Excellent explanation of CoG Tim - but what about kit built biplanes? Can you just take 20-25% of the distance from the leading edge of foremost wing and the trailing edge of the aft most wing?
Tim: Yup, you got it. CG is 20-25% of the total distance back from the leading edge of the top wing to the trailing edge of the bottom wing (assuming a forward stagger). Good luck! Tim
I'm still building my foam board jet . It's large with a 1200mm wing span and swept delta type wing. That I mentioned before. I used this method and the cg appears to be spot on. With plenty of room to move my battery pack around and install the rest of my electronics. Thank you for explaining it in an easy to understand forum.
Very good information..Good instruction. You must have been a flight instructor. I'm in the process of building my own . I'm use to having it in the instructions so I didn't know the method of finding cg on a scratch type build. Thank you. I feel confident now that I can do it myself.
Thanks for the advice. I just installed motor,esc,receiver to the quick oat, waiting for the battery. The wing cord is 17 cm. Will try to balance at 4.5 cm. Leo.
I found about cg on a yacht on a trailer, engine in back, I got up on the trailer and the boat did a wheely. LOL! My buddy told me to put jack stands on the back of the trailer. Yeup Cg is important for the big birdies and the small ones. Weight "x" Arm "=" moment if I remember my flight training from the 80s...
Hi Tim. Thanks for the excellent informative videos. I have a question regarding calculating CoG, if the wing has ailerons to you include these in the calculations?
Mark: Yes, the (strip) ailerons would count as total wing area for CG calculations. Measure from wing leading edge to the trailing edge of the ailerons, CG around 25% back from LE. Tim
Thanks for the video. I'm building a foamboard, straight-wing aircraft, v-tail with flight controller installed and had been planning a 30% c.g. Do you reckon that's too far aft? Is 20% considered a forward-most c.g. and 25% an aft-most for most aircraft? Glad I watched this.. If I could subscribe again I would! :)
Olgoz: For our lightweight RC models, the CG range is not super critical. 30% back from wing leading edge should be OK, maybe a bit sensitive in pitch. If you want to play it safe, add a bit of nose weight for initial flights to keep CG at 25% point, then slowly remove weights a shift CG aft. Tim
I have a question. Since crashing a couple of my foam high wing models (carbon cub s2& Umx timber x) , the cg has changed after repairs substantially. I've added stick on lead wheel weights. Now my planes don't fly as well due to all the excess weight. What can I do to counter this if anything at all???
Hello Tim, do you have a video on how to find the CG on a biplane with staggered and tapered wings ? I looked through your video's but did not find it ? Many thanks !
Werner: Here is my video on swept wing CG ruclips.net/video/GeYuAbZmDYQ/видео.html For the stagger on a biplane, just measure 25% back from the top wing leading edge to the bottom wing trailing edge, that should be your CG. Think of the two wings as one big wing. Tim
Thanks Tim, so if I understand correctly I take the width of the root from the front of the top wing to the end of the bott wing and do the same for the wingtips and then apply your formula for swept wing using these 2 values and apply the result to the top wing to balance the plane ? Just want to be very sure as this is my first f3a plane, it costs a lot so the math must be perfect. The plane is a Sebart Prometheus F3A biplane (images.app.goo.gl/WWTCdaWmRh8Br8eb8)
@@wernervandenbosch1609 Yes, that is correct. And if you wish to be a bit more conservation, consider making the model a bit more nose heavy with the CG as far forward as 20% back from the leading edge. As you get comfortable with the model, you can move the CG back aft a bit, to the 25% back from LE mark. Tim
Excellent explanation of CoG Tim - but what about kit built biplanes? Can you just take 20-25% of the distance from the leading edge of foremost wing and the trailing edge of the aft most wing?
Tim: Yup, you got it. CG is 20-25% of the total distance back from the leading edge of the top wing to the trailing edge of the bottom wing (assuming a forward stagger). Good luck! Tim
I'm still building my foam board jet . It's large with a 1200mm wing span and swept delta type wing. That I mentioned before. I used this method and the cg appears to be spot on. With plenty of room to move my battery pack around and install the rest of my electronics. Thank you for explaining it in an easy to understand forum.
Glad you found the correct Center of Gravity . . . super important as you point out. Good luck!
Very good information..Good instruction. You must have been a flight instructor. I'm in the process of building my own . I'm use to having it in the instructions so I didn't know the method of finding cg on a scratch type build. Thank you. I feel confident now that I can do it myself.
And thanks for checking in! Tim
Bravo, Outstanding: Thank You for sharing your knowledge on this wholesome family friendly hobby. Cheers, Brad
Brad: Thank you kindly! Tim
Great explanation, thank you! I remember a 747 that crashed on takeoff out of Afghanistan. The cargo got loose and the weight moved aft. Horrendous!
Carlos: You are sadly 100% correct. Video taken by a US vehicle. B-747 pitched full nose up, followed by a horrendous crash. Tim
The video thumbnail picture incident happened at the same location as the 747 crash.
Thanks for the advice. I just installed motor,esc,receiver to the quick oat, waiting for the battery. The wing cord is 17 cm. Will try to balance at 4.5 cm. Leo.
Leo: Very good, thanks for this update. Missed you at the field today, perfect weather! Tim
Tom, Great video, that most any of us can understand.
Dan: I appreciate that! Tim
I found about cg on a yacht on a trailer, engine in back, I got up on the trailer and the boat did a wheely. LOL! My buddy told me to put jack stands on the back of the trailer. Yeup Cg is important for the big birdies and the small ones. Weight "x" Arm "=" moment if I remember my flight training from the 80s...
Free-Bird: Roger that! Tim
Very good explanation! Greetings from Bavaria!
Madmac: Thanks for checking in . . . and I always enjoy my time visiting your lovely Bavaria! 😁 Tim
Thank you for a great video!
👍🏻😊 Tim
The thumbnail airplane caught my attention, I was there for that incident.
Hopefully no one got hurt. Tim
I have become interested in vintage free flight models. Many have their CG well back. Why is this and how do they fly so well?
The vintage models had a "flying stabilizer" with a distinct airfoil shape that created lift at the tail, thus the CGs being further back.
Hi Tim. Thanks for the excellent informative videos. I have a question regarding calculating CoG, if the wing has ailerons to you include these in the calculations?
Mark: Yes, the (strip) ailerons would count as total wing area for CG calculations. Measure from wing leading edge to the trailing edge of the ailerons, CG around 25% back from LE. Tim
Thanks for the video. I'm building a foamboard, straight-wing aircraft, v-tail with flight controller installed and had been planning a 30% c.g. Do you reckon that's too far aft? Is 20% considered a forward-most c.g. and 25% an aft-most for most aircraft? Glad I watched this.. If I could subscribe again I would! :)
Olgoz: For our lightweight RC models, the CG range is not super critical. 30% back from wing leading edge should be OK, maybe a bit sensitive in pitch. If you want to play it safe, add a bit of nose weight for initial flights to keep CG at 25% point, then slowly remove weights a shift CG aft. Tim
@@TimMcKay56 Thanks Tim! Will do just that
I have a question. Since crashing a couple of my foam high wing models (carbon cub s2& Umx timber x) , the cg has changed after repairs substantially. I've added stick on lead wheel weights. Now my planes don't fly as well due to all the excess weight. What can I do to counter this if anything at all???
Not much. The smaller models are very sensitive to any extra weight. Tim
Hello Tim, do you have a video on how to find the CG on a biplane with staggered and tapered wings ? I looked through your video's but did not find it ? Many thanks !
Werner: Here is my video on swept wing CG ruclips.net/video/GeYuAbZmDYQ/видео.html For the stagger on a biplane, just measure 25% back from the top wing leading edge to the bottom wing trailing edge, that should be your CG. Think of the two wings as one big wing. Tim
Thanks Tim, so if I understand correctly I take the width of the root from the front of the top wing to the end of the bott wing and do the same for the wingtips and then apply your formula for swept wing using these 2 values and apply the result to the top wing to balance the plane ? Just want to be very sure as this is my first f3a plane, it costs a lot so the math must be perfect. The plane is a Sebart Prometheus F3A biplane (images.app.goo.gl/WWTCdaWmRh8Br8eb8)
@@wernervandenbosch1609 Yes, that is correct. And if you wish to be a bit more conservation, consider making the model a bit more nose heavy with the CG as far forward as 20% back from the leading edge. As you get comfortable with the model, you can move the CG back aft a bit, to the 25% back from LE mark. Tim
Indeed, nose heavy is more an insurance than a problem. Thanks for your advice, duly appreciated !
Sir plz give me vedio how to find out Cg of f22 Rc model plans
Subrata: I am not sure how the designer did this, I just used the computed CG. Tim
@@TimMcKay56 plz tell me how
Sir, plz tell me which cg is best for new Rc beginers pilot, 20percent or 25percent . Plz reply sir
Subrata: CG at 20% a conservative good start. Tim
@@TimMcKay56 thank you so much sir
👍🇧🇷🇧🇷🇧🇷
👍🏻 Tim