forces of flight?

[flyinazn10]

i am currently building a plane and about ready to glass the airframe. when I do, im a bit curious as to where the forces of flight will be most stressed, especially the fuse. when in normal flight/high G maneuvers (pulling up at high speeds ect), is the fuse stressed, or is the stress put on the wings? of course by stressed i mean should I be sure to reinforce it securely or can I save a bit of weight and time with it?

[Sparky Paul]

On the fuselage, any place there's a opening and a load carrying structure in that opening, like the wing, it's a good idea to pay some attention to getting loads around the opening.
Where there's parts sticking out, like gear legs, the leverage these can exert on the fuselage should be considered.
Any substantial part.. motor, battery, servo, will resist changing its direction by adding a load to the structure that supports it, in manuvering flight.
Adequate bracing for all this stuff isn't difficult or heavy to install, just follow common practices.

[vintage1]

I've never seen a fuselage break in flight, but plenty on landing..

A hard landing can put several times the models weight in terms of peak loading into the areas connecting the undercarriage, wing, motor and pack. I tend to tie these all in to a fairly substantial single structure.

The other weak place in many of my models is immediately behind this structure: there is a stress conecntration as the tail is generally built light, and often snaps where the fuselage rear meets the main load carrying section.

[Ollie]

Good stuff to read:
http://www.djaerotech.com/dj_askjd/dj_questions/nylon.html
http://www.djaerotech.com/dj_askjd/dj_questions/fuse.html

From Dr. Mark Drela:
"You can pretend the V-tail is a little wing,
with its V dihedral removed. Instead of the
full design winch load force, scale it down
by the tail/wing area ratio, and also by the
tail/wing CLmax ratio. e.g. say your tail area
is 15% (or whatever) of the wing area, and the
flying stab's CLmax I'd say is about 60% as big
as that of your flapped wing. When the wing sees
the max design winch load of 150lb (or whatever)
at some high speed, the biggest equivalent
load the tail can possibly see is about

F = 150lb x 15% x 60% = 13.5 lb

This tail F value, and the tail span and other
parameters give the necessary joiner rod radius.

- Mark"

[pmackenzie]

In a high G turn the motor, battery and all the heavy parts want to leave via the bottom of the plane.
The wing wants to pull itself off of the fuselage, and the tail will probably be pushing downwards both from it's weight and the downward force of the lift it is generating.
The highest stresses by far are in the main spar of the wing.
Pat MacKenzie

[raptor22]

Nick: don't worry about it...its called a leadsled for a reason. Make a beefy spar, and pile material on there until you run out.....

You WANT it pretty heavy. Your biggest forces will just be from landing that thing at laguna without breaking it.

--Alex

[Hasina75]

There are four forces that affect an aircraft in flight: thrust, drag, lift, and weight.
Thrust is the opposite of drag while lift is the opposite of weight. The wing that supports the weight of the plane generates lift as long as the airplane flies above its stall speed. Therefore, the main wing should be reinforced.