Mitsubishi H-2A , Anyone build a rocket with pods no fins?

[Nick@JET]

Thinking of building a 5” rough scale of the Mitsubishi H-2A , Anyone build a rocket with pods no fins? It would have Base drag or maybe a couple clear fins.

I’ve worked for Mitsubishi for a long time and after flight I may give to our management for display - but just a thought right now.

Any suggestions on fin design?



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[Andrew_ASC]

You could always try fin-less. It's been done but it's rare. Takes a lot of guts and bravery to launch something different.

 

[Andrew_ASC]

I think you could slightly cant the pods to spin stabilize it. It would be wacky method to do that.

 

[tim cubbedge]

Not that particular rocket but similar. Lexan was used for fins.


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[dhbarr]

As long as you do a 204 it should work fine without any add'l fins. The 2024 could maybe also work, but I expect it would be trickier.

I would only use one central motor and leave the pods for show. Good luck!

 

[OverTheTop]

Is nose-weight an option? Use that and no fins if you can tolerate the extra mass (depends on motor you intend to fly with). I would suggest to the RSO that the first flight be a "heads up" flight also.

 

[Thorfire]

If it was built light enough, could you use a thrust vectored I49 as the central motor of a cluster with a modified Signal Alpha unit?
https://bps.space/signal-alpha/

 

[LithosphereRocketry]

If it was built light enough, could you use a thrust vectored I49 as the central motor of a cluster with a modified Signal Alpha unit?
https://bps.space/signal-alpha/

Oooh, I like that idea!

 

[Salvage-1]

surface area to weight distribution.... if the cog is far enugh forward, the pods should act like fins by the extra surface area of the rear of the rocket...... or... pods = tube fins!

 

[mikec]

Lexan fins are really not very noticeable -- see attached picture of my Atlas V on the pad.

 

[ksaves2]

Oooh, I like that idea!

I think it's over $300.00 and I don't know if it could handle the mass of the outboard pods but you're right, it's pretty cool. What I found fascinating was when the
motor burns out, the rocket tube starts a slow tumble and I believe that helps cut down on deployment stresses. I would'a thought the tube would keep going
straight but no way. It starts a gentle tumble after burnout.

I had a rocket once where stupidhead forgot to connect the quicklink to the upper bay. The upper bay with the main chute and nosecone I thought was going to
zipper to bits. You know, come straight in nose first. Well, I didn't see that part of the rocket and was fixated on the fincan coming in hard under the drogue.
Eventually I saw the 6 foot main open and that part of the rocket was pristine. It was a 4" cardboard tube and not a mark on it. The fincan buckled in the middle
but I was able to straighten it out and restore it with a fiberglass wrap.
Finally got that rocket to fly right. (That's the one in the avatar above with my lovely spouse who you can tell by her scowl just barely tolerates my eccentric hobby.)
Kurt

 

[Nick@JET]

Lexan fins are really not very noticeable -- see attached picture of my Atlas V on the pad.
View attachment 335180

Looks great Mike - I especially like that transition into NC - is that a kit ?



Thanks for all the responses - I’ve considered lexan fins / tube fins instead of pods - all good things to consider. I watched the video of a launch and that is 3 engines - outer white lightening and the inner not sure. Also not sure how far I’ll go to make the launch a replica instead maybe just a single engine and a look alike - especially for possibly only a single flight, or I just display it instead of giving it to them.


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[OverTheTop]

Finally got that rocket to fly right. (That's the one in the avatar above with my lovely spouse who you can tell by her scowl just barely tolerates my eccentric hobby.)

I don't think my wife would even hold one of my rockets.

 

[mikec]

Looks great Mike - I especially like that transition into NC - is that a kit ?

Thanks. No, it's scratch-built, based on upscaled vinyl wraps from the great paper models of the Atlas V at https://axmpaperspacescalemodels.com/index.php/atlas-v/

Good luck on the H-2A, that looks like a great scale subject. BTW, note that Dragon Models makes a 1:400 plastic model of the H-2A that might be useful for scale details.

 

[LithosphereRocketry]

Thanks. No, it's scratch-built, based on upscaled vinyl wraps from the great paper models of the Atlas V at https://axmpaperspacescalemodels.com/index.php/atlas-v/

Good luck on the H-2A, that looks like a great scale subject. BTW, note that Dragon Models makes a 1:400 plastic model of the H-2A that might be useful for scale details.

Just one more Atlas V question- what SRB config is it, and are the SRB locations in scale? I know the Atlas V has some pretty weird arrangements to get around the stuff on the sides... Now I want someone to do a 1 booster Atlas with an outboard.

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[mikec]

Just one more Atlas V question- what SRB config is it, and are the SRB locations in scale? I know the Atlas V has some pretty weird arrangements to get around the stuff on the sides... Now I want someone to do a 1 booster Atlas with an outboard.

Not to hijack Nick's thread, but to answer the question: my model is a 2-SRB configuration, but I cheated by making the boosters symmetric. But I have had flights when only one SRB's motor ignited. The rocket survived but it's not a configuration I would want to fly intentionally (maybe you could angle the core's motors to compensate for the off-axis thrust like the full scale vehicle does.)

Looks like the H-2A's SRBs are even farther outboard than the Atlas's, so flying it as a cluster might be a little iffy.

 

[LithosphereRocketry]

Not to hijack Nick's thread, but to answer the question: my model is a 2-SRB configuration, but I cheated by making the boosters symmetric. But I have had flights when only one SRB's motor ignited. The rocket survived but it's not a configuration I would want to fly intentionally (maybe you could angle the core's motors to compensate for the off-axis thrust like the full scale vehicle does.)

Looks like the H-2A's SRBs are even farther outboard than the Atlas's, so flying it as a cluster might be a little iffy.

So now that I've seen an Atlas V 411 launch (there was one the other day) and witnessed the true wonkiness of one SRB, I want to build one. Do you happen to have basic scale data handy for the Atlas 400 series? I'm not super picky, I just need some basic dimensions, and if it's not handy I can measure the paper model. I'm thinking 2 18mm motors in BT-60 with a canted 13mm outboard.

 

[mikec]

So now that I've seen an Atlas V 411 launch (there was one the other day) and witnessed the true wonkiness of one SRB, I want to build one. Do you happen to have basic scale data handy for the Atlas 400 series?

Attached is the ORK file for my Atlas V 521; note that because OR doesn't manage pods this is kind of a kludge. Also, OR can't model the nose cone shapes. You will have to scale off the drawings you can find in various documents or images on the internet. All in all, it may be easier for you to start with the paper model.

View attachment atlasv3d.ork

 

[bill_s]

I've built finless rockets. One issue is little damping, any wobble tends to continue. Plus lots of nose weight needed. Base drag stabilization is a myth. Open Rocket will calculate it if it will build it, but is an optimist (even though it doesn't consider base drag, again it's a myth).