high stabs? full scale airfoils?

[bodywerks]

I believe there is also a minimum height that wings and stabs need to be above the ground on full scale planes so that they can clear taxi lights at airports and such, which may be why the stabs are higher.

[Bam Bam]

now that there is something i woulnd never have thought of! but it does make sense!

[bodywerks]

it was something I heard from a pilot - call it a rumor for now.

[Ian]

	Quote: Originally Posted by Mithrandir
	I had a Jekyl years ago and I kinda did an anhydral thing to the stab... it was popular back in the dark ages... (1970's and 80's)... anyway... the plane was the only plane I ever had that truly had ZERO pitch coupling.... it had adverse roll coupling... but just a little baby amount.... and being a pattern plane, I never got it to like 45 degrees of beta.... (Like my avatar)... so who knows what would happen at that extreme angle...

There was a design that was floating about over 6 years ago in the UK called the "Capiche 140ex". It was a 78" span model, 78" long, and weight was between 9.5lbs and 11lbs. it was 100% true, a perfect freestyle machine. Zero coupling, nothing, any speed, any AoA, knife edge, harriers, there wasnt a single problem with it




Wing and tail dead in line, motor higher, but a Yak 55 style of canopy. the interesting thing also is the wing and the tail are very low on the fuselage side area, certainly not central

Think left stick only knife edge square loops

[Bam Bam]

Never seen that plane before. looks interesting.

[Ian]

it was a short kit, not many made, in the UK only. Weston UK have released a ARF, but its about 2lbs heavier on average. Aerodynamically the model is fantastic, the right amount of drag, the right positioned surfaces etc. Its quite odd to see the tail and wing so low though

[ndb8fxe]

	Quote: Originally Posted by bodywerks
	I believe there is also a minimum height that wings and stabs need to be above the ground on full scale planes so that they can clear taxi lights at airports and such, which may be why the stabs are higher.

However, I don't think it would be good practice to be running over taxi lights so that they would hit the tail. You are supposed to taxi between the lights unless there are centerline lights which would be embedded.

[slothead]

Ok so where does the MX2 fit into the mix of all these planes.
and who makes a model of it.

Slothead

[Sukhoikid]

I cant wait to take my Aerodynamic classes in school. Should be fun to learn! I am def going to be asking questions regarding the models!

[wingwall]

40% to 50% scale planes should be getting pretty close to the same Reynolds Numbers, so the airfoils should also be getting closer to performing the same. Without a human aboard though, wing loading is much lower. The model should perform better.

When you are talking about coupling, I believe most are referring to performance in knife edge, or near knife edge, flight. Don't forget about vertical position of CG. All forces are acting on the CG, or center of mass, and the resisting forces of drag. The (necessary) landing gear is hanging out there below and forward of the CG, and it is usually a significant weight at a large moment arm. In knife edge it makes sense to have a high rudder. That is, center of lift to the high side of the fuselage, to provide the force necessary to hold the gear from rotating the plane out of the knife edge.

I believe in most cases the vertical position of the CG and dihedral of the wing is what effects the "roll" out in knife edge. The vertical position of the stab and CG effects the "pitch" out of knife edge. In aerobatics, to make things less complicated for the pilot, it's all about finding a configuation in which application of rudder, or other surface, has a pure action. For example, rudder just creates yaw. No roll. No pitch. Athough, good pilots learn the actions of the inputs and can compensate. Whether they like it or not is another story.