3 Stage Rocket 🚀 🚀 🚀

[James Kobel]

I’ve been in the hobby for a while now and want to get into staging high power rockets which I have yet to do! I have already designed and bought the body tubes and transitions and nose cone for the project but I’ll need to do a lot of sketching and planning of how to still build this thing. I’m going to take process in steps by first building the sustainer and flying it and then building the second stage and flying it two stage before going onto the full 3 stage rocket. I’m looking at using maybe some Timer 4’s and some egg timer protons for the electronics but I’ll be doing more research on that stuff during the summer when I have more time. This rocket is based on the Black Brant XII (pictured). If you have any tips, advice, or recommendations for me, please feel free to let me know

 

[waltr]

I have done 1 composite 2-stage flight so far. Used eggtimer Quantum for airstart and deploy sustainer chute at nose over. This is minimum required electronics and gets the sustainer's chute out even if motor doesn't light.
Separation was on sustainer ignition and worked fine with no scortching of inter-coupler. Booster chute on motor ejection.
It was build using 2 BMS school rocket kits plus a few extra couplers. Since the BMS tubing is thin for a 3" diameter I doubled the intercoupler and the bottom of the sustainer to ensure the coupling was smooth.
I did a stuff tube so put a hatch for the electonics below the upper CR and build in a bay. then 1/4" tube back through the CR for the motor iginter. BMS sells long lengths of tube.
First flight did work. Second flight is next Saturday.

Download and Read Chris' eggtimer Airstart guide for the Quantum and Proton. He has very good details on what you want to happen and how to figure out timing.
Biggest thing is think, simulate and think some more about what could go wrong.

Your booster's seem large enough to put electronic in them. The 'second stage' will need both airstart and recovery electronics where as the 'first stage' booster only needs recovery.

Apogee Rockets has a video on putting an ebay into the LOC Terrier/Sandhawk. Some good ideas on doing this so worth watching.

Read every post about staging.
Maybe build at least one 2-stage to learn with then this 3-stage.
Later do post the OR file with motors and timing selected for other to check.

 

[James Kobel]

I have done 1 composite 2-stage flight so far. Used eggtimer Quantum for airstart and deploy sustainer chute at nose over. This is minimum required electronics and gets the sustainer's chute out even if motor doesn't light.
Separation was on sustainer ignition and worked fine with no scortching of inter-coupler. Booster chute on motor ejection.
It was build using 2 BMS school rocket kits plus a few extra couplers. Since the BMS tubing is thin for a 3" diameter I doubled the intercoupler and the bottom of the sustainer to ensure the coupling was smooth.
I did a stuff tube so put a hatch for the electonics below the upper CR and build in a bay. then 1/4" tube back through the CR for the motor iginter. BMS sells long lengths of tube.
First flight did work. Second flight is next Saturday.

Download and Read Chris' eggtimer Airstart guide for the Quantum and Proton. He has very good details on what you want to happen and how to figure out timing.
Biggest thing is think, simulate and think some more about what could go wrong.

Your booster's seem large enough to put electronic in them. The 'second stage' will need both airstart and recovery electronics where as the 'first stage' booster only needs recovery.

Apogee Rockets has a video on putting an ebay into the LOC Terrier/Sandhawk. Some good ideas on doing this so worth watching.

Read every post about staging.
Maybe build at least one 2-stage to learn with then this 3-stage.
Later do post the OR file with motors and timing selected for other to check.

Thanks for the response! One concern about mine is not wanting the rocket to airstart the next stage with it being too many degrees of the vertical axis. Is this something that you can do with the Quantum/Proton, having it not light the next stage if it's going too sideways? Otherwise, seems like the Quantums will do the job and save me some money not buying the Protons!

 

[waltr]

Tilt or angle away from vertical is a big concern as to if you want the sustainer motor to light.
The Quantum & Proton can not detect/measure tilt angle due to it only has a barometer chip (Proton has Accelerometer chip but this can not detect tilt in flight). They do have Velocity and/or altitude lock-out.

Read the manuals carefully. They can be downloaded from here:
http://eggtimerrocketry.com/home/support/Cris discusses Airstart issues very well in those manuals.

There is the Tiltometer board that might be able to inhibit airstart on an Eggtimer. Cris at Eggtimer can answer this better.
https://rocket-electronics.com/
Have you done a few rockets with Dual Deploy? If not then you really should start with this to learn the electronic aspect of recovery deployment. Believe me that adding DD adds many more ways a flight can fail.
Multi-stage adds even more ways to fail.

 

[James Kobel]

Tilt or angle away from vertical is a big concern as to if you want the sustainer motor to light.
The Quantum & Proton can not detect/measure tilt angle due to it only has a barometer chip (Proton has Accelerometer chip but this can not detect tilt in flight). They do have Velocity and/or altitude lock-out.

Read the manuals carefully. They can be downloaded from here:
http://eggtimerrocketry.com/home/support/Cris discusses Airstart issues very well in those manuals.

There is the Tiltometer board that might be able to inhibit airstart on an Eggtimer. Cris at Eggtimer can answer this better.
https://rocket-electronics.com/
Have you done a few rockets with Dual Deploy? If not then you really should start with this to learn the electronic aspect of recovery deployment. Believe me that adding DD adds many more ways a flight can fail.
Multi-stage adds even more ways to fail.

Yes. To give ya little more info about me, I am level 2. I have also built about 5 or 6 dual deploy rockets already, and now want to get into staging.

 

[Charles_McG]

Staged Composites is mostly what I've flown the past few years: CPM Scale Sounding Rockets | The Rocketry Forum

I also use the eggtimer products. A GPS Mini in the nose cone of the sustainer. Quantums and Protons for staging. Sometimes a Quark in the booster for deployment redundancy.

The Quantum is smaller. I've squeezed one in an Estes 5560 transition for my Nike Apache - but it wasn't easy. I've wedged a Proton into a Wildchild (about BT60) - but 2" and bigger is -so- much easier.

As Waltr mentions, the Quantum is the practical minimum in capabilities. In airstart mode, the second channel -has- to be the drogue. You could always add a Quark riding along for full dual deploy. The Quantum is purely baro driven, and while the combination of a decent sim, and the altitude and velocity checks at staging time will keep you out of most trouble, it has its limits. Mostly erring on the no-staging side. Your avbay needs to be properly vented - and in such a way that doesn't add error - protruding or shadowed vents can be a problem. It's also slower to respond - so it needs higher staging altitude and coast times to let disturbances settle down. Not huge - but since I fly at Bong (with trees and swamps) I try to fly as -low- as I safely can, and tenths of a second add up fast. Motor burnout and separation cause big baro-altitude swings in my avbays.

I really like the Proton with 6 channels. I like using a tiny separation charge - I just pack the little red cap of an ematch with black powder. I really like the time-after burnout option that the Proton had, rather than the time-after launch detect of the Quantum. The accelerometer based launch detection is quicker, too - 75' isn't hard - or dangerous from the false positive sense. And even adding dual deploy, there are still 2 channels left - perhaps separation and ignition of a middle stage. That's a lot of wiring chases in the top stage, though.

With either, you can add a separate tiltmeter if you think the 'deviation from planned Alt/V' limits aren't enough. Rocket Electronics - home of the RockeTiltometer (rocket-electronics.com)

I'm working my way towards 3 stages. A Black Brant, like yourself, and a Talos Terrier Recruit. But I think my first might be a Nike Nike Cajun. Or maybe I'll cheat and do a mythical Nike Nike Apache.

 

[waltr]

Yes. To give ya little more info about me, I am level 2. I have also built about 5 or 6 dual deploy rockets already, and now want to get into staging.

Ok, that is great. I didn't know your experience so why the suggestions.
Sounds like you are ready for this multi-stage challenge.

Excellent comments Charles.
I fly at a smallish East coast field so also try to fly as low as I safely can. The 2-stage I have stages at about 125' (F67W booster) with sustainer apogee at about 500' (D15T). Hoping to get down to MDRA later this year to fly bigger motors.
I have also kept the sustainer motor small in case it is not vertical upon ignition and doesn't go into the next county as a cruse missile.

Just saw this on the Eggtimer Proto specs: "Barometric vs Accelerometer altitude qualification for off-axis detection ".
This would work by comparing Baro altitude to Integrated acceleration. If not vertical flight then Accel alitude is greater than baro alititude and can disable Airstart.

I would like to build a Scale 2-stage. Nike/Apache or simular. Or maybe a boosted IRIS.
First though is getting my L1 cert (planned for a June launch). Yea, I have been doing DD and airstart on Class 1 rockets. Biggest challenge is fitting the electronics into smaller BT and keeping the weight down.

 

[Charles_McG]

Ok, that is great. I didn't know your experience so why the suggestions.
Sounds like you are ready for this multi-stage challenge.

Excellent comments Charles.
I fly at a smallish East coast field so also try to fly as low as I safely can. The 2-stage I have stages at about 125' (F67W booster) with sustainer apogee at about 500' (D15T). Hoping to get down to MDRA later this year to fly bigger motors.
I have also kept the sustainer motor small in case it is not vertical upon ignition and doesn't go into the next county as a cruse missile.

That sounds pretty challenging. In some ways, higher/faster boost and a 1+ sec coast is easier.
I fly F-H in various combinations. I’m fond of a White Thunder boost to a Mellow sustainer. Like H255 to H53. Boost at about 12Gs comes out pretty straight, even overstable, with apogee at about 3000’, which is the edge of what I can see a 2” rocket. I fire separation at 0.2s and ignition at 0.5s after burnout at about 300'. Faster timing than Cris E suggests. I use pairs of 1/8” polypropylene tubing for wire chases, and I suspect it ports the separation pressure and base drag suction right around the dog barf up to where the avbay can see it. I keep meaning to put a little silicone over the ends of the tubing.

 

[waltr]

Yes, probably be easier with bigger motors but we have lots of tall tree dangling with rockets surrounding our field. Our local club is also restricted to Class 1 rockets. I could run, and may later, run a G76 to D15T for 1000' apogee if wind is very light. This doesn't have DD so Main at apogee.
Altitude and velocity are both too low to use the Quantum's lock outs so this adds another point of things going wrong.
I did think about separation and ignition pressure getting into AV bay, happened on my second DD flight two years ago and triggering Main chute ejection charge at apogee. I plug the tube with igniter leads on the sustainer to prevent this.
The Quantum's data showed no pressure spike at separation so plug worked.

A nice combination I have sim'ed would be an H165R in booster then a G25W in sustainer. Separation at 380', ignition at 500', apogee at 2900'. This would be possible at MRDA's Higg's Farm site (Red Glare site) due to both site size and larger than Class 1 allowed. Maybe in the autumn or next year.

 

[Charles_McG]

Just saw this on the Eggtimer Proto specs: "Barometric vs Accelerometer altitude qualification for off-axis detection ".
This would work by comparing Baro altitude to Integrated acceleration. If not vertical flight then Accel alitude is greater than baro alititude and can disable Airstart.

I just noticed this comment. Yes, it's true, and Cris has put a lot of time and effort in getting both parts right, so they can be compared. I still don't use it - it seems like most of my rockets read baro-alt high, the error increasing with speed. So the Baro-alt is usually above the accel-alt - which shouldn't be possible. But I see it often. If using the feature, I'd fly at least once with the other safety, or tiltometer, or boosted dart to collect real flight data to use to set the deviation limit.

 

[waltr]

Interesting. Only way I can see the baro-Alt going higher is that the air flow down the tube is drawing air out of the av bay through the vent holes. Since the effect is greater with increased speed this is probably what is happening.
Or there is somewhere else the av bay air is being drawn out, maybe through the igniter tube to the base of the rocket.

 

[Charles_McG]

Interesting. Only way I can see the baro-Alt going higher is that the air flow down the tube is drawing air out of the av bay through the vent holes. Since the effect is greater with increased speed this is probably what is happening.
Or there is somewhere else the av bay air is being drawn out, maybe through the igniter tube to the base of the rocket.

I think the prize mostly goes to Mr. Bernoulli. The rockets that show it the worst have 'creative' avbay porting and retention. I noticed that the pressure relief valves built into Rehrig Pacific Pubkey one-way kegs had this cute little caps. Plastic, about 3/8-1/2" OD with two little hooked prongs and a center hole maybe 3/32" across. So I used them as retainer clips on several avbays - 3 around the perimeter. They had rounded tops that sat about 1/8" above the body tube. Velocity dependent alt error. When I ground them closer to flat, it helped. My current avbay design is using 1/4-20 hollow set screws - I can set those flush.

The other design that ran into the issue had a fat payload bay - like the Nike Apache. I think the ports were too close to the transition.

 

[James Kobel]

Staged Composites is mostly what I've flown the past few years: CPM Scale Sounding Rockets | The Rocketry Forum

I also use the eggtimer products. A GPS Mini in the nose cone of the sustainer. Quantums and Protons for staging. Sometimes a Quark in the booster for deployment redundancy.

The Quantum is smaller. I've squeezed one in an Estes 5560 transition for my Nike Apache - but it wasn't easy. I've wedged a Proton into a Wildchild (about BT60) - but 2" and bigger is -so- much easier.

As Waltr mentions, the Quantum is the practical minimum in capabilities. In airstart mode, the second channel -has- to be the drogue. You could always add a Quark riding along for full dual deploy. The Quantum is purely baro driven, and while the combination of a decent sim, and the altitude and velocity checks at staging time will keep you out of most trouble, it has its limits. Mostly erring on the no-staging side. Your avbay needs to be properly vented - and in such a way that doesn't add error - protruding or shadowed vents can be a problem. It's also slower to respond - so it needs higher staging altitude and coast times to let disturbances settle down. Not huge - but since I fly at Bong (with trees and swamps) I try to fly as -low- as I safely can, and tenths of a second add up fast. Motor burnout and separation cause big baro-altitude swings in my avbays.

I really like the Proton with 6 channels. I like using a tiny separation charge - I just pack the little red cap of an ematch with black powder. I really like the time-after burnout option that the Proton had, rather than the time-after launch detect of the Quantum. The accelerometer based launch detection is quicker, too - 75' isn't hard - or dangerous from the false positive sense. And even adding dual deploy, there are still 2 channels left - perhaps separation and ignition of a middle stage. That's a lot of wiring chases in the top stage, though.

With either, you can add a separate tiltmeter if you think the 'deviation from planned Alt/V' limits aren't enough. Rocket Electronics - home of the RockeTiltometer (rocket-electronics.com)

I'm working my way towards 3 stages. A Black Brant, like yourself, and a Talos Terrier Recruit. But I think my first might be a Nike Nike Cajun. Or maybe I'll cheat and do a mythical Nike Nike Apache.

Yea! that is why i am leaning toward using the Proton because 1) It has enough channels to do a staging and dual deploy in one stage and 2) because of the accelerometer based launch detection. One thing I will have to figure out is how to program it to do what I want when I want, but Chris has really good instructions on his website so I'm sure that won't be too much of a hassle.

 

[waltr]

Yes, Cris' instruction for the Quantum and Proto are very good but do require reading and re-reading to go through the options and chose what you want it to do.

He does talk about the issue of doing everything (separation, airstart and Dual Deployment) with one unit. The issue is mainly about when the air frame separates for drogue deployment.

The way I am thinking for my next 2-stage is:
Quark in Booster for chute deployment. Quantum in lower part of sustainer for separation charge and airstart. Then a standard AV Bay for DD using either a Quark or Quantum (or both for redundancy).

The next thing to think about is pad assembly, inserting motor igniters, and sequence of power-up and Arming of the various altimeters.

 

[Charles_McG]

I use pull apart wire connectors.

I never used a formal checklist for single stage flights, but repeated failures ledme to develop one.

Mine has sectios for sim info, including wind and drift estimates, with reminders of where the tree lines are. For prep - including between flight repair plan. And for prep steps at the launch site.

 

[mikec]

I built a three-stage Argo D4 Javelin that was written up in Sport Rocketry a few years ago. I used a single Featherweight Raven in the third stage to control everything. One implication of using only motor eject for the second stage is that if you end up not igniting the second stage, it's most likely going to lawndart. I've had that happen, and I've also gotten lucky and had the second stage dangle from the third by unreleased wiring.

The biggest motor combination I've flown this on is G/G/F, I don't think I would go much larger with this little fault tolerance.

 

[James Kobel]

@waltr @Charles_McG @mikec
One question I just though of is how would the third stage recognize the difference between stage 1 burnout and stage 2 burnout? Or is this done by the qualifications that you can set for velocity@time / altitude@time?

 

[waltr]

@waltr @Charles_McG @mikec
One question I just though of is how would the third stage recognize the difference between stage 1 burnout and stage 2 burnout? Or is this done by the qualifications that you can set for velocity@time / altitude@time?

Depends on which altimeter you use.
A Quantum would be time from lift-off.
Cris only talks about 2-start rocket in the Quantum manual, so maybe not a good choice for the 3-stage sustainer.
The Quantum has no way to detect a burn-out so the timer from Launch detect is all it can use.

"The Proton can sense up to SIX burnouts, so you can trigger on up to six events."
From page 43 of Proton manual.
The Proton has the accelerometer so can detect motor burn-out (acc < 1G).

This can also be qualified with an Altitude and/or velocity checks.

I am not familiar with other altimeter brands. You would need to download their manuals to see to do multi-staging.

 

[mikec]

One question I just though of is how would the third stage recognize the difference between stage 1 burnout and stage 2 burnout?

The Raven has an explicit burnout counter so you simply say "after burnout 2" for the third stage ignition channel, along with any other alt/time gates you might want to use.

 

[James Kobel]

The first I’ll be doing is building the sustainer which I’ll be testing out and getting used to the eggtimer proton

 

[Rocketclar]

Our club has only a 6000' waiver and I, too, like to be able to see my rockets, so I fly my 2-stager to ~3000' on I's to G's. For my very first flight, I prepped everything except putting a motor in the sustainer. I even tested the firing of the firewire in a CTI casing. I use JLCRs on both chutes. The test flight worked great with both parts coming down as planned. JLCRs set at 400'. With my modified Terrier/Sandhawk, the booster typically goes up 1000 to 1500' feet (as determined by the RRC2+ that I use for recovery in the booster.) I do not use motor eject for the booster. I have recently added an Eggtimer Apogee as a backup to the RRC2+. I use a Proton in the sustainer. I do use the deviation between accel and baro, set at 20%. I use two channels to fire 2 drogues, one at apogee, and the other as a backup at apogee +1.3s. So I use a total of 4 charges. I also have an Eggtimer Telemetry module tied to the Proton plus an Eggfinder GPS unit in the NC. I always have a camera on the sustainer looking down. I have put a camera on the booster looking up, but that only showed mostly sky so I quit doing that. Most of the time I haven't been getting drag separation. I did paint the inside of the ISC with high T paint plus I fill it with dog barf and so far it's survived.

 

[Rocketclar]

Also, run lots and lots of sims. I do take Cris' advice and look for a 10:1 thrust ratio. I look to make sure the rocket has enough velocity off the rail for stability, >40mph. And I look at the graphs that Tim at Apogee recommends. I've included a sim graph plus a Proton output summary from my 2-stage flight last Saturday. (Also included is a Quantum output from another flight as I had sent the club the data from both.) Both the Proton and Quantum actual data can be downloaded into a csv file for further processing in Excel. So far, I've just used CTI motors in the sustainer. I've used both AT and CTI in the booster.

 

[James Kobel]

another question I have is have any of y'all used the wifi switch attachment? If so, how did it work for y'all? That's something that i am really leaning toward getting when I get my protons.

 

[Rocketclar]

Make sure you have the wifi passcode readily available. Essentially every time I try to access (either Protons or Quantums) in the field, I have to "forget the network" and relog onto it. Then open an incognito page and type in the access address. If you have continuity everywhere you're suppose to, then you can arm it with a code that changes periodically. Only big problem I have is trying to read my phone's screen in the sun.

 

[waltr]

I like the feature on the Quantum.
I wrote the WiFi passwords in the back of my launch log book so have it if needed.

I do recommend going into the setup (IP 192.168.4.1/setup) and change the device name. For example "QAUN_IRIS_WR" which is a Quantum device in my IRIS scale rocket and wr is my initials. This makes the 'network' name easy to recognize and connect to.
This will be unique at a large launch.

So far both Quantums I have worked perfectly. I expect the Proton to be the same.
The circuit and Arm code Cris uses has been approved by Tripole to be powered on while rocket is not on the rail. Then enter code and Arm once rocket is ready to go. It is great for big rockets and Arming can be done from the ground and a safer distance (no arming on a ladder).

 

[Charles_McG]

I also trust the isolation built into the Quantum and Proton, and don't double up with other switches, wifi or other otherwise. I -DO- follow the practice of doing the initial continuity test without powder. Also, all my powder charges are pretty small.

I have the sustainer igniter wired up at home, but I tape it to a fin until it's on the rail and pointed away from people.

I damaged a Quark during construction in a way that made it fire one channel immediately and continuously upon powerup. I traced it back to the processor - but ended up trashing that one and moving on. Now I always do the first channel test with christmas lights.

 

[waltr]

I have the sustainer igniter wired up at home, but I tape it to a fin until it's on the rail and pointed away from people.
I damaged a Quark during construction in a way that made it fire one channel immediately and continuously upon powerup. I traced it back to the processor - but ended up trashing that one and moving on. Now I always do the first channel test with christmas lights.

I also have the sustainer igniter wired in at home. It does not get inserted into motor until rocket is on the rail and continuity check passes.

Another person in my club had a Quark that never quite worked right then fired the ematches upon checking continuity. It is removed from service now and he is giving it to me. I am just curious as to what when bad.

Oh, yes, xmass tree lights are great and the best way to do initial testing.

 

[Jack Hydrazine]

I built a three-stage Argo D4 Javelin that was written up in Sport Rocketry a few years ago. I used a single Featherweight Raven in the third stage to control everything. One implication of using only motor eject for the second stage is that if you end up not igniting the second stage, it's most likely going to lawndart. I've had that happen, and I've also gotten lucky and had the second stage dangle from the third by unreleased wiring.

The biggest motor combination I've flown this on is G/G/F, I don't think I would go much larger with this little fault tolerance.

Do you happen to have a RockSim of your Javelin model? Thanks.

-JH

 

[James Kobel]

View attachment IMG_3375.mov
This thread has not been abandoned!!! School been real busy but this summer my goal to build at least the 3rd stage (the black Brant part). My friend and I just attempted the G-staging record for Tripoli and I think I’m now addicted to staging and have been motivate to get this one going!