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October 3rd, 2006, 19:46
| #1 |
| Old Skool Join Date: Sep 2001 Location: San Diego, CA
Posts: 7,236
|  Aerodynamics Question for class I was absent during the day the professor gave these equations. How do I find the solution and what are the equations? An airplane has a published max gross weight of 4000 lbs, a published Vs of 68 kts, and a nL of 3.6. A) What is this airplane's max weight Va? Answer: 129 knots B) What is the Va at 3400 lbs? Answer: 118.9 knots C) What is the new stall speed when it pulls 2.4g's? Answer: 105.3 knots
__________________ Dash 8 FO "Time spent flying is not deducted from one's lifespan."  |
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October 3rd, 2006, 19:52
| #2 |
| Old Skool Join Date: Sep 2001 Location: San Diego, CA
Posts: 7,236
| Re: Aerodynamics Question for class I found out how to do the first problem: http://selair.selkirk.bc.ca/aerodyna...ft/Page12.html  But what about finding Va at 3400 lbs?
__________________ Dash 8 FO "Time spent flying is not deducted from one's lifespan." |
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October 3rd, 2006, 20:26
| #3 | |
| Old Skool Join Date: Sep 2006 Location: Memphis, TN
Posts: 2,016
| Re: Aerodynamics Question for class Quote:
= 129 * Sqrt(3400/4000) = 129 * .92 = 118.93 You could also derive it directly from the lift equation. | |
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October 3rd, 2006, 22:06
| #4 |
| Old Skool Join Date: Sep 2001 Location: San Diego, CA
Posts: 7,236
| Re: Aerodynamics Question for class Thank you very much! Problem solved 
__________________ Dash 8 FO "Time spent flying is not deducted from one's lifespan." |
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October 3rd, 2006, 23:30
| #5 |
| Old Skool  Join Date: Dec 2005 Location: Austin, TX / Grand Forks, ND
Posts: 1,886
   | Re: Aerodynamics Question for class quit cheating on your homework, jace 
__________________ CPL AMEL-I 175TT / 20 ME ...and a pulse. |
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October 4th, 2006, 00:04
| #6 | |
| Old Skool Join Date: Sep 2001 Location: San Diego, CA
Posts: 7,236
| Re: Aerodynamics Question for class Quote:
__________________ Dash 8 FO "Time spent flying is not deducted from one's lifespan." | |
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October 4th, 2006, 00:28
| #7 |
| Junior Member  Join Date: Apr 2006 Location: Atwater, CA
Posts: 155
| Re: Aerodynamics Question for class I'm glad nothing remotely similiar is on the written test |
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October 4th, 2006, 01:13
| #8 | |
| Old Skool Join Date: Sep 2001 Location: San Diego, CA
Posts: 7,236
| Re: Aerodynamics Question for class Quote:
__________________ Dash 8 FO "Time spent flying is not deducted from one's lifespan." | |
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October 4th, 2006, 01:21
| #9 |
| Old Skool  Join Date: Feb 2002 Location: Park City, UT
Posts: 12,000
 | Re: Aerodynamics Question for class It's not. You see it's not actually related to anything. At all. Ever. In fact stupid questions like this is one of the reasons I dropped flight. |
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October 4th, 2006, 01:25
| #10 | |
| Old Skool  Join Date: Dec 2002 Location: Utopia
Posts: 12,368
| Re: Aerodynamics Question for class Quote:
__________________  ------- I'm with Mike (Mikecweb)   | |
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October 4th, 2006, 02:49
| #11 |
| Senior Member  Join Date: Feb 2006 Location: (CBM) Columbus AFB, MS
Posts: 1,166
| Re: Aerodynamics Question for class Hey Jace, I noticed no one addressed the third question for you, so I figured I'd give you a hand with it. Set weight equal to lift and use the lift equation. W=L=1/2CL*S*rho*Vs^2. You already know Vs^2 and the max gross weight (4000lbs.), so solve for that whole mess in between (1/2 *CL*S*rho=.8650519). Then go back with that information and use a new weight (4000lbs *2.4 g's)= 9600lbs. Put that back into the lift equation and use the 1/2 CL S rho that you just solved for and then solve for the new Vs. 9600=.8650519Vs^2. Vs=Sqrt (9600/.8650519)=105.345 Oops. Edited the final formula.
__________________ Dude, what are you trying to do? Land the airplane or adjust the field elevation? Last edited by fish314; October 4th, 2006 at 02:50. Reason: Mistaken formula. |
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