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Wot 4 revisited for the second time.

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Braddock, VC03/07/2017 13:53:40
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Some of you may remember I was banging on about a wottie that I fitted with an irvine 36.

Regrettably I became disorientated at a fair old range and it took to the trees.

Initially I thought the damage was limited to the tailplane which split and the two halves parted company. The c/f u/c and prop took a hit as well.

Finally got round to repairs and discovered that the engine mount had cracked in the legs, the reinforcing all around the wing opening had delaminated and the classic wing had taken a hit on the l/e about a foot in from the tip.

I sawed off the mount at crack and the engine, now changed to an irvine 39 I acquired, managed to fit the mount, I had to make a spacer from birch ply 12 mm thick to move the engine out. I gorilla glued doublers round the wing bay and made a new tailplane and fitted it with reinforcement to the 1/4 x 1/8 fuselage longerons that had to be cut to get access.

I finally reassembled it and popped it on the scales (it used to be 3 pounds 15 ounces dry) and to my horror I found it had gained nearly 10 ounces.

Most of this weight comes from the mk3 wing which is nearly 7 ounces heavier than the classic wing and I needed some nose weight and the u/c is now a delaminated chris foss one, taped up and that's a few ounces heavier too.

Needless to say the classic wing is now being fettled.

Braddock, VC03/07/2017 14:07:24
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wot 4 4.jpgwot 4 3.jpgwot 4 1.jpg

Few Pix to give a flavour. Just have to tidy up the covering now and fettle the other wing.

Braddock, VC03/07/2017 14:09:10
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FWIW there are three different shades of red there, profilm, solarfilm and HKfilm.

Stumps03/07/2017 15:31:59
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Thumbs up on the repairs and it should fly like a treat. Mine came home many time looking a lot worse than thatwink

Braddock, VC03/07/2017 17:18:08
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Cheers, mate, thought I hadn't read your obituary. IIRC it started out looking worse devil

Braddock, VC03/07/2017 17:33:16
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Now back to the weight saving. I weighed up all my U/Cs and the delaminated one. complete with wheels was a 7.5 ounces, The wire u/c of a 1983 mk2 wottie weighed in at 2.6 ounces and the wheels, foam ones, another 1.8 ounces so I've saved 3 ounces already. Next up will be the spinner, I'll replace that with an irvine one and should save an ounce or so.

I'll wait then until the classic wing is repaired but even now I'm well on the way to achieving 4 pounds AUW.

Hopefully, it'll be flying tomorrow and I'll see if I need to do anything else.

FWIW the c of g is now exactly 3.5" back from the LE so it's right at the back end of the recommended position.

Braddock, VC04/07/2017 16:10:49
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Half a dozen flights, irvine 39 absolutely flawless, with a graupner grey 10x6 it goes vertical til it's a dot in the sky.

I'd forgotten how confidence inspiring the wottie is.

Job's a good un.

Braddock, VC12/09/2017 18:16:44
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Wottie is now my go to plane, we've been having some windy weather down here in darkest Kent and the old wottie handles it well.

Changed the prop to an apc 10x5 and the difference is amazing.

Still can't get over how little fuel it uses, this afternoon 4 flights, added 34 minutes to the model timer and it used about 8 ounces of fuel.

With the wind straight down the strip I could plant it at about 100 feet above the threshold throttle back and feed in up and it gradually sinks to touch down about 30 feet up the strip, real confidence inspiring stuff. For my part an extra click or two of throttle when the wings start wobbling.....yes

Stevo12/09/2017 18:42:33
2699 forum posts
419 photos

Last time I flew a Wottie, I needed Time Team to dig the engine out of the ground frown

David Davis12/09/2017 19:07:52
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3473 forum posts
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Flew my Mark 3 WOT 4 on Sunday. It's powered by a Thunder Tiger 54 fourstroke. I've just weighed it at 2.3 kgs or just over 5 lbs. No wonder it's easier to fly in a bit of a blow!

I have a £20 eBay Classic WOT 4 to restore over the winter. I'll be interested to see how that compares. To me the Mark 3 wing looks like a cut-down Acrowot wing.

What does anybody else think?

ken anderson.12/09/2017 19:19:51
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Posted by Stevo on 12/09/2017 18:42:33:

Last time I flew a Wottie, I needed Time Team to dig the engine out of the ground frown

teeth 2​ did they get it out?

ken Anderson...ne...1 wot dept.

Braddock, VC12/09/2017 19:30:18
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1634 forum posts
82 photos

5 lbs is a good aim for weight, By dint of special selection I managed to get mine down to a couple of ounces under 4 lb with a small LiFe battery, wire u/c with foam wheels, irvine 39 and a 6 ounce tank. No spinner or cowl and cf ele pushrod. Its previous engine was an irvine 72 Q when it weighed 5 lbs plus including 40 grammes of tail weight.

I have to say, in its current iteration, the vertical performance is about the same but the landing speed is sloooow.

The first repair it needed added about 3 ounces.......

Stevo one of my clubmates flew after me and managed to stuff his wottie, shame really as it was a very nice one.

David I have a feeling that you're not wrong in your view, I think the airfoil isn't the same though.

Old Geezer12/09/2017 19:48:06
640 forum posts

With my third Wottie ( latest artf ) I went back to i/c - and immediately was reminded why I had gone over to the dark side. The noise for a start, the goo, the noise again, then the goo - again - and then, the final straw - the dead sticks. When I get time the big old Axi ( from my last Wottie ) goes onto the front of this one with an ESC wired onto the mount and a big old 4S in the tank bay - until then he stays in the shed. And yes, he - Wotties are male - or to be grammatically speaking, masculine. A lot of planes are referred to by their owners as she, but Wotties have to be a he!

Old Geezer12/09/2017 19:49:28
640 forum posts

I can feel a new thread coming on - the gender of a plane?

Braddock, VC12/09/2017 21:33:53
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1634 forum posts
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I can't.

Tim Flyer12/09/2017 22:00:21
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1121 forum posts
214 photos

The latest Mk 3 kit wingspan is a bit less than the Acrowot . So a fair bit different although still has a rear taper, but section seems slightly different too. I fly a repaired Mk three version that went in second flight after my son who was flying it got hit by an FPV quad. That's another story with luckily no serious physical injury. (Obviously things have changed a lot at our club in terms of safety since). My version is Laser 80 powered "weighs a ton" but has airbrakes Chris Foss style and will fly in almost any wind and has superb vertical performance. It's my plane for windier days.wot4_top.jpg

Edited By Timothy Harris 1 on 12/09/2017 22:07:25

Braddock, VC14/09/2017 13:22:31
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1634 forum posts
82 photos

I think I'm getting obsessed with weight cutting, plane currently has hitec servos in that weigh a total of 182 gms, a battery that weighs 113 gm. I have 4 corona digitals that weigh 128gm and a battery that weighs 58gm, Total weight saving =109 gm or just under 4 ounces.

I've removed the spinner and replaced it with one of those alloy spinner nuts that are reminiscent of the old ED racer, also weighs 1.5 ounces less.

Current weight without the servo/battery change is 1.94 Kilos, with the servo/battery change will be 1.831 Kg or 4.03 lbs so I'm looking for another ounce and she'll be back below 4 lbs.

Possible painless areas for examination, I have a dual extension lead to fasten the aileron lead to, it weighs 5 gms, the rx is an Orange one with 3 way gyro that weighs 42 gms, I have a futaba fhss rx which is 18 gms so I''ll be there this time next week.

That's all the painless stuff, to lose more will require holes in the tailplane and fin/rudder plus big holes in the wing...apparently there's 4 - 6 ounces saving there. I'm not sure if I want to go that far but we'll see.

Tim Flyer18/09/2017 08:48:46
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1121 forum posts
214 photos

David, Here is my Wot4 mk3 wing next to my Acrowot the wing for comparison. img_1359.jpg

Edited By Timothy Harris 1 on 18/09/2017 08:52:25

Braddock, VC19/09/2017 18:04:14
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1634 forum posts
82 photos

All the changes I want to make are now made, as the silencer fitted (an evolution one for their 36) doesn't work very well I swapped it for a westonuk's 40 - 46 size throttle pipe that I had. I have to say it is MUCH more efficient than the evolution one and reduced the noise level from the 83 ish I measured to 80 with the same prop. I changed the prop several times this afternoon first to a 10x7 apc then a 9.5 x 6 Bolly then finally to a 10x6 apc. This was the best of all and the pipe made it really sing.

I had quite a few flights but fuel consumption was less than 10 ounces so a good day today. There was no wind but I think I prefer to fly with a bit more than that.

From the weight perspective, adding the throttle pipe has kept the weight up so it's hovering around 4 pounds dry and I think I'll leave it there before I run foul of the c of g limitations as she is already 0.5" back from the rearmost recommended position and needs some down trim to fly s & l when up the right way but no forward pressure when either inverted or whilst rolling either right or left.

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