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Electric Acro Wot ?


Jon
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Thanks for the nice comments chaps..

re the foam... Tom ....  Yes I to would like to do away with the stuff....so do you always land very gently  and thus don't need foam ?  ......or how do you secure all your pricey bits ?

Jon 

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Hey Jon, while doing an outside loop with a MPX Gemini, the battery ejected itself taking the ESC with it. The model went into a perfect inverted spin and crash landed gently only breaking the prop, the battery and ESC were retrieved from a small depression in the soft ground after a police style search with the other club members and to cut a long story short its all back together with some better velcro to keep the battery in place.

So to answer your question, the rx is velcroed, so is the battery and the esc might get strapped down or just float about a bit in the fuse. Keeps all these bits nice and cool!

Cheers,

Tom

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Sorry to hear about that Tom...but I lost a Lipo that cost over £100, it too tried to fly away from the plane on its own, so now I'm thinking of fitting parachutes to them

Yep...I agree, Velcro wont stop the air flow but should it not have stopped your battery from doing its thing?

No, I'm not taking the ....P!%!!... but surly there has to be a better way ? or is it just a compromise between the two...?

One idea I had was to use lots of paper drinking straws but our local schools have stopped issuing them now as they no longer give out the 3rd of a pint  milk bottles at play time showing my age now.

I'm always ready to learn, so may be there are some better ideas out there?  

Jon 

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Next question is... anybody got any tips about how to glue the Acro Wot wings together?

I have the glass cloth and some 15 min Epoxy ready but have never had to spread epoxy over such a large area before.

Nor have I ever used fiber Glass  

Is 15 min Epoxy to fast for this job? is it ok to apply a little heat to keep it soft while I smooth it off?

Any links on this forum to where this subject maybe covered?

Jon 

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The wing joining bandage is only to cover the centre section and about an inch or two either side of the actual joint. I use 30 minute epoxy on this part of the job.

Dont fuss too much about the appearance of it, as it will be virtually invisible once the wing is fitted to the fus.

I take it the joining is what you mean Jon? - and not glassclothing the whole wing ? If indeed you are contemplating glassing the lot...then I must ask  - why ?? 

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Thanks Timbo

No, only the join is to be glassed. My only concern was could I do the job with 15 min Epoxy or do I need to buy some 30 min. You have answered my question. more cost!

In the acro wot kit I have found the glass matting but in the instructions there is a mention of a 2nd tape that needs to be applied first, I have no idea wot this really means.. its not talking about the 2 strips of masking tape which protect the rest of the wing while glassing only to be removed once the glue is dry.

I think it means that I should use a 2nd supplied tape to hold /join the 2 wings together while glassing. but there is not any such tape in the kit.... So I plan to use a thin strip of Duck tape to keep the wings firmly fixed together while I apply the Glass and epoxy over it. Wot say you?

I look forward to you comments...

jon

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Personally I wouldnt bother ( I have built at least 3 Acrowots and probably more Wot 4s over my time ) and the procedure I followed is simply to join the wings first with epoxy at the roots....obviously ensuring exact alignment.

Then the next morning, apply a single reinforcing bandage with the slower set epoxy ( it is stronger than the fast cure stuff ). Once dry, I gently file off any high spots, and rub smoothish with fine glass paper, not removing too much epoxy of course ! Once covered with shrinkfilm it will hardly be noticeable. I have managed to break a few wings over the years, but every one has always broken at the edge of the bandage NOT the main joint, which is testament to the system being plenty strong enough. Obviously, be sparing with the epoxy as weight is your enemy as you know.

I find most models final AUW is not so much to do with the actual construction technique, and more to do with how empty the glue bottle is after finishing! 

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Thats fine Jon, and again..... well done the model is looking great - such a pity so many other people do not take the care and time to do the job right - especially with electric. A LOT of the reasons that people fail with their first electric models is down to simply not researching the equipment properly first, and buying something completely unsuitable or mis-matched.
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Well as I understand it this forum is for you OLDENS to teach us youngens (saying that makes me feel so good) , so If I dont ask daft questions I will do daft things which will cost me daft sums of money, cheaper to I ask daft questions

Thanks from Not so daft Jon! 

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In my kit, bought earlier this year, there was an erratum  slip saying the second piece of glass tape was no longer supplied - IIRC it said that it had proved unnecessary.

Mike

PS - Don't try to use the bandage at the joining stage - join the wings using slow setting epoxy and lots of masking tape or the like to ensure that they stay in register each with th eother. Only add the tape - again slow epoxy - when the joint is cured. Takes longer, but saves much bad language!

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  • 3 weeks later...

Hey Jon hows the Acro Wot coming together, do you have an All Up Weight (AUW) and final power figure (measured using a multimeter in between the battery and ESC, with the motor WOT and suitably restrained) yet?

Have changed my mind over an Xtra Wot (too big for my bicycle trailer and needs a monster field battery for re-charging) and might try an Acro Wot instead.

Cheers,

Tom

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Hey Tom

Hold on Hold on one thing at a time I had to stop work I have had a few probs...

1. Wife and I went caravanning (YES I SAID CARAVANING) in North Yorkshire ( she wanted to see her relatives, cant think why... Yes it was when all the snow came... did we have a good time, don't ask..oh yes it was very pretty

2. When we got back I got bitten by this (see pic) VERY DEAD NOW house pet.. not funny and very painful too... Seem there are many of them here in the south... they are form the Black Widow family!

3. Also have started work on a house we have just purchased, not much to do...see pic

So while I have had little to do between Hospital visit, digging ourselves out of the snow and busting my hand while demolishing a wall I have managed to join the wings and apply some covering to them... I'll put some pics up soon..

As for the electrics Tom... they all work but no real tests done as yet.... watch this space...

ok about the Extra wot, yep batteries are needed or maybe you could invent some wing shape solar panels that could do the job!

/sites/3/images/member_albums/29596/Dsc00208a.jpg

This lille S%d got me on the neck while I was a sleep, should have stayed up and work on the E-Acro!
/sites/3/images/member_albums/29596/DSC00213.JPG

not much to do as I said!
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Jon's tread and others have inspired me to have a go at converting my old Acro to electric. Previously powered by Laser 60, the fuz is clean with little or no fuel damage, just the yellowed paint needs a freshen-up. Sadly the wings have not fared so well, suffering from Foss's disease, the doped and painted tissue covered veneer resembles corrugated cardboard.

The veneered foam wing accounts for over half the airframes mass, so a built-up replacement is planned and I think an AUW sub 6lb should be achievable. Being built as the short nosed version I will need some weight up front, so a 6 cell A123 should help.

My proposed power train is a Turnigy SK plugged into a Plush 60A along with the aforementioned 6 cell A123.

What do the panel think?

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Good.

Wont be ballistic on 6s M1s, but then the gorgeous Laser engines were never really crowned by the 60 !

The Plush ESCs are great....make sure you get genuine A123 cells for best results.

Is your charger / PSU up to the job of 15 minute refuelling ? ( around 200+ watts required and 21V @10A or so ) 

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Farther Christmas has already been to my house.... but I have no idea how he got it down the chimney with the wings on?

Its seems to have been a long time but its finally built..... it will get its preflight tests over the next few days and as promised will put them up here but then it will be back to praying for good weather once more...

After much care rubbing it down I started covering it... never done this job before so practiced on an old bit of balsa first... Quite please with the final result but since the iron was a bit to big to apply heat to some parts I heated up an old hacksaw blade which did the job just fine and I even managed to find a "E" to put in front of "acro"

Any advice on how to set/fix the motor at the correct offset. Its mounted on 4 long bolts as one of my previous pics shows... I can wind the nuts up & down the bolts to offset it but how do I judge it?

/sites/3/images/member_albums/29596/Dsc00215ab.jpg



/sites/3/images/member_albums/29596/Dsc00220ab.jpg


No that's not Farther Christmas its a good looking young chap called me!

MERRY CHRISTMAS ALL

Jon

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Looking good. You have done a craking job with that Jon. You should be well pleased.

As far as thrust lines go I would start with something like 1to 2 degrees of RH side thrust and 1 to 2 degrees of downthrust.

Now you can go to great lengths to set this up . I would just make sure I have a litle bit of down and a little bit of right buy just looking at it,from above and from the side.  You can then fine tune this after a few flights. As long as you have not got up thrust and Left hand thrust you will be fine for your maden flight.

Would love to see it fly

simon

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Thanks Simon... A bit of right hand down eh! no problem.

I just hope I don't total it on its maiden that's all... I will not be adding up the cost of the total build so that I don't have too many tears or fears, if and when it should happen but I shall know its worth to me by just taking my pulse during its first approach and landing !

Still I didn't build it to just look at it, did I? so roll on some good WX and lets get my pulse pumping

jon

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