03-Feb-2019, 11:55 PM
Hello,
I am currently designing, of all things, a rocket for a competition called TARC (Team America Rocketry Challenge).
One of the score parameters is total flight time, so my idea was to use a single propeller in combination with a parachute. The propeller wouldn't necessarily need to be powerful enough to allow the rocket to hover, but it would be able to somewhat control the speed of descent in conjunction with a parachute after the rocket is falling back to the ground.
I thought it would be simple enough to find the parts I need especially because the drone community is fairly large but boy was I wrong.
I did a lot of research regarding motors and propellers and batteries and ESCs and flight controllers but there are just so many different things to look into and I was wondering if somebody with experience can help point me in the right direction and narrow down the things I need to some exact parts that might work.
There are a few notable challenges. The biggest one is weight. The rocket has a maximum weight limit of 650 g, so I really only have about 150 grams to work with for all electronics, the motor, the battery, and the propeller. That being said I want to maximize the power of the system so that it has a strong effect on the descent rate. Another challenge is size. All components need to fit inside a fairly small ~2-inch diameter rocket body tube. This means that I have to use a folding prop. The last big challenge is autonomy. Once the rocket is in the sky, I can't communicate with it anymore, so I need some sort of flight controller that I can program to adjust the propeller speed based on descent rate.
As far as motors go, I was looking into motors in the ~30 g range. The problems I'm running into for motors are finding an ideal kv, thrust, and efficiency. I can't really have a current guzzling motor because I need to keep the weight of the battery and electronics down. This also somewhat limits the possibility of having higher voltage lipos because 4s and 5s batteries tend to weight more. As far as kv goes, I've been looking into mid kv and low kv motors. I am somewhat limited to lower kvs, because folding propellers (usually used for model airplanes) have a lot fewer options than normal drone propellers. Additionally, folding prop spinners come in pretty limited sizes meaning I will likely have to find a motor with a 4 mm shaft size (that fits the folding prop spinner). For folding propellers, the 2 options on my radar are a 7 x 4 (18 x 10 cm) and a 6 x 3 (15 x 8 cm). These are pretty low pitches, which makes it hard to pair with a motor efficiently. The battery would really only need to power the motor for a maximum of 1 minute, so I'm looking for something with a high voltage and max current but super small capacity (for weight).
If anybody has ideas for motors, ESCs, batteries, flight controllers or other parts that fit parameters of the project, that would be greatly appreciated!
Thanks for reading this really long post,
Nolan
I am currently designing, of all things, a rocket for a competition called TARC (Team America Rocketry Challenge).
One of the score parameters is total flight time, so my idea was to use a single propeller in combination with a parachute. The propeller wouldn't necessarily need to be powerful enough to allow the rocket to hover, but it would be able to somewhat control the speed of descent in conjunction with a parachute after the rocket is falling back to the ground.
I thought it would be simple enough to find the parts I need especially because the drone community is fairly large but boy was I wrong.
I did a lot of research regarding motors and propellers and batteries and ESCs and flight controllers but there are just so many different things to look into and I was wondering if somebody with experience can help point me in the right direction and narrow down the things I need to some exact parts that might work.
There are a few notable challenges. The biggest one is weight. The rocket has a maximum weight limit of 650 g, so I really only have about 150 grams to work with for all electronics, the motor, the battery, and the propeller. That being said I want to maximize the power of the system so that it has a strong effect on the descent rate. Another challenge is size. All components need to fit inside a fairly small ~2-inch diameter rocket body tube. This means that I have to use a folding prop. The last big challenge is autonomy. Once the rocket is in the sky, I can't communicate with it anymore, so I need some sort of flight controller that I can program to adjust the propeller speed based on descent rate.
As far as motors go, I was looking into motors in the ~30 g range. The problems I'm running into for motors are finding an ideal kv, thrust, and efficiency. I can't really have a current guzzling motor because I need to keep the weight of the battery and electronics down. This also somewhat limits the possibility of having higher voltage lipos because 4s and 5s batteries tend to weight more. As far as kv goes, I've been looking into mid kv and low kv motors. I am somewhat limited to lower kvs, because folding propellers (usually used for model airplanes) have a lot fewer options than normal drone propellers. Additionally, folding prop spinners come in pretty limited sizes meaning I will likely have to find a motor with a 4 mm shaft size (that fits the folding prop spinner). For folding propellers, the 2 options on my radar are a 7 x 4 (18 x 10 cm) and a 6 x 3 (15 x 8 cm). These are pretty low pitches, which makes it hard to pair with a motor efficiently. The battery would really only need to power the motor for a maximum of 1 minute, so I'm looking for something with a high voltage and max current but super small capacity (for weight).
If anybody has ideas for motors, ESCs, batteries, flight controllers or other parts that fit parameters of the project, that would be greatly appreciated!
Thanks for reading this really long post,
Nolan
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