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-   -   WOT4 from UK ...... (https://www.wattflyer.com/forums/showthread.php?t=78821)

solentlife 08-25-2017 12:44 PM

WOT4 from UK ......
This is an iconic model that has been available from mid 1980's and STILL sells well in UK .... I brought the MK2 back from my latest trip to UK and am putting her together ....



I had two of these before .... both had ST60 with tuned pipe ..... could rise vertically out of hand. Performance is just truly amazing for a high winger. This is down to the fat semi symet wing it has.

I have available two power systems that will give similar to my 1980's setup :

So I have a choice .....

ASP61 glow


4250 650kv + 4S / 5S LiPo

Interesting that weights come out similar around the 780gr for both systems ....

Thats a lot of weight up front and I am thinking to move servos to the rear of fuselage to balance out instead of the factory position below the wing. This will give direct surface connection ... no need for corrective weight to balance power system ...

Looks like I will be fitting the ASP 61 .... similar to my WOT4's of the 1980's I had ... with ST60 ...

I know this is Wattflyer ... but thought it might be interesting for some ...

I did think about the E system - but it needs extra mount boxes and battery trays etc. that all add up in weight.
The ASP is basically a bolt on and fuel tank slides into place.


Wildflyer 08-25-2017 05:45 PM

Have fun Nigel, I will not put down anyone for their choice of power.

I too have many nitroplanes from my early years in RC.

As long as a person is enjoying themselves in this hobby, I am all for it.

I love the ST60's I still have 3 of the 60 class and a few smaller ones. Some planes are designed for nitro in such a way that it is difficult to mod them for E-power.

solentlife 08-25-2017 05:57 PM

This has a battery hatch but its very short ..... so fiddly to get a decent size LiPo in ... its really the fuel tank area with a lid !!


solentlife 08-28-2017 10:02 AM

Guys at my club have been discussing with me final power solution for my WOT4 .....

4:1 in favour of E-Power !!

So WF 'rs ...... its a 4250 650kv / 4 - 5S setup back again on the cards !!

Just need to build a 32mm extension motor box to take the motor. Laser cutter in ops !!


solentlife 08-28-2017 07:38 PM

OK ....

4250 650kv .... 5S 3000 ..... 50A ESC .... 13x8 prop with alloy spinner

4 standard servos

The elevator and rudder servos will be fitted to rear of fuselage to shorten control rod span and give direct control.

No added ballast as the servos in rear compensate for the bigger motor up front.

AUW ready to fly with the 5S in .... 2.22kg ...... which is less than I expected ....

Photos later once all completed.


solentlife 08-28-2017 07:52 PM

I also amended the tailwheel set-up to Chris Foss original where he used a rubber band as shock absorber link ... just means bend the stock wire close to the plastic mount horizontal to bottom of rudder ... bend a hook and cut of excess. Then embed a U wire into rudder to take the band ...


solentlife 08-30-2017 10:40 AM

Wife did the honours !


General view :


Modification to balance bigger motor / battery pack by moving servos to rear and direct link :


Chris's original tailwheel steering idea from the 80's ... instead of the wire rod into the rudder hinge line. This allows shock absorbing and reduces risk of rudder failure :


CoG spot on


Turnigy Propdrive 4250 650kv, 50A ESC, 13x8E prop
LiPo is set up for single 5S 3000mAh ... but its a very tight squeeze to get it in ... so I picked a compromise prop in the 13x8 that allows me to parallel twin 4S 1600 packs.

Just waiting for weather now !!


solentlife 08-30-2017 10:46 AM

Note I have extended servo arms so later once trimmed / sorted - I can dial her up for extreme antics.


solentlife 08-30-2017 02:20 PM

Thrust tests :

On the 5S - ESC is about on its limits .... so may swap out for larger.

52A WOT and 900W

But static thrust is a whopping great 3.5kg .... for a 2.2kg AUW ...

Next is the twin 4S ...

38A WOT and 530W

Static thrust 2.35kg .... so still enough to be interesting !!


solentlife 08-30-2017 06:20 PM

just gave it a 5 min flight .... evening and wind died just enough to get her across the road for a quickie ...

PERFECT !! 5S and 4250 dragged her up there and she flew a dream !

Flew a full 5mins as calculated .... LiPo came down at 42% ..... so that gives me between 6 and 7 mins with a lot of low throttle work ... 5 mins with spirited.

Stupid me - I fired up my headcam - but forgot to start it recording !

Only niggle - Why can't any factory get cowl blocks right so screws don't pull out or blocks split ! I just have to fix the top cowl screw block ...


Panther 08-31-2017 01:44 AM

Good one Nigel. Hurry up and get that video going... :-)

solentlife 09-01-2017 07:58 PM

Here's flight with 3S packs .... I made mistake - should have been 4S ... but in the rush to power up - picked up wrong ones !!

Then on 4S as it should have been !

But the ultimate of course was with 5S .....

Am I happy ? You bet !!


Panther 09-01-2017 10:43 PM

Very nice mate.

solentlife 09-02-2017 07:39 AM

Can't wait for weather to improve again !!

I have found some slightly larger wheels to help stop the nose overs ...


solentlife 09-03-2017 05:32 PM

The servo extenders I had on Rudder and Elevator arms have now been removed, standard arms with same stroke length of horn / arms now .... Tx DR full rate increased to compensate and regain resolution.

Wheels - Sullivan Skylite 3" have been fitted to replace the smaller stock wheels, that should help with the nose overs on grass.

Just waiting for weather to improve so I can go fly her again.

I had plain forgot how good the WOT4 is ... now its making me hanker after the AcroWot - to replace my Zlin Z50 I crashed.


solentlife 09-04-2017 05:44 PM

Electric fired smoke being added now ....

Canister to each UC leg ... the trigger is powered and controlled via the Rx ...

Flick Gear switch on Tx and #1 smoke ignites ..... flick gear switch again and #2 smoke ignites .... the trigger being sequenced.

The canisters require a short length of fuse in a small ring round the detonator, a plastic card piece taped over to hold against the solid fuel till it ignites.

Hopefully once weather clears - I shall be able to test and video ...


solentlife 09-06-2017 01:38 PM

Will be at flight site this evening ........... hope to test Smoke ...

Fingers crossed weather doesn't change !


solentlife 09-07-2017 07:14 PM

What can you say ... its a WOT4 !!


solentlife 09-11-2017 06:34 PM


solentlife 10-23-2017 10:49 AM

The 5S combo pulled the motor box apart during a flight ... but luckily the damage on crashing was minimal.

I decided to replace the ply box with alloy Stand-offs fixed to the firewall which is suitable for Glow motors.
I repositioned the threaded fixings and bolted up .... she lined up perfect with just enough gap spinner to cowl.

The thrust line was slightly less down than previous so I expected a slight trim adjustment ...

As usual she took off like a scalded cat ! 5S makes her 'ballistic' ! But the trim was spot on literally ... and she tracked nicely showing the prop line was good.

Here's the video ... (I think battery ran out on my Headcam and why the video cuts short ... )


solentlife 12-04-2017 10:12 AM

This is simply a great model to fly. I am having difficulty deciding which is my best ...

Tiger Moth - just looks so good in the air ... so much character.

MIG29 - just wants to fly and with the mods can stand on its tail and walk about ..

WOT4 - an all rounder that will do just about anything except full on 3D.


solentlife 06-07-2018 09:14 AM

As some know - at recent Model Show at Airport .... the WOT4 decided to spiral in .. seems aileron servo failed ..... it was fine on ground, but once she got going - I think the airflow overcame the stripped output spline. After when checking - it worked till I put finger on arm and it slipped.

Wing was good - just a small area of LE crushed where it twisted against fronr mount bulkhead. Opened the Solarfilm and prised back to position ... squirt of water to swell it up ... CA to fix. Solarfilm back in place and you'd never know.

The fuselage though - it was a mess. The original WOT4 was slab balsa sides with full sheet ply doublers back to just behind TE of wing. Todays is the same full sheet balsa sides but with skeletal ply doubling similar to many of todays lighter models. This of course meant that even though throttle was closed, and she went into long grass ... the fuz shattered all way back through to behind TE wing bulkhead ...


I'm a stickler about collecting as much of the debris as possible. So a Jigsaw puzzle ensues ... when I get bored arguing with Oil Operators / Ship Owners - I work on my models ...

Piecing back together can be successful, little bit of shaving off with knife ... prying / pushing / clamping / tacking with CA ... and we start to see results.


With this repair - I could have run up the Laser machine - but decided that I would go with the bits ... jig back ... strengthen where necessary with PU glue. Only one area did I have to add a jigging piece of ply to align one side of rear wing seat.

Next photos show the missing balsa sheet areas that will have the pieces tacked back in and then PU glue used to strengthen / fill the gaps. PU glue when expanded / set is lighter than the balsa and actually stronger.




PU glue dribbled into internal structure and left to work itself into gaps etc. Tape on outside to stop 'leaks' and to form.



This was the worst part - getting that tray in and keeping the wing seat as close to original as possible ... you can if look closely - see the short piece of bridging ply joining rear wing seat ..


Here are the last bits to go back ... with careful knife work ... CA and PU ... I should get a reasonable solution. I don't expect her to look perfect ... but at least be back in the air performing as any WOT4 should !


Last comment ... I am still amazed that the prop never broke ... cowl, spinner, firewall, motor, stand-offs, all still in good order ... all indicates she went in 'soft' ... but the carnage to fuselage ?


solentlife 06-07-2018 07:53 PM

Never throw away those scrap balsa bits ...


They can provide slivers and pieces to CA gaps and holes with ...




It may not be as pretty as she was - but she's strong and all together ... just needs gear back in ..




Wing seat lines up perfect ...


Later I will be removing the Film cover on her to fully sand everything back and do my own colour scheme ... but for now I need to get her back in the air to prove more work is worth it !


Panther 06-07-2018 10:02 PM

Damn! Disappointing when something that is beyond your control happens. Pity it happened in front of a crowd too.
However it looks like you have the right attitude and it is nearly fixed already.
I have seem vids on youtube where people just burn the plane at the field if that happens. Obviously they have more money than sense or just plain don't know how to fix them.

dahawk 06-07-2018 10:21 PM

Great to see the Master as work repairing. Many would have binned. If I brought home that plane in hopes of fixing, my wife would ask: WOT 4?:D:D:D

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