Kites have literally been known for thousands of years. Blimps, or Zeppelins, were thought to be THE means of mass passenger transport in the 1920's and 1930's. One could say that both are an old idea and both were very highly regarded in the past. Kites often had religious significance in Asia. They also had a large contribution to our understanding of the dynamics of modern aircraft configurations. A feit most often overlooked these days (I thought i'd mention it seeing that today it is exactly 111 years ago that Otto Lilienthal crashed and died). Blimps fell out of grace after the horrible incident with the Hindenburg 70 years ago. And even though the concept didnt completely dissapear, none of the modern instances managed to attain the same level of grandeur.So, two old ideas.. and no one ever put them together! you see, that is what I love about science and engineering. You can be standing in the shower and suddenly think up something that has never been done before!
Lately I have been involved in designing a launch system for the Laddermill using a 25-foot helium blimp. It suddenly seemed so obvious. Much of the time, the winds close to the ground are too erratic to launch a kite. But once you manage to get it above 50-100 meters, it'll fly just fine. Getting a kite up to 50 meters in low wind conditions is like trying to get smoke into a coke bottle with a baseball bat! You know the smoke fits in the bottle, you just can't manage to get it in there. Running, pulling on the tethers, giving it slack, running again... this kind of proces is exhausting, and may very well yield no results whatsoever.
In comes the blimp, with its 23 cubic meters of helium, it has a nett. buoyancy of 11kg. We stand and watch how it effortlessly transcends the first 50 meters of altitude. With no fuss it pierces what was for us an impenetrable wall. Fantastic! we can use it to piggy-back a kite to an altitude where there is sufficient clean wind. The kite is a Peter Lynn Venom, a kite in the shape of half a circle. This shape fits nicely over the top of the blimp like a saddle on a horse. All it needs now is to be fixed during ascend and to be released on command. Making use of a few hardpoints on the blimp, carefully taking into account the introduction of potentially large forces into the fragile blimp material (Oh that 1st year mechanics course sure is paying off now :) ), the kite is strapped to its back.
At first, i had expected it all to look a bit comical. But actually, it looks very natural. Like the whole thing is saying to us: why didn't you think of us before? And thus, an old idea solves a new problem. And this is why you should never throw out your old notes. Never discard those old back-of enveloppe sketches. You never know what can bail you out!
Jeroen Breukels.
