Calculate the density at which the available thrust is equal to the minimum drag

Click For Summary
SUMMARY

The discussion focuses on calculating the density at which the available thrust of a jet-propelled airplane equals the minimum drag during full fuel load conditions. Key parameters include a wing area (S) of 29.5 m², a weight (W) of 88,000 N, a drag coefficient (CD,0) of 0.02, and a thrust coefficient (CT) of 1.7 x 10^-4. The minimum drag (Dmin) is calculated to be 5,221 N using the formula Dmin = 2((CD,0*k)^0.5)*W. The challenge lies in determining the density without knowing the velocity, which is essential for relating drag to density.

PREREQUISITES
  • Understanding of aerodynamics principles, specifically thrust and drag relationships.
  • Familiarity with the drag equation and coefficients (CD,0 and k).
  • Basic knowledge of jet propulsion mechanics and thrust calculations.
  • Ability to manipulate equations involving density and velocity in fluid dynamics.
NEXT STEPS
  • Research the relationship between thrust, drag, and density in jet propulsion systems.
  • Learn how to derive velocity from thrust and drag equations in aerodynamics.
  • Explore the effects of altitude on thrust and drag coefficients for jet engines.
  • Investigate computational fluid dynamics (CFD) tools for simulating thrust and drag interactions.
USEFUL FOR

Aerospace engineers, aerodynamics researchers, and students studying jet propulsion and fluid dynamics will benefit from this discussion.

liam1992
Messages
19
Reaction score
0
Calculate the density at which the available thrust of a jet propelled aeroplane is equal to the minimum drag for the full fuel load case. Use the simplest assumption for the variation of engine thrust with density.

Wing area, S = 29.5
Weight, W = 88000
CD,0 = 0.02
k = 0.044
Max thrust (at sea level) = 16000N
CT = 1.7*10^-4

I use the formula Dmin = 2((CD,0*k)^0.5)*W = 5221N

The problem I have is that I can't work out the density without the velocity but there is no way to relate velocity to drag without density. Where do I go from here?
 
Physics news on Phys.org
If you care to revise your posting, supplying the units and explaining what each of the three co-efficients is, I'll take a look at your problem.
 

Similar threads

Calculating Constant Thrust for Jet-Powered Drag Car in Vehicle Dynamics Class
  • · Replies 4 ·
Replies
4
Views
3K
Calculating Lift-Drag Ratio of a Wing Under Flight Conditions
  • · Replies 4 ·
Replies
4
Views
6K
Calculating Aircraft Physics for a Simulation Game
  • · Replies 1 ·
Replies
1
Views
3K