Iris Ultra Parachutes Cd Performance Log
The table below shows our measurements done over a period of 5 years to accurately determine the coefficient of drag (Cd) of the Iris Ultra Parachutes.
All tests were performed after having measured the weight of the rocket upon landing. In addition, we had precise information on the parachutes themselves and used altimeters to log the data.
Factors which affect the coefficient of drag include:
- altitude
- barometric pressure
- air temperature
- humidity
Given that the altitude stays constant, the factors above can cause the Cd to vary by up to 20%. Fruity Chutes rating of 2.2 Cd is considered to be very close to the worst case that we had measured over many flights.
| Drone, Rocket, Company | Tester | Parachute | Date | Diameter (inches) | Recovery Weight (lb) | Descent Speed(ft/sec) | Calculated Cd Frontal Area |
|---|---|---|---|---|---|---|---|
Mag Max |
GE |
IFC-72 |
4/1/2011 |
72 |
15.53 |
15.05 |
2.103 |
Mag Max |
GE |
IFC-60 |
5/20/2011 |
60 |
16.1 |
17.9 |
2.219 |
Comp 4 |
GE |
IFC-72 |
5/21/2011 |
72 |
23.3 |
16.95 |
2.487 |
Comp 4 |
GE |
IFC-72 |
4/7/2012 |
72 |
22 |
18 |
2.083 |
Comp 4 |
GE |
IFC-72 |
5/19/2012 |
72 |
23.6 |
16.85 |
2.549 |
Comp 4 |
GE |
IFC-72 |
6/16/2012 |
72 |
23 |
16.75 |
2.514 |
Not sure |
DR |
IFC-60 |
7/20/2012 |
60 |
16.8 |
18.5 |
2.168 |
Max Maxx Thunderdome |
GE |
IFC-72-ZP |
1/2/2016 |
72 |
19.025 |
13.97 |
2.990 |
MN Drone |
Ido |
IFC-66-SUL |
1/22/2016 |
66 |
13.78 |
14.57 |
2.369 |
MN Drone |
Ido |
IFC-66-SUL |
1/22/2016 |
66 |
13.78 |
12.66 |
3.138 |
MN Drone |
Ido |
IFC-66-SUL |
1/22/2016 |
66 |
13.78 |
13.06 |
2.949 |
MN Drone |
Ido |
IFC-72-SUL |
1/22/2016 |
72 |
13.78 |
12.7 |
2.620 |
MN Drone |
Ido |
IFC-72-SUL |
1/22/2016 |
72 |
13.78 |
11.45 |
3.224 |
MN Drone |
Ido |
IFC-72-SUL |
1/22/2016 |
72 |
13.78 |
12.57 |
2.675 |
MN Drone |
Ido |
IFC-72-SUL |
1/22/2016 |
72 |
13.78 |
12.04 |
2.916 |
Mag Maxx Thunderdome |
GE |
IFC-72-ZP |
2/6/2016 |
72 |
19.025 |
15.6 |
2.398 |