Building a rocket with an EBAY out of Estes parts

[mtwieg]

Hey, I've recently gained access to some free estes parts through work, and I wanted to try doing a fancy scratch build with them. Something that I can test my electronics with, so it will need a removable Ebay. I'm thinking either single stage dual deployment or two stage single deployment. I want to stick with normal wood/cardboard, with a minimum of heavy hardware (I'm limited to estes motors too).

My main problem is making a locking mechanism for the Ebay without threaded screws or plastic parts. I have a few ideas, but none of them seem practical.

Any suggestions are appreciated.

-Mike

 

[Handeman]

Hey, I've recently gained access to some free estes parts through work, and I wanted to try doing a fancy scratch build with them. Something that I can test my electronics with, so it will need a removable Ebay. I'm thinking either single stage dual deployment or two stage single deployment. I want to stick with normal wood/cardboard, with a minimum of heavy hardware (I'm limited to estes motors too).

My main problem is making a locking mechanism for the Ebay without threaded screws or plastic parts. I have a few ideas, but none of them seem practical.

Any suggestions are appreciated.

-Mike

That's a tough one. By Estes motors, does that include the 24mm C, D & E or are you talking 18mm A - C
What size body tubes are you talking about? Do you have coupler tubes available too?

You might have to go with a single stage cluster to get enough thrust from the Estes.

I just finished an E bay for my L1 and used 1/4 hardware. It weighs in at 11.8 oz. I would assume you want the whole rocket (launch weight) to be less then that.

I'm using a Perfectflite HiAlt45K with 9V battery. It's a tight fit in a 1.75" ID coupler the E bay is made out of since I mounted everything on 1/4 plywood.

Different mounting scheme should make everything fit in a smaller tube.

As for closures, would #6 or #8 screws through the BT, into the end caps work? You would really need to keep the weight down and use long shock cords.

Good luck and keep us updated. Let us know what doesn't work too.

 

[jcsalem]

I've build a few BT-60 sized electronics bays. Check out these threads for details:
https://www.rocketryforum.com/showthread.php?t=18445
https://www.rocketryforum.com/showthread.php?t=37243

The first thread shows a bay that I made with just the standard Estes tubing and some bulkheads I made myself with a drill press and a circle cutter. You'll see that I use some removable plastic rivets to hold the two parts of the bay together.

Have fun!

Jim

 

[mtwieg]

That's a tough one. By Estes motors, does that include the 24mm C, D & E or are you talking 18mm A - C
What size body tubes are you talking about? Do you have coupler tubes available too?

You might have to go with a single stage cluster to get enough thrust from the Estes.

I'm pretty much set on a plugged D-12 for the first stage. Either a C or D for the second. I'd rather not have to cluster, simply because making the centering rings would be a pain, and I want to save engines. I'm not looking for high performance; I just want to test my electronics.

I can use any size body tube, but I'm thinking bt-80. I could probably make do with a 60 though.

I just finished an E bay for my L1 and used 1/4 hardware. It weighs in at 11.8 oz. I would assume you want the whole rocket (launch weight) to be less then that.

I'd like the whole thing under a pound. The electronics don't weigh much, so I don't think weight will be a problem.

I've build a few BT-60 sized electronics bays. Check out these threads for details:
https://www.rocketryforum.com/showthread.php?t=18445
https://www.rocketryforum.com/showthread.php?t=37243

The first thread shows a bay that I made with just the standard Estes tubing and some bulkheads I made myself with a drill press and a circle cutter. You'll see that I use some removable plastic rivets to hold the two parts of the bay together.

Have fun!

Jim

I was picturing in my mind the ebay being completely enclosed by the body tube, but something like that in the first thread looks good. Yours is meant for dual deployment, correct? What if I only want single deployment? Is there an easy way to fix the ebay to the bottom half of the rocket, maybe with more rivets? What type of rivets are they (I'm assuming I can find something similar from a hardware store)?

 

[uncle_vanya]

What are the electronics you are considering? Some like the PicoALT are really small. The battery probably should be an A23 (12 volt) like the Adept uses. Just make sure it works with your electronics:

https://en.wikipedia.org/wiki/A23_battery

If you are sold on wood and cardboard - why not use a bulkhead at each end of the bay and use dowels and screws to hold it all together. Another way would be to use wire to old the two ends together.

If you are doing single deployment I've seen hollowed out nosecone designs. The non-baro altimeters are better for this due to the weird pressures you can get near the nose.

 

[mtwieg]

I'm using my own homemade electronics in this rocket, so I know exactly what will and won't fit.

If I can find some of those reusable rivets, I'll do what Jim suggested. It looks solid, except I'm not clear on how ejection is supposed to happen. On deployment, does the separation occur between the ebay want the upper/lower body tubes?

-Mike

 

[zog43editor]

You can make something that will lock with Estes parts. Here's a sketch of a bayonet system that's easy to do.

I guess where the rocket's sep point is depends on what you're doing. Usually in dual deploy systems, the ebay is between the two parts of the body. The first ejection event splits the rocket at the ebay/lower section joint. The second event either pops the nose or splits at the ebay/upper section joint.

In a single deployment if you are using a motor w/o ejection (like a D11-p or an E9-p) you can split either above or below the ebay since you are controlling the ejection event. If you are using a regular motor, then I'd sep using motor ejection between the ebay and the lower section.

kj

View attachment bayonet.JPG

 

[skippy-2]

I flew a 'How High' alt this past weekend in a BT-60 bay attached to my Estes Patriot. Simple parts; a 75mm piece of BT-60, a coupler, a 75mm piece of BT-50, a BT-50 - BT-60 centering ring, balsa disc, the alt and a battery pack.

Fit the coupler to the BT-60.

Fit the centering ring to the BT-60, firm on top of the coupler.

Punch vent holes.

Seal bottom of bay with balsa disc. Epoxy to seal.

Fit BT-50 to the centering ring.

A steel leader attaches the shock cord to the alt bay, and the alt bay to the nose cone.

Three vent holes allow the pressure within the bay to equalise with the outside world. Simple to build, worked a treat.

 

[mtwieg]

Okay, I've pretty much got the thing built. It's made from bt-60 and will be capable of dual deployment and dual staging. Maybe I could make a booster that could do airstarts too.

What I did for the ebay is much like what jim did (I think). However, the electronics mounting board is glued to both end couples, and is exposed by sliding the bay body tube off of it. I couldn't find nice reusable rivets, but I did find some nylon push fasteners at home depot. These will hold the ebay body tube on and hold the upper bt (which contains the main) to the ebay. The drogue separation will be pull deployment.

Once I get my hands on a camera, I'll post some pics.

 

[fox_racing_guy]

You can get re-usable plastic rivets from most NAPA auto part stores, they are the ones I use in all of my larger E-bays.

 

[mtwieg]

You can get re-usable plastic rivets from most NAPA auto part stores, they are the ones I use in all of my larger E-bays.

What is NAPA? The only auto parts store around me is an autozone. Would that be worth checking?

Anyways, here are some pics:

https://i43.photobucket.com/albums/e360/mtwieg/IMG_1530.jpg
https://i43.photobucket.com/albums/e360/mtwieg/IMG_1518.jpg
This is the ebay, bare except for the battery in place. It will hold all three of TAG tech's devices. I'll try to get a pic later with them all mounted.

https://i43.photobucket.com/albums/e360/mtwieg/IMG_1529.jpg
This is the end of the couplers. You can see the eye screw, the terminal block, and the ejection charge holder. I'm going to be using 1/2 A motors for ejection, hence the 1/2" tube.

https://i43.photobucket.com/albums/e360/mtwieg/IMG_1531.jpg
these are all the pieces laid out. The middle bt just slides over the ebay and is held by the fasteners:
https://i43.photobucket.com/albums/e360/mtwieg/IMG_1528.jpg

https://i43.photobucket.com/albums/e360/mtwieg/IMG_1533.jpg
This is the ebay with the tube fastened on.

https://i43.photobucket.com/albums/e360/mtwieg/IMG_1536.jpg
And the pieces all fit together.

things I have to do:
launch lugs
shock cords and chute/drogue
mounting electronics
painting
make the booster stage

 

[fox_racing_guy]

Look here https://www.napaonline.com/MasterPa...escription=Plastic+Trim+Panel+Clip+/+Fastener
Then use the store locater to find a dealer near you, I know there is at least 1 NAPA dealer in Kent. Your also lucky enough to be pretty close to the "Ultimate Rocket Junk Store" known as McMaster Carr. They are right off route 43 in Streetsboro, you can order parts online then drive there and pick them up.
Now get busy making me one of those magnetic apogee detectors, I really want to try it out!

 

[mtwieg]

haha, mapquest says there's one 3 minutes from my house . I'll definitely hit it up.

The apogee detector is the first thing we're going to test. The new version blows the one that's been on our website out of the water. Much smaller (but needs an external battery), less than half the price, and much more functional.

We're supposedly updating the site soon with updated info on all three products, so stay tuned.