2.6" Competitor 2 Stage - Configuration

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markg

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I just finished up my 2.6 Competitor 2 stage built. I'd like a bit of a sanity check to make sure I don't make any stupid mistakes, this is my first 2-stage HPR.

Here is the Openrocket file : View attachment Red Tenacity - 2 stage.ork

I plan to fly it with DMS H550 (0.6s burn time) in booster and a Loki H160-LB (w/pyrodex pellet) in the sustainer. Setup is as follows.

Booster
Eggtimer Quantum #1 (Drogue Channel) - separation charge at 0.7s,
Eggtimer Quantum #1 (Main Channel) - chute deploy at apogee
motor backup @ 7s

Sustainer
- Sustainer ignitor will be handled by Quantum #2 in middle ebay via conduit through MMT centering rings into bottom of motor as per normal launch, wire will be twisted and taped to allow break during drogue deploy
Eggtimer Quantum #2 (Drogue Channel), airstart @ 1s after launch, altitude minimum (none), velocity minimum 100ft/s
Eggtimer Quantum #2 (Main Channel), drogue deploy @ apogee
Eggtimer TRS (Drogue Channel), drogue deploy @ apogee + 1s
Eggtimer TRS (Main Channel), deploy @ 500ft

My sim shows sustainer ignition @ 1s will be at height 156 ft, velocity 216 ft/s.

For pad setup, I'll bring it up to the pad with both ignitors out
- load the booster on the rail, arm the Quantum #1 via wifi and insert motor ignitor
- load the sustainer on the booster (ignitor out)
- arm eggtimer TRS
- insert ignitor in sustainer
- back off, ensure area is clear and arm Quantum #2

Screenshots of the SIM & OR screen showing weights/motor selection.

Simulation.jpg
OR.jpg

Thanks for any help/advice you can offer.

cheers - mark
 
Lots of us are trying to use Eggtimer Quantum’s for staging. Please tell us how it works out.

I don’t have the the manual in front of me right now, but I’m wondering if you can set the minimum altitude to 100 ft. I think the minimum value in the software is 300 ft. (I hope I’m wrong about that.)
 
Lots of us are trying to use Eggtimer Quantum’s for staging. Please tell us how it works out.
I don’t have the the manual in front of me right now, but I’m wondering if you can set the minimum altitude to 100 ft. I think the minimum value in the software is 300 ft. (I hope I’m wrong about that.)

You are correct, I misread the manual. 300ft min, and min speed is 100ft/s change by 100ft/s. I'll edit my first post to reflect these changes.
 
But that creates the problem. According to your simulation plot, you won't be over 300 ft when you want to light the sustainer. I'm having some of the same issues with my simulations and I know one other TRF member here is too. We have both had the sustainer not light because we didn't exceed the minimum altitude for the safety lockout. I want to make this work for MPR and low HPR, but it seems like it's a matter of go big or go home (or build a MD 2-stage rocket that will stage above 300 ft on a G or H motor).
 
But that creates the problem. According to your simulation plot, you won't be over 300 ft when you want to light the sustainer. I'm having some of the same issues with my simulations and I know one other TRF member here is too. We have both had the sustainer not light because we didn't exceed the minimum altitude for the safety lockout. I want to make this work for MPR and low HPR, but it seems like it's a matter of go big or go home (or build a MD 2-stage rocket that will stage above 300 ft on a G or H motor).

Yes, I'll set the altitude minimum to 'OFF' to avoid that problem. It'll still have the velocity check of 100ft/s as a safety. I'd have to bump to booster up to an i500T (380ft) or larger to be able to use the altitude minimum check.
 
Good point. This is one of the cases where it makes sense to only use velocity as the safety lockout.
 
Okay, I put the whole shebang together last night and here is the final setup for flight on Saturday :

Booster
- H550ST, delay 7 seconds
- Quantum Drogue - nose over (1g) for parachute
- Quantum Main - timer - 0.7s (5g) for separation charge

Sustainer
- Loki H160 w/pyrodex pellet, 12 second delay
- TRS Main - 500 ft (1g)
- TRS Drogue - Nose-over + 1s (1g)
- Quantum Drogue - Nose-over (1g), 2 sec pulse
- Quantum Main - air start, timer 0.9s, min velocity 100ft/s, 2 sec pulse

The main only has one charge as the Quantum can't do an altitude release when in airstart mode. I may drop a Quark in there in the future to have a redundant main. The drogue has 3 charges, so that should get out for sure.

If that flight goes well, I'll fly it again on Sunday with an I500/H90Red.

If it doesn't go well I'll delete this post and pretend it never happened :)

cheers - mark
 
Good luck on your project. I haven't studied it in any detail, but I have a couple of comments (if I'm off base, just delete and pretent it never happened).

I think your general timing seems a bit quick. With a motor burn of 0.6 seconds and a separation charge at 0.7, it doesn't seem like it would take much for the two events to overlap. Why not allow a little coast and then also be able to use an altitude check? I'd separate at 1 second and light at 2.

I'm not familiar with the quantum, but why would you use a 2 second pulse? If this is the altimeter latch time, I always try to use the shortest possible time in case the igniter shorts.

I'd put in the booster igniter last.

I would also recommend an all-up test of the electronics before loading the sustainer. With the igniter out and the rocket vertical, turn on all the electronics and make sure the igniter doesn't fire. Turn everything off, load the rocket and go. You want to do everything you can to ensure the sustainer won't fire on the pad, even if you back off before arming the Quantum.

Jim
 
Hi Jim,

Thanks for your comments. I welcome your advice!

I think your general timing seems a bit quick. With a motor burn of 0.6 seconds and a separation charge at 0.7, it doesn't seem like it would take much for the two events to overlap. Why not allow a little coast and then also be able to use an altitude check? I'd separate at 1 second and light at 2.

I reread the Quantum documentation and Cris suggests burn time + 20%, so 0.7 is a little quick. I'll bump it to 1 second. My sim shows velocity at 216ft/s at 1s, 196ft/s at 1.5 and 180ft/s at 2s. I thought it would be best to get the sustainer lit as soon as possible, that's why I set it at 0.9s. I'm also not sure how fast the sustainer will start and get up to pressure, so I figured sooner is better than later?

If I change the sim to 1s separation and 2s ignition, it drops the altitude by about 100ft. I'm not going for altitude, so this doesn't bother me. I just want to make sure the rocket is pointing up when the sustainer lights!

Okay, I ran the sim again. Even if I light at 3s, it is still going 142ft/s, which should still be fine. I'm going to change it to 1s separation, 2s ignition.

I'm not familiar with the quantum, but why would you use a 2 second pulse? If this is the altimeter latch time, I always try to use the shortest possible time in case the igniter shorts.

2 seconds is the default on the Quantum. From the Quantum airstart manual, Cris gives the settings for his flight, he used a pulse time of 4 seconds. Also according to the Quantum manual, it should survive a short from the igniter. I have redundancy on the Drogue and the Main is handled by another computer, so even if the Quantum craps out after sustainer ignition I should be okay.

I'd put in the booster igniter last.
I would also recommend an all-up test of the electronics before loading the sustainer. With the igniter out and the rocket vertical, turn on all the electronics and make sure the igniter doesn't fire. Turn everything off, load the rocket and go. You want to do everything you can to ensure the sustainer won't fire on the pad, even if you back off before arming the Quantum.

Sounds like a good plan, I'll alter my checklist to match.

cheers - mark
 
I'm not sure if you're pyrodex pellet is something you're adding or built into the motor, like CTI. If it's built in, ignition would be fast. If you're adding it, then who knows. Pyrodex pellets burn pretty fast. I don't use them any more, but when I did, I would fill the center hole with epoxy to slow down the burn a little. Now, I use dipped ematches using the PML magnelite. It works quite well.

I see the 1-9 seconds for the firing time. Not sure why that is (maybe Cris can explain the philosophy of that), but I guess it doesn't hurt anything. Just for reference, I typically use 0.1 seconds for ematches.

Jim
 
Success!

First flight was an Aerotech H550ST -> Loki H160 Blue

Booster separation charge was set for 1s, sustainer ignition was set for 2s.

Looking at the video and the data, I'm wondering if it's possible that the separation charge (0.5g) lit the motor? I don't see any slowdown of the sustainer at all, just a steady increase in speed, which matches what I see on the video. I should have increased the samples per second on the Quantum, I had it at the default 20/s. If it wasn't the separation charge, then the igniter/pyrodex just lit the motor really quickly.

In any case, the first flight was a success, apogee 3392ft which is as close as I will ever get to a simulated altitude (3387ft). Both booster and sustainer were easily recovered with no damage. I did lose sight of the sustainer due to the cloud cover but saw it on descent and the TRS tracker had signal as well. Sustainer landed about 1000 ft away from the pad, the booster was reasonably close as well. Booster apogee was 500ft.

(I wish youtube had a vertical video format)

[video=youtube;CWF8kogkVFs]https://www.youtube.com/watch?v=CWF8kogkVFs[/video]

328 (Large).jpg20180421_152902 (Large).jpg
 
Success!

First flight was an Aerotech H550ST -> Loki H160 Blue

Booster separation charge was set for 1s, sustainer ignition was set for 2s.

Looking at the video and the data, I'm wondering if it's possible that the separation charge (0.5g) lit the motor?

Looks like it lit around 1.5 seconds? Maybe the separation charge lit the pellet? Can't say I would have expected that, but maybe it's not that surprising. I always cover the nozzle of the sustainer motor in some way. With larger motors, it's a cap over the nozzle. With CTI motors, I just use the red nozzle cap. Good flight though.

Jim
 
Success!

First flight was an Aerotech H550ST -> Loki H160 Blue

Booster separation charge was set for 1s, sustainer ignition was set for 2s.

Looking at the video and the data, I'm wondering if it's possible that the separation charge (0.5g) lit the motor? I don't see any slowdown of the sustainer at all, just a steady increase in speed, which matches what I see on the video. I should have increased the samples per second on the Quantum, I had it at the default 20/s. If it wasn't the separation charge, then the igniter/pyrodex just lit the motor really quickly.

In any case, the first flight was a success, apogee 3392ft which is as close as I will ever get to a simulated altitude (3387ft). Both booster and sustainer were easily recovered with no damage. I did lose sight of the sustainer due to the cloud cover but saw it on descent and the TRS tracker had signal as well. Sustainer landed about 1000 ft away from the pad, the booster was reasonably close as well. Booster apogee was 500ft.

(I wish youtube had a vertical video format)

[video=youtube;CWF8kogkVFs]https://www.youtube.com/watch?v=CWF8kogkVFs[/video]

View attachment 343243View attachment 343242

Great flight, Mark! Well done, and I was especially impressed with your use of a thorough checklist out at the pads! Congrats on the great flight!
 
Nice flight! To me, it looks like the separation happened about 1/2 second before the sustainer lit... look at 0:03 to 0:04, it looks like the booster separated before the sustainer starts to take off on its own.
 
The second flight didn't go as well.

It was an Aerotech I500ST -> Loki H90Red.

Separation charge @ 1.8s, sustainer ignition @ 2.8s.

From the video and pictures, it looks like it did not separate at 2.8s but held together until the sustainer motor started. It was also weather cocking, so when the sustainer lit it was more horizontal than vertical.

From the pictures it looks like the sustainer finally got lit 8-10 seconds into the flight. It lit just before the booster hit apogee, the pictures my wife took show the booster kicking out it's chute through motor ejection, followed by the backup apogee charge from the quantum - and the sustainer lit and flying away.

I'd already lost sight of the sustainer at that point, and she switched to follow the booster, so I'm not really sure what happened with the sustainer. The booster had an apogee of 2200ft, and fired it's noseover charge at 11.8 seconds.

The sustainer (which probably lit around 2000ft) had an apogee of 2540 and fired it's noseover charge at 13.9 seconds. The sustainer did get it's main out and I saw it land, in about the same spot as the first flight, about 1000 ft from the pad.

The sustainer landed in about the same spot as it's first flight. The drogue chute had a couple of shrouds pulled out, so I'm wondering if it came out when the rocket was moving horizontally or even downwards at a high rate of speed. I didn't download the TRS data yet, but the Quantum data shows apogee at 12.9 seconds, then noseover & drogue fired at 13.9. From 13.25->13.9 the speed goes from -27.64 -> -200.26.

I think I'm going to repeat both flights before I try something new. Before I fly again :

- test lighting the Loki H160/H90 on the ground with the igniter & pyrodex pellet to see how quickly it lights and see if I have to make a change with the igniter
- test the 0.5g separation charge
- cover the bottom of sustainer motor with masking tape to prevent possible lighting of the sustainer by the separation charge (there's no cap or nozzle cover on Loki 38s)
- increase the samples / second on the Quantums to get more data

Here's the photo of the sustainer going and the booster firing it's backup ejection charge :

522.jpg
 
The problem with most red motors is they are prone to chuffing. I’ve encountered it on all my Loki reds and have observed same with AT reds. Really not the best choice for 2nd stage motors.
 
Nice flight! To me, it looks like the separation happened about 1/2 second before the sustainer lit... look at 0:03 to 0:04, it looks like the booster separated before the sustainer starts to take off on its own.

Okay, I went back and checked the original video. There are about 13 or 14 frames between when the separation occurs and the sustainer first shows some smoke. At 30fps, that's 0.5 seconds. It should have coasted for one second.

I pulled the original video into a video editor. Here's what I see :

(2 seconds, 9 frames)
2:09 rocket starts moving
(3 seconds, 17 frames)
3:17 rocket separates (I can hear the separation charge fire shortly after I see it)
(3 seconds, 30 frames)
3:30 sustainer lights

So it seems like either the Sustainer Quantum lit the sustainer motor a little early or the sustainer moter was lit by the separation charge and just took a bit of time to get going.

It seems like the two Quantums were out of sync with their samples, maybe it has something to do with that. For instance :

Booster :
T Alt Veloc FAlt FVeloc LDA
0.45 91 40 67.28 118.58 0
0.5 98 140 73.43 122.86 0
0.55 107 180 80.14 134.29 107

Sustainer:
T Alt Veloc FAlt FVeloc LDA
0.45 111 260 65.3 228.52 111
0.5 122 220 76.64 226.82 0
0.55 127 100 86.71 201.45 0

cheers - mark
 
Yeah, taking 5 seconds to light is not good for a sustainer. I like smokey motors for the sustainer because they light easily and you can see them really well, blues and whites are good too. It looks like your sustainer may have gotten stuck in the transition coupler somehow... I've had that happen, hopefully it didn't cook anything too bad when the motor lit.

As far as the timing difference between the two Quantums, there will be some natural pressure variation and since they're in two different locations on the rocket (one right behind a set of fins...) it's entirely possible that they might not be totally "in sync". That's why I recommend at least a one second difference between separation and lighting the sustainer. You can crank that up an extra half second for a little more insurance.
 
Last night I took apart and cleaned the rocket. The separation charge for the second flight did not go off which explains why there was no separation. The long time to start the motor was because I chose the wrong propellant as timbucktoo wrote. I emailed Scott @ Loki and he said Red was the slowest propellant to light. The order from quickest to slowest - Blue->Cocktail->White->Spitfire->Red.

Also, I used an igniter + pellet to light the motor, I should be using an ematch + pellet, or just an igniter.

I think my first flight was nominal and the blue just lit really quickly. The second flight the red was the wrong choice.

My next chance to fly this as a 2 stage will be at URRF, I'll fly H550ST -> H160, then I500T->H160. If those two work out I'll start moving up the 38mm ladder. At NSL I'm going do some single stage flights so I can test the ematch + pellet start and see how it performs.

cheers - mark
 
I flew this twice at URRF in June. Both times the flights recovered safely, but both had problems. Both were Loki I377CT to H430LB.

First flight (3rd for the rocket) the booster was perfect, sustainer separated but did not light. The Quantum that should have airstarted it thought that it was only at 252ft when the timer went off and so did not light. In reality the rocket was at approx 700ft, so something went funky with the Quantum.

Second flight (4th for the rocket), there was early separation between the sustainer and the booster. The booster was still under power when the sustainer lit. After separation, the booster smacked into the bottom of the sustainer. I don't know what the cause of this was. Possibly another problem with the Quantum, this time early ignition, or the booster motor chuffing causing drag separation.

There was some damage to the I/S coupler, which has been repaired and I'm ready to try again.

The two Quantums have gotten new firmware, and I'm switching the booster motor away from the Cocktail to a Blue instead.
 
I'd like to fly it twice at Midwestpower 2018 next weekend.

Flight #5, I430LB->H160LB
Booster

- Loki I430LB (1.2s burn), delay 10 seconds
- Quantum Drogue - nose over (1g) for parachute
- Quantum Main - timer - 1.8s (0.5g) for separation charge
- Apogee 1250ft
Sustainer
- Loki H160LB w/pyrodex pellet, 12 second delay
- TRS Main - 500 ft (1g)
- TRS Drogue - Nose-over + 1s (1g)
- Quantum Drogue - Nose-over (1g), 2 sec pulse
- Quantum Main - air start, timer 3s, min velocity 100ft/s (anytime), alt 500ft, 2 sec pulse
- Apogee 4590ft

Flight #6, J712LB->I430LB
Booster

- Loki J712LB (1.2s burn), delay 11 seconds
- Quantum Drogue - nose over (1g) for parachute
- Quantum Main - timer - 1.8s (0.5g) for separation charge
- Apogee 2000ft
Sustainer
- Loki I430LB w/pyrodex pellet, 17 second delay
- TRS Main - 700 ft (1g)
- TRS Drogue - Nose-over + 1s (1g)
- Quantum Drogue - Nose-over (1g), 2 sec pulse
- Quantum Main - air start, timer 3.5s, min velocity 200ft/s (anytime), alt 700ft, 2 sec pulse
- Apogee 8729ft

cheers - mark
 
How did your quantum data look in the URRF flights? I had the sustainer not light in one of my recent attempts, and it is apparent from the data that the Quantum didn’t “know” the correct altitude. I’m pretty sure the issue was insufficient vent holes in my AV bay.

Is it safe to say that you simply prefer to use the velocity lock-out over altitude? (I know we discussed this above, but I’m still trying to figure out the best method.)
 
How did your quantum data look in the URRF flights? I had the sustainer not light in one of my recent attempts, and it is apparent from the data that the Quantum didn’t “know” the correct altitude. I’m pretty sure the issue was insufficient vent holes in my AV bay.
Is it safe to say that you simply prefer to use the velocity lock-out over altitude? (I know we discussed this above, but I’m still trying to figure out the best method.)

For my flight, the Quantum data didn't match the TRS that was in the same compartment. It looks like there was a problem with launch detection and noisy data. I have 3x3/32" holes in the sustainer AV bay.

I'm hoping Cris's announcement is going to be something with an accelerometer as I think that would solve an launch detect issues that I think caused my problems.

I'm going to continue to use both velocity and altitude lock-outs, I don't mind the sustainer not lighting if there's a problem, it'll recover safely.

As I said, I've upgraded the firmware on the Quantum and am going to see how it goes next weekend.

cheers - mark
 
I put together a second Eggfinder LCD so I could track both parts. I ordered a Seahorse SE120 case from Amazon, lasercut some 1/8 ply and finished putting it all together today. It's not really done, as I was unable to have separate on/off switches for the LCDs and forgot the balance plug for the battery, but it's good for now.

On the left is the sled I printed for my Eggfinder Mini, it goes into a BT-55 tube and has a loop of kevlar to hang onto a shock cord. That's what I'll hang in the booster. The sustainer has a TRS.

zXV6HjD.jpg
 
Flight #5 - Success! Apogee 4308ft, I430LB->H160LB, settings as in post above. I had an onboard camera but didn't get it turned on, so no video. Here's a shot of the lift off. Everything recovered safely and without damage.

I didn't get a chance to fly it again, so it'll have to wait until the spring for another try at this. Will likely repeat this same flight. I'll also likely swap out the Quantum for the new Eggtimer Proton.

cheers - mark

282746-7dcb46285ae70d78bf16bd2ed51edc89.jpg
 
Here's a copy of my two-stage checklist, recently updated as I replaced the airstart Quantum with a Proton. First two-stage flight with the Proton this weekend at URRF. The Proton has already flown 3 times in single stage mode.

I tried to upload the Excel file but the forum doesn't allow it, so I zipped it up. I'll copy/paste the list below as well.

cheers - mark

Red Tenacity (Two Stage)
AT HOME

Charge Batteries
Assemble Motor(s) as per instructions, use appropriate delay as per sim
Prepare Ejection Charges - 5 x 1g, 1 x 0.5g
AT THE LAUNCH - Booster
Connect 1g apogee charge to bottom of av bay
Connect 0.5g separation charge to Quantum (main)
Connect battery to Quantum (ABA8B3), verify phone can see ie - 192.168.4.1
Check Quantum Status
Insert motor, keep ignitor separate
Pack chute, quicklinks, harness
Tape igniter to body tube
AT THE LAUNCH - Sustainer
Main - connect 1g charge to black terminal (TRS)
Main Backup - connect 1g charge to green terminal (Proton)
Drogue - connect 1g charge to yellow (TRS)
Drogue Backup - connect 1g charge to blue (Proton)
Wrap breakwire around eybolt
Drogue - connect igniter/breakwire to center terminal block (Proton)
Power on Eggfinder LCD, (must be turned on within 45 seconds of TRS)
Plug in batteries for on Eggtimer TRS
Eggtimer TRS check for 1S light flash for GPS fix
Plug in Proton, make sure phone can see it - 192.168.4.1
Check TRS Status on LCD
Check Proton Status
Seal AV Bay
Insert motor, keep airstart igniter separate
Drogue Parachute, quicklinks
Main Parachute, quicklinks
Assemble rocket, insert removeable rivets, shear pins
Set rocket horizontally, calibrate Proton accelerometer
AT THE PAD
Load booster
Load sustainer onto booster (no igniter in motor)
Arm sustainer TRS (Sustainer deployment)
Arm booster Quantum (ABA8B3) (Deployment + Separation)
Insert sustainer igniter into motor
Insert booster igniter
Back off
Check Proton Status (All AQUA)
Arm Sustainer Proton
 

Attachments

  • Checklist - Red Tenacity.zip
    13.9 KB · Views: 18
How did your flight at URRF go?

Nominal. It was a repeat of Flight #5, Loki I430->H160. First two stage flight with the Proton. I didn't download the flight data yet. I had the camera running but it ran out of memory on the pad. Both booster & sustainer were recovered easily from the open field.

cheers - mark
 
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