The CIAM branch of FAI revised the rules governing what constitutes a model aircraft in 1947, at that time Wmax was revised upward to 5kg, it hasn't changed since and I haven't been able to find reasoning for it in online FAI records. I do know they recently created an exemption to allow IMAC style competition to be governed by CIAM even though weights there are well over 10kg. <br>
<br>In short, the FAI limit of 5kg hasn't changed in 65 years, the reasons for the limit are almost certainly obsolete (servo power, radio system reliability and capability, maximum speed (which would argue for a reduction in weight if it were the reason based on E=mv^2), power system capability, construction techniques and capability (CNC laser cutting, etc). But FAI is even more conservative than the crowd on this list!<br>
<br>Peter+<br><br>On Sunday, March 11, 2012, John Fuqua <<a href="mailto:johnfuqua@embarqmail.com">johnfuqua@embarqmail.com</a>> wrote:<br>> You will have to find someone who flew FAI from the sixties to answer that<br>
> question. I have been in pattern since the late seventies and its always<br>> been 5kg/11lbs. Have no clue how FAI came to that weight.<br>><br>> -----Original Message-----<br>> From: <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>
> [mailto:<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a>] On Behalf Of<br>> <a href="mailto:vicenterc@comcast.net">vicenterc@comcast.net</a><br>> Sent: Sunday, March 11, 2012 6:20 PM<br>
> To: General pattern discussion<br>> Subject: Re: [NSRCA-discussion] Rules Proposals<br>><br>> Plus one here. I am also 110% against any weight increase.<br>><br>> Question: as David L. explained is important to study the history of how we<br>
> decided the 5 kg limit. Can we elaborate on details of this history? I<br>> would like to know.<br>><br>> Best regards,<br>><br>> Vicente "Vince" Bortone<br>> Sent via BlackBerry by AT&T<br>
><br>> -----Original Message-----<br>> From: "Dave Harmon" <<a href="mailto:k6xyz@sbcglobal.net">k6xyz@sbcglobal.net</a>><br>> Sender: <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>
> Date: Sun, 11 Mar 2012 17:55:52<br>> To: 'General pattern discussion'<<a href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>><br>> Reply-To: General pattern discussion <<a href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>><br>
> Subject: Re: [NSRCA-discussion] Rules Proposals<br>><br>> _______________________________________________<br>> NSRCA-discussion mailing list<br>> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>
> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>> _______________________________________________<br>> NSRCA-discussion mailing list<br>
> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
><br>> _______________________________________________<br>> NSRCA-discussion mailing list<br>> <a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>> <a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
><br><br>-- <br><div>Director, Fixed Wing Flight Training</div><div>Santa Clara County Model Aircraft Skypark</div><img src="http://farm8.staticflickr.com/7163/6513778381_5569cc985d_m.jpg"><br><br>