westridge

Hi I am also currently working on my Modeltech P51 40 size ARF with a weight: 6 lb., 8 oz.
an E conversion has been done and you can find it at [link=http://www.hobbypeople.net/review/123695man.htm]
I would like to go with a Hacker brushless motor as I already have one in my Logo 20 Heli and have had a good
experience with it so far. In the conversion they used a Aveox 27/39/2 motor and an MEC Superbox 60/20 gearbox. I am not very familiar with the numbers but would like to go with a Hacker and matching gear box with this kit.

- John

Matt Kirsch

My Feedback: (21)

Just to get you started, the numbers used to designate the motors aren't the same numbers you will be working with to figure out the power system.

The first number you'll be working with is Watts. A warbird will need at least 100 Watts per pound of airplane weight. 6 pounds 8 ounces? Let's say 7 pounds. That means you are shooting for 700 Watts of power with this plane.

The next numbers you'll be working with are cells and Amps. Here's where a newbie kinda needs to make a leap of faith. Once you've seen a few conversions, you'll notice a trend. Planes of certain sizes, like .40-size, generally have similar numbers of cells. .40-size planes generally have 14-18 cells. or a 4S to 5S LiPoly. Cell count translates directly into Volts, and Volts times Amps gives you Watts. 700 Watts divided by 14 cells is 50 Amps.

With a cell count and a current, you can go motor shopping. It doesn't matter what motor you get, as long as the motor can handle at least 14 cells at 50 Amps. Watts are the important factor. Because of this, you can choose your motor based on more tangible things like, quality, weight, price, reputation.

westridge

I was thinking about going with a Hacker B50 11S 5.2:1 as mentioned in another thread of mine awhile back. I would also like to find a well matched Lipo to go with it.

John

Silverhawk

My Feedback: (1)

Darn, I thought, maybe, this would be about the .60 size ARC. I have one of those sitting in the box waiting patiently for some attention. I even have the APC 15x12 4 blade prop for it already.

flo

Hi Ray.
why not go ahead? Mine is no arf by any means but the (very old Plan used for Outlines only) called for a 60 as well.
Ws is 1,80 m , I am using a 15,2 Inch Varioprop 4 bladed Prop via Lehner 1940/10 , Reisenauer "Superchief"6:1 gear on 9s3p 6000 mah Thunderpower 2.Gen. Lipos. The setup delivers 1500 Watts, 7kg trust to a 5,2kg Airframe. Propspeed is aprox 32 m/s so medium Speed only but definetly nice flying.
Hope this helps to get you started.
Happy new year.
Flo

Silverhawk

My Feedback: (1)

Flo,

I hope that I can get started fitting the pieces and covering the ARC. This will take longer and more attention to detail than any other plane I've ever done since it will be entered in scale comp.

I'm not looking for screaming vertical so I'll be more apt to go with a 5s3p and either use one of my Aveox motors or maybe spring for an outrunner. I'll be going for scale like performance with a little to get me out of trouble when needed.

Thanks for the info,

flo

Hi all. (sorry to for intruding this thred)

@Ray

5 S pacs might be fine for a scale like flight ... on a 2blade prop!
A 4 bladet prop will take much !! more Watts to turn the same Speed as a 2 bladet one.
I Did`t intend to prop for 7 kg trust but that was what i endet up when propping for a middle between desired speed and Amps consumed. I simply can`t make it faster without running too much Amps for my liking.
so If i was you i would think hard about if i would like to use 2 bl prop and go with 5S or go for something like 7-9S on a 4 bl prop.
Definetly 4 bl and 9S is overkill trustwise and as well Powerwise (aprox 290 W/kg) and Topspeed is surely not "Ahh " and "Ohh" but for me the coolness factor is worth it.
Not even the (few leftover) slimer Fans here are using 4 bl. props ! So for me it is worth the expense.
Btw. I can always trotlle back to about 15 % to just fly around ( 20 mins easy)

Greetings

flo