Acro Wot ARTF (balsa) chat

This is how I modify the U/C to prevent the problem of ripping the bottom out of the acro wot, wot 4 and any other model with a similar arrangement. I use 6mm bolts and a plywood packer that is also about 6mm thick. The reason for this is so that when the bolts break and the heads come off there is enough thread to be able to get the remainder of the bolts out easily. Also use a small amount of cyno to fix the t nuts in otherwise they will work loose and you will have to remove the tank to get at them. nearly every one in our club has adopted this method as once the undercart are ripped out the tank bay is usually fuel soaked and never glues back with any strength.

This is the way I have modified a crashed acro wot to be able to electrify it. I haven't got any further with it yet as I cannot decide what power set up to use. I have 6s packs available so any ideas would be great.

Glenn

Hi Glen, I posted my electric conversion setup a couple of pages ago, but I've reproduced here for you. Please note the original post mentioned an Eflite Power 60, this was a typo, it should have read 'Power 52'.

"For anyone that's thinking of going the electric route, you may find that the supplied battery tray isn't of much use for a 6s set up (5s is recommended in the manual), and that you will most likely need to manufacture your own tray as I did. Also, as I elected to use an Eflite Power 52 the supplied stand offs were too long so I fitted my own adjustable units to achieve the correct spinner clearance . The AUW of my particular Acrowot with a 6s 4000mAh battery is 2.98 Kg (6.5Lbs) and has unlimited vertical performance using a Graupner G-Sonic 13" x 8" prop and an aerobatic flight duration of 5-7 mins, dependant on throttle use."

Thanks for that Glenn

I was going to fit 4 or 5mm nylon bolts, but I'll go with your setup and pop into my LMS tomorrow for 6mm with matching captive-nuts.

Clever idea the 6mm ply spacer. (My original plan for removing any broken studs was to heat up a parallel shank screwdriver and ram it into the stud fast enough to melt a slot!).

Undercarriage area of the fuselage now repaired, strengthened internally and improved with a 6mm spacer according to Glenn's method. Also took the opportunity to fill in the cut-out for 2-stroke exhausts, then re-covered in Profilm black... because I didn't have any yellow to match.

I did similar to Daniel to an artf Ripmax Wot4, light fibreglass epoxied to the ply floor and a couple of inches up the sides. Irretrievably damaged a succession of alloy and g/f undercarriages, but the fuze remained entirely undamaged.With hindsight if I'd used nylon bolts I wouldn't have even had to buy any replacement U/Cs either.

Glenn

Even assuming there was no 6mm packing piece on your undercariage, there are still ways to remove sheared nylon bolts. I heat up an allen key, then push it into the broken stub of the bolt. Wait for it to cool, then simply unscrew it......

Once it's out, heat the key up then remove it to repeat the process if necessary........

The new improved Glenn-system proved its worth today, when a dead-stick had me come down in the rough beyond the end of the runway.

I was able to remove the stud just by turning it with my finger tips - after the intact bolt was losened and the 6mm spacer removed.

Massive discovery today...!

I couldn't understand why on previous flights my Acrowot needed 2-3mm of up-elevator trim for normal flight.

So, before going up to the field today, I measured the incidence of the wing relative to the tailplane (decalage if you like), and discovered that the wing actually had 1 degree of negative geometric incidence!

So I quickly made up a temporary shim, 100mm x 30mm x 4mm aero-ply, which fits under the trailing-edge and is held captive by two holes through which the nylon wing-bolts pass. This creates a positive incidence of about 0.5 degrees, which is how I understand fully-symmetric wings should be set up for traditional (i.e. non-3D) aeros.

Model now flies beautifully, with no elevator trim needed at all.

But this really begs the question as to why Ripmax supply an ARTF which is so dramatically out?!

Mind you, when my LMS originally got the Acrowot in for me, I discovered the tailplane was entirely lacking the elevator halves!

Edited By Jonathan M on 11/03/2017 22:03:16

Well I have had mine for a few months now and I have to say I love the way it flys. I bought mine as a lower cost alternative to the xl version and I was worried I would miss having a larger model. But my standard size acro wot with a laser 70 is proving to be a very enjoyable model. Now the arft is manufacured to a price point and as it comes in the box it is ok but things can always be improved. I was thinking of buying a new kit and building it up with some improvements

building in a tank acess hatch

better quality horns and push rods

removing the covering before assembly and recovering with somthing better quality

is there anything else I should concider?

Edited By Phil 9 on 12/04/2017 12:48:17

I think the smaller one flys more excitingly than the XL. That said I'm gonna up the aileron throws and see what happens.

Rudder seems less effective on the XL than the standard one too.

well I thought I would re examine the fuel tank in my acro wot in the hope I could lower it.

this would be simple I thought as the stock tank flops about if unsupported there should plenty of room but there is not. if you pull the tank out from the fire wall recess it rests on the cut out in former 1 so can not be lowered without cutting out part of the former. As this former is used to attach the wings it can not be modified to a large extent

I cut a hatch into the tank bay of my acro wot.. You can easily see where the designer took the tank measurement to place former 1. we all know this was an error

it is just the way it worked out. For the most part I used mini servos and the engine is a laser 70

is it just me or is the engine mount that comes in the IC pack very soft there seems to be a lot of flex on mine

yes its just me. turns out the engine mounting bolts were slackening off even with lock nuts. I put a plain nut on first and then a lock nut together with some lock tite

Phil,

That's my formula- plain nut to mount then nylock to make firm.

S

This is my first IC model.

So do you set the CofG with an empty or full tank?

Can you feel the CG move as your tank empties in flight?