Jan 17, 2013, 11:01 PM Mark Harrison USA, CA, Piedmont Joined Jun 2010 2,576 Posts Discussion calculations Given a prop length, prop pitch, and rotation speed (rpm), what are the formulas to calculate the theoretical - airspeed - volume of air - thrust
 Jan 18, 2013, 02:42 AM Registered User Staffs, UK Joined Nov 2003 12,226 Posts http://www.mh-aerotools.de/airfoils/index.htm Look under "Propellers". Steve
 Jan 18, 2013, 06:00 AM Registered User Commerce Township, MI Joined Aug 2001 5,079 Posts Another good source here: http://aircraft-world.com/prod_datas...p-proptalk.htm
 Jan 18, 2013, 12:54 PM Jack USA, ME, Ellsworth Joined May 2008 19,254 Posts The Powerplant calculators here will give most the useful info you're looking for: http://2bfly.com/tools/ And if you are looking for info on specific motors with various props or specific props with various motors, the info at flybrushless.com is hard to beat: http://www.flybrushless.com/ Jack
 Jan 19, 2013, 08:40 AM Registered User Germany, lake of constance Joined Oct 2010 409 Posts Another useful report (see attached file), but sorry in german language. May use the google translater: http://translate.google.com/ I have written a propeller tcl script based on the document from Helmut Schenk. Code: ```# Michael Schulz 21.01.2012 proc calculate {} { global Hz Dz np pin vp fp Prop N100 set Kp 100.0 set H [expr \$Hz*2.54/100.0] set D [expr \$Dz*2.54/100.0] if {(\$Prop == "APC")} {set Cp [expr 0.0856*(\$H/\$D) - 0.0091]} if {(\$Prop == "AERONOUT-CAM")} {set Cp [expr 0.0833*(\$H/\$D) - 0.0116]} if {(\$Prop == "Speed-Prop")} {set Cp [expr 0.116*pow((\$H/\$D),2)- 0.066*(\$H/\$D) + 0.0467]} set n100 [expr 60*pow((\$Kp/(\$Cp*pow(\$D,5)*1.225)),0.333)] set n100 [format %1.0f \$n100] \$N100 delete 0 100 ; # \$N100 insert 0 \$n100 set Pin [expr pow((\$np*1.0/\$n100),3)*\$Kp] set Pin [format %1.0f \$Pin] \$pin delete 0 100; \$pin insert 0 \$Pin set Vp [expr \$H*\$np/60.0] set Vp [format %1.1f \$Vp] \$vp delete 0 100 ; # \$vp insert 0 \$Vp set F [expr 0.785 * pow(\$D,2)] set S1 [expr 0.55*\$Pin] set S2 [expr pow(\$S1,2)] set S3 [expr (2 * 1.225 * \$F * \$S2)] set Fp [expr pow(\$S3,0.333)/9.81] set Fp [format %1.2f \$Fp] \$fp delete 0 100 ; # \$fp insert 0 \$Fp set SD [expr \$H/\$D] if {(\$SD >= 0.9) & (\$Prop != "Speed-Prop")} {tk_messageBox -icon error -message "Use Prop Style -> Speed Prop !"} } proc gui {} { global Hz Dz np pin vp fp Prop N100 wm minsize . 285 330 wm title . "Propeller V1.0 M.Schulz" set a [labelframe .a -bd 3] set m1 [frame .a.m1] set f0 [frame \$m1.f0] set lf0 [label \$f0.lf0 -text "Prop Style: " -font {Arial 10 bold }] tk_optionMenu \$f0.1 Prop AERONOUT-CAM APC Speed-Prop pack \$lf0 -side left pack \$f0.1 -side right pack \$f0 pack \$m1 -fill x -pady 6 set a1 [frame \$a.a1] set al [label \$a1.l -text {Prop Diameter ["] } -font {Arial 11 }] set ae1 [entry \$a1.e -width 6 -justify right -textvariable Dz -font {Arial 11 }] pack \$al -side left pack \$ae1 -side right pack \$a1 -fill x -pady 5 set a2 [frame \$a.a2] set al [label \$a2.l -text {Prop Pitch ["] } -font {Arial 11 }] set ae2 [entry \$a2.e -width 6 -justify right -textvariable Hz -font {Arial 11 }] pack \$al -side left pack \$ae2 -side right pack \$a2 -fill x -pady 5 set a3 [frame \$a.a3] set al [label \$a3.l -text {Prop speed [rpm] } -font {Arial 11 }] set ae3 [entry \$a3.e -width 6 -justify right -textvariable np -font {Arial 11 }] pack \$al -side left pack \$ae3 -side right pack \$a3 -fill x -pady 5 pack \$a -fill y -pady 12 set b [labelframe .b -bd 3] set b1 [frame \$b.b1] set bl [label \$b1.l -text {n100 [rpm] } -font {Arial 11 }] set N100 [entry \$b1.e -width 6 -justify right -font {Arial 11 }] pack \$bl -side left pack \$N100 -side right pack \$b1 -fill x -pady 5 set b2 [frame \$b.b2] set bl [label \$b2.l -text {Prop Input Power [W] } -font {Arial 11 }] set pin [entry \$b2.e -width 6 -justify right -font {Arial 11 }] pack \$bl -side left pack \$pin -side right pack \$b2 -fill x -pady 5 set b3 [frame \$b.b3] set bl [label \$b3.l -text {Static Prop Thrust [kg]} -font {Arial 11 }] set fp [entry \$b3.e -width 6 -justify right -font {Arial 11 }] pack \$bl -side left pack \$fp -side right pack \$b3 -fill x -pady 5 set b4 [frame \$b.b4] set bl [label \$b4.l -text {Pitch Speed [m/s]} -font {Arial 11 }] set vp [entry \$b4.e -width 6 -justify right -font {Arial 11 }] pack \$bl -side left pack \$vp -side right pack \$b4 -fill x -pady 5 pack \$b -fill y -pady 20 set bu [labelframe .bu] button \$bu.1 -text "Calc" -command {calculate} -font {Arial 11 bold } -bd 3 pack \$bu.1 pack \$bu } ########################## Main ############################################### set ignore [catch {eval {wm iconbitmap . -default [file join snoopy.ico]}}] global Dz Hz np set Dz 14; set Hz 8; set np 5500; gui``` Download of the Propeller program: http://snoopy-schulz.square7.ch/Propeller.exe Last edited by snoopy_schulz; Jan 19, 2013 at 08:56 AM. Reason: typo
 Jan 22, 2013, 01:10 PM Mark Harrison USA, CA, Piedmont Joined Jun 2010 2,576 Posts These all look like great resources. Thanks guys!!