Motorised:

Thermal gliders:

Such a glider needs to have a large speedrange. Slow speeds are needed inside the thermals and higher speeds are needed to get as fast as possible from one thermal to another. Other demands are not known to me yet.

Rigde gliders:

I heared that these gliders need to "shave" (flying from left to right and back again) a rigde. They fly mostly into the wind at a angle (wind in their sides). From this point I think that a rigde glider needs to be very stable, even autostable if possible. They fly most of the times "crosswinds" (wind in the sides) and they can be hit by a ridge-wind-gust. Forward sweep doesn't seem to be the ideal thing here unless you have a very large tail to react quickly. I have no idea if there are any speed demands. But like I said: gliders are not a speciality.

Motorgliders:

Motorgliders have a engine to get them in the air. And that is all the engine has to do. So you don't need a large engine as in a ultra light. There are some known models who have the possibility to restart their engines in the air. That would be nice, but not necessary in a basic model. Restarting a engine requires a electrical starter and a battery. They sound like a lot of weight to me. Gliders have mostly a good glideratio. The better the glideratio and the lower the weight, the smaller a engine has to be. So here again we see that the engine may be smaller than a ultra light. Most ultra lights have a glideratio like a brick... Althought there is a good evolution in that area.

Ultra lights:

Ultra lights have certain restrictions by law. Most countries have different restrictions. So you need to contact your local department of aviation to be sure to have the correct list.

Always keep in mind that this sector is mostly used by persons without the means to buy a sportplane or without the will to complete a schooling to become a authorised pilot (ultra light-pilots don't need a pilot license like the pilots of larger sportcategories, they do need a (less expensive) schooling in a ultra light club). What do we want to make clear: don't make your design to expensive. What would you choose if you had the money, a tiny ultra light or a small sportairplane at the same cost? My choice is quickly made.

So no need to make retractable landinggear, fit in a megabaster or a ILS-module. Just the basics! A closed cockpit should be the maximum.

Other sportscategories:

Every categorie has his typical restrictions by law. Like with the ultralights we advise you to contact your local department of aviation to get the correct list of restrictions. Since there are a lot of categories I will not list them (if someone knows a site where you can find this info. We will place a link)

Larger airplanes:

I don't think that a employee of Boeing or Northrop or any other large firm will need to be explained what a large aircraft has to do. So I leave this section untouched. I only will give you some quotes.