This 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?
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.
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.
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.
This seems to be the make-or-break aspect of the entire idea and the claim does seem incredibly suspect to me too. OTOH lying about something basic like this doesn't seem like a viable "business" idea. Is there any more documentation/evidence/explanation available for this?
Also, how much does it decrease the fuel economy of the towing plane?
I sure wouldn't want to be on a Boeing 7XX flight with one of these things in tow. Just imagine the possibility for human and machine error, the plane in tow could cause all manner of issues for the leader.
Ever tried riding a bike and towing someone on another bike or a skateboard? It's perilous. Now do it in the air. Gutsy.
I did a masters on design a autopilot to optimize fuel consumption in formation flight. What is interesting about the aerodynamics is that if placed in the upwash wake of the leader, you are essentially increasing the wing aspect ratio of the system, resulting in gains for both the leader and the follower aircraft. Feels very unintuitive but basically the donut spool is larger and the combined wing is bigger in the spool.
It looks like the prototypes land separately because they are converted aircraft. The production glider uses autopilot and is meant to land behind the main aircraft.
Instead, can we implement autonomous formation flying? Each aircraft can still have its own engines and control, but can make a V shape allowing the following planes to run more efficiently.
This has been attempted (for a military aircraft IIRC), and proved too difficult to be practical. It may now be possible, but it is more challenging that it appears from just watching our feathered friends.
Tow-plane pilot for gliders is a dangerous profession. A simple mistake by the glider pilot can kill the tow plane pilot, with not enough time to react. I saw this happen in person once (https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/G...). Gliders and towing them is neither easy nor safe.
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 testimonials from other glider pilots.
This is my biggest concern with this concept as well. Towing things is challenging because the tow plane's center of gravity can change drastically depending on the forces on the glider it is towing -- if the glider deploys its spoilers / crabs in a crosswind / gets in your wake turbulence you're not going to be able to predict how it changes your CG (and your control authority) without training or experience. Also, with gliders, the tow plane is traveling at around 60MPH to 90MPH, with a decision window of 2-3 seconds. Commercial planes travel at ~500 MPH... The concept seems like a hard sell to the pilot unions. I bet they've thought about this though.
> 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.
The force at the attachment point is constantly changing and depends on several factors.
- the weight of either airplane.
- the performance of the engine on that particular day (varies by altitude / airspeed / temp / mixture / type of fuel / ...)
- the instantaneous weather conditions
- the performance characteristics of either plane.
- slack in the rope (no tension to two times the weight of the glider)
- the glider's towing position (below / above wake)
- crosswinds
- the glider's preferred towing position (depends on visibility from the cockpit, e.g. if someone has a phone or a tablet on the dash, the towing position will be different)
So it isn't really a trivial problem, especially when false positive or false negative will lead to a crash.
notice how he's always on the stick. Also notice how fast it goes from stable to unstable positions.
> even a crash
Recklessness is never the answer in aviation (or coding matter of fact). Practically, good luck convincing insurance to cover a 100 ton (any appreciable cargo load) plane that might fall out of the sky on any property in the general vicinity.
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.
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.
The military gliders made sense because they were landing in hostile territory, usually nowhere near a runway for a return trip. Those gliders were pretty much a one-way, one-time-use vehicle. I guess the Waco glider could be used to argue that towing is technically feasible, but it was intended for a totally different use case. I don't see how it can be argued that it's more economical to run, especially considering the safety issues others have pointed out.
I'm no aerospace engineer but it seems like it would be more efficient to fly one single bigger plane than to tow a second one behind it. I suppose this might appeal to certain groups where they already own a plane, and want to increase capacity without buying a whole new plane. But the idea that it's 65% more efficient just seems pretty sketch. I could totally imagine some drug cartels using these though...
This 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?
Really? Those who have had anything to do with gliders know there is plenty that can and will go wrong. Landing on-tow !?!? And what's the benefit - they might save a little in cruise, but they've got to get there (safely) first?
I'm sure airports will really appreciate half-mile tethers, or whatever length you need for full-sized cargo planes, flopping about the runways (I assume they're aiming for full size because their little graphics doesn't show a little GA thing)
Even assuming a full size one doesn't fatigue off the tail of the lead plane, presumably any time a plane towing one gets into difficulty, the first thing they'll do is cut the towed thing free.
Also the website sounds like it was written by an over-caffeinated estate agent.
Farther down they talk about it being made for the regional cargo market, largely turboprop planes (e.g., Cessna Caravan). That's certainly what the brief video clips show.
I agree, I don’t see this working on existing commercial cargo planes without significant engineering challenges. I also don’t see this working for existing air control systems. I do see it working for private airfields designed for it and tow planes designed for it but that is out of scope. I wonder if they get their own adsb signal?
Yes, this was one of the first things that came to my mind: landing a towed glider right behind a motorized machine is just a bit too adventurous... Especially when winds a not 100 percent in optimum for a safe landing approach. Gliders should always eject mid air an land on their own.. Minimizing risks for any machine or even individuals
Not to mention, what happens in the event of damage to the towed aircraft rendering flight operations impaired such that it affects the towing aircraft?
This 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?
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.
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.
https://glidingschool.com/briefing-winch-launch/
"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.
This seems to be the make-or-break aspect of the entire idea and the claim does seem incredibly suspect to me too. OTOH lying about something basic like this doesn't seem like a viable "business" idea. Is there any more documentation/evidence/explanation available for this?
What is their safety case?
How are they planning to handle aborted takeoffs of towing plane, for example?
How does it integrate with ATC? During towing? During landing of glider?
This video claims that trailer is landing separately and autonomously. Obscure of details. https://www.aerolane.com/news/florida-2025-q1-tests
Also, how much does it decrease the fuel economy of the towing plane?
I sure wouldn't want to be on a Boeing 7XX flight with one of these things in tow. Just imagine the possibility for human and machine error, the plane in tow could cause all manner of issues for the leader.
Ever tried riding a bike and towing someone on another bike or a skateboard? It's perilous. Now do it in the air. Gutsy.
> how much does it decrease the fuel economy of the towing plane
Probably a lot, but I'd assume it is by less than the fuel that 1-2x more planes would use, otherwise there wouldn't be a point to doing this.
I did a masters on design a autopilot to optimize fuel consumption in formation flight. What is interesting about the aerodynamics is that if placed in the upwash wake of the leader, you are essentially increasing the wing aspect ratio of the system, resulting in gains for both the leader and the follower aircraft. Feels very unintuitive but basically the donut spool is larger and the combined wing is bigger in the spool.
It looks like the prototypes land separately because they are converted aircraft. The production glider uses autopilot and is meant to land behind the main aircraft.
Instead, can we implement autonomous formation flying? Each aircraft can still have its own engines and control, but can make a V shape allowing the following planes to run more efficiently.
This has been attempted (for a military aircraft IIRC), and proved too difficult to be practical. It may now be possible, but it is more challenging that it appears from just watching our feathered friends.
I doubt the economics make it a viable use case.
Tow-plane pilot for gliders is a dangerous profession. A simple mistake by the glider pilot can kill the tow plane pilot, with not enough time to react. I saw this happen in person once (https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/G...). Gliders and towing them is neither easy nor safe.
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 testimonials from other glider pilots.
This is my biggest concern with this concept as well. Towing things is challenging because the tow plane's center of gravity can change drastically depending on the forces on the glider it is towing -- if the glider deploys its spoilers / crabs in a crosswind / gets in your wake turbulence you're not going to be able to predict how it changes your CG (and your control authority) without training or experience. Also, with gliders, the tow plane is traveling at around 60MPH to 90MPH, with a decision window of 2-3 seconds. Commercial planes travel at ~500 MPH... The concept seems like a hard sell to the pilot unions. I bet they've thought about this though.
> 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.
The force at the attachment point is constantly changing and depends on several factors.
- the weight of either airplane.
- the performance of the engine on that particular day (varies by altitude / airspeed / temp / mixture / type of fuel / ...)
- the instantaneous weather conditions
- the performance characteristics of either plane.
- slack in the rope (no tension to two times the weight of the glider)
- the glider's towing position (below / above wake)
- crosswinds
- the glider's preferred towing position (depends on visibility from the cockpit, e.g. if someone has a phone or a tablet on the dash, the towing position will be different)
So it isn't really a trivial problem, especially when false positive or false negative will lead to a crash.
Oh btw, it needs to be able to react in milliseconds (so no AI, unfortunately). Here's an example of what an early release looks like btw: https://youtu.be/Gu0mZC2mLEg?si=dzVMxG-rW5624T_m
notice how he's always on the stick. Also notice how fast it goes from stable to unstable positions.
> even a crash
Recklessness is never the answer in aviation (or coding matter of fact). Practically, good luck convincing insurance to cover a 100 ton (any appreciable cargo load) plane that might fall out of the sky on any property in the general vicinity.
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.
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)
I use my cargo gliders only for full scale landing operations.
Reference on their page to the (obvious inspiration) Waco gliders of WWII: https://en.wikipedia.org/wiki/Waco_CG-4
The military gliders made sense because they were landing in hostile territory, usually nowhere near a runway for a return trip. Those gliders were pretty much a one-way, one-time-use vehicle. I guess the Waco glider could be used to argue that towing is technically feasible, but it was intended for a totally different use case. I don't see how it can be argued that it's more economical to run, especially considering the safety issues others have pointed out.
I'm no aerospace engineer but it seems like it would be more efficient to fly one single bigger plane than to tow a second one behind it. I suppose this might appeal to certain groups where they already own a plane, and want to increase capacity without buying a whole new plane. But the idea that it's 65% more efficient just seems pretty sketch. I could totally imagine some drug cartels using these though...
This 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?
Really? Those who have had anything to do with gliders know there is plenty that can and will go wrong. Landing on-tow !?!? And what's the benefit - they might save a little in cruise, but they've got to get there (safely) first?
I'm sure airports will really appreciate half-mile tethers, or whatever length you need for full-sized cargo planes, flopping about the runways (I assume they're aiming for full size because their little graphics doesn't show a little GA thing)
Even assuming a full size one doesn't fatigue off the tail of the lead plane, presumably any time a plane towing one gets into difficulty, the first thing they'll do is cut the towed thing free.
Also the website sounds like it was written by an over-caffeinated estate agent.
Farther down they talk about it being made for the regional cargo market, largely turboprop planes (e.g., Cessna Caravan). That's certainly what the brief video clips show.
I agree, I don’t see this working on existing commercial cargo planes without significant engineering challenges. I also don’t see this working for existing air control systems. I do see it working for private airfields designed for it and tow planes designed for it but that is out of scope. I wonder if they get their own adsb signal?
I imagine these would have to be flown out of specialized cargo airports. It would be a disaster coming out of Commercial airports.
Yes, this was one of the first things that came to my mind: landing a towed glider right behind a motorized machine is just a bit too adventurous... Especially when winds a not 100 percent in optimum for a safe landing approach. Gliders should always eject mid air an land on their own.. Minimizing risks for any machine or even individuals
Not to mention, what happens in the event of damage to the towed aircraft rendering flight operations impaired such that it affects the towing aircraft?
“Oh sh1t!” at 35K feet.
and what happens in the event of a disconnect?
It mentions it has a form of automated control in the tow with "Aerolane's patented Pilot Positioning Assist systems"
This sounds like a free lunch to me.
The iterated version where cargo can split off and land would maybe in some cases be interesting. A drone carrier.
air-train?
Pretty fascinating concept - take what we are already doing on the roads and translate it to the sky. Could lead to huge efficiency gains.