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So I traced the retract onto some scrap 1/16 ply and gave it a bit of 'wiggle room'

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The plan is to cut this out with the fretsaw then use this as the jig to cut the sheeting. I don't like cutting with a scalpel on the 'good side' so I may have a rethink and make a jig so that if the scalpel slips, it is into the scrap that is coming out. I can think some more on this tomorrow while I'm working.

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Cheers

Mark

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Hi all,

I didn't get a lot of time tonight, but I made a lot of progress with what little I had. I've been mulling over making a cradle to sheet the underside of the wings to keep it straight and true.

I made an upgrade to my workshop before Christmas of a Proxxon Scroll Saw, but it has not been out of its box until recently. The old scroll saw was a B&Q cheapie, but it was pretty poor. Couldn't keep a straight line, let alone keep it true in the horizontal plane. Wow, just wow. The photos will do the talking. None of these have had any sanding or any other intervention, just straight from the saw.

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The 2 blocks of 1/2" for the tips were pinned together and put through the saw as a 1" thick block. I'm very happy with the accuracy.

Cheers

Mark

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A bit more done today. Finished making the hole jig for the retract cut outs, got one side sheeted and the retract hole cut. It worked a treat. I made the blocks up to be a snug fit between the retract bearers and glued them onto the jig with superphatic. I also used a scrap block pushed onto the needle file to stop me from poking it through the top skin.

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Cheers

Mark

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Managed to get an hour in tonight, but no photos to show. I've got the last skin on the board drying and I also got the airbrush out and put a coat of Mr Hobby Primer and Surfacer on a couple of the mini servo mounts.

I'm going for the Red Arrows Scheme, so the plan is to use Vallejo model air red and see how it matches up to the Hobby King Red covering I got for this.

I also got a bottle of black and a bottle of white so that I can go darker or lighter depending on how close the match is.

We will see how this all pans out, I can see this going spectacularly wrong😂

I'm really not looking forward to the plastic bits of this build.

Cheers

Mark

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When I got the Ferrari Red paint mixed for mine to match the HK film they said that going any brighter or lighter was not possible because it would just start to turn pink.

The problems I had with it refusing to dry were down to incompatibility with the Halfords white primer. Clear doping over the primer would have solved this.

Hope yours turns out better.

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Hi Gents,

Thanks for your comments. Yes Nigel, the spar is relieved to allow the retract to fit. If you have a look at the build photos on the TND website **LINK** on page 25 you will see similar. I was a bit wary about this too, but that spar is box section all along and i built mine with light ply front and back for the first 3 bays. Without relief, the retracts would not fit as per the plan.

With the sheeting on top and bottom, the wing is pretty solid.

Cheers

Mark

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Mark thanks for clarifying - that's certainly a tight fit around the retract area. I have seen photos of warbird wings have spar doublers used to move spars out of the way of wheel wells so not a new problem at all!

Did you consider relieving the flange on the retract body?

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