Sir, do you know if there is a standard equation for a given speed/altitude/air density to figure the speed of heat where aircraft surface temperature changes from cold to hot? iirc it was about 500knots at a nominal altitude of 40,000'
thx
Posted on 09/14/2014 8:19:53 PM PDT by rey
I home school a young girl. In years past, we have gone to the local air show and done such things as measure the tops and bottom of wings and rotos and figure the ratio or difference between the area of the top of the wing versus the bottom and estimated which wings had more lift than others. We measure how much area the wheels occupied on the ground and consulted with the crew chief what the tire pressure was and calculated the weight of the plane.
In years past we were able to see F18s form a vapor cone around the plane and discussed how pressure can squeeze the moisture out of the air to give us this effect. There won't be any military jets this year, but there will be an Osprey, P38, Corsair from WWII, T38, the helicopter pilot from Red Bull who flips and rolls a helicopter.
Before going we review some physics books and discuss what properties of physics and laws of motion apply. We do a similar thing at the fair; she cannot go on any ride if she cannot name at least two laws of motion that apply. When we watch the planes or fair rides we point out what laws of motion we are witnessing.
My question is this; What other math problems could we review on the static displays or any other happening at the air show? She is 10 and is well into algebra. We have done a little trig when trying to figure target info for various firearms or catapults. WE have done very little calculus, but if someone can outline something well enough we can definitely figure it out.
We are open to any aspect of aeronautics, whether is is mathematics, chemistry, physics, scientific.
There are some very sharp people on this site and wish to thank everyone in advance for their help.
How much of a jet engine’s thrust is needed to overcome drag.
Sir, do you know if there is a standard equation for a given speed/altitude/air density to figure the speed of heat where aircraft surface temperature changes from cold to hot? iirc it was about 500knots at a nominal altitude of 40,000'
thx
I like that. For a little variety, have her sometimes do a Conservation of Energy trace (don't worry, it just sounds tough, it's easy).
First recall that energy is the ability to do work.
Conservation of Energy: Energy cannot be created or destroyed, just transferred.
So here's an energy trace example. A plane taxing down a runway has kinetic energy (energy of motion). That energy has to come from somewhere, and go somewhere.
Where did the plane's kinetic energy come from? It came from gasoline in the plane's fuel tanks. Where did the gasoline's energy come from? From the ancient plants that formed oil. Where did those plants get that energy? From the sun. Where the sun got its energy is a religious question!
Now suppose the plane stops. Where did the plane's kinetic energy go? It has to go somewhere! The plane's energy was converted into heat by friction. The plane's tires get hot, and eventually the whole universe will get just a tiny bit warmer.
You can do such energy traces with a person walking, the energy stored in a hamburger, the energy stored in a brick at the top of a building, etc. I think it's quite fascinating.
If you have any questions about this, feel free to FRmail me. The first hundred questions will be free!
There is no cold. Only heat variance.
After that, I could not help you.
Can’t come up with a specific equation, but the effect of engine torque on controlling the aircraft — the Corsair had a lot of torque to overcome.
With the P-38, the effect of dual props turning in the same or different directions.
If you look around, you should be able to find some things that are at least interesting from a historical education perspective, but could give some math or physics education.
Check out Aerodynamics for Students. Looks like there's a fair amount of material that is suitable for algebraic understanding. I'm sure you'll have her in to DiffEq real soon!
true, cold by definition is simply the absence of heat, but if you touched the surface of a plane doing say 400K at 40000' it would feel cold, where the skin of a Blackbird reaches 1000+ i thought there might be a standard formula to determine the crossing point, thx
I wish I could help.
Very inspirational. Great post!
Lots of other math can be demonstrated with a flight computer, which is essentially a circular slide rule. The ASA A6B paper flight computers are CAD $13.95 and the metal version is $32.95 here.
interesting
From tire pressure and flattening try to estimate total weight and center of gravity. Estimate fuel tank capacities and cg locations. Work out trimming needs and fuel management.
much appreciated, thx again...
I think he crossed the wake turbulence of a leading aircraft in a turn Good thread bump.
This is a contradiction in terms, since "a plank with an angle of attack of about 55" is no other thing than an airfoil, however inefficient.
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