Neil_W's half-baked design thread

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Alpha III Hal 2001 Edition.. Single and Double

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Definite cool factor.

The tail looks a little bit like a mix between a ring fan and a true saucer.

Are the rings really that thick?

I like the open space in the middle as it definitely will have airflow over your Alpha’s dins so they should be effective from the get go, not having to clear the “wash“ from a “true” or closed saucer section. Something that might make this a little bit more fun. Put some “windows“ on the lateral edges of the rings next to the fin attachment sites, only on the clockwise or anticlockwise sides. When this falls after separation it will cause these to rotate and you will get a Magnus effect.
 
I did the Saucer booster stage / traditional sustainer. The booster was from an Estes twin factor, i have no video evidence but the staging was fine and straight On the 3 flights it had. the sustainer was poorly made, The fins were Estes paper mat board material and coated in 5 min epoxy, they warped like crazy just from sitting on the shelf, I have since scraped the sustainer, haven’t made a replacement. Sorry About the microscopic pictures

Quirky two stage


EC22E821-ACC4-4561-A327-D69FBF813A49.jpeg 4E8CB4FA-CE83-49E6-8E15-3C652D6B2BDC.jpeg
 
when I originally built it I thought something draggy would be a better fit, less draggy than the saucer but more so than fins. Something like dowels maybe? Sketch isn’t scale but assume it’s a bt-50 for the sustainer. does this heat up the back burner at all?
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Thanks mbeels! Since we’re talking saucers I‘ll share one more design in neils thread. This is another mini engine rocket so you can gauge size from there, the alien is a lego mini figure, mindsim has me a little worried about stability but it looks so good.
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I thought the Lockheed XB70 discussed in another thread looked cool, so I took a crack at it in OR. Two key observations:
1) It really needs a ribbed body a la Marten's Boom XB1. The arch of the body over the wing is really a key part of the look. Also, I wanted the tail to look the same as the real thing (6 motors in a line), with the middle two actually being motor mounts. There doesn't seem to be any reasonable way to approximate that in OR.
2) I realized after a while that the whole design is remarkably similar to the carrier in the Orbital Transport. Yeah, there are differences, but the broad strokes of the design are all pretty much in sync.

And so, the result is not bad, but I don't expect to pursue it further.
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The arch of the body over the wing is really a key part of the look.

Totally. But cool.

It's nearly cylindrical enough that I wonder if a body tube and long transition would get the effect. But details like motor ejection and recovery get complicated.

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I thought your wings looked small, so I went looking for drawings rather than pictures.
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On the way I discovered something else.
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It appears the Concorde SST may have owed a little to the XB-70.
 
I didn't mean it as criticism, just the reason I went looking.

It would be very challenging to make the canards into working control surfaces, but that certainly would let one solve the CP/CG relationship problem, and possibly even make it recoverable as a glider. Would be awesome if one could pull it off.
 
I thought the Lockheed XB70 discussed in another thread looked cool, so I took a crack at it in OR. Two key observations:
1) It really needs a ribbed body a la Marten's Boom XB1. The arch of the body over the wing is really a key part of the look. Also, I wanted the tail to look the same as the real thing (6 motors in a line), with the middle two actually being motor mounts. There doesn't seem to be any reasonable way to approximate that in OR.
2) I realized after a while that the whole design is remarkably similar to the carrier in the Orbital Transport. Yeah, there are differences, but the broad strokes of the design are all pretty much in sync.

And so, the result is not bad, but I don't expect to pursue it further.
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Reminds me of the Estes "Orbital Transport" mothership.
Orbital Transport.jpg
 
OK, it's been almost 2 months since I've even opened OR with intent of working on a design. I was finally moved to do it by @H. Craig Miller 's insane Anti-Virus build, which in just about every way put my old Moonshot design to shame. So I needed to up my game there and make it more interesting, taking a lot of inspiration from his design.

Here's how it used to look:
moonshot.png
I added some detail, adjusted the dimensions, updated the decals, and made it a two-stager:
moonshot_side.png

moonshot_composite.png

It's fairly small at 23+", but looks like it should just barely be able to boost on a B6-0 or C6-0 with a 48" rod, provided I can really carefully manage the mass and CG. The plunger handle in the back is the booster; it would be a short gap-staged design. It appears to be stable even without the two rings factored in; those should give me additional margin, and maybe allow me to reduce the nose weight. Like many designs it would be better larger, but I like the idea that it'll run on 18mm motors.

I actually purchased parts to build this (well, the old version, but the parts don't change) a while ago; have to convince myself that it's interesting enough to go forward with. It would be a fun rocket when completed, but it's not a very interesting build compared to the other stuff I've done recently. We'll see.
 
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I added some detail, adjusted the dimensions, updated the decals, and made it a two-stager:

I really like the two-stage idea, with the plunger popping out as the first stage. That would be fun to watch.

It would be a fun rocket when completed, but it's not a very interesting build compared to the other stuff I've done recently. We'll see.

Perhaps, but fabricating that nose cone doesn't look trivial, and I bet it'd be a hit with the spectators.
 
Perhaps, but fabricating that nose cone doesn't look trivial, and I bet it'd be a hit with the spectators.
Yes, fun rocket, not-so-much-fun build. The nose cone is just a conical balsa cone with a decal on it. I'm sure I could spend some time fussing over the needle hub, but overall there's not much to it. Not a good winter build.
 
If you want more of a build challenge, try this ridiculous notion.

It's single stage. The plunger starts in the position shown, but slides up when the motor lights and actually squirts some colored water out the top.
 
Perhaps, but fabricating that nose cone doesn't look trivial, and I bet it'd be a hit with the spectators.

Use a wooden dowel for the needle. The remaining nose cone would be easily turned on a lathe. If you decide to build this rocket I'd be glad to make it for you Neil, Pro bono.
 
Use a wooden dowel for the needle. The remaining nose cone would be easily turned on a lathe. If you decide to build this rocket I'd be glad to make it for you Neil, Pro bono.
Greatly appreciate the offer, but that's actually plain old BT5 and a conical nose cone I've already purchased. It's a bit thick compared to what the real needle would be, obviously (dock me points for scale accuracy) but as far as I'm concerned looks pretty good.

I've been working through the details on this design. Here's the current side view, shown with C6-0 => C6-3.
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It's like a festival of centering rings. The challenge is that it is flirting with the max lift-off weight of the C6-0, and I will need to be extremely careful to avoid adding any excess mass. The sustainer is also a bit marginal with regard to stability (running around .8 right now), but since it would be starting at 100 mph it seems like it should be OK. Also it's a bit of a guess since the tail rings aren't factored into CP (I have put some compensation into the model, but accuracy is unknown). Need to avoid adding nose weight if possible. As it is, speed off the rail with C/C is just under 50 fps.

If I limit the sustainer to a B6, I buy a little margin back, but I'd *like* to be able to fly the C/C stack, which sims to about 800 ft, plus or minus.

Hey, here's a weird thing. Look at this plot for the C/C flight:
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First of all I need to figure out what I did to make the sim stop at apogee. But anyway, look at the circled portion of the velocity plot. Basically, after the initial thrust spike of the sustainer motor, the rocket almost hits terminal velocity at around 140+ mph. Somehow I find that really surprising; the sustainer is only modeled at 2.7 oz with motor, and doesn't look *that* draggy to me, certainly nothing like a lot of other more complex models. An earlier version of the sim, actually showed the velocity slightly *decreasing* during that period, don't know what changed.

Anyway, this flight stages at about 170 ft and 105 mph, then on up to 800 ft, which seems pretty good to me.
 
Greatly appreciate the offer, but that's actually plain old BT5 and a conical nose cone I've already purchased. It's a bit thick compared to what the real needle would be, obviously (dock me points for scale accuracy) but as far as I'm concerned looks pretty good.

I've been working through the details on this design. Here's the current side view, shown with C6-0 => C6-3.
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It's like a festival of centering rings. The challenge is that it is flirting with the max lift-off weight of the C6-0, and I will need to be extremely careful to avoid adding any excess mass. The sustainer is also a bit marginal with regard to stability (running around .8 right now), but since it would be starting at 100 mph it seems like it should be OK. Also it's a bit of a guess since the tail rings aren't factored into CP (I have put some compensation into the model, but accuracy is unknown). Need to avoid adding nose weight if possible. As it is, speed off the rail with C/C is just under 50 fps.

If I limit the sustainer to a B6, I buy a little margin back, but I'd *like* to be able to fly the C/C stack, which sims to about 800 ft, plus or minus.
Here’s hoping Estes comes out with a C5-0 in the near future. Should just about double the max lift off weight compared to C6-0
 
Here’s hoping Estes comes out with a C5-0 in the near future. Should just about double the max lift off weight compared to C6-0
That would be nice, but I've not heard that it is coming, so I can't assume. Not sure why, it seems like such an obvious use for that motor.
 
Somehow I find that really surprising; the sustainer is only modeled at 2.7 oz with motor, and doesn't look *that* draggy to me, certainly nothing like a lot of other more complex models

I did a really quick dirty estimate of the drag force at 150 ft/sec, for a 1.6" diameter rocket and Cd = 0.75, and it comes out to about 4.5 Newtons, just about the same as the thrust of a C6 during the tail end of the burn. I'm not sure it is right (it probably isn't), but it makes it seem kind of reasonable.

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Here’s hoping Estes comes out with a C5-0 in the near future. Should just about double the max lift off weight compared to C6-0

It might help with getting off the rail, but that initial thrust spike is followed by 1.6 seconds of about 1/2 the thrust of a C6, so that may not help the over all picture as a booster motor, trying to over come the drag and weight of two stages.

https://www.thrustcurve.org/motors/...2310000000014&motors=5f4294d20002310000000015
If there were room for it, a C11-0 would make a great booster, but it would take a 24mm motor mount.

https://www.thrustcurve.org/motors/...231000000001a&motors=5f4294d20002310000000015
 
After some further playing, it does seem as if the design, as entered, has almost the exact drag required to equal the thrust. Interesting. The real thing will almost certainly be draggier than the model, which means it will indeed be likely to decelerate during the main thrust phase of the sustainer.

I guess that's OK?

Regarding the booster motor, I *could* put a 24mm mount back there, but I don't really *want* to, because it'll require the aft tube to move up to BT50. I guess I should at least try it in the model to see how it looks and works.
 
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