Tim Mackey Posted February 1, 2011 Share Posted February 1, 2011 I was asked recently about the model balancer I use, so have pointed him towards this thread. As everyone should know by now, getting the balance point ( or COG as its usually called ) is vital before that first flight. Other threads have discussed ways of finding the correct place, and thats a different matter but some models are just too sensitive to be simply balanced on stubby fingertips. Couple of pencils stuck into a wood base will often do, but then with lots of different models of different sizes and weights something better is needed. This was knocked up in an hour or so from some hardwood battens and a few lengths of threaded studding and some washers and nuts. Pictures should explain it all, but basically loosen the nuts, and slide the sides closer / further apart to suit the fuselage / wings. Strong and stable enough for most models, and with a couple of small tongues of aluminum or tin strip on the tips, very accurate results are possible. I remove the tongues for heavy models in case the weight marks / punctures the model, and just use the angled cut of the wood itself. Pictures to follow. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 1, 2011 Author Share Posted February 1, 2011 general view and scale another The removable tips bottom section Quote Link to comment Share on other sites More sharing options...
Marko Posted February 1, 2011 Share Posted February 1, 2011 Looks very sturdy Tim l bought one of those Great Planes ballancer sometime ago cant t get on with it ,seems to twist out of shape , this one of yours won'tcheers ........... Marko Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 1, 2011 Share Posted February 1, 2011 tres smart Tim! I have some batten hanging round the workshop, just need some suitable size studding and nuts from B&Q. I'll knock myself one of those up I think. BEBEdited By Biggles' Elder Brother - Moderator on 01/02/2011 14:44:22 Quote Link to comment Share on other sites More sharing options...
cymaz Posted February 7, 2011 Share Posted February 7, 2011 I made one out of bits of scrap wood. The dowls simply pull out and it took 10mins to build. Holds my 12lbs model with ease. There is a 12" steel rule as a guide Quote Link to comment Share on other sites More sharing options...
Ernie Posted February 7, 2011 Share Posted February 7, 2011 Hi Guys, I buy two bottles of pink wine (tavel is excellent) I drink the contents with my neighbour, who has an excellent collection of aero engine sounds on CD With a very sharp scalpel, I cut the tops of the corks to give me a sharpish cork edge. Corks back in the bottle, one each side of the Fuz, and (apologies to the moderator chappies) Robert est votre oncle ernie Quote Link to comment Share on other sites More sharing options...
cymaz Posted February 7, 2011 Share Posted February 7, 2011 I have a bottle of white and a bottle of red. Would they go well together?? Quote Link to comment Share on other sites More sharing options...
IanN Posted February 7, 2011 Share Posted February 7, 2011 Or In use... Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 7, 2011 Author Share Posted February 7, 2011 Yup, all perfectly do-ableI like the convenience of mine being free standing, but great to see the ideas...keep em coming Quote Link to comment Share on other sites More sharing options...
IanN Posted February 7, 2011 Share Posted February 7, 2011 Free standing is certainly more versatile, though the piece of liteply with a hole cut in it is obvoiusly the easiest and quickest to knock up (I don't claim any credit for that, btw - it came from a Pete Lowe RCM&E article) All of these are practical, and any of them are infinitely better than the "thumbs under the wingspar whilst squinting down the fus" scenario. We've all been there As you say, keep them coming Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 7, 2011 Author Share Posted February 7, 2011 Pete Lowe shows us his balancer in this months mag actually! Quote Link to comment Share on other sites More sharing options...
Barry W Posted February 8, 2011 Share Posted February 8, 2011 Now that we have low cost and accurate scales to 0.1 grams an alternative method would be to weigh the plane as with regular small aircraft. You would weigh the plane on the main wheels and then on say the tail wheel. You then take any fixed point say the leading edge of the wing and measure the distance from the main wheels to the LE and do the same for the tail wheel. Calculate the turning moment for the main wheels and tail wheel ( weight times distance). By simple calculation it is then possible to determine the position of the Cof G from the LE. When using this method the model should be weighed in the level flying position. This method could be of use with larger models espeically if they have swept back wings such as Wolfie's TSR2. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 8, 2011 Author Share Posted February 8, 2011 No use for models with no undercarriage though Barry - which account for more than 50% of my fleet. Hardly simple either -not for someone like me with a phobia about calculators LOL Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 8, 2011 Author Share Posted February 8, 2011 Huge apologies Mr Bott sir - I accidentally deleted your post. I maeant to hit the quote button, as I was about to ask should I alter my google "safe search" settings before googling for "Vanessa Rig" Anyway, heres Chris' post . "For big models some people use a Vanessa Rig. This hangs the plane on strings and a plumbline points to the C/G. Probably not worth it for smaller models but interesting and useful. Have a google of Vanessa Rig to see what I mean. (No it''s not Diana''s sister!) " Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted February 8, 2011 Share Posted February 8, 2011 lol Nope should be safe, it's a genuine name of a genuine C/G method. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted February 8, 2011 Share Posted February 8, 2011 I have two pieces of dowel with rounded ends in a piece of wood. I would post a picture, being a responsible person I do not want to be responsible for those who collapse in a heap due to excessive laughter or those who burst a blood vessel, raging about the poor levels of skill at the design and fabrication stages. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 8, 2011 Share Posted February 8, 2011 We have a similar arrangement to Timbo's in our clubhouse but I have to admit to using s on a regular basis with no disastrous results. Perhaps my finely contoured fingers are superior to the average modeller's but you're not having a picture of them either! I've just had a terrible thought! Thinking about it, I normally use my middle fingers and one of them is rather the worse for wear at the moment since its escapade with my lathe last year - am I going to need to build a balancer myself? Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted February 8, 2011 Share Posted February 8, 2011 Some great ideas here which apply to workshop balancing. In practice many problems arise later when the model has been flown a few times and may have become out of balance. This is especially true of electric ones where a hard landing or a bump in transit may easily misplace the LiPO. The careful among us who remove the LiPO during charging and transit (not me!) also really need a simple field balancer. On all my models I have two plastic headed pins glued into the wing underside at the balance point. I use ones with about a 6mm diameter head and it takes only a few seconds before every flight to quickly test the CofG using the pointed-finger technique. Not super accurate I know but plenty good enough to tell if things have gone awry. No more peering under the wing to see those marker pen lines! In the field, after the first few try-balances it becomes part of the rigging/channel check/Tx on routine and one day - may just save a model. Peter Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted February 8, 2011 Author Share Posted February 8, 2011 Great idea. Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted February 9, 2011 Share Posted February 9, 2011 Posted by Grasshopper on 08/02/2011 16:07:21:Some great ideas here which apply to workshop balancing. In practice many problems arise later when the model has been flown a few times and may have become out of balance. This is especially true of electric ones where a hard landing or a bump in transit may easily misplace the LiPO. The careful among us who remove the LiPO during charging and transit (not me!) also really need a simple field balancer. On all my models I have two plastic headed pins glued into the wing underside at the balance point. I use ones with about a 6mm diameter head and it takes only a few seconds before every flight to quickly test the CofG using the pointed-finger technique. Not super accurate I know but plenty good enough to tell if things have gone awry. No more peering under the wing to see those marker pen lines! In the field, after the first few try-balances it becomes part of the rigging/channel check/Tx on routine and one day - may just save a model. Peter Do exactly the same, though I use the cheap sewing pins from the £1 / 99p stores, with smaller heads about 1/8" Got the idea from a book in the 70's (though I think the idea there was to use pins to give your fingers the right place) I think the book was by David Boddington, the hard cover was printed (no dust jacket) had a white background with dark red / burgundy type. Must dig it out of the box in the garage someday ! Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted February 9, 2011 Share Posted February 9, 2011 Interesting Steve - I don't remember seeing this idea anywhere but just seemed to start using the method many years ago. I suspect it has been around you years and just pops up from time to time. Another method I have started to use with fibre-glass winged gliders and small foamies utilises the small (8mm dia) rounded 'pips' of softish plastic which are commonly used as bumpers to stop kitchen drawers slamming shut. These are self adhesive and stick like sh*t to a shovel: they can be bought at kitchen suppliers, B&Q etc. Peter Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted February 9, 2011 Share Posted February 9, 2011 Posted by Grasshopper on 09/02/2011 08:37:57: Interesting Steve - I don't remember seeing this idea anywhere but just seemed to start using the method many years ago. I suspect it has been around you years and just pops up from time to time. Another method I have started to use with fibre-glass winged gliders and small foamies utilises the small (8mm dia) rounded 'pips' of softish plastic which are commonly used as bumpers to stop kitchen drawers slamming shut. These are self adhesive and stick like sh*t to a shovel: they can be bought at kitchen suppliers, B&Q etc. Peter Yes, you are probably right. I'm sure I have seen it somewhere in the last year as well, but can't remember where. All my Multiplex foamies have it, I uct the pins so that they are only about 1/2" long and put them in with a little CA. Like you say ,it becomes a routine part of a pre-flight, if something is horribly wrong, you can see in an instant. I didn't mentioni t before as the talk was of devices. You can see mine hear on the funcub in a hpoto I uploaded in October Quote Link to comment Share on other sites More sharing options...
cymaz Posted February 9, 2011 Share Posted February 9, 2011 Got any spare Model Technics Trim Line or coloured solar trim and put a line on the underside of the wing on the c of g. Quote Link to comment Share on other sites More sharing options...
Robin Kearney Posted April 18, 2015 Share Posted April 18, 2015 Thanks to Tim for the photos of your balancer. I found this old thread through google. After the last two (scary) maiden flights my previous 'finger tip' balancing has been deemed insufficient, so I've followed your design and knocked up the rough and ready jig you can see below. Many thanks for taking the time to pop some photos of yours onto the forum Tim. Quote Link to comment Share on other sites More sharing options...
IanN Posted April 18, 2015 Share Posted April 18, 2015 There's another variation on this theme in the latest (May) RCMW Quote Link to comment Share on other sites More sharing options...
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