Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Petrochemicals on 08/05/2022 23:39:59

Title: Why is leg room on transport so limited ?
Post by: Petrochemicals on 08/05/2022 23:39:59
Why cannot providers of transport vehicles provide users with leg room? Planes and trains seem to wish to encourage knees around earholes. What is the necessity for this?
Title: Re: Why is leg room on transport so limited ?
Post by: vhfpmr on 09/05/2022 01:14:02
To cram more passengers in obviously.

If you increase seat spacing and have fewer seats you lose customers on every full flight, but only benefit <1% of the population who didn't have enough legroom. It's not cost effective.

I'm 6'5", I could write a book about what it's like living in a society of shortarses, but what's the point? Like it or lump it.
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 09/05/2022 15:24:35
This borders on a persistent problem in medical engineering. Whatever assistive device  you design, even without budget constraints, there will always be someone who can't use it, and an understandable and legitimate demand to fulfil the needs of everyone. If you multiply by the requirement for public transport to move people from A to B at a competitive price, you end up designing for  a "90%" passenger (used to be 95% but people have got bigger) of average weight.
Title: Re: Why is leg room on transport so limited ?
Post by: Petrochemicals on 09/05/2022 18:21:42
To cram more passengers in obviously.

If you increase seat spacing and have fewer seats you lose customers on every full flight, but only benefit <1% of the population who didn't have enough legroom. It's not cost effective.

I'm 6'5", I could write a book about what it's like living in a society of shortarses, but what's the point? Like it or lump it.
This borders on a persistent problem in medical engineering. Whatever assistive device  you design, even without budget constraints, there will always be someone who can't use it, and an understandable and legitimate demand to fulfil the needs of everyone. If you multiply by the requirement for public transport to move people from A to B at a competitive price, you end up designing for  a "90%" passenger (used to be 95% but people have got bigger) of average weight.
I hardly think people in 1st class on a plane or train are there because they are over the height average.

Given physics dictates work done is the same for a given weight making a plane a bit longer is not an expense.
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 09/05/2022 23:02:05
Given physics dictates work done is the same for a given weight making a plane a bit longer is not an expense.
Please design my next plane. I would like it the same width (it's a bit snug but comfortable) and a foot longer, but the same weight and therefore the same price. And the additional surface area will not contribute to form drag.
Title: Re: Why is leg room on transport so limited ?
Post by: Petrochemicals on 10/05/2022 00:52:20
Given physics dictates work done is the same for a given weight making a plane a bit longer is not an expense.
Please design my next plane. I would like it the same width (it's a bit snug but comfortable) and a foot longer, but the same weight and therefore the same price. And the additional surface area will not contribute to form drag.
Have done Alan, virtually the same inefficiency due to the fact it is a 2 seater and the only thing changed was a lengthened fuselage, contributing a very very small increace inefficiency due to the drag being effected only by another foot of super slippery paint on an aerodynamic block that already existed.

I also designed an airliner with a spindly appearance, smaller wings, lighter apperatus. Admittedly it is not quite as efficient per person but it is more efficient than a comparable size aircraft. Plus the passengers are far less hassle.
Title: Re: Why is leg room on transport so limited ?
Post by: evan_au on 10/05/2022 08:35:48
Quote from: OP
Why is leg room on transport so limited ?
Because most passengers don't want to pay extra for:
- An emergency exit row
- Business Class
- First Class
- Train as a pilot, so their seat can adjust to a comfortable distance
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 10/05/2022 08:50:20
the only thing changed was a lengthened fuselage, contributing a very very small increace inefficiency
Please let me know where you get your weightless (but stronger) metal from.

I also designed an airliner with a spindly appearance, smaller wings, lighter apperatus.
Would that be a fighter or a rocket, with the addition of your weightless  passenger compartment?

One reason for making planes fatter is the surface/volume ratio. If you double the cross-sectional radius you get 4 times the surface drag but 8 times the payload volume.

One reason for making the wings longer is to increase the lift/drag ratio, which is why a single-seat glider is bigger than a 2-seat powered aircraft,
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 10/05/2022 08:54:02
Train as a pilot, so their seat can adjust to a comfortable distance
But only 20 minutes' holiday when you get there - most of which is spent doing paperwork.

Cabin crew have plenty of space and fewer bowel problems, though the pay isn't as good.
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 10/05/2022 13:10:43
Planes and trains seem to wish to encourage knees around earholes. What is the necessity for this?
Because the bloody passengers never read the safety card or watch the demonstration, so we like to pack them into a brace position before takeoff. The fetal ball is best.
Title: Re: Why is leg room on transport so limited ?
Post by: Petrochemicals on 10/05/2022 19:26:37
the only thing changed was a lengthened fuselage, contributing a very very small increace inefficiency
Please let me know where you get your weightless (but stronger) metal from.
By cunning design lengthening the fuselage has allowed me to make weight savings with regards to stabilisers rudder, elevations and aileron size and therefore thickness, the longer body I have found works to complement aiming the plane. There may be a slight weight penalty but it is insignificant considering

I also designed an airliner with a spindly appearance, smaller wings, lighter apperatus.
Would that be a fighter or a rocket, with the addition of your weightless  passenger compartment?
Similar fashion as the passenger aircraft curre tly operating..

One reason for making planes fatter is the surface/volume ratio. If you double the cross-sectional radius you get 4 times the surface drag but 8 times the payload volume.
the payload has to be powered into flight Alan. If I do not change the csa but lift less weight you should be able to induce less drag.
One reason for making the wings longer is to increase the lift/drag ratio, which is why a single-seat glider is bigger than a 2-seat powered aircraft,

that is correct, I have also thinned the wings in the new plane.
Title: Re: Why is leg room on transport so limited ?
Post by: Petrochemicals on 10/05/2022 19:30:43
Quote from: OP
Why is leg room on transport so limited ?
Because most passengers don't want to pay extra for:
- An emergency exit row
- Business Class
- First Class
- Train as a pilot, so their seat can adjust to a comfortable distance
Business class and first does have significant weight additions with beds etc, but this weight and size remains the same. The emergency exits and aisles I suppose do take up a significant ammount of floor space, but less passengers less toilets less air ducting. Weight is the enemy in flight, not length.
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 10/05/2022 19:59:45
Makes you wonder why nobody has put wings on a train. Bloody engineers, always concerned about physics and safety. Fly the dream!
Title: Re: Why is leg room on transport so limited ?
Post by: Petrochemicals on 10/05/2022 21:48:58
Makes you wonder why nobody has put wings on a train. Bloody engineers, always concerned about physics and safety. Fly the dream!
I have designed a new train..........


https://en.m.wikipedia.org/wiki/A%C3%A9rotrain
Title: Re: Why is leg room on transport so limited ?
Post by: evan_au on 10/05/2022 22:11:26
Quote from: Petrochemicals
I have also thinned the wings in the new plane
The wings are also where they carry most of the fuel.
Is your new plane nuclear-powered? ;)
Title: Re: Why is leg room on transport so limited ?
Post by: Bored chemist on 10/05/2022 22:36:51
Makes you wonder why nobody has put wings on a train. Bloody engineers, always concerned about physics and safety. Fly the dream!
I have designed a new train..........


https://en.m.wikipedia.org/wiki/A%C3%A9rotrain

Essentially the only things you need to know about the "aerotrain";
It failed.
Petrochem thinks it's good.

For what it's worth, he calls this sort of observation "repetitive antagonism" and hides from it.
Title: Re: Why is leg room on transport so limited ?
Post by: Petrochemicals on 10/05/2022 23:37:51
Quote from: Petrochemicals
I have also thinned the wings in the new plane
The wings are also where they carry most of the fuel.
Is your new plane nuclear-powered? ;)
As you may have deduced my plane requires less fuel.
Title: Re: Why is leg room on transport so limited ?
Post by: alancalverd on 10/05/2022 23:51:33
Apropos long airplanes: beware of the rearmost seats in an A380!

If you look at the video display during the cruise you can see that the autopilot is maintaining altitude to as little as ± 1 foot. The sensors and GPS are all located at the sharp end, so the pilots and front passengers get a very smooth ride. But altitude hold is achieved by continuously altering the angle of the stabiliser at the back, so in the slightest turbulence the tail is flapping up and down like a whale.