Black rock project 2 stage 2018 min diameter

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Do you have a picture of your Missile Works RTX and GPS antenna setup? The GPS receiver and antenna are made on one board that plugs into the RTX board by an 8 pin header from what I can tell from the Missile Works pictures I've seen. It's not clear to me how you can mount the GPS unit remotely from the RTX. I'm only going by what I see on the Missile Works website, but maybe they have other solutions than what's in this picture. The GPS antenna is the square piece at the top. If the GPS antenna is facing towards the fiberglass AB bay lid, I suppose that should work.

Your picture is misleading. You are showing both the RTx & an RRC3. The GPS is part of the RTx board. He is using the RTx standalone in the NC.
 
Yeah, it was not my picture. I linked a photo from Missileworks but deleted it since it didn't seem to be what Andrew is describing, but was the only pic of the RTX and GPS that I saw on the MW website. Sounds like he has it figured out.

I have not yet received my RTX from the cyber monday sale from MW yet. When I do I will post a pic of my setup here.
 
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got 2 holes drilled into airframe next to fins. Holes will be covered by fillet. These are for to inject CR fillets on the inside. Also, holes will serve as a way to inject 2 part foam.
 
How many of you guys are going the drag separation route or actually having a small charge to separate?

On my few two stage flights: j-I, k-j - I've used a charge to separate the interstage coupler and sustainer. 0.3 -0.5 gram 4F.

Works well.

I'd recommend it. You might like to check out the projects of the staging gods though - Jim Jarvis and others have written great stuff on staging etc.

Good luck with your flight.
 
On my few two stage flights: j-I, k-j - I've used a charge to separate the interstage coupler and sustainer. 0.3 -0.5 gram 4F.

Works well.

I'd recommend it. You might like to check out the projects of the staging gods though - Jim Jarvis and others have written great stuff on staging etc.

Good luck with your flight.

What type of electronics do you use to ignite the seperation charge?
 
It's a timer yes but has many options and they're all based on main engine start, cut off or sustainer start, cut off. Your choice but it's perfect for ISC separation and booster recovery.
 
It's a timer yes but has many options and they're all based on main engine start, cut off or sustainer start, cut off. Your choice but it's perfect for ISC separation and booster recovery.

What I would need it to do is.... Seperate the ISC then fire a charge at apogee break apart. Then at a special altitude deploy the main. I am using dual cable cutters. Can it do all those in the same flight?
 
What I would need it to do is.... Seperate the ISC then fire a charge at apogee break apart. Then at a special altitude deploy the main. I am using dual cable cutters. Can it do all those in the same flight?

It only has 2 event timers. I used it to separate ISC based on X seconds after booster burnout and then to fire second charge for booster recovery at the expected time of booster apogee. I also had a jolly logic chute release to deploy the booster main at 400'. It all worked as planned.
 
It only has 2 event timers. I used it to separate ISC based on X seconds after booster burnout and then to fire second charge for booster recovery at the expected time of booster apogee. I also had a jolly logic chute release to deploy the booster main at 400'. It all worked as planned.

thanks
 
I always figured that when I try a two stage, I'd run a basic altimeter for booster recovery, and a timer for separation, and maybe booster apogee backup.
 
Got the internal fillets on the CR's done. Now on to the foaming the fin can with 2 pound foam.
 
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I drilled holes next to fins to inject 2 part expanding foam; 2lb. Then I taped over the holes so that foam will go into every spot in the fin can.

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The foam oozing out of the holes.

I did this because there are no fin tabs. The motor mount has 3 CR's. There is a fillet on each side of the CR's. Then there is expanding foam between motor tube and airframe. The foam not only fills voids it adds strength and rigidity and additional adhesion.
 
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Right now I weighed out everything. Does not include recovery or electronics or outside fillets. The rocket comes in at 9.71 pounds.
 
I have started the fillets. I am using the Hysol E-120HP for the fillets. I am using a 1.5 inch PVC coupler to pull the fillets. Since I am not doing tip to tip I needed some beefy fillets. It takes about 25 grams per fillet on the sustainer. Pics to come.
 
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2:1 ratio blunder from McMaster carr. Adapter for a standard caulking gun.

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50 ml tube of hysol e-120hp

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The whole set up. This is great. The caulking gun adapter was cheap. Way better then buying the loctite dispenser.

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One side of the fillets.

I am using the mixing tip. Using those creates no air bubbles. Yes it wastes some epoxy but I think the benefits out way the wasting.

I am using a 1.5 inch pvc coupler to pull fillets. I am not doing any tip to tip. They are all surface mount fins. There needs to be meaty fillets
 
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Next step is to wet sand the fillets. I have never sanded Hysol e-1250hp. I will start with 220 grit and work my way up. Here goes the battle.
 
I was thinking of using Fly away rail guides on this bird using a 12 foot rail. The flyaway guides on the booster just about fins and then another set on the sustainer right above fins. The other option would be to use fly away guides on the booster and then traditional rail guides on the sustainer(3 inch with a 54mm hole)

What do you think?
 
Been on a building hiatus. Son was born and life happens.

I have decided not to do this 2 stage at Argonia at Airfest 2017. Just gonna fly it as 2 separate rockets. I am making plans to head to Black Rock in 2018. I think flying it at Black rocket is better because I dont have to worry about the waiver. It gives me another year of planing. Anyway to do it right I need to get some more electronics. I am going the Altus Metrum route. They are expensive but for a good reason they are the best. This gives me a good project to head to Black Rock with. When I started making plans to go to Black Rock I did not have a project. Now there is more reason to drive the 1700 miles one way. The additional electronics are another grand. Gives me more time to save.

The Altus Metrum v2.0 is $300 (tracker for booster)
The Easy Mega v1.0 is $300 (primary altitude deploy and lighting 2nd stage)
The TeleBT v3.0 is $150
Arrow 3 element Yagi (dont know how much)
 
build has resumed. I am choosing either between M1297 or M1850 in a single stage configuration in the booster at Airfest 2018. The only big difference is about 8,000 feet in altitude. I will then fly the sustainer in a single configuration later at a different launch.
 
Know anyone with an old GWiz Deluxe 800 you can borrow? That would be the ticket for your booster. Sustainer sep charge at booster burn-out, then an apogee channel and main pre-set for 800 feet. I always found them reliable as hell. And they were $135. Shame they don't make 'em any more.
 
Curious as to why you would want to use sustainer ignition to separate stages. I have seen a sustainer CATO because it was a little too tight into the interstage coupler and the motor subsequently overpressurized in that split second the two sections were stuck together with the motor burning. It was a spectacular CATO. I think the explosion was heard in the next county.
 
Curious as to why you would want to use sustainer ignition to separate stages. I have seen a sustainer CATO because it was a little too tight into the interstage coupler and the motor subsequently overpressurized in that split second the two sections were stuck together with the motor burning. It was a spectacular CATO. I think the explosion was heard in the next county.


What the heck are you talking about?? There will be an aux event inside the booster ebay on the altimeter. After booster motor burn out a small separation charge will go off to separate the stages. Then the sustainer will continue to coast before the sustainer is lit by the aux event in the sustainer ebay. Does that make any sense?? The idea is to protect the booster from the sustainers ignition. Go for maximum altitude.
 
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Curious as to why you would want to use sustainer ignition to separate stages. I have seen a sustainer CATO because it was a little too tight into the interstage coupler and the motor subsequently overpressurized in that split second the two sections were stuck together with the motor burning. It was a spectacular CATO. I think the explosion was heard in the next county.

Yes this can and will happen . Ask Mark Clark . Thunderbolt 1 if I remember correctly . One way to prevent this is to use vent holes in the ISC equall to the throat area of the upperstage motor ( if you are keeping the stages together and not seperating them before ignition ) .

Eric
 
Yes this can and will happen . Ask Mark Clark . Thunderbolt 1 if I remember correctly . One way to prevent this is to use vent holes in the ISC equall to the throat area of the upperstage motor ( if you are keeping the stages together and not seperating them before ignition ) .

Eric

Thunderbolt 2 was the one that blew.

The plan was as the motor pressurized the booster comes off, in single stage flights the motor took 2-3 seconds to light. The booster was only on for about 0.2 seconds after booster burnout.
Putting the unvented inter stage into the mix it essentially was a plugged nozzle and the motor pressurized instantly. Looking at the part of the motor case that was in the inter stage it did not move before the cas failed.
The solution was to vent the inter stage coupler, six 3/4" vent holes were used, equivalent to greater than the area of the nozzle exit (not throat) area. Testing is tough, O and M motors and one test annually. Fortunately I was right and it worked the second try.
I now use separation charges when I do multi stage and would have for this rocket but at the time we only had single event timers and there were already two for redundant motor ignition, no space left in the inter stage. The timers were incinerated by the sustainer motor.
This rocket was recently simmed to over 100k. I have no idea how high it went as there were no high altitude altimeters, the plan was for visual tracking!

M
 
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The whole stack together. I am not flying in this config until black rock 2018. But to get ready for that I am preparing in the way. It will fly in single stage config at Airfest 2017.
 
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