× Welcome to the CMASS forum!

A place to discuss anything related to CMASS (and other) launches.

L1 Certification Help

More
6 months 2 weeks ago #11951 by deangelo54
Replied by deangelo54 on topic L1 Certification Help
Both DeltaVee and Claude are experienced fliers. If we have consistent gusts in of 20 MPH or more, I doubt the RSO and LCO will allow your L2 cert flight. Keep an eye on the website in the event that the launch is rescheduled for Sunday. The winds are forecasted to be much lighter.

Please Log in or Create an account to join the conversation.

More
6 months 2 weeks ago - 6 months 2 weeks ago #11952 by DeltaVee
Replied by DeltaVee on topic L1 Certification Help

I'm flying on a CTI Pro38-5G J94-P Mellow. Current Sim is actually for 2800ft (I'm updating all my weights tonight to get final numbers).

I have dual-redundant dual deploy using a SLCF and RRC2+. 18in Drogue deployed at Apogee (descent rate of 61 ft/s). I don't deploy my main above 600ft, Saturday I'm thinking 400ft for primary, and 300ft for backup. I wrap the main chute pretty tight, on the test flight the main didn't open until about 150ft after being deployed at 350ft, I'm trying a new method for this flight to avoid that. Main descent rate is 14ft/s, I'd love a smaller main chute but UMass Lowell doesn't have any :/.

I also have a stability of 2.52 (will change with updated weights but not by much) so I will turn into the wind a bit with my 4.3:1 TWR. Using the wind forecast OpenRocket shows me only a few hundred feet from the rail (I saw closer to 400-500ft).

Sim settings are
Wind: 12mph @ 290Deg, deviation of 1.64 mph, turbulance of 13.7%.
Rail: 8ft, 0 degrees (even 5 degrees to the southwest is keeping it before the alpaca pen, ideal would be 2 degrees into the wind but that would be toward the power lines).
Altitude: 2820ft (expecting lower, Higher drag due to flat nosecone, cant on fins, + expected cosine losses from weathercocking)
Max Velocity: 260mph


I also have an eggfinder GPS onboard, just incase.

Your motor selection has a nearly 7 second thrust duration... I would think (with the wind expected) you'll get significant weathercocking... and that could take you all the way to the power lines!  I've seen it happen!  Pointing the rail downwind should help, but you may need more than 5 degrees just to get it to go straight up.  All I'm saying is if it were me, short duration with high avg. thrust rules the day when there is significant wind.

In case you didn't notice, I'm terrified of the wind ;-)
Last edit: 6 months 2 weeks ago by DeltaVee.

Please Log in or Create an account to join the conversation.

More
6 months 2 weeks ago - 6 months 2 weeks ago #11953 by Jbears11
Replied by Jbears11 on topic L1 Certification Help
Don't blame you. I didn't have much of a selection, CTI shortage is really hurting since I don't have AT hardware.

I'll pray for a delay to Sunday, UML is trying to go to a competition that needs an L2 flyer of record. I've flown a few L1's (3 for 4  on L1 flights, only failure was at CMASS in Nov '21, parachute failed to leave body tube). I'm fairly confident I can get L2, but I agree, the winds are really high for Saturday.

Should still be able to get a couple other members to L1, we will have at least 3 L1's to less than 1500ft with JLCRs
Last edit: 6 months 2 weeks ago by Jbears11.

Please Log in or Create an account to join the conversation.

More
6 months 2 weeks ago #11956 by ClaudeMaina
Replied by ClaudeMaina on topic L1 Certification Help
You certainly have set everything up to ensure a successful flight and your new sim altitudes look a lot better. It is really just a matter of the wind and size of the field. My recommendation would be to come early, take your exam and hope that the winds get favorable sometime during the day. I understand that you want a L2 certification for a competition; but IMHO, the goal should be to do everything possible to obtain a certification (any level) on the first attempt. This would include not making an attempt on days when the weather conditions are not optimum. Remember, this is just a hobby. If you don't get your L2 this time around, you will get it the next time around.

Please Log in or Create an account to join the conversation.