Dual Deploy Rocket Questions

[Bruiser]

I have been thinking about dual deploy and as I like scale models I was thinking an Aerotech Astrobee-D might be a good rocket to start with but when I went to order it they are out of stock. They do have the Aerotech Arreauxbee-Hi though and I have been thinking about it. I'm just not sure there is enough room in it for the two bays. Here is a snip from the sim. It shows the bays are only about 8 inches long, not including eyebolts, charge cannisters, etc.



Will those bays be large enough or should I wait for the taller Astrobee-D to come back in stock? The bays on that rocket should be about 15 inches long. Would the longer bays give me a better chance of success?

Thanks,
-Bob

 

[David_Stack]

How large are the chutes (particularly the main) you've modeled to arrive at a safe descent rate? That is largely going to dictate how much body tube volume you need...

If you have that main chute on hand, I'd pack/bundle it up in any blanket, etc. you envision using, and then measure.

As a data point: my Partizon set up for dual deploy flies with a 36" Public Missiles Dura Chute. Upper payload body tube is 15.5". I lose 3" due to the Avionics bay (not counting the charge well which is about 1.25" long). I did cut the bottom off the nose cone and inset a ply bulkhead up inside the cone. Recovery harness is kevlar, probably 15' worth. I can get it all packed in there without undo 'stuffing'/forcing.

 

[Bruiser]

I have not figured out how to OR a dual deploy rocket yet. This is the first one. I think I saw a YouTube video about just that so I'll need to watch it.

The kit comes with a 30" and a 22" parachute so maybe those sizes? Might have to go to a 36" for the main but we'll see.

You did bring up a valid point about the nose cone. This is not my sim so take this with a grain of salt but the shoulder on the nosecone seems to be about 2 1/2 inches. I do alway cut off the plastic loop and epoxy in a bulkhead. I could recess the bulkhead and gain some room that way.

Also, I know the motor tube is 12 inches long. I could easily trim it back to say, 10 inches and gain a few inches there. My 29-180 case is only 7 5/8 inches long and my 29-40/120 is even shorter...

-Bob

 

[Titan II]

I do alway cut off the plastic loop and epoxy in a bulkhead. I could recess the bulkhead and gain some room that way.

Forget the bulkhead and just epoxy a length of shock cord inside the NC.

 

[Art Upton]

I hate to add this different option for that rocket. After making more dual deploy rockets that I can shake a stik at... I now prefer the Chute Release method. There are many but I chose the Jolly Logic version of a chute release.

I was finally convinced, being the LCO of the NASA student launch for many years when I saw the collage teams even using them on large rockets.

Since then I use the chute release. On some rockets that use a motor with no motor ejection, I use the AV-bay to provide the apogee charge and the main in the booster wrapped with the chute release.

This de-complicates things for me.

Not everyone will like this method, but I switched to it. Even flew my Caliber ISP on the I65 with the main on JLCR, altimeter for the apogee charge since the motor is plugged.

Edit: The JLCR makes flying a rocket like the LOC I-Roc a breeze

 

[Wrightme43]

You might look at @DragonRocketry the 29mm TailSpike is designed for dual deploy, it includes the av bay. I just bought one and it is a very sweet kit.
Scott makes wonderful kits, this is my 4th kit from his store. Every one has been outstanding.

 

[Titan II]

You may want to look into either of these. MC models are first class kits. I have built the 150A.

https://www.madcowrocketry.com/3-aerobee-150a/

https://www.madcowrocketry.com/3-aerobee-hi/

 

[Bruiser]

Art, I have a JLCR that I used regularly. The dual deploy thing is a stepping stone for possible future two stage rockets.

Wrightman, the 29mm TailSpike is a smaller diameter rocket than I really want. Not really looking to go super high. I'm just looking to learn the electronics

Titan II, I did see those rockets. I was looking for something in the 2.2 to 3 inch range and I wanted to stick with 29mm. Both of those rockets are 38mm.

I went ahead and pulled the trigger on the Areauxbee-Hi. I couldn't pass up the deal and I'm super excited to give this a go. Once I get the kit in and verify everything I'm sure I'll be back with potential ideas

Thanks,
-Bob

 

[soupmanrmc]

I converted a LOC #780 to dual deploy. Used the 3" AV Bay Lite. Sled holds a Missileworks RRC3+, w/ 9v battery. Weighs in at 1409g with G64 and G76 motor (29/40-120). I flown her twice as the fields are unwaivered. Altitude about 600ft. Drogue 22" LOC; main 36". Recommend main at 300ft.

 

[bjphoenix]

I have not figured out how to OR a dual deploy rocket

It might help to find an OR file for a commercial kit with dual deploy and see how it is set up.

 

[Wrightme43]

Good luck, and the Areauxbee sounds fun too! I hope you have a blast with it.

I practiced D.D. with the loc deployer. It worked great.

The RRC2 and the Blue Raven are the only two altimeter I have tried. Very satisfied with both of them.

The raven's safety features are very impressive. (90 degree of launch angle it fires deployment, or if descent speed exceeds preset it fires deployment.)

Land Shark and Ballistic return, mitigation built in sounded very good to me.

 

[David Schwantz]

Neither rocket you cited need a large chute. Top flight recovery makes great thin mil chutes. also you can do things like omit the eyebolts and just use loops of Kevlar instead.

 

[Wrightme43]

I converted a LOC #780 to dual deploy. Used the 3" AV Bay Lite. Sled holds a Missileworks RRC3+, w/ 9v battery. Weighs in at 1409g with G64 and G76 motor (29/40-120). I flown her twice as the fields are unwaivered. Altitude about 600ft. Drogue 22" LOC; main 36". Recommend main at 300ft.

This may be wrong but what I do is select the drouge parachute or streamer to deploy at apogee in the settings on the part.

Then click the select altitude box to deploy the main parachute at 600' above ground level.

It is pretty accurate compared to reality measured descent under drouge and main recorded on the raven.

Also I have noticed that deployment ejection G exceeds launch and landing G.

 

[soupmanrmc]

The first flight at default ( dropped at apogee, main at 500) ejected both, as the alt was about 570. Main was wrap up in cord, acting like a giant streamer. The 2nd launch hit 630. Adjusting the main deploy lower allowed everything to get out of the way and chute fully open.

 

[Titan II]

also you can do things like omit the eyebolts and just use loops of Kevlar instead.

+1


You can also dispense of the charge cannisters and use glove finger, or similar, charges.

 

[soupmanrmc]

+1
View attachment 674880

You can also dispense of the charge cannisters and use glove finger, or similar, charges.

The thought occured, but I am apprehensive about zippered tubes. Definitely will work!

 

[Titan II]

The thought occured, but I am apprehensive about zippered tubes. Definitely will work!

How do either of these techniques have anything to do with zippered tubes?

 

[soupmanrmc]

How do either of these techniques have anything to do with zippered tubes?

I see what what was being said, after looking at the pic. Good idea.

 

[bad_idea]

I have not figured out how to OR a dual deploy rocket yet.

Check the examples under File -> Open Example.

Neither rocket you cited need a large chute. Top flight recovery makes great thin mil chutes. also you can do things like omit the eyebolts and just use loops of Kevlar instead.

Was going to say the same things. Top Flight thin mils pack shockingly small.

 

[Bruiser]

The kit comes with a 30" and a 22" parachute so maybe those sizes

I just realized this is not correct. Those are the size chutes for the Astrobee-D. The Areauxbee-Hi only comes with one chute, i believe a 30 inch one

I did watch the YouTube video on OR dual deploy but haven't played with the sim again quite yet. I am waiting to verify all the parts in the kit. Also kicking around the thought of a little kit-bashing

Bob