KerryQuinn
Well-Known Member
- Joined
- May 5, 2009
- Messages
- 136
- Reaction score
- 0
I have been trying to come up with a methodical way to select engine & parachute sizes and launch rod angles and rod directions to keep rockets away from the flight line AND still on the flying field. Ted Cochran gave an excellent talk at Narcon2010 on flying safely - and that got me thinking further.
I have been running a bunch of simulations using OpenRocket to try to see how these variables interact at 10mph and 20mph winds. Here is a summary of some of my findings so far. I'm looking for feedback from the group to see if these findings make sense - and for suggestions on how to expand upon this study....
My study so far is for one of the home flying fields for the foxvalley rocketeers. All of the work below is for an AlphaIII flying on a C6-5 at this field on days with 10mph and 20mph winds with the winds blowing to the west (view in the figures is looking towards the north)
Our flightline is usually set up parallel to the southern edge of the parking lot.
In these simulations I flew with launch rod direction (LRD) pointed at 0/45/90/135/180 degrees where 0 degrees is into the wind. I also looked at launch rod angles (LRA) of 10 and 20 degrees off vertical. I studied normal deploys of an 8" and 12" chute as well as non-deploy (lawndart) flights.
My findings (see attached plots) suggest that angling the LRA 10 or 20 degrees AWAY from the flight line is a good idea (no suprise), that using a smaller chute keeps the rocket on the field (no suprise) and that flying in lower winds keeps the rockets on the field (no suprise).
The results also suggest that flying with a LRD of between 90 degrees (crosswind) and 45 degrees into the wind is optimal for our flying field. (One thing not obvious from these google_earth plots is that the area downwind of the soccer fields is a swamp.)
A problem with this type of analysis, however, is that it is all for a single rocket & engine & wind direction. I'd like to be able to generalize the analysis without having to re-run all of the cases for every rocket, engine, wind combination. Since peak altitude, stability and inertia are all significant, I don't see a way around this.... any thoughts?
-Kerry
I have been running a bunch of simulations using OpenRocket to try to see how these variables interact at 10mph and 20mph winds. Here is a summary of some of my findings so far. I'm looking for feedback from the group to see if these findings make sense - and for suggestions on how to expand upon this study....
My study so far is for one of the home flying fields for the foxvalley rocketeers. All of the work below is for an AlphaIII flying on a C6-5 at this field on days with 10mph and 20mph winds with the winds blowing to the west (view in the figures is looking towards the north)
Our flightline is usually set up parallel to the southern edge of the parking lot.
In these simulations I flew with launch rod direction (LRD) pointed at 0/45/90/135/180 degrees where 0 degrees is into the wind. I also looked at launch rod angles (LRA) of 10 and 20 degrees off vertical. I studied normal deploys of an 8" and 12" chute as well as non-deploy (lawndart) flights.
My findings (see attached plots) suggest that angling the LRA 10 or 20 degrees AWAY from the flight line is a good idea (no suprise), that using a smaller chute keeps the rocket on the field (no suprise) and that flying in lower winds keeps the rockets on the field (no suprise).
The results also suggest that flying with a LRD of between 90 degrees (crosswind) and 45 degrees into the wind is optimal for our flying field. (One thing not obvious from these google_earth plots is that the area downwind of the soccer fields is a swamp.)
A problem with this type of analysis, however, is that it is all for a single rocket & engine & wind direction. I'd like to be able to generalize the analysis without having to re-run all of the cases for every rocket, engine, wind combination. Since peak altitude, stability and inertia are all significant, I don't see a way around this.... any thoughts?
-Kerry