The 11lb limit comes from the FAI limit for pattern of 2x2M max size & 5Kg max weight
Quite a few years ago there was also a 10cc (60) engine limit. There were calls at the time to have an unrestricted engine capacity limit to lower the cost of pattern as the 10cc engines were becoming quite specialised for pattern & therefore
expensive. If the engine size was unrestricted then cheaper but higher capacity engines could be used. Well engine capacity did become unrestricted, so did that lower the cost ? - NO it had the opposite effect and we got larger capacity
Specialised F3A engines that were even more expensive !!
IMO if the weight limit were increased then a similar effect would occur and cost would increase - I can imagine, for example, if a weight limit of 6Kg (13.2 lb) was allowed then we could get super “bloated” BiPlanes with full 2M wingspans and exotic/super expensive power systems to drag them around the sky....
Steve
I continue to play with gas engines for pattern and have to inform the uninitiated that this power source is perfectly viable for this sport. Gas engines and pipes are comparatively inexpensive to own, operate and maintain. The OS GT 33 on pipe and the DA35 on pipe put out just as much useful power as the YS 185. Just started flying my Griffin converted to gas (OS GT33, ESComposites 40G pipe) which weighs about 155 ounces. Performance to bern.
Should the powers that be bump up the weight limit to 5.5 or even 6 kilos, either the valley view or DLE 40 cc twin on pipes will easily haul the mail. And these engines are so light there is little reason to be heavier than 5.5 kilos. On pipe, output is close to 5 hp and will turn 22x8 or 9". Neither of these power plants are expensive and are simple to operate and maintain. Of course, there are those that just love to spend their money....okay with me.