What are some good kits with rear ejection?

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Funkworks

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In a scratch build I'm working on, I'm considering rear ejection. I'm not sure it really matters, but this be might an opportunity for me to build a rear ejection kit in the mean time, just to see exactly how this is done in proven kits.

What are some popular or successful, current kits with rear ejection? Scale kits usually have a better chance of making it to the collection, but in this case, anything from 2" to 6" diameter could be interesting.
 
Upscale the Apogee SR-72 DarkBird. Gliders are GREAT for rear eject because the pop pod comes down separately.

The other really cool trick you can use with gliders is to put the boost phase nose weight at the forward end of the pop pod (you can even cut off the base of a hollow nose cone and extend the pop pod into the nose to get the mass as far forward as possible.). Gives you greatest CG shift gram for gram, and you unload it all from the glider at deployment and bring the mass down by chute with pop pod.
 
So in summary so far:

Estes:
  • Gyroc
  • Space Plane
  • Scissors Wing Transport
  • Bomark
  • Estes Gemini DC #2136
  • Sizzler
Apogee :
  • SR-72 DarkBird
U.S. Rockets:
  • Dual 18mm Rear Eject (Model: 07173)
I didn't think for a moment they were mostly (all?) 18 mm!
Thanks everyone.
 
Matter of opinion, but I'm not sure all those gliders really count. What I think of as rear ejection is when the parachute comes out the back but stays attached to the rocket, not just a motor pod. The US Rockets kit and the Gemini DC (and the Sizzler, I guess) are the only ones that work that way.

Here's a 14x Gemini DC upscale that did drogue rear ejection with the main out the front, looks like:

 
Matter of opinion, but I'm not sure all those gliders really count. What I think of as rear ejection is when the parachute comes out the back but stays attached to the rocket, not just a motor pod. The US Rockets kit and the Gemini DC (and the Sizzler, I guess) are the only ones that work that way.

Here's a 14x Gemini DC upscale that did drogue rear ejection with the main out the front, looks like:


I hate to pack all those chutes and rear ejection...bravo.
 
Updated List

Apogee:
  • SR-72 DarkBird
Estes:
  • Gyroc
  • Space Plane
  • Scissors Wing Transport
  • Bomark
  • Estes Gemini DC #2136
  • Sizzler (rear eject version)
North Coast Rocketry:
  • X-Wing
Sunwards
  • Pyramid
U.S. Rockets:
  • DUAL 18MM REAR EJECT Model: 07173
 
I like the close-up pic. And that would be the first nose cone rocket I’ve seen that doesn’t look silly (to me anyway).

(Love the silly mailbox but way too advanced for my current level and time constraints)

This nose cone one I’ll probably keep in mind.
 
In a scratch build I'm working on, I'm considering rear ejection. I'm not sure it really matters, but this be might an opportunity for me to build a rear ejection kit in the mean time, just to see exactly how this is done in proven kits.

What are some popular or successful, current kits with rear ejection? Scale kits usually have a better chance of making it to the collection, but in this case, anything from 2" to 6" diameter could be interesting.
Scratch build might be easier.

There is a way to “cheat” that makes rear ejection easier to load and more reliable,

The downside on rare ejection is that much of your space is filled up with the inside extended motor mount, leaving you minimal room for your recovery system. One way around this is to downsize the extension of the motor mount to all the way up to the nose. Specifically you can often go down one body tube size. You can extend the tube all the way to the nose. Cut off the base/Eyelet end of the nose, and you can extend your tube all the way into the nose (which is gonna get glued in anyway.)

Downsizing the inside tube GREATLY increased the space between tubes for recovery gear, making it easier to pack and less likely to stick.

The smaller central tube gets a bit more “charred” just in front of the engine block, a problem easily alleviated with a rolled up piece of aluminum can (yes, aluminum IS flammable, but less than regular paper tubes and the heat from ejection is short lived.)

The smaller tube is a bit weaker, doesn’t hurt to reinforce it with and extra layer of same body tube (cut lengthwise on one side, wrap around and glue) or a small adjacent carbon fiber rod or spar.

Two pluses for rear eject (in addition to preserving your fin arrangement.)

If you extend the tube all the way INTO the nose cone you can put the nose weight on the front edge of the TUBE, this makes the nose cone and body segment lighter, so less impact damage on the nose tip (which is literally the “down side” of rear eject. Putting a bit of tape on the nose tip at launch isn’t aesthetically optimal but pays dividends if it lands on rock, concrete, or asphalt.)

Also, with centering rings in front of and behind your chute, you don’t need wadding,

Good luck!
 
Scratch build might be easier...

That would be the final goal, but the idea here was to get some hands-on experience with a proven kit first, to reduces the chances of messing up the project. Not sure I trust myself otherwise. Choices choices.
 
If pop-pod gliders are being included, then Estes Skydart II should be on the list.
The downside on rare ejection is that much of your space is filled up with the inside extended motor mount, leaving you minimal room for your recovery system. One way around this is to downsize the extension of the motor mount to all the way up to the nose.
Is there any loss of reliability from needing to eject a much longer tube? I have (possibly irrational) fears of the mount getting hung up on the way out; short mount gets out quicker. Or is that simply not a likely failure mode?
 
If pop-pod gliders are being included, then Estes Skydart II should be on the list.

Is there any loss of reliability from needing to eject a much longer tube? I have (possibly irrational) fears of the mount getting hung up on the way out; short mount gets out quicker. Or is that simply not a likely failure mode?
IMO no. The gain you get from all the extra space more than makes up for longer tube.

That said, the pod needs to as loose as a nose cone would be, or maybe a better example would be low power stage coupling. You should be able to hold the rocket upright without it falling out easily, but a gentle shake or a quick upward jerk should dislodge it easily.

As I said, what I really like is the ability to put nose weight on the forward end of the tube, often actually inside the nose cone. It’s a good idea to smear some glue on the inside of the nose cone to give it a bit of protection from the ejection charges.
 
rear ejection has been in the back of mind for maybe a year now, i like the idea of no seams or breaks in the body tube.

What I was thinking of was building the motor mount with a thrust plate but inside a coupler instead of the main body tube. The assembly slides into the body tube with the thrust plate still functioning as normal. Then an ejection charge can push the coupler, motor, thrust plate, and everything right out the back.

edit: won't work with ttw fins (mine are almost all surface mount so didn't consider that)
 
Updated List:

Apogee:
  • SR-72 DarkBird
Estes:
  • Bomarc
  • Gamma (plan)
  • Gemini DC #2136
  • Gyroc
  • Scissors Wing Transport
  • Sizzler (rear eject version)
  • Skydart
  • Space Plane
Fliskits:
  • Decafeinator
North Coast Rocketry:
  • X-Wing
Sunwards
  • Pyramid
U.S. Rockets:
  • DUAL 18MM REAR EJECT Model: 07173
And since I saw it at a local-ish shop I went to recently, I got Fliskits' Decafeinator. Not having to bother with S&H is a benefit. Getting hands-on experience at a good price really was the short term goal here.
 
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I was in the same situation and went scratch build. I wanted an estes sizzler as the sacrificial kit but didn't get one.

I will say I love my rear eject rocket. Its worked everytime, and while it has seen multiple repairs, they were only due to bad design.

Make sure your motor tube is reinforced if longer than the motor. I had one get crushed by the wrapped up shock cord and had to rebuild. Added an estes motor spacing tube to reinforce the forward section.

Use wood centering rings, or double up the paper ones. Had the forward set break off after a few flights when using single estes stock ones.

Would I switch my rockets to rear eject over traditional deployment? No. But I love the different style and love the nose cone down descent. I painted mine w a bright green tube w a matching ASP green chute and its a really cool flight to watch. And il almost always get asked if its tangled or something and have to explain its rear delpoy.

Good luck and share pics!
 

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