h a l f b a k e r y
Please listen carefully, as our opinions have changed.

meta:

account: browse anonymously, or get an account and write.

 user: pass:
register,

Save all that unnecessary climbing and descending.
 (+7) [vote for, against]

I recently took a short haul jet flight, a mere 44 minutes of low cost intercity travel that would have been a pleasant rail journey were it not for the inconvenient but necessary Irish sea. The flight profile seemed faintly ridiculous. A quick investigation on FR24 reveals that after the initial climb, a phase that varies little between routes, the flight had three distinct phases. Phase 1: 7 mins of climbing from 4000ft to 18,000ft averaging 265kn. Phase 2: a 7 minutes gentle descent from 18,000ft to 15,600ft at 308.5kn. Phase 3: an 8 minute 15,600 to 3500ft descent at 258kn. Before the proper and unavoidable approach.

Now, that plane was either climbing or descending, the poor cabin crew had to push the drinks uphill from the back, then uphill from the front on the way back. It was silly. I have done some calculations and just because of the ascent and descent angles that plane flew 0.17 nautical miles further than it had to*. I'm not sure why they bothered going all the way to 18,000ft when they had to immediately had to start descending. It costs fuel and or speed to gain altitude, you put the aircraft through more pressurization cycles and make the poor cabin crew work uphill.

I assume this is because the aircraft is designed to be efficient at >30,000ft and has a fancy wing to go with it. How about an aircraft designed for a quick low altitude dash across the sea? A flight profile after take off would consist largely of acceleration and climb to say, 3000ft. There it stays, maintaining a respectable oooh, 420kn, until it"s time for final approach.

You'll need a new airframe for this kind of flying, the wings of a traditional airliner are all wrong. Instead our model will be TSR2. Low wing area/weight giving a relatively large wing loading and minimal drag in low altitude thick air. The civilian passenger aircraft wont have the power surplus for high altitude flight, but that doesn't matter, it'll never need to. These restrictions mean we can simplify the aircraft considerably. If it can't get above 10,000ft we can start throwing stuff out. Pressurization associated airframe design, pressure management equipment, fancy heating systems and so on. Small wings are lighter and tougher, they take up less space at the airport meaning you can park close and the jet way** will be much shorter. Now you flew faster, landed faster***, parked closer and as such you're in front of those morons on the 737 in the immigration line... has to be 15 mins right there.

*I admit, that was quite small.. the number for a 30min cruise- climb is not insignificant, however.

** 1 min extra walking here was 8 miles in the air.

*** landing speed could be a bit scary, aircraft should also be optimized for quick taxiing... maybe a folding fin so it can sneak under a 777 wing and steal a better baggage carousel.

 — bs0u0155, Nov 03 2016

Antonov AN-72 https://en.wikipedi.../wiki/Antonov_An-72
A good starting point ? [8th of 7, Nov 03 2016]

TSR-2 http://www.gknapman...xr219-in-flight.jpg
[bs0u0155, Nov 04 2016]

Hunting H.126 https://en.wikipedi.../wiki/Hunting_H.126
"... built by Hunting Aircraft in order to test the concept of blown flaps ..." [8th of 7, Nov 16 2016]

 — MaxwellBuchanan, Nov 03 2016

 // necessary //

 Sp. "essential"

 // I'm not sure why they bothered going all the way to 18,000ft when they had to immediately had to start descending. //

 Could just be fickle ATC ...

 3000' AMSL means you're in uncontrolled airspace; there could be anything hiding behind (or in) that cumulus ...

What about the AN-72 as a starting point ? A high-loaded wing doesn't go well with STOL so the short-field cability would need to be sacrificed, but would give higher cruising speeds.
 — 8th of 7, Nov 03 2016

Also beneficial to Chinese short distance between cities flights.
 — beanangel, Nov 03 2016

High speed trains would be more cost effective in the long term in that application- once the huge capital cost of the track has been paid.
 — 8th of 7, Nov 03 2016

Given that the Chinese are so small, why don't they just build their cities closer together?
 — MaxwellBuchanan, Nov 03 2016

 My TSR2 inspired anhedral wingtips will harness extra ground effect for take off. However, the Soviet naval yard construction techniques may be prohibitively expensive to recreate. I will, instead, have to rely on the disappointingly reliable and lightweight methods so prevalent in the current aviation industry. Perhaps as a tribute, I could ignore conspicuous productivity/laziness and instead reward those who agree with me, special privileges for those who come up with creative new ways in which I was right.

I think a high wing and high engine mounting may also be carried over. These allow shorter undercarriages, possibly short enough that a full length platform, rather than stairs/jet way, would be sufficient. In further tribute to British transport ingenuity, each row could have its own door opened by the passengers themselves. As a result parallel, rather than serial, entry and exit may be achieved.
 — bs0u0155, Nov 03 2016

 //there could be anything hiding behind (or in) that cumulus ...//

A brief mention of this fact during the pilot's PA would perk up the most jaded of passengers. Adrenaline is lighter, more effective and freer than coffee. Throw out the coffee and all associated gubbins at the back.
 — bs0u0155, Nov 03 2016

At LCY there's a lot of Avro RJ85 in and out, typically there'll always be from about three to seven of them in at any one time, with many more in the air to and from. It is an aircraft with a fascinating history, starting life as the BAe 146.
 — Ian Tindale, Nov 03 2016

 For short journeys, how about having a very long arm (half as long as the distance between starting and ending points) mounted on a pivot at the midway point?

 An aircraft bolted to the end of this arm would have to provide enough power to lift the arm (and itself) to the vertical position; but this energy could be recovered by a suitable generator at the base of the pivot, as the plane descended on the other side.

As a bonus, if a plane ever went missing, the search could be confined to a circle of arms-length radius around the pivot point.
 — MaxwellBuchanan, Nov 03 2016

Or have the aircraft mounted on rails. It could even go through tunnels underground, that way.
 — Ian Tindale, Nov 03 2016

That's sheer insanity, [Ian]. You'll have wingless planes that float next.
 — MaxwellBuchanan, Nov 03 2016

It seems to me that with a bit of fore planning, it would be simpler to store the drinks forward so they are pushing the trolleys downhill both ways.
 — AusCan531, Nov 03 2016

Better yet, simply plumb drinks to each seat, and equip said seat with a tap.
 — MaxwellBuchanan, Nov 03 2016

 // reward those who agree with me, special privileges for those who come up with creative new ways in which I was right //

 In terms of management science, that's just sheer undiluted genius. We have no doubt that your meteoric* rise to fame and fortune is even now beginning.

 In ages to come, there will be statues of you in every town, images of you in every home and workplace, your name will be spoken only in hushed whispers by the anointed priesthood, and the bulk of the population will worship you as a God.

 // You'll have wingless planes that float next. //

 Hahaha ... for an extra laugh, why not make them of thick steel plates, welded together ?

*Spectacular, fascinating, and ending in a huge explosion on the edge of the atmosphere, after which little charred fragments rain down over a wide area.
 — 8th of 7, Nov 03 2016

ahem, continuing to think the idea has merit, I will casually include Chinese searchbait so the Chinese will discover this idea as well as the halfbakery. Short range improved passenger airplane with minimal defense applications is &#26368;&#23567; &#30340;&#22269; &#38450;&#24212; &#29992;&#30701; &#33539;&#22260; &#25552; &#39640; &#38081;&#36335; &#23458;&#36816; &#39134;&#26426;, or so Bing tells me.
 — beanangel, Nov 03 2016

 // High speed trains / cost of the track //

Bah, track?? Get them fast enough and skip them across the water like pebbles. This alleged Irish Sea can't be that wide, shirley?
 — BunsenHoneydew, Nov 03 2016

 // Get them fast enough and skip them across the water like pebbles. //

That would be a great way of getting pedestrians across rivers, certainly. A casing similar to Barnes Wallis's "Upkeep" bouncing mine could contain several passengers, if they were forced in. And they would undoubtably have to be forced in ...
 — 8th of 7, Nov 04 2016

It's actually not the wings, it's the engines. Going up to 18,000ft only briefly does save fuel and the planned cruising altitude is calculated to take air density, temperature, and winds aloft into account for the most efficient cruise. If you do want a more efficient plane for short, low altitude hops that does exist. It's called a Q400. Passengers don't like propellers for some reason though.
 — DIYMatt, Nov 09 2016

Could the high altitude route also be a risk mitigation strategy? In case of engine failure, higher altitude results in a higher probability of gliding to land. I know these things are supposed to fly on one engine, but every now and again you can loose both. It seems like pilots and regulators like to add safety margin wherever they can if it doesn't add too much to the cost.
 — scad mientist, Nov 09 2016

 "Height is money in the bank"

 The five most useless things for a pilot are:

 Sky above you Fuel in the bowser Runway behind you Maps in your car Airspeed you don't have

 // Passengers don't like propellers for some reason though. //

Because they're stupid ?
 — 8th of 7, Nov 09 2016

An underground tunnel to the Irish? You British really are suicidal, aren't you? One would think the Chunnel to France would have been bad enough.
 — RayfordSteele, Nov 10 2016

Ah, but there's a Secret Plan to link the two English ends without telling the french (the Irish won't notice).
 — 8th of 7, Nov 10 2016

 //Q400. Passengers don't like propellers for some reason though.//

 350knt cruising speed? Pfft. Massive ungainly wobbly wings, they just add unnecessary stuff, engineers get carried away! Someone suggests longer heavier wing, then the ailerons are further away, you need longer hydraulics with more fluid, more weight. Then you need more lift. So you add flaps and slats and all the associated jackscrews and hydraulics, more weight! Now you need even more wing. That gives you more drag, so you need bigger engines which weigh more and use more fuel, which weighs more. Look at what happened to the B2! That was supposed to be an airliner until the engineers got carried away and had to ditch the whole fuselage and empennage to save weight.

No no. Short stubby lightweight wings, make the ailerons fully independent flaperons doing double duty, save weight again. The real genius is the speed. You can have Q400 style 700sq ft of wing and fly at 300kn or 300sq ft of wing at 600kn. You get there quicker, you even take off faster, the pilot has less distance to cover on the pre-flight walkaround. While it might not be true, it is a fact that 32% of B52 flights have to be cancelled due to pilot navigation errors during the walkaround, resulting in confused aviators walking on compass bearings babbling incoherently about fabled engine nacelles just beyond the horizon.
 — bs0u0155, Nov 11 2016

 // You get there quicker, you even take off faster //

 ... and presumably land faster, too ?

 You aren't advocating the likes of the MD-82, are you ? Little thin wings, long narrow fuselage - basically a passenger version of the Starfighter (It didn't get the nickname "flying coffin" by chance).

 Even with flaperons along the whole trailing edge, and slats or droops, what's the margin between stall speed and landing speed ? If it isn't generous, thou shalt be Banished to the Outer Darkness, or Basingstoke (whichever is more bleak, desolate and soul-destroying, so probably Basingstoke).

 // due to pilot navigation errors during the walkaround //

 They give them those electric golf buggy things now, with a GPS strapped to the dash.

Doesn't help much, tho.
 — 8th of 7, Nov 11 2016

 // So you add flaps and slats and all the associated jackscrews and hydraulics, more weight! //

 Say hello to this little chap, on display at RAF Cosford ...