My level two cert rocket

[edwinshap1]

I'm not creating a build thread for this one because i'm making a pretty much exact replica of this
http://www.rocketrytoday.com/octagon.html

but the BT is 32" and there's a nosecone and chute. The longest motor that i'll be able to fly is a 17" of any type.

It has a 54mm aeropack retainer, and I intend to fly it on a K540 MS from aerotech.

i need names for this rocket, any and all suggestions, but I do prefer ironic or punny names

[cbrarick]

How about the "if you don't instal active recovery I can't do my Level 2 cert for either NAR or Tripoli" rocket? Please add recovery to make it cool and certifiable

[grouch]

Or the no chute, no cert after bad Thai food rocket?

[rcktnut]

I'm not creating a build thread for this one because i'm making a pretty much exact replica of this
http://www.rocketrytoday.com/octagon.html

but the BT is 32" and there's a nosecone and chute. The longest motor that i'll be able to fly is a 17" of any type.

It has a 54mm aeropack retainer, and I intend to fly it on a K540 MS from aerotech.

i need names for this rocket, any and all suggestions, but I do prefer ironic or punny names

Looks good!!!

[cbrarick]

hehehe everyone knows you have a bad day after bad Thai food

[bandman444]

"STOP!!!" (painted like a Stop sign)

Or I like, "What time is it? CERT TIME!" (Painted like a clock)

Photos.

We want a build thread!

Bryce

[edwinshap1]

it will have a chute, but i don't know the size yet because the link on the first post doesn't have a weight, and i'm adding about 25" of body tube, a nose cone, shockcord, and the eventual chute.

i figured that since my L1 was high and fast, my L2 should be actually low and slow.


i don't want to build thread this one because it's really messy. the foam board and wood glue together make it nasty lol. i'll take some pics of the base area though to show how the spoke system works.

also, i used crazy jim's method of shock cord attachment where a piece of body tube is cut, shortened, and has a length of cord spanning the inside, which is then inserted into the body.


Bryce, loved the stop sign idea. It'll have four faces of the rocket saying STOP in black letters, with the octagon painted red

[bandman444]

BTW Jared, stop signs have white letters...

[edwinshap1]

BTW Jared, stop signs have white letters...

can you see white letters on the playa? exactly and i'm an idiot :P

[bandman444]

Because if you miss the the big red octagon you will see the black letters...

:P

Bryce

[edwinshap1]

Because if you miss the the big red octagon you will see the black letters...

:P

Bryce

maybe?

so build is progressing, i'm applying the faces to the octagon, they're looking really ugly... so much wood glue XD i'll sand it and glass it so it'll look good

[MClark]

Be prepared for the question

………. identification of the model's center of gravity and center of pressure, methods used to determine model stability, …………..

#11 at http://www.nar.org/hpcert/l2certreq.html

Mark

[edwinshap1]

Be prepared for the question

………. identification of the model's center of gravity and center of pressure, methods used to determine model stability, …………..

#11 at http://www.nar.org/hpcert/l2certreq.html

Mark

cp determined via barrowman, and ended up about 4" from base of rocket, CG just a balance test. I've spoken to art applewhite about how he determined his CP via wind tunnel testing which was about a 30 degree angle. My rocket is about the same, but the nose cone does push the cp slightly forward into the actual rocket.

i think that's adequate

[grouch]

Give the rocket a rear eject and the size of chute really wouldn't matter.

[UPscaler]

Give the rocket a rear eject and the size of chute really wouldn't matter.

+1

rear ejection would be perfect

Braden

[edwinshap1]

+1

rear ejection would be perfect

Braden

would be, but i've found that most altimeters won't arm the charges until 300+ft, which makes me uneasy, especially because it's difficult-impossible to determine the altitude properly using rocksim or OR.

[UPscaler]

would be, but i've found that most altimeters won't arm the charges until 300+ft, which makes me uneasy, especially because it's difficult-impossible to determine the altitude properly using rocksim or OR.

Motor ejection. Secure the nosecone with screws, and build a motor mount with a "centering ring block" in the top, then when the ejection charge goes off, the parachute packed above the centering ring, and the entire motor mount (anchored to the nosecone with the shock cord) will fly free! At least that's how I've thought about doing it...never actually done rear ejection, or seen how it's done



Braden

[edwinshap1]

[snip]
...never actually done rear ejection, or seen how it's done

thats why i'm so apprehensive about doing it lol. if i pack a couple grams of BP into the motor eject, it'll throw the chute far enough to catch wind without incedent

[cbrarick]

Or you could do motor ejection the way the "Cool Spool" from LOC does - you wouldn't need a big chute, you just need active recovery - like a 24 inch x form. It would make it a fairly simple prep. Just extend the motor tube far enough to accommodate the motor, and your chute wrapped in a nice piece of kevlar. use an aeropack on the other end for positive retention of the whole enchilada.

[grouch]

would be, but i've found that most altimeters won't arm the charges until 300+ft, which makes me uneasy, especially because it's difficult-impossible to determine the altitude properly using rocksim or OR.

You could use a timer to get around that problem. Just set it for the length of the motor burn and you would get an ejection on the way down regardless of altitude.

[cbrarick]

Or just use CTI and drill down the delay to the minimum

[chadrog]

If I could make a suggestion, don't do it like this!
http://youtu.be/O_5MwDjvcXY

[sodmeister]

If I could make a suggestion, don't do it like this!
http://youtu.be/O_5MwDjvcXY

That was pretty cool ,or like the guy in the backgrounds exclaims ...."alright"


Paul T

[edwinshap1]

If I could make a suggestion, don't do it like this!
http://youtu.be/O_5MwDjvcXY

yeah, the 54mm moonburners are out :P


and i'll have the delay drilled down to four seconds. It should deploy shortly after the rocket begins to aerobrake, which is nice to know :P

[edwinshap1]

The instructions call for a layer of 5oz glass, but i'm worried that i'll have a little bit of an issue wrapping the 5oz around the corner.

i'm thinking that maybe i should do two layers of 2oz glass instead to make it easier to wrap around, would that lower the strength of the wrap, or make it stronger?

[cbrarick]

Man, that was cool! Wonder how much wind & what motor. Flew mine on a K260 in 20+ at RGIX for a 150 yard walk but it burnt out about 300 feet above the ground. It just never got more then 800, sorta walked away.

Anyhow, I would think that 2 2 ounce layers should work....if not shreds are really cool! (just ask my 38 mm saucer at NERRF)

[edwinshap1]

Man, that was cool! Wonder how much wind & what motor. Flew mine on a K260 in 20+ at RGIX for a 150 yard walk but it burnt out about 300 feet above the ground. It just never got more then 800, sorta walked away.

Anyhow, I would think that 2 2 ounce layers should work....if not shreds are really cool! (just ask my 38 mm saucer at NERRF)

not when i'm looking to destroy a $180 borrowed case lol, but i do agree, it'll look awesome


Update: both layers of glass are on both top and bottom. I'll have some glass sanding to do tomorrow before the paint goes on, but then i'm on the home strech

[edwinshap1]

Rocket is finished!!!

2 layers of 2 oz glass along the entire foam body...really really strong. Got the decals on, and it looks pretty good...from a distance

Pic 1: Bottom of the rocket. 54mm aeropack retainer in place.

Pic 2: Decals...STOP sign

Pic 3: The body tube and nose cone are painted a metallic silver...it's really really shiny in the light.

[bandman444]

What is the other hole on the bottom for?

Bryce

[edwinshap1]

What is the other hole on the bottom for?

Bryce

it's a 1/2" LL hole. spaced it far enough away from the main body that i wouldn't have any issue as far as the spokes, and most of the weight is right in the saucer anyway. i can use upto a 17" long motor, so a 54/1706, or a pro54 4grain. don't really intend to go much over that in thrust, but it's definitely strong enough