Flounder

I remember seeing a post that had a calculation on wing area, weight and prop size - or something like that. How do you figure out the prop size and motor for any plane?

Thanks for your responses....

Jim Finn

My Feedback: (2)

Do a search for "Motocalc" or Electracalc" either of these programs will answer all of your questions regarding electric plane and powers systems design. I use electracalc but I know you can download Motocalc free for 30 days to try. One of these programs is a "must" if you plan to fly electrics.

Matt Kirsch

My Feedback: (21)

The problems with these "calc" programs are that they generally don't incorporate the latest motors and battery technology, they only get you in the ballpark, and they are completely useless for a newbie who has no clue what all the numbers mean.

Powering airplanes with electricity is more of an art form than a science.

IMHO, the best way to figure out a power system when you're just getting started in electrics is to not figure it out at all. Find someone who's already SUCCESSFULLY converted an airplane with similar characteristics, and copy their power system. By studying that power system, you'll learn the relationships between cell count, motor characteristics, gear ratios, and propeller sizes. In no time flat, you'll be able to choose a cell count by just looking at an airplane, you'll have a favorite brushless motor manufacturer (which makes motor selection easier), and you'll have a rough idea of the gear ratio and prop size you need to fly a particular plane a particular way.

Jim Finn

My Feedback: (2)

I dissagree! Selecting a power system and an airframe for electric is a science not an art. I started copying a plane and I ended knowing only about my plane and power system. Yes it flew but to try another plane I needed electracalc..........Different strokes..different opinions.

Matt Kirsch

My Feedback: (21)

If you focus on ONE plane, that's what's going to happen. You will only know about that one plane. However, if you expand your horizons and see what people are doing with many different planes, you start to see a trend. You start to realize that yes, a .40-size plane needs 12 to 16 cells, depending on if it's a trainer-type or an aerobatic ship.

I use the *Calc programs myself, but only to confirm my choices. They're usually optomistic about the performance of certain combinations.

slehmann

Here's a link to an amazing page of articles about EP flight. It's become my bible. Check out the ones about picking good power package and Sport electric scale.........

http://members.aol.com/KMyersEFO/page3.htm

Slehmann