L2 Recovery Options

[DaHabes]

I just completed my L1 cert with a Madcow Super DX3, single deploy, motor ejection. I put they main where the drogue would go on a DD setup and kept the NC on with shear pins.

I have up to this point planned on using the same rocket for my L2, full dual deploy with an AV bay, redundant altimeters, drogue and main.

Now that I am thinking about it further I would like some feedback on different recovery options.

Option 1 - motor ejection, drogue-less recovery with a JLCR on the main. Sims out to about 4,000 feet and change on a baby J.

Option 2 - Full DD with the AV bay setup noted above.

Option 3 - I thought of this option but am unsure of the viability. I'm not entirely comfortable with drogue-less (Option 1) having never done it. I used the braided three loop kevlar shock cord from Rocketman, main on the middle loop, for my L1, motor ejection at apogee. Here is it my question. Is it feasible to used a large streamer as the drogue to control initial descent with a JLCR on the main? The streamer would be attached to the NC, the main to the middle loop. Would that config be problematic from an entanglement standpoint? Another option would be to put the streamer on the middle loop and the main (with JLCR) attached to the NC using a shorter individual shock cord. That would position the main away from the streamer rather than directly beneath it.

I will do full-on DD with an AV bay in the future, a must for L3. With either options 1 or 3 I can go for my L2 this winter/spring. If I do a full on AV bay, given the challenges of finding viable launch windows in the Midwest corn fields, it would be late 2020 or 2021 before I can even attempt it, given build and testing requirements preceding the L2 cert attempt.

Thanks in advance...

 

[Nytrunner]

Option 3 is quite viable.
Our prefect attaches the cuhute release to the mouth of his main, and lets the rest of the main flap up like a steamer.

That being said, why rush to L2? Lots of good L1 motors to experiment with and learn on. Slow is smooth, smooth is fast as they say

 

[spigalau]

If using a streamer, keep in mind that it can have a negative impact on your main chute opening speed. We had a 1/4 scale patriot come in 'warm' last month under streamer as the main chute (rocketman) did not fully inflate. Rocket hit the ground under accelerated conditions but was slow enough not to cause any damage.

 

[David Schwantz]

Did my L2 with a JLCR, J250. Recovered great, other than wind dragging it across field. got some wear marks on fins.

 

[DaHabes]

Option 3 is quite viable.
Our prefect attaches the cuhute release to the mouth of his main, and lets the rest of the main flap up like a steamer.

That being said, why rush to L2? Lots of good L1 motors to experiment with and learn on. Slow is smooth, smooth is fast as they say

No rush, per se, other than I'm 65, I've been doing this hobby for over 55 years and need new challenges, we're traveling a lot while we can still walk, we have four grandkids that live 1000 miles away, so we travel even more. We hike a lot, we bike a lot. Plus, limited HPR options during the summer months (corn fields). Hard to fit hobbies in (I also do astronomy). There are only so many weekends in the year (52 last time I counted). Who knew retirement was so busy?

 

[DaHabes]

I would size the streamer via sim to come down at around 80 fps, JLCR at 700-800 feet. Then again, maybe I'll go drouge-less. I have three clubs I'm starting to fly with, will ask the vets their opinions as well...

 

[richP]

I can only speak for myself, but found that if considering doing L3 in the future, you might as well do full DD now and get some experience with it. Classic DD with motor back-up for drogue shouldn't take too long to set-up with your platform.
Keep in mind that you don't "need" dual altimeters, but you could always add an additional charge cup for the main on an RRC3 aux channel for backup if you feel the need.

 

[MikeyDSlagle]

So you're retired; and travel a lot; and won't have a place to launch until late 2020? Sir...just travel to somewhere and fly.

I for one don't trust motor eject. If I can get electronics in a rocket I will; to control apogee deployment that is. Dual deploy isn't difficult, or scary. And now you can buy a printed sled, switches, charge wells and the works commercially made, add all-thread, a coupler and machined bulkheads, nothing to it. I've had less failures, zero, with full DD than with JLCR, three (one was admittedly my fault). And one failed electronic apogee deployment resulting in a lawn dart, rocket was undamaged. I have had four incidents with delays. Two resulted in damaged but easily fixed body tubes; the other two the rockets burnt up after barely leaving the ground, one is being repaired, the other was trashed.

I've flown a drogue twice and it tangled both times. That is not normal though, many fly drogues successfully, think it was my choice of drogue. I go drogueless. The DX3 looks to be a good candidate for drogueless. The bundled main will offer some drag and slow the rocket a bit. My Ethos came in under a bundled main at 51 fps. My L1 rocket, Danger Close, is a 2.6" glass weighing around 4lbs. It is DD and drogueless, initial descent is 72 fps. My 4" Cowabunga, Wastelander, weighs significantly less than Ethos and also falls at 51 fps under a bundled main. All data is from my Altimeter 3.

No experience with streamers on HPR.

The more blankets, strings, tethers, lanyards or whatever you have on one section of harness, the more chance to tangle.

If you're comfortable with motor eject, then set it up just like your L1 flight and just add the JLCR to the bundled main.

 

[jjwb22101]

A few thoughts: On a small J motor, the DX3 will probably go somewhere in the high 2,000' to low 3,000' range, depending on how it's built, which may be recoverable (esp. on the low end) without dual-deploy of any sort, just running motor eject. However, I'm guessing, based on your question, that your field isn't necessarily large enough for that. In that case, I'd recommend getting some experience with some larger L1 motors flying full dual-deploy on that rocket, then using a standard dual-deploy configuration (Option 2) for your L2 flight. I've seen a lot of cert flights with JLCR's fail without any discernible cause - either the parachute slips out of the release at apogee and you end up with a rocket in a tree, or the release never actually opens (saw an L1 cert attempt fail last weekend due to that).

While it's true that there's probably similar failure rates between cert attempts using a JLCR and cert attempts using conventional dual deploy (I don't have a large enough sample size to say with much certainty, but in my experience it's been pretty similar), those individuals using a JLCR for their cert are almost always much more experienced with them than the conventional dual-deploy people are with their deployment scheme. It also seems that familiarity and experience with the JLCR doesn't dramatically improve the odds of a successful certification flight, but with conventional dual-deploy, those people who have done it before are much more likely to succeed.

With all of that said, my general recommendation for all cert flights is that you should do what you know how to do, not be trying to learn things on that flight. I wouldn't recommend using dual-deploy of any kind (conventional or JLCR) for the first time on a cert flight - that's how most people end up failing their certs, they'll forget something basic but crucial when putting it all together, and the parachutes don't end up deploying right (you'd be shocked at how many people forget to turn on their altimeters). Get some experience with both the JLCR and a more conventional dual-deploy config, and then decide what you're more comfortable with using for your L2. Best of luck!

 

[Chad]

I did my L2 with a 4" cardboard super dx3 on a AT J250 single-use motor. I used dual deployment with a StratologgerCF on factory default settings with motor eject as backup. It flew to 3,700 feet with the main deploying at 700'. I picked it up maybe 200 yards from the launch pad. It went pretty much perfectly.

Make sure you ground test the ejection charges.

Also, make a check list because you're going to be nervous at the field and definitely at the rail, a checklist is vital.

 

[Mrgbus]

I was wondering, if I'm using dual deployment do I install the delay element into my plugged forward closure?

 

[BeyondEarth]

@Mrgbus you can purchase a "Forward Plugged Closure" for Aerotech hardware or use the delay element and no BP, but I've seen someone just fill it with some superlube, sometimes with a solid paper disk as well. If you have a spare closure you can epoxy it closed.
I just purchased the forward plugged closures I needed.

 

[DaHabes]

A few thoughts: On a small J motor, the DX3 will probably go somewhere in the high 2,000' to low 3,000' range, depending on how it's built, which may be recoverable (esp. on the low end) without dual-deploy of any sort, just running motor eject. However, I'm guessing, based on your question, that your field isn't necessarily large enough for that. In that case, I'd recommend getting some experience with some larger L1 motors flying full dual-deploy on that rocket, then using a standard dual-deploy configuration (Option 2) for your L2 flight. I've seen a lot of cert flights with JLCR's fail without any discernible cause - either the parachute slips out of the release at apogee and you end up with a rocket in a tree, or the release never actually opens (saw an L1 cert attempt fail last weekend due to that).

While it's true that there's probably similar failure rates between cert attempts using a JLCR and cert attempts using conventional dual deploy (I don't have a large enough sample size to say with much certainty, but in my experience it's been pretty similar), those individuals using a JLCR for their cert are almost always much more experienced with them than the conventional dual-deploy people are with their deployment scheme. It also seems that familiarity and experience with the JLCR doesn't dramatically improve the odds of a successful certification flight, but with conventional dual-deploy, those people who have done it before are much more likely to succeed.

With all of that said, my general recommendation for all cert flights is that you should do what you know how to do, not be trying to learn things on that flight. I wouldn't recommend using dual-deploy of any kind (conventional or JLCR) for the first time on a cert flight - that's how most people end up failing their certs, they'll forget something basic but crucial when putting it all together, and the parachutes don't end up deploying right (you'd be shocked at how many people forget to turn on their altimeters). Get some experience with both the JLCR and a more conventional dual-deploy config, and then decide what you're more comfortable with using for your L2. Best of luck!

Thanks for the input. I intend to either do plenty of JLCR flights or do full DD on L1 engine(s) before I do an L2 cert flight. I'm going to start my DD AV Bay build this winter regardless, so I'll likely test out both and then decide. It's nice to have options, depending on field size, wind conditions, etc.

 

[tOD]

I did my L2 with a 4" cardboard super dx3 on a AT J250 single-use motor. I used dual deployment with a StratologgerCF on factory default settings with motor eject as backup. It flew to 3,700 feet with the main deploying at 700'. I picked it up maybe 200 yards from the launch pad. It went pretty much perfectly.

Make sure you ground test the ejection charges.

Also, make a check list because you're going to be nervous at the field and definitely at the rail, a checklist is vital.

My L2 was almost a carbon copy of Chad's. DX3, one altimeter, motor backup. My motor was a J350 in the AT 720 case. I think you can be successful without the redundant electronics. As a matter of fact the more complex set-up could trip you up without sufficient practice. I used the same altimeter, didn't even have a switch, used "twist and tape". Tried to make it as simple as possible. Building my first fully redundant setup now. Hoping to fly it in the spring; will be driving 5 hours to find a field with enough space. Maybe my first "K" motor.

 

[Mrgbus]

@Mrgbus you can purchase a "Forward Plugged Closure" for Aerotech hardware or use the delay element and no BP, but I've seen someone just fill it with some superlube, sometimes with a solid paper disk as well. If you have a spare closure you can epoxy it closed.
I just purchased the forward plugged closures I needed.

I too purchased the forward plugged closure. My question, do I still put the delay element inside the forward closure?

 

[Wallace]

No rush, per se, other than I'm 65, I've been doing this hobby for over 55 years and need new challenges, we're traveling a lot while we can still walk, we have four grandkids that live 1000 miles away, so we travel even more. We hike a lot, we bike a lot. Plus, limited HPR options during the summer months (corn fields). Hard to fit hobbies in (I also do astronomy). There are only so many weekends in the year (52 last time I counted). Who knew retirement was so busy?

I'd say if you've been in the hobby for 55 years, ain't it about time to dive into dual deployment? It's not THAT difficult, you just need to be meticulous in your design and setup. Ground testing is not only important but also a fun learning experience. I full on vote dual deploy.Once you've done it ,you'll find it at least, if not more enjoyable than the 'ol "up part"...

 

[David Schwantz]

Yes, I put the delay in as it is also tracking smoke after burnout.

 

[Wallace]

I personally get more excitement/satisfaction out of my successful dual deployment "schemes" than I do out of making a rocket go up. Obviously you already know how to make that part happen.

 

[Steveo]

I flew my rocket 3 times with DD before I loaded a J357 and went for my Level 2. Got my method down so I wasn’t so anxious with the certification flight. I also use a JLCR on another rocket but DD has been a lot of fun.

 

[Dustin Lobner]

I flew both my L1 ad L2 on the same rocket, motor deploy for both. I had a JLCR available, but figured there's enough going on for a cert attempt and I figured simplicity was a virtue. Had to walk a quarter mile to get the rocket, but worth it. Just my $.02

 

[John Williams]

So for my level 1 flight and two other flights that day what I did was put the chute release around the main and then a littles ways down the shock cord I attached a small drogue chute that opened ilas soon as it was ejected then the main opened at 600 feet when the chute release opened did it three times at Midwest power and it was successful all three times

 

[AfterBurners]

Did my L2 with a JLCR, J250. Recovered great, other than wind dragging it across field. got some wear marks on fins.

Probably a chutes with a spill hole would probably allow it to deflate when it lands

 

[David Schwantz]

Maybe, we launched between gusts

 

[Wallace]

https://www.windy.com/?43.621,-87.116,8

 

[SammyD]

Dual Deploy is the way to go - too much variation in the delay times with delay elements in my opinion. There's also the satisfaction of putting together an AV Bay, orienting the electronics, batteries, etc. and making it all work together in something you built.

Ground testing is key to being sure the system works PRIOR to flight. Any way you go, however, is always a learning experience and fun. Just enjoy the experimentation

 

[Flyfalcons]

Go for dual deploy. It's very satisfying to watch it work.

 

[John Taylor]

I second the statement about doing what you are comfortable with. Keep it as simple as possible. Get daring and add new things and complexity after you get your certification. Blow it out out at the top if you can safely recover it. Get your delay time right for sure though.

 

[Andrew_ASC]

I’m personally going full dual deploy option 2 on my L2 build a 54mm Min diameter. Haven’t quite finished it yet. Been meaning to fly it this year or next. All I really got left to do is get a laptop and internet set up then finish the av bay and programming of said devices.

Chute release etc is fine. I just want to do a traditional dual deploy rocket and learn the ropes of that. My last multistage experience w/ university single deploy at apogee had 1.4 mile wind drift at 11,500ft. I’ve been seeing wind drift of certain dual deploy min diameters do 1/4-1/2 mile drift for 22000ft plus.

 

[beeblebrox]

I’m personally going full dual deploy option 2 on my L2 build a 54mm Min diameter. Haven’t quite finished it yet. Been meaning to fly it this year or next. All I really got left to do is get a laptop and internet set up then finish the av bay and programming of said devices.

Chute release etc is fine. I just want to do a traditional dual deploy rocket and learn the ropes of that. My last multistage experience w/ university single deploy at apogee had 1.4 mile wind drift at 11,500ft. I’ve been seeing wind drift of certain dual deploy min diameters do 1/4-1/2 mile drift for 22000ft plus.

Going minimum diameter on a cert flight is a very bad idea. Use something that will work easily, go low altitude and recover. The rocket needs to be inspected after the flight as well to determine if it can fly again. Get your certification first, then go for your minimum dia. project. Use a 10 lb rocket with a low J. Dual deploy is good for that too. I have seen too many people not get certified due to going for broke...

Remember the KISS rule, AND Mr Murphy is out to get you...lol

 

[Mrgbus]

Yes, I put the delay in as it is also tracking smoke after burnout.

Thanks David, will do.