Wot 4 MK3 Classic

[Devcon1]

A nostalgia trip with a few twists.

Fuselage sides laid up, to get identical sides I've place some scrap balsa into the former slots to align both sides and then made a square sanding block to true the outside profile.

[Devcon1]

Motor mount ready to glue.

Not going to be a quick build but a nice little project to ease into Autumn.

I'll add a couple of small fillets to give lateral bracing.

[Devcon1]

To get my split rudder/airbrake I've had to widen the top sheeting by 1/4".

Fuselage clamped up.

cooling solution for the ESC.

Air scoop from a block of balsa sanded inside and out then covered with film with a little bit of FOD from a car repair P38 mesh.

[Devcon1]

Battery access will be via a top hatch and slid into a "coffin" battery holder.

Although most of my recent flying has been with foam/moulded stuff the process of from building from either plans or kits still gives me huge pleasure.

Don't you just love wood.

 

 

Edited By Devcon1 on 18/09/2018 20:46:31

Edited By Devcon1 on 18/09/2018 20:48:14

[Devcon1]

Always disliked self tappers into blocks to retain cowls so decided to drill 1mm and then tap to 2mm and retain with 2mm allen headed machine screws.

I dribbled some thin cyano into the tapped hole and ran the tap through again after it dried.

The fixings will be a good match for the mechanised battle damaged look I have planned for it.

[Biggles' Elder Brother - Moderator]

Coming along nicely Devcon!s

Really takes me back, I built my first WOT4 from a Chris Foss kit many years ago now. Lovely plane, had a Irvine 53 on board (the classic combination!). Sadly she came to a sticky end one evening in a mid-air collision - the only time that has ever happened to me (touching every bit of wood around him!)

BEB

[Devcon1]

Thanks BEB,

I think I'm happy with the battery location and mounting.

Now just in case I'm accused of of plagiarism, I had a weeks head start on BEBs build but I am seeing a theme on the builds in terms of weight, COG and layout but what I can say his conversion will be airborne far sooner than mine.

Ply used to make the battery box has been truly recycled from a defunct slope soarer fuselage.

Holes primarily for cooling rather than weight loss.

Edited By Devcon1 on 22/09/2018 14:56:33

[Devcon1]

Twist No1

To give an extra angle to the flight envelope I'll have a split rudder.

With a taped hinge I've replaced the original 1/4" component with two 1/16" versions.

For simple rudder input I'll have the appropriate half moving in isolation and when in "Flap" mode they will mirror each other.

[Biggles' Elder Brother - Moderator]

Oh - I like that! Very different. It'll be interesting to hear about that in action.

Re plagarism: well to the problems the conversion offers there is one obvious solution - we're both experienced modellers, it's kind of inevitable that we'll independently end up in the same place with minor variations.

One thing that is interesting is how on the classic build the lower fuselage curves up at the front; on the ARTF its simply a straight incline - slope but no curve. That was obviously done to simplify manufacture, but it does lose some of the grace of the profile of the original.

BEB

[Devcon1]

Radio tray brought forward a bit, now with telemetry there doesn't seem much logic to placing the cute little FrSky LiPo sensor in a visible position but in keeping with the planned techno look I'll have visible in a little window.

Two 81s to drive rudders. Must remember that the rudder neutral position will actually be full servo deflection.

[Piers Bowlan]

Neat and interesting build Devcon1. I like the machine screws tapped into the wooden blocks to retain the cowl, I might copy that, talking of plagiarism! I built a Domino flying wing for the slope centuries ago with a split rudder added. I didn't notice too much air braking effect but I did notice the huge pitch change, but then it was a 'plank' and very sensitive in pitch. Incidentally, I removed the church roof in the nose and replaced it with an Astro motor but it was pretty anaemic on the 7 nicad cells of the day. No such problem with your set up - progress!

[Gary Murphy 1]

What a really great build, wish I had that much skill. looks so neat and clean. will watch what follows. well done.

[Peter Christy]

That tip about machine screw into tapped wood is how I've retained wings for years, albeit using 5 or 6mm nylon screws! I forget who it was taught me that trick - probably Mick Wilshere! Much easier than using blind nuts, and every bit as strong!

I've also used it for retaining dural undercarriages and tailplanes - most recently on my Jackdaw.

The trick for wing / undercarriage retention is to make sure the wood is thick enough and thoroughly secured(!). Once the threads are tapped use a dribble of cyano to beef them up - just as you suggest.

I must admit, I hadn't thought of using the same trick for cowls, but I can vouch for its effectiveness in retaining wings, tails and undercarriages!

--

Pete

[Devcon1]

Thanks all.

Just show there's nothing new, I used the tap method in my Dawn Flyer for the wing bolts to save weight. I Think I'll do it for this one now as well.

I've put my old 35Mhz aerials to good use as hole cutters for the rear snake exits .

I won't fix the snakes in yet but will thread them through after covering is completed.

Finishing the bottom sheeting was a weight off my mind.

[Devcon1]

After numerous stress/load calculations and estimating the COG effect I let loose with the hole saw.

It doesn't look pretty but I'm happy with the result.

I weighed the material removed and with crude estimations 25 g came out with an estimated 45 g saved at the nose.

Final pic gives a feel of some final finish visuals.

[Nigel R]

There's a certain functional elegance about having a lot of holes!

Tapped blocks of ply or hardwood for me too. Wing in place, drill, tap, drop or six of cyano, job done. How are you going to thread the snakes through after covering? I'd like to do that on my current build.

Edited By Nigel R on 25/09/2018 22:43:01

[Devcon1]

Nigel R,

It's a fairly short run from the rear exit to the front guides so , already tried successfully, with some thin piano wire to find the holes then used it to guide the snake outer neatly through the holes. Would be harder with a longer run I guess.

On the holes I took the view that many full size airframes seem to have rather more empty space than structure.

Edited By Devcon1 on 25/09/2018 23:41:35

[Piers Bowlan]

I am surprised how neat the holes are using a hole saw on balsa, food for thought indeed! I have a couple of porky airframes which might benefit from this holy treatment!

[Biggles' Elder Brother - Moderator]

I find the trick is to use a fine-toothed hole saw (if you can find one!) on a higher speed setting. Then, as my dad was fond of saying, "let the saw do the work"!

BEB

[Devcon1]

As advised. Keep the speed up and very little pressure, almost like using the hole saw as a sander rather than a cutter.

Where one or two holes went a bit messy the cause was me allowing the drill to drop too quickly after the pilot drill went through, I learnt to work the drill horizontally and not vertically.

I noticed very little difference in torsional rigidity before and after, I've taken the view that I plan to fly it and not crash it so convincing myself I can take one or two liberties.

Those wings better watch out.

[trebor]

Watching as Ive got one to build when I get sorted out.

[IanR]

+1, per trebor.

[Devcon1]

Twist no 2

Idle hands and all that.

Whilst pondering other parts of the project I was reminded of how messy the edges of a battery hatch can get during the life of the airframe. Solution..

A self ejecting battery hatch, having a surplus of channels, FrSky Sbus for the wings, I've used a cheap servo, kitchen shelf clip, spring and alloy tube to fashion a device.

May need, or maybe not, need to lighten the spring as at the moment the hatch post is ejected rather energetically about a foot into the air.

Rather silly but it makes me smile. Would do a video but it seems a bit complicated to post one.

Edited By Devcon1 on 28/09/2018 23:19:32

[Rich too]

Nice build 👍

[Devcon1]

Back on it.

3 projects on the go in rotation. Just finished this one..... M1 A2 Abrams TUSK II

One of the rudders covered. Aiming for a mechanical look .