Now then what can
I say about the Wot 4 (Named after me:-) from Chris Foss, well… a lot to be
honest as the wot 4 must be the most popular I.C sports model kit on the market
today. Unless you know different (no doubt somebody will tell me so.)
It is rare for a model to both influence and
dominate to such a degree as the wot 4, but when the original version first
appeared it possessed those unique qualities destined to make it a classic
for years to come.
Here it is... |
The wot 4 set new standards in both kitting,
building and flying by which others were and are judged, with it's maneuverability,
slow flying characteristics and aerobatic performance it's easy to see why
it is the mainstay of a lot of club flyers to this day.
Just a small selection... |
I have now built 6 Wot 4's all just as brilliant
as each other. The one that springs to mind is one I never did finish, but
sold to a fellow club member. He went and fitted a Super Tiger 90. I did get
to fly it and shall we say it was adequately powered!! Doing knife edge loops
with no problem at all.
So what do you get in the kit?
well I'm building the standard kit and the first thing that you see on opening
the box is the instruction manual, and a British Model Flying Association
leaflet that explains a little about the different types of models and about
joining a club and operating your models safely.
The instruction manual is of 6 A4 size sheets with a introduction
and some building notes plus a note on the handling and storage of the foam
wing,
That's the front page, it then go's on to a parts list of
the kit. Now before I go on to tell you about the building there is an options
section in the instructions that covers things like fixing the wing on with
rubber bands, fitting a stearable tailwheel and fitting flaps, airbrakes or
extra wide ailerons, plus a section on how to lighten the wing and the fitting
of two servos, as the standard set-up for the ailerons is one centre mounted
servo have made some of these mods and I will point them out as I go.
Inside the box... |
All of the supplied materials in the kit were up to the usual
high standard and appear to but subject to careful selection.
I am going with the extra wide
ailerons and to do these you have to glue some ½" sq. to the standard aileron
LE, you then remove ½" from the rear edge of each wing panel and glue some
¼" x 5/8" to this new cut edge, I also glued the LE and the tip facing as
per the kit.
The tip facing is cut from part number 1a and you only use
half of it as the other is used in the fuz construction, It's interesting
to read the instruction regarding the mod to the ailerons as it say's (for
an outrageous roll rate try a 33% increase in aileron area - not for the faint
hearted!) Each panel was then sanded and put on the building board upside
down to check the fit as the panels are put together, all was OK so I then
glued them together with 5 min epoxy and left the join to dry.
Wing seen here with wells cut into the foam for seperate
servo's... |
Next Imade a servo box in each panel, this I did by measuring
out 10 inches from the pre-cut servo box in the wing root, I also cut a channel
for each of the servo leads at the same time. Each servo box was then lined
with 1/16" balsa and the channel was capped with the same, I then fitted the
trailing edge at the wing centre section and made and test fitted the ailerons,
the wing then had the fibreglass bandage added and was put to one side so
that I could then build the fuselage.
The construction of the fuselage
is very straightforward you start with the sides surprise, surprise!! Now
these have to be made up from two pieces of 1/8" sheet part 1 and 1A but first
you have to mark two lines along each side of part 1, these lines are for
use later when you have to glue the doublers on. The first line is marked
at 1.1/4" down from the top the next line is marked at 2.1.4" down from the
first, once this is done you can then glue the two pieces of sheet side together,
it's also a good idea at this stage to glue together parts 4, 12 and 13 as
these will be needed latter on in the construction.
Firewall and next former in position... |
It is a good idea to weight the rest of the fuselage
to keep it all square... |
With both sides pinned down you can now add the top and bottom
doublers plus the longerons and the vertical uprights (you have made a left
and right side haven't you?). You then have to taper the longerons at the
tail end but only on one side. The first former you have to fit is the main
engine bulkhead part 4, I marked and drilled the holes for the mount and fitted
the captive nuts to this before hand, once this is glued in place you then
fit former 5 and undercarriage plate 6.
I glued all these formers in place with 5 min epoxy as once
this is dry you can fit the other side to this assembly, the spacers are then
added behind the main bulkhead. One thing about the wot 4 bulkhead is that
once you have decided as to your engine size and type you can fit it in any
position you like so that you can fit the cowl, I never have used the cowl
on any of my wot 4s so I just fitted the bulkhead at the very front.
Going back to the construction, you now fit the main undercarriage
plate and formers 8, 9 and radio tray 10 all this I fitted as a dry run also
checking that the tail end came together right, and once I was happy with
the fit I glued everything in place with CA.
Next comes the cut out for the tail plane. After I had glued
the back end together but before I fitted the top sheet, I made the cut out
for the fin, as this top sheet is in just one piece of ¼" balsa, the bottom
of the fuz is then sheeted in 1/8" balsa with a small piece of light ply for
the stearable tail wheel.
Before fitting the 3/8" sheeting over the tank bay I fitted
former 12 and wing bolt plate 13, I then temporally fitted the wing and drilled
the wing bolt and wing dowel holes, the 3/8" sheet was then added and all
the fuz was sanded to shape.
All the tail parts are made from
¼" sheet. The tailplane is made up from 5 parts and the fin made up from 2
parts, going back to the tailplane this consists of the main center section
with tips and two triangle pieces as the leading edge.
Now the main center section. I made a cut out in it to let
in a strip of ¼" sq spruce, I then glued the leading edge parts to this and
the tips, doing this makes the spruce come out in the middle of the tailplane.
This particular mod was listed in the instructions that came with the old
MK2, it advised you to insert a piece of ¼" sq spruce in the tailplane if
you planned to use an engine in the top end of the power range.
The finished tail parts (see text)... |
As for the fin, I let the ¼" sq spruce in to the main fin
before gluing the two parts together, you can see from the photos The way
in which this was done as it is easier to do than write about. I also increased
the size of the rudder by fitting an extra 1" strip to it in fact I had to
fit this in to it because of the shape of the rudder, the elevator I have
made as per the instructions.
At this point I fitted the throttle
cable and gave all the parts a final sanding, I then fuel proofed all the
inside of the fuselage front and decided on a colour scheme, I think you have
to admit the finished model looks very nice, all the covering was solorspan,
as is all the trim.
The finished product, Top... |
...And bottom |
One little trick I have learnt over the years is to go over
all the joints in the covering and the trim with fuel proofer I also do the
same with any stickers I fit, I then fitted all the radio gear, the engine and
tank and made the elevator pushrod up and the closed loop control for the rudder,
after checking the balance and setting all the control movements it was time
to go and test fly.
The day of the test flight was
bright, with a cold blustery wind blowing, I assembled the model and did a
range check then fuelled up and started the engine I then did a range check
with the engine running and one last check of all the controls.
Out onto the strip and lined up for take off I opened the
throttle and the wot4 was away a little back pressure on the stick and it
climbed out nice and straight. I made a nice big wide circuit of the field
and still no change to the trims. As they say in all the best kit reviews
"it flew straight of the board" So it was time to check the stall. Throttle
back and slow down then apply up elevator, all that happened was the wot4
just nodded it's head.
I then tried the same with some flap and as before it just
nodded it's head. So I opened the throttle and went on to try some aerobatics,
loops can be made as large or small as you like. The model rolls well as you
would expect on high rate they are fast and with the recommended movement
they are a nice speed not to fast and not too slow. All the control movements
had been set as per the instructions on lowrates. At high rate I set them
to get as much movement as I could.
Stall turn next and with that big rudder it went over almost
instantly, knife edge?. Well again with that big rudder it sits on the knife
edge all day and if you open up to full throttle it will climb in knife edge,
inverted isno problem and I didn't have to hold a lot of down in, in fact
if I pushed too much down it started to climb.
|
Proud owner and his trusty Wot4...
'Ere is that a Bumpy green hat he's got
on. and a BG sticker on the wing?.-ED
|
I then decided to settle down and do some flick manoeuvres
and as you would expect it did them all with no fuss. Flying a model like
this is easy, that is to somebody with some aileron experience and because
of this it is plain to see why the wot4 is the cult model it has become.
I know of some people that would say there is no challenge
in flying a model like the wot4 but then who want's to make their flying difficult!
Easy flying is enjoyable!
I then went on to try square loops, Cuban eight's, outside
loops and combinations of these all no problem. One thing that I was and am
very happy with is the vertical performance, it will climb and climb and climb.
Now my engine set up is as follows: I have a Irvine 46 with a APC 11x 8 prop
a Taylor plug all running on Southern modelcraft 10% nitro caster based fuel,
and I'm very happy with this set up.
The time then came to land I did a long approach from well
down wind and just let it settle down on the edge of the patch with no worries
about coming in too slow as I new that the stall was a non event.
I think my opening statement
says it all, not wishing to repeat myself the wot4 is a world leader. It is
rare for a model to both influence and dominate to such a degree as the wot4,
the standard of kitting is good and I must say that the only thing that I
would like to see to improve the breed is a built up wing as that would then
help to make the wot4 even lighter. There was nothing in the kit that I would
or had to change and the mods I made are only for my own benefit and in no
way do they detract from what is in my mind the best sports model on the market.
I know that a lot of you out there are thinking if he has
built 6 of these then it's only natural that he will think the wot4 is the
best thing since sliced bread, but I have built a lot of other sports model
in my 28 plus years of modelling and I always come back to the wot4.
Be good.
And if you can't be good don't get caught.
Wayne.
Article by Wayne Haycock from Chase
Radio Controlled Aero Club
6th April 2002
| Comments left by others... |
| Comment by chris foss on 00000000000000. Rating none |
i will be soon bringing out a wot 5
wish me look |
| Comment by B.BAILEY on 00000000000000. Rating none |
HOW ABOUT PUTTING A SECOND BEND IN THE AILERON TORQUE ROD AT THE FACTORY AS THE 1/8" PIANO WIRE IS A BIT OF A PIG TRYING TO FORM THE RIGHT ANGLE BEND AND GETTING A TIGHT CORNER. |
Good review. I have built two in my last 20 years. My latest having lightened wings. Super flyers with Irvine 53. Have flown with ASP 61, too much and Saito 91, too heavy. |
| Comment by on 00000000000000. Rating none |
| Comment by on 00000000000000. Rating none |
irvine 40 a little under powered
irvine 53 ballistic missile
irvine 46 aaarrrrr just right 10x7
|
| Comment by on 00000000000000. Rating none |
I've got a Wot 4 with an SC91fs! It is absolutely incredible! The only mod I made was to take the servos out and put them at the back of the fuselage, like on 3D's. |
I have had 3 of these superb models in first in the early eighties. 91fs only adds weight my last one prop hanged with ease on a Saito 56 12.5 x 6 Bolly. Please mr Foss scrap the aileron torque rods and make provision for 2 servo's also get rid of those horrible plastic clevises other wise exelent value for money. Has to be the best sport model ever. |
| Comment by Russ on 20040314202130. Rating 1 |
Bought and built (pre ARTF) WOT 4 April 1984 (£43) Still flying EVERY weekend. Flown on Merco 61, OS 45 FSR, ASP 61 and now best of all on ASP 52s. Calculated at average speed of 50mph its flown the equivalent of Lincoln UK to Los Angeles USA. Anyone got one older ? |
| Comment by a on 20040319210840. Rating 5 |
superb aircraft!! i have a mk1 powered by a os 60max-h 12*6 as a tug, and a brilliant mk3 with os 46fx 11*6. both under proped but will go vertical all day!! |
| Comment by richard on 20040715205726. Rating 5 |
hi i would love to build a wot 4 or a acro wot. but ive never built before im scared that im going to mess it up how hard is it to build and whats the instructions like i did have a acro wot and loved it. but it got shot down by another person flicking his switch on and killing mine please help. |
| Comment by Conor on 20040827003412. Rating none |
I am nearly finished my build,but i screwed up the tail piece slots,ther too big and far from accurate.what to do?> hakko1872003@yahoo.co.uk
Thanks. |
| Comment by clive on 20040901230906. Rating 5 |
Advised by local club to build as a trainer, previously only a little slope soaring experience. Easy to build for a novice (get advice from club if stuck). Take off easy despite paranoia, loops first flight, cuban 8 on second flight - unreal, keep initial flights short, brain seizes up but model very strong. Absolutely fautless - everyone should have one! |
| Comment by andy f on 20040911164759. Rating 3 |
I had a classic when I first started flying, then built a Mark 3 last year. Absolutely superb chill-out flyer, or scary aerobat if that's what you want. Beautiful aircraft, easy to build, looking forward to the Wot5. |
| Comment by mike beddow on 20040926205316. Rating 4 |
had one of these about 20 years ago.Just built the latest version powered by an st46.goes like stink and is as tough as old boots.Far better than all this chinese artf junk,at least you know how its built.possibly the best sport model available. |
| Comment by Peter on 20041128204944. Rating 4 |
Instead of using one standard servo in the centre of the wing use two HS 85 MG's, one for each aileron. These fit next to each other in the same space and you can then use mixers on the computer transmitter without having to cut the wing panels to pieces. Also a much neater solution as they don't stick out in the breeze or get covered in oil. |
| Comment by Dave S on 20050630143418. Rating 5 |
Currently on my 8th (I think) built over a 20 year period. Superb model, this one has flown on an Irvine 53, an AXI electric and now an ASP 70 FS. Might be the only one in Finland, certainly surprises everyone who sees it fly!
|
| Comment by Ian Till on 20050816205046. Rating 5 |
Fabulous first model, so forgiving in flight, with an OS40LA. Mine was my first build and that was some 9 years ago, following which I didn't fly it largely because I was scared of breaking it.
Approx two months ago I joined a local club and took it up with an instructor and learned to fly on it from scratch.
Mine's a Classic (though is really a Mk3 with a classic wing). The build really was simplicity itself and everything was well thought out. The 40LA pulled it round adequately as a trainer and was easily powerful enough for loops, rolls and some pretty stall turns, but I've just upgreded to an OS 40FX, which (appears at least) to have bags more power and I can't wait to take it out for it's second maiden flight at the weekend. Control effects are really clean and precise, inverted flight is a dream.
One thing I will say is that I really rate the plastic undercarriage bolts idea - although I've broken mine twice on fairly good landings (longer grass than ideal :-) they really do their work and encourage the pilot to bring it in thoughtfully. I've seen a Wot 4 with the base of the fuselage ripped out due to metal bolts being fitted and that spoke for itself. If you break your plastic bolts too easily, consider moving up to M6 size, perhaps introducing a small filed notch to weaken them slightly.
Great kit, still (8 years on) is getting some admiring glances and lots of attention from others in the club who want to progress from their Tutor 40s and Jumper 25s.
Great plane, I think I've said enough! :-)
Ian. |
| Comment by tommytucker on 20051202200539. Rating 5 |
Just obtained mark three made by mate be trying after Santas been will be putting Super Tiger 45 in never tried one starting to shake in my boots with antisipation Tot |
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