Help on selecting a first two stage high power rocket kit

ksaves2 said:

I'm sure the folks who've stood next to a very large rocket to arm the ignition electronics would enjoy the peace of mind of being able to put some distance between them and the project on the pad. Kurt

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Yes they would. The WiFi switch appears to work through the carbon with good range. More testing needed, but this is really good! Thanks for prodding Kurt.

Jim

JimJarvis50 said:

Yes they would. The WiFi switch appears to work through the carbon with good range. More testing needed, but this is really good! Thanks for prodding Kurt.

Jim

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Jim,

Can you use the WiFi switch to shunt or as an inline switch on the sustainer motor? Last I checked that was not possible because it was designed to pass through battery connections. To my knowledge it does not provide connections for other things like an inline switch on the sustainer motor.

Wayco said:

Nate, The Wifi switch has to use battery power to function. I'm no schematics expert, but I don't think it will work as a shunt or inline to the sustainer igniter.
I'm building one now for my RRC-3 that is programmed to light the sustainer motor in a 3" Wildman rocket CJ built and sold to me a couple of years ago. This thread has inspired me to add some avionics to it and fly it at Airfest this year. Chris Erving thinks I should use a Quantum for the airstart, but CJ will be at Airfest and has plenty of experience programming the RRC-3 for this purpose. I recently built a Quantum, but Sharon stole it for one of her rockets. I will probably build another as a backup altimeter in the 3" sustainer, but since I haven't flown one yet, I'm hesitant to use one as primary.

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The wifi switch could be wired to control a high current (automotive) relay for use as a shunt. Using the normally closed contacts on the relay as the shunt would result in the shunt being in place right up to the time the switch were activated and would leave the shunt in place through a power failure to the switch.

Wayco said:

Nate, The Wifi switch has to use battery power to function. I'm no schematics expert, but I don't think it will work as a shunt or inline to the sustainer igniter.
I'm building one now for my RRC-3 that is programmed to light the sustainer motor in a 3" Wildman rocket CJ built and sold to me a couple of years ago. This thread has inspired me to add some avionics to it and fly it at Airfest this year. Chris Erving thinks I should use a Quantum for the airstart, but CJ will be at Airfest and has plenty of experience programming the RRC-3 for this purpose. I recently built a Quantum, but Sharon stole it for one of her rockets. I will probably build another as a backup altimeter in the 3" sustainer, but since I haven't flown one yet, I'm hesitant to use one as primary.

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I agree with your statement. What I am saying is that it would be more practical if it functioned like a true switch. Right now, the switch is Battery +/- in and battery +/- out. This works great for anywhere you need to switch power and not at all anywhere you want standard switch functionality to break a connection.

I would like to see the WiFi switch have battery +/- in and 2 switch inputs. Then, when the wifi switch is enabled, the circuitry closes the connection between the 2 switch inputs just like a physical switch would. That way, you can enable it to function like an arming switch for a sustainer motor. Now, Steve is right in that you can use the current switch in conjunction with a relay to get this functionality, but I would like to see it built in.

NateLowrie said:

Now, Steve is right in that you can use the current switch in conjunction with a relay to get this functionality, but I would like to see it built in.

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For what it's worth, years ago, I used a Gwiz MC2 to do the altitude check function for staging (prior to the Raven and the others that can do it now). The MC2, as well as the ARTS II, had the capability to fire a channel on the way up at a specified altitude. I attached a transistor to the output of that, and then the signal from the altimeter would open the gate for the timer to light the sustainer.l If the gate was open when the timer fired, then the sustainer would light. It worked quite well and was very simple. The Wifi switch could be used in place of the altimeter, and then it could function as a switch instead of just passing along the battery.

Jim

JimJarvis50 said:

For what it's worth, years ago, I used a Gwiz MC2 to do the altitude check function for staging (prior to the Raven and the others that can do it now). The MC2, as well as the ARTS II, had the capability to fire a channel on the way up at a specified altitude. I attached a transistor to the output of that, and then the signal from the altimeter would open the gate for the timer to light the sustainer.l If the gate was open when the timer fired, then the sustainer would light. It worked quite well and was very simple. The Wifi switch could be used in place of the altimeter, and then it could function as a switch instead of just passing along the battery.

Jim

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Nice, what did you use for the timer?


Steve Shannon

Steve Shannon said:

Nice, what did you use for the timer?


Steve Shannon

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I just use the Perfectflight timers - the older ones. And only 9 volts for the batteries. It might work fine for other batteries, but I never tested other than 9 volts.

I also used solid state relays as part of my vertical stabilization system, but there turned out to be a better way to solve the specific problem we had, so this was short-lived.

Jim

Hi Jim,

Would you just use a main Chute at apogee for the 3" Wildman booster section? Do you utilize another method to utilize two Chutes, a drouge at apogee and a main Chute at a lower altitude when you only have one airframe separation on the booster?

Thanks,
Bob

Bobfly said:

Hi Jim,

Would you just use a main Chute at apogee for the 3" Wildman booster section? Do you utilize another method to utilize two Chutes, a drouge at apogee and a main Chute at a lower altitude when you only have one airframe separation on the booster?

Thanks,
Bob

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My older 3" two-stager is just motor deploy of the main at apogee. On higher flights, I put a tracker on it. The next time I fly it, I will probably try a chute release, although with motor deploy, and likely higher-velocity deployment, I would expect the main to escape the chute release a fair fraction of the time. Better would be to modify it for electronic apogee combined with a chute release. I'd do that if the rocket had a little more life left in it.

All of the other two stagers have conventional, zipperless, dual-deploy configurations with a tube break at the apogee point only (but not at the altimeter bay).

Jim

Bobfly said:

Hi Jim,

Would you just use a main Chute at apogee for the 3" Wildman booster section? Do you utilize another method to utilize two Chutes, a drouge at apogee and a main Chute at a lower altitude when you only have one airframe separation on the booster?

Thanks,
Bob

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My first 2-stage was a Wildman-3, which I think 3in dam. is perfect for learning. Big enough to work with many size motor combo's and plenty of room for electronics.

For me when starting, keeping things a simple as possible is a must. The less you have to figure out the better, till you grasp the needed skills for larger motors and staging delays. 2stagers are way more complex than 2x's a normal rocket.

My first 2 stage was the proto-type and Tim and I, flew the maiden flight in a drag race....those were the days!


I would use a small simple altimeter, just for apogee deploy only, on booster, rather than counting on motor delay ejection.
Add to that a simple accelerometer based unit, to fire separation charge "at burnout".

I use a Strato CF or Missleworks RRC2+ for apogee deploy. The I use 2 e-matches in one charge for my "redundancy". I still use motor eject but no longer adjust delay...it a back-up...back-up.
Pet 2 timer for seperation.
There are so many electronic out there now, the Eggie thingies that do many things. Sorry I don't know the versions, I just know many folks are happy with them. Ravens -Marsa- Adept among many make capable electronics it's just about how much are you willing to "risk" at first.

I use as small a chute possible, depending on burn out weight of booster for safe recovery.
The Wildman is very sturdy when built according to instruction and take a lot of abuse, so bring it down fast as possible for your flying condition and field type.

Eventually most will desire to fly the biggest thing that will fit and that means many big K's & small L's have plugged motors, so electronic deployment is a must.

So all the above removes many obstacles you will need to figure out. No staging delay to start....just getting everything to just work....is an accomplishment in itself.

No need for dual deploy on booster, especially when starting out. Concentrate your efforts on a smooth near perfect fit of I/S [interstage coupler] between both booster/sustainer so your stack has a little of wobble as possible. One of the most important & overlooked facets of flying these these things. The less joints in the stack...the better.

When fully built and assembled get someone on a ladder. holding tip of NC.
Then right above sustainer fins "push" the rocket back and forth to see how play is in the stack. You don't want a Banana...LOL More on that later on. Just be sure to fit vent bands and couplers, so every joint is square and true. It all matters so much more than a normal rocket.......as you will see!

Good luck, have fun & be safe....very, very safe. There is NO second chance when things go wrong with a 2-stage. I cannot emphasize this enough. It now becomes YOUR responsibility for flight/ground safety of all around you.:smile:

Been reading this thread from the beginning. I kinda want to build a two-stage now.

Scratch build. The difficulty is NOT in the rocket construction, it's in the configuration of the electronics with proper safeties in place to ensure a safe flight profile.

patelldp said:

Scratch build. The difficulty is NOT in the rocket construction, it's in the configuration of the electronics with proper safeties in place to ensure a safe flight profile.

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This is what I believe also, and is why I bought one of CJ's 2 stage, 3" rockets. I have accumulated parts for another 2 stage, with a modified 3" Punisher as the sustainer, and a minimum diameter 3" booster. First, I want to work out the electronics with CJ's rocket. As of now, I have an RRC-3 with an Eggtimer Wifi switch and an Eggtimer Quantum for redundant dual deploy in the sustainer avbay.
This will allow me to arm the altimeters with my Iphone from a safe distance away, instead of 10 ft. up on a ladder. The RRC-3 will do the airstart, at least until I get more familiar with the Quantum, then that might change. I also put an Eggfinder in the N/C.
The booster interstage coupler has a PET2+ timer set to fire the separation charge 1 second after MECO, and a Perfectflite SLCF. Since I'm planning on using a much larger booster motor on my minimum diameter build, I decided to use a cable cutter dual deploy method for CJ's rocket also. First flight on the K2050 Super thunder will probably only take the booster to 2000 ft. , but it will give me a chance to watch the booster deploy. Well, maybe not, I'm probably gonna be watching to see if the sustainer will airstart, but if the booster is recovered, I can figure out what happened later.
Since the rocket is a proven flier, I can concentrate on making the electronics work before I build my own 2 stage rocket. First flight is planned for next months Airfest launch, on the aforementioned K2050 Super thunder booster, and a CTI K160 classic longburn in the sustainer. Sims to 11,220 ft. and my good buddy CJ promised to supervise, and laugh at me when I mess up.

Thanks Crazy Jim and all of the other new contributors to this thread. Crazy Jim you added a lot of information in your post. Based on your advice I am going to skip dual deployment on the booster for now. The 3" Wildman kit that I am building is really just a testbed to get all of the two stage electronics and staging to work. I will be trying to use the lowest power motors that are safe to keep the altitude low.

I will use an altimeter in the booster to deploy a main Chute at apogee. The motor ejection charge can serve as a backup in the booster. Some people are firing the small seperation charge from the sustainer as well as the sustainer ignition. What do you think?

Are you running your two ematches into the one ejection charge on a single altimeter output or two altimeter outputs?

When you you talk about a tight fit on the rockets joints like the interstage, you mention a shake test, what are you using to tighten up the connection if it is a little loose? Simple tape?

Too bad that there isn't more usable AV Bay space in the 3" rockets. It's hard to fit two redundant altimeters in a 3" Bay. I am planning on using Vern's new staging altimeter that links to his Kate unit for the sustainer operations.

On another safety topic. I have not seen anyone launch a two stage rocket at any of the club launches that I have attended. We all install the igniters on the pad for safety with the single stage rockets. Where are you two stage rocketeers installing the igniter on your sustainer? Do you ask the RSO for a designated area away from the flight line, cars, and launch pads?

Bobfly said:

1. Thanks Crazy Jim and all of the other new contributors to this thread. Crazy Jim you added a lot of information in your post. Based on your advice I am going to skip dual deployment on the booster for now. The 3" Wildman kit that I am building is really just a testbed to get all of the two stage electronics and staging to work. I will be trying to use the lowest power motors that are safe to keep the altitude low.

2.I will use an altimeter in the booster to deploy a main Chute at apogee. The motor ejection charge can serve as a backup in the booster. Some people are firing the small seperation charge from the sustainer as well as the sustainer ignition. What do you think?

3.Are you running your two ematches into the one ejection charge on a single altimeter output or two altimeter outputs?

4.When you you talk about a tight fit on the rockets joints like the interstage, you mention a shake test, what are you using to tighten up the connection if it is a little loose? Simple tape?

5.Too bad that there isn't more usable AV Bay space in the 3" rockets. It's hard to fit two redundant altimeters in a 3" Bay. I am planning on using Vern's new staging altimeter that links to his Kate unit for the sustainer operations.

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I will try and answer as orderly as possible..... first this is just how I do it, there are many ways to achieve a goal that are different, but correct. I happen to think some of mine are simple and save many steps.

Charlie Ogino is the other half of this project & really is the one "making things happen". We discuss various ideas, work them out. He then draws them up in CAD & machines the parts.. I could not do this without him.

1. Be SURE to kick this thing off the pad hard! For 3 inches I like 4 grain 54's such as CTI K-2045 V-max [500lbs thrust]or White Thunder version for calmer days only 260lbs of thrust.
At versions I love are K-1100- K1103-X and new K-2050 all of these are in 400-450lb thrust range. Your finished stack will be in the 16-17lb to 22-24lb range depending on size motors used. I want at LEAST 10-1 on calm days & [17-20] -1 on windy. If approaching 17-20mph forget about flying, unless you hammer it.

4 grain in booster with a med. 38 to 1-2 grain 54 in booster will only get you around 5-7 thousand. But will kick it hard, for new test flights.

2. For safety reason foremost....sustainer ignition MUST be controlled from sustainer. You can fire separation from it also but that requires fidgeting with running a second wire or controlling both events from same wire. {if I'm following you} The other Jim uses copper tape for his electronics run on side of motor and if memory serves both separation & ignition are controlled from above.

I do my separation from below, electronics in I/S at motor burn out. Some will mention in certain situations you are better off keeping booster connected to sustainer for part of coast.
I do not think with this rocket, anything is gained do so.
I want to lose the dead weight as soon as possible.
I no longer use conduit or light sustainers from inserting igniter into nozzle. I use custom forward closures that hold igniter from above. Eliminating one more issue. [for me that is, I think it's much simpler to do]
One more thing....remember the I/S is ALSO the nose cone for booster.
Make sure to shear pin it well onto fincan. You don't want some weird event pulling it off with sustainer . That can get ugly fast, yes i have seen it.
I actually wipe WD-40 on exterior of my I/S to slick it up. Big difference on ease of separation. I don''t think I ever mentioned that before, usually overlooked. There are so-so many details you will learn on your 2-stage journey. Every one gets better than the last.
Keep this one simple.:smile:

3. one altimeter-two matches in one charge. Somewhere I read thats increases chance of success from like 15,000-1 [which supposedly is the failure rate of e-matces] up to 500,000 -1 this was some statistician doing reliability studies, on anything & everything. I'm won't argue this it's how I do it. Remember motor back up. Biggest failure in everything is user error.

With Big M's I do use 2 altimeters or 1 altimeter and the 2nd channel on timer for back-up

4. I used to fiddle with fiberglass I/S sometimes coating with thin epoxy and sanding to fit. If masking tape is needed your fit it is too far off. At most, thin packing tape or Teflon tape is used to "get, the fit" like here:
https://www.rocketryforum.com/showt...-Head-quot-75mm-to-54mm&p=1477124#post1477124

I now have the luxury of having custom aluminum I/S's made and turned to perfect fit. At burnout we get dart like instant separation with no wiggle in the stack. Now experimenting with real sounding rocket techniques. No I/S based on coupler but rather a cone that inserts into nozzle of sustainer. It's a 2 point based system where tip fits into nozzle that must be extended [exit cone] and base of cone which is flat band. See here for more detail...my&Charlie's sounding rocket build thread:
https://www.rocketryforum.com/showt...2-stage-sounding-rocket&p=1693928#post1693928
Take your time, read the next several posts and blow the pics up, to really see what's going on here. You might even want to go to beginning of thread, there are some really different ways We are doing here, like spin stabilization, & this type of I/S.

By the way it will be flying at Airfest on a M to L combo. This is the 1/2 scale version, 75 minimum booster to 54 minimum sustainer. We are in year 2 of a 3 year P-N project. These are proof of concept flights.


5. You must now think outside the box, 3in av-bays are caverns...lol...
Here's one, same size as yours, containing the following on stack sided sled [layers is the trick]

1 Telemega
1 Missleworks RRC3
1 Missleworks Rtx [GPS]
1 Stratologger
3 lipo batteries
3 combat robotic switches
2external antennas.



Batteries taped to own sled, stacked on top of RRC3, directly under batteries & Strato peeking out of upper right corner. Just enough to expose charge terminal screws.
3 switches are tiny white square delrin blocks on BP. 1 for Strato-1 for Telemage- 1 for both Missleworks units. These can be wired such that if any one fails the other 2 will supply power.



Side view to show placement of above.



Chute-harness-Kevlar protector all fit in between antennas.



Other side of sled with both GPS's Telemega [double as staging] Missleworks Rtx.


Just trying to show with several years of building bays and hours of study in this one, can get a ton of stuff inside what you may think is a tiny bay. I think it's huge. 10 years ago my first 2 stage bay was wood, thick and stuff was zip tied. It would be embarrassing to show pic of that one.
Another thing, dump 1/4in hardware. This is #10 threaded rod hardware, we use #8 & 6# on smaller rockets. Every bit of space counts in these things.

Bobfly said:

On another safety topic. I have not seen anyone launch a two stage rocket at any of the club launches that I have attended. We all install the igniters on the pad for safety with the single stage rockets. Where are you two stage rocketeers installing the igniter on your sustainer? Do you ask the RSO for a designated area away from the flight line, cars, and launch pads?

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This requires a long explanation for detail, but for now short version. Basically at the pads. Internal wire is run at your camp, but stick and igniter carried to pad outside rocket & installed on rail.

For us.....Igniter must be loaded when building motor because we are using HED [head end ignition] closure. The wires are then twisted together to short the matches for safety. More and more fliers are using this, judging by how many dozens of closures Charlie had made in last 6 months.



I have a special test rig, very simple to make. Just a plug/connector that's used to connect the actual igniter to the altimeter.
Staging wire for altimeter is run to terminal block outside bay on BP. Then a short wire with the connector. This connector is is first hooked up to just an e-match. You do all this no matter how you ignite the motor. From top or bottom.

So I hook up the e-match only rig, to the connector on BPlate. This is done at my table before going to pads. Everything gets powered up & checked & re-checked for continuity.
Power down. Hook up connector wire to Front closure. HED. DO NOT YET CONNECT TO ELECTRONICS.

Go to away cell load booster. Load & align sustainer fincan. Now unshort igniter wires from motor and connect to electronics, install into fincan.

After EVERYONE is gone from pad area, everyone. Arm electronics listen for continuity, install booster igniter & retreat to viewing area for flight.
This procedure actually saved on of our butt, when we hooked up just an e-match [by the way, the first time this safety procedure was used] He was standing on 8ft ladder and when we powered up, that instant, no delay, the match popped! Had we done it like so many times before...he would have been cooked. Now we do this back at the table so if something is wrong...it gets fixed before placing on a rail. By the way, that altimeter had been used 2wice before with no issues. Now the FET's decided to leak just enough juice that it would show continuity, but fire a match.

With your project you will need a stick/dowel [1/8in for me...shish-ka-bob skewers for short motors are cheap at the grocery store] Tape igniter for sustainer to this to keep igniter from slipping down, due to booster acceleration. If using CTI motors in sustainer most have the BP pellet in top grain and just an low current e-match is needed to lite motor.

If using AT motors for sustainer or LokI/others and standard igniters....you will need to provide a pyro battery of 11.7 volts or more and be sure pyro latch time is at least 1second or more. Many altimeter default firing time is only .05-.5 seconds not nearly enough time to fire standard 12 volt igniters.
The best method is using low current dipped e-matches or some type of fortified pyrogen such as Pyrodex pellet attached to e-match. I made BP pellets from Estes C-motors and press into top grain or attach to the match ala CTI. Now we make our own BKNO3 pellets.

So going out to pads your igniter on a stick will be taped to side of sustainer, obviously outside the motor. You wire will be run up conduit inside airframe but not yet connected to electronics.

Others are using switched shunts and wireless switches. I have no knowledge of these, so other must explain that use. Above posts do cover lots of that.
These are my methods that have stood the test of time and safety so far.....!
There are many, many ways to do this. What ever you choose, be sure to really understand and do so safely.

Main thing is doing an all up test with only a match, so nothing bad can happen.

Jim- thanks for the posts here. Quick question from my side. I'm building my 2 stage (wildman vindicator jr), and have the ignition wire coming from the upper stage av bay, down through some brake line, to the sustainer motor. What do you recommend to sever that wire so that the drogue charge works properly on the sustainer? I don't want it to just pull the wires out of the terminal blocks- that seems like it's an error waiting to happen.

djs said:

Jim- thanks for the posts here. Quick question from my side. I'm building my 2 stage (wildman vindicator jr), and have the ignition wire coming from the upper stage av bay, down through some brake line, to the sustainer motor. What do you recommend to sever that wire so that the drogue charge works properly on the sustainer? I don't want it to just pull the wires out of the terminal blocks- that seems like it's an error waiting to happen.

Click to expand...

Here's a link to how I do it. Pretty simple.

https://www.rocketryforum.com/showthread.php?18469-Quantum-Leap&p=167160&highlight=break#post167160

Jim

JimJarvis50 said:

Here's a link to how I do it. Pretty simple.

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Thanks Jim! I'll be using a terminal block on the av bay side, so that it doesn't yank on the altimeters, etc. even if it does "hold together"

blackjack2564 said:

Main thing is doing an all up test with only a match, so nothing bad can happen.

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Lots of good information from Jim #2, and he raises the issue of an all-up test. This is something I haven't mentioned on this thread, but that I think is very important. Basically, I do an all-up test at the pad just before loading the rocket on the rail. The test is done by turning on all of the electronics, with the rocket vertical as it will be on the rail, but the ignitor not in the motor. Assuming the ignitor doesn't light during the test, I turn off the electronics (but not the trackers), load the rocket and then fly. This all-up procedure is the last line of defense for not getting toasted if there is an electronics problem of some sort. Related to this....

I have actually designed fins and support stands to allow the all-up test to be conducted conveniently. Point is, consider now how you might actually do the all-up test when the time comes. Years ago, I did this test with the rocket sitting in a guys lap because we couldn't set the rocket on the ground. Not optimum.

The difficulty of doing an all-up test with head-end ignition is why I don't use it (you can't remove the ignitor). If I did use it, I would try to incorporate the idea of the all-up test to the extent possible. I don't think doing this with the motor and rocket not assembled is sufficient. I'm not exactly following what Jim #2 is saying about his procedure, but I think it deserves some thought during the design of the rocket rather than trying to figure out a method after the rocket is built.

Jim

PS - Jim #2 may believe he's Jim #1. Don't buy it - he's crazy.

patelldp said:

Scratch build. The difficulty is NOT in the rocket construction, it's in the configuration of the electronics with proper safeties in place to ensure a safe flight profile.

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Really How many 2 stage high power rockets have you built and how many successful 2 stage high power flights have you flown ?
2 stage rockets are difficult because they are inherently complex . It starts with a good design of the rocket and quality parts and ends with good motor choices.
As far as electronics go I have flown a 2 stage successfully with an old Transolve single event timer using break wires to arm it

Hi Crazy Jim,

Thanks for your detailed answers to my questions. It is extremely beneficial to the rocketry community that senior members with so much experience share their knowledge with us mere mortals. That goes for Jim 1 too and many others.

Crazy Jim, could you please clarify a few things?

For a standard sustainer with rear nozzle ignition you are suggesting temporarily connecting the actual igniter with a test wire to the altimeter outside of the sustainer, No Motor, for a table test. You then arm the altimeter on the table to check for continuity and to make sure that nothing is wrong that will set off the igniter. Turn off the altimeter. Disconnect the igniter from the test wire and twist the igniter leads together to short them out.

Question - For the simple Wildman design, Tim has us installing a 3/8" tube from the sustainer's body through the motor mount centering rings to the nozzle area. Tim's instructions have us run the igniter wire or a feeder wire up to the AV Bay bulkhead. Are you then connecting this feeder wire to the AV Bay on the ground in front of the pad? Or are you connecting the feeder wire to the AV Bay at your table so that you can install and screw the AV Bay / Payload section to the sustainer section?

That would mean that you need a lot of extra igniter wire hanging out of the nozzle area. You need to be able to snake the igniter into the motor with the dowel attached.

I understand that the dowel will prevent the igniter from sliding out of position in the motor. What is preventing the dowel from sliding out of position?

Is this the correct procedure at the pad? Place the booster on the rail, no igniter, place the sustainer with the igniter installed on the rail on top of the interstage. Arm the nosecone tracker, power on the sustainer altimeter or altimeters, listen for ejection charge continuity.

Then in what is the order to install the booster igniter, arm the booster altimeter, and arm the sustainer igniter?

All the best,
Bob

Well Wildman...have you had a recent surge in 2-stager? Good discussion like this hopefully has stirred up some desire. Maybe time for some type of motor combo special for Airfest or MWP! Twice the motors sold for every flight........:wink:

djs said:

What do you recommend to sever that wire so that the drogue charge works properly on the sustainer? I don't want it to just pull the wires out of the terminal blocks- that seems like it's an error waiting to happen.

Click to expand...

My process is different than ''the other Jim".

I don't sever, I slip fit the wire. Holds in place solidly, but a good tug and it comes right out. There is no chance of disconnect during flight.


This is a Molex connector. Either male or female will work. First a 6inch tail is connected to terminal block.




Match wire stripped bare and slipped into Molex connector with just about 1/4 in tail hanging out end. Tails are spread a bit, so there is no way wire can come out till pulled. There are metal clips inside connector that "grab" wire also , this ensures good electrical contact.
The pic has some debris on table, that looks like part of connection. right side of connector pic is just scrap wire on table. Not part of clip as it looks.
Re-usable and sure fire for me. I have also modified JST connectors so they "slip fit" also. solder one half on e-match wire & other permanent one goes to terminal block.
ONE ON MATCH IS SHORTED BY A CONNECTOR THAT HAS BOTH SIDES SOLDERED TOGETHER FOR A DEAD SHORT. It gets removed just before hooking up to electronics at pad

JimJarvis50 said:

The difficulty of doing an all-up test with head-end ignition is why I don't use it (you can't remove the ignitor). If I did use it, I would try to incorporate the idea of the all-up test to the extent possible. I don't think doing this with the motor and rocket not assembled is sufficient. I'm not exactly following what Jim #2 is saying about his procedure, but I think it deserves some thought during the design of the rocket rather than trying to figure out a method after the rocket is built.

Jim

PS - Jim #2 may believe he's Jim #1. Don't buy it - he's crazy.

Click to expand...

Good thing Jim Amos isn't in this discussion then it would be a case of "who's on first?" Lol

To be clear: My all up test uses just an e-match & is no different whether H.E.D or "up the butt" igniter is used.
As you can can see above I have a "plug"in play connector. My all up test uses a connector with match. At my table, the rocket is held in vertical position, that's a good point I also forgot, but due to altimeter ..it must be vertical to function.
So the test match plugged in, all power ups and continuity check.
Power down.
Test match /plug removed.

Put on pad where actual igniter hooked up to electronics. The same safety check used whether it's head end or nozzle insertion. So I really don't see the difference. Hope I cleared that up.

Ok my above post is directed to earlier questions. I just read the last ones & will answer in a bit when I have some time...............

Bobfly said:

Crazy Jim, could you please clarify a few things?

For a standard sustainer with rear nozzle ignition you are suggesting temporarily connecting the actual igniter with a test wire to the altimeter outside of the sustainer, No Motor, for a table test. You then arm the altimeter on the table to check for continuity and to make sure that nothing is wrong that will set off the igniter. Turn off the altimeter. Disconnect the igniter from the test wire and twist the igniter leads together to short them out.

No. Actual igniter will be on stick taped to airframe. Use an e-match only for testing totally separate from real one.


Question - For the simple Wildman design, Tim has us installing a 3/8" tube from the sustainer's body through the motor mount centering rings to the nozzle area. Tim's instructions have us run the igniter wire or a feeder wire up to the AV Bay bulkhead. Are you then connecting this feeder wire to the AV Bay on the ground in front of the pad? Or are you connecting the feeder wire to the AV Bay at your table so that you can install and screw the AV Bay / Payload section to the sustainer section?

Should be 3/16th's foreign brake line, not 3/8. It should stop right where Aero-pac starts.Ya lost me with the rest of it.


That would mean that you need a lot of extra igniter wire hanging out of the nozzle area. You need to be able to snake the igniter into the motor with the dowel attached.

Not really, you pull up slack from top of fincan

I understand that the dowel will prevent the igniter from sliding out of position in the motor. What is preventing the dowel from sliding out of position?

The nozzle cap or bottom of I/S ..where is it going? You can tape it to nozzle if you wish.

Is this the correct procedure at the pad? Place the booster on the rail, no igniter, place the sustainer with the igniter installed on the rail on top of the interstage. Arm the nosecone tracker, power on the sustainer altimeter or altimeters, listen for ejection charge continuity.

Then in what is the order to install the booster igniter, arm the booster altimeter, and arm the sustainer igniter?

Man I'm getting dizzy with all this...LOL You need to slow down, start building and ease into all this.
I can't find my build instructions thread for this kit, it's in here somewhere, with detailed pics of most everything. Maybe someone else can find that thread & post a link. Would sure simply all this for you. My problem is that was 7yrs ago and I build dramatically different now. I'll try and find some of the pics from instructions. Did Tim supply instructions somewhere? Know all this is in there.

All the best,
Bob

Click to expand...

Hope this helps a bit.

Thanks Crazy Jim for taking the time to try and answer all of my questions. Tim doesn't provide any paperwork with the kit at all. There isn't even a material list. Tim does have some instructions that are very helpful for some of his kits online. They seem to have all been written back in 2009. Many of the kits have no instructions at all. Tim informs me that he is in the process of updating his website. The updated website will have general instructions that can be applied to all of his kits.

This Forum is extremely helpful. Many Modelers share technical information which is simply not provided by the kit manafactures. Public Missiles, and Apogee Components have some limited information about altimeter installations. I haven't found any two stage kit manafactures with avionics installation suggestions with the exception of Public Missiles. The Public Missiles information is pretty much just suitable to their own products.

The "Rocketry Club" system is great for the general sport. Clubs provide knowledgeable Mentors to easy new people into the sport. I have learned a lot from Club members. Many of the vendors are knowledgeable too. Often the vendors are willing to share their knowledge too.

Unfortunately there doesn't seem to be a lot of local club members flying two stage kits. Therefore I don't have access to the breadth of knowledge that is available locally for the single stage rockets.

Two stage rockets are inherently more dangerous than single stage rockets. That is why I started this thread. The set of "Jim's" have been more than helpful in sharing their knowledge base. Others have been more than kind in responding to this thread.

I cannot believe that over 3,500 people have viewed this thread in just over two weeks. There must be serious interest in two stage high power rockets. Tim and other manufacturers should take notice. They might sell more product if they provided more information on the two stage kits on their websites. This additional information should contain suggestions for avionics setups. The airframe manufacturers should work with the avionics manafactures on forming alliances.

All the best,
Bob

Bob- if you tell us where you're located, you might find some people on this thread that are local to you and have built two stagers before.

Hi djs,

I live in Garden City, NY on Long Island. I am a member of the METRA Rocket Club that flys out of Pine Island, NY. I am also a member of the URRG Rocketry Club that flys out of Potter, NY. Unfortunately Potter is quite a drive for me. Potter is in Western Upstate New York. Therefore I can only attend two weekends a year at Potter.

All the best,
Bob