Author Topic: Aerodynamics questions (Read 487 times)

Kirin · « **on:** March 23, 2005, 03:54:18 AM »

Greetings aces

yesterday I saw a documentary about some arctic flyers. It features C-130s that flew in and out the southpole.

On take-off they used some kind of RATO device. As they landed at the soutpole station the left some fuel on the ground to be able to lift off by own engine power again.

Now my question is why it's harder for those plane to get off the ground at cold temperatures (-50°C). Colder air should produce more lift shouldn't it? Do the engines generate less power at those temps? Enlighten me please!

Chairboy · « **Reply #1 on:** March 23, 2005, 09:42:33 AM »

Interesting, performance should be better...

What's the density altitude?

AKS\/\/ulfe · « **Reply #2 on:** March 23, 2005, 09:44:43 AM »

Maybe it was just a short runway?
-SW

RTR · « **Reply #3 on:** March 23, 2005, 09:47:11 AM »

I would suspect that the RATO was used because the runway was short. The Herc is a pretty big plane.

Just a thought.
RTR

OneWordAnswer · « **Reply #4 on:** March 23, 2005, 10:07:07 AM »

Quote

The ATO rockets are always attached to the aircraft before they go to unfamiliar areas. The bottles are about four feet in length and weigh 140 pounds each. Eight are needed for each takeoff. Hung at the back of the main landing gear fairings, the bottles equate to the power of an additional engine for about fifteen to twenty seconds. The flight engineer fires the bottles by pushing a button in the cockpit when the aircraft commander calls for them. Timing is critical. Firing the bottles too early doesn’t give the aircraft the boost needed to get the nose ski up and the aircraft airborne. The skis produce considerable drag.
http://www.firebirds.org/menu7/topbot1.htm

bunch · « **Reply #5 on:** March 23, 2005, 10:08:16 AM »

South pole is at a fairly high alt (over 2000m), due to the ice thickness...plus i would guess the runway is maybe on the soft side...wouldnt wager it is short, though, they have plenty of room & all day to lengthen it to whatever they need

Scootter · « **Reply #6 on:** March 23, 2005, 06:29:40 PM »

BIG diff. in long hard runway as oposed to short and SOFT one.

I think that would be the diff.

Cold should make it better correct but the runway conditions would make it much worse.

ThreeWordAnswer · « **Reply #7 on:** March 23, 2005, 06:41:53 PM »

Quote

Originally posted by OneWordAnswer

Not a OneWordAnswer.