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Old Mar 27, 2011, 10:35 AM
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Ken Myers's Avatar
Commerce Township, MI
Joined Aug 2001
4,522 Posts
Ascent 450 Brushless PNP by E-flite
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 E-flite
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.
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Old Mar 31, 2011, 11:20 PM
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Joined Mar 2009
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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.
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Old Apr 01, 2011, 03:54 PM
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snoopy_schulz's Avatar
Germany, lake of constance
Joined Oct 2010
407 Posts
Hi apucjames

You need a 18x8 APC E prop.

Best regards
Micha
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Old Jun 27, 2011, 04:20 AM
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Fourdan's Avatar
Antony (France)
Joined Sep 2003
3,019 Posts
Quote:
Originally Posted by snoopy_schulz View Post
Hi apucjames

You need a 18x8 APC E prop.

Best regards
Micha
Hi Micha
When I try to visit the website snoopy-schulz.square7.ch
my security software is warning "this website is dangerous"
What is your opinion about that ?
Louis
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Old Jul 08, 2011, 02:31 AM
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snoopy_schulz's Avatar
Germany, lake of constance
Joined Oct 2010
407 Posts
Quote:
Originally Posted by Fourdan View Post
Hi Micha
When I try to visit the website snoopy-schulz.square7.ch
my security software is warning "this website is dangerous"
What is your opinion about that ?
Louis
Hi Louis

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
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Old Jul 08, 2011, 08:15 AM
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snoopy_schulz's Avatar
Germany, lake of constance
Joined Oct 2010
407 Posts
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 ausgewählt ?
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)*(Ishort-iL)+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=(Ishort-Ke*RPMa/Rg)///Motor current
var Uk=U-(Raccu+0.01)*Im // terminal voltage ot the motor
//var etam=(1-Im/(Uk/Rm))*(1-iL/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 -->
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Old Jul 08, 2011, 05:03 PM
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Rhode Island USA
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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
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Old Jul 08, 2011, 05:30 PM
Jack
USA, ME, Ellsworth
Joined May 2008
17,221 Posts
Quote:
Originally Posted by Victory Pete View Post
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
Do you have the airplane? Try entering the info on it here:

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
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Old Jul 09, 2011, 03:11 AM
Flying Full Size & Fun Size :)
jgalexander's Avatar
United States, CA, Calabasas
Joined Apr 2010
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Quote:
Originally Posted by Victory Pete View Post
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
Pete, the only way I've been able to determine all of the above is through trial and error. I use this calculator from Castle Creations - it makes sense to me, and has data preloaded for lots of common motors/ESCs (or you can choose 'custom' and input your own data).
Best,
Josh

http://www.castlecreations.com/suppo...alculator.html
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Old Jul 09, 2011, 01:54 PM
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snoopy_schulz's Avatar
Germany, lake of constance
Joined Oct 2010
407 Posts
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 e-flight 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
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Old Jul 09, 2011, 01:57 PM
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Joined Aug 2010
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Thanks for the help guys!
VP
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Old Jul 12, 2011, 09:53 PM
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Manila, Philippines
Joined Jul 2004
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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
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Old Jul 13, 2011, 05:57 AM
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Fourdan's Avatar
Antony (France)
Joined Sep 2003
3,019 Posts
Quote:
Originally Posted by lazy-b View Post
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
Hi
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
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Old Jul 13, 2011, 10:54 AM
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snoopy_schulz's Avatar
Germany, lake of constance
Joined Oct 2010
407 Posts
@ 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
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Old Jul 21, 2011, 01:15 PM
electric power,what else!
eJets's Avatar
Joined Dec 2005
269 Posts
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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