Help! Help with simple cub electronics?

[FFA_is_Plane_ATF]

Hey guys, I'm brand spankin' new here, and new to this hobby (just built my first plane) and have little knowledge of the electronics side except the basics...

I've got my simple cub completed, electronics installed (30a simonk firmware ESC, 11.1V 3S 2200MAH 50C ovonic brand battery, a flysky r6b reciever, 2 9g sg90 servos, and an a2208-14T 1400kv motor, and a total plane weight of around 780g)...

I've been doing tons of research trying to figure out how to determine the prop size for a setup, but between my adhd and lack of any straightforward formulas/information I have zero clue what prop size I should be using. I was having trouble finding an actual data sheet for my motor, and the one source said it had a reccomended prop size of 8×4, I went ahead and ordered a few but they wont be here for some time, in the meantime, I 3d printed an 8×4 prop and it just wasn't enough power. It'd taxi but not fly, would stall after 20 feet probably... my CG is within the 1.75 inches the guide says...

If someone could help me learn how to determine/calculate the motor size and prop I should use for this plane (and future planes), I would be forever grateful. I'm not looking to be spoonfed the answer, I really just need to know how to do this.

 

[Mr NCT]

Without a power & prop chart for a motor or the manufacturer suggesting a prop about all you can do is build your own test stand to find amp draw and thrust.
Just starting out it might be best to go with a power set up that the designer recommends. The simple cub calls out a "B" power pack that has a 2212 x 1080kv motor with a 9x4.5 prop, so you could buy theirs or get something comparable so that you start with a combination that is known to work.

 

[Foamforce]

A 2208 is too small for the Cub. You can orobably get it off the ground with perfect conditions and good flying, but it will be tough. Instead, get a 2212 900-1100kv motor, which cost about $7, and use a 9x4.5 or 10x4.5 prop with it. Another thing that will make it easier to fly is to start with a smaller battery, such as a 1300mah 3s. Lastly, taking off on landing gear adds a lot of difficulty. The wheels usually aren’t lined up very well, so you have to use a lot of rudder to keep it straight on the ground, and that’s more difficult that you might expect (for a beginner). Removing the landing gear in the Cub makes it lighter and less drag, improving handling.

PS, to your original question, yes, the 8x4 is the right motor for the 2208/1400kv. On this chart you can see that it‘s rated at a maximum of 12 amps. The 8x4 prop tested with it gives the most thrust of any prop tested that doesn’t exceed 12 amps. When you exceed the max amps, the motor can get too hot and burn out. You’ll know when that has happened when it no longer spins freely by hand, and you can see crusty black/brown stuff on the visible windings, which is the coating on the windings that has melted off.

Suppo - A2208-14 - FlyBrushless.com

 

[Bricks]

What Foamforce said max weight of the 2208 1400kv is recommended 500 grams so you are way under powered.

 

[FFA_is_Plane_ATF]

A 2208 is too small for the Cub. You can orobably get it off the ground with perfect conditions and good flying, but it will be tough. Instead, get a 2212 900-1100kv motor, which cost about $7, and use a 9x4.5 or 10x4.5 prop with it. Another thing that will make it easier to fly is to start with a smaller battery, such as a 1300mah 3s. Lastly, taking off on landing gear adds a lot of difficulty. The wheels usually aren’t lined up very well, so you have to use a lot of rudder to keep it straight on the ground, and that’s more difficult that you might expect (for a beginner). Removing the landing gear in the Cub makes it lighter and less drag, improving handling.

PS, to your original question, yes, the 8x4 is the right motor for the 2208/1400kv. On this chart you can see that it‘s rated at a maximum of 12 amps. The 8x4 prop tested with it gives the most thrust of any prop tested that doesn’t exceed 12 amps. When you exceed the max amps, the motor can get too hot and burn out. You’ll know when that has happened when it no longer spins freely by hand, and you can see crusty black/brown stuff on the visible windings, which is the coating on the windings that has melted off.

Suppo - A2208-14 - FlyBrushless.com

Thanks so much! I ordered a bunch of motors the other day, got a few different kv ratings within the range you specified, I'll update once they come on how it goes!