Newman Airfoils
Peter Chapman
where they originate and how they have been used.
I came across them only once, mentioned briefly in some J. of Aircraft
paper. I think it also dealt with Gurney flaps. Apparently a Newman
airfoil consists of an uncambered 'foil with an elliptical (or
similar?) leading edge. From somewhere aft of the point of maximum
thickness, straight lines run at a tangent to the ellipse back to the
trailing edge point. Very simple.
I understand that this unsophisticated design has been used as a some
form of a reference standard in wind tunnel work. I found the shape
interesting because it is very similar to what has appeared on
Unlimited category aerobatic aircraft. I believe the Mudry CAP 21 may
have been the first, with an airfoil designed with the help of
Aerospatiale or some big name Frenchy company. Walter Extra's planes
copied the design or concept, as far as I can tell. I don't have notes
with me, but max. thickness for both lines of airfoils is well
forward, at perhaps 15% of chord. The Sukhoi Su-26 and similar also
makes use of such an airfoil, although the point of max. thickness is
further back (25%?). The Sukhoi airfoil may curve slightly inward as
it flows back to the trailing edge. Gord Price's Ultimate 10-300S
also used slab or 'snow cone' style airfoils.
About 5 years back I made up a few Newman sections and ran them
through Mark Drela's XFOIL airfoil analysis program. The sections
achieved some impressively high lift coefficients for uncambered
surfaces, although they were somewhat draggy. (However, predictions of
airfoil performance up near the stall may be less accurate.) The high
lift at the expense of drag may be an acceptable tradeoff for an
aerobatic monoplane.
As for other recent aerobatic airfoils, this is my understading:
- '88 world champion Henry Haigh used an airfoil on his Ratsrepus that
was created by Liebeck. The airfoil began as an 0012 and was designed
from there.
- John Roncz did the airfoil for the Edge wing, which has been available
for Laser-style monoplanes.
------------------------------------------------------------------------------
Peter Chapman
Management Sciences
U. of Waterloo, ON
(519) 885-1211 x3675
james r sonnenmeier
>Does anyone have information about Newman airfoils? I'm curious as to
>where they originate and how they have been used.
>
>I came across them only once, mentioned briefly in some J. of Aircraft
>paper. I think it also dealt with Gurney flaps. Apparently a Newman
>airfoil consists of an uncambered 'foil with an elliptical (or
>similar?) leading edge. From somewhere aft of the point of maximum
>thickness, straight lines run at a tangent to the ellipse back to the
>trailing edge point. Very simple.
A gentleman named Jef Raskin invented a similar series of airfoils
from a non-scientific point of view for acrobatic radio controlled
slope sailplanes. again he simply used an ellipse and tangent
straight lines to the trailing edge. I've written a small fortran code
to calculate the shapes of the Raskin airfoils for any thickness and
position of maximum thickness along the chord. I started to play with
XFOIL to analyze some specific shapes for Jef but never had the time
to finish the work.
I'm including the source code for anyone who is interested. eliminate
the graphics routine if you don't have DI3000. I also have a very
short article describing the equations if anyone is interested email
me.
---------------- included text starts here -------------------
program main
c
c=========================================================================
c
c Author: Jim Sonnenmeier j...@santa.eng.buffalo.edu
c For: Personal use
c Date: 11/93, modified 10/94
c UNIX Version: 1.0
c Files: wefoil.f
c Purpose:
c
c The compile line is, di3load wefoil.f -o wefoil with graphics
c or f77 wefoil.f -o wefoil without the graphics
c
c This program generates coordinates for the WE series
c of airfoils. Plots of the coordinates are also available
c using DI3000 graphics subroutines. Also output of the
c coordinates for use with plotfoil.
c
c
c The airfoils were invented by Jef Raskin for the ANABAT
c series of aerobatic slope sailplanes. Reference, SOARTECH 10
c copyright 1993 by Herk Stokely and Jef Raskin ras...@well.sf.ca.us
c
c==========================================================================
c
dimension x(61), y(2,61)
real thick, thkpos
character*30 name,name2
character*1 answer
c
c equation for the leading edge ellipse
c
f1(x) = (thick/thkpos)*sqrt(2.*thkpos*x-x**2)
c
c equation for the trailing straight line
c
f2(x) = y0*(1.-(x-x0)/(1.-x0))
c
nv = 61
499 format(1a1)
dx = 1./60
xi = 0.0
do 4 i= 1,61
x(i) = xi
xi = xi+dx
4 continue
write(unit=*,fmt=99)
99 format(/,
c ' This program calculates the WE series of airfoils.'/
c ' It writes the coordinates to an output file and '/
c ' has the option of producing graphical output of '/
c ' resulting airfoil.')
write(unit=*,fmt=100)
100 format(/,' Input the name of the airfoil : ',$)
read(unit=*,fmt='(a)') name
name2 = name//'.plt'
open(unit=1,file=name2,form='formatted',status='new')
4000 thkpos = 0.0
thick = 0.0
do 3 i = 1,61
y(1,i) = 0.0
y(2,i) = 0.0
3 continue
write(unit=*,fmt=101)
101 format(/,
c ' Input the position of maximum thickness of the airfoil'/
c ' as a percentage of the chord (10.0,20.0,30.0 etc...): ',$)
read(unit=*,fmt=*) thkpos
thkpos=thkpos/100.
write(unit=*,fmt=102)
102 format(/,
c ' Input the thickness of the airfoil'/
c ' as a percentage of the chord (8.0,10.0,15.0 etc...): ',$)
read(unit=*,fmt=*) thick
thick = thick/200.
x0 = thkpos/(1.-thkpos)
y0 = f1(x0)
do 10 i= 1,nv
if (x(i).lt.x0)then
y(1,i) = f1(x(i))
else
y(1,i) = f2(x(i))
endif
y(2,i) = -1.*y(1,i)
10 continue
y(1,61) = 0.0
y(2,61) = 0.0
write(unit=1,fmt=200) int(thkpos*100.),int(thick*200.)
c 200 format(/,' airfoil data for WE',2(I2))
200 format(/,' WE',2(I2))
c write(unit=1,fmt=202)
c 202 format(/,' x y(upper) y(lower)',/)
c
do 5 i= nv,1,-2
c do 5 i= nv,1,-1
c do 5 i= 1,nv
c write(unit=1,fmt=201) x(i) ,y(1,i), y(2,i)
c 201 format(3(5x,f8.3))
write(unit=1,fmt=201) x(i) ,y(1,i)
201 format(2(f10.5))
5 continue
c do 51 i = 2,nv
do 51 i = 3,nv,2
write(unit=1,fmt=201) x(i) ,y(2,i)
51 continue
c
write(unit=*,fmt=103)
103 format(/,' Do you want to see plots? [d: n] ',$)
read(unit=*,fmt=499) answer
if((answer.ne.'y').and.(answer.ne.'y')) go to 1000
call graph(x,y,thkpos,thick)
1000 write(unit=*,fmt=600)
600 format(/,' Run again? [d: n] ',$)
read(unit=*,fmt=499) answer
if((answer.eq.'y').or.(answer.eq.'y')) go to 4000
stop
end
c
c*** this routine plots the airfoil coordinate data using di-3000.
c
subroutine graph(x,y,c,t)
dimension x(61),y(2,61),dx(6),dy(3)
real c,t
character*3 lable
character*6 foil
real x,y
data dx /0.0,0.2,0.4,0.6,0.8,1.0/
data dy /0.2,0.0,0.2/
c
c initialize di-3000
c
call enttek()
call jbegin
call jdinit(1)
call jdevon(1)
call jaspek(1,ratio)
call jvspac(-1.,1.,-ratio,ratio)
call jvport(-.9,.9,-.9*ratio,.9*ratio)
c call jvspac(-1.0,1.0,-0.85,0.85)
fact = (1.4*2.*ratio)/4.
c call jwindo(-0.2,1.2,-0.595,0.595)
call jwindo(-0.2,1.2,-1.*fact,fact)
c
c draw grid and plot the airfoil data.
c
call jopen(1)
call jjust(1,1)
call jmove(0.0,-0.2)
call jdraw(0.0,0.2)
call jdraw(1.0,0.2)
call jdraw(1.0,-0.2)
call jdraw(0.0,-0.2)
do 10 i=1,9
call jrmove(0.1,0.0)
call jrdraw(0.0,0.4)
call jrmove(0.0,-0.4)
10 continue
call jmove(0.0,-0.2)
do 20 i2=1,3
call jrmove(0.0,0.1)
call jrdraw(1.0,0.0)
call jrmove(-1.0,0.0)
20 continue
call jmove(0.0,-0.25)
do 30 j=1,6
write(unit=lable,fmt=101) dx(j)
101 format(f3.1)
call j1text(3,lable)
call jrmove(0.2,0.0)
30 continue
call jmove(-0.1,-0.2)
do 40 j1=1,3
write(unit=lable,fmt=101) dx(j)
call j1text(3,lable)
call jrmove(0.0,0.2)
40 continue
call jmove(0.50,-0.35)
call j1text(3,3hx/c)
call jmove(-0.2,0.0)
call j1text(3,3hy/c)
c
call jmove(0.7,0.4)
write(unit=foil,fmt=200) int(c*100.),int(t*200.)
200 format('WE',2(I2))
call j1text(6,foil)
c
call jmove(0.0,0.0)
do 50 k=1,61
call jdraw(x(k),y(1,k))
50 continue
call jmove(0.0,0.0)
do 60 k1=1,61
call jdraw(x(k1),y(2,k1))
60 continue
call jclose
c
c plot a hardcopy, if desired, now.
c
read(unit=*,fmt='(a)')answer
call jdevof(1)
call jdend(1)
call jend
call exttek()
return
end
c
subroutine enttek()
character gs, etek*6
parameter (gs = char(29))
parameter (etek = char(27) // '[?38h')
write(unit=*, fmt=1) etek, gs
1 format('+',a,a)
return
end
c
subroutine exttek()
character xtek*9
parameter (xtek = char(24)//char(27)//char(3)//char(27)//'[?38l')
write(unit=*, fmt=1) xtek
1 format($,a,$)
return
end
c
--
James Sonnenmeier, PhD Work Phone: (716) 645-2593 x 2303
University at Buffalo
Dept of Mechanical and Aerospace Engineering
Buffalo, NY 14260 Office: 309 Jarvis Hall