What motor?
- Thread starter Magne
- Start date
Paracodespoder
Elite member
That question is more easily answered by deciding what kind and size of airplane you want to do. Are you looking at FT airplanes or designing your own? What size and material? Motor choice is based entirely on what size plane, style of flying you are anticipating, and a little bit on your skill level.
A good rule of thumb is to look at an existing model that is similar in size, weight, and performance to what you want to build. Then borrow the recommended power system. (motor, ESC, battery, prop) There are more math based approaches to sizing a power system but this is a good simple method that will work well for most cases.
For example all the Mighty Mini airplanes use the same power system.
For example all the Mighty Mini airplanes use the same power system.
FlyerInStyle
Elite member
Another good rule of thumb is to have more than 1:1, more like 1.5:1 thrust to weight ratio. there are plenty of thrust calculators, and many motors will even say what sized plane they are for. Also, remember to get an appropriately sized esc for your motor. Most designs will also recommend a motor and propeller size. For the arrow, something like an 1806 maybe if you want more power a 2204 at 2200kv should be good.
Good luck in your builds
Good luck in your builds
Foamforce
Well-known member
The rule of thumb I’ve seen is to get a motor that has a thrust to weight ratio of at least 1:1 for a trainer, 1.5:1 for acrobatic, or 2:1 for 3d flying.
For the mighty mini arrow, the all up weight is listed at 170g without battery. The suggested 3 cell 800mah is another 80g, so 250g total. If you wanted to do acrobatics with that, you would then want around 250x1.5=375g of thrust. The 2204 2300kv motor they recommend puts out something like 440g thrust so you would have 1.76:1 thrust ratio, so pretty peppy.
You can find the thrust rating of motors on either the manufacturers website or the sellers website sometimes. It’s kind of a crapshoot though.
For the mighty mini arrow, the all up weight is listed at 170g without battery. The suggested 3 cell 800mah is another 80g, so 250g total. If you wanted to do acrobatics with that, you would then want around 250x1.5=375g of thrust. The 2204 2300kv motor they recommend puts out something like 440g thrust so you would have 1.76:1 thrust ratio, so pretty peppy.
You can find the thrust rating of motors on either the manufacturers website or the sellers website sometimes. It’s kind of a crapshoot though.
FlyerInStyle
Elite member
I have 1:1 on my trainer and it does not fly too well. I try to make everything 1.5:1 just to have that extra little bit of power if I need it
Foamforce
Well-known member
Yeah, that was my experience too, and is probably why FT designs tend to be slightly over powered. When I originally built the Storch, I had a B pack equivalent motor in it which wasn’t quite 1:1. I could fly it, but it was somewhat difficult to recover from mistakes. On the other end of the spectrum, I built a Delta and overpowered it, and that was difficult too because I got into trouble so fast!
Shurik-1960
Well-known member
Tables of the main model aircraft engines with characteristics
http://rc-aviation.ru/?option=com_rcbase&view=motorlist
http://rc-aviation.ru/?option=com_rcbase&view=motorlist
A lot of it depends on size of the plane, weight of the plane, what power source you're going to use (2S, 3S, 4S, etc.) and prop size, all of which affect the other factors of size of plane, weight of plane, what power source, etc.
For example:
Let's say I build a generic Versa Wing. I have used an 1100kv A2212 motor for them before. It flies well with a 3S battery and an 8x8 two blade pusher prop; however, it's not necessarily the only solution. There are guys in my club who run the same Versa Wing with a 3S battery, but they'll fly with a 2200kv motor (I want to say a 2205 or 2210?) with a 6x3 two blade prop, and get a little bit better performance, albeit with a little less flight time than I get on my setup. Different setups, different motors, similar performance.
My best recommendation is to try using something like eCalc to help you narrow down performance stats. Worth the money, IMHO!
Shurik-1960
Well-known member
sprzout , I read about your ever - expanding hangar .I am also a maniac - I have more than 36 homemade models. A special room in a house in the village is completely packed with models and I have attached a veranda to the house 4mx6m and in the summer I collect models in it.
https://ibb.co/zfxFHRQ
https://ibb.co/P9pZ2y7
My rule of making a model. 1. I make a fully glider with electronics without an engine and regulator. 2. Weigh the model with the battery. 3. I consider the load that turned out to be on the wing. 4. Pick up the engine + regulator with the desired thrust: fly pancake or hooligan 5. I install the reg + motor frame with the engine and select the position of the box for the battery with the desired alignment of the model.6. I throw the finally assembled model on the grass or snow, trimming and making sure that the CG is good. 7. The first flight.
https://ibb.co/zfxFHRQ
https://ibb.co/P9pZ2y7
My rule of making a model. 1. I make a fully glider with electronics without an engine and regulator. 2. Weigh the model with the battery. 3. I consider the load that turned out to be on the wing. 4. Pick up the engine + regulator with the desired thrust: fly pancake or hooligan 5. I install the reg + motor frame with the engine and select the position of the box for the battery with the desired alignment of the model.6. I throw the finally assembled model on the grass or snow, trimming and making sure that the CG is good. 7. The first flight.
