The Vector is going towards the circle

[Kafin Noe’man]

I have set my Vector to have an engine out thrust and rudder offset, but unfortunately the plane was losing its tension immediately and going inside towards me in the circle. The engine is ENYA 35x and I launched it at around 10,500 RPM. What could be the problem?

[Joe Gilbert]

Is it durning take off roll on in the air. On ground roll the inside wheel may not turning properly ,inside might be binding up as you pull on lines while rolling to take off or wheels turned in a bit. Take a nice pice of wood drill a hole through it to fit the engine prop shaft and bolt it on and measure carefully from tip of stick if can eight inches out to flap line edge of wing then  rotate to other side and measure it ,to be very sure you don’t have I bit of in thrust. Not enough tip weight can cause that to happen also. When starting to take off if you position yourself a foot or two in front of aircraft and call for the release you can lead and walk with plane a step or two it to keep your self out in front of plane till it gets some momentum. Lead the aircraft keeping some pressure on leadouts to pull inside wing in front of outside one. It is no good to have a plane want  to come in circle while flying. 

PM me and we can talk if that would help.
Joe Gilbert

[Ken Culbertson]

What is it doing after you recover from takeoff?  What Joe has suggested is something I do on all of my planes.  Walk with it then move back to center after it has made the first lap.  Also check the angle it is sitting at on the ground.  The outboard wing should be a bit lower.  Also check the ground roll.  If it is rolling in that may change the angle it is taking off.  Walking helps that one too.

Ken

[Motorman]

Could be allot of things. Do you go nose up too fast on take off? The engine will torque roll the plane right at you. Must take off flat. Does your wing have a bad warp with the out board trailing edge down and/or the in board trailing edge up? Does your out board flap drop down more than your in board flap? Do you keep the lines tight after release? Are the lines catching on the grass? Are you taking off down wind? Did you rake the lead outs back enough?

Motorman

[Air Ministry .]

What could be the problem?

Undercarrage alignment ? use a fingertip to roll it forward on a level surface . Shouldnt be springy or wobbly .

TIP WEIGHT . puttet upside down on the bench . press inboard tip to bench . ( fingetip again . ) it should clonk or clunck to outboard tip , if it hesitates its got to little .

SIT it on a bench level . stand 3 or 5 metres forward . block an eye and find the neutral line of the fin . Is it inline , inboard , or outboard . looking at the spinner centerline .
A piece of masking tape across behind the spinner - vertical stick and 1 inch packer - Mark with liquid marker ( or pencil / ball pen first ) do from other side . Disect . THAT should be spot on centerline . do at fwd . flat sides / cylinder . For Eyeballing the fin .

Or just walk backward on the launch . Some Planes youve GOT TO . ( we are assuming the wings not twisted & stab. is level with it . Eyeball the whole shooting box from well aft . And check Elevators both unbent
and flaps . As in look at the top surface Ea Side and see theyre dead weven aligned . NOT one up one down , as that'd roll it .

Got any PICTURES .

[Air Ministry .]

You can see , if you held the tail up, or had your chin in the grass , youd see if everything was all square and ship shape . 
https://www.flight-mechanic.com/biplane-assembly-rigging/
The throwing BLOCKS around is a good idea . Pieces or lengths of say 1/2 Sq at the hingeline, you can eyeball for even step each side , at spar .
Or put strips fore & aft on them , equidistant out , and see if theyre parrallel . Pre War Aircraft Aeronautical stuff , RIGGING was  Standard .
Proceedure still matches . Stringlines plumbobs and levels . accuracy and sight lines . Gaps to flat bench equal . Most guys have a plate glass sheet.
Old table top or scrap from glass cutter . eveven a 18 in x 5 foot is good . 4 ft x 5 ft isnt bad .

ALL the PLANES must ALIGN > !

https://www.wondersofworldaviation.com/rigging.html

[kevin king]

I have a plane that has a warped wing and it does the same thing. I just back peddle until centrifugal force keeps the plane on the outside of the circle where it should be.
Kevin.

[Steve Helmick]

With a new plane, I think it's wise to start with too much tipweight for safety. It's easier to reduce the tipweight than it is to rebuild a broken airplane. As the model is accelerating, the tipweight causes the plane to yaw outward.  Steve

[Perry Rose]

On a paved smooth surface push the plane and watch it as it rolls away. It should roll in a straight line.

[Ken Culbertson]

Most of the replies, including mine assume a paved circle or short, well kept grass.  I think you are flying on rough grass.  If you are the rules are a bit different.  The torque roll from taking to the air with thrust instead of lift from the wings will cause this.  I have not flown off of grass much in a long time so take the advice from others over mine and if there is disagreement listen to them.  What Joe suggests works on grass as well you just need to do it more.  The Vector is similar to the Banshee in configuration and close in size so you just need to do what you are doing only more aggressive.  The key is to keep the lines tight by walking with the plane and perhaps backing up some if they start to loosen and stay off of the controls, especially up, until you have tension.  I also angled my LG to put the outboard wing down.  You also want to position so that you break ground down wind or slightly before.

Ken

[Air Ministry .]

Yep ,

On GRASS you need to lead with an extended arm , and back step 3 or 4 getting underway . 1st quater lap is the danger point .
You want to EASE it off the deck and keep the nose low . a leap into the air gets the tourque reation , ' P ' ( if its accelerating 0
and Line Drag all combined .

On TARMAC / hard surface , the wheels want to track along the flight path - So its neither pulling or pushing ?  on the lines .

looking at team race takeoffs on U Tube might elp .