… in the ultralight (or microlight) category. The story linked below, complete with photos and video, just came in through YachtPals, a major website dedicated mainly to sailing.
Click here to access this most interesting new (or modernized ?) concept of flying boats.
To be honest, this concept of flying boat caught me by surprise as I read the YachtPals article. Seaplane pilots know that, for specific purposes such as rules of collision avoidance, seaplanes are treated as aircraft when airborne and as vessels when supported by water.
There are other situations where the thin line that separates an aeronautical activity from a marine activity is barely discernible, sometimes to the point of being artificially set by rules for regulatory convenience.
Overall, it is safe to assume the flying boats referred to in the YachtPals’ article would come under the legal definition of an ultralight aircraft. Some of them might even fit in the advanced ultralight aeroplane category, meaning the pilot is allowed to carry a passenger. Furthermore, because of their combination of fuselage and supporting hull, one might be tempted to call them ultralight amphibians except that amphibians generally have the capability of rolling on a hard surface as well, whether ice or ground.
After a little research about terminology usage, I came across a website among several others, called Introduction to Ultralights that seems to put the case to rest: “ultralight seaplanes” include “ultralight amphibians” on the one hand, and “ultralight floatplanes” together with “ultralight flying boats”, on the other hand. The website goes on to define “ultralight flying boat” as follows:
Unlike the amphibians, these aircraft use their fuselage as a floating hull. Often they are flex wing machines and in general are cheaper than the other seaplanes. Most often they can only land on and take off from water.
Back to our main topic, you will notice on the video at the bottom of the Yachtpals web page linked to above under “Click here”, how there appears to be no wind at all nor turbulence during the demo flight. In other words, the video was shot in very favourable weather conditions. It remains to be seen how this ultra-light flying boat would perform and handle in windier conditions and, to make matters more challenging, in turbulent air.
Why raise these two potential issues? Because, ultra-light are generally best flown in smooth air and low wind conditions due to the very light wing-loading that partly defines them from a regulatory perspective.
If YachtPals published this story on their site, they most likely consider this contraption as a boat with wings (see the title YachtPals used: “Dinghies with Wingies”), something that makes total sense from a non-regulatory perspective. Consequently, the definition quoted above would be biased toward boating and read:
Unlike the amphibians, these aircraft use their floating hull as a fuselage. (…)
In other words, the article emphasises an amazing alternative use of inflatable dinghies. Now, what will they find next with the arsenal of floating devices that can also take to the air in a very enjoyable way?
The encouraging part of this concept is that the whole contraption looks fairly simple. It’s basically a powered hang-glider properly affixed to an inflatable dinghy, a stock dinghy by the looks of it. As a result, the cost of owning and flying such a seaplane could in fact be quite reasonable.
I’ve never flown any of these ultralight flying boats. However, I suspect drag and weight to be higher than in the case of an ultra-light amphibian or floatplane of similar size. The combined hull/fuselage component of these ingenious flying machines is streamlined for water use (in the case of a stock inflatable dinghy) but not for flying.
Fortunately, recent models of Rotax engines, for example, provide a power-to-weight ratio sufficient to overcome higher induced drag in critical stages of flight, namely take-off run, climb rate, spread between stall speed and cruise speed, as well as quick go-around capability following a balked approach to land. In other words, though I do not know the actual performance specs of this flying boat, it would seem that its flight envelope is tight.
As for engine-out situations in flight, I’d sure want to know the ultralight’s gliding characteristics. Something tells me that staying close to a safe body of water for landing is the best way to operate this contraption without having to worry about engine problems.
The inflatable dinghy-mounted ultralight is a marvel of creativity, no doubt. However, I have misgiving about adapting the lift components of an aircraft to a main structure that was not meant to be used for flying purposes. In aircraft design terms, it’s sort of putting the cart before the ox. Other than the convenience of being able to take off and land on water using an affordable flotation device, flying performance must be less than ideal, I would imagine. This is perhaps why certain countries, as noted in the YachtPals article, have banned this type of ultralight flying boat.
Such personal misgivings, however, warrant further inquiry, as I do not wish to knock down a potentially good match between boat design and aircraft design, based on incomplete information.
As for the safety record of ultralight flying boats, we’ll most likely have to wait for reliable statistics to be made public.
Having said this, the photos and the video of the ultralight flying boat are compelling to the point where the wide-eyed kid in me secretly dreams of flying the aircraft in calm air, over charming lake-dotted terrain. After all, why would I be blogging about an attention-grabbing flying dinghy ?
PS: Modern flying boats, whether conventional or not, are still being designed and produced. Pictures of such flying boats can be seen here, although the website posting these pictures makes no distinction between a flying boat as such and an amphibian. Instead, it introduces other Canadian and U.S. distinctions or categories presently in use.