Gliding Booster Pods

[jqavins]

There are a good few ways of making booster pods that fall away from the main body of a rocket at their own burnout, and as far as I know they either fall, or come down on parachutes or streamers. Has anyone made them to glide down? It seems like that might not be too difficult.

 

[sr205347d]

You could do mini Starship gliders.

https://www.rocketryforum.com/threads/starship-glider.184449/

 

[David_Stack]

I think the old Centuri Black Widow had a booster that was supposed to return via glide…

Reading accounts here on the forum, it sounds like there are varying degrees of success…

 

[jqavins]

I think the old Centuri Black Widow had a booster that was supposed to return via glide…

Reading accounts here on the forum, it sounds like there are varying degrees of success…

My bad, I left out key words: strap-on boosters. The rocket takes off as a three motor cluster, the side boosters drop away while the central motor is still burning, and the boosters come down, usually either tumbling or under chute/streamer. But I want strap-ons that become gliders when released.

The gliders' wings and tails would all just be fins to the full stack. It should be easy. Easyish.

 

[sr205347d]

The Apogee Flying Machine has booster pods that you could put delta wings on.

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-4-Model-Rocket-Kits/Flying-Machine

Or similarly, the Apogee Strap-on pods could be modified with wings.

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-4-Model-Rocket-Kits/Flying-Machine

 

[Raythain]

My bad, I left out key words: strap-on boosters. The rocket takes off as a three motor cluster, the side boosters drop away while the central motor is still burning, and the boosters come down, usually either tumbling or under chute/streamer. But I want strap-ons that become gliders when released.

The gliders' wings and tails would all just be fins to the full stack. It should be easy. Easyish.

You’re thinking a parallel staged version of the ARV Condor then? That sounds amazingly cool.

Could probably modify it to release the gliders like the Apogee strap-on boosters. Would also need to make space for some fins on the main stack.

 

[jqavins]

So, to my original question, none of you who've responded (and thank you) are aware of it having been done, is that right?

Maybe I'll attempt it. Maybe I should build some other glider first. Maybe I should finish the other three big projects on my desk first. Yes, I should finish those first.

 

[KenECoyote]

May be hard to track, especially if more than a single booster glider. Sounds very cool though.

 

[jqavins]

As with anything staged or or boost gliders, or any such thing, you should have one spotter per separated piece.

 

[ReynoldsSlumber]

IRL, DLR proposed liquid fly-back boosters for the Ariane 5, among similar proposals for other launchers.


Would be pretty darn cool on the Orbital Transport to convert the booster to glide back as the parasite glider does. Would likely mean enlarging the little canard foreplanes into functioning ones.

 

[mjennings]

I don't recall ever seeing glide back boosters, trick will be detaching them and adjusting the cg for glide. Sounds fun can't wait to see what you come up with.

 

[jqavins]

I don't recall ever seeing glide back boosters, trick will be detaching them and adjusting the cg for glide.

Well, here's why I think it should be easyish.

Detaching is a problem that a few people have solved, in a few ways. So, build a glider - body tube, wings with a little dihedral, tail section, nose cone - with a motor mount and trimmed with spent motor installed. Simple. No shifting the CG or the CP, no moving parts at all except whatever is involved in the release from the main rocket.

But the main rocket is a lot taller than the booster, so when the booster is attached to it, all those surfaces that make the glider work are just lots of oddly placed fins. The rocket after separation is just a 4FNC. Before separation it has a bunch of extra weight aft, and a bunch of extra fin area to help compensate for it.

I won't say it's altogether easy, because I'm not that naive. But I think it sounds simpler than most glide recovery designs, because you don't have to adjust the CG for glide.

 

[mjennings]

Well, here's why I think it should be easyish.

Detaching is a problem that a few people have solved, in a few ways. So, build a glider - body tube, wings with a little dihedral, tail section, nose cone - with a motor mount and trimmed with spent motor installed. Simple. No shifting the CG or the CP, no moving parts at all except whatever is involved in the release from the main rocket.

But the main rocket is a lot taller than the booster, so when the booster is attached to it, all those surfaces that make the glider work are just lots of oddly placed fins. The rocket after separation is just a 4FNC. Before separation it has a bunch of extra weight aft, and a bunch of extra fin area to help compensate for it.

I won't say it's altogether easy, because I'm not that naive. But I think it sounds simpler than most glide recovery designs, because you don't have to adjust the CG for glide.

Solid plan, wings might need to be a bit larger to get the wing loading down to account for the spent motor weight. Should be interesting!

 

[Capt. Eric]

Problem with using the Apogee strap on booster mechanism is that the nose cones have to separate to allow the boosters to detach. how does the booster/glider work with a nose cone hanging from it? But what if you configure the boosters with added wings that make it fly tail first? Would the glider work better trailing a nose cone? Or do you just eject the nose cone (with a streamer) and it's not attached at all?

 

[ReynoldsSlumber]

Problem with using the Apogee strap on booster mechanism is that the nose cones have to separate to allow the boosters to detach. how does the booster/glider work with a nose cone hanging from it?

Could make it so that the nose cone slides forward a set distance and then hits a stop.
Could even vent the ejection exhaust toward the center stage, for extra push-off force. So long as it can take the heat, as it were.

 

[jqavins]

Problem with using the Apogee strap on booster mechanism is that the nose cones have to separate to allow the boosters to detach. how does the booster/glider work with a nose cone hanging from it? But what if you configure the boosters with added wings that make it fly tail first? Would the glider work better trailing a nose cone? Or do you just eject the nose cone (with a streamer) and it's not attached at all?

Could make it so that the nose cone slides forward a set distance and then hits a stop.
Could even vent the ejection exhaust toward the center stage, for extra push-off force. So long as it can take the heat, as it were.

I was thinking of two options there. First, there are other methods than Apogee's.

Second, I was thinking along the same line as @ReynoldsSlumber, and mulling over how best to do that. I'm leaning toward a slot or two in the nose cone shoulder and matching pins attached to the body tube, so the nose cone can move forward only the length of the slot(s).

 

[Capt. Eric]

Second, I was thinking along the same line as @ReynoldsSlumber, and mulling over how best to do that. I'm leaning toward a slot or two in the nose cone shoulder and matching pins attached to the body tube, so the nose cone can move forward only the length of the slot(s).

But then you have a nose cone on the glider that can wiggle, perhaps even move in and out, affecting the trim. Could that be a problem? I honestly don't know. Probably better than trailing a loose nose cone though.

Could the ejection be used to push the nose cone up, and spin it on the pins so it locks into place? Slot the cone shoulder to do that at the end of travel.

 

[sr205347d]

If you use drag separation, there should be no moving parts. Just make sure the core motor burns longer than the boosters.

 

[David_Stack]

How about a pylon on the main airframe with a 'locating pin' extending aft? The nose cone of the glider (balsa) has a hole drilled all the way through it, and the glider also has a ventral fin at the back with a protrusion/hook to engage against the bottom of the main airframe tube.

Thrust from the booster/glider is applied to the main airframe through the locating pin and the ventral fin, and then at booster motor ejection the ejection charge through the nose cone passage pushes the booster/glider aft off the pin.

Yes, the glider aero would be less than optimum with the hole in the nose cone, but I can't imagine the L/D for that 'craft' will be all that high anyway...

 

[ReynoldsSlumber]

ISecond, I was thinking along the same line as @ReynoldsSlumber, and mulling over how best to do that. I'm leaning toward a slot or two in the nose cone shoulder and matching pins attached to the body tube, so the nose cone can move forward only the length of the slot(s).

Encourage designing a creative mechanism like that! Suggest that given the high accelerations involved, and also keeping in mind building light, it might be good to have a piston-like mechanism that hits a stop that goes around the circumference of the interior of the tube, thus distributing the stopping force around a circle. Could also cushion the stop with rubber or foam, to take it from like a thousand g's (something to be reckoned with, even with a light balsa nose cone) to a couple hundred.

 

[jqavins]

Also something I've thought about. I'd rather have something I can take apart for repair or maintenance, which would be problematic with that ring. But nothing is off the table.

 

[boatgeek]

I'd manage release with a burn thread cut by the side booster ejection charge. The thread is led through the body tube (punch holes just forward of the mmt) and then forward to a "hitching post" on the booster. The pods are primarily retained by thrust--if the burn thread isn't installed, they slide right off.

A couple of other interferences to consider:
I don't have a good sense of how big the pod wings need to be to make them glide. If they're so big that they'd interfere with the booster fins, then maybe give the booster two T-fins like Hotblack just posted in the half baked designs thread.

You don't want the pod gliders to fall directly under the booster so they don't get toasted by the flame. Either make the booster fairly large diameter or add a little catch at the aft end that will encourage the pod nose to fall away first

Any way you shake it, I'd plan to light BP motors with ematches for reliably simultaneous ignition.