Microlighters

How does one calculate the max climb limit of your wing, not the current max performance you get, but the wing limitations?

I've read of some trikers getting 1800fpm@55mph climb and wondered about structural failure etc.

DieselFan wrote:How does one calculate the max climb limit of your wing, not the current max performance you get, but the wing limitations?

I've read of some trikers getting 1800fpm@55mph climb and wondered about structural failure etc.

Hi DF,

As long as you don't exceed VNE or max G (+) you can climb at any rate without fear of structural failure.

Fly Safe,
R

A constant climb of 1800fpm, would probably be experienced during some form of turbulance or lift. If the climb remains smooth and constant then the trike would not experience any ill effects as these will be close to or at 1 g

However sudden changes in direction up or down will result in increased g-forces on the trike.
A trike can typically handle up to a +6g. This means your wing could be able to carry up to 6 X 450kg (whatever the max all up weight of your trike is and the max g-rating) = 2700kg. Most humans (not trained aerobatic and figher pilots) will begin to black out at about 5 G's. This is when an 80kg man has the weight of a 320kg gorilla sitting on his chest. Your body will feel the ill effects of the force way before your trike does.

I was kinda trying to work out the amount of G's experienced.

Lets take an arb number 2000fpm or 11m/s would be more than 1g? Lets say it is constant and even at 4000fpm the wing is working very hard to provide such huge amounts of lift?

Is it as simple as saying this
Airspeed = 55mph or 25m/s
If lift is 2000fpm or 11m/s
Forward speed would be 25-11 = 14m/s
Now using goalseek...the crossover point would be 2200fpm, where you climb more than you go forward.

Is it not that VNE is based on forces hitting the frontal area of the wing and not the "lifting" portion, eg lets say VNE 60mph, decrease angle of attack to produce less lift do 70 and wings collapse backwards. I suppose what I'm looking for is a lifting or vertical VNE number, even if it's not in mph then atleast amount of G's.

I read of a hanglider who exceeded the vertical component in a thermal and had an instructor mention he literally thought aliens were beeming him up as the earth shrank so fast (Botswana Pans)

Sorry for waffling.

Hi DieselFan,

there is no relation between rate of climb, and G force. If you are at a constant rate of climb, even if it is 10 000 feet per minute, you will only feel 1G. If you jump out of an aeroplane and reach constant velocity, ie your rate of descent is constant, you feel 1G. To have a change in G-force, you need acceleration, ie change in direction or speed.

In calm weather, ie no turbulance, or thermals, the rate of climb is the excess power your motor produces over the drag at a given speed. This excess power is then used to overcome gravity, and you gain altitude. If you now shut down your engine, and glide at the same speed, gravity will provide the "power" to move you forward, ie you will lose altitude. Your wing will still provide the same lift. In calm air, at a constant speed your wing will not feel the difference between a descent or a climb. All happens at 1G.
If you fly a constant speed, the direction that the air hits the wing remains the same, ie your angle of attack remains the same, regardless if you climb or descent.

Regards,
Arnulf

Arnulf wrote:There is no relation between rate of climb and G force.

If there was, then getting a man to the moon would be out of the question.

Regards
John [who prefers 1G] CIB

Thanks guys, I realised today that asking questions late at night isn't always a good thing.

Standard highschool science
Acceleration = G's

Which was actually what I was meant to ask in first place, the acceleration limit of a wing. Ofcourse Newton helped out here.