AT CAD Team/Aircraft   

Aircraft can be used in a appropriate context, if the aircraft is used for specific tasks such as delivery of cargo or personnel to remote villages. Similar to bush aircraft, a time schedule can then be used. Personal microlight aircraft may also be useful (used similar to a personal air vehicle), but only to a lesser extent.

[edit] Appropriateness

[edit] Weight and cost

Besides the requirements noted above, the aircraft also needs to be designed as cost/effective as possible. At present, most contemporary aircraft have been made heavy, resulting in a airplane that is very costly to make, as well as to propel (very powerful engines are required). Aircraft such as the Gossamer Condor too are still too expensive to built, require a lot of landing area, and are very fragile (due to their very long wings). Aircraft which have a good ratio between the mentioned issues are the so-called "flexwing microlights", however even these are made with expensive materials and are sold at high prices by commercial companies, making them again inappropriate for use (average cost= 30000$). Aircraft that might of fallen in the category of being usable as "appropriate technology" on many criteria (fairly good usability, relatively cheap and DIY constructable) are the airplanes built at the beginning of aviation (ie Blériot IX, Wright Flyer, Avro Type F, ...) Many of these airplanes were also biplanes, meaning that they had more lift with less long wings. Sadly enough, these aircraft do not provide enough safety (they were even dangerous to experienced flyers) and are also only suitable to carry but 1 or two persons (restricting their applications). Aircraft invented later (1914, ...) too became inappropriate as they again became too heavy.

[edit] Safety

The weights described above are in part a response to safety requirements. Light aircraft and early models of aircraft have poor safety records. Modern commercial airliners have a very good safety record, but at the cost of weight and therefore cost and fuel efficiency.

Nonetheless fuel efficiency has improved over the decades, through advances in design and technology that allow improvements in safety at the same time as the tradeoff of strength and weight, and engine efficiencies.

[edit] Theory of flight

In order to attain flight, two main things are required, namely engine power and wing surface area. Thus, increasing the surface area will decrease the required engine power and vice versa. Indeed, trough projects such as the Gossamer Condor, we see that even with very little engine power (0,4 HP)^[1], aerial transport is possible. However, the more wing area, the less agile the airplane is, and the more space it requires to land. Also, the more air resistance there is and the more strain is put on the wings (important depending on the materials used to make the wings). Finally, the larger we make the wings, we higher the cost (although as less fuel is used to propel the airplane, this amount is actually recovered if we assume to use it for meaningful tasks and if the airplane is durable enough to last a while).

P < sub > d < / sub > = F < sub > d < / sub > .V = 1 / 2pv < sup > 3 < / sup > AC < sub > d < / sub > ^[2] in which:

• P= power to overcome
• d= drag
• F= force of
• p= density of the fluid/gas
• v= speed of the object relative to the fluid/gas
• A= reference area
• C= coefficient

Generally, the amount of power required to get an microlight flexwing airborne is around 25 HP /100 kg ? ^[3][4], ^[5]

lift-to-drag and thrust to weight ratio needs explaining

Another very important issue is the wing profile, information on how to achieve this can be found at http://en.wikipedia.org/wiki/Talk:Wing#Wing_materials_and_construction_types Another important thing to keep in mind is that longer wings do not add weight, where wider wings do, the reason why professional glider planes have long wings instead of wide ones. Wider wings however allow the wing to take more pressure per m², meaning higher speeds are possible, and less sturdy wing materials can be used.

[edit] Approach

Given the difficulties noted above an obvious solution would be to design a new freight aircraft, and maintain a smaller low-cost microlight for private use. A newly designed freighter airplane would be best simply because the range would be larger aswell as the payload (= smaller cost). Also fewer pilots are required.

[edit] Freighter aircraft construction

Current large aircraft aren't generally ultralights, so I first looked at the option of using a WW2 miltary glider design (http://en.wikipedia.org/wiki/List_of_World_War_II_military_gliders ). These were lighter since they were made from wood. However, since even these might be too heavy (they require a lot of engine power), I think it would be better to simply use an older aircraft design (pré-WW1) and update these with existing ultralight-technology/construction methods. Older aircraft designs were very lightweight and still capable of taking a large load, and combining this with ultralight construction could make a very cost-effective combination. For example, Igor Sikorsky's Il'ya Muromets had (fully loaded) a weight of 5400 kg, yet was still powered by only 4 x 100 HP. This was btw a very old design, newer designs such as the Caproni Ca.1/ Ca.3 were even more suitable, and many improvements can also be integrated such as a suitable wing profile (invented only in the 1930's, can be generated by computer, See: this wikipedia entry), a closed compartment for the cargo (increases efficiency, see ie the Avro type F, http://freespace.virgin.net/pbratt.home/Avro%20Type%20F%203D%20Aircraft%20Model%203DS%20MAX%20LWO%20C4D.htm compared to ie the Demoichelle; if you recalculate the weight) and perhaps a higher wing/weight ratio (the Gossamer Condor, and common professional gliders demonstrated/demonstrate the value of this; ie glide number 50-60). Finally, I think it's best to also make the aircraft more environmentally friendly (where possible). This would involve the use of cradle-to-cradle materials (which shouldn't be too hard since most older airplane materials were, sail however needs to be swapped, Dacron can't be used) and possibly a different fuel (later-on; the list of possible fuels is available at Comparison of alternative ICE fuels).

To built a appropriate freighter aircraft, it is important to first assess the payload required. With this number, we can then scale a pré-WW1 design to fit our requirements.

ie --> payload: 1000 kg ? --> duration of flight: ? hours (= ? km range) --> speed: ? km/u (remember: the lower= the less engine power is required) --> engine: ? HP

As a guideline: the Caproni Ca 42 had 3 x 270 HP (pré-WW1, max weight: 7500 kg), Gotha G.V had 2 x 260 HP (max weight 3976 kg ), the Waco CG-4 (actually XPG-2A) had 2 x 200 HP (max weight 3400 kg, loaded)

[edit] The microlight aircraft

Improved single person airplane design "AltAÏR" & "ErdieBirdie", two possibilities sketched

Side view of the designs

The DIY APEV Demoichelle or Pouchel light/Pouchelec ^[6] microlights are currently the most appropriate airplanes for the transport of only 1 person. Other microlights which could possibly be used include DIY microlights as the http://en.wikipedia.org/wiki/Beaujon_Enduro Perhaps that comparable aircraft can also be made DIY based on designs as the http://en.wikipedia.org/wiki/Eipper_Quicksilver , http://www.aerolite103.com/ , ... To built these aircrafts, besides following the on-line manuals to construct the fuselage, an engine can be chosen as discussed at Comparison of IC engines. Wing warping is probably best used instead of flaps, given the decreased weight. Also, the best possible design, would also include a cabin (similar to the Avro Type F, if possible without being completely closed, letting some air trough between wing and fuselage, similar to a parasol wing) and 2 propellers, next to the fuselage (allowing air to be easily sucked in by the propellers, as apposed to a propeller right after the fuselage). Propellers can be mounted on the wings and powered by the engine via a chain (similar to the Wright Flyer 3). Perhaps a second wing can be added, making the airplane a biplane, allowing the use of an even lighter engine, or the possibility to carry (some limited amount of) cargo. Perhaps a 3D model can be made called the "Wright Enduro".

[edit] DIY UAS

See DIY UAS

[edit] Airship

See AT airship

[edit] Landing space & autogiro

One particular issue for single-person aircraft is the landing space required for the aircraft. In urban centers, often so little space is available that one might think VTOL (vertical take-off and landing) is a bare necessity. As such, there is the thought of also designing a AT Autogiro^{[7][8][9][10][11]}; however a regular microlight airplane can still be integrated in urban centers, despite the "lack" of space. An easy solution is to simply use the roads to land on, ie by modifying the traffic lights to indicate that a portion of the road can not be used (very) temporarily. This can be done wirelessly, allowing a pilot to switch the traffic light to red when he's on his approach. After landing (on a road at the outskirts of the city), the aircraft can be placed on a parking space, and the "last mile" trip to the city center can be done either using public transport, or with a secundairy vehicle taken along in the aircraft (ie roller skates, electric skateboard, ...) This method, closely resembling the CAFE-solution of using a large amount of "regional airports", however would only be possible either in cities with little traffic, or in cities where the roads have been made car-free (as proposed in this article). Given that a larger amount of people would be able to use the road system (using smaller vehicles), this would be the best option, and a AT autogiro is thus best not created. This because, although new options would be possible (such as landing on rooftops), bad city (or urban) design is then actually supported. Also, despite that an autogiro is a lot more cost-effective than other VTOL-designs such as helicopters, the efficiency is still less than that of airplanes (with a long wingspan/low-power engine).

[edit] Autonomous flight

Paparazzi (http://paparazzi.enac.fr/wiki/Main_Page) and the ArduPilot (www.diydrones.com) are both open-source systems capable of autonomous flight and give aircraft the capability to fly a preprogrammed route. Such a system could possibly be introduced to the freighter or microlight aircraft to eliminate the need of a pilot, and to increase capacity, increase safety, ... Besides open-source software, commercial software also exist such as Micropilot not sure though whether this software provides any benefits (ie use of cruising speeds, compensation for wind, possibility for use of sensors to detect obstacles, exection of a specific task upon reaching a destination, ...)^[12]

[edit] Possible cooperators

• Air First Aid, cargo transport by microlight

[edit] References