CanSat Rover 2526: Difference between revisions
(→Idea) |
(→Thrust) |
||
| (7 intermediate revisions by the same user not shown) | |||
| Line 57: | Line 57: | ||
Powering the sensors and external components separately is highly recommended. | Powering the sensors and external components separately is highly recommended. | ||
Motor options | |||
* BetaFPV 19000KV Motor (7x16mm), 2.95g, 3.7V | |||
=== Thrust === | |||
The thrust coefficient, <math>C_T</math> measures how much thrust a propeller makes compared to the air pressure it faces. | |||
<math> | |||
Thrust = C_T \times \rho \times A \times (\omega \times r)^2 | |||
</math> | |||
{| class="wikitable" | |||
|+ Example | |||
|- | |||
! Header text !! Header text !! Header text | |||
|- | |||
| <math>C_T</math> || 0.12 || | |||
|- | |||
| <math>\rho</math> || 1.225 || kg/m³ | |||
|- | |||
| Propeller area <math>A</math> || 0.0314 || m² | |||
|- | |||
| Angular Velocity (ω) || 314 || rad/s | |||
|- | |||
| Propeller Radius (r) || 0.1 || m | |||
|} | |||
Pushing force. The mass of the cansat should be 300–350 g. | |||
# RPM. More RPM => more thrust. | |||
## KV: How fast the motor spins per volt. | |||
## Voltage | |||
#Propeller | |||
# Diameter <math>d</math> | |||
# Pitch | |||
#Motor efficiency | |||
Thrust (in grams): | |||
<math> | |||
= 4.92 x (Propeller Diameter in inches)^2 x (Propeller Pitch in inches) x (Motor KV)^2 x (Battery Voltage)^2 / 1,000 | |||
</math> | |||
=== Waterproofing the axle (driveshaft) === | === Waterproofing the axle (driveshaft) === | ||
Latest revision as of 19:43, 9 December 2025
Introduction
Mechanics
Folding
1. Rover
Tires and motors
https://www.vcalc.com/wiki/vcalc/rpms-to-linear-velocity
| RPM | Speed (cm/s) |
|---|---|
| 15 | 6 |
| 30 | 3.1 |
| Example | Example |
| 68 | 14.2 |
| 381 | 79.796 |
| Example | Example |
Designs
1
2
2. Boat / Snowmobile
Idea
Aerosled
With tutorials etc https://www.thingiverse.com/thing:4496127
- XXD HW30A 30A Brushless Motor ESC For Airplane Quadcopter.
- Weight: 25g
- Dimensions: 45 x 24 x 11mm
- Price: 6€
- Racerstar BR2212 2450KV 2-3S Brushless Motor For RC Models
- Weight: 52g
Power Arduino/ ESP32 from a powerbank. ESP32
- 2.2V to 3.6V input voltage. 3.3V is optimal. Cells around 3.7V (Li-ion) provide ideal voltage. V_in(max) = 12...16V?? The voltage regulator is AMS1117: may run hot if too much voltage.
- 10 mA - 500 mA
- ESP32 incorporates a regulator that steps down higher voltage supplies to a steady 3.3V output. The common AMS1117 regulator can deliver up to 800 mA, sufficient for most applications.
Powering the sensors and external components separately is highly recommended.
Motor options
- BetaFPV 19000KV Motor (7x16mm), 2.95g, 3.7V
Thrust
The thrust coefficient, measures how much thrust a propeller makes compared to the air pressure it faces.
| Header text | Header text | Header text |
|---|---|---|
| 0.12 | ||
| 1.225 | kg/m³ | |
| Propeller area | 0.0314 | m² |
| Angular Velocity (ω) | 314 | rad/s |
| Propeller Radius (r) | 0.1 | m |
Pushing force. The mass of the cansat should be 300–350 g.
- RPM. More RPM => more thrust.
- KV: How fast the motor spins per volt.
- Voltage
- Propeller
- Diameter
- Pitch
- Motor efficiency
Thrust (in grams):
Waterproofing the axle (driveshaft)
Underwater sealing. A rotary shaft seal. Sealed bearing. Stuffing tube. Water channeling. Stuffing box.
The axle passes through an arrangement called a "gland".
- a wide tube filled with discs of material and grease
- a standard lip seal
- magnetic coupling
Marine grease
- https://robotics.stackexchange.com/questions/150/preventing-leaks-in-motor-shafts-for-underwater-bots
- http://www.building-model-boats.com/model-boat-propeller-shaft.html
- https://seaperch.org/resources/library/#build
- https://www.mechanicalseals.net/
- https://ntrs.nasa.gov/api/citations/19670006352/downloads/19670006352.pdf
for submarines and 3d prints, check Making 3D prints actually waterproof https://www.youtube.com/watch?v=Q8x-mjjT8j4
Turning the motor
Use a servo to turn the motor. Eg
