The importance of accurate location of the Centre of Gravity of a model cannot be understated.

Till now I was doing it the old-fashioned way - mark the CG points with a marker pen, and balance on the fingertips. While it works, there is always a chance for error (eg if one finger is at an angle!)

I saw a nice CG Balancer on HK, but the shipping was 2 X the cost! So, decided to make my own  

Used some scrap 9 mm ply, two 4 mm nylon screws, 2 X 4 mm blind nuts, 2 a M6 Nylon screws for locking the ruler, 2 pieces of Aluminum tube, and 2 X 12" wooden rulers. Total cost about Rs. 100 (plus a few hours of work  )

Set the screws so their tops are horizontal using a spirit level

2 wood pieces form the guides for the ruler. Need to ensure the rulers are parallel to the ground ie horizontal. I had some acrylic lying around, so I used it to look cool   Similarly, 2 small pieces of wood are screwed into the end of the rulers to form the LE Stoppers (ensure they are at 90 ^o to the ruler) I drilled and tapped M6 holes in the acrylic for the locking screws

Calibrate the location of the M4 screws such that the edge of the acrylic (or wood, if you use that) shows a direct reading of the distance of the vertical stopper (which contacts the leading edge of the wing) from the centre of the M4 Nylon Screws. ie it shows distance of CG from the LE



In the picture above, note that there is a 1" 'zero error' built in to accommodate the stopper. So if the ruler reading is say 5" it means the actual distance from LE to CG is 4"

Testing on a 2.2 Kg .52 size Nitro model

The completed set-up



Model balanced level



Take the reading

Finish by painting

Some dimensions:

15" (380mm) clearance between measurement points and surface ie height of Wing bottom from ground.
Maximum 10" (254 mm) width between measurement points (adjustable by moving the ply ends on the Aluminum tubes)
This can measure about 10" from the LE, ie a wing chord of about 30" max.

Other notes:

Make it rigid. This is important! I used self tapping screws for all joints

Sir, you could have done a T shaped stand instead of L. It would avoid any tip over to the rear, if the model was tail heavy. Just occurred to me.. I love the colour combo :thumbs-up:

Since the model will balance on the M4 nylon screws it will not tip over. T will be overdesign

Glad you like the colour

If you observe carefully, it is not really an 'L'; more like a 'Z'

Oh yes! I didn't see that.. And those books.. cannot be able to beat you anytime

Nicely done and beautifully finished. Nice to see home built tools. 

Thanks Ashok-ji

It's nice to see old fashioned DIY with today's RCers. Sadly there's too much buy it and if anything goes wrong, buy another one. This example of building your own is excellent, even if it is a copy of what's available. Someone has taken the time to save their pennies and give the finger to big business.

Actually I've noticed India has a higher percentage of DIY than most countries. In many of them a good RCer is based on how many planes he has, not how many planes and accessories he built himself. Well done sanjayrai . It makes my HobbyKing unit seem flimsy.

Thank you Propfella. Hope you are keeping well