Model Airplane dimensions

Have been finding a bit of inconsistancy is how model airplane overall dimensions are reported.

For wingspan, some cite the actual wing as constructed. Whereas others measure off the flat lengths shown on the plan. This would not be a quibble, but some of the old timers had very big dihedrals and this can easily alter the dimension by and inch or more.

Second, I find the fuselage length figures at variance. Usually it is from the most extreme curve of the rudder forward to ? Sometimes they measure tot eh nose to teh fuselage and other times it is the thrust washer on the engine.

Third, Height is most often at reat to the top of the rudder. However, I have found that on large high wing A/C the wingtips can actually be about the rudder tip.


Which system do you use? The A.M.A. outlines the measurements pretty heavily for rubber powered A/C, but not for powered flight.


Wm.

From what I can remember from my air force days is that we would measure wingspan from the wingtip to opposite wingtip in a straight level line. Height of aircraft was measured from the ground to the tallest point of aircraft, which does not necassarily mean the rudder. Fuselage length was measured from the forward most point of the aircraft to the aft most point of the aircraft. Maybe someone else will have other opinions.

Other than to meet competition rules, which are usually pretty clearly defined, there are no really critical calculations utilizing the overall dimensions. Therefore it doesn’t make much difference where you take the measurements as long as you are consistent.

There are no rules for this, even in full size-aircraft... it just makes comparing aircraft a painful experience.

Ken - [link=http://www.litkoaero.com]www.litkoaero.com[/link]
Litko Aerosystems, Inc.