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Phoenix
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Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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 Posted: Sat Mar 05, 2011 1:48 pm Post subject: Looking for math/physics FORMULAE PERTAINING to HG |
 #1 |
If you have any resources for me to check out along these lines, let me
know! Calculus O.K.
Looking for all manner of stuff, wing loading, g force, wing dynamics, structural.
Please no programs, encyclopedias, joke. Just the equations, thanks!
Last edited by Phoenix on Tue Mar 08, 2011 5:29 am; edited 1 time in total |
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mlbco
3 thumbs up
Joined: 12 May 2008
Posts: 517
Location: Sunnyvale, CA
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| Posted: Sat Mar 05, 2011 4:45 pm Post subject: |
#2 |
Here's some Matlab code to estimate a glider's polar.
Steve
%Polar Estimation MATLAB Code
%SJM 3-5-11
close all;clear all;
torad=pi/180.;
d2r=torad;
grav=32.174;
%-------------------------------------
%T2C
weight=70.0+200; %Gross weight (lb)
bref=33.5; %wing span (ft)
sref=154.0;%wing area (ft^2)
fo=1.75;%Non lifting drag area (ft^2) This accounts for pilot, downtubes, rigging, instruments, etc.
clmax=1.3; %Stall CL
clmin=0.2; %dive CL
cdo=.01; %zero lift drag for the wing section
cd2=.005; %lift dependent viscous drag for the wing section
ro=0.00237; % air density (slug/ft^3)
e=0.9; % span efficiency factor (0<e<1)
bank=0.0*torad; %bank angle (deg) (use this to estimate polar in turing flight i.e. thermalling)
%-------------------------------------
%------------------------------------------
ar=bref*bref/sref;
num=100;
dcl=clmax/num;
for i=1:num
cl=clmax-dcl*(i-1);
if(cl>clmin)
cd=fo/sref+cdo+cl*cl*(cd2+1./(pi*ar*e)); %drag coeff
vo(i)=sqrt(2.*weight/(ro*cl*sref*cos(bank)));%Airspeed at trim CL (ft/sec)
drag=0.5*ro*vo(i)*vo(i)*cd*sref; %Drag (lb)
vv(i)=(-drag*vo(i)/weight);%sink rate (ft/sec)
radius(i)=1e6;
if(bank>0)
radius(i)=vo(i)*vo(i)/(grav*tan(bank));%Turn Radius (ft)
end;
phi(i)=bank/torad;% Bank angle(deg)
ld(i)=vo(i)/-vv(i);%L/D w.r.t. air
gam(i)=atan(1/ld(i))/d2r; %Glide angle (deg)
%ld2(i)=cl*cos(bank)/cd;
end;
end;
figure(1);plot(vo/1.467,ld,'-b');zoom on;grid on; %L/D vs airspeed (mph)
figure(2);plot(vo/1.467,60*vv,'-b');zoom on;grid on; %Sink rate (fpm) vs airspeed (ft/sec) |
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AIRTHUG
3 thumbs up
Joined: 09 Aug 2007
Posts: 6159
Location: Point of the Mountain, Draper, UT
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SeeMarkFly
2 thumbs up
Joined: 24 Mar 2008
Posts: 1681
Location: Lakeview Oregon
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| Posted: Sat Mar 05, 2011 5:37 pm Post subject: |
#4 |
| AIRTHUG wrote: |
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http://www.khanacademy.org |
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Phoenix
2 thumbs up
Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 5:45 pm Post subject: |
#5 |
No mat lab. But I do have mathematica circa 2006. Also mathcad circa 2001.
Not into programing much, just the equations. |
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Phoenix
2 thumbs up
Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 5:50 pm Post subject: |
#6 |
| SeeMarkFly wrote: |
| AIRTHUG wrote: |
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http://www.khanacademy.org |
NICE resource, but no time to parse through it all! |
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st1lgar
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Joined: 25 Jan 2011
Posts: 343
Location: Oak Ridges, ON
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| Posted: Sat Mar 05, 2011 6:09 pm Post subject: |
#7 |
now having the polars you can calc mccready...
look here 
http://faculty.chicagobooth.edu/john.cochrane/research/Papers/newmcred.pdf
_________________
"Men were not meant to leave the Earth. Spend too much time in the clouds and you never want to come back down again. I know skinchangers who've tried hawks, owls, ravens. Even in their own skins, they sit moony, staring up at the bloody blue" -- Hoggon
George R.R. Martin |
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Phoenix
2 thumbs up
Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 7:07 pm Post subject: |
#8 |
now having the polars???? I can not decode MATLAB! I don't do programing!!!
I will read the mccready article though.
Just asking for formulae that apply to HG, (from simple stuff to polars) not the entire volume of mathematics from pythagoras to Andrew Wiles, now sorry I asked!  |
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Phoenix
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Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 10:30 pm Post subject: |
#9 |
deleted
Last edited by Phoenix on Sun Mar 06, 2011 1:40 am; edited 1 time in total |
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Phoenix
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Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 10:30 pm Post subject: |
#10 |
Deleted
Last edited by Phoenix on Sun Mar 06, 2011 1:42 am; edited 1 time in total |
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Phoenix
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Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 10:30 pm Post subject: |
#11 |
Deleted-caught by the server down
Last edited by Phoenix on Sun Mar 06, 2011 1:44 am; edited 3 times in total |
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Phoenix
2 thumbs up
Joined: 21 Dec 2010
Posts: 1414
Location: USA Reg 5
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| Posted: Sat Mar 05, 2011 10:36 pm Post subject: |
#12 |
Just skimming the article, looks like something interesting to try and wrap my mind around! 
Thanks, but I'm not that much of an XC guy. |
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rongleason
3 thumbs up
Joined: 10 Dec 2006
Posts: 132
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| Posted: Sun Mar 06, 2011 7:09 am Post subject: formula |
#13 |
checking account = x
start HG
buy equipment, buy new vehicle, convince the SO to camp and drive
checking account now = x-(HG equip - vehicle - gifts to keep SO happy) + 50% of usual paycheck due to number of sick days taken
long HG trips, quit job, SO leaves etc
checking account has been closed and live off the cash in the wallet |
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