balancing corsair with retracts dilema
05-02-2013, 12:45 PM
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balancing corsair with retracts dilema
hi guys, well here we go, i'll give as much info as I can, have a corsair with a 56 wingspan, the manual states 95mm CG, I have 2 other corsairs and the balance point on them is nearly the same, 4-4and a quarter inches. the one i'm working on balanced perfectly at 95mm, while on my greatplanes balancer, I put a bubble level attached to a small piece of plastic on center of fuse, and the bubble is right in the middle, plane is sitting level, didn't have to add any weight, NOW! with the radio on, I put the gear up, and of course it goes tail heavy, if I add weight to counter it and bring it back to a level position, when they were down, then it will be way nose heavy, I use change as weights, qrts, nickels dimes pennys, if I add about 10 qrtrs, it brings back level, are you with me so far, if I add all that weight, and don't want to use the retracts, for a couple of flites or so its gonna be way nose heavy, how do you set it up so the plane flys good whether the gear is up or down, oh, I fly all my planes on 6 chnl futaba fm radios, oh and forgot this corsair is electric, running a 4 series 3300, but again it balanced, what kind of weight should I start with. right now it sits level, I know it should sit a little nose heavy. sure do need some answers, thanks to all.
05-02-2013, 02:09 PM
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RE: balancing corsair with retracts dilema
Hi
Balance it with the gear retracted the shift forward when landing is fine you may land slightly faster but it's a warbird after all!
Chris
Balance it with the gear retracted the shift forward when landing is fine you may land slightly faster but it's a warbird after all!
Chris
05-02-2013, 02:34 PM
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RE: balancing corsair with retracts dilema
ORIGINAL: jetdeck
hi guys, well here we go, i'll give as much info as I can, have a corsair with a 56 wingspan, the manual states 95mm CG, I have 2 other corsairs and the balance point on them is nearly the same, 4-4and a quarter inches. the one i'm working on balanced perfectly at 95mm, while on my greatplanes balancer, I put a bubble level attached to a small piece of plastic on center of fuse, and the bubble is right in the middle, plane is sitting level, didn't have to add any weight, NOW! with the radio on, I put the gear up, and of course it goes tail heavy, if I add weight to counter it and bring it back to a level position, when they were down, then it will be way nose heavy, I use change as weights, qrts, nickels dimes pennys, if I add about 10 qrtrs, it brings back level, are you with me so far, if I add all that weight, and don't want to use the retracts, for a couple of flites or so its gonna be way nose heavy, how do you set it up so the plane flys good whether the gear is up or down, oh, I fly all my planes on 6 chnl futaba fm radios, oh and forgot this corsair is electric, running a 4 series 3300, but again it balanced, what kind of weight should I start with. right now it sits level, I know it should sit a little nose heavy. sure do need some answers, thanks to all.
hi guys, well here we go, i'll give as much info as I can, have a corsair with a 56 wingspan, the manual states 95mm CG, I have 2 other corsairs and the balance point on them is nearly the same, 4-4and a quarter inches. the one i'm working on balanced perfectly at 95mm, while on my greatplanes balancer, I put a bubble level attached to a small piece of plastic on center of fuse, and the bubble is right in the middle, plane is sitting level, didn't have to add any weight, NOW! with the radio on, I put the gear up, and of course it goes tail heavy, if I add weight to counter it and bring it back to a level position, when they were down, then it will be way nose heavy, I use change as weights, qrts, nickels dimes pennys, if I add about 10 qrtrs, it brings back level, are you with me so far, if I add all that weight, and don't want to use the retracts, for a couple of flites or so its gonna be way nose heavy, how do you set it up so the plane flys good whether the gear is up or down, oh, I fly all my planes on 6 chnl futaba fm radios, oh and forgot this corsair is electric, running a 4 series 3300, but again it balanced, what kind of weight should I start with. right now it sits level, I know it should sit a little nose heavy. sure do need some answers, thanks to all.
You want to fly some flights that "don't use the retracts"? Why fly around with the gear down? Is it gear that plugs in and out of the wing?
If it balances level with the gear up, and that's at 95mm, then you're good to go. The rule is to balance models equipped with retractable gear with the gear up. Smart money balances level, not nose heavy. Balance it level and you know the CG is where it should be to insure a safe maiden CG location.
You say "it should sit a little nose heavy". No, actually it should balance level. How it sits doesn't matter. If you are saying "sit" and meaning "balance", the rule is still the same. With your balancer positioned at 95mm, the plane should be level. Start with whatever weight it takes to do that (with the gear up).
Good luck.
05-02-2013, 03:57 PM
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RE: balancing corsair with retracts dilema
Some planes,and plans balance with the gear up and some with the gear down. What do your plans say? +1 on balancing level provided the manufacturer got the CG,right. Troy built warns against esm ARFS recommended CG point. Just saying to be diligent. Nose heavy plane flies poorly, tail heavy plane flies one.
05-02-2013, 07:12 PM
#8
RE: balancing corsair with retracts dilema
Balance with the gear up. A tail heavy plane is way worse than one a little nose heavy for landing.
If you want less of a change, fill your tank (assuming it is not electric). put the gear up, and then balance. You should still be a little nose heavy but not as much.
If you want less of a change, fill your tank (assuming it is not electric). put the gear up, and then balance. You should still be a little nose heavy but not as much.
05-03-2013, 09:23 AM
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RE: balancing corsair with retracts dilema
When you balance a alcohol burner you balance with the tank empty. Then you add 10oz to the nose before you fly it, that makes it much more nose heavy than with your gear deployed. On landing you land with 2-4 oz left in the tank and the gear deployed so the CG is always be forward of where you have it if you balance with the wheels retracted. So for people new to electrics I suggest balancing at the recommended cg then adding enough wt to move it forward 1/8 to ¼ in.. but that extra wt needs to be easily removable so once you start to get comfortable with the plane you can remove that extra wt till you get her to fly the way you want her too.
If I want to tweak the CG like I just suggested I normally cut one peace of lead that accomplishes the movement I want then screw it to the firewall with a little CA on the threads then you can remove it at the field snip a quarter of it off and screw it back down with a little ca on the threads again.
I believe you will find that a 90mm balance point with the wheels retracted will be right what you are used too.
Joe
If I want to tweak the CG like I just suggested I normally cut one peace of lead that accomplishes the movement I want then screw it to the firewall with a little CA on the threads then you can remove it at the field snip a quarter of it off and screw it back down with a little ca on the threads again.
I believe you will find that a 90mm balance point with the wheels retracted will be right what you are used too.
Joe
05-03-2013, 12:49 PM
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RE: balancing corsair with retracts dilema
first off, to all members who have responded to my ?. I want to say THANK YOU!!!! one person asked what plane it was and well I didn't say cause I didn't want to hear any negative comments, but here goes, it is the 1450 corsair with flaps and retracts, electric powered, and retractable tail wheel, it has a 4 bladed prop, a 4 series 3300 lipo, and its from, are you ready, from NITROPLANES, shhhhhhh, ok, I balance it with the gear up, right, with the gear down it balances right at 95mm like the instrucions say,but when I balance it with the gear up and add enough weight to bring it back to 95mm, wont it be overly nose heavy, like say for instance I wanted to fly it with the gear down, maybe there is a problem with them not retracting, for some reason, instead of going home, can still fly, but it will be overly nose heavy, I guess when you balance it with the gear up, your committed to flying it that way, am I right? oh and yes the plane is epo foam, have had other planes from nitroplanes and all turned out to be good flyers, I also did swap out the servos, on flaps elev rud ailr, the retracts in the plane are servoless, and also has working gear doors and nav lights
05-03-2013, 01:53 PM
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RE: balancing corsair with retracts dilema
ORIGINAL: jetdeck
with the gear down it balances right at 95mm like the instrucions say,but when I balance it with the gear up and add enough weight to bring it back to 95mm, wont it be overly nose heavy, like say for instance I wanted to fly it with the gear down, maybe there is a problem with them not retracting, for some reason, instead of going home, can still fly, but it will be overly nose heavy, I guess when you balance it with the gear up, your committed to flying it that way, am I right?
with the gear down it balances right at 95mm like the instrucions say,but when I balance it with the gear up and add enough weight to bring it back to 95mm, wont it be overly nose heavy, like say for instance I wanted to fly it with the gear down, maybe there is a problem with them not retracting, for some reason, instead of going home, can still fly, but it will be overly nose heavy, I guess when you balance it with the gear up, your committed to flying it that way, am I right?
The model industry has worked out a rule they go by. They balance planes with the gear up. Doesn't matter if the gear goes inboard, outboard, aft or forward. Balance with them retracted. The CG location found with the gear up is more than safe enough to rely on even when it's changed the amount lowering the gear would move it. Lowering the gear won't change it enough that it matters. That's why the model industry goes by the rule that you balance models with the gear up.
Get over all your worries about whether it'll be unsafe flying with the gear down, or up. The center of gravity for safe flying with the gear up also gives safe flying when the gear is down and the CG shifts an insignificant amount. It will not be overly nose heavy. If it would be, the entire model industry and all of us experienced flyers would have come up with something else. There isn't a something else. Because the present way works great.
05-03-2013, 02:00 PM
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RE: balancing corsair with retracts dilema
Jetdeck. Welcome to the world of complex airplanes.... retracts, flaps...
If the instructions dont say specifically Id play it safe and balance the Corsair with the gear Up. Nothing says you cant experiment with the CG after you get some time on the model.
Gear on the Corsair are fun and do a couple things to the flight characteristics. With the gear down the CG is forward as youve found but the drag on the gear also causes the plane to pitch down some. There is No magic CG point that will change that.
What you'll have to do is trim the elevator in flight for the different flight mode; gear down or up. I can tell you for example that on my Corsair when the gear goes down I need 5 clicks of up trim to compensate. And vice versa when the gear goes up.
After feeling out the model over the first several flights, to lesson pilot work load I set up a gear to elevator mix. When the gear is lowered this P-mix automatically puts in a few % of up elevator for me. So I dont have to readjust the elevator trim every time I raise or lower the gear.
Let me add too that I have a NP F-18 90mm EDF. The gear on that plane is opposite. When the gear on that model is raised the model goes nose heavy. I believe because of the direction the nose gear swings. Again I use a P-mix to lesson my work load in flight.
Cheers.
If the instructions dont say specifically Id play it safe and balance the Corsair with the gear Up. Nothing says you cant experiment with the CG after you get some time on the model.
Gear on the Corsair are fun and do a couple things to the flight characteristics. With the gear down the CG is forward as youve found but the drag on the gear also causes the plane to pitch down some. There is No magic CG point that will change that.
What you'll have to do is trim the elevator in flight for the different flight mode; gear down or up. I can tell you for example that on my Corsair when the gear goes down I need 5 clicks of up trim to compensate. And vice versa when the gear goes up.
After feeling out the model over the first several flights, to lesson pilot work load I set up a gear to elevator mix. When the gear is lowered this P-mix automatically puts in a few % of up elevator for me. So I dont have to readjust the elevator trim every time I raise or lower the gear.
Let me add too that I have a NP F-18 90mm EDF. The gear on that plane is opposite. When the gear on that model is raised the model goes nose heavy. I believe because of the direction the nose gear swings. Again I use a P-mix to lesson my work load in flight.
Cheers.
05-03-2013, 07:41 PM
#14
RE: balancing corsair with retracts dilema
ORIGINAL: jetdeck
first off, to all members who have responded to my ?. I want to say THANK YOU!!!! one person asked what plane it was and well I didn't say cause I didn't want to hear any negative comments, but here goes, it is the 1450 corsair with flaps and retracts, electric powered, and retractable tail wheel, it has a 4 bladed prop, a 4 series 3300 lipo, and its from, are you ready, from NITROPLANES, shhhhhhh, ok, I balance it with the gear up, right, with the gear down it balances right at 95mm like the instrucions say,but when I balance it with the gear up and add enough weight to bring it back to 95mm, wont it be overly nose heavy, like say for instance I wanted to fly it with the gear down, maybe there is a problem with them not retracting, for some reason, instead of going home, can still fly, but it will be overly nose heavy, I guess when you balance it with the gear up, your committed to flying it that way, am I right? oh and yes the plane is epo foam, have had other planes from nitroplanes and all turned out to be good flyers, I also did swap out the servos, on flaps elev rud ailr, the retracts in the plane are servoless, and also has working gear doors and nav lights
first off, to all members who have responded to my ?. I want to say THANK YOU!!!! one person asked what plane it was and well I didn't say cause I didn't want to hear any negative comments, but here goes, it is the 1450 corsair with flaps and retracts, electric powered, and retractable tail wheel, it has a 4 bladed prop, a 4 series 3300 lipo, and its from, are you ready, from NITROPLANES, shhhhhhh, ok, I balance it with the gear up, right, with the gear down it balances right at 95mm like the instrucions say,but when I balance it with the gear up and add enough weight to bring it back to 95mm, wont it be overly nose heavy, like say for instance I wanted to fly it with the gear down, maybe there is a problem with them not retracting, for some reason, instead of going home, can still fly, but it will be overly nose heavy, I guess when you balance it with the gear up, your committed to flying it that way, am I right? oh and yes the plane is epo foam, have had other planes from nitroplanes and all turned out to be good flyers, I also did swap out the servos, on flaps elev rud ailr, the retracts in the plane are servoless, and also has working gear doors and nav lights
"I guess when you balance it with the gear up, your committed to flying it that way, am I right?" No. You will need that gear. However, at speed with the gear up, your plane will fly well and with less trim.
You need to fly it and all this will become more clear.
