Wot4 XL artf Build

[cymaz]

Decided not to fit the tail bracing for the moment, I will do it in the future. Though the tail is very sturdy..

Final weight was 4.5Kg - 10 lbs. I'm sure the extra weight was

1. nose weight added because of rear servo
2. tank platform on CG
3. extra bracing and glueing

I will change the U/C to a lighter one....that will save a bit as the stock one is quite heavy.

Edited By cymaz on 19/08/2016 19:48:03

[Kim Taylor]

Hi Cymaz,

Looking good - a bit blunt at the front without a cowl, but that's a fair old lump of a motor, so I guess there wouldn't be much of it left anyway!!

I don't think it's possible to get under 9lbs with these, unless you went with a very light motor at the very bottom of the recommended range. I did work it out in detail before I started mine, but from memory it weighs the same as if I'd fitted an ASP120fs and filled the supplied tank with fuel and as I said earlier, it comes in at just under 91/2 lbs.

I'll post up the details of mine along with a few images of what I've done to convert it to leccy soon. Bit tied up over the weekend picking up my new toy if it checks out ok - 1963 Triumph Tiger 100 500cc motorcyle, just like the one I had when I was 17. Only problem is the 12 hour round trip to pick it up, still no pain no gain as they say!!

Anyway, back to the WOT - all you need now is a decent day to maiden it - not looking good for a day or two, is it?

Kim

[cymaz]

Thanks for the kind word. I think if I put the cowl on there might not be much left of it.!

Next weekend will be good. According to the forecast. Need to run a tank of 20:1 through it first

[Terry Walters]

That was quick Cymaz! I'm not the best flyer but I do enjoy flying the Wottie and I fly it more than any other aeroplane in the hangar and it makes me smile too. The French guys at my club love it too and are always asking questions about it. It gets a bit humorous when I try to tell them the name of the designer Chris Foss as a 'Fosse' over here is the cess pit!!

Best of luck for next w/e with the weather - the WOT 4 should fly very well.

Terry

[cymaz]

Cheers for the support Terry.

3-4 weeks to build an artf...I thought I was dragging my feet a bit

Job for today is mix up some 20:1 to run the engine in and double check the CG.

Hopefully Kim will put his Wot4 XL on and we can have a thread for all things Wot4 XL.

Edited By cymaz on 20/08/2016 10:47:37

[Former Member]

[This posting has been removed]

[cymaz]

Posted by Percy Verance on 20/08/2016 11:09:01:

You don't build an artf cymaz, you assemble it................

So true....You also swear, bleed over, cry, moan and curse over it as well

[cymaz]

Posted by Percy Verance on 20/08/2016 11:09:01:

You don't build an artf cymaz, you assemble it................

So true....You also swear, bleed over, cry, moan and curse over it as well

P.S. I have just done the second CG using my balance machine,(sounds posh but it's a heavy base with various hole widths into which I slot some T shaped dowel).  Ever so slightly nose down at 105mm.

Also nearly forgot to do lateral balance . Fuel mixed, batteries charged......Now how about some nice weather, thought not 

 

 

Edited By cymaz on 20/08/2016 12:24:52

[Shaun Robinson 1]

Looking good 👍 Fingers crossed for good weather on Saturday as looking forward to seeing it in the air! Thanks for taking the time to do a blog it's been very interesting! Good tips for me to pick up on! Shaun

[iqon]

Posted by Shaun Robinson 1 on 21/08/2016 16:53:51:

Looking good 👍 Fingers crossed for good weather on Saturday as looking forward to seeing it in the air! Thanks for taking the time to do a blog it's been very interesting! Good tips for me to pick up on! Shaun

+1

[cymaz]

So Wots next .?

[flight1]

Posted by cymaz on 21/08/2016 17:40:57:

So Wots next .?

THIS ......go on..... she won't mind

Edited By flight1 on 21/08/2016 18:56:17

[Terry Walters]

WOTS 4T!

[bert baker]

Gammon

[David Davis]

I suppose we could all record our experiences of assembling and flying the WOT4 XL.

[Shaun Robinson 1]

Cymaz could help me build an xl?? 😜😱

[cymaz]

Posted by Shaun Robinson 1 on 21/08/2016 19:19:32:

Cymaz could help me build an xl?? 😜😱

Step by step guide here

I will keep posting my experiences. Flying hints and tips etc.....

[cymaz]

Ran the new Evo 20gx2 tonight.

A bit recultant to draw fuel for the first time. However, after a couple on mins of hand prop turning and flicking over the fuel finally came through a treat.

Followed the manual to the letter....after about 10 mins the Tx started to show low battery so gave up and went in for tea

It did hand flick start a couple of times, which is encouraging. There is still a long to the bottom of the 14 fl oz tank. I will finish the job tomorrow evening, all being well.

[Rich too]

Good stuff. As a matter of interest what tx battery are you using? I changed mine for a Lipo and it lasts for ever, it's brilliant.

[cymaz]

Posted by Rich2 on 22/08/2016 19:31:02:

Good stuff. As a matter of interest what tx battery are you using? I changed mine for a Lipo and it lasts for ever, it's brilliant.

Eneloop 6v. As it has a rear servo need some extra nose weight

[brokenenglish]

Posted by cymaz on 22/08/2016 21:07:57:

Posted by Rich2 on 22/08/2016 19:31:02:

Good stuff. As a matter of interest what tx battery are you using? I changed mine for a Lipo and it lasts for ever, it's brilliant.

Eneloop 6v. As it has a rear servo need some extra nose weight

Isn't there some misunderstanding here?

[Kim Taylor]

So, as promised, I'm back with a few details of my 'leccy WOT4XL.

I won't go into any basic build detail, as that's been covered by Cymaz - I'll limit myself to the electric install.

Firstly, I reckoned with an AUW of around 9 - 10 lbs, I'd need something in the 1300 - 1500w range to give adequate performance (for me!!). After searching high & low and finding everything out of stock, I finally found the E-Max GT4020-09, rated at 65A, 1430w 470kV. Advertised as suitable for spinning a 16x10 prop at a little under 7000rpm.

The ESC is a H-K item, rated at 70A continuous, 100A peak. I wanted the 80A, but of course, they were out of stock. If it proves to be too close in testing, I'll uprate it - more later.

The image above shows the install of the motor on standoffs, made from M4 studding with 10mm O/D aluminium tube outer, which can be persuaded to go over the nuts and gives it a nice rigid fixing.

I used the centre lines marked on to the bulkhead and assumed that any necessary side / down thrust is built in - all other build threads seem to suggest this is correct.

The ESC is mounted on a liteply plate, which is cable tied to two of the standoffs - I thought that it'd be nicely in the airflow there for cooling. Talking of which -

I added some slots in the front of the cowl to allow (hopefully) adequate cooling air in, and you can see in the picture that the cowling provides adequate exit for the cooling air along its back vertical edges.

The battery is a 6S 5800 Zippy which I'm hoping will be enough to give me 10 minutes or so duration, bearing in mind I won't be tearing the sky up - just circuits and mild aerobatics at the most. Whatever, it wouldn't be easy to fit anything bigger. The battery is situated on a tray which sits diagonally between the bulkhead below the wing leading edge and the next bulkhead forward, just behind the fitted cowl - hopefully the couple of images below will be clear.

As I hope you can see, it fits in there quite nicely. I've probably gone OTT on the velcro straps, as the battery tray itself prevents any movement at the rear.

I've also fitted an arming plug, which you can see in the last image, just as a precautionary measure.

The battery tray is made from liteply with balsa fillets and is actually very rigid.

As we can see, I've jumped a bit, as the battery hatch needed to be formed. I did this by using the time honoured 'cut first and ask questions later' method, but it actually worked out OK. Basically I cut across the fuselage in front of the wing leading edge bulkhead and the next one forward, which happened to be the base of the 'windscreen'. Then carefully feeling my way vertically down the sides of the fuselage to the thickness of the wood forming the hatch and running the knife diagonally up the 'windscreen' line, joining the two previous cuts.

The hatch itself is fixed at the front by two pegs, made of 5mm ali tube and at the rear by two magnets which will hopefully be clear in the images.

I've had the whole lot together and test run. With the lipo as received from H-K (storage charge) I got the following results using the aforementioned 16x10 prop:

Current 67.5A (Over spec I know, but I'm hoping it'll reduce in free air and one click down on the throttle reduces it below 65A)

Watts 1440.

These are from memory. I don't remember the voltage,, but doing the maths, it looks about right at around 21.5V, bearing in mind the battery hadn't been charged. I'll do a proper run in due course with a fully charged battery, which should bring the amps down a tad. The ESC, which I know is tight, didn't even get warm in the 2 mins or so of running which I did.

What else can I say - due to my meticulous planning (and complete fluke) the c of g is spot on 105mm from the leading edge. I still need to balance it side to side (to counteract the offset battery installation) which I'll do with a stick on wheel balancing weight when I can blag one from my son - needs to be about 10g.

Please bear in mind I'm by no means an expert in electric flight - I'm returning to the hobby after a 30 year break, so if you think I've done anything wrong, or could improve on anything, please don't hold back - I'd rather get it right before committing to flight.

Kim

p.s. Final edit I promise - The spinner is rubbish and will be replaced with a better one before flight.

Edited By Kim Taylor on 23/08/2016 16:13:58

Edited By Kim Taylor on 23/08/2016 16:17:45

Edited By Kim Taylor on 23/08/2016 16:27:49

[Kim Taylor]

And just to add, as my original post was too long (I always do go on a bit) that all that needs to be done is to fly the blasted thing. This is being hampered by my discovery a few weeks ago that surgery to remove a carcinoma on my temple has left me with a slightly droopy eye, which tends to close when I concentrate, like when I type - or land a model aeroplane.

This was made clear on a recent Sunday flying session when I found myself completely unable to hit the strip without outside assistance as my depth perception was gone. Tbh it's knocked my confidence a bit, so I think I'll get the old Apprentice foamy going again until I'm happy with my own flying. In the meantime I'll probably get one of the instructors at the club to maiden it to see if it works as I hoped. I'll report back in due course.

Kim

[Rich too]

Posted by brokenenglish on 22/08/2016 21:15:15:

Posted by cymaz on 22/08/2016 21:07:57:

Posted by Rich2 on 22/08/2016 19:31:02:

Good stuff. As a matter of interest what tx battery are you using? I changed mine for a Lipo and it lasts for ever, it's brilliant.

Eneloop 6v. As it has a rear servo need some extra nose weight

Isn't there some misunderstanding here?

Yes, I was referring to the tx!!

[cymaz]

Posted by Rich2 on 23/08/2016 19:12:45:

Posted by brokenenglish on 22/08/2016 21:15:15:

Posted by cymaz on 22/08/2016 21:07:57:

Posted by Rich2 on 22/08/2016 19:31:02:

Good stuff. As a matter of interest what tx battery are you using? I changed mine for a Lipo and it lasts for ever, it's brilliant.

Eneloop 6v. As it has a rear servo need some extra nose weight

Isn't there some misunderstanding here?

Yes, I was referring to the tx!!

oh heck........sorry. Eneloop 9.6v 2000mAh. Lasts quite a while but I do charge every 3 weeks or so