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rockets

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I recently bought a Estes Mammoth. After looking at the rocket, I decided to try me first Dual-Deploy rocket. I am using the 4 inch long coupler as the E-Bay. I even cut out a 3 inch long piece of 1/8 inch plywood for the electronics to go on. My dad owns a scroll saw, so my older brother can easily make 2 bulkheads. I'm going to go to the hardware store, hopefully soon to pick up 2 eyebolts. But, I really,really feel like I'm leaving a component out. I know I can't glue both bulkheads into the coupler because how do you get to your electronics?
And one last question, how big is the Eggtimer flight computer?

Thanks,
 

Bat-mite

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A piece of threaded rod thru the bulkheads, with a nylon insert nut on one side and a wing nut on the other. Use a straw or piece of brass tubing epoxied to the sled to slide the sled up the rod.
 

Nytrunner

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+1 on the threaded rod.

Kudos for looking at the challenge of doing dual deployment. You'll be setting yourself up for Vmax, Warp9 and long burns later on.

A word though, you'll need your parents or club mentor to handle the blackpowder (legally that is). You can do all the research, calculate your charge size, and plan how it's set up, but when it comes to measuring the powder and packing the wells, someone older needs to be the handler.

Keep it up!
 

rockets

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Why do you put small pieces of PVC on each bulkhead? Do they connect to the electronics? I went to Home Depot tonight and bought all of the parts that Bat-Mite told me to get.
Thanks,
 

blackjack2564

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On a rocket this size, use # 6 or 8 threaded rod to keep the weight down. A kevlar loop pulled through the center hole, where an eyebolt would normally live, will save more weight and be plenty strong point of attachment for recovery gear.
 

MaxQ

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Why do you put small pieces of PVC on each bulkhead? Do they connect to the electronics? I went to Home Depot tonight and bought all of the parts that Bat-Mite told me to get.
Thanks,
"small pieces of PVC on each bulkhead?"

Are you referring to the ejection charge wells ?
Some people use short lengths of PVC fore and aft on the bulkheads to house BP ejection charges for drogue deployment at apogee and main deployment at the preset altitude...
And yes, they would connect to the electronics.
Looking for a picture to illustrate the point....found this on "Big Rockets" website:



You'll need to start thinking about a method to attach the forward part of the rocket airframe to the coupler/electronics bay for retention...and venting the bay, if barometrics are involved.
Jim makes a good point on the thread size and loop... as this is a smaller size rocket.

The 60 "+/- airframe length you have does afford some room to make it a dual deploy.
There are probably as many ways to do this as there are people in the hobby...unlike the picture here...on larger projects I like to have a washer where the eyebolts are placed on the fore and aft bulkhead as these are the load bearing points of the recovery system.

Does your brother do rocketry?
 
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KenRico

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On a rocket this size, use # 6 or 8 threaded rod to keep the weight down. A kevlar loop pulled through the center hole, where an eyebolt would normally live, will save more weight and be plenty strong point of attachment for recovery gear.
+1 on the kevlar loops.

Kenny
 
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Igotnothing

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I didn't look up the diameter of the Mammoth, but unless it is small (38mm?) a 4" coupler may not engage enough of the body tubes to keep the rocket straight and stable. Flexing at the middle is bad.
I think the recommended engagement into each tube is 1 caliber. So for a 3" diameter rocket, with a 1" vent band for the barometer holes and a switch is 3+1+3=7" coupler.

The Eggtimer Quark's small components will not pose a challenge to your young fingers and eyes, but the skills to solder well will. However, if you know someone who can inspect your setup before you begin, and to guide you through the first couple of components, by the time u finish you will be years ahead of your peers.

Go for it. Even if it doesn't work you will never regret learning to solder.
 
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grouch

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These kinds of questions are best left for your mentor who is going to help you fly the rocket anyway. A lot can be lost in translation on a forum and some bad things can happen if not done properly. Slow your roll young Jedi and enjoy the journey. Dual deploy and minimum diameters aren't going away anytime soon.
 

MaxQ

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I didn't look up the diameter of the Mammoth, but unless it is small (38mm?) a 4" coupler may not engage enough of the body tubes to keep the rocket straight and stable. Flexing at the middle is bad.
I think the recommended engagement into each tube is 1 caliber. So for a 3" diameter rocket, with a 1" vent band for the barometer holes and a switch is 3+1+3=7" coupler.
It's 2 " diam. according to what I saw online. I have Loc Vulcanite with a lot of mileage on it...it had a 5.5 " long Av. Bay with a GWiz and I shot it with some fast burning Aerotech H blue motors.
That said, I had fiberglassed it and the wall thicknesses of the coupler was pretty hefty. I used the old Stu Barret internal twist and lock method using threaded couplers on a single projecting threaded rod.
So, good point....this is an Estes rocket so it may be lighter weight materials.


These kinds of questions are best left for your mentor who is going to help you fly the rocket anyway. A lot can be lost in translation on a forum and some bad things can happen if not done properly. Slow your roll young Jedi and enjoy the journey. Dual deploy and minimum diameters aren't going away anytime soon.
I was curious myself, if Andrew has an older brother that was going to be signing for his flights, I think he would be answering basic questions like this.
If his brother cannot - because he hasn't advanced this far in the hobby, then I have to wonder what is motivating Andrew to exceed his older brother's experience level...or have I missed something?
 
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rharshberger

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I was curious myself, if Andrew has an older brother that was going to be signing for his flights, I think he would be answering basic questions like this.
If his brother cannot - because he hasn't advanced this far in the hobby, then I have to wonder what is motivating Andrew to exceed his older brother's experience level...or have I missed something?
If that scenario is the case then both need to read Modern High Power Rocketry 2.
 
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MaxQ

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Andrew:

You are a Tripoli member and if I recall correctly you are enrolled, or in the process of enrolling, in the TRM program. Excellent.

Do you have a mentor (your older brother that you mentioned) or another person at the club you launch at?

I'm only asking, because some of what you are asking here online would be the kind of things your mentor in the TRM program would be helping you with and eventually flying with you as mentor at the launches you attend.
Not that we mind giving advice here of course.

Dual Deployment is one of those significant steps along the way, your onsite launch mentor will be handling the BP tasks as was mentioned by Nytrunner in his post - and the mentor may want to weigh in as you work your way through the program.
 

rockets

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Andrew:

You are a Tripoli member and if I recall correctly you are enrolled, or in the process of enrolling, in the TRM program. Excellent.

Do you have a mentor (your older brother that you mentioned) or another person at the club you launch at?

I'm only asking, because some of what you are asking here online would be the kind of things your mentor in the TRM program would be helping you with and eventually flying with you as mentor at the launches you attend.
Not that we mind giving advice here of course.

Dual Deployment is one of those significant steps along the way, your onsite launch mentor will be handling the BP tasks as was mentioned by Nytrunner in his post - and the mentor may want to weigh in as you work your way through the program.
I have an older brother who is an L2. I will try the TMP test as soon as I get a chance, I could do it a lot sooner if I did it online!
Thanks,
 

Bat-mite

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I have an older brother who is an L2. I will try the TMP test as soon as I get a chance, I could do it a lot sooner if I did it online!
Thanks,
How would the TAP or prefect witness it if you did it online?
 

ksaves2

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13 years old guys.
Missed the above where Andrew stated his older brother is L2 already. Has his signatory "in-house" although perhaps the older brother might not have has much experience
with DD. In that case, I can understand Andrew's need for questioning or perhaps he wishes to get other opinions on how to do the task. Nothing wrong with that.

Kurt
 

grouch

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Didn't miss it at all. If his mentor does not have much experience with DD then how can he be a mentor. My pointing out his age is to remind people here that he is not going to "get it" for quite some time as illustrated by his wanting to take the test online.
 

dhbarr

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Didn't miss it at all. If his mentor does not have much experience with DD then how can he be a mentor. My pointing out his age is to remind people here that he is not going to "get it" for quite some time as illustrated by his wanting to take the test online.
Offering a different perspective: many if not most of the tests persons of this age group have taken may be all online with only an enforcement proctor. This can be a parent, guardian, teacher, or webcam + screenwatcher.

Expressed differently, many tests are given online these days; paper tests & scantrons are headed the way of the punchcard and ditto.
 

ksaves2

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Offering a different perspective: many if not most of the tests persons of this age group have taken may be all online with only an enforcement proctor. This can be a parent, guardian, teacher, or webcam + screenwatcher.

Expressed differently, many tests are given online these days; paper tests & scantrons are headed the way of the punchcard and ditto.
Yeah but in reality it's not practical for a small organization to do online testing. Cheating would abound. Kurt
 

Handeman

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Yeah but in reality it's not practical for a small organization to do online testing. Cheating would abound. Kurt
I tend to agree, but I'm old! I think even small organizations need to find ways to get onboard with how the world works for younger people that have grown up "online". I'm sure one of those young'en will figure out a way to do it. If we don't, we'll fade into the past with everything else that isn't "modern"
 

MaxQ

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I tend to agree, but I'm old! I think even small organizations need to find ways to get onboard with how the world works for younger people that have grown up "online". I'm sure one of those young'en will figure out a way to do it. If we don't, we'll fade into the past with everything else that isn't "modern"
Well, just out of curiosity - I checked what the test procedure is like.
Here is what is on the website:



TMP Training:
Tripoli Mentoring Program Training trains Juniors in safe rocket construction and safe range practices. Successful completion of the TMP Training grants the Junior flyer access to restricted high power areas.

TMP Training is a self-study program that can be done either by the Junior alone or, preferably, under the guidance and advice of a Mentor. The training culminates in the taking of the TMP Training Exam. The exam is 30 questions long, with 15 Technical questions and 15 Safety questions. The Technical questions cover knowledge of safe rocket construction and launching. The Safety questions cover range safety knowledge. A passing grade is 83% correct, meaning that a test taker can miss no more than 5 questions to receive a pass.

The TMP exam can be administered by Prefects, TAPS, TRA Directors, and can be taken at the launch site. The Junior flyer may join Tripoli, take the TMP Training exam and fly under the TMP all on the same day. The exam has two versions. If the first version is failed, the Junior may immediately take the alternate version. If both versions are failed, the Junior cannot take the exam again for a minimum of 7 days.

Before completing the training, the Junior member must obtain written consent from a parent or legal guardian for the participation in high power rocketry activities. The consent statement is on the TMP Training Exam answer form, and must be signed before taking the Exam.

After completing TMP Training, the Exam Administrator will send a copy of the exam to Tripoli headquarters. The Junior will receive a new membership card that reflects the completion of TMP Training.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


I don't think you can take the Level 2 exam online, so this appears to be no different.

Maybe that will change in time.

In the interim, Andrew should get that mentor lined up and stay in close contact with his club...

I was going to make a few suggestions here that we could do with that Estes Mammoth DD project, but I'm thinking I wouldn't want to overstep his mentor.
 
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Zeus-cat

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If you run into problems you can always bring your rocket to eRockets on a Tuesday night. I know you said that was difficult for you to get up there as you said are in Cincinnati in the other thread, but we help people with this kind of stuff ALL the time. As someone else said, kinda tough to talk someone through this on this here internet thingee.
 
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