My WOT4 MK2 Owners - Help me balance my model

[250quadguy84]

Hi there,

Just finishing a model and not quite sure exactly where the balance point is, I have read the instructions but its not 100 clear and as a new builder im not quite sure. Also, whats the best practise with balancing, and where and how do you add the weights?

In the book it says

COG should be 82mm back from the leading edge of the wing at the root, this should be measured with the fuel tank empty.

Could someone kindly point out to me where this is? Any info on balancing would help a lot

Thanks

[ken anderson.]

hello darren---the root is where the wing is joining the fuselage measure 82mm back from the leading edge(the front)...with the fuel tank empty the model should balance there...if the nose go's down slightly that will be ok...if the tail go's down slightly it will be Very responsive to the control inputs......so you will have to add weights(normally bit's of lead)...on the tail end i would use the 'sticky' type's that come in 5g or 10 g pieces...in the front you can use any bit of lead ...put inside beside the fuel tank......as i say-if it's nose heavy-slightly-dont worry...if it's tail heavy.....add some lead to get it nose heavy/ish...

 

the way to do it - is to have the 82mm marked on both sides of the wing and get the model to balance on them mark's...hope this is some help to you..

 

ken anderson ne..1. (tech dept)

[Gary Binnie]

I'll try!!

 

Turn your Wot 4 upside down and run a finger along the front of a wing until you hit the fuselage, that's the 'leading edge at the wing root'. Measure back 82 mm and either add a small felt tip pen mark or a very thin line of coloured tape (line goes from the fuselage side towards the wing tip, half inch long will do).

 

Do the same for the other side.

 

Turn the model up the right way and lift it with your index fingers on these marks, you are looking for the model to sit slightly nose down. If it sits level or tail down you will need to add some weight to the nose, as far forward as you can get it.

 

Not had a Wot 4 but Chris Foss models usually balance without any extra weight if the radio gear (especially the battery) is in the right place.

 

Let us know how you get on.

 

GB

[250quadguy84]

Cool thanks for the help both, if I do need to add weight, can I just install this under neath the foam in the radio bay around the fuel tank area? that should be ok right?

 

I will give this a go tonight.

[Gary Binnie]

Yep, or tape it to the battery and wedge it all under the tank with the foam. The further forward you can get it, the less you will need (keeps the overall model weight down).

 

There is another balancing act that you could look at and it might be mentioned in the instructions, lateral balance. Simply, this is checking if one wing panel is heavier than the other. I only bother with power models if they don't seem to fly straight (skewing out of loops), I do check it with gliders as the longer wing span (moment arm) has a bigger effect.

 

Make the same 82 mm marks (temporarily on masking tape) on the top of the wing, find a six inch stick of hardwood and tie a piece of string to it. Attach the stick to the wing with rubber bands (stick lying along the marks, string on the fuselage centreline) and then dangle your Wotty in the air.

 

If one wing is heavy it will fall to that side (add a penny with tape to the other tip), it will also show you if the longitudinal balance (that you checked earlier on your fingers) is correct.

 

Cheers

 

GB

[250quadguy84]

Thanks! One last question, I will try and get hold of some lead, however can something be used which equals the same weight? IE maybe some coins stick together?

 

I know I would need a lot of coins as lead obviously weighs more, I might be able to find something at home to use as a weight.

 

 

Edited By Pete B - Moderator on 18/07/2018 23:01:39

[Gary Binnie]

Yep, the only reason we use lead is because of its density we need physically less of it.

 

I have used nuts and bolts and even metric sockets!! I will be surprised if you have to put much if any weight in. If you are using an engine in the range that Chris suggests and the radio gear is where he says to put it then it should fly straight off of the building board (but we still need to check!!).

 

Sometimes it's possible to move the engine backwards or forwards on the bearers to adjust without using any weight. The Wots-Wot biplane has swept or unswept wing options to cater for different weight engines and I think the fuselage nose can be made shorter as well (long time since I built it). Mine has one swept, one straight but don't tell Chris!!

 

A lot of people use stick-on wheel weights, come in 10g chunks, possibly from Halfords.

 

Here's my Wots-Wot, there is one dot for the balance point under the top wing and I struggle to lift it on one finger as it is a winged manhole cover (glassed all over and weighs a ton!).

 

[250quadguy84]

Yeah I was thinking about moving the engine back or forth, however unfortunately one of the exhaust hex screws have rounded, so I can't get it out, I am just going to use weights (if I need to use any)

 

Will be checking tonight

 

Will let you know how I get on.

[250quadguy84]

I have just marked the points and balanced using my two index fingers, the model has a very slight nose down balance, looks good?

 

Edited By Pete B - Moderator on 18/07/2018 23:02:20

[Biggles' Elder Brother - Moderator]

Yeap, that sounds fine.

 

BEB

[250quadguy84]

I didnt actually add any weight's or anything, I just put everything on/in including battery/radio gear etc etc, tank empty, put wings on and screwed in

 

Good to know

[Gary Binnie]

Told ya!! Good stuff.