modified January 17, 2005 by Luke Grahame
-Material Density
-Material Density
-Material Skin (Sheet) Thickness
-Material Density
-Linear Material Density
http://www.modelflight.com/weight.html
Appromimate Linear Density for 2oz/yd^2 Fiberglass
Appromimate Linear Density for 2 Layer Buildup of 2oz/yd^2 Fiberglass
Appromimate Linear Density for 2 Layer Buildup of 10.5oz/yd^2 CarbonFiber
Max normal load factor
Typical Value in Raymer (11.11) pg. 289
Density of landing gear material
Density of tire material
-Approximate Dynamic Loading applied to each arm of the landing gear.
-Orientation angle main gear forms with horizontal axis.
-Length of main gear strut.
CALCULATED STROKE
Reference FAR 23.473(d) FAA typical values: 7-10ft/s
radius of wheel
rolling radius of tire, typical value
Shock Absorbing Effieciency
Tire Absorbing Efficiency
Stroke of Tire
Assuming wheel does not account for any delfection
Length changed to allow a positive margin of safety for bending stress
STEEL RECTANGULAR LANDING GEAR
GRAPHLITE RECTANGULAR LANDING GEAR
GRAPHLITE TUBE LANDING GEAR
-Modulus of Elasticity
Source: Geometry. See Fig. 11.11, p.289 - Raymer
Inertia is terrible for a tube
-Width of main gear cross section
Assuming square cross section
Calculation of Member Moments and Stress
Max Bending Moment of each side of Gear
Max Axial Load on each side of the Gear
Margin of Safety for Bending Stress in the Main Landing Gear
Distance to mid fiber
Max stress on gear
-Yield Stress for Considered Material
Margin of Safety for Shear Stress in the Main Landing Gear
Weight of Landing Gear:
Elliptical Chord Distribution:
Reference Raymer (14.9) pg. 413
Trapezoidal Chord Distribution:
-defined in layout section
Schrenk's Approximation:
Normalization to Load Distribution:
Shear Distribution
Moment Distribution
Bending Stress at Outer Fiber
Inertia of I-Beam
Reference http://www.marskeflyingwings.com/carbonrod_p2.html
Maximum Spar Thicknesses
Minimum margin between spar and airfoil skin
Maximum Thickness on the center section
Maximum Thickness on the outer section
Max allowable stress along span
Max compressive allowable stress along span
Graphlite Rod Compressive Stress
Reference http://www.continuo.com/marske/ARTICLES/Carbon%20rods/carbon.htm
Calculated stress along span
Max Shear allowable along span
Fiberglass
Reference Raymer pg.443
Calculated shear stress along span
Normalized Loading Distributions Based on Monks Approximation:
Display of Spanwise Properties:
.
Global Assumptions:
1.) Evenly Distributed Density
2.) 2-D Analysis Due to Symmetry
Main Components:
1.) Engine
2.) Fuselage
3.) Main Wing
4.) Vertical Tail
5.) Landing Gear
6.) Payload
7.) Batteries
8.) Servos
9.) Fuel Tank
10.) Horizontal Tail
Assumptions:
X-Location:
Assumptions:
-Density of wing tube spar material
-Linear density of wing skin material
Rib Properties:
-Rib thickness
Density of Spyder Foam
-Rib Density
Density of EPP Foam
Foam Wing Mass Approximation
Weight of Monokote Skin
Weight of Foam Core
Weight of Ribs
Weight of Skin
Weight of Front Spar
Weight of Front Foam Web
Weight of Rear Spar
Weight of Rear Web
Accounting for unforseen weight
Initialize first section of Mass array:
Semimonocoque Structure Wing Mass Approximation:
Assumptions:
-Density of wing skin material
-Thickness of skin of fuselage
-Density of wing bulkhead material
-Thickness of fuselage rib material
-Density of wing rib material
-Area of Stringer, based on wing spar area
Original Fuselage Weight Equation (Before Tapered Tail Section was Removed)
Weight of Fuselage Skin
Weight of Bulkheads
Weight of Stringers
Total Fuselage Weight
Fuselage CG Calculation
Assumptions:
-Approximation of local C.G. for horizontal tail
-Density of horizontal tail spar
-Thickness of horizontal tail rib
-Horizontal Tail linear skin density
Weight of Horizontal Tail Skin
Weight of Ribs
Weight of Foam Core
Weight of Spar
Weight of Skin
Semimonocoque Horizontal Tail Mass Approximation
Foam Horizontal Tail Mass Approximation
Assumptions:
-Thickness of vertical tail rib
-Density of vertical tail spar material
-Vertical Tail linear skin density
-Vertical rib density
Weight of Monokote Skin
Weight of Ribs
Weight of Foam Core
Weight of Skin
Weight of Spar
Semimonocoque Vertical Tail Mass Approximation
Foam Vertical Tail Mass Approximation
Assumptions:
Assumptions:
-Engine
-Fuel Tank
-Battery
-Nose Gear
Nose Servo
Assumptions:
Establish Initial Location of Payload C.G.
X-Location:
-Payload location
Payload Weight:
-Payload weight
Calculated distance forward of main wing m.a.c. quarter chord resultant local C.G. resides:
-Set max distance engine subsystem cg can be moved forward from main wing 1/4 mac
-CG location of the Fwd. Engine subsystem
Potentially redefine payload cg if global cg needs to be moved back to wing quarter chord:
Change of CG location with change in payload weight.
*Note: Negative Global CG Positioning Indicates Position
Forward of Quarter-Chord of Main Wing.
Engine
Nose Landing Gear
Fuel Tank
Batteries
Payload
Main Landing Gear
Receiver
Main Wing Servo's (2)
Main Wing
Empty CG
Fuselage
Total CG
Vertical Tail
Horizontal Tail
Tail Servo's (2)
.
.
Approximate Calculation
Moment of Inertia for Wing (1)
Moment of Inertia for Horizontal Tail (2)
Moment of Inertia for Vertical Tail (3)
Moment of Inertia for Fuselage (4)
Change CG location
Moment of Inertia for Engine (5)
Moment of Inertia for Fuel Tank (6)
Moment of Inertia for Battery (7)
Moment of Inertia for Main Landing Gear (8)
Moment of Inertia for Nose Gear (9)
Moment of Inertia for Wing Servos (10)
Moment of Inertia for Tail Servos (11)
Moment of Inertia for Receiver (12)
Airplanes Total Mass Moment of Inertia