Dual Deployment?

At what point do you start using dual deployment? What is the best way to start my first dual deployment? How much is custom built and how much is manufactured? I'm getting very curious as I get closer to using it.

Kruegon said:

At what point do you start using dual deployment? What is the best way to start my first dual deployment? How much is custom built and how much is manufactured? I'm getting very curious as I get closer to using it.

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Second attempt at responding to your query. Firefox crashed.

When your rockets go too high for simple motor deploy and the resulting retrieval hikes get old, most folks decide to look into dual deployment.

The electronics are as little $50 and most the parts are the usual modeling materials that you've probably already used. In dual deploy, you'll just need more of them.

Here's a simple alt bay that I'm planning to stuff into the nose cone of my Polecat Aerospace 5.5" Goblin. 1/8" plywood for the sled, miscellaneous wiring and hardware, a terminal strip and rotary switch to power up the altimeter. The altimeter cost less than $50.

View attachment 254925View attachment 254924

Take a look at the various build threads here on TRF. There are almost always pictures of altimeter bays.

Kruegon said:

At what point do you start using dual deployment?

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What o1l dude says! At our field, most flights over 3,000 ft are dual deployment. I don't fly rockets over 2,000 ft without it, unless the winds are unusually calm.

My first DD flight was the test flight of my L1 rocket on a G64W. It only went 464 ft. but it worked.

So I think the real answer to your question is "whenever you want to use it." That may sound a little condescending, but it isn't. There are no altitude limits, no rocket or motor size limits, etc. for when you can or should fly DD. If you want to try it, go for it!

Like Handeman, my first DD flight was under 500 feet too. I used a tall, skinny rocket on an F motor.

When you get tired of walking..LOL

The field you fly on usually would determine when to start.
Out west, with wide open treeless space they can fly M's & N's...open the main at top & just drive 3 or 4 miles to go get it.

I know of no motors L and above that have ejection charges, You must use altimeter/timer [in the rules] to deploy chute, whether you decide single or dual is still your choice.

I use one on every flight, even when it's only SUPPOSED to go 1500 or 2000 ft. That's a long walk if there are any winds up there. It can be dead calm on the ground....go up a few hundred ft and windy as heck.

Typical layered wind chart:

Note the jump of windspeed at different altitudes.



So the answer is..."it depends" on what your motivation is & where you fly.
It helps a great deal to find someone in your club to walk you through it and mentor you.

I built my first simply because I wanted to learn the technique and related tools. That particular rocket has never even been above 800 feet! One of these days, though, I will give it the nice full H it deserves.

It really depends on what you enjoy doing and what challenge you are seeking. I personally like the simplicity of motor ejection and since I added a tracker to my flying I don't get freaked out going over 3K. I like the hunt and the walk, it's good exercise. The only real downside is it does limit how much flying I do and how much I get to watch of others. Still I have really been enjoying flying this way.

grouch said:

I like the hunt and the walk, it's good exercise. The only real downside is it does limit how much flying I do and how much I get to watch of others. Still I have really been enjoying flying this way.

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I understand where you're coming from. Some of the best "after flying" stories are about recovery treks. We have a club owned Walston and I seldom fly without it, even with DD. The first time you don't, you'll need it. I enjoy the challenge and thrill when DF works the way it should! I find that the DF is seldom required to find a rocket in our area, but using it usually cuts down on the time it takes to locate the rocket. In those cases it gets you back to flying and watching other a little quicker.
I

At our field, going above about 2k without DD gets a bit risky. We have trees in the direction the wind usually blows, and inhabited area in the other directions. My general rule is becoming if it can fit, and it's going above 2k, use it! I've flown to 2100 or 2200 where we are with no DD and had it land not particularly far, and I've flown to 800 and had it land quite a ways away. With DD, save one flight, recovery has always been incredibly close. Also, it's kinda fun and cool to have the rocket "do" something once it's up there other than just drift. each field is different, and that's what really determines when you NEED DD. Talking to people at your club will help you get advice specific to your field. As for the best way to start, the RRC2+ is as simple as it gets, and I've had good success with mine. Add a 9 volt battery, 4" Madcow rocket with AV-bay, and you're good to go for a pretty easy DD setup. Doghouse Rocketry carries great charge wells, terminal strips, and wire connectors. That altimeter can fit in 29mm tubes, but 54mm and below gets a bit tricky, especially for a first time. Alternatively, a Missileworks 3D-printed sled is a great way to get started with DD at any size from 29mm up to 4" without designing your own sled. It varies widely as far as manufactured or homemade components go. You can make your own bulkplates out of wood with an adjustable hole saw and drill press, and wood altimeter sleds can be made fairly easily with a band saw or similar. you can use copper pipe end caps for charge holders, and just wire an ematch directly to the altimeter if you so desire. add some misc. hardware, and you've got a completely homebrew av-bay. Or, you could buy one of the aforementioned 3D printed sleds, buy 1 piece bulkheads and a wiring kit from doghouse rocketry, and get pretty much everything you need. I make all my bulkheads out of 1/8 or 3/16 plywood, and if it's a fiberglass rocket, I'll sometimes buy matching FG bulkplates. Forged or welded eye-bolts are ideal for recovery of most rockets, but I've never had any problems with a bent eye-bolt, and wouldn't expect any with a rocket below 20lbs or so. U bolts are even better. I love them. Nothing to unbend, twice the threaded area, and a larger surface area dispersion. I'm using 2 in tandem on my 4" Madcow Pike in the top CR. If you have the room, they're nice to use. Something else that's nice about DD is that you can use a larger main chute than you otherwise would. For instance, I would otherwise bring my Nike Smoke down on a 24" chute, but using DD I'll be able to safely use a 30" chute and get a nice soft landing.

Nate

I'd say before you jump to dual deploy, fly some with single (apogee) deploy, just to get the hang if it. Things like making sure you have a way to remember to arm the electronics, etc. Dual adds some additional possible points of failure (second chute, etc), as well as things like the proper use of sheer pins.

And as far as altitude, be careful with single or dual flying too low. Some altimeters will not fully be armed until 400', so if your sim is a bit off, and the flight is only 350', no chute! And if you do dual, you want to make sure the altitude is higher than the setting for the main charge.

Well I can't imagine using DD on less than a G. I can't imagine I own any rockets that would require it without that. My highest rocket is a PSII ascender that will hit 3k if I use the booster. But there again, that doesn't calculate APCP motors. I figured I'd want to DD my L1 cert rocket, which I plan to have ready by September. Last launch of the season is in two weeks. Not gonna bash out a L1 rocket that fast. Plus I want to design my own style. Time to beat up OpenRocket.

Kruegon said:

Well I can't imagine using DD on less than a G. I can't imagine I own any rockets that would require it without that. My highest rocket is a PSII ascender that will hit 3k if I use the booster. But there again, that doesn't calculate APCP motors. I figured I'd want to DD my L1 cert rocket, which I plan to have ready by September. Last launch of the season is in two weeks. Not gonna bash out a L1 rocket that fast. Plus I want to design my own style. Time to beat up OpenRocket.

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Sounds like a great plan to me.

That's about what I did, scratch built the L1 cert rocket with DD from heavy wall mailing tubes. I had certain goals I wanted to meet with that build. I wanted to learn more about HPR construction techniques, DD, making my own nose cones, design, etc. That all came together with that build and I probably learned more building and flying that rocket then I've learned with any rocket since. One of the things I learned is that if you really want to fly L1 motors, go with a 38mm MMT. The first six HPR flights on my L1 rocket were all I motors.

I would link to by build thread, but it's in the TRF Archive and that doesn't seem to be working.

RecoRocket said:

I'd say before you jump to dual deploy, fly some with single (apogee) deploy, just to get the hang if it. Things like making sure you have a way to remember to arm the electronics, etc. Dual adds some additional possible points of failure (second chute, etc), as well as things like the proper use of sheer pins.

And as far as altitude, be careful with single or dual flying too low. Some altimeters will not fully be armed until 400', so if your sim is a bit off, and the flight is only 350', no chute! And if you do dual, you want to make sure the altitude is higher than the setting for the main charge.

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Even with an altimeter with DD, I've always left the motor ejection charge in as insurance for an altimeter failure.....it is a freebie.
As long as you get some altitude.
Just make sure the motor ejection delay is not too short......you can select a delay to fire well after the altimeter firing the main.
I have had a save or two this way.

Handeman said:

Sounds like a great plan to me.

That's about what I did, scratch built the L1 cert rocket with DD from heavy wall mailing tubes. I would link to by build thread, but it's in the TRF Archive and that doesn't seem to be working.

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The El Jaun - Try this link......
https://www.rocketryforum.com/showthread.php?106042-El-Juan

My first dual deploy is a 29mm rocket running a E motor. Normally I wouldn't run dual deploy but in this case it's a near minimum diameter rocket punching over 3500 feet and it's barely 400mm long. I want it back, hence dual deploy.