Two Stage Rocket Question.

[Jay515]

Just starting out with model rocketry with my teenage son. We've built and launched a few low power rockets, and we're ready to build our first two stage rocket. Looking at ordering a Loadstar 2, and I have a question about retaining the second stage engine. When the second stage engine's ejection charge fires, what prevents the engine from coming out of the bottom of the rocket body? Also, if there isn't any retention, will there still be enough pressure from the ejection charge to deploy the parachute? This rookie appreciates any advice you can give. Thanks!

 

[neil_w]

I'm not specifically familiar with the Loadstar's construction, but commonly the sustainer motor is retained with friction. You wrap tape around it until you get a nice snug fit. If you do it right it'll eject just fine.

Welcome to the forum!

 

[Jmhepworth]

Masking tape. Estes 2 stagers are really easy. Use cellophane tape to connect the two motors together. The heat from the sustainer motor igniting will separate the two stages. And then use enough masking tape wrapped around each motor so that the fit in each of the motor tubes is very snug. It should not be easy to get it to come out. And then make sure your nosecone comes out a lot easier than the motor. Be sure to use lower impulse motors for the first flight so you get it all back. And then put in the biggest motors that fit and get out your binoculars.

 

[Jay515]

Thanks for the replies! I can't wait to get the kit and try it out. This hobby is incredibly addictive!

 

[Jack Arne]

If I friction fit the second stage with masking tape, clear tape the two engines together, and friction fit the first stage to its individual body.... will this work? I know it’s harder with a minimum diameter tube. @Jmhepworth

 

[BABAR]

Second recommendations for lowest impulse motors, especially the sustainer.

Practice “loose” packing of wadding, chute, and nose cone, you should be able to blow these out easily with a breath.

Friction fit works pretty well. If find that, after a flight, if I remove the motor right after I recovery it, it is easier to get out than if I leave it in until I drive home.

Added tip for all black powder rocket motors, remove the motors and either dispose of them in a garbage can or put them in a ziplock bag, otherwise your car gets that “eau de BP”, which is cool enough at launches, not so much in your car the next day....or week!

 

[Jmhepworth]

If I friction fit the second stage with masking tape, clear tape the two engines together, and friction fit the first stage to its individual body.... will this work? I know it’s harder with a minimum diameter tube. @Jmhepworth

Exactly. Each motor is friction fit and the clear tape holds the two stages together.

 

[Jack Arne]

Exactly. Each motor is friction fit and the clear tape holds the two stages together.

Is it okay if the body of the first stage covers 1/2” of the second stage engine to make the bodies touch together?

 

[neil_w]

Is it okay if the body of the first stage covers 1/2” of the second stage engine to make the bodies touch together?

No problem, that is typical.

 

[Jmhepworth]

Is it okay if the body of the first stage covers 1/2” of the second stage engine to make the bodies touch together?

Exactly. That’s how it works. Let’s talk in terms of the booster and the sustainer. The sustainer needs to have about a quarter inch or so of the motor stick out the aft end or you could never get the sustainer motor out after it’s spent. And it would burn the sustainer if it doesn’t stick out a little. If you put the motor block in the right place, the sustainer could be used just like a single stage rocket. When you do it as a two stage, the booster covers up that part of the sustainer’s motor. Use only enough clear tape to hold the motors together. You don‘t want the booster to be friction fit to the sustainer motor by the clear tape. The booster might get singed a little. Two stages are fun.

 

[CoachSteve]

Here are a few picts - not sure if they help?

 

[Jmhepworth]

Looks great. When are you flying it?

 

[BABAR]

Yes.
Instructions could be better, I have linked them here
https://estesrockets.com/wp-content/uploads/Instructions/003227_LOADSTAR_II.pdf
Looks like Loadstar uses the motors as the COUPLER, an overlapping section that keeps the booster and sustainer (first and second stage in your terminology, and the instructions refer to the sustainer as the second stage. Both your terminology and that of Estes is correct, I prefer Booster and Sustainer as, at least for two stage rockets, helps me keep ‘em straight in my head) attached and aligned from launch to separation.

Assuming you put each engine block in the right place (the Booster at the tail end of the Booster Engine Mount Tube, and the Sustainer [aka Second Stage] the right distance forward inside the Sustainer Engine Mount Tube), with the two motors taped fit should automatically be perfect if you slide the taped motors into the sustainer all the way to the motor mount (BE SURE BOTH THE NOZZLES FACE THE REAR AND MAKE SURE THE RED MOTOR IS IN THE BOOSTER AND THE PURPLE OR GREEN SUSTAINER MOTOR IS IN THE SUSTAINER! EXPERIENCED ROCKETEERS HAVE SCREWED THIS UP!!!!!!). It is worth using a Sharpie to write “BOOSTER” and “SUSTAINER” and an arrow pointed forward from the nozzle to the forward end on the motors to make sure you get this right

 

[CoachSteve]

the 3 stage has already gone up once - D12, B6, B6-6 - lost the sustainer, rebuilt it and it is ready for the next go
the Xarconian Cruiser has not been up yet - and with launches shut down ??
I also 2-staged an Estes Odyssey to (kind of the good guy ship to go with the bad guy Cruiser)

 

[Zeus-cat]

Make sure the booster motor has a zero at the end; such as B6-0. The zero indicates it is specifically made for a booster stage motor and has no ejection charge. When the motor has nearly exhausted its fuel the top of the motor grain fractures and sends burning particles up into the nozzle of the second stage and ignites that motor.

Use the lowest recommended motors for the first two stage flight or you may not see the upper stage land.

Also, make sure you put both motors in with the nozzle end at the bottom. Apparently, not doing this is a common two stage failure mode for new people.

 

[Jack Arne]

Use only enough clear tape to hold the motors together. You don‘t want the booster to be friction fit to the sustainer motor by the clear tape. The booster might get singed a little.

How do you make sure the clear tape portion doesn’t friction fit the booster to the sustainer? I’m worried it will not disconnect...

 

[neil_w]

Don’t worry, the sustainer motor will blow that right off. Just one wrap of scotch tape and you’re good to go.

 

[Chris Brewer]

I am also building a multi stage, specifically the Comanche 3. It uses couplers to line up the boosters and sustainer. How tight should they fit together? Obviously you do not tape the stages together as the flame would not reach the tape through the couplers.

 

[BABAR]

They only NEED to be tight enough to prevent any lateral waggle of any of the stages.

But for practical purposes, if you have all three properly arranges ready for flight, you should be able to grab the sustainer below the nose cone (don’t accidentally pull out the cone) and GENTLY lift the rocket straight up and the stages should stay together. If you quickly pull the sustainer straight up, the two boosters should separate just from gravity and inertia. Similarly, if you grabbed it by the mid booster and quickly pulled up, the lowest booster should come off.

Remember that (for black powder staging, which is what Comanche uses) IN FLIGHT the currently lit booster is pushing UP while gravity and air resistance are pushing the whole rocket (especially that above the lit booster) DOWN. So The inflight forces are holding everything together from front to back, the coupler is only needed to prevent lateral motion.

 

[Zeus-cat]

The Comanche 3 often becomes the Comanche 2 after a few launches. Or the Comanche 0 in a few cases when things go terribly wrong. I have never built one, but the ones I have seen launched have not fared well. Use small motors in the upper stages to keep the weight and altitude down. And fly it only when it is calm; wind is an enemy to a three stage rocket.

 

[Chris Brewer]

OK that’s what I thought should happen with the boosters. Thank you for the Responses. I will be using smaller engines in the second booster and the sustainer

 

[Jmhepworth]

I will be using smaller engines in the second booster and the sustainer

Sure you will. Until the second launch when you say wouldn’t it be fun to see how high it can go. We all do that.

 

[BABAR]

OK that’s what I thought should happen with the boosters. Thank you for the Responses. I will be using smaller engines in the second booster and the sustainer

Absolutely concur with lowest possible motor power on sustainer and for a three stage the second booster.

Funny story about flying the Apogee II , and Estes 2 stage, with my Dad in the 70s. Booster was. B6-0, I don’t remember what we put in sustainer.

Light winds.

Pushed the button, both of us watched the launch with the rocket zooming off the pad, straight up, arcing overm parachute deploying, watched it come down maybe 75 yards away.

Scanning the sky, never saw the booster, never saw the staging event, looked all AROUND us (clue here) for the booster. Pretty flat ground, not too bushy, could not see the booster.

Went and got the sustainer, came down as nice as you please, no damage.

Gave up looking for booster.

Went to pack up.........


There, at the base of the launch rod, sitting on the pad, was the booster.

Apparently it successfully staged before it left the rod, and slid back down the rod onto the launch plate.




Have a great flight, hope you get three straight trails and short walks.