NX Kuiper RLV B (Rocket Launch/Lift Vehicle) - Newbie Input

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Jonathan 7

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Hi! I’m new to the forum and would love any input, comments, and/or suggestions for improving my Rocket (my first scratch build). It has multiple configurations, including lifting/launching a glider at apogee. I would love to make it cooler!

It is a two stage Rocket with an optional third stage. The booster takes a D12-0 and the second stage is a cluster of two 18mm motors. They are two for two for air-starts!

Anyway, one 18mm 2nd stage motor ejects the parachute (teal recovery bay with a 12.5 in Estes parachute) and the other 18mm motor can either eject a glider or another small rocket with a BT-20 body - or it can launch it as a third-stage! I’ve only launched twice; I haven’t tested a third-stage air start yet. I plan on trying this weekend.

The glider separates beautifully and it glides like the Space Shuttle. The large elevons offset the weight very well. I intended the glider to double as an autonomous boost glider, with rear ejection, but it failed twice.
 

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JJSR

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Thats a realy COOL rocket now,
I'm not sure what you could add to it though,, its over the top already
 

Jonathan 7

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Thats a realy COOL rocket now,
I'm not sure what you could add to it though,, its over the top already

Lol, thanks!

One thing is, is there anything I could use to prevent burn damage? If you look at the third stage coupler, you can see that the varnish is burned, as are the rocket and glider, aft.
 

JJSR

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Maybe high heat engine paint or some of that metal tape they use for duct work. ?
 

dhbarr

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I'm not qualified to form an opinion on these types of things, just wanted to say I really appreciate the originality on display.
 

BABAR

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You have what I all a Chimera, a monster of mixed rocket types rolled into one, and you made it work! Very impressive. If I read you right, you are using one D12 booster to ignite two black powder sustainers, which is also a challenge (a split gap stage.). Again, kudos.

For your scorching, on the painted surfaces consider putting a strip of transparent cellophane tape over an area moderately larger than your scorch mark, and then put a piece of Mylar tape over the area itself. The Mylar tape should prevent scorch burn through, but it will blacken and wrinkle. The transparent tape allows you to pull off and replace the Mylar tape when it gets discolored enough to bother you, WITHOUT pulling off your paint when you yank the Mylar off.

For the coupler, what are you using? An engine casing or a smaller caliber body tube or a “real” coupler? I am too cheap to but couplers so I make them with same size body tube, cut out a section and roll to fit. You can try high temp paint. Also can put Mylar on the outside. Both will make the outer diameter of the couple a bit larger, which may make it too tight, you may need to sand it down.

I would like to see some pictures “down the barrel” of your booster showing the “plumbing” between single booster and two sustainer engines. I have done one to three, haven’t tried one to two.

Again, nice work. Would like to see a flight video with booster igniting the sustainer and launching the glider!
 

Jonathan 7

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You bet! See the attached pics. The adapters are real - I don’t like to cut tubes unless I have to.

I’m going to try and do some more launches tomorrow. Hopefully I can get it on video this time - I had mysterious camera issues the last two times. It was like some force was trying to prevent vids of just that rocket!

As to the motor sequence, yes, you will see it is a D12-0 booster that lights two 18mm black powder motors, and one of those can light a third stage.
 

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BABAR

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So not “ducting” of the D engine plume up to the two upper stage motors? Just stick the in front? That is soooooo much simpler than mine, I didn’t think it would work.

What is the actual gap space when loaded between forward edge of booster casing and the nozzles of the upper engines?

Also, what is estimated altitude for staging with booster config? Given it is launch on a zero delay, I didn’t figure it would be very high?
 

Jonathan 7

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The actual gap is 0.75 inches. No ducting, but only a partial bulkhead on the second stage. Between the holes in the booster stage and the partial bulkhead on stage two, it won’t separate unless and until the second stage engines start. So, you’ll notice the severe ablation in the top of the first and the core of the second. It’s an inferno inside there at staging.

I don’t have actual data on staging altitudes b/c we twice had the altimeter (trigger) too close to the pad - it goes higher than it is predicted to.

PS The estimated altitude at booster burnout/stage sep is 175ft, but I'm not sure how accurate that is.

PPS there is “some” ducting. The booster engine block (green ring) does somewhat concentrate the sparks from the first stage D12-0.
 
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Jonathan 7

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It’s a little hard to see, but this is the top of the second stage partial bulkhead. You can see down the barrel of the third-stage ignition tube.
 

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BABAR

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Nice! I want to thank you for posting this, I think I may steal your staging anatomy (I hope you understand the “imitation is the best form of flattery” :smile:) for my remodel of the Estes MIRV. Next one up on my scratch bench will be a single D booster to three motor A cluster single sustainer. It will also help with my single D booster to two glider (think MPC Lunar Patrol) and single airbrake recovery A engine sustainer.


What engines did you use for the dual upper stage ignitions? I usually start with As (bigger nozzle, easier to light) and move up to B or C sometimes . Other reason I stay with As other than bigger nozzle is makes it a heck of a lot easier to FIND multiple sustainers if you don’t shove a C in there and send them up to 600 feet (or more.).
 

Jonathan 7

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Nice! I want to thank you for posting this, I think I may steal your staging anatomy (I hope you understand the “imitation is the best form of flattery” :smile:) for my remodel of the Estes MIRV. Next one up on my scratch bench will be a single D booster to three motor A cluster single sustainer. It will also help with my single D booster to two glider (think MPC Lunar Patrol) and single airbrake recovery A engine sustainer.


What engines did you use for the dual upper stage ignitions? I usually start with As (bigger nozzle, easier to light) and move up to B or C sometimes . Other reason I stay with As other than bigger nozzle is makes it a heck of a lot easier to FIND multiple sustainers if you don’t shove a C in there and send them up to 600 feet (or more.).

I’m thrilled! That’s why I joined this forum - to exchange ideas.

I use two Bs in the second stage; but you’re right, it does go too high. I was originally going to use C6-7; glad I didn’t do that.

Funny, I was thinking of building the Estes MIRV. I do like those little A10-3Ts. I hope you put your version here to see!

Question: what mechanism is best to effect an air brake recovery? I’ve never done one.
 

BABAR

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I built the Estes MIRV
https://www.rocketryforum.com/threads/estes-mirv-sort-of-a-build-thread.138977/
Personally found booster woefully underpowered , and I lost all three sustainers are first launch (arced directly into a light wind, altitude 50 feet, distance a couple hundred feet laterally.). Maybe I just build or finish heavy. I like Estes stuff, but I didn’t like this actual rocket. I DID love the CONCEPT, which is why am working on a heavily modified version, D to A. I am also not sure the sustainers are REALLY stable, although it doesn’t matter that much because they SHOULD be up high and engines burn out fast. Note: on my scratch two stages the upper stage is always stable and could potentially be flow as single stage.

For any first flight18mm two stage I recommend for sustainer an A engine (A8-3...... or A8-5, if you can find it.). Larger nozzle is more reliable, and for first flight you just want to see if it will work, not go for orbit. I hate losing a bird on its first flight, Also IMO a safety issue, in an untested scratch two stage, while you shouldn’t FLY it if you don’t feel based on experience or sims that it is stable, on the off chance my bird is not vertical at staging, I’d much rather have a weaker than stronger engine.

My airbrake rockets are basically helicopters with no tilt on the rotors. Some of them spin a little bit, but intent is for them to come down flat.

Here is a build

https://www.rocketryforum.com/threa...uilt-thread-air-brake-recovery-rocket.145077/

Back to your rocket. I see four tubes coming off the forward end of your booster. Two are for the upper stages, what about the other two?
 

Jonathan 7

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I built the Estes MIRV
https://www.rocketryforum.com/threads/estes-mirv-sort-of-a-build-thread.138977/
Personally found booster woefully underpowered , and I lost all three sustainers are first launch (arced directly into a light wind, altitude 50 feet, distance a couple hundred feet laterally.). Maybe I just build or finish heavy. I like Estes stuff, but I didn’t like this actual rocket. I DID love the CONCEPT, which is why am working on a heavily modified version, D to A. I am also not sure the sustainers are REALLY stable, although it doesn’t matter that much because they SHOULD be up high and engines burn out fast. Note: on my scratch two stages the upper stage is always stable and could potentially be flow as single stage.

For any first flight18mm two stage I recommend for sustainer an A engine (A8-3...... or A8-5, if you can find it.). Larger nozzle is more reliable, and for first flight you just want to see if it will work, not go for orbit. I hate losing a bird on its first flight, Also IMO a safety issue, in an untested scratch two stage, while you shouldn’t FLY it if you don’t feel based on experience or sims that it is stable, on the off chance my bird is not vertical at staging, I’d much rather have a weaker than stronger engine.

My airbrake rockets are basically helicopters with no tilt on the rotors. Some of them spin a little bit, but intent is for them to come down flat.

Here is a build

https://www.rocketryforum.com/threa...uilt-thread-air-brake-recovery-rocket.145077/

Back to your rocket. I see four tubes coming off the forward end of your booster. Two are for the upper stages, what about the other two?

The other two tubes are pseudo tube fins, as well as anchor points for hold-down pins. I couldn’t do a transition from the BT-60 to the two BT-20s for myriad reasons. It would have screwed up the design. So I have those pseudo tube fins to add to route some air and because there are two launch lugs on the glider elevons. To hold down the elevons, you pass pins through the lugs, and then into those tubes. Viola!

Major wind today. Ugh. Not going to risk a launch.
 
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Jonathan 7

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Smart Man!

Just got some more parts. I think I’ll do a 2.0 build on this one. And on the glider. The only issue with gliders is that they use SO MUCH wood.

In the interim, I’ll put the plans for this one up on the forum.
 

BABAR

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Just got some more parts. I think I’ll do a 2.0 build on this one. And on the glider. The only issue with gliders is that they use SO MUCH wood.

In the interim, I’ll put the plans for this one up on the forum.
Hobby lobby coupon. Gets you a 6x36” (152 x914 mm for you Aussies) sheet of 1/8” (3mm) for $4-$5.

If you paper it, make sure you keep track of grain direction
 

Jonathan 7

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Hobby lobby coupon. Gets you a 6x36” (152 x914 mm for you Aussies) sheet of 1/8” (3mm) for $4-$5.

If you paper it, make sure you keep track of grain direction

Oh... can you recommend a CAD program for Mac for design? I use OpenRocket to simulate, but I don’t have a program for CAD. Free is good, if any
 

BABAR

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Me no speak CAD. All my stuff is pencil and paper, although I do use my phone calculator for sin and cosine functions when I need to calculate dimensions on angled stuff.

I mind-sim the rockets before I build them, and usually test launches are done with no one else around, so if things don’t go as planned, all I suffer is disappointment. Since I don’t fly anything over a G (actually been a few years since I even flew an E) this works for me pretty well,
 

Jonathan 7

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Me no speak CAD. All my stuff is pencil and paper, although I do use my phone calculator for sin and cosine functions when I need to calculate dimensions on angled stuff.

I mind-sim the rockets before I build them, and usually test launches are done with no one else around, so if things don’t go as planned, all I suffer is disappointment. Since I don’t fly anything over a G (actually been a few years since I even flew an E) this works for me pretty well,

I’m old-school like that too - experimentation over simulation. And I’ve never flown anything beyond D12. I don’t speak composite or huge, load able motors with fiberglass sustainer cores. And projects like BPS.space, thrust-vectoring and propulsive landings... I don’t consider that to even be the same hobby. That’s not true model rocketry to me.
 

Jonathan 7

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Is your Avatar an actual flown rocket!?

I’m trying to think up ideas for a 2.0 of this Chimera. I may even call it the Chimera! Any suggestions for an encore? I need a challenge objective :D
 

Jonathan 7

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Is your Avatar an actual flown rocket!?

I did some studies (uncompressible flow), to learn about CAD and its usefulness in model rocketry. I created a model in inventor of this rocket (subject of this thread), and I was able to locate the center of pressure (force) in Autodesk CFD with pretty decent accuracy (compared to actual flights). The wind is coming in at 20 degrees to the Y-Axis (the angle of attack here) at 200 ft/s. I did a wall study to find the approximate CP (see the red points).

Now that I'm somewhat familiar, I'm going to try and see the dynamics of the staging and successful three-stage air-starts (internal flow)!
 

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Nytrunner

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By what calculation or variables did you estimate the CP location? And did you run cases at multiple AoA orientations to account for the rocket asymmetry?
 
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