Water explanation, please.....
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I'll explain the theory of C/G, and how this not works in Condor.
If you fly 180km/h in std class, you will need to push quite hard.
This means you have a lot of lift, and therefor drag, on your horizontal stabilizer.
If you put the center of gravity forward, you will need less lift on your stabilizer, as compared to the first situation, there is a little nose down moment by the weight.
Therefor you will have less drag, and you will perform better in that situation.
But then again, during slow flying it is completely opposite, you will have less drag when you have the C/G a bit to the tail.
Either way you have to find a compromis between thermalling and gliding performance.
But in condor (I was told) that C/G changes does nothing else but change the stick/trim range.
If you put the C/G back, you will be able to pull the stick further, back, and less forward.
And performance wise it will not matter in condor.
If you fly 180km/h in std class, you will need to push quite hard.
This means you have a lot of lift, and therefor drag, on your horizontal stabilizer.
If you put the center of gravity forward, you will need less lift on your stabilizer, as compared to the first situation, there is a little nose down moment by the weight.
Therefor you will have less drag, and you will perform better in that situation.
But then again, during slow flying it is completely opposite, you will have less drag when you have the C/G a bit to the tail.
Either way you have to find a compromis between thermalling and gliding performance.
But in condor (I was told) that C/G changes does nothing else but change the stick/trim range.
If you put the C/G back, you will be able to pull the stick further, back, and less forward.
And performance wise it will not matter in condor.
Think positive, flaps negative.
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I'm with you on this Fredrik. Even in the case of a trim tab, all the tab is doing is deflecting the control surface. My understanding of trim is that it is there for pilot comfort. Yet, in the other flight sim I use, IL-2, there is no shortage of advice to the tune that being "in trim" reduces drag.Fiddeflygare wrote:...i dont see how you would get less drag with the trim in neutral position? On a real life high performance glider and even most older gliders of glass/carbonfiber construction the trim only affects the stick as for example in my clubs LS8. This means that you would get the same drag having trimmed the aircraft to the speed you want as if you have the trim in neutral and push the stick forward in order to maintain your desired speed. Since you don´t have a trim rudder on the elevators.
How is a bungee or spring pushing the stick forward any different than the pilot pushing the stick forward? How is a trim tab deflecting a control surface any different than the pilot moving the stick and deflecting the same control surface?
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I guess I should have prefaced my remark by saying that my observations apply only to Condor and not to RL. As my RL experience is nil.
One of the things that made me adjust the CG was that in online play when I went to autopilot the plane would pitch significantly indicating to me that there was a disparity between the center of lift on the wings and the elevator. The lift surfaces were not working together. With the use of the CG slider my trim setting is now close to zero as opposed to greater than 50%. And now when I go on auto the plane makes only a small pitch movement, if any.
It also seemed obvious to me that if things are not working together there is a penalty. In this case increased drag (decreased lift, speed, etc.) and at my level of expertise a tenth of a meter in lift or speed may just get me to the finish.
One of the things that made me adjust the CG was that in online play when I went to autopilot the plane would pitch significantly indicating to me that there was a disparity between the center of lift on the wings and the elevator. The lift surfaces were not working together. With the use of the CG slider my trim setting is now close to zero as opposed to greater than 50%. And now when I go on auto the plane makes only a small pitch movement, if any.
It also seemed obvious to me that if things are not working together there is a penalty. In this case increased drag (decreased lift, speed, etc.) and at my level of expertise a tenth of a meter in lift or speed may just get me to the finish.
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Ok, you got me there.
But it took me a trip to the windtunnel and it's proffessors to convince me.
Knowing this I think, that in RL I have flown with a C/G too far behind.
As there were moments where dumping tailwater increased the performance tremendously.
But that also might have to do with the trimsprings, and mental aspects.
But it took me a trip to the windtunnel and it's proffessors to convince me.
Knowing this I think, that in RL I have flown with a C/G too far behind.
As there were moments where dumping tailwater increased the performance tremendously.
But that also might have to do with the trimsprings, and mental aspects.
Think positive, flaps negative.
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The University of North Dakota has some good software trainers that explain the effect of CG on lift. It is designed for powered flight but the basics of course transfer.
http://undaerospace.com/software_trainers.asp
You have to register but it is free. Find in the aerodynamics section the Weight/CG Effects trainer.
In commercial and charter operations, operators intentionally load to the aft limits because it is more efficient for the aircraft and they get better range and fuel efficiency. But it does reduce stability.
P.S. This is my first post in the forums. Hope it is helpful and productive.
http://undaerospace.com/software_trainers.asp
You have to register but it is free. Find in the aerodynamics section the Weight/CG Effects trainer.
In commercial and charter operations, operators intentionally load to the aft limits because it is more efficient for the aircraft and they get better range and fuel efficiency. But it does reduce stability.
P.S. This is my first post in the forums. Hope it is helpful and productive.
Joshua Clark
M41
N9223S
"Mumbles"
M41
N9223S
"Mumbles"
- Alpha Whisky
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I resemble that remarkOXO wrote:You should see some of the junk we have to read
Great link: http://www.dg-flugzeugbau.de/schwerpunkt-e.html
Don't know how well it's modelled in Condor but it explains the issues surrounding CofG in real life gliding.
- Alpha Whisky
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- Location: Scotland
That's odd, because the Condor manual says
You would think if it wasn't modelled at all, the manual would say "This setting has no influence on performance".C/G bias: Here you specify the relative position of your plane's center of gravity (C of G). The influence of this setting on performance is very small. The more important effect is glider handling.