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Ascent 450 Brushless PNP by Eflite
http://www.horizonhobby.com/Products...700#quickSpecs Max. wt. 19 oz. Wing area: 330 sq.in. CWL 5.48 oz./cu.ft. CWL Level 3 low end Extra 260 3D 480 ARF by Eflite http://www.horizonhobby.com/Products...475#quickSpecs Max. wt. 29 oz. Wing Area: 375 sq.in. CWL 6.90 oz./cu.ft. CWL Level 3 high end Typical 3D airframes have a lot more in common with powered gliders than they do with prop powered planes that fly on the wing. 35% Extra 260 ARF (2 Boxes) by Hangar 9 http://www.horizonhobby.com/Products...000#quickSpecs Max. wt. 30 lb. (480 oz.) Wing Area: 2003 sq.ft. CWL 9.25 oz./cu.ft. CWL Level 4 high end CWL Excel worksheet at http://homepage.mac.com/kmyersefo/M1...cnewtheory.xls Level 1 CWL up to 3 oz./cu.ft. Level 2 CWL 3 oz./cu.ft. to 5 oz./cu.ft. Level 3 CWL 5 oz./cu.ft. to 7 oz./cu.ft. Level 4 CWL 7 oz./cu.ft. to 10 oz./cu.ft. Level 5 CWL 10 oz./cu.ft. to 13 oz./cu.ft. Level 6 CWL 13 oz./cu.ft. to 17 oz./cu.ft. Level 7 CWL 17+ oz./cu.ft. The spreadsheet clearly illustrates, with 100s of recorded real life examples, which types of planes are found in which Levels. 



Joined Mar 2009
11 Posts

What size prop do I need to use on an Eflite Power 90 running on 6s, 5000mha to obtain 1,100 Watts? Example 16x10 APC Electric. Called Horizon and they have nothing. Thanks for any help I can get to save buying $10 props and trying to find the right one.




Hi apucjames
You need a 18x8 APC E prop. Best regards Micha 







Quote:
There is no danger. I use a java script for the calculation, so your security software may issues a warning due to the java script. My drive calculator is only running with the windows internet explorer. With firefox it is not running. I have tried anything, but it dont works. Maybe something in my java script is not ok for other explorer? Best regards Micha 




Java Script of my drive calculator
Hi
Here is my java script. Maybe someone has an idea why it is not running with firefox. Best regards Micha Code:
<! Begin var list=0 var KennWerte=new Array(); var ke=0; var iL=0; var Rm=0; var ke1=0; var iL1=0; var Rm1=0; var etag=0; var u=0; var etag1=0; var ueb1=0; var nZ=0; var Raccu=0; var Rg=0; var KennWerteP=new Array(); var n100=0; var H=0; var D=0; var KennWerteA=new Array(); var u_accu=0; var Ri=0; function getRadios(what){ if(what.sel.checked) list=1.0 else list=0.0 } function DoCalc(form) { motor=form.m_type.options[form.m_type.selectedIndex].value; KennWerte=motor.split("/"); ke1=KennWerte[0]*1; iL1=KennWerte[1]*1; Rm1=KennWerte[2]*1; ueb1=KennWerte[3]*1 ;etag1=KennWerte[4]*1;Kflug=KennWerte[5]*1; nZ=eval(form.nZ.value); propeller=form.p_type.options[form.p_type.selectedIndex].valuep; KennWerteP=propeller.split("/"); n100=KennWerteP[0]*1; H=KennWerteP[1]*1; D=KennWerteP[2]*1; //document.write("Kp : " + Kp ) Akku=form.accu_type.options[form.accu_type.selectedIndex].value_accu; KennWerteA=Akku.split("/"); u_accu=KennWerteA[0]*1; Ri=KennWerteA[1]*1; // war Akku ausgewδhlt ? if (u_accu == 0) {alert("Please choose a accu!")} // is gearbox defined ? if (etag1 != 0) {etag = etag1} else {etag=eval(form.etag.value)} if (ueb1 != 0) {ueb = ueb1} else {ueb=eval(form.ueb.value)} // is motor defined ? if (ke1 != 0) {ke = ke1} else {ke = eval(form.ke.value)} if (Rm1 != 0) {Rm = Rm1} else {Rm = eval(form.Rm.value)} if (iL1 != 0) {iL = iL1} else {iL = eval(form.iL.value)} // check whether Gear, Motor and Prop changes have been made if (ueb == 0) {alert("Enter gear ratio: '1' for direct drive")} if (etag == 0) {alert("Enter gear efficiency: '1' for direct drive")} if (ke == 0) {alert("Enter rpm/V!")} if (iL == 0) {alert("Enter No load current !")} if (Rm == 0) {alert("Enter internal resistance!")} if (n100 == 0) {alert("Enter Prop!")} // update displayed characteristics form.ke.value=ke;form.iL.value=iL; form.Rm.value=Rm; form.etag.value=etag; form.ueb.value=ueb; // Start of the caculation // var Raccu=nZ*Ri; var Rg=Rm+Raccu+0.01; var U=nZ*u_accu; var Ke=1/ke; // V/rpm var Ishort=U/Rg; // blocking current // Prop speed var Kp=100 var ueb=1/ueb var RPMa=(Math.sqrt(Ke*Math.pow(n100,3)*U*(4*Ishort*Kp*Math.pow(Rg,3)*Math.pow(ueb,3)*(IshortiL)+Math.pow(Ke,3)*Math.pow(n100,3)*U)) Math.pow(Ke,2)*Math.pow(n100,3)*U)/(2*Ishort*Kp*Math.pow(Rg,2)*Math.pow(ueb,3)/Math.pow(etag,0.333)) // efficiency and shaft power var Pw=Math.pow(RPMa*ueb/n100,3)*100; // shaft power var Im=(IshortKe*RPMa/Rg)///Motor current var Uk=U(Raccu+0.01)*Im // terminal voltage ot the motor //var etam=(1Im/(Uk/Rm))*(1iL/Im); // Max efficiency motor var etam=Pw/Uk/Im; // efficiency Motor incl. gearbox var etamg =Pw/U/Im; // totall efficiency var Pv=Rm*Im*Im // Pv of motor coil var nm=RPMa; // Motor speed var Vp=H*(2.54/100)*ueb*RPMa/60 // prop pitch speed var HD = H/D var J =0.2421 * Math.pow(HD,3) + 0.439 * HD + 0.1546 var Vf = J * ueb * RPMa * D * 0.0254 / 60 var Dm = D * 2.54 / 100 var F = 0.785 * Math.pow(Dm,2) var S1=0.55*Pw; var S2=Math.pow(S1,2) var S3=(2 * 1.24 * F * S2) var S = Math.pow(S3,0.333)/9.91 var nop = U*ke*0.66 //var eta_prop = (13.984 * Math.pow(J,2) + 43.59 * J + 48.1189)/100 if (RPMa < nop) {alert("Motor is overloaded!\nUse Motor with lower Kv, or prop with less diameter or less pitch.")} form.nw.value=Math.ceil(RPMa*ueb) form.nm.value=Math.ceil(nm) form.etam.value=Math.round(etam*100)/100 form.etamg.value=Math.round(etamg*100)/100 form.Pv.value=Math.ceil(Pv) form.Im.value=Math.round(Im*100)/100 form.Pw.value=Math.ceil(Pw) form.Uk.value=Math.round(Uk*100)/100 form.Vp.value=Math.round(Vp*100)/100 form.Vf.value=Math.round(Vf*100)/100 form.S.value=Math.round(S*10)/10 } // End > 


Rhode Island USA
Joined Aug 2010
5,350 Posts

This thread has my head spinning, is there a basic formula to determine Prop size, Motor size, ESC rating and battery size for a specific plane.
Thanks VP 




USA, ME, Ellsworth
Joined May 2008
18,023 Posts

Quote:
http://flbeagle.rchomepage.com/softw..._imperial.html There are different ways to approach or do it. If you have a plane and know the prop that is about right for it, you can work it from there but you also have to make some decisions too. How long do you want to fly? Do you want to fly a fast and maneuver aggressively? Do you want to just cruise the pattern and fly touch and goes? Jack 




Quote:
Best, Josh http://www.castlecreations.com/suppo...alculator.html 




Hi Victory Pete
There is no basic formula to determine Prop size, Motor size, ESC rating and battery size for a specific plane. In the attachment I have an easy procedure to calculate the inputs needed for some eflight calculators, but it is only a rough estimate. The aim is to calculate the basic requirements for a good motor and prop selection. Best regards Micha 


Rhode Island USA
Joined Aug 2010
5,350 Posts

Thanks for the help guys!
VP 




Manila, Philippines
Joined Jul 2004
1,239 Posts

Guys, I have notice that most of the Flight Calculator is designed for Airplane only.
I have use the Flight Calculator created by Castle Creation on my Helicopter, its very accurate in predicting the Flight time. I've been experimenting with different Battery Configuration from 6S,7S,8S,10S....by entering the Weight of Helicopter, Motor, Speed Controller, Rotor Diameter, Gear Ratio, it can compute the Flight Time, efficency of motor and even give you graphical display. http://www.castlecreations.com/suppo...alculator.html 



Quote:
The accuracy is limited by the accuracy of manufacturers regarding the motors Rm (milliohm) Kv (rpm/V) Io or iron losses (generally Io for only one voltage, in fact Io is depending of rpm) In Scorpion Calc, Dualsky Calc, Motrolfly Calc I have tested 95% or 100% of motors on my bench. Motor data are coming from testings. Same for Dr Kiwi tables and results. But anyway CC emotorcalc is very well done and useful for a "ball park prediction" Louis 




@ Fourdan
Today I have compared my own drive calculator with the Scorpion_Calc V3.43. There is only a slight differenence between both calculators. Best regards Micha 



Statistical Spread
@Furdan
your bench testing must not necessarily generate better results than the munufacturer data as the manufacturing process it self leads to a statistical spread  to take this spread into account and smoothen the manufacturing spread you should have tested at least 5 to 10 motors of the same type  did you? the mean figuers of the manufacturer resulting from tests over more than one motor of the same type  this is how the quality testing of the mufacturing process is done.... The Iron Loss is only indirect related to the RPM  It is related to the magnetic Cycles and these depends not only on the RPM but also on the numer of magnetic pols. Further more the CC eCalc does extrapolate the Iron Loss (Io) from the mesured mag. cycles (@ Io Voltage) to the effectiv mag. Cycles (at operational Voltage) by using an adequat mathematic model. nevertheless your Calc is also well done..... cheers eJet 
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