WOT 4. Which is the better model?

[David Davis]

There are two WOT 4s currently available as builders' kits. The Classic has rectangualr wingform, the Mark 3 a tapered wing. I believe the Mark 3's wing is cut down from an Acrowot wing but I'm not sure. I have owned both but not at the same time, besides, the Classic was powered by an Irvine 46 and the Mark 3 by a Thunder Tiger  54FS. I lost the Classic when the throttle jammed wide open and I lost orientation before the fuel ran out! The Mark 3 I gave away to reduce the size of my "squadron."

 

Which do you think is the better aircraft and why?

 

Pictures of my two below.

[Don Fry]

I’ve had all of them over the years. All 2 stroke, 46/53 size, might have a half pipe.

I would say the mk 1 is a crude basic flier. It fine for what it is, small hack, forgiving, but it does nothing realy well.

And the mk 2 and mk 3 develop to doing manouvers just a bit better. I assume as Mr Fosse developed his taste in small hacks, ( he who knows what he is doing).

Also Mr Foss is good at marketing, and will notice changes to fashions.

Whatever, they are all nice, tough, reliable, forgiving hacks.

[J D 8]

         While I would agree the " WOT'S" are pretty much all good flyers, tough the WOT 4 is not, at least not the ARTF version [ not seen inside a kit version] While the wing I recon is good the fuselage structure is of poor design.

  Starting at the front firewall is on the thin side, F1 bulkhead is weak and is open centred allowing fuel tank to protrude into the radio bay under the wing. Nice thick UC ply plate but too small to spread the load tends to rip out.

  There is little stiffening in the first part of the wing bay but the servo tray in the next section makes for much strength at the rear wing bay. Finally the horizontal tail mounted in the middle of the side panels is weak compared with a top or bottom fuzz mount.

      These are just my observations of a badly repaired Wot 4 I am fixing up that has much in common with a banana.😀

[Peter Jenkins]

Depends on whether you wish to build a model that crashes a lot or one that you fly a lot.

 

I bought a Wot 4 ARTF in 2010 following the sad demise of my wonderful 50 size Oxalys - the scaled down version of CPLR's 2 mtr Oxalys.  I made the error of fiddling around trying to get the perfect downline off a stall turn and ran out of air!   In comparison, the Wot 4 was a cart horse but I was keen to press on with my B.  I had an Irvine 53 in it and it gave an excellent performance for my B.  I subsequently flew in my first aerobatic competition using the Wot 4.  Came 7t out of 10th against SebArt Angels and Wind 50s.  I subsequently fitted a short throttle pipe (came with another Irvine 53 that I bought) and fitted that.  It needed an 11x9 APC to keep the revs down to 10,500 but gave the Wot 4 amazing vertical performance - it is almost unlimited.  This has allowed very large loops to be flown at as near a constant speed as a sport model can deliver.  Pleased to say the Wot 4 lives on and I use it to show how the B certificate manoeuvres should be flown.  It even stars on the cover photo of my book!

 

As I write, the damage done to it includes:  u/c plate removed in an off site landing following an engine cut; rebuilt wing tip following a cross wind landing that went wrong.  I have put in a mix that allows rudder to be used without the aircraft banking i.e. opposite aileron is triggered with rudder application sufficient to prevent the secondary effect of the Wot 4 rudder that is completely above the fuselage datum line.  A slow roll becomes much easier to perform like this.  Also KE is much easier since you do not need to apply opposite aileron yourself.  The mix also includes a Rudder / Elevator mix to enable KE without the need for the use of the elevator.

 

I've never flown a kit built Wot 4 but I would have thought that the difference between them is fairly small and most of the unfavourable Wot 4 tendencies can be countered with some careful mixing.  I've also adjusted the engine thrust line so that the aircraft flies straight on a full power upline and does not pitch up or down as power is increased and decreased.  As the speed changes then the aircraft will either climb or dive but does so a short while after the throttle position is changed.

 

So, in answer to your question David, it depends how well you trim the Wot 4 as it becomes a very much nicer aircraft to fly if you follow what I did to mine.  Indeed, when a fried who had an identical Wot 4 tried mine, he was amazed at how much nicer my aircraft was to fly compared with his.  So, we trimmed his like mine and he got the same sweet handling.  Sadly he then stuffed his Wottie in but it was pilot error not aeroplane characteristics that caused that problem!

 

I've adjusted the CG so inverted flight can be achieved with a small amount of down elevator.  That required the CG moving aft from the given plan position.

 

All of these changes can be made to any aircraft, of course, but they do make the aircraft so trimmed to be much more pleasurable to fly.  

 

Finally, keeping a low rate for flying the 2 rolls required for the B cert allowed full aileron to be applied leaving only the elevator manipulation to be dealt with as the roll rate remained constant.  With the Rud/Ail mix I spoke about, you can also use the rudder in the roll without causing the usual Wot 4 mayhem that would otherwise ensue.

 

The very thick symmetrical wing on my ARTF Wot 4 is very forgiving and allows the aircraft to be slowed up with confidence on the approach and landing.  Wot 4's will land without bouncing all over the place if you hold off till the aircraft is at stalling speed before landing.  However, taxying is a bit like trying to push a tea trolley with out of control casters!

Edited November 12, 2022 by Peter Jenkins
Photo added.

[David Davis 2]

Thank you gentlemen.

 

I was rather hoping that I would get responses from people who had flown both the Classic and Mark 3 ARTB (Almost Ready To Build!) and a description of the flying characteristics of each and which they prefer. As for the ARTF WOT 4, which has the Classic's rectangular wing planform, I have flown the ARTF and preferred it to my Mark 3 probably because having a built-up wing it was lighter than foam wing of the Mark 3.

 

Having said that I was a very inexperienced pilot when I flew my first WOT 4, the yellow one pictured above. At the time I found it a bit of a handful. I was more competent when I put the Mark 3 into the air and quite experienced when I flew someone else's ARTF WOT 4.

 

Last year I gave away two WOT 4s, a Classic which I'd bought as a basket case off eBay for £20 and the multi-coloured Mark 3 pictured above. The Mark 3 was restored by a lad who works as a panel beater for the local VW agent and what a fine job he's made of it! He doesn't fly as often as he used to because he became a father for the first time last year but next time he's at the field with the model I'll be sure to photograph it.

 

As for the basket case Classic, it was restored by arguably the best builder in the club and being TT he builds very quickly! He covered it in brown paper then painted it in orange water-based paint, then he gave it back to me! I've got three Irvines, two of which probably could do with a new set of bearings and a much-loved Enya 50 which doesn't, all of them currently unemployed, so you never know. 😄

 

PS. I am the same David Davis as the OP, it's just that I am David Davis 2 if i use my laptop! Don't know why!

[Don Fry]

I have done a Mk 3, pirated from outlines, of a kit I bought. Built up foam/carbon wing, foam/carbon fuselage. Lightweight HV radio.  It was very light against the kit.

It did fly better, esp vertical performance, but it was still a Wot 4. With its flaperons down, it would be a walkover on spot landing competitions.

Never flown the ARTF. Too tight to pay out that money on that.

[Peter Jenkins]

19 minutes ago, Don Fry said:

Never flown the ARTF. Too tight to pay out that money on that.

It depends on whether you include all of the bits needed to build and complete a model.  If you have the wood, the hardware and the covering materials then it's zero cost just your own labour.  If you have to buy everything then, in my experience, the ARTF wins hands down.  Only drawback is the build quality (although depends how good your own building skills are) and, possibly, the opportunity to strengthen particular areas.

[Engine Doctor]

The Mk 3 for me every time as its more agile. All the kit Wots are good strong fliers form basic to hooligan power and are tough and durable.

I wouldn't waste my money on the ARTF models although the bigger ARTF versions  do seem a bit better and stronger  . Even then a lot of the supplied hardware is rubbish and needs replacing.

Everyone has their own opinion of the Wot 4's.  I've met flyers who hate them to those that seem to fly nothing else. Personally I  think they make a good easy to build predictable flyer /hack , build quickly and easily and take all the rough and tumbles that flying from a grass field throws at them; although sometimes the U/C needs a little beefing up especially if flying from a rough or unkempt site.

Edited November 13, 2022 by Engine Doctor

[Don Fry]

Peter, depron costs basically nowt. A bit of carbon flat, to make a truss is a couple of quid, and cover in doculam. I bought 200 meters for 15 quid. I reckon I might get wrapped in it when I shuffle off this mortal coil. Some wood, sheet only, I have saws to cut strip. I don’t think the Basic costs of the airframe exceed £30. And anyone wanting a Wot 4 has a set of wheels.

I don’t think I am going anywhere near the thick end of £200. Believe me I know tight. I have a wife addicted to jewels. 
And the radio can normally be recovered from the debris field. 
 

ps, I fit weakened nylon bolts to secure the undercarriage, good enough to land roughly, will sheer before the undercarriage plate rips out.

Edited November 13, 2022 by Don Fry
More bits

[Peter Jenkins]

Well Don, you've just conformed what I said.  If you have the material to hand it costs nowt.  If you don't then my case stands.

[David Davis]

45 minutes ago, Peter Jenkins said:

Well Don, you've just conformed what I said.  If you have the material to hand it costs nowt.  If you don't then my case stands.

 

Peter, I am recording the cost of building a DB Sport & Scale Skyrider as if I were an aeromodeller returning to the fold. Build blog here: https://forums.modelflying.co.uk/index.php?/topic/50509-the-cost-of-building-recording-the-financial-cost-of-building-a-db-sport-scale-skyrider-a-surprise-for-miss-blue-eyes/page/3/&tab=comments#comment-934543

 

I still need to fit the hinges, clevises, pushrods, servos and horns but the total amount should be about £160 which is £30 less than a WOT 4 ARTF and £100 cheaper than a Speed Air. Agreed they're not the same but you get my drift.

 

 

[Don Fry]

1 hour ago, Peter Jenkins said:

Well Don, you've just conformed what I said.  If you have the material to hand it costs nowt.  If you don't then my case stands.

Peter, that comment equates to, if you want a dinner, go to a restaurant or cook yourself. Costs are the same because to have to equip a kitchen evert time. 

[Nigel R]

7 hours ago, Peter Jenkins said:

If you have the wood, the hardware and the covering materials then it's zero cost just your own labour. 

 

You still had to buy all those things to start with, so not zero cost at all...

 

I've said in other posts, most folk completely underestimate when looking at things from "ground up" point of view.

 

[J D 8]

  My WOT4 will be very low cost, the airframe was free along with all the servos, new balsa, film and other bits were given to me by an old club member when he packed up. Engine from the cupboard. [not chosen which one yet] Only thing I have purchased is a s/h 2.4 rx for £30.

[Peter Jenkins]

Sounds like a competition to find out who's been gifted stuff cheapest.  Nothing at all to do with the real relative costs of buying raw materials to make your own model aircraft and getting someone else to make one for you commercially aka ARTF.

[Graham Davies 3]

Interesting though the cost comparison is, I think the OP was asking about the relative flight performance...

[GrumpyGnome]

Having flown both kits, I can't tell the difference tbh - I'm just an average pilot so the subtleties are probably lost on me. Both flew on SC70FS - great all round sports models.

 

I prefer the look of the tapered wings.....

 

[Jason Channing]

I've built and flown both, and to me the Classic fly's better . much better slow speed and more predictable then the tapered wing, Their isn't a lot that cannot be done with the classic and if you spend time setting it up its a great plane, too me the artf is not in the same category and does not have the same wing section as the kit built planes. 

[GrumpyGnome]

Totally agree re the ARTF.....

[David Davis 2]

A couple of years ago I gave away a basket case Classic WOT 4 to my club. It was restored by one of the best builders in the club who gave it back to me! He covered it in brown paper and painted it in water-based orange paint! Maybe I should shove my beloved Enya 50 into it!

[Tom Gaskin 1]

Depends what you want it for - the Classic is an excellent sport/funfly model, the MK3 is perhaps a more 'precise' aerobatic model. They are both tough,versatile models that I have powered with piped two-stroke, four-stroke and also electric motors.

 

 

Tom

[Peter Jenkins]

As one who has flown a Wot 4 Classic/ARTF in a competition I would not use the word "precise" to describe it!  A proper aerobstic design is much easier to fly but, wigh its Irvine 53 Mk2 and throttle pipe my Wot 4 is great fun - but still hard work to fly accurately.  You only realise how much more precise a pure aerobatic model is when you fly one.  That is not to say the Wot 4 cannot be used to fly aerobatics to a good entry level standard but you do need to mix out the very powerful secondary effect of the rudder.

[John Lee]

I've had all the various standard size WOT4's since they were first produced and my preference is for the straight wing Classic. For me they are very much for wringing its neck out and I find I can take more liberties with with the Classic than with the tapered wing.

 

A number have decried the ARTF but I've found them fine and my all time favourite is the ARTF 'Pro'. These were straight winged, had a lightened structure & enlarged control surfaces. Mine is electrified and is brilliant to fly. Alas they were only produced for a very short time but if they made another batch I would certainly buy another to keep in stock for when mine eventually ends its days.

 

Edited November 26, 2022 by John Lee
Photo added

[J D 8]

  The ARTF pro is the best flyer of the lot, being of the type that is light and strong enough to fly The down side is a model that if it has a whoopsy it's a bin bag job. For an experienced flyer this is fine as the chances are low.

    However many WOT4's are a second or third model, for learning aerobatics, and getting used to a heavier faster flying type and are as far as the standard ARTF is concerned could be better structurally to withstand the inevitable learner incidents mostly on the landing. 

   

[Nigel R]

If you're capable of going from plans then I'd skip the Wot entirely and build Mike Delacole's Rival... Flies better, easier to build, stronger, simpler.