The iterated version where cargo can split off and land would maybe in some cases be interesting. A drone carrier.
Aerocart cargo gliders
31–40 of 112 posts
Re: Aerocart cargo gliders
#32Earlier quoted context omitted.
In gliding, tow upsets are pretty common and, in rare cases, can be fatal. An out-of-position glider out can _easily_ and very quickly overcome the tow planes elevator authority (ability to pitch up or down) which leads to accidents like this. This video does a good job explaining explaining the root causes and potential dangers ( https://youtu.be/5cpqFzhM9dY?si=J7GxP1dI9Xopy3xu ). Also read the comments from testimo…
> An out-of-position glider out can _easily_ and very quickly overcome the tow planes elevator authority Would this not be trivially solvable with a system that detects the situation (e.g. by measuring the forces acting on the towing plane's attachment point) and detaches the tow? If in the final concept the towed plane would be unmanned and wouldn't contain fuel, even a crash would not be particularly catastrophic.
You misread. It causes the crash of the leading plane, not of the following one, so the glider having no fuel is completely irrelevant
As for a system that measures forces, that’s not likely to work either. Transient forces are OK, but the same force over a little bit of time is enough to force a nose down attitude that is unrecoverable. Attempting to draw the line unequivocally between the two is difficult because it depends on conditions, weights, centers of gravity, and many other things.
Re: Aerocart cargo gliders
#33This concept raises more questions than the site answers:
* what's the point of landing in tow? The safety aspects and the failure modes are enormous
* it's unclear where the 65% fuel saving comes from. Riding the wingtip vortex on the inside produces downward momentum. In order to generate positive lift from the wingtip vortex, the follower has to be outside of it (e.g., gaggles of geese in wedge formation)
* taking advantage of wake flows, while possible (although 65% is highly improbable), would always be less efficient than optimizing a single airframe so that it minimizes the wake generation in the first place
* the site is missing footage of real flights. The 3 clips 10-seconds long are not showing what they claim to be showing. Also, does the "see flight tests" link work for anybody?
Re: Aerocart cargo gliders
#34[deleted]
Re: Aerocart cargo gliders
#35This product is for towing behind another aircraft, but what about winch towing?
A winched glider implements flight with renewable electricity and it does so efficiently because the power and motor never leave the ground!
A glider can climb up to 5000 feet and travel 50x that before making a landing. Wouldn’t it be glorious to see cargo being autonomously slung from site to site across the world, powered entirely by green electricity?
Re: Aerocart cargo gliders
#36Earlier quoted context omitted.
> An out-of-position glider out can _easily_ and very quickly overcome the tow planes elevator authority Would this not be trivially solvable with a system that detects the situation (e.g. by measuring the forces acting on the towing plane's attachment point) and detaches the tow? If in the final concept the towed plane would be unmanned and wouldn't contain fuel, even a crash would not be particularly catastrophic.
You misread. It causes the crash of the leading plane, not of the following one, so the glider having no fuel is completely irrelevant As for a system that measures forces, that’s not likely to work either. Transient forces are OK, but the same force over a little bit of time is enough to force a nose down attitude that is unrecoverable. Attempting to draw the line unequivocally between the two is difficult because i…
They didn't misread, what they're saying is that the lead plane would detect conditions/forces that would result in a tow upset and then cut the tow tether. There's a video in this thread that shows that currently, in manned gliders, the glider pilot can and has a responsibility to release if a tow upset is happening.
Re: Aerocart cargo gliders
#37This product is for towing behind another aircraft, but what about winch towing? A winched glider implements flight with renewable electricity and it does so efficiently because the power and motor never leave the ground! A glider can climb up to 5000 feet and travel 50x that before making a landing. Wouldn’t it be glorious to see cargo being autonomously slung from site to site across the world, powered entirely by…
Do you mean laying out 50 mile long cables from place to place with big engines on the ground that pull in a cable at a couple hundred miles per hour after a plane attaches to it? That wouldn't work. Not even if you skipped tow out a cable from your departure point so it could be reused.
And if you had a track for the cable to run in or a carriage holding the winch to drive travel along, then you would just make it rail freight.
Re: Aerocart cargo gliders
#38This product is for towing behind another aircraft, but what about winch towing? A winched glider implements flight with renewable electricity and it does so efficiently because the power and motor never leave the ground! A glider can climb up to 5000 feet and travel 50x that before making a landing. Wouldn’t it be glorious to see cargo being autonomously slung from site to site across the world, powered entirely by…
Do you mean laying out 50 mile long cables from place to place with big engines on the ground that pull in a cable at a couple hundred miles per hour after a plane attaches to it? That wouldn't work. Not even if you skipped tow out a cable from your departure point so it could be reused. And if you had a track for the cable to run in or a carriage holding the winch to drive travel along, then you would just make it r…
No. Winch glider launches (which are not a new thing) use a ground-based winch to give the glider an initial impulse, and the glider uses that to gain altitude and then glide for a much longer distance.
Re: Aerocart cargo gliders
#39Earlier quoted context omitted.
You misread. It causes the crash of the leading plane, not of the following one, so the glider having no fuel is completely irrelevant As for a system that measures forces, that’s not likely to work either. Transient forces are OK, but the same force over a little bit of time is enough to force a nose down attitude that is unrecoverable. Attempting to draw the line unequivocally between the two is difficult because i…
They didn't misread, what they're saying is that the lead plane would detect conditions/forces that would result in a tow upset and then cut the tow tether. There's a video in this thread that shows that currently, in manned gliders, the glider pilot can and has a responsibility to release if a tow upset is happening.
It. Does. Not. Always. Work!
Read linked NTSB report
(i understand it well - have been flying planes for over 13 year now)
Re: Aerocart cargo gliders
#40"Despite the higher mass, takeoff & climb performance of the consist is similar to that of the lead plane flying independently. This means the consist is capable of taking off on the same runways and with similar climb profiles as the primary tow plane is alone." This is just denying basic physics. Ask any glider pilot how the climb out on aerotow varies based on the weight of the glider being towed.
Perhaps the glider isn't strictly a glider but has some electric assist that's only used for takeoff and initial climbout? Electric achieves unprecedented power per weight when you only need battery for a minute or two.
If you can leave all the endurance for cruise and main climb to the lead plane, electric becomes almost trivial.