Lower Altitude Flights for next year
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William Walby
Sep 20, 2022, 1:59:22 PM9/20/22
to ARLISS Flyers
Hi Gang,
I was doing some back of envelope calcs to see if we could get a motor that would give us plenty of rail exit velocity, reasonable acceleration values and still keep us below the 8000ft agl limit that the Military is placing on us during ARLISS. The AT M1600R looks promising.
We no longer need the 12-13k ft that was required when we were flying the original CanSats which required a long hang time to simulate a horizon-to-horizon pass in LEO. So I think that if we keep the flights under 8k ft we would no longer have to shut down when the Fallon NAS wanted to use the MOA . This lower altitude would also benefit the ARLISS Teams due to decrease drift when it is windy.
I would appreciate it if you all would run sims on your rocket with a current LOW using the M1600R vs the M1419 to get and idea of performance across all our rockets. Altitude and max acceleration are the important values.
I’ll put a spread sheet together with everyone’s data and we can discuss.
Feel free to suggest other motors or strategies that would meet these requirements.
Regards,
William
I was doing some back of envelope calcs to see if we could get a motor that would give us plenty of rail exit velocity, reasonable acceleration values and still keep us below the 8000ft agl limit that the Military is placing on us during ARLISS. The AT M1600R looks promising.
We no longer need the 12-13k ft that was required when we were flying the original CanSats which required a long hang time to simulate a horizon-to-horizon pass in LEO. So I think that if we keep the flights under 8k ft we would no longer have to shut down when the Fallon NAS wanted to use the MOA . This lower altitude would also benefit the ARLISS Teams due to decrease drift when it is windy.
I would appreciate it if you all would run sims on your rocket with a current LOW using the M1600R vs the M1419 to get and idea of performance across all our rockets. Altitude and max acceleration are the important values.
I’ll put a spread sheet together with everyone’s data and we can discuss.
Feel free to suggest other motors or strategies that would meet these requirements.
Regards,
William
Jonathan DuBose
Sep 20, 2022, 7:18:58 PM9/20/22
to arliss...@googlegroups.com
But we still fly them to 12k' when no restrictions (military, wind) are in effect, correct?
Does UNISEC say they don't need the original hang time? What has changed?
Jonathan
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Ken Biba
Sep 20, 2022, 8:59:57 PM9/20/22
to arliss...@googlegroups.com
The key issue is what is the new standard for a mission profile. We can always find the right motor.
Have we had this discussion with our international partners?
K
On Sep 20, 2022, at 4:18 PM, 'Jonathan DuBose' via ARLISS Flyers <arliss...@googlegroups.com> wrote:
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Tim Robinson
Sep 20, 2022, 9:00:29 PM9/20/22
to arliss...@googlegroups.com
The OpenRocket model for my Arliss sims out to 11,100' using a 1kg payload (I had flights of 10,950 and 11,500 last week so it's in the ballpark). When I swap out the M1419W and replace with a M1600R, the sim comes in at 9950' so it looks like I'd still be grounded. I'm currently using 10' of effective rail (never measured, just guessed) with M1419 exit velocity is 58 ft/s and with M1600R I see 65 ft/s so that's an improvement. Max acceleration is 6.79G on M1419 and 8.74G on M1600 (for what it's worth I sim to 8.82G max accel on M1340W DMS and altitude 10,600)
Dropping down to 75MM and in DMS, there is the M1350W - I see that sim to 7500' on my airframe and rail exit at 75 ft/s. Max acceleration 8.98G. So that's more in the ballpark for me but would require some 98->75 hardware. This might introduce some geometry concerns since it's a longer motor. It appears to be ok in that regard for my airframe.
Dropping down to 75MM and in DMS, there is the M1350W - I see that sim to 7500' on my airframe and rail exit at 75 ft/s. Max acceleration 8.98G. So that's more in the ballpark for me but would require some 98->75 hardware. This might introduce some geometry concerns since it's a longer motor. It appears to be ok in that regard for my airframe.
-Tim
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William Walby
Sep 21, 2022, 11:10:16 AM9/21/22
to ARLISS Flyers
Haven’t had the discussion yet. I wanted us to come up with some workable alternatives before we present to UNISEC. Having to shut down due to the Military puts undue pressure on both the flyers and Teams. And I don’t see the Military giving us what we need going forward. The Commander of Fallon NAS is of the opinion that any airspace encroachment that is even remotely possible is too big a risk for her comfort.
So please everyone work your sims to help come up with a workable motor option. If we need to go to 75mm it's not that big a task to build a bunch of motor adaptors.
William
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William Kellermann
Sep 21, 2022, 11:34:05 AM9/21/22
to Association of Experimental Rocketry of the Pacific, Inc.
This was addressed at the board meeting. There are multiple options.
One is the suggestion to schedule a meeting with the base commander to see if we can assuage her concerns, but nobody has stepped up to do it.
An alternative is to address the mission and flight profile to fit within the altitude restrictions.
Last, alternative sites for ARLISS were discussed but those proposed were closer to the Reno MOA and thus viewed as untenable.
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William Walby
Sep 21, 2022, 6:55:06 PM9/21/22
to ARLISS Flyers
According to the published guidelines doc on the ARLISS webpage, there is only one section that we specify any altitude at all.
2. All of the launched parts of the UAS should be kept under visual observation during flight. To ensure the UAS is under observation, the UAS must have a GPS with a telemetry system capable of reporting position during the entire flight. AeroPac will launch UASs up to 16,000 ft MSL (12,000’ AGL) and will be deployed up to several miles from the launch site. The UAS must have a telemetry system capable of covering this recovery area.
We state “up to 12K ft AGL” So for the comeback competition we could launch to a lower altitude and still be with in the guidelines as written. We would need to fly ALL the projects to the same altitude in order to make the conditions roughly equal for all teams. I tried to find an official UNISEC rule book for ARLISS but was unsuccessful. YMMV
William
William Walby
Sep 26, 2022, 3:32:10 PM9/26/22
to ARLISS Flyers
Attached is a copy of the most recent UNISEC CanSat Regulations. And as stated below we do not specify a specific altitude for the ARLISS flights. So I do not see an absolute need to continue to fly the student payloads to our usual 12K ft. So I propose we try and find a good solution to fly to 8K ft going forward. But this requires us all to decide on a motor that works for all the rockets. And approval from UNISEC. Will approach UNISEC for approval once we decide on a motor.
Soliciting any and all input.
Thanks
William
Begin forwarded message:
Ken Biba
Sep 27, 2022, 7:14:17 AM9/27/22
to arliss...@googlegroups.com
I think performance will vary based on specs of each airframe. But the M1350 is a good choice.
We can do a buy of adapter hardware.
On Sep 20, 2022, at 9:00 PM, Tim Robinson <timr...@gmail.com> wrote:
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Ken Biba
Sep 27, 2022, 8:25:16 AM9/27/22
to Ken Biba, arliss...@googlegroups.com
FWIW - I suspect I can 3D print adapter components from nylon-cf for a FG tube. I will be flying a 54-75mm version at October Skies.
I will do a set of OR runs to complement Tim’s later today.
On Sep 27, 2022, at 7:14 AM, Ken Biba <ken...@gmail.com> wrote:
I think performance will vary based on specs of each airframe. But the M1350 is a good choice.
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