CG Setting Check?

[Soloraj]

I am about to buy my first aircraft. I understand that getting the CG right is critical. Can anyone advise me on how to check and set the CG on an Easy Star?

[chiadennis]

Hi Soloraj

Welcome to the world of RC modelling.

CG of all flying models are very critical. Most kit/ARF model will have some information on setup and CG position. These points are taken from the leading edge and close to the center or as near to the fuselage as possible. As general CG position, they are between 30 - 35% chord. This depends very much on the wing shape. You can read this link to understand more. http://www.geistware.com/rcmodeling/cg_super_calc.htm

Since this is your first plane, follow the instruction carefully. Manufacture of the model normally give you a slight nose heavy so that you don't get too sensitive on the controls. Remember too that CG is taken with all equipment and batteries inside the model. Also I would highly recommend you get help with some experience pilots to help you maiden it. It also give you a chance to ask questions and for them to check all the controls.

If you are staying around the north-east of Singapore, you are welcome to join me at Punggol Field Walk (PFW). We fly on weekend morning and evening.

[Blackite207]

OOI! Dennis,
I have known you for very long time and you never invite me to fly with you at ponggol......Wah Lau Eh!!!

[chiadennis]

OOI! Dennis,
I have known you for very long time and you never invite me to fly with you at ponggol......Wah Lau Eh!!!

No too open, only BR park for you.....

[Blackite207]

You very lucky my combat days are over...HAHA!

[randomtask]

You very lucky my combat days are over...HAHA!

Hehe, I've heard that before... Let's put tow hooks on our wings and have some flat land combat...

Adnan

[Sunstorm]

I am about to buy my first aircraft. I understand that getting the CG right is critical. Can anyone advise me on how to check and set the CG on an Easy Star?

Hello Soloraj, my recommendation is for you is, when building, do take special care of the building process and the CG. These would be in the build manual.

It'll also be helpful if you could tell us what type of Easystar you are getting - e.g. the Receiver Ready version or the ARF version or the RTF version.

The most common mistakes I have seen with easystar users;

1) prop is on backward

2) incorrect CG

[Soloraj]

Thanks Sunstorm,

Which version would you advise - RTF or ATF?

CG:
I've read the manual (on-line) and I see where to set the CG. However, I'm not sure what to do to measure it? Is there some sort of scale that can tell the builder where the CSG is?

[Soloraj]

Hi Soloraj

Also I would highly recommend you get help with some experience pilots to help you maiden it. It also give you a chance to ask questions and for them to check all the controls.

If you are staying around the north-east of Singapore, you are welcome to join me at Punggol Field Walk (PFW). We fly on weekend morning and evening.

Thank you for the offer to help. When I've bought and built the Easy Star I will let you know.

[chiadennis]

CG:
I've read the manual (on-line) and I see where to set the CG. However, I'm not sure what to do to measure it? Is there some sort of scale that can tell the builder where the CSG is?

If you feel like spending, there are CG gauge you can buy.

http://www.centralhobbies.com/Tools/alignment.html

If you feel creative, you can make using 2 triangle plywood.

Or free, you your fingers.

For me I make 2 triangle blocks and I rest my plane on the apex of the triangle to get the CG points

EG:
If the instruction say the CG is at 90mm, this is measured from the leading edge of the wings and as close to the fuselage as possible. So what you do is using a ruler, just measure 90mm from the LE close to the fuselage. Put your finger on these points (2 points one on each wings) and balance the model. Lipo all must be in the model (DO NOT ARM THE ESC).

[Sunstorm]

Thanks Sunstorm,

Which version would you advise - RTF or ATF?

CG:
I've read the manual (on-line) and I see where to set the CG. However, I'm not sure what to do to measure it? Is there some sort of scale that can tell the builder where the CSG is?

Just read this page. Hope it helps.

http://www.rc-airplane-world.com/rc-airplane-weight-and-balance.html

Also, like ChiaDennis has kindly mentioned, perhaps you can go down to Punggol Field Walk with your new Easystar and have them do 'flight checks' for you.

I would choose ARF though because I would want to use 2.4 ghz radios which do not occupy channels.

[Jack_Chen]

measure the CG from the leading edge of the wing. draw a line there to guide you. or you can put a sticker, or whatever to mark the spot.

Do it on both sides of the wings - port and starboard, close to the fuselage (body).

No need what fancy tools, use your fingers for quick gauge or 'aga-aga'. The plane will sea-saw a bit and if the CG is correct, will come to rest where your fingers are.

If it was nose heavy, it will topple towards the front.

If it was tail heavy, it will topple towards the back.

Some say, a bit nose heavy (a few mm) in front is ok for beginners.

I will say, a nice balanced plane is a joy to fly.

I have had the Multiplex Easy Glider which is like larger cousin of the Easy Star and have also the AXN Jet which is a cheap clone of the EZStar.

These planes glide well at slow speeds, so no need to make it nose heavy. And when you are able to progress further, the balanced CG will help you do aerobatics.