How would you determine the Lift(thrust) force of a Helicopter in hover

fujifilm6502002

I know the lift force equation is .5*rho*V^2*Area*Coefficient. But I was wondering in the real world how would you measure the lift force? I hope they don't just plug the values for the equations.

Danger

The easiest way is to weigh the helicopter. If it's hovering, the lift force equals the weight.

fujifilm6502002

I was wondering like if you are building your own helicopter what would someone use to test the amount of thrust produced by the rotor?

eaboujaoudeh

i wonder if bernouilli's equation can be put to use in this case. i know that it can be used when there is wind driving a wind turbine. it should work here

fujifilm6502002

I guess you can use Bernoulli to calculate the change in pressure helicopter.

eaboujaoudeh

i think u can find the maximum power yield by zeroing the velocity at the exit

haa72

yeah we can find the maximum power yield by zeroing the velocity at the exit

if smbody interested , i caN upload a book on the aerodynamic of the helicopter.
tel me if interested
regards

fujifilm6502002

That would be great.
Thanks

haa72

I will try tmrow , i willl send u a link on rapidshare or mhid.net;
ur welcome and hope that will be helpful

eaboujaoudeh

definitely interested in that:)

FredGarvin

You could do this simply with a spring scale and something to constrain the rotor group to the scale and something to drive it. It is even easier if you have a strain gauge based force transducer because then there would be no axial movement due to the thrust.

In regards to the original question, the airfoils and rotors are well known throughout the flight envelope from wind tunnel testing. The calculations involve effects of trailing blades, etc... Of course, the calculations are always compared to actual testing.

russ_watters

To test it, you mount it on a test rig and measure the forces.

P.Ramesh

scale down models and wind tunnels are to measure the force.

haa72

this si the link uploaded in the rapidshare

Hope that it is helpful

Attached Files

Seddon_J._-_Basic_Helicopter_Aerodynamics__BSP_Prof._Books_1990_.pdf (4.9 KB, 216 views)

haa72

another book

Attached Files

US_Navy_-_Introduction_to_Helicopter_Aerodynamics_Workbook_CNATRA_P-401__US_Navy_2000_.pdf (4.9 KB, 104 views)

haa72

http://rapidshare.de/files/22495932/...Navy_2000_.pdf

haa72

http://rapidshare.de/files/22495355/...ooks_1990_.pdf