Naked Science Forum
General Science => Question of the Week => Topic started by: katieHaylor on 12/11/2018 15:21:23
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Daniel asks:
Why are propeller planes and not jet engines (with the forward-facing fan blades), used to investigate hurricanes? Are propeller engines safer in high stress situations?
What do you think?
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Jet aircraft have been used to fly into hurricanes in the past. The Lockheed U-2 and Boeing WB-47 are two examples. Even today, the Gulfstream IV-SP (G-IV) is used. My best guess for the seeming preference for propeller-driven aircraft is because of their superior fuel efficiency.
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Could a propeller plane, with its lower speed, be more maneuverable for flying into the eye of a hurricane?
I guess you would want to ensure that the hurricane wind speed does not exceed the maximum speed of the propeller plane/ (...or else you fly downwind instead of upwind!)
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I guess you would want to ensure that the hurricane wind speed does not exceed the maximum speed of the propeller plane/ (...or else you fly downwind instead of upwind!)
Interesting point - I'd never considered that; it's certainly possible with a small plane I would think to fly "backwards" in a hurricane.
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Wind speed is unimportant once you are airborne - a plane flies relative to its ambient air, not the ground.
Choice of plane depends on the precise mission. If you want to explore a small part of the sky, a low stall speed (and a fairly benign stall characteristic) will give you a tighter turn radius: most small prop planes stall at 60 kt or less, but bizjets tend to drop out of the sky at 80 or more, and can be a handful to recover from a spin. If you are interested in turbulence, you'll want a ship with good aerobatic capability (+10 -5 g at least) which is not what bizjets do best. At low levels, you won't expect much icing in a hurricane, and props are more economical than jets below 10,000 ft. Some prop aircraft are known to be good ice carriers at higher altitude but for routine exploration above 15,000 ft a turboprop or pure jet comes into its own.
Piston engines are generally more tolerant of short flights with widely varying power demand from loiter via "75% cruise" to "120% combat" and in the event of an encounter with hail or flying debris, a propeller is a lot cheaper to repair than a jet fan. Jets really don't like starting, stopping, or loitering: think retrievers and greyhounds!.
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I guess you would want to ensure that the hurricane wind speed does not exceed the maximum speed of the propeller plane/ (...or else you fly downwind instead of upwind!)
Interesting point - I'd never considered that; it's certainly possible with a small plane I would think to fly "backwards" in a hurricane.
I suspect that from at least some points of view it is almost inevitable to fly backwards in a hurricane.
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But not a Hurricane. Though more tolerant of bullet damage than a Spitfire, it doesn't take well to tailsliding or any reverse flow over the control surfaces.
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I once exceeded the speed of sound in a commercial airliner (as measured by ground speed).
They took a longer path around an intense low-pressure system, but got to the destination ahead of schedule (without ripping off the wings :) ) by "going with the flow".
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I landed a Beechcraft Musketeer (stall speed about 60 MPH) at a small airport in FL with a headwind straight down the runway at a constant speed of about 60 MPH.
no problem landing, but then proceeding to the taxi way was interesting...she insisted on wanting to fly again as I crept forward with an additional 5-10 MPH just to get there.
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I asked the captain and he said https://eu.usatoday.com/story/travel/columnist/cox/2016/05/29/turboprop-propeller-plane/85045552/ "Answer: The turboprops are more tolerant of hail than the jets. Airplanes that penetrate thunderstorms have an increased chance of encountering hail. Additionally, the two types of airplanes used, the P-3 and the C-130, are especially rugged."
I guess the same applies in a Hurricane, A prop driven plane is slower than a jet engine, and if a plane is flying slower then it will also suffer less strain, in adverse weather conditions :) flying through hail, fishes, buses, trees, cows etc, that one might find in a hurricane after being sucked up. :)