About 41:20’’ (in French language) from the start of the video about exploring a volcano crater https://www.youtube.com/watch?v=oRi54nYJ92c: “the drone has limits when wind speed is above 8 m/s, while the kytoon can operate with higher winds”.
From this information can we deduce something for AWES, and with various Reynolds number values?
If a drone means quadcopter there may be some limitations, but a drone could look like a plane and in that case wind is a non issue. The kytoon is nice, but its just different tools for different tasks. For non wind related applications I expect the drone would win in most cases due to the intermittency of wind as a fuel.
I dont think there are any general assumptions to be made based on these observations.
I think we (the world) know enough by now to evaluate any concept pretty well on paper. You can’t generalize into a good concept. Making a good concept is like designing a sailboat or architecture for a building. It takes knowledge, skill and talent. But if you could describe a working system, many people should be able to verify its feasibility.
I dont believe kytoons have a place in >MW AWE, due to practical issues of keeping it inflated, and also the availability of gas at scale
What I find instructive in the explanations of the video is the fact that a drone does not hold up with wind, and that it would have destroyed itself under conditions where the kytoon operated.
This ties in with the AWE drone crashes which have been reported, even in a different context, AWES being tethered unlike the drone described on the video.
I do not see how a tethered drone could produce MW reliably and over time regardless of the conditions, whether it is a quadcopter or a plane or both for VTOL operations.
We can therefore deduce from all this a poor future for AWE drones whatever they are, unless spectacular progress related to control.
It is perhaps not for nothing that we do not see a tethered drone when the power kites are legion.
The lesson to be learned is that AWES should limit themselves to what already flies well.
That’s a very bold deduction from one remote data point. The counter arguments in control and capability of other drones is very strongly in favour of them being able to be applied to AWES. … maybe not in the primary generation role but certainly in support of short term airborne tasks if untethered and long term tasks if power is provided.
Thank you for your response, more nuanced than mine.
I will try to give an example of difficulty: we will use VTOL tool when sufficient wind is announced at altitude by taking account of a high cut-in wind speed for a rigid plane or drone; but on the other hand this takeoff mode (and also the transition and the power mode that follow) is difficult in windy conditions, which the video can indirectly confirm.
I’m afraid that this rather favorable concept has nevertheless given its limits, and this under particularly favorable conditions (investments, skills, previous small prototypes…).
Did Windlift do better? It’s hard to know until after full reports.
Perhaps there is some solution by modifying my old FlygenKite (flexible flygen kite system) by using lighter blades like for Daisy.
There are quite a few comparative indications on the different kinds of tethered balloons on
As lifters? With integrated conversion systems?
Great info, Pierre. Years ago, i was considering a similar product from the USA, called SkyDoc:
SkyDoc® Aerostat
Hi Doug,
On the website of Helikite:
Net Curtain Balloons (NCBs)
False claims are sometimes made about Net Curtain Balloons (NCBs) from certain suppliers. Suppliers will promise highly unrealistic wind speed capabilities (such as the ability to fly in hurricanes), make absurd aerodynamic lift claims, give incorrect line angle data, and provide inaccurate stability data.In our tests, it was found that NCBs sometimes fly reasonably well for a while, especially if they are not carrying payload. However, sooner or later a gust of wind comes and then they plummet to the ground, with little self-righting capability.
With payload attached, NCBs could be exceptionally unstable – especially in the kinds of gusty or unstable winds found near buildings, trees, or ships superstructures.[…]
Net Curtain Balloons suffer from a lack of four things:
- Keel for stabilisation of the balloon and payload.
- Kite sail to provide greater aerodynamic lift.
- Stiff spar to provide structure and reliable gravity stability.
- Solid and stable, carbon-fibre Payload Attachment System.
In other words, they suffer from a lack of being a Helikite.
Conventional Tethered Blimps (CTBs)
[…] A well-designed, massive, classic blimp is a good flying machine, when up. The problem is the immense cost, large helium requirement, high manpower and extensive space required. Additionally, they are very difficult to inflate, deploy and retrieve in high winds.
A Helikite of about one third of the size will do the same job far better.
Hi Pierre: Yes I saw that from your original post, and figured you might come back with it. They both seem a bit like something hacked together out of someone’s garage from whatever random parts they had on hand. I really have no way to know what manufacturer’s statements about these devices is true - everyone wants to make the best case possible for their own product. With the helikite, I wonder if some version of it could work better upside-down? it would be nice to see a product that looks a bit more professional and well-developed, and as we who have had a lot of stuff fail in strong winds know, the weather, including wind, sun, rain, snow, hail, etc., is very hard on whatever is put out there, especially thin sheets of material, so I would not expect any of these devices to last very long out in a punishing wind resource. Hard to say, but what you have presented looks very interesting, so thanks for that! 
Both were tested, and the results are related in Design of a one-third scale multi-tethered aerostat system for precise positioning of a radio telescope receiver.
Page 6:
Two different variable lift aerostats, the Skydoc and Helikite were considered. Both are shown in Figure 5. The smaller aerostat on top is the Skydoc aerostat. It is an oblate (flattened) spheroid and its mesh flying harness gives it a pitched orientation which allows its hull to generate lift in a wind field.The lower aerostat is the Helikite and it is a combination of a spheroid aerostat and a kite. It generates lift using its delta wing. The attraction of such aerostats is their ability to maintain a more vertical orientation in high winds. For a conventional aerostat, only the drag increases as the wind speed increases and, as a result, the aerostat loses altitude as the angle of the aerostat tether becomes less and less vertical. To evaluate the performance of the two variable-lift aerostats, experimental tests were performed while towing the aerostats behind a boat. During the tests, poor performance of both aerostats was observed. At high speeds between 40 and 50 km/hr, the aerostats became unstable, and sometimes dove violently all the way to the water surface. Based on these observations it was decided to exclude the variable-lift aerostats from further analysis and instead focus on more conventional spherical and streamlined types.
(2) (PDF) Design of a one-third scale multi-tethered aerostat system for precise positioning of a radio telescope receiver. Available from: https://www.researchgate.net/publication/228560180_Design_of_a_one-third_scale_multi-tethered_aerostat_system_for_precise_positioning_of_a_radio_telescope_receiver [accessed Oct 17 2024].
“At high speeds between 40 and 50 km/hr, the aerostats became unstable, and sometimes dove violently all the way to the water surface. Based on these observations it was decided to exclude the variable-lift aerostats from further analysis and instead focus on more conventional spherical and streamlined types.”
The least we can say is that it is not very encouraging to operate a wind turbine permanently in the air under these kytoons.
Well, there’s a project: Come up with a better Kytoon design.
Just saw this now-old video of that ass-shaped double blimp/airship crashing:
Understanding the Airlander 10 Crash | Watch (msn.com)
