With the demise of Boeing's flying coffins (the 737 MAX) there is no reason why they shouldn't be offered as non-flying structures to anyone with a better idea than parking them in yet another desert boneyard (see link).
So, my idea is to make them available for inventive reconfigurations in the form of a global competition.
My own initial offering is to convert one into that of a bi-plane. The entire process could serve as an apprenticeship for the CAD designers, engineers and technicians needed to add another set of wings to an existing 737 MAX. The ability to actually fly would be a bonus, especially given that in its present form the 737 is as viable as a giant breeze block with wings.
Another version would see the 737 with its wings and tail clipped to become a luxury "stumpy bus". Its diminished form would still be viable as a road transport vehicle, able to make long highway journeys, provided there were no low level bridges, and the engines had been converted to run on a non-polluting power system.
My final idea is for the fuselages of the planes to be cut up into cross sections for purchase as extreme home cinemas. Each cross section would contain a full row of seats spanning the width of the plane. A bulkhead with an access door. A toilet and galley/cooking area, along with high def wide screen projection and surround sound would complete the facilities on offer.
Now all I need do is to convince Boeing that this is a worthwhile project.-- xenzag, Feb 23 2020 Chesley Sullenberger https://en.wikipedi...hesley_SullenbergerProstrate yourself, bang your forehead on the floor and declaim "We are not worthy !" [8th of 7, Feb 23 2020] boneyard https://www.flexpor...anes-salvage-value/.... to calm down DrBob [xenzag, Feb 23 2020] Actually, what you want is a triplane, but with the three sets of wings oriented orthogonally. In that way, the plane will be capable of remaining airborne regardless of the commands sent by the computer.-- MaxwellBuchanan, Feb 23 2020 "Land, land, land damit! I keep telling it to land but it just won't go down."-- xenzag, Feb 23 2020 As [Max] points out, there's nothing much wrong with the airframe (apart from an over-reliance on fragile composites, which is true of most current civil aircraft) - it's the die-by-wire flight control system that is (literally) the killer.
Replacing the electronics with good old fashioned pushrods, hydraulics and cables would fix the problem, at the expense of reduced payload, range, passenger capacity, or any combination of the preceding. The older systems are heavier.
Oh, and you actually have to train the pilots to fly, instead of giving them a game console to play on. That's a huge part of the problem. Many commercial pilots lack competency in stick-and-rudder skills and are bewildered when the automation betrays them. There aren't enough Sullys to go round ...-- 8th of 7, Feb 23 2020 link? What link? //it just won't go down// As it is a Sunday, I shall heroically resist the urge to make any outdated, smutty comments involving theologians & thespians.-- DrBob, Feb 23 2020 We said that already ...
Altho bigger engines are usually a good thing. Not always, but usually.
It's not that the problem "was" the FCS, the problem "is" the FCS; and not just in the MAX. Most civil aircraft built in the last 20 years (Boeing, Airbus, etc.) are critically compromised; it's just that most punters aren't aware of it yet, and the aviation industry - including the regulators - are trying very hard to keep the facts quiet.
The big winners are, bizarrely, Sukhoi, who have their own home grown systems. Simpler, cruder, more demanding on piloting skills ... but carved from solid, not just cribbed from the less desirable bits of the MS Flight Sim graphics engine ...-- 8th of 7, Feb 23 2020 // if pilots knew when to override it //
That's the killer. Too many pilots lack a sense of the "feel" of what the plane's doing.
It's perfectly reasonable to put an aircraft in straight and level flight, then tweak the throttles to adjust pitch and yaw; private pilots do it all the time, because it's part of the fun; like seeing how fast you can put a car into a corner before it starts to unstick a bit. It's how the crew managed to get their crippled DC-10 into Sioux City with no hydraulics. But such familiarization is strongly discouraged on civil airliners, even though it's normal, harmless and indeed very useful; military pilots do it all the time, because they're expected to be able to fly and land with important bits damaged or shot off ... situations no autopilot can ever cope with.
Oh, they practice asymmetric flight, and engine-out landings in the simulator, but they don't get to "play" with the real aircraft, which is a tragic mistake. Put a jet-jockey in the right hand seat of a puddle jumper, say "You have control", and watch the little beads of sweat on the forehead pop out ...
If you want to let them try a landing, best to carry a big can of air freshener. And put a disposable cover on their seat. Sphincter control not guaranteed.-- 8th of 7, Feb 23 2020 You're missing the point here: These planes are defunct. It doesn't matter what Boeing does, no one will fly on them again, so they should be scrapped and repurposed. The final nail in these flying coffins will be when the travel insurance companies refuse cover for anyone travelling on them.-- xenzag, Feb 23 2020 Except that can't happen. The investment in planes and associated infrastructure must run into the trillions. The planes have a fault; it can be identified and, once that's done, they will be allowed to fly again.
Even before any fixes, I'm sure the odds of a 737 Max having a safe journey were better than the odds of a bus having a safe journey.-- MaxwellBuchanan, Feb 23 2020 No one will fly in them. It's simple. Regardless of how much money has been invested in them, they will forever now be known as Boeing's flying coffins, so they'd be well advised to get on board with my idea and cut their losses. I am doing my best to help them out of the big hole they have dug for themselves here.-- xenzag, Feb 23 2020 Well, once they solve the square-window problem with the Comet, it went on to be fairly successful. And that was despite the fact that the roof had come off several times.
People want to get from A to B cheaply and quickly, and they don't really want to pay for safety.-- MaxwellBuchanan, Feb 23 2020 If no one wants to fly in these aeroplanes they could be refitted as cargo planes and flown by remote control.-- hippo, Feb 23 2020 ... into tall buildings...-- 8th of 7, Feb 23 2020 Well, if I ended up flying on a 737 Max, I don't think it would bother me particularly. Of course that may say more about me than about the plane.-- MaxwellBuchanan, Feb 23 2020 Ah yes, but if you had a choice, and there was no insurance for the winged coffin, or if you were buying a ticket for someone you cared about. The brand is now toxic. Watch as they renamed it and go through all sorts of laughable nonsense to convince people that it's somehow safe to fly in something that's liable to decide to fly itself into the ground on a digital whim. At least with an extra set of wings it would give people a laugh, and we need that in these days of universal Hitler/Trump revulsion.-- xenzag, Feb 23 2020 It wasn't safe before; it's just that now, more people know. But they don't care- not really- because it's going to happen to someone else.
Besides, the people who die in commercial aviation accidents mostly aren't important enough to be worth spending money on. If they were, standards would be higher. After all, they won't spend their own money on their own safety. If you want to travel fast and cheap, the system will stabilize at an acceptable level of fatalities - as it has. It's always been like that, and always will be.
You can already get laughs for free from the Democrats ...
"How to win an election: Step 1- choose a credible candidate ..."
// revulsion //
Sp. "adulation", shirley ?-- 8th of 7, Feb 23 2020 There are some minor copyright issues to overcome, but their best option is to rename the 737-Max the "Airbus A340"-- hippo, Feb 23 2020 //no insurance for the winged coffin// If there were no insurance available for passengers on 737 Maxs, my first step would be to set up an insurance company to cover passengers on 737 Maxs. Wouldn't even need to charge a high premium, as long as I'd cornered the market. Even without any fault- fixing, the 737 Max has a crash rate of 2 in 500,000. So, if you want a million pounds cover, that's going to cost you £4 if I want to break even, or £8 if I want to make a 100% profit.-- MaxwellBuchanan, Feb 23 2020 //rename the 737-Max the "Airbus A340”. With a few bits bolted on, it could be modified to look like one too. That's a good competition entry.-- xenzag, Feb 23 2020 Max - that logic didn’t work so well for Concorde. It had a perfect safety record until one hit a piece of metal on the runway and c’est la vie or rather c’est la mort. The problem here is not numbers, it’s perception. The 737 brand is dead in the water - it’s toxic and no one will risk contamination from any toxic brand, especially when there are other choices. Boeing should get on with cutting them up like I have proposed. I’ll be writing to them and won’t be taking no for an answer!-- xenzag, Feb 23 2020 Yes, but [xen], you said that nobody would be able to get insurance. My point was simply that if insurance were needed, someone would step in and make a profit by providing it.-- MaxwellBuchanan, Feb 23 2020 I just don't understand how it is that when people demand a knee-jerk reaction, they're surprised when they get a knee jerk reaction.
1 June 2009, an Air France A330 flying Rio de Janeiro to Paris as flight AF447 had some problems with sensors; their pitot tubes stopped reporting airspeed. A combination of stupid reactions by the air crew and stupid decisions built into the warning systems resulted in the pilot holding the stick all the way back - forced the plane into a stall, and held it there all the way to the ocean.
Many demands were made that aircraft design be updated so that this could never happen again - if something goes wrong, and the plane can see it's being stalled, the system should take the control away from the pilot and get the nose down.
Well, such a system was designed - but it wasn't implemented, because you have to tell the flight crews about the systems, and if they know there's one that's going to try to take over when it disagrees with the pilot, the pilot is just going to shut it off.
But then along comes the 737 Max, which has a change to the way the engines are mounted - in such a way that it just might put the nose up when you get in some particular flight attitudes. This required the system to have some built-in capability to prevent such a stalling tendency. But also, simultaneously comes along the Max's largest customer, saying (while holding up large $$$) that whatever the fix is, make it look to the pilots like there's been no change, so that training costs are minimal.
Hmmm... automatic nose down, don't tell the flight crews... oh, yeah, we have one of those on the shelf.
Piss on Boeing all you want, but keep in mind that what they produced was precisely to customer spec.-- lurch, Feb 23 2020 [lurch] In which case, Boeing could be criticised for putting the interests of its sales department and its bottom line ahead of the safety of its passengers.-- hippo, Feb 24 2020 I really liked the term "stumpy bus". I get an interesting visual.-- blissmiss, Feb 24 2020 // Boeing could be criticised for putting the interests of its sales department and its bottom line ahead of the safety of its passengers //
By that measure, rain can be criticised for making people wet, and wind for blowing things about ...
Don't forget the shareholders - the manufacturers and the airlines both; but the main pressure comes from the passengers.
If you put two check-in desks next to one another and at one you paid a USD$200 premium for "A statistically safer flight" using a lower-tech less stressed airframe that flew slower, guess where the queue would be ?
Passengers get what they pay for.-- 8th of 7, Feb 24 2020 //convert one into that of a bi-plane.//
This might actually be a goer. Given the issues with the pickle forks in 737 NG airframes <link> it might be prudent to double up on wings and therefore half the stress on the mounting structure. How to go about it? I think a full set of extra wings would be somewhat draggy? How about a nice set of canards? Everyone likes canards, and they'd be a great way to add pitch authority.
//lack competency in stick-and-rudder skills//
The jokes on the stick-and-rudder crowd when the 737 rudder issue rears its head.
//The bigger engines were mounted further forward and higher up on the wing. This gave the plane a tendency to pitch the nose up.//
Something about this doesn't pass the sniff test. Pitch up in response to adding power from underwing engines is as old as underwing engines. It's because you apply force on the end of a lever away from the center of, in this case, drag. Mounting them further forward should make no difference, mounting them higher up on the wing would HELP. Reading around, it seems the nacelles generate lift ahead of the wing, which is the problem. Raising the nose makes the nacelles generate MORE lift, like leading edge extensions. Hence the need to catch it before runaway.
Fundamentally, the 737 has been enlarged to the weight & dimensions of a 757. But, it only has 1/2 the rudder area, 3/5 the horizontal stabilizer area and 1/2 the elevator area. Apparently the trim wheels are miniature too, small enough that you can't apply enough force to move them under aerodynamic loading.-- bs0u0155, Feb 24 2020 // they'd be a great way to add pitch authority. //
Will that be operated by the pilot, or triggered semi-randomly by software ? Just askin' ...
// Mounting them further forward should make no difference //
Yes it does, because it extends the moment of rotation with respect to the mainspar (C of G). The thrust axis is below the C of G and if you move the nozzle (the effective point of action) forward you lengthen the lever.
But as you correctly point out, raising the point of action towards the centreline of the wing does indeed reduce the turning moment.
// has 1/2 the rudder area, 3/5 the horizontal stabilizer area and 1/2 the elevator area //
Oh, but there's so much less drag ...
Look what happened when they tweaked the empennage on the MD-11. It stopped and it dropped and it never flew again ...-- 8th of 7, Feb 24 2020 I still think the bi-plane modification is the way to go, but let's see how Boeing responds.-- xenzag, Feb 24 2020 //Look what happened when they tweaked the empennage on the MD-11//
OK guys, when we made the control surfaces smaller and put in a software fudge, planes crashed and we got in trouble, so let's not do that again OK? Right, does anyone know why the plane with the software fudge and in which everything but the control surfaces was enlarged seems to have got us in trouble?-- bs0u0155, Feb 24 2020 We blame the Marketing department.-- 8th of 7, Feb 25 2020 The air is much thicker now than it used to be, but the metal on the planes has gotten thinner.-- xenzag, Feb 25 2020 The thickness hasn't changed that much; rather, there's much greater use of "lightweight composites" which is a synonym for cardboard dipped in glue.
It's not even particularly good cardboard...-- 8th of 7, Feb 25 2020 I've seen that cardboard, and it's the very best - Kellogg's' Cornflake Boxes, so it's got to be the thicker air.-- xenzag, Feb 25 2020 Xen, the bit about the brand being toxic doesn't make a lot of sense.
Nobody except the frequent fliers really knows what model of plane they'll be on until they're on one and they bother with the emergency exit description card.-- RayfordSteele, Feb 25 2020 //greater use of "lightweight composites" which is a synonym for cardboard dipped in glue.//
I frequently laugh, sometimes out loud, at people who buy carbon fiber bikes, fishing rods and the like. Are you sure you want a bike that can be ruined by dropping it? How competitive is fishing if a 22g saving will help? But I'm fine with composites in aircraft. Aluminium isn't that good. Even the fancy alloys are 50+ years behind the fancy alloys in steel. There are steels with better properties in all parameters apart from, crucially, density. Aircraft are held together with glue already because of unweldable aluminium alloys, and it's the poor aluminium fatigue performance that kills practically every airliner.
With the various composites you gain a real strength-to- weight advantage, you can over build like crazy and still save weight. Not ideal for turbine blades as yet though.-- bs0u0155, Feb 25 2020 // But I'm fine with composites in aircraft. //
If you can afford the short design life and the highly conservative margins of safety that the military adopt, sure. If you can snap the fin off merely by firm use of available rudder authority, that's different.
// There are steels with better properties in all parameters apart from, crucially, density. //
There's a lot of steel in smaller aircraft. Always has been.
// Aircraft are held together with glue already because of unweldable aluminium alloys, //
Partly, but that's also partly because the sections are so thin. You can use the panels from a Bell 206 to wrap your Christmas turkey, but the airframe is actually welded steel tubing.
If you build aircraft to be rugged and resilient, then you can't fly people around so cheaply. If you stick them in cardboard boxes, then you can.
No too many of them die. Shame for the pilots, tho.
But the worst thing is that it enables ordinary people to travel, which is undesirable. Of course, the real mistake is teaching them to read and write ... some of them start to try to think for themselves, and that way disaster lies.
// and it's the poor aluminium fatigue performance that kills practically every airliner. //
Poor fatigue performance in very thin sections. There are a lot of WW2 era aluminium aircraft still flying; tough, solidly made things, with all proper wings and propellers and stuff, not frangible passenger-packets whose designers have been inspired by the tube of Pringles on their desk ...
Worse, they might have been inspired by the actual Pringles, not the tube ... crunch ...-- 8th of 7, Feb 25 2020 random, halfbakery