Boeing B52 Stratofortress build update
- Thread starter Clement
- Start date
Grifflyer
WWII fanatic
That all depends on how you want to fly, do you want a slow floater or a faster scale flying model?
Grifflyer
WWII fanatic
Yep
Hello my good friends. Construction of my B52 will start very soon. I will be posting pictures all the way. Can someone very knowledgeable in aeronautics please tell me how wings generate lift. I have heard that the popular explanation about air on the top surface moving faster than air on the bottom surface is wrong. Please what is the correct theory about how wings generate lift?
Grifflyer
WWII fanatic
That one is most generally accepted as true, but you can also generate lift in the same way an elevator moves a tail, by deflecting air in a certain direction.
GMalatrasi
Active member
These are not mutually exclusive, both effects add up to generate lift.
buzzbomb
I know nothing!
Yep. My personal opinion? Don't overthink it. Correctly shaped and directed surfaces, when moved through the air generate lift. It's amazing to me that since the dawn of aviation, we still don't completely understand it. It is what it is, though.
Look at the Nutball. At it's purest it's just a surface that the motor and prop drag through the air. The simple act of dragging the surface along produces lift. If you stick your arm out the window of a moving car and hold your hand flat, then rotate your wrist? Does your hand move up and down because of positive pressure on the bottom, or lower pressure on the top?
You could sit with an aeronautical engineer, and he/she could no doubt go on at length about the exact lifting forces on a particular wing design, and if he or she were honest, there'd be a "but" here is the other school of thinking on that.
End of the day, we really don't know. But humanity builds planes and they fly.
I honestly know nothing about it. I was amazed to find out that neither does anybody else. All we have is theory. What we currently have is that it is either positive pressure beneath, or negative above. To my limited knowledge, that's pretty much it.
GMalatrasi
Active member
I can understand that understanding flight can be a bit confusing for anyone not formally schooled in the subject.
But there is very little mystery about how planes fly.
We understand all the basic principles of how air interacts with bodies and we have equations to mathematically model it. The issues come from the complexity of the equations when trying to solve for all the different variables at once. So we make assumptions to simplify the math. Or we use computers to solve the nore complex stuff (CFD).
Imagine Boeing spending millions of dollars and thousands of engineering hours designing a wing and in the end it’s all a guess...?
I just want to make sure we are spreading good information.
Jeez, it's really simple. Didn’t they teach you anything at school? I guess you can understand how the air moves around the wing. You only have to apply a bit of smoke to see it. OK, so you can see where it changes direction. Now you have to look on a smaller scale to see what effect that has. You have to go right down to a quantum level.
Whengo the air changes direction, it upsets the spin and movement of some of the charmed quarks inside the D mesons and charmed Sigma mesons. This causes some of them to jump out of our universe into the quantum plane where they're affected by the 8/9ths of the gravity that's missing from our universe, so that when they jump back they have an affect on the gravitational field around them, which according to Flemmings right hand rule is at 90 deg to the direction of change in velocity they were travelling before and after the change in direction. The net affect is that gravity in our universe in the vicinity of the wing, where the air changes direction, is distorted in the direction at right angles to the mean direction that the air travelled before and after it changed direction. This affect on gravity is equivalent to a distortion of the space-time continuum that makes the wing fall in that direction. To get the overall direction, you have to integrate the direction change of every particle of the air, which is why the ones moving turbulently create drag because the gravity well will be in the direction behind the drag, i.e. the wing tries to fall backwards when the air is moving backwards turbulently.
To summarise, when the air makes a change in direction as it goes round the wing from say 180 deg to 190 deg, the gravity well will pull the wing at an an angle of approximately 95 deg, which is mainly upwards and a little bit backwards. We try and explain it as lift and drag forces, but actually, the wing is falling in that direction into the distorted space due to its own mass. It's the same thing as what sticks you to the ground. You're effectively sliding down the gradient in the space-time continuum. You have Einstein to thank for that.
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I would like my B52 to fly real slow. From my research I saw that highly undercambered airfoils, large wing area and low weight are the 3 key factors. Please could someone post a picture of an undercambered airfoil with dimensions I can use. Proposed wing span is 60cm by the way.
Also please what angle of attack should I use for the wing?
Also please what angle of attack should I use for the wing?
I don't think that'll work. What I'd do is go for a fat symmetrical wing section so that you can fly with a high angle of attack when you want, but It'll still fly normally when level. Under-cambered wings are a bit weird to fly and not so easy to control. You can also slow down your plane with flaps, but you wouldn't want to fly it around for two long with them down.
I'd like to know what Flemming was doing with his left foot when he came up with his right hand rule
Agree that the undercamber approach may complicate the flying characteristics. A fat symmetrical foil would be nice. I think some of this depends on how you intend to build. The FT Edge symmetrical foil it put together pretty well and you might be able to adapt that approach to your design. Beyond that, a simple FT flat bottomed style airfoil would be my next suggestion - easy to build - flys pretty well.
DamoRC
Thank you guys. Damo RC you mentioned a simple flat bottom airfoil would be nice. Please could you post a link so I can see the exact dimensions. Assuming the chord length is 10cm, what should the thickness be please. Should i incorporate an angle of attack to the wing or should it be parallel to the fuselage. If you are in support of incorporating an angle of attack, what would be an appropriate angle of attack for a plane this size.Proposed wingspan is 60cm
Grifflyer
WWII fanatic
Something like 1.7cm - 2cm should work well. If you want zero angle of attack on the wing you would mount it parallel to the horizontal stabilizer not the fuse. If you want to have some angle of attack I wouldn't go over 2 degrees. Something like 1-1.5 degrees should work.
