Help on selecting a first two stage high power rocket kit

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Hi Jim,

Thank you for your thoughtful detailed response. I was using 22 Gauge multi strand wire for the switches. I’m going to follow your original recommendation and drill a fourth hole just for the switching.

I have to call Apogee to ask them help me sort out a Rocksim issue. My Rocksim program has been working great for all of my single stage rockets. I am having issues with the software when trying to run two stage simulations. This will have to be worked out before the first flight.

Tim’s Wildman 3” two stage is a different version than mine. Tim’s Rocket is lighter than mine. It now looks like the Loki J 820 that Tim used in his booster may be a little under powered for my two stage flight. That motor would provide about a 10 to 1 ratio. I have a Loki Motor that will put out 350 pounds of thrust. It also has over double the newtons of the J 820. That’s not necessary for a first test flight.

I will check out the motors that you have listed. At this point I have a wide assortment of CTI and Loki cases. I am hoping to be able to use one of these brands so that I don’t have to buy cases for a third product line. To keep things simple, for the initial flights anyway, I am going to use a CTI Motor in the sustainer.

Jim, were you The rocketeer that was using Loki Sustainer Motors with Scott’s forward end ignition system?

Thanks for the advice,
Bob
 
Jim, were you The rocketeer that was using Loki Sustainer Motors with Scott’s forward end ignition system?

Thanks for the advice,
Bob

No... but I do use head end ignition closure's of our own design, for both AT & CTI. All aluminum & re-usable. I have them in every size 29-98mm . Simply remove plastic closure..remove O-rings..place them on Aluminum H.E.I. closure and put on motor. [CTI] For AT just use O-rings in re-load.
Loki makes nice motors, I just have so much other hardware, never got around to trying them.

Typical CTI 54 closure:

DSCN0025.jpg DSCN0028.jpg


Is Scott's single use or re-usable?


This is how I use... 2 matches hooked to terminals [I believe in back-up] no need for 2

One folded.... gets inserted into pellet with hole in it [pressed into top grain] this goes through hole and fires back up to pellet. Just as a normal match inserted through nozzle and placed to top grain would.

2nd back up stays on top of pellet, so it lights from both sides.

DSCN0119.jpg

We are now designing/testing pellets cast onto raw match wire. No pyrogen needed with 40ga. low current nichrome [same as used in E-match] & BKNO3 resin cast.:dark:
 
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CJ--
After several "learning" flights, my preferred minimum size motors are 3-4grain 54mm's producing 350-500lbs thrust or more. [booster] AT...J-1520 K-1100 K-1103X-K805......CTI K-2045 K-940 J-760 I prefer 15-20 to 1 when possible.

Teddy you'll have to add comparable Loki's to this list.

Jim,,
IMHO the reason for your consistent success is your patience...
I am a believer in starting any rocket with easy loads and working my way up to really pushing the rocket...
For me,, what your calling learning flights is absolutely key...
Loki is known for punch and particularly punch just after ignition right off the pad...
For that reason the Loki high thrust loads in every case size are perfect for a booster in a multi stage flight..
38 / 480 -- I 430 LB or I 405 LW
38 / 740 -- J 712 LB
38 / 1200 -- J 1000 LW , J 1026 CT , or the K 1127 LB
54 / 1200 -- J 820 LW Star grain
54 / 2000 -- K 960 LW
54 / 2800 -- L 1400 LW, or the L 1040 LR

I use pyrodex pellets in every motor I light..
It's just too easy,, and your right,, why burn Ns chuffing on the pad...

When your in a situation that you need punch- now--
try one of these loads,, but beware,, just like my harnesses,, it's a dark path-- there's no going back,, lol..

Teddy
 
This is how I use... 2 matches hooked to terminals [I believe in back-up] no need for 2
One folded.... gets inserted into pellet with hole in it [pressed into top grain] this goes through hole and fires back up to pellet. Just as a normal match inserted through nozzle and placed to top grain would.
2nd back up stays on top of pellet, so it lights from both sides.
View attachment 332119

This looks like a good setup, I could see replacing a a Loki Bulkhead with a new machined one similar to this. However, I assume that falls under motor modification and would not be allowed under the NAR safety code?

cheers - mark
 
This looks like a good setup, I could see replacing a a Loki Bulkhead with a new machined one similar to this. However, I assume that falls under motor modification and would not be allowed under the NAR safety code?

cheers - mark
HEI = EX
 
Hi Jim,

You would have to talk to Scott at Loki about his head end ignition system. I see instructions for the product on the Loki website, www.Lokiresearch.com, on the documents page. It seems that Loki was making a smoke grain with short wires molded into the grain.

The instructions inform you how to install a igniter onto the smoke grain. The standard Loki forward closure was being used. Loki just tells you to remove the top screw from the forward closure. This would be a very simple system. The forward closure would therefore be reusable.

While the website has instructions for the head end ignition system, I could not find the wired smoke grain listed on the purchase order page. We would need to speak to Scott to find out if it is still available. Some of Scott’s products are labeled as experimental. Scott would have to tell us if his product is still available, and if it is experimental.

I was able to fit two break line tubes into my 3” sustainer. This will allow me to run wires from the sustainers AV Bay down to the sustainers motor area. One break line for a seperation charge. The other break line being for the ignition wire. I really like your head end ignition system.

Jim, as a general principle, do you think it is safer to use a low power 10 to 1 ratio motor, or your recommended way higher initial thrust motor? I am 100% confident in the Wildman kit and my construction.

All the best,
Bob
 
Bob,,
I have a 54mm forward bulkhead already done and set up with the grain in it
and the ignition wires coming out of the forward side of the bulkhead...

Just as a point of information,,
When you first start staging the more thrust off the pad the better..
And the shorter time to igniting the sustainer stage the better..

Have you seen Fred T's staged flights Bob ??
He's a nice man and the most experienced in staging around..
He just put up a successful 4 stage flight at MWP..
He likes to use Warp 9 propellent off the pad to lift the stack...

Teddy
 
Hi Teddy,

It’s great that you have a 54 mm forward closure with a wired grain in stock. Is Loki still making these? I didn’t see it for sale on the Company website. Am I correct in assuming that the forward enclosure is reusable? Only the smoke grain with the wires needs to be replaced for each flight?

Are the wired smoke grains still being made? The forward head ignition seems great for future flights.

Thanks for the info,
Bob
 
He likes to use Warp 9 propellent off the pad to lift the stack...

That propellant had an ultra fast burn rate with a near instantaneous maximum thrust curve about three times the thrust over other motors in its letter class. It needs a plugged motor forward closure with a separate electronic deployment. And under high accelerations the batteries can disconnect.

Simmed an L-1 multistage past 20,000ft at over 168G acceleration. First flight test structurally demolished it on I1299N by 2,500ft as supersonic in under half second, interstage coupler failure. Model was 2lbs... The electronics absolutely hated that g loading. And the velocity of rail was so high that it tracked wonderfully in winds.

On a heavy model it's likely a good motor. Or just be real careful about the interstage design and construction because it's getting like a 340 lb force load in under a third of second from the I class. One RSO was yapping you kids put a sledgehammer motor in there. They all laughed and told us we needed more burn time not Thrust for high alt. It's a solid reload no complaints on its performance.

In theory this 1299N is spent in a third of a second and the second stage could ignite a second after it supposedly... If you needed to shed altitude in a good way by decreasing the stage timing intervals and logic triggers. If you start increasing the stage sustainer ignition timing you'll see a ridiculous increase in alt from the momentum transfer.
 
Hi Teddy,

It’s great that you have a 54 mm forward closure with a wired grain in stock. Is Loki still making these? I didn’t see it for sale on the Company website. Am I correct in assuming that the forward enclosure is reusable? Only the smoke grain with the wires needs to be replaced for each flight?

Are the wired smoke grains still being made? The forward head ignition seems great for future flights.

Thanks for the info,
Bob

Bob,,
I'm not sure what Scott from Loki is going to do with these head end ignition forward enclosures..
The fact that I have one in 54mm is a strange circumstance..
To answer your questions,,
First, yes, it is absolutely reusable, as any forward, just replace the smoke grain,
but you'd have to get that grain separately from any load you bought..
I will venture a guess that if you were interested in this Scott would make you a few grains..


That propellant had an ultra fast burn rate with a near instantaneous maximum thrust curve about three times the thrust over other motors in its letter class. It needs a plugged motor forward closure with a separate electronic deployment. And under high accelerations the batteries can disconnect.

Simmed an L-1 multistage past 20,000ft at over 168G acceleration. First flight test structurally demolished it on I1299N by 2,500ft as supersonic in under half second, interstage coupler failure. Model was 2lbs... The electronics absolutely hated that g loading. And the velocity of rail was so high that it tracked wonderfully in winds.

On a heavy model it's likely a good motor. Or just be real careful about the interstage design and construction because it's getting like a 340 lb force load in under a third of second from the I class. One RSO was yapping you kids put a sledgehammer motor in there. They all laughed and told us we needed more burn time not Thrust for high alt. It's a solid reload no complaints on its performance.

In theory this 1299N is spent in a third of a second and the second stage could ignite a second after it supposedly... If you needed to shed altitude in a good way by decreasing the stage timing intervals and logic triggers. If you start increasing the stage sustainer ignition timing you'll see a ridiculous increase in alt from the momentum transfer.

Andrew,,
Just a point,, if you read your post you seem to be focused more on the thrust of the Warp 9 propellent then the weight of the rocket on the pad..
There is no difference.. One has the same effect as the other.. I have seen many of Fred's flights,, he get's a fantastic wow factor in them by staging the first time down low,, I think as low as a couple of hundred feet.. So he has more weight on the warp 9 load then a few pounds.. Again though,, you'd be better off hearing numbers from Fred himself..

Teddy
 
Dumb question about staging: when you ignite from the rear, what happens to the spent igniter/nozzle cap? From the setups in this thread, it looks like it’s hihly likely to get hung up in the conduit, or stay attached to whatever terminals you have at the tail -am I missing something obvious? Wouldn’t want a length of wire dangling behind the sustainer during boost, I wouldn’t think.
 
Hi Jim,

Jim, as a general principle, do you think it is safer to use a low power 10 to 1 ratio motor, or your recommended way higher initial thrust motor? I am 100% confident in the Wildman kit and my construction.

All the best,
Bob

As long as wind conditions permit. You should use some type of wind site to check the uppers. It can be dead calm on ground & as low as 300ft blowing 15mph.
I use this: Put in your launch site or zoom out and move pointer and click on your state..etc..till you enlarge to see yours. Setting under "advance" allows for satellite view and bottom slider will give forecast for various time of day for 7 day forecast.

https://www.windy.com/?800h,34.106,-80.547,16,m:eBZadUT,a:zLFFF

Here is our site few minutes ago 7 on ground: click on these several times to blow up full scale & see the data.

Screen Shot 2017-11-17 at 1.53.22 AM.jpg

15 at only 2000ft

Screen Shot 2017-11-17 at 1.52.35 AM.jpg

And 22 at 10,000 Also note the extreme difference of direction between the 3.

Screen Shot 2017-11-17 at 2.00.52 AM.jpg

So where you may think 10-1 is enough as the ground shows above...when passing through 2,000 you get hit with a wind shear of 15 that may cause some bad weather cocking and a non vertical flight....same higher etc etc.

On near dead calm days...no clouds moving, you can get away with low thrust stack. I was apprehensive [scared] when attempting first flights. In doing so selected some borderline motors, "playing it safe" when in fact it had opposite effect and was rewarded with some screwball, non vertical flights I would not want to do again.

Now it's go time, every time, lessoned learned. Everyone has a different tolerance level....you'll find yours.
You keep asking & I keep telling you..I want my booster always smacking the stack in the butt.
Put a small motor or NONE at all in sustainer, if wanting to keep things low at first. I have several test flights , where motors were fully loaded, but no igniter in sustainer to check functionality of my programing . [E-match on staging pyro bulk plate, to see if it fired] Deployment on sustainer functions etc. Does it need separation charge or not, among other results I graph and study after flight.
So it is ALWAYS safer to use highest thrust booster motor rather than lower. :smile:


Dumb question about staging: when you ignite from the rear, what happens to the spent igniter/nozzle cap?

When I used to use conduits, I have igniter on stick, held in place by nozzle cap. Tape wire to outside of cap. Every time motor fired it would forcefully push cap off...pulling excess match/igniter wire with it. To do this requires careful packing of cordage/drogue. Lay airframe horizontal while packing, allows wire to lay on bottom of tube. As you slide gear/nomex into tube, pull wire snug and hold in place while sliding gear over it. Now has a clean path to pull clear.
When hooking up ignition wire to av-bay, use a slip fit connection that can pull free easily. I use connector where bare wire slips into a female side of plug.

Screen Shot 2017-11-17 at 2.40.20 AM.jpg

Whole shebang goes out back end when motor fires, leaving nothing in fincan to tangle with gear when apogee fires. That's my solution when using conduit, found by many flights and trial/error.

"Playing with 2 stagers is not twice as hard...it's 10x more intense." Cj
 
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While staging, is there a suggestion for a safe minimum velocity to maintain? I'm concerned about minimizing the amount it arcs over using staging electronics without a gyro. One of our two stage rockets has an easymega, the others are going to have to live with Eggtimer Quantums for now.. Our (ambitious) plan is flying at least one two stage at every local launch this year to be better prepared for two stages at Airfest.
 
That "sweetspot" in velocity can change for same rocket..flight to flight, depending on many things.

Size -weight-stability-drag of design. Some rockets will retain speed better and that dreaded "gravity" turn will come later...rather than sooner.

Thrust profiles of motors choosen for flights will also have a major effect on velocity choice [for me anyhow]

Finally the easiest to adjust & major player in this game: staging delay or coast.

Example: 3in rocket .weighing 15 lbs [both stage] Load up a 2 grain 54 in booster & 3-5grain 38 in Sustainer.

No /little wind 2-3mph . Feel OK with 8-10 to 1 thrust ratio and 400ft/sec velocity or greater. Stage at 350f/p/s.

Change the wind [over 10mph] or weight [different size rocket] now I want. 15-20 to 1 thrust ratio. 6-700f/p/s or more velocity. Stage at no less than 475-550ish velocity.

With higher thrust motors you can dial down staging velocity [sustainer ignition]by longer coast times.
Marginal thrust motors need to have little [1 sec] or no delay to keep velocity safe from arcing.

Need for flight profile plotting added to your sims, is a basic requirement for smart motor choices these days.

Of course one can just use recommended motors the have flown successfully. Unfortunately you won't have the basic understanding of how to pick or combine motors on your own, unless you develop these skills.

So the reason behind the madness above.

Short answer [for me] is light small rockets ...say Jr size I want 350-500vel. stage at no less than 300.
Larger heavier 600 or more [the better] off the pad/during flight. Stage at around 500 no less.

My ideal flight profile 3in rocket 16-26lbs: Hammer it off the pad with 350 to 800lbs of thrust and stage at no less than 650ft/sec you will get dead nutz flights, time after time
 
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Short answer [for me] is light small rockets ...say Jr size I want 350-500vel. stage at no less than 300.
Larger heavier 600 or more [the better] off the pad/during flight. Stage at around 500 no less.

My ideal flight profile 3in rocket 16-26lbs: Hammer it off the pad with 350 to 800lbs of thrust and stage at no less than 650ft/sec you will get dead nutz flights, time after time

This is gold! Thanks for the detailed advice.
 
Hi Guys,

I was waiting for Vern Knowles new staging altimeter. Unfortunately it looks like that device isn’t going to come to market any time soon. I’m going on vacation next week. When I get back I’ll be asking you experts for some advise on an alternate staging altimeter.

The rocket is fully completed and painted. Stickershock jazzed the rocket up with their great decals.

All the best,
Bob
 
Hi Everyone,

I have been getting a bunch of private messages asking if I ever launched my Wildman 3” two stage rocket. Therefore I thought that it was time to update this thread. I will be launching this rocket for the first time at URRG’s June 22-23-24 URRF 5 2018 event in Potter New York.

The rocket had been completed and painted last fall. All that remained was to build the sustainer stage AV Bay. I had been waiting for Vern Knowles to complete the testing of his sweetheart staging altimeter. This staging altimeter was going to be linked to Vern’s Multitronix Telemetry Pro “Kate” System. Unfortunately Vern is not going to bring this altimeter to the market in the near future. Therefore I had to come up with an alternate sustainer staging altimeter solution.

The booster’s AV Bay interstage had been completed last fall. The below photo shows how I was able to shoehorn a Missle Works RTX GPS Tracker and two Missile Works RRC2+ altimeters into Wildman’s 54mm interstage AV Bay. There was no room for anymore electronics to fire a staging seperation charge. Since Vern’s altimeter would have triggered a staging seperation charge, I had installed two brake line conduits into the sustainer stage during construction.

Now it was necessary to be able to trigger off a staging seperation charge and the second stage ignition from the sustainer’s AV Bay. This wouldn’t have been a problem except for the fact that I like redundancy for my parachutes. The below photograph shows my finial solution. I was able to install a Missle Works PET2+ Timer with a Missile Works RRC3 Altimeter, and a Missle Works RRC2+ Altimeter.

The PET2+ Timer will have only one job. The PET2+ will just be responsible for firing off the staging seperation charge. The RRC3’s third channel will be used to ignite the second stage motor. The RRC3 will also handle both of the primary charges for the drouge and main parachutes. The Missile Works RRC2+ will handle both of the backup redundancy charges for the drouge and main parachutes.

It was tough figuring out how to fit in three separate batteries to operate all of the electronics. Fortunately I was able to find the Turnigy nano-tech 300 mAh 7.4 Volt LiPo battery. Two of them fit nicely in a MAC Performance printed 9 volt battery box. I installed the MAC Performance 9 Volt battery box onto a cut down MAC Performance printed 3” sled. The top of the sled has the PET2+ and RRC2+ installed on it. The underside of the sled has the battery bos installed on it. The two 7.4 Volt LiPo’s power the PET2+and the RRC2+.

Missle Works sell a 3” printed sled that is specifically made to fit their RRC3 Altimeter. I used this sled to mount the RRC3, a switch, and a alkaline 9 Volt battery.

The only thing that I still have to decide upon is if I am going to use twisted wire or Binder Design Arming Screw Switches for the PET2+ and the RRC2+.

I really have to thank Tim, Timbucktoo, for his help in setting up my RRC3’s third channel. The Missile Works instructions and the Missle Works computer interface need improvement. Tim has successfully flown his Wildman 3” two stage using the RRC3 to ignite the second stage. Tim spent a hour on the phone with me and my Company’s IT Tech. If it wasn’t for Tim’s assistance we wouldn’t have been able to program the RRC3’s third channel. Thanks Tim. This is a great thing about this Forum. I was able to get help and advice from Tim who lives in Florida while I live in New York.

All The Best,
Bob
L3

BDCFEAFB-F052-4611-AA3F-191A665DE3CA.jpg

053BC1D0-D573-48AB-8A45-ED76B7DE6B97.jpg
 
The Raven was as simple as insert <=, =>, or = then altitude, time, or velocity. It wasn't hard at all. I haven't used a RRC3.
 
Someone like yourself probably impossible to do but for the flyer who reads and follows instructions, pretty straight forward.
Note how the RRC3 customer had to call and talk with him for an hour to simply use the product. Obviously the instructions on RRC3 products could be clearer.
 
Hi Guys,

I&#8217;ve been using Missile Works RRC3&#8217;s for a couple of years. I must have about a dozen of them. They are real easy to program Channel 1 and 2 using the Missile Works LCD attachment. I have never had a need for the third channel before working on this two stage project.

The third channel can only be programmed from a computer. You need to use the Missile Works interface circuit board / cable to accomplish this. Our main problem was that we could not get the RRC3 to link to the computer. In the past Jim at Missile Works was very good at getting back to you in a timely manner. Unfortunately Jim wasn&#8217;t available for a prolonged time period. That&#8217;s when Tim was kind enough to help.

It seems like many of the vendors / manafactures involved in our sport are part timers. That makes it hard for them to answer questions and update products in a timely manner.

All the best,
Bob
 
Hi Guy’s,

It’s been awhile since I updated this post. I wasn’t able to test launch my Wildman 3” two stage rocket until this past August weekend up at Potter NY. The boost phase worked out perfectly utilizing a 54 mm Loki J820 as you can see in the attached picture.

Unfortunately, the Missile Works PET2 timer didn’t fire off the staging seperation charge. The RRC 3’s auxiliary’s channel didn’t fire off the sustainer’s ignition motor ematch. Therefore the sustainer motor never fired. I’m going to have to get assistance from my companies IT Technician to go over all of the Flight data from the RRC3 and Kate units to try and figure out what went wrong.

Fortunately the parachutes deployed properly and the rocket was recovered with no damage. The Loki J820 was a good motor choice for test flights. The J820 had enough punch to aggressively push the 28 pound fully loaded stack up to 1,500 feet. At this altitude you could clearly see the stage seperation. You would have been able to see the second stage ignition if it had worked. I had a small one grain CTI motor in the sustainer stage just to test the whole two stage launch ignition process out.

I made one mistake during construction which I want to warn anyone whom is considering building this kit about. I ran full length brake line tubing all the way up from the motor mount to just underneath the sustainer’s AV Bay. I thought that this would prevent the motor ignition and separation charge ematch wires from being tangled or disconnecting by the recovery gear. Big mistake. It was almost impossible to thread the ematch wires down through three feet of narrow break line tubing.

I was able to thread one 24 gauge ematch wire down one of the break line tubes with great difficulty. It was impossible to thread the second 24 gauge wire down the other break line tube. I had great difficulty threading a thinner 26 gauge wire down the second break line tube.

A backyard test revealed that the 26 gauge wire had a hard time supplying enough current from a 9 Volt battery to ignite an AeroTech FirstFire igniter. I therefore switched the second stage motor to a CTI motor which could be ignited with an ematch.

I’ll write up a follow up posting after our investigation as to what went wrong with the staging seperation charge and the second stage ignition process.

All the best,
Bob
 
I'm sorry the second stage didn't light. On the plus side, of all of the staged rocket failures to have, the sustainer failing to light and stages failing to separate are the best ones. I hope you sort it out and get it back on the field.
 
Hey Bob, sorry the sustainer didn't light off. That happened on my first flight too. After reviewing the RRRC3 data I was able to see the error of my ways and tweeked the aux channel enough to get it to light off on all subsequent flights. Once you get the data, please share as I am sure we can help you figure out what happened.
 
And you recovered it undamaged. Look with multistages a lot worse can happen like interstage implosion or ballistic recovery sustainer. Sustainer stages always will be temperamental to light. It’s just the nature of it. This was a best case failure because you tested the fail safe systems and it recovered after the sustainer didn’t do what you wanted.

It took multiple tries for my school team to get the hang of it without a mentor. Don’t feel bad. Even Crazy Jim had to dig one out of the ground at ROSCO this year, ballistic recovery sustainer. And he flies them regularly with high experience.
 
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