First Dual deploy rocket

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Looks good. Under the category of personal preferences...I would make the fins a bit bigger. Under the category of practicality, I think your motor mount tube is a bit long. You are going to have a tough time stuffing everything in there the way it is. I'd make it a bit longer than the root chord of your fins. I would also switch out that 29mm with a 38mm mount. There are oodles of cool G motors like the one you have in there by all the major HPR manufacturers in 38mm size.

Otherwise - looks good!

-Dave
 
No unless you are talking about the Quest Q2 ignitors. Those work great. Most ignitors need way too much current for a 9v to lite them.

By the way, you don't have to change the fin shape/size on my account. That was just a personal preference thingy. :wink:

-Dave
 
DAllen said:
Looks good. Under the category of personal preferences...I would make the fins a bit bigger. Under the category of practicality, I think your motor mount tube is a bit long. You are going to have a tough time stuffing everything in there the way it is. I'd make it a bit longer than the root chord of your fins. I would also switch out that 29mm with a 38mm mount. There are oodles of cool G motors like the one you have in there by all the major HPR manufacturers in 38mm size.

Otherwise - looks good!

-Dave
Click to expand...

One thing to keep in mind is that all Aerotech 38mm reloads, including G's, incur the hazmat fee. But most 29mm, even 29/360 reloads, do not. You can get up to an H268 or I200 29mm reload without hazmat. It has to do with the weight of the propellant grains.
 
yea,

Im going to stick with the 29mm motor mount. Where do you guys get terminal blocks? Are quest q2 the most popular ignitors? What are some other choices for ignitors? Im only going to fly this rocket on g's because i do not have a level one cert.

Attached is the updated file.

Thanks for all the help!

View attachment First Dual Deploy rocket.ork
 
Just keep in mind that you can always adapt down easily, but tearing out a 29mm MMT to put a 38 in it would be a heck of a lot more work. Nobody says that because you have a 38mm MMT you need to put a 38mm motor in it. Heck I put a 24mm F32 in my minimum diameter miriah 38. It was quite a macgyver-esk rig, but it worked :D
 
They have terminal blocks at Radio Shack and at Aerocon. I'm with you, I tend to stick with 29mm motor mounts in MP rockets. I can't see a reason to put a 38mm mount in a rocket that I'd never put more than an H in. It's been recommended to me many times to put a 38mm mount in my various scratch builds, and I understand that you can't adapt up. But adding an adapter does add some weight, and slightly complicates retention. I have 29/40-120, 29/120, 29/180, and 29/240 cases, which allow me to use reloads from E's to H's. I think that's plenty of choice.
 
I just looked at your Open Rocket plan again, and I don't see any reason whatsoever to put a 38mm motor mount in it. Especially since you don't have your level 1. There are 38mm G's, but like I said before, you have to pay the $25 hazmat fee to order them. With a 2.24" rocket, you'll have plenty of choices with a 29mm mount. There are only two 38mm G's, but there are at least five 29mm G's. And if you're using single use motors, there are no 38mm G's, but there are several 29mm G's.
 
qquake2k said:
They have terminal blocks at Radio Shack and at Aerocon.
Click to expand...

I can't tell from the pictures if the Euro-style terminal blocks have screw holes for attaching the strip to the plywood. Gotta pick up a two-circuit block for my Super-Duper Neon 29. Size may be an issue as well. 38mm tubing is fairly small.

EDIT: Never mind. The picture at Aerocon clearly shows how they attach. My bad.
 
o1d_dude said:
I can't tell from the pictures if the Euro-style terminal blocks have screw holes for attaching the strip to the plywood. Gotta pick up a two-circuit block for my Super-Duper Neon 29. Size may be an issue as well. 38mm tubing is fairly small.

EDIT: Never mind. The picture at Aerocon clearly shows how they attach. My bad.
Click to expand...

Radio Shack has two sizes. The mini might work in 38mm tubing. Both can be cut into pairs, and there are holes in the center that you can put a screw through.

https://www.radioshack.com/product/index.jsp?productId=2103986

https://www.radioshack.com/product/index.jsp?productId=2103231
 
yzf450motoxrider said:
Im going to stick with the 29mm motor mount.
Click to expand...

I would strongly recommend the 38mm MMT. I don't use open rocket so I can't look at your design, but from what has been said, I'm assuming a 2.24 diameter with dual deployment.

My first dual deploy rocket was my L1 that was build with thick wall mailing tubes. 2" ID and 2.25" OD. It was probably heavier then what yours will be, about 3 lbs 12 oz without the motor. I found I flew it on 38mm I motors much more then I ever did on 29mm or 38mm H motors. The reason was the dual deployment. With DD, going 3,000 - 4,000 ft on I motors wasn't much different then 1,000 - 1,500 ft with a motor deploy rocket. I even flew it on a J350 once, just because I could.

I know you intend to fly this as a MPR on G motors, but it's your first DD rocket. You'll find you can fly it much higher then you do your MPRs and you'll probably find yourself looking for a L1 cert, just to be able to fly the rocket to the higher altitude you can work with when using DD. I would recommend you don't restrict how you can fly DD because of what you are currently flying with motor ejection by using a 29mm MMT when a 38mm MMT can be used.
 
I’m ok with the 29mm motor mount on an I200 its simulated altitude is 4650. That plenty high enough for me. The basic goal of this rocket is for me to gain experience on a dual deploy rocket that is cheap to fly and won’t cost much if it crashes.
 
yzf450motoxrider said:
I’m ok with the 29mm motor mount on an I200 its simulated altitude is 4650. That plenty high enough for me. The basic goal of this rocket is for me to gain experience on a dual deploy rocket that is cheap to fly and won’t cost much if it crashes.
Click to expand...

I would agree, but I still think you will wish you had built it with a 38mm at some point, even if all of your first flights use a 38-29mm adapter.

Between Aerotech and Pro29 there are only 4 I reloads available in 29mm and you can't get the WARP 9 Aerotech loads in 29mm.

Once you start flying DD, you'll quickly find that 4,650 isn't all that high on a day with calm or light winds and you'll begin to want to hit the one mile level at some point (it just keeps calling louder as you get closer). A 38mm will get you there.

Of course you can stick with the 29mm and just build a new 38mm when the urge hits. I can't argue with 2 rockets! :D Have fun and we want to see the build report, with LOTs of pictures!
 
qquake2k said:
29mm reloads are a bit less expensive than 38mm. Especially if you get G reloads for the 29/40-120 case from Hobbylinc.
Click to expand...
No doubt.

Just saying that worrying about the cost of a rocket itself is comical considering how many reloads we put through them. I probably spent $50 in parts building my L1 ship and have already put twice that amount in reloads through it.
 
29mm Is good that way when you are ready to fly 38mm you will have an excuse to buy and build another rocket. :D

TA
 
thobin said:
29mm Is good that way when you are ready to fly 38mm you will have an excuse to buy and build another rocket. :D

TA
Click to expand...
If you stick with the same airframe diameter, all you need is a new booster section. Use the rest of the original rocket. I do believe a whole second rocket is better though :wink:
 

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