I'm about to build my first RC plane and I'd like to know how big my plane can be for my motor

[Creylo]

Hello! I have a 1000kv motor, 25*35mm big and im not sure about the weight. With the motor i have a 1060 propeller and a 30amp ESC with 3S 2200 mah lipo battery. I would like to know what airplane sizes are available for my setup. I have seen videos with people where people use similar setups like mine for 1400mm wingspan planes to 950mm wingspan planes but i wanted to be 100% sure if my equipment will be able to fly planes with the above mentioned wingspan.

 

[Merv]

...I would like to know what airplane sizes are available for my setup...

It depends on how you want to fly. Here are some guidelines that may help. It’s the total flying weight of the plane that you need, including motor and battery. Use the all up weight of the plane in the air.

• 50 to 70 watts per pound is the minimum level of power, good for park flyers and lightly loaded slow flyers.
•70 to 90 watts per pound is perfect for trainers and slow-flying aircraft.
•90 to 110 watts per pound is good for fast-flying scale models and some sport aerobatic aircraft.
•110 to 130 watts per pound is what you want for advanced aerobatics and high-speed aircraft.
•130 to 150 watts per pound is needed for lightly loaded 3D models and ducted fans.
•150 to 210+ watts per pound gives unlimited performance for any 3D model.

 

[Creylo]

It depends on how you want to fly. Here are some guidelines that may help. It’s the total flying weight of the plane that you need, including motor and battery. Use the all up weight of the plane in the air.

• 50 to 70 watts per pound is the minimum level of power, good for park flyers and lightly loaded slow flyers.
•70 to 90 watts per pound is perfect for trainers and slow-flying aircraft.
•90 to 110 watts per pound is good for fast-flying scale models and some sport aerobatic aircraft.
•110 to 130 watts per pound is what you want for advanced aerobatics and high-speed aircraft.
•130 to 150 watts per pound is needed for lightly loaded 3D models and ducted fans.
•150 to 210+ watts per pound gives unlimited performance for any 3D model.

Thanks! But how do I know how many watts my motor has?

 

[Piotrsko]

Sounds equivalent to what FT considers a "C" motor so couple of pounds airborne easily. You want enough wingspan to will slow you down since this combo will fly on a 750 mm craft but be really twitchy fast and agile. Meter and a half perhaps, and boxy shape for ease of build.

Watts are battery voltage times current. So in your case 11.5 volts times 30 amps or 345 watts or about 1/2 hp

 

[Merv]

Thanks! But how do I know how many watts my motor has?

The motor vendor should give you this information, if they don't look at a similar motor. All motors of a given size and Kv are going to have similar watts.

I agree with Piotrsko, Amps x Volts = Watts.

Another useful ratio is the thrust the prop produces per the weight of the plane.
A thrust to weight ratio of 1:1 will be a good flyer, 1.5:1 will be aerobatic, 2+:1 will be a rocket.

This motor has the following specs, it should be similar to the motor you are looking at.
Tested wiht 11.1V voltage and 1045 prop:
Load current: 10.6A
Pull: 710g
Power: 118W
Efficiency: 6.0 (g/W)

Bottom line, a plane weight of 600-750g will work great.

 

[Creylo]

The motor vendor should give you this information, if they don't look at a similar motor. All motors of a given size and Kv are going to have similar watts.

I agree with Piotrsko, Amps x Volts = Watts.

Another useful ratio is the thrust the prop produces per the weight of the plane.
A thrust to weight ratio of 1:1 will be a good flyer, 1.5:1 will be aerobatic, 2+:1 will be a rocket.

This motor has the following specs, it should be similar to the motor you are looking at.
Tested wiht 11.1V voltage and 1045 prop:
Load current: 10.6A
Pull: 710g
Power: 118W
Efficiency: 6.0 (g/W)

Bottom line, a plane weight of 600-750g will work great.

Thanks! All my specs were originally used in a 1400mm wingspan plane that weights around 600-750g which matches pretty well with your and piotrskos descriptions. Many people have told me to use my specs for the FT simple scout, but am i better of building the plane where i originally got my specs? It seems less complicated and this is my first plane and i would love a slow flyer that i train with.
Here is the link to the video:

 

[Creylo]

It depends on how you want to fly. Here are some guidelines that may help. It’s the total flying weight of the plane that you need, including motor and battery. Use the all up weight of the plane in the air.

• 50 to 70 watts per pound is the minimum level of power, good for park flyers and lightly loaded slow flyers.
•70 to 90 watts per pound is perfect for trainers and slow-flying aircraft.
•90 to 110 watts per pound is good for fast-flying scale models and some sport aerobatic aircraft.
•110 to 130 watts per pound is what you want for advanced aerobatics and high-speed aircraft.
•130 to 150 watts per pound is needed for lightly loaded 3D models and ducted fans.
•150 to 210+ watts per pound gives unlimited performance for any 3D model.

I calculated the watts and i have a motor that has 4-10 amps current. I took the 11.5 x 10 and got 115 watts. My plane will weigh maybe around 1.5 pounds meaning my plane will be perfect for the 70-90 per pound plane while also cutting me some slack incase my plane is overweight!

 

[Creylo]

Sounds equivalent to what FT considers a "C" motor so couple of pounds airborne easily. You want enough wingspan to will slow you down since this combo will fly on a 750 mm craft but be really twitchy fast and agile. Meter and a half perhaps, and boxy shape for ease of build.

Watts are battery voltage times current. So in your case 11.5 volts times 30 amps or 345 watts or about 1/2 hp

Thanks so much! My specs were originally found in the equipment description of a 1400mm plane with a boxy shape, the plane was meant for a trainer/ newbie plane which lines up absolutely perfectly with what Merv said! Seems like everything is lining up and i should follow the YouTube tutorial and build the plane my equipment was originally found in. I want to minimize my costs in this hobby so it would be great if i could reuse all of my equipment in different planes. Just a quick question to check if a have understood all this information correctly, if i were to take the exact same motors battery's etc and reduce the wingspan and weight of the plane i would be able to make a more aerobatic and faster aircraft. Huge thanks to both of you guys, this information has guided me immensly and given me a lot more confidence!

 

[The Fopster]

You can definitely use the electronics in other planes. Maybe Simple Scout would be a good second plane, then maybe simple spitfire for a first warbird. You can make that faster by using a different propeller - smaller diameter and higher pitch.

 

[Creylo]

You can definitely use the electronics in other planes. Maybe Simple Scout would be a good second plane, then maybe simple spitfire for a first warbird. You can make that faster by using a different propeller - smaller diameter and higher pitch.

That sounds awesome, but don't i need a higher KV motor for a smaller prop? Or is the higher KV just faster and more ideal while the lower KV with smaller prop will still work but be a little ineffective and not as fast as the lower KV one?

 

[The Fopster]

That sounds awesome, but don't i need a higher KV motor for a smaller prop? Or is the higher KV just faster and more ideal while the lower KV with smaller prop will still work but be a little ineffective and not as fast as the lower KV one?

That sounds awesome, but don't i need a higher KV motor for a smaller prop? Or is the higher KV just faster and more ideal while the lower KV with smaller prop will still work but be a little ineffective and not as fast as the lower KV one?

You don’t need a higher kv. The increased pitch has the same effect - you move the air faster, either by increasing the kv and spinning the prop at a higher rpm, or by increasing the pitch and moving the air faster but at the same lower rpm. Same effect, and no need for another motor.

 

[Creylo]

You don’t need a higher kv. The increased pitch has the same effect - you move the air faster, either by increasing the kv and spinning the prop at a higher rpm, or by increasing the pitch and moving the air faster but at the same lower rpm. Same effect, and no need for another motor.

Woah, that is a total game changer! I had no idea that i could build whatever plane i wanted with my motor! Thanks so much! If i understand correctly pitch is the amount you travel each time the prop spins and for a higher KV you want lower pitch and for lower KV you want higher pitch? Thanks again!

 

[The Fopster]

Woah, that is a total game changer! I had no idea that i could build whatever plane i wanted with my motor! Thanks so much! If i understand correctly pitch is the amount you travel each time the prop spins and for a higher KV you want lower pitch and for lower KV you want higher pitch? Thanks again!

You got it. Onwards and upwards!