Low power dual deploy.

[apburner]

Well I have decided I need a low power rocket I can use to practice with dual deploy So I am building one. Gonna be BT50 with an 18mm motor mount. 3 or 4 fins. Will use 2 BT50 couplers with a 3 inch ring to tie them together. Still not set in stone but I will play with the sims on openrocket when I get a chance next time I am off work. Looking for maybe 1000ft on a D21 and able to fly high enough for dual deploy on a C6. We shall see. Oh ya I will be using a quark. Once that is built and flown a few times I may turn my Sun-ward Arachnid into a dual deploy by adding a coupler and length of tubing and use it to learn my other altimeters. I am doing all this so I can just fly locally and not have to drive 2 hours to a field when there is a launch on a weekend I am not working on. I work every other week end so that is rather inconvenient.

 

[Bat-mite]

Good luck, and most of all ... have fun!

 

[watermelonman]

I built my Leviathan for dual deployment. It was great fun. The one problem that made flights problematic and made me stop trying dual deployment with low power materials was deploying one compartment while keeping the other constrained. Using shear pins with this sort of material is not great, even though I reinforced the holes, first with CA then small brass plates. The body tube simply cannot keep up. The other solution was to balance the charge size against friction fitment of couplers. I could make it work but it was never as reliable as I would have liked.

If I did another one it would be with a cutter or chute release of some form.

 

[wjmoser]

Apogee sells various sizes of e-bays. I bought a BT-55 and there was plenty of room for a LiPo and an Eggtimer Quark. I modified an Estes Extreme 12, but haven't had a chance to fly it yet. It ended up far too heavy to fly two stage BP motors, but should be ok for some single stage BP motors. Watch your thrust to weight ratio and try to keep as light as possible. There's not really room for charge wells, but the e-bay instructions suggest disposable glove finger tips. Unfortunately they don't have a BT-50 size. Here's the link:

https://www.apogeerockets.com/Electronics_Payloads/Electronic_Bays

 

[Tonimus]

DD on low power tubes is tough, as others have said. I got by with #2 nylon screws, but if I was going to do it again, I'd use a Jolly Logic chute release.

 

[MALBAR 70]

+1 for the JL chute release, one of the best investments I've ever made.

 

[ksaves2]

DD on low power tubes is tough, as others have said. I got by with #2 nylon screws, but if I was going to do it again, I'd use a Jolly Logic chute release.

Ditto that. Things get cramped in small rockets and space is tight. Making a robust ebay one can get into can be a challenge for the electronics. Twist and tape can be used to switch on the electronics but would want to
tape the wires carefully 'cause if you blindly stuff the wires into the ebay and there is bare copper sticking out, if it shorts a trace on the board of your deployment device, could ruin your day.

2.5" or 2.76" diameter is easier to work with and with cardboard could get some serviceable flights with G motors. I'm talking about lofting a deployment altimeter here and not a JLCR. If the OP wants to experience standard DD with ematches, BP etc. then I think a rocket of modest length at those diameters would be more easily workable.

One caution is to use charge cups on the bulkheads for the deployment charges or put a long screw on the bulkhead and ziptie the microcentrifuge canister charge holder to the screw. Free ematch canisters in cardboard rockets can blow out the sides of the tube! I know 'cause I've did it twice in the past!:lol::bangpan: Kurt

 

[apburner]

Lots to work out. Are there any sellers of 24mm fiberglass tubing and couplers. Fiberglass would fix a lot of the issues brought up in this thread

 

[Tinker]

May I suggest a dual deploy using motor triggered aft ejection and then electronic based front ejection? No high stress on an ebay, no shear pins.

I have some designs that may help, but they are untested. Proto-type should be finished tomorrow, but test flight won't be until the 15th of Oct in Pueblo. It isn't dual deploy, but it would be trivial to add.

Tinker

 

[KenRico]

I used a Wildman Vindicator DD for my first dual deploy flights.. it is indestructible. .. but had to make the drive.

You can launch a 2.6 inch rocket like the Super DX on F and G motors.. or clone something similiar.

Quark will fit any PSII rockets .. and they are on clearance now .

I like fg lids so paper rocket would need to have a blue tube coupler or internal fg wrap, also would still use kevlar bridle and adapt for buttons and shear pins .

Kenny

 

[sl98]

I do a lot of DD using BT55 and BT60 airframes and a Quark. I went this route because it is a great way to learn and hone your DD skills. It is also inexpensive and I can fly on a much smaller local field.

I have several scratch builds as well as converted Estes kits like the Monarch that I fly DD. Keeping weight down and not overbuilding is the key. I've made all my AV bays using 3/32 basswood sleds and 4-40 threaded rod with nylon wing nuts. I use either a kevlar loop or a very small/light weight picture frame size screw eye as the attachment point on the bulkheads. I use plastic caps from AT BP charges as my "charge well" and 2 very small removable plastic rivets to hold the payload bay to the AV bay.

I've have not had much success with 18mm reloads because of weight issues. My experience is that you need a 24/40 E or F reload. Depending on the rocket, I can fly DD with apogee from 1000 - 3000+ ft using 24mm AT reloads. I haven't had any issues with durability of the body tubes.

You can see a couple pictures of one of my BT55 AVbay and Quark here:

https://www.rocketryforum.com/showt...u-like-the-best-and-why&p=1589880#post1589880

and a plastic cap charge well here:

https://www.rocketryforum.com/showthread.php?131713-Charge-Well-Design&p=1544402#post1544402