As past scale chairman of MAAC, a scale competitor and part of the committee that put on the FAI 2002 World Scale Championships held in Canada I can tell you that there is no definitive speed as per prototype used in judging in scale competition. I will attempt to give some insight into why in a bit.



When someone inquires about 1/4, 1/8, 1/6 etc. scale I explain that it’s not technically correct. Scale is always expressed as a ratio. Take a look at most model kits and you will see 1:4, 1:3 even 1:3.75 etc. The easy explanation is the number on the left of the colon is the dimension on the model and the on the right tells you how many times bigger it is on the full size.



Now as to scale speed. Its one of the most argued points of scale competition. There is no formula that works scaling down speed mathematically. Landing speeds and takeoff speeds are prime examples. Take the early aircraft where max speed was 80 or under. That would mean a 1:4 scale would be expected to fly max speed around 20 lands and take off somewhat less than that. A 1:6 scale around what 15 max and somewhat less for landing and take off. No competition I know of has ever measured actual speed as a judgement point in scale. They judge and use their perception called realism in flight and there are actually points given for this. What the judges expect to see from the model being showcased.