The guy’s at Airush caught up with designer Mark Pattison to get the low-down on Airush’s kite canopy development and the Airush Load Frame Technology.
Can you outline some of the key objectives and challenges with canopy development?
For performance you want a kite to be as light as possible; it responds better, drifts better and stays in the air longer. At the same time you want the kite to be as strong as possible. The other challenge is canopy stretch; the kite can get blown out of shape through extended use, which changes the flying characteristics and is obviously problematic in terms of long-term performance.
The demands on the kite canopy are huge when you consider the weight of the fabric is between 50 – 60gms per square meter and less than one millimeter thick. A typical 10m kite would have around 500 grams of canopy, dealing with a working load of around 400 kilograms when under maximum stress – such as a shock load during impact. Generally, canopies are made from polyester as it has the lowest stretch and does not absorb water, however it is still the most fragile part of the kite.
What kills canopies?
Shock load and extended use are obvious problems. But just as, or even more important, is UV damage and leaving your kite flapping.
Does the canopy material have UV stabilizing on it?
Yes, there is a coating on the fabric that limits the impact of harmful UV rays on the cloth but due to the light weight of the fabric, this is difficult to resolve.
What tests are done before manufacturing to ensure that the materials used are consistent in their characteristics?
All the material is tested by the manufacturer and the specification is sent to us for approval. After this, the materials are independently tested and the results cross-correlated. Every batch is inspected prior to production.
All new material will have extensive real-world testing, which is incredibly time consuming. We typically test any new material for a year, evaluate the results across our test locations and then make changes and start the whole process again. At almost any point over the last decade, there would have been one or more test materials or constructions in long-term testing. Within this period we have only accepted two new canopy materials for production.
Talking specifically about the load frame, where or who did the concept come from?
That is a question we get asked a lot with new concepts and innovation. From my perspective, we normally put this down to our outcome as design team and the input from close customers, riders, stores and teachers. We chase innovation through trying to solve a clear problem (such as durability) and ask ourselves tough fundamental questions such as: does our idea bring something new to the customer and does it really matter to them?
It’s not a particularly unique idea in the world of design. It is used extensively in sails, architecture and is a basic structural principle of distribution of planar forces through a membrane structure.
Talking specifically on the load frame, what has been the evolution of the load frame and what have you learned?
From Carbon tape to Dyneema – The early load frames feature carbon tape, but over time we found the Dyneema or UHMPE (Ultra High Modulus Polyethylene) fibers were better at absorbing impact and matching the characteristics of the canopy.
Load Aligned Frame – Over time we were able to improve the alignment of the load frame to increase the stability of the center of effort of the kite by locking in the draft more effectively.
What have been the negatives of the load frame?
Well, it is expensive, it adds around 10% to the selling price of the kite as the frame needs to be very carefully glued and stitched onto the canopy with as few joins as possible, in exactly the right place and with the correct amount of tension. From my perspective I look at this in terms of total costs of ownership, it is still a big win and you get the performance advantages too.
We have had a few stores complain that it extends the life span of the kite so much, that they are losing rebuy customers, who would traditionally rebuy every one to two years and are now waiting longer. Again, as long as they ultimately come back to Airush, we feel we win the long game in terms of customer retention.
You also need to keep in mind that the load frame does not prevent UV damage or damage from flapping and as mentioned earlier, these are significant weaknesses of canopies which we have not been able to completely resolve – yet.
What are the ‘Naysayers’ saying?
Initially, we had people saying its just marketing BS or that the load frame creates a weak point or, even though the kite is stronger, it is more difficult to repair. However, over the years these comments have almost disappeared – of course, it is sometimes difficult to differentiate what people actually believe from what is a well-packaged counter sales argument from any of our competitors.
People also say that it creates a ‘quilting effect’. Do you feel this is relevant?
Not really, keep in mind the canopy is actually stretching significantly less with the Load Frame. It may seem more visible with the additional support but, overall you are getting less stretch – which is ultimately better for the fabric and over time the kite remains much closer to its original design shape and stays like that. Much higher speed machines such as paragliders and foil kites have extensive quilting, from our perspective the benefits from the load frame far out weight the perceived efficiency loss from this.
Why don’t other brands do it, is it patented?
No, it is not patented, but it was extremely complicated to work with our manufacturing partner to do it. It is a concept that has evolved over time and once something is out in the public domain we cannot apply a retrospective patent. It’s also quite obvious, so that also may have limited the possibility of filing a patent.
I really can’t speak on behalf of other brands, as there are some great attempts out there with good designers, also trying to solve the canopy stretch problem.
The canopy materials used – are these lighter than the materials used by other brands that do not use load frame? Or are they the same weight and ‘strength’?
The materials used by some of the other brands is similar in weight.
What durability testing has been done?
We have done extensive long-term benchmark testing, normally within some of our key school and rental locations in Cape Town, Spain, Bali and Australia.
We have also done impact testing, which basically entails crashing the kite continuously into the ground while filming the kite in slow motion to study the effects of the load frame and try to understand what happens to the kite during impact. It is absolutely amazing the distortion on the kite during impact.
In terms of hard numbers, what measurable benefits are there?
Due to the huge number of variables with local conditions at each location and other issues such as long-term UV damage, durability testing is extremely difficult to put a specific number onto any particular kite. Our objective was to get a usable lifespan number on a kite, which we have found, is around double of a similar kite without a load frame and between our test centers, we believe this to be correct.
During lab testing the stretch benefits are significant, if you look specifically at the bias stretch on the canopy (Much of the load frame is bias aligned) you will see around a 30% reduction in bias stretch alone.
What other significant concept has the team worked on in canopies, but have not seen fruition and where do you see the next breakthrough?
Hmmm, not sure how much I can say here as there are a few things I still have hope for. It takes a huge amount of time to develop and test concepts for long-term durability. The other huge challenge is what can we do in production in terms of fabric that is consistent and cost-effective.
Additional UV coatings – We did a fair amount of experimentation with additional UV coatings but these added a lot of weight and ultimately the overall benefits of a heavier fabric (to end at the same given weight) made more sense. For 2019 we introduced the Lithium Progression (Which does not have a load frame) in a fabric, which is 20% heavier, this will improve the overall durability of the fabric and the additional yarn thickness will ultimately improve UV stability.
Hybrid fabrics – We have developed and tested a hybrid fabric that is Dyneema woven into the polyester yarn. Certain results were good, but the flapping tests were very far away from being acceptable and the performance not as good as we hoped. The fabric is very hard to manufacture as the two materials have extremely different characteristics.
Ultra light cloth – With the Load Frame support, we tested and prototyped with lighter cloths (around 30% lighter) but the fabric performance was exponentially worse which is not ideal.
Alternative fabrics – As with ultra light cloths, we have also looked at alternative fabrics such as Nylon, which is not as fragile but has more stretch. The issues have been around Nylon absorbing water and other fabrics not having consistent quality.
Laminates – We have experimented with certain laminates, and so far the durability of a very thin laminate has not been workable in a kite for commercial use. Specifically, if you consider the care needed when storing it, as it would need to be rolled and not folded much.
Of course, these are some of the angles and without constant focus on innovation none of these avenues are a closed door yet. To date, we feel the Load Frame is the biggest step forward that has been made, but we will keep on pushing the boundaries.
This article first appeared on the Airush website here: https://airush.com/innovation-diaries-load-frame-and-canopy-cloth/