Topic: Wot 4 Classic build

As a slight diversion from building my Extra and wanting a model to return to flying after a considerable lay off, I have decide to build one of these.....



This is the classic version with the parallel wing and has the GRP option pack. The first thing I did was to trace round all the parts.....



........couple of reasons for this; its always worth having a record of this should you need to repair the model and I plan, at some stage, to build a larger version of the Wot 4. I know Ripmax do an ARTF Wot 4 XL but I would rather saw my foot off with a blunt hack saw than buy an ARTF. So, until Mr Foss gets his finger out and kits the XL, I intend to build my own, especially as the cowling and undercarriage are available as spares.

Anyway, on to the normal size Wot.......first part of the build is to make up the fuselage sides....



More later.....

Nice one. Perhaps it'll gee me up to stick the tail end back on my 1983 mk2.....

More Wot action tonight........firstly, fuselage sides trimmed and tided up.



Next stage is to install the firewall. Because of the wide range of engines this model will take, (30 2 stroke up to 90 4 stroke) the position of the firewall can be varied depending on the length from the back of the mount to the propeller thrust ring. You measure this then use a table on the plan to determine how far back the firewall sits. This is the engine I will be using in the Wot...



....an OS 55 AX, which has a measurement of 4 inches which translates to an offset of 1/4 inch. With this determined the firewall and the other front formers were fitted..



Finally for tonight the other fuselage side was glued in place....



More soon...

but I would rather saw my foot off with a blunt hack saw than buy an ARTF. So, until Mr Foss gets his finger out and kits the XL, I intend to build my own, especially as the cowling and undercarriage are available as spares.

I bought an XL earlier in the summer, and the first thing I did wast to strip it back to bare wood, re-glue the dodgy bits of construction - there was a handful on the fus, but the wing was riddled with bad joints. I also took the time to add a little strengthening at strategic points - a failing of many ARTFs, IMO. I re-covered it in Solartex, sprayed it black and - hey presto - a halfway decent model.

Apropos Mr Foss - I sometimes wonder if I knows or cares what is done in his hitherto good name by Uncle Ripmax and his merry band of oriental. 

Enjoy the vanilla Wot 4 - happy memories in the 1980s of my first Wot, with a Merco 61 and tuned pipe 

Enjoy the vanilla Wot 4 - happy memories in the 1980s of my first Wot, with a Merco 61 and tuned pipe 

I have a picture in my workshop of me walking back to the pits holding my first Wot 4 taken circa 1995 at RAF St Athan. I loved that model.....I still have the wing in the loft.

Ditto your thoughts on Mr Foss.....

yawwwwwnnnnnnn, get back to the extra. 

Bit more done tonight.....landing gear fitted...



Next the remainder of the internal formers were added with the rear fuselage taped together..



Finally after checking the fus for squareness, the rear was glued and the lower cross grain sheeting added..



More soon...

yawwwwwnnnnnnn, get back to the extra. 

I'm not keeping you up then....

Next bits involve 10 minutes of work then 8 hours glue drying time, so I'll be back on the Extra.........I like to keep the punters happy

Two builds going at once Brookes? Well done that man. Doesn't compare with the Extra, but even the Wot build provides an element of satisfaction. All those pins and glue too. Marvellous!      Will doubtless inspire some artf'ers to attempt a build and gain true satisfaction from the hobby.........

P.S. There are quite a few unofficial mods around for the Acrowot, but has anyone heard of any for the Wot 4 series?

Really good to see a build thread of a Wot 4 - everybody assumes everyone else knows how to put one together blindfolded!

A good point Wiz. The Acrowot, along with the Wot 4 series are pretty much modern day classics in British aeromodelling. The same could be said of the DB Sport & Scale series of kits, but these models offer perhaps a bit more involvment with the build.

Well if brookes is building an acrowot blindfolded, he's picked the wrong kit up.....  
Brian, the only mod I've done is two servos in the wings which I believe has been made standard, uprating the u/c plate to 6mm birch ply with triangular hardwood gussets whereever possible and then glass tape and epoxy over that.
Also 1/32 ply biscuits between the tailplane and the tips .

Hi Drone

Not quite sure what you meant by 1/32nd ply between the tailplane and tips?

I know the hardwood spar inset into the tailpane at mid chord was a mod introduced some time ago, and indeed the artf version has it as well. I was wondering if there had been as many mods for the Wot 4 as there seems to be for the Acrowot. Chris Foss incorporated many of the Acrowot mods into the Extrawot when it hit the market.

Where the tips are glued on end grain to fore and aft grain, quick cut with a dremel grinding disc in the right places on each piece of wood and a 1p sized piece of 1/32 ply either side adds immensely to the strength of the joint as I had a penchant for knocking them off on dried sheep's poo.
BTW the grinding disc makes the right size slot, the little saws need two and then they are slightly oversize.
I've never used the hardwood spar in thetail and I've got about 5 undamaged tailplanes and vertical stab laying round in the garage, whereas the rest of the planes are matchwood.

You sometimes knock the tailplane tips off?

How extraordinary. Never done that with any model. Ever.

The hardwood spar in the tailplane is now a Foss recommended mod. I believe it came about as a result of people fitting ever larger engines to the original Wot 4 after several tailplane failures back in the mid/late 70's. It is now mentioned in most Wot kit instruction manuals as an option.

You sometimes knock the tailplane tips off?

How extraordinary. Never done that with any model. Ever.

ive never done that either from flying, but took one off when smacked it when putting it in the car. that wold of even broken the biscuit mod too

It's probably safe to assume our models sustain more damage during storage and transit than from actually being flown......

I once foolishly engaged a fellow flyer in conversation while closing the tailgate of my car some years ago. When I heard the crunch I discovered about 12 inches of wing still poking out......

I was so annoyed with myself I built, covered and painted a new wing in 3 days flat.

Interesting discussions......

On the subject of ARTFs, I had an interesting but quite depressing chat with the chaps at the Leeds Model Shop (or Model Shop Leeds, to give their correct title) on Saturday while buying the bits I need to finish the model. This will push the price of the build over £110 (and I got the kit cheap off e-bay!!) while they could sell me an ARTF version for £86!! I commented that it only really makes economic sense to build, larger petrol powered models, using plans and kits from the likes of Belair. They informed me that Spectrum are introducing a range of ARTF large petrol models that come complete with engine and radio gear. All you do is bind the receiver to your transmitter and off you go!! What's next, they'll even supply someone to fly it for you?? 

Anyway, rant over......I managed a bit more this weekend (sorry Dom, no time on the Extra, Christmas decorations duty)

The tail feathers were assembled...



Next the servo boxes in the wings were lined...not mentioned in the instructions this, but I've always done it....and the LE & TE were attached..



More soon...

Hi Brookes

It's true the artf market has brought modelling within reach more than ever. However, there simply isn't anything to compare with that inner feeling of satisfaction when you've built the model you're flying. You know how it is. You do a nice low pass, and as the model goes by you think to yourself "I built that".

Can't beat it........ that feeling just isn't there with an artf. You don't have the same involvement.

P.S. I see you're not bothering with the hardwood tailplane spar mod? I think the range of artf petrol models Spektrum will be selling are sourced from Hangar 9.

P.S. I see you're not bothering with the hardwood tailplane spar mod?

I've built several of these in the past and never bothered. Where does it go, in the middle or at the TE?

brookes745, You mention that the self build will work out more than ARTF. Going by the ARTF kit i bought you did the right thing building,mine was terrible.From the initial look it was ok but out the box the covering was really bubbled,heat would not seat it and the wood used in fuse snapped to fit not cut,this is the triangular stock.I stripped the model with intentions to rectify but in the end i literally smashed it up and binned it.I will eventually go the way you have and build one.At the moment i am doing basic builds for practice.
If i was not new to the hobby i would of taken the kit back but being a newb i did not want to draw attention to moaning at the shop

Hi all,

I have had many Wot 4 over the years (15) my last one is still in my fleet although this has been leccyfied. It has 2 fuselages as one of my previous kits got its wing too damaged to use again, this is quite usefull as while the lipo is charging in one I fly the other using an ASP 52s. I also have the Wot 4 XL (ARTF) with no issues as yet even though I am using a CRRC 26 petrol, the other petrol is a Wot 6 (150% Wot 4) which is powered by an SPE 43. None of my Wots have had the additional spruce spar and none except the Wot 6 have had a tailplane failure and this may have been caused by flutter.

I will add that the Xtra Wot had issues with tailplane failures and it was recommended to put a Stiffener into its tailplane, either 2x3mm carbon rods or spruce.

said wot6 on finals with tailplane failure approx 20 seconds before hand

Hi Brookes

The tailplane hardwood spar mod usually entails building in the 1/4 inch square spar at about mid chord. And as far as I can see it it is about 8 inches long on the artf version.

said wot6 on finals with tailplane failure approx 20 seconds before hand

Wow......and you got it down in one piece?     

More progress tonight..... front end sheeting added and shaped. It is my intention to convert the model to elastic band wing retention. No real reason, just a personal preference...



Next the slot for the tailplane added and the tailplane trial fitted. Also the slot for the elevator control rod and exit for the rudder closed loop system cut..



Finally tonight the wing LE & TE were shaped, the wing tip caps added and the wings joined using epoxy...



Back soon....

Wow......and you got it down in one piece?     

as i realised there was an issue i was inverted heading away, and very quickly prepared myself for a walk to the crash site. as i had an element of control i tried (and succeeded) to bring the crash site closer, and managed to get it on the strip only breaking the prop (and the tail obviously) due to a hot landing speed and full down as soon as it was on the deck! i cant remember the exact damage to the tail but im sure my dad (capt2724) who's plane it is will enlighten

The tailplane had broken internally roughly down the middle and it was only the covering keeping it to the fuselage. Very lucky I had a good pilot on the tx at the time although had I had control would certainly have done the same after all one of us taught the other very well 

Are the wing tips on your Mk II solid balsa block?  On my Wots of the 1980s I always used to sand them to Hoerner wing tip profiles. They not only looked good but I think they also improved low-speed handling a little. Or possibly not.  Anyway, it's an indulgence I have carried over to this century's builds and did the same on my recent tapered wing Wot 4.

The wing tips are made up from a frame work of lite ply. I'm sure when I built my original, early 90's version it had straight tips with a plastic frame work, but I could be thinking of another model.

The wing tips are made up from a frame work of lite ply. I'm sure when I built my original, early 90's version it had straight tips with a plastic frame work, but I could be thinking of another model.

The wing tips were originally a plastic triangular shaped moulding with a balsa fore and aft former and I'm pretty sure there was some soft balsa filler at the leading edge to bolster the very thin l/e. When I bought my nth wot 4 the quality had dipped and some of the die cutting looked like it had been marked out with a bolster chisel, compared to the early ones (Mk 2 with the big V joint in the fus sides) I was most disappointed but it flew well. I think he may have contracted out to B** B***** . Just my view.

Well my ambition of returning to flying took a step closer last night when I enrolled as a new member with PANDAS (Pontefract model flying club) and I am now the proud owner of a membership card with a red "L" on it!! Although I was a reasonably competent flyer I never got round to getting certified, so its back to rookie status until I get my wings....

So back to the Wot......applied the wing bandage and shaped and joined the elevators....



More soon.....

When I bought my nth wot 4 the quality had dipped and some of the die cutting looked like it had been marked out with a bolster chisel.

The die cutting of the ply parts was pretty good; they came out of the sheet easily and only required minor fettling. The lite ply parts shapes had been milled out and were held in place by bits that were not milled, if that makes sense. I just cut them out and tidied them up....no problem.

I subsequently bought an acrowot kit and that had the milled out wood, the edges on his die cutting equipment must have given up the ghost and forced him to buy in some new method.
I'm not critical ( ), well not too much as the amount of fun I've had with his designs makes up for the one carp kit.
Good luck with your  "L" plates btw.

  I built a Wottie at least 20 years ago. Coming back after a long time away from flying, I now fly electric and am currently campaigning a Take-Away Wottie (Ripmax artf - I must have have been lucky, well put together and none of the  manufacturing problems some folks have had) which flies very well on 750-950 watts, depending what's stuck on the front.
  I was wondering what to get next, and having followed this thread I'm going to have to build a proper one, I'd forgotten how easy it was last time - I've already popped a note up the chimbley for Father C' - 17 days and counting !

Bit more done....wing bandage area sanded and covered in masking tape. This gives a nice smooth finish and gives the film covering something to key to...



Next the wing tips were fitted and sanded....



Thats the wing almost finished, just the ailerons to fit....back soon..

im not really understanding the use of masking tape 

im not really understanding the use of masking tape 

Its a technique I learnt years ago that someone thought up because they were having problems getting solarfilm to stick to the glassed area around the bandage. I had similar difficulties so tried it, it works a treat and I have used it ever since. A nice side effect is that it helps smooth over the area where the bandage finishes rather than having to sand the area hard and risk thinning the veneer.

Try it, it works, trust me...........

Been using masking tape on wing joining bandages for 25+ years here.......  as Brookes says, it works a treat. However, on the rare occasions I now join a foam wing I go a slightly different route. Having seen several foam wings (sometimes including those on my own models!) self destruct, I now adopt what I feel is a stronger joining technique. I use a larger piece of joining tape in the shape of a diamond, then lay it on both sides of the wing as in the sketch below. I feel this moves the stresses along the wing rather than concentrating them in the root area. I don't use smelly fibreglass resin anymore, preferring instead to use Aliphatic resin of the type you'd build the model with. Brushed on it sets rock hard and dries fairly quickly. It's cheap, there's no smell, and everything is cleaned up with water. Again masking tape can be applied prior to covering, although a further coat of Aliphatic also leaves a very smooth finish which Solarfilm or Tex will adhere to very well.......

Sketch here..........

Interesting technique. I've only ever had one wing fold on me, oddly enough a Wot 4, but I was being silly at the time. Never thought about using aliphatic resin like that......I'll give it a go next time......

Hi Brookes

I've never been a foam wing fan, and I've always felt the disadvantages outweigh the advantages. Once a foam wing is covered, cracks and fractures in the veneer can appear at the root area where the bandage ends, particularly if the bandage doesn't extend beyond the fuselage sides. Even then it can still happen. This is one of the reasons I chose to adopt the method I use(d). I've seen others extend the diamond shape way down the wing, sometimes approaching mid-span. Of course you can apply multiple layers too, and the best way to do this is to put the smaller diamonds on first, then the larger bits overlap the edges of the smaller ones. Looks neater.

I have an Acrowot kit here, and I may yet ditch the foam wing in favour of a built up job. I'm sure I'll probably save a few ounces if I do.