Magg-nificent two-stage HPR build thread

[jhill9693]

Flight 1 report

SEARS Launch, May 2023

Flew single stage to 2643ft on a CTI J410-11

• Eggtimer Quantum with drogue charge + motor ejection
• Nominal flight and recovery, no weathercocking
• Very straight boost, spectacular red flame
• Easily visible the entire flight
• Nose cone ricocheted and gashed the airframe
• Very gentle touchdown

 

[jhill9693]

Repairs were conducted for the next flight.

Cut out the damaged area with a razor:



Then glued in part of a coupler with Titebond II, and tacked it in place with thin CA:



Finally, glued in a piece of tube to fill the hole:

 

[jhill9693]

Second flight report: ROSCO, June 2023

First two-stage flight on Aerotech J615-4 (aerospike) to I211-10

Eggtimer Quantum, drogue @ burnout + 1s, main @ burnout + 3s

Eggtimer TRS, drogue @ apogee

Jolly Logic Chute Release @ 800ft

• Successful staging with Loudmouth staging igniter from ModelRocketGuy.com
• Altitude 2203ft (predicted 3712ft)
• Top speed 451mph
• Successful recovery under chute

Errors

• Failed to arm TRS due to unused main continuity check failure
• Main chute appeared to release at apogee (forgot to vent airframe)
• Sustainer airframe zippered
• Sustainer failed to reach expected altitude
• Nose cone eye bolt loosened

Despite the failures, it was SO COOL to see that second stage light, and the dark black smoke trail it left behind.

Several forum members got to see it: @cwbullet, @Hobie1dog, @Leo

It coasted a tad too long, which would cost me dearly when I attempted a repeat with an identical config at LDRS.

Thanks Wes Munn for the launch photos!

 

[jhill9693]

Due to the prior repair and the already short length, I opted to cut the airframe and use a coupler to replace the damaged part for LDRS.

Notice the upper airframe vent prominently visible in the un-primed repaired portion.

Thanks @Buddy Michaelson for the photo!

 

[cwbullet]

View attachment 600822

Second flight report: ROSCO, June 2023

First two-stage flight on Aerotech J615-4 (aerospike) to I211-10

Eggtimer Quantum, drogue @ burnout + 1s, main @ burnout + 3s

Eggtimer TRS, drogue @ apogee

Jolly Logic Chute Release @ 800ft

• Successful staging with Loudmouth staging igniter from ModelRocketGuy.com
• Altitude 2203ft (predicted 3712ft)
• Top speed 451mph
• Successful recovery under chute

Errors

• Failed to arm TRS due to unused main continuity check failure
• Main chute appeared to release at apogee (forgot to vent airframe)
• Sustainer airframe zippered
• Sustainer failed to reach expected altitude
• Nose cone eye bolt loosened

Despite the failures, it was SO COOL to see that second stage light, and the dark black smoke trail it left behind.

Several forum members got to see it: @cwbullet, @Hobie1dog, @Leo

It coasted a tad too long, which would cost me dearly when I attempted a repeat with an identical config at LDRS.

Thanks Wes Munn for the launch photos!

Well, that explains the results of the flight. Atleast it lit in the right orientation and survived the flight.

 

[Hobie1dog]

• Failed to arm TRS due to unused main continuity check failure
• Main chute appeared to release at apogee (forgot to vent airframe)
• Sustainer airframe zippered
• Sustainer failed to reach expected altitude
• Nose cone eye bolt loosened

Despite the failures, it was SO COOL to see that second stage light, and the dark black smoke trail it left behind.

Several forum members got to see it: @cwbullet, @Hobie1dog, @Leo

It coasted a tad too long, which would cost me dearly when I attempted a repeat with an identical config at LDRS.

Thanks Wes Munn for the launch photos!






View attachment 600826

That's one sexy eye-bolt, I want those for my L3 rocket, let me know where you got it.

 

[jhill9693]

That's one sexy eye-bolt, I want those for my L3 rocket, let me know where you got it.

They are nice. This was also the cheapest price I could find.

https://e-rigging.com/products/stai...XhQ8WsOgnXV2ms_t2YZNdOOJZ0mJ073BoCG8IQAvD_BwE

 

[Hobie1dog]

That 5/8 x 6 inch long model would have enough length to slide a piece of steel over the bolt section too. Perfect nose weight. I'm looking for a chart that shows how much a certain diameter piece of steel weighs per inch.
found it:
https://blog.thepipingmart.com/weig...Weight Calculation Formula,x 12 / 162 = 4.74.

 

[Leo]

Sure did and loved it

 

[thzero]

View attachment 600822

Ah there is the second stage!

 

[jhill9693]

Third flight report: LDRS 41, day one, July 2023

Same motors and settings as flight #2

• Beautiful liftoff
• Good booster separation, descended under chute
• Booster coupler zippered, tumbled on landing, and popped one epoxy fillet
• Nosed over, sustainer ignition failed
• TRS backup ejection charge failed
• Sustainer came in ballistic
• Total catastrophic loss of sustainer

 

[jhill9693]

It didn't buff out!

But I did manage to salvage three sustainer fins, the 38mm aeropack retainer, motor hardware, recovery system, electronics, and two 1515 rail buttons.

I ordered a replacement nose cone from Chris' Supply, who graciously shipped yesterday morning before leaving for Airfest. It arrived today. Got the RNWS version, which I really like.

Last week, a friend who works in a CNC shop cut some replacement centering rings for me.

Tonight I'm printing a fin alignment guide and backers for the rail buttons.

Commencing re-build in 3, 2, 1...

 

[cwbullet]

It didn't buff out!

But I did manage to salvage three sustainer fins, the 38mm aeropack retainer, motor hardware, recovery system, electronics, and two 1515 rail buttons.

I ordered a replacement nose cone from Chris' Supply, who graciously shipped yesterday morning before leaving for Airfest. It arrived today. Got the RNWS version, which I really like.

Last week, a friend who works in a CNC shop cut some replacement centering rings for me.

Tonight I'm printing a fin alignment guide and backers for the rail buttons.

Commencing re-build in 3, 2, 1...

Every opportunity to rebuild is an opportunity to do it better.

 

[pugachu]

Sorry about your loss. At least the electronics and such were salvageable. Any idea why the failures happened?

 

[jhill9693]

Sorry about your loss. At least the electronics and such were salvageable. Any idea why the failures happened?

Yes. Time to ignition was simply too long. Even though I got away with it the first time, this was at a different site and in different weather. The wind was up, which may have caused some loss of airspeed relative to the first flight. There could also have been some variation in the booster motor thrust. Every burn won't be 100% identical. Whatever it was, it nosed over before the sustainer could ignite. It was not an igniter failure, the Eggtimer Quantum showed "Nose Over" state and the igniter was not burnt.

 

[Leo]

October would be a nice time to give it another try using a new sustainer

 

[OzHybrid]

Yes. Time to ignition was simply too long. Even though I got away with it the first time, this was at a different site and in different weather. The wind was up, which may have caused some loss of airspeed relative to the first flight. There could also have been some variation in the booster motor thrust. Every burn won't be 100% identical. Whatever it was, it nosed over before the sustainer could ignite. It was not an igniter failure, the Eggtimer Quantum showed "Nose Over" state and the igniter was not burnt.

So why didn't you drogue deploy in the sustainer?

 

[jhill9693]

So why didn't you drogue deploy in the sustainer?

It has a drogue chute. I don’t know why the failsafe ejection charge didn’t go off, likely a config error on my part.

 

[OzHybrid]

It has a drogue chute. I don’t know why the failsafe ejection charge didn’t go off, likely a config error on my part.

I can't believe you'd do that.....

 

[jhill9693]

View attachment 601000
I can't believe you'd do that.....

Oof. Well, it actually is rocket science after all!

 

[OzHybrid]

Oof. Well, it actually is rocket science after all!

Good luck with the rebuild.

 

[jhill9693]

The printed and milled parts turned out nice!

 

[jhill9693]

Updated design.

I'm using three CRs this time and .016" wall aluminum tubing as conduit for the forward and aft igniters. Neoprene hole plugs will seal both ends. No charge wells, I prefer using plastic medical sample vials instead. This CRs are too deep in the tube to allow for easy access.

Sleds for the Eggtimer Quasar/Proton and battery will mount directly to the fin tabs. The access panel will be on an opposing side from the rail buttons so that it can be powered on and closed up after it is on the pad.

The RNWS nose allows more room for the recovery system plus space for a tracker bay if needed.

 

[b.wieting]

Very cool rocket and an inspiration! (I'm thinking about 2-stage ideas...).
One suggestion: you might be able to modify the nose cone to build a version of the LOC RNWS. I did that for my old L1 MiniMagg, cutting off the NC base and inserting centering rings, etc. Might hold an EF GPS too.

 

[OzHybrid]

Updated design.

I'm using three CRs this time and .016" wall aluminum tubing as conduit for the forward and aft igniters. Neoprene hole plugs will seal both ends. No charge wells, I prefer using plastic medical sample vials instead. This CRs are too deep in the tube to allow for easy access.

Sleds for the Eggtimer Quasar/Proton and battery will mount directly to the fin tabs. The access panel will be on an opposing side from the rail buttons so that it can be powered on and closed up after it is on the pad.

The RNWS nose allows more room for the recovery system plus space for a tracker bay if needed.

View attachment 601043

With the nosecone, cut a hole on the upperish side of the shoulder to get your eye washer and nut in or the additional nose weight. That way the ejection charge doesn't have to pressurise the nosecone volume too. Or move the top bulkhead further forward and put the chute in the nosecone with an eye further into the nosecone. This moves your cg forward without. any penalty of additional weight

 

[jhill9693]

LOC removable nose weight system going together:



24oz weight cartridge

 

[jhill9693]

Dry fit the fin can:



These neoprene rubber hole stoppers are pretty rad! Might have to enlarge the hole. Gonna make flight prep easier since I don’t have to fidget anymore with mounting putty to seal up the hole.

 

[tsmith1315]

I love the leave-in fin aligners, that's superb!

 

[OzHybrid]

You could easily drill some big holes through those fin tabs and save weight where it's bad weight ie behind your required cg. Same with the alignment jig. Once they're positioned, get rid of it. Bad weight. Same with the middle bulkhead. Have they gotten thicker since the first build?
Make sure those stoppers stay in place or your ejection charge is going straight down that tube, Stage separation could cause that to happen.

 

[jhill9693]

I love the leave-in fin aligners, that's superb!

Thanks! There are some nice parametric fin alignment jigs out on Thingiverse that can be used this way. First time for me: