Retro Button Would Further Automation On the Boeing Max & Ev

[Riley Angel]

On 2019-03-17 13:52, Bret Cahill wrote:

4. Increased Safety. If a fan blade snaps off it can't impale any passengers or critical structures.

Shedding a fan blade leads to rapid destruction of turbines caused by
loss of balance anyway.

Much much less of an issue with larger ductless fans.

<snip exciting stuff about Newton's Second Law>

If you think that a turbine can continue to operate after it has shed a
blade, you have another thing coming, fan or gas-generator alike.
Containment is nice, but the unit is scrap very shortly afterwards
either way.

They're simply not designed to operate with any significant
out-of-balance forces present, and if the rest of the fan or turbine is
subjected to ingestion of the bit that fell off becasue it was
contained, it goes much wronger much quicker. These things self-destruct
after eating a decent amount of bird matter, let alone chunks of metal.

 

[Riley Angel]

On 2019-03-19 10:14, Bret Cahill wrote:

They can do precision vertical and near vertical landings now. They just don't know it.

Boeing might be looking for some new engineers shortly. You should let
them know about your insights.

 

[Bonk]

On 03/19/2019 06:56 PM, Riley Angel wrote:

On 2019-03-19 10:14, Bret Cahill wrote:

They can do precision vertical and near vertical landings now. They just don't know it.


Boeing might be looking for some new engineers shortly. You should let
them know about your insights.

I think the Stratosphere Tower in Las Vegas is the place for this. They
have some other thrill rides on the roof already.

https://www.stratospherehotel.com/ThrillRides

 

[Bret Cahill]

4. Increased Safety. If a fan blade snaps off it can't impale any passengers or critical structures.

Shedding a fan blade leads to rapid destruction of turbines caused by
loss of balance anyway.

Much much less of an issue with larger ductless fans.


snip exciting stuff about Newton's Second Law

If you think that a turbine can continue to operate after it has shed a
blade,

You'd be surprised.

§ 33.94. Based on a margin of safety (MS) analysis, the most critical compressor, turbine or fan blade at its maximum permissible rotating speed must be contained by the casings while the engine should operate continuously for at least 15 s.

https://www.sciencedirect.com/science/article/pii/S100093611200009X

And this isn't an enclosed compressor or turbine blade.

It's a blade on a 3X larger ductless fan where the imbalances forces from one blade getting tossed clear are at least an order of magnitude less than the low bypass ratio GE 90.

If passengers find the vibration annoying the pilot lands on an airstrip, gets his Allen wrench out, removes what's left of the broken blade and the blade opposite the broken blade.

Then he emails his airline to have a blade or 2 ready at the next roof top.

He may need to borrow a ladder from the locals to reach the Allen bolts but that's still safer than dragging turbo fans down the runway.


Bret Cahill

 

[Bonk]

On 03/19/2019 10:24 PM, Bret Cahill wrote:

4. Increased Safety. If a fan blade snaps off it can't
impale any passengers or critical structures.


Bret Cahill

5. When the power fails in VTOL mode it won't autorotate, and it won't
glide.

 

[Bret Cahill]

4. Increased Safety. If a fan blade snaps off it can't
impale any passengers or critical structures.


Bret Cahill

5. When the power fails in VTOL mode it won't autorotate, and it won't
glide.

With large fans one engine will be enough for take off or landing.

 

[Bret Cahill]

4. Increased Safety. If a fan blade snaps off it can't
impale any passengers or critical structures.

5. When the power fails in VTOL mode it won't autorotate, and it won't
glide.

For a quick pre take off check the pilot first runs the engines at max locked in the launcher. The plane is only released at a somewhat lower safer RPM still well above take off thrust. Maximum power is only used for this test and is not necessary or desirable for the rest of a fuel efficient flight.

The props on an Osprey would hit the runway if they aren't tilted back a little. The fans are fixed here so, if you don't want 1 story high landing gear, it's the same situation as an Osprey that somehow got rotors stuck in horizontal flight.

Fans always need to be strong enough to chop up birds, but, without landing gear, they need to disintegrate like tempered glass when they first contact the runway in emergency landings so large shards don't impale passengers in the aft cabin.


Bret Cahill

 

[Bonk]

On 03/20/2019 11:57 AM, Bret Cahill wrote:

4. Increased Safety. If a fan blade snaps off it can't
impale any passengers or critical structures.

5. When the power fails in VTOL mode it won't autorotate, and it
won't glide.

For a quick pre take off check the pilot first runs the engines at
max locked in the launcher. The plane is only released at a somewhat
lower safer RPM still well above take off thrust. Maximum power is
only used for this test and is not necessary or desirable for the
rest of a fuel efficient flight.

The props on an Osprey would hit the runway if they aren't tilted
back a little. The fans are fixed here so, if you don't want 1 story
high landing gear, it's the same situation as an Osprey that somehow
got rotors stuck in horizontal flight.

Fans always need to be strong enough to chop up birds, but, without
landing gear, they need to disintegrate like tempered glass when they
first contact the runway in emergency landings so large shards don't
impale passengers in the aft cabin.

I read that Osprey blades disintegrate into broomstraws.

You lose far more than half the performance if you lose one of your two
engines. The second engine just brings you to the crash site, as they say.

You'll want at least collective pitch control on your 100 fan blades.
Probably cyclic control too. Lose a single blade, and you may lose
control of all the rest.

A helicopter rotor disk is mostly empty space, and your fan disks are
mostly solid. This isn't going to autorotate. Won't glide either unless
you can stop the fans and feather all those blades.

But I don't want to discourage you.

 

[Bret Cahill]

4. Increased Safety. If a fan blade snaps off it can't
impale any passengers or critical structures.

5. When the power fails in VTOL mode it won't autorotate, and it
won't glide.

For a quick pre take off check the pilot first runs the engines at
max locked in the launcher. The plane is only released at a somewhat
lower safer RPM still well above take off thrust. Maximum power is
only used for this test and is not necessary or desirable for the
rest of a fuel efficient flight.

The props on an Osprey would hit the runway if they aren't tilted
back a little. The fans are fixed here so, if you don't want 1 story
high landing gear, it's the same situation as an Osprey that somehow
got rotors stuck in horizontal flight.

Fans always need to be strong enough to chop up birds, but, without
landing gear, they need to disintegrate like tempered glass when they
first contact the runway in emergency landings so large shards don't
impale passengers in the aft cabin.

I read that Osprey blades disintegrate into broomstraws.

Military hardware is supposed to be dangerous. It's considered "romantic" when poor troops get needlessly killed.

You lose far more than half the performance if you lose one of your two
engines. The second engine just brings you to the crash site, as they say.

At least as safe the standard 2 conventional wing mounted ducted fans where a lot of rudder is required to fly on one engine.

No rudder is necessary here.

> You'll want at least collective pitch control on your 100 fan blades.

Why?

Probably cyclic control too. Lose a single blade, and you may lose
control of all the rest.

Any imbalance forces from the loss of a blade are well over an order of magnitude less than a smaller low bypass fan like the GE 90.

A helicopter rotor disk is mostly empty space, and your fan disks are
mostly solid. This isn't going to autorotate.

Why would there be much of a need to auto rotate? It only spends a few seconds near vertical.

> Won't glide either

Passenger airliners spend a lot of time gliding?

unless
you can stop the fans and feather all those blades.

But I don't want to discourage you.

That's obvious as you haven't provided any argument on why this isn't at least as safe as conventional wing mounted ducted fans.


Bret Cahill

 

[Bonk]

On 03/20/2019 09:05 PM, Bret Cahill wrote:

4. Increased Safety. If a fan blade snaps off it
can't impale any passengers or critical structures.

5. When the power fails in VTOL mode it won't autorotate, and
it won't glide.

For a quick pre take off check the pilot first runs the engines
at max locked in the launcher. The plane is only released at a
somewhat lower safer RPM still well above take off thrust.
Maximum power is only used for this test and is not necessary or
desirable for the rest of a fuel efficient flight.

The props on an Osprey would hit the runway if they aren't
tilted back a little. The fans are fixed here so, if you don't
want 1 story high landing gear, it's the same situation as an
Osprey that somehow got rotors stuck in horizontal flight.

Fans always need to be strong enough to chop up birds, but,
without landing gear, they need to disintegrate like tempered
glass when they first contact the runway in emergency landings so
large shards don't impale passengers in the aft cabin.

I read that Osprey blades disintegrate into broomstraws.

Military hardware is supposed to be dangerous. It's considered
"romantic" when poor troops get needlessly killed.

The broomstrawed blades flail around, and remain attached.

You lose far more than half the performance if you lose one of your
two engines. The second engine just brings you to the crash site,
as they say.

At least as safe the standard 2 conventional wing mounted ducted fans
where a lot of rudder is required to fly on one engine.

No rudder is necessary here.

No climb performance with one. Might maintain altitude. At least it will
descend at a lower rate enroute to the crash site.

You'll want at least collective pitch control on your 100 fan
blades.

Why?

For instant response while taking off and touching down. The fans, and
these are big ones, aren't going to spin up or down quickly. But they'll
be good flywheels and hold RPM while changing blade pitch gives
precision control.

Probably cyclic control too. Lose a single blade, and you may lose
control of all the rest.

Any imbalance forces from the loss of a blade are well over an order
of magnitude less than a smaller low bypass fan like the GE 90.

The mess of pitch linkages between blades might not let one go cleanly
without jamming up the whole works.

A helicopter rotor disk is mostly empty space, and your fan disks
are mostly solid. This isn't going to autorotate.

Why would there be much of a need to auto rotate? It only spends a
few seconds near vertical.

That's when the power fails! Near the ground, with no forward speed.
Even if you could knock it over to horizontal in a split second... what now?

Won't glide either

Passenger airliners spend a lot of time gliding?

When they have to. They have a pretty good range too.
But this craft, with huge drag rings encircling it, is doomed.

unless you can stop the fans and feather all those blades.

But I don't want to discourage you.

That's obvious as you haven't provided any argument on why this isn't
at least as safe as conventional wing mounted ducted fans.

I want blimps to come back.

 

[Bret Cahill]

4. Increased Safety. If a fan blade snaps off it
can't impale any passengers or critical structures.

5. When the power fails in VTOL mode it won't autorotate, and
it won't glide.

For a quick pre take off check the pilot first runs the engines
at max locked in the launcher. The plane is only released at a
somewhat lower safer RPM still well above take off thrust.
Maximum power is only used for this test and is not necessary or
desirable for the rest of a fuel efficient flight.

The props on an Osprey would hit the runway if they aren't
tilted back a little. The fans are fixed here so, if you don't
want 1 story high landing gear, it's the same situation as an
Osprey that somehow got rotors stuck in horizontal flight.

Fans always need to be strong enough to chop up birds, but,
without landing gear, they need to disintegrate like tempered
glass when they first contact the runway in emergency landings so
large shards don't impale passengers in the aft cabin.

I read that Osprey blades disintegrate into broomstraws.

Military hardware is supposed to be dangerous. It's considered
"romantic" when poor troops get needlessly killed.

The broomstrawed blades flail around, and remain attached.

They already solved that issue! Can they do anything about the dust?

You lose far more than half the performance if you lose one of your
two engines. The second engine just brings you to the crash site,
as they say.

At least as safe the standard 2 conventional wing mounted ducted fans
where a lot of rudder is required to fly on one engine.

No rudder is necessary here.

No climb performance with one.

Higher bypass = faster climb. That's not in dispute.

What's in dispute is keeping the engines on the wings.

> Might maintain altitude.

If you don't have the numbers it's best to just stick to greater than and less than logical decisions.

At least it will
descend at a lower rate enroute to the crash site.

What's surprising is how often a lot of people can survive crashes.

Best listen to the flight attendant.

You'll want at least collective pitch control on your 100 fan
blades.

Why?

For instant response while taking off and touching down.

Faster, cheaper and more reliable to use control surfaces.

The fans, and
these are big ones, aren't going to spin up or down quickly. But they'll
be good flywheels and hold RPM while changing blade pitch gives
precision control.

Control surfaces are proven technology. The Wright Bros used them.

Probably cyclic control too. Lose a single blade, and you may lose
control of all the rest.

Any imbalance forces from the loss of a blade are well over an order
of magnitude less than a smaller low bypass fan like the GE 90.

The mess of pitch linkages between blades might not let one go cleanly
without jamming up the whole works.

There's no duct so it just flings free of the rotor. Even if it grazes a wing it won't be a straight on collision.

A helicopter rotor disk is mostly empty space, and your fan disks
are mostly solid. This isn't going to autorotate.

Why would there be much of a need to auto rotate? It only spends a
few seconds near vertical.

That's when the power fails!

Why wouldn't the engine fail during the maximum rpm test conducted when the plane is restrained in the launcher?

Again, there is more than enough thrust for take off at a lower safer fuel efficient rpm.

> Near the ground, with no forward speed.

Exactly vertical may not be necessary or even desirable.

> Even if you could knock it over to horizontal in a split second... what now?

How's it any different than any other conventional aircraft flying horizontal?

Won't glide either

Passenger airliners spend a lot of time gliding?

When they have to.

Post some youtube videos of large passenger aircraft gliding.

> They have a pretty good range too.

Fuel is 80% of airline operating cost. If you ever get much altitude gliding a thermal, demand a partial refund of your ticket.

Just don't mention my name.

> But this craft, with huge drag rings encircling it, is doomed.

Why can't the fans be geared together like a tandem version of the Osprey?

If one engine goes down you still have an operational aircraft.

unless you can stop the fans and feather all those blades.

But I don't want to discourage you.

That's obvious as you haven't provided any argument on why this isn't
at least as safe as conventional wing mounted ducted fans.

I want blimps to come back.

They need even more monstrously yuge propulsion surfaces. I'd look into making the blades out of inflatable rubber.


Bret Cahill

 

[Bret Cahill]

https://www.latimes.com/local/california/la-fi-boeing-max-design-20190315-story.html

If they want to increase fuel efficiency with big fans they need to _really_ start from scratch:

Instead of pussy footing around with incremental increases in bypass ratio GE, RR, Boeing, Airbus and any rooftop not big enough for a real airport need to get together to rethink the entire aviation system.

Put the fuselage inside of 2 counter rotating fans and the core engines in tandem inside of the fuselage, geared together in case one engine fails like the Osprey. The engine room would split the cabin area in two displacing a few dozen seats so the wide body version would have a for cabin and an aft cabin, bathrooms and crews etc.

1. A yuge increase in bypass ratio / fuel savings.

2. Reduced the drag from the engines as ducting is no longer necessary.

3. High low speed thrust for safe VTOL.

4. Increased Safety. If a fan blade snaps off it can't impale any passengers or critical structures.

5. Possible noise reduction opportunities

Then they have two options:

1. Conventional landing gear and runways.

2. Dedicated space saving launch pads that load passengers while the craft is horizontal then, after everyone is strapped in, rotates for VTOL from building roofs.

There may be a military advantage putting large planes on small ships. After it proves to have a good safety record in the navy, then go civilian - commercial with a derivative.

Placing the engine in the fuselage takes up a few dozen seats, but there should be space in the engine room for checked on baggage.

Notice the 30 MW core engine isn't very large w/o the runway dragging fans:

https://www.yahoo.com/news/pilots-searched-checklist-lion-air-crash-indonesian-investigators-102059439--finance.html


Bret Cahill

 

[Bonk]

On 03/20/2019 11:02 PM, Bret Cahill wrote:

You'll want at least collective pitch control on your 100 fan
blades.

Why?

For instant response while taking off and touching down.

Faster, cheaper and more reliable to use control surfaces.

The fans, and these are big ones, aren't going to spin up or down
quickly. But they'll be good flywheels and hold RPM while
changing blade pitch gives precision control.

Control surfaces are proven technology. The Wright Bros used them.

The fan blades /are/ the control surfaces. During the time it's
vertical, this is a helicopter.


<https://en.wikipedia.org/wiki/CFM_International_LEAP> has this:

"The fan has flexible blades manufactured by a resin transfer molding
process, which are designed to untwist as the fan's rotational speed
increases."


You're going to twist and untwist yours too. But you can't afford to
wait for the fan's rotational speed changes.

 

[Bonk]

On 03/20/2019 11:02 PM, Bret Cahill wrote:

But this craft, with huge drag rings encircling it, is doomed.
Why can't the fans be geared together like a tandem version of the Osprey?

If one engine goes down you still have an operational aircraft.

With no engines, it's a windmilling prop. It's worse than that, two
counter-windmilling props.

unless you can stop the fans and feather all those blades.
But I don't want to discourage you.
That's obvious as you haven't provided any argument on why this isn't
at least as safe as conventional wing mounted ducted fans.
I want blimps to come back.
They need even more monstrously yuge propulsion surfaces. I'd look into making the blades out of inflatable rubber.

This got me thinking. You could charge a blimp like a balloon, rub it
with some wool. Then send it up, and it would be propelled by Earth's
magnetic field.

 

[Bonk]

On 03/17/2019 11:09 AM, Bret Cahill wrote:

Put the fuselage inside of 2 counter rotating fans and the core
engines in tandem inside of the fuselage, geared together in case one
engine fails like the Osprey. The engine room would split the cabin
area in two displacing a few dozen seats so the wide body version
would have a for cabin and an aft cabin, bathrooms and crews etc.

I think this would work.

 

[Bret Cahill]

Put the fuselage inside of 2 counter rotating fans and the core
engines in tandem inside of the fuselage, geared together in case one
engine fails like the Osprey. The engine room would split the cabin
area in two displacing a few dozen seats so the wide body version
would have a for cabin and an aft cabin, bathrooms and crews etc.

I think this would work.

They can start off with a small drone before going to a full size drone, although, the small drone step isn't really necessary unless they need small drones. They pretty much know how everything will work long before anyone ever touches a single piece of material. The entire navy is going to drones. Why be anywhere you don't want to be?

Obviously you cannot plug an after burner, even partially, but there may be an opportunity to adapt this technology for commercial aviation:

https://www.fastcompany.com/90316833/scientists-have-discovered-a-shape-that-blocks-all-sound-even-your-co-workers

Ductless fans are noisy no matter how or where you put them on an aircraft.


Bret Cahill

 

[Bonk]

On 03/22/2019 11:11 AM, Bret Cahill wrote:

Obviously you cannot plug an after burner, even partially, but there may be an opportunity to adapt this technology for commercial aviation:

https://www.fastcompany.com/90316833/scientists-have-discovered-a-shape-that-blocks-all-sound-even-your-co-workers

!!! fantastic !!!

I want that on my motorcycle.

 

[Bret Cahill]

https://www.latimes.com/local/california/la-fi-boeing-max-design-20190315-story.html

If they want to increase fuel efficiency with big fans they need to _really_ start from scratch:

Instead of pussy footing around with incremental increases in bypass ratio GE, RR, Boeing, Airbus and any rooftop not big enough for a real airport need to get together to rethink the entire aviation system.

Put the fuselage inside of 2 counter rotating fans and the core engines in tandem inside of the fuselage, geared together in case one engine fails like the Osprey. The engine room would split the cabin area in two displacing a few dozen seats so the wide body version would have a for cabin and an aft cabin, bathrooms and crews etc.

1. A yuge increase in bypass ratio / fuel savings.

2. Reduced the drag from the engines as ducting is no longer necessary.

3. High low speed thrust for safe VTOL.

4. Increased Safety. If a fan blade snaps off it can't impale any passengers or critical structures.

5. Possible noise reduction opportunities

Then they have two options:

1. Conventional landing gear and runways.

2. Dedicated space saving launch pads that load passengers while the craft is horizontal then, after everyone is strapped in, rotates for VTOL from building roofs.

There are only 2 - 3 options for combining the engine area with the rest of the plane:

If you want radially symmetric centrally mounted engines with the fan on a drive shaft then you need an exo skeletal structure to go over the fan. Otherwise the fan is mounted on a ring gear and the engines off center.

 

[Bret Cahill]

https://www.latimes.com/local/california/la-fi-boeing-max-design-20190315-story.html

If they want to increase fuel efficiency with big fans they need to _really_ start from scratch:

Instead of pussy footing around with incremental increases in bypass ratio GE, RR, Boeing, Airbus and any rooftop not big enough for a real airport need to get together to rethink the entire aviation system.

Put the fuselage inside of 2 counter rotating fans and the core engines in tandem inside of the fuselage, geared together in case one engine fails like the Osprey. The engine room would split the cabin area in two displacing a few dozen seats so the wide body version would have a for cabin and an aft cabin, bathrooms and crews etc.

1. A yuge increase in bypass ratio / fuel savings.

2. Reduced the drag from the engines as ducting is no longer necessary.

3. High low speed thrust for safe VTOL.

4. Increased Safety. If a fan blade snaps off it can't impale any passengers or critical structures.

5. Possible noise reduction opportunities

6. Big prop-fans eliminate stall issues

https://www.yahoo.com/news/737-max-crash-details-reveal-000703550.html

Just gun the engines and the control surfaces start working.

Then they have two options:

1. Conventional landing gear and runways.

2. Dedicated space saving launch pads that load passengers while the craft is horizontal then, after everyone is strapped in, rotates for VTOL from building roofs.


Bret Cahill

 

[Bret Cahill]

Put a retro or "my kingdom for a horse" switch on anything that seems unnecessarily over automated or when the additional sophistication is of a minor advantage.

If anything doesn't seem perfect, tap the retro switch and you are back to flying by the seat of your pants or at least something that is less complicated / more proven technology.

It may seem counter intuitive but this would actually _further_ automation and sophistication by taking some of the pressure off the designers trying to get every unanticipated situation right the first time.

It may also reduce some of the concerns about AI.

It's astounding this isn't SOP in every design engineering dept.

Not sure of the hold up here. Has anyone heard of any active patents on retro buttons?

"The issue, which surfaced during FAA simulator testing, concerns the ability of pilots to quickly reassert control of the plane if an automated flight handling system pushes the plane downward, said a person familiar with the matter."

https://news.yahoo.com/us-faa-boeing-must-address-issue-737-max-052756185.html

Just put the retro button in and call it a day.


Bret Cahill