Level 2 project - Blue Pheonix 4

[Dw]

Hello all,

After a long delay and after the disaster of the 5th flight of my level 1 project ( sucuessfull level 1 ) when the shock cord snapped and the rocket came down in 3 peices, forward section sideways, parachute alone, and booster section came in ballistic hitting a truck dead square on the cab.

I am back to see what kind of trouble I can get into with a Level 2 project.

Rather than build from scratch this time I decided on a kit, AAR's Blue Pheonix 4, I am told that I am the first customer of that rocket, first to order, I doubt I will be the first to build it as I plan on taking a long long time building it.

I received it a few weeks ago, but other life issues intervened and I have been unable to start on it until this weekend, and as it is, I will probably only be able to spend an hour or so with it.

So it is going to be a long slow build, but I wanted a thread here for people to make suggestions, give me ideas, and general support.

Here is what the kit looked like.

http://dwightandhelene.smugmug.com/gallery/8891932_6Dd2R#589739883_XkhM3

I will be adding to that gallery as I build it.

I plan to use 12 min Epoxy on most of it, possibly some 30 min when I need thinner stuff, I figure that 12 min epoxy is stronger than any of the other materials going into the rocket. In fact my disaster showed me beyond any doubt that the 12 min epoxy will hold, not a single fin fillet cracked, even when fins were snapped in half.

I plan on replacing the entire harness with 1/2" tubular Kevlar ( already ordered )
I plan on using 2 large fireballs from Giant Leap ( if there is room for them )
I plan on firing ejection charges forward and back from the AV bay.
I plan on using a G-Wiz LCX altimeter and thinking of going duo with a Perfect flight altimeter as a backup.

I have never done any electronics, never dual deployed, never worked with a fiberglass nosecone, or built a 54mm motor tube rocket before.

I already purchased a AeroPak flanged motor retainer including a 54-38mm aluminum quick motor adapter.

It came with a 60" parachute, rather military looking ( I like it )

No drogue so I will figure that out later.

This is going to be fun.

I hope you guys don’t mind if I start asking a whole lot of questions about directions I could go here.

[troj]

You're off to a great start on your plans!

And please, feel free to ask any and every question you have.

-Kevin

[Dw]

Thanks Troj, problem is... I will have too many.

I am not worried about most of the construction of the rocket itself, Fins, yeah they are 1/4" and quite thick but I have mounted fins before, not a big deal. I am going to tape them together this weekend and flatten out the root a little bit first with some sandpaper before I start rounding the edges.

Never used this kind of flanged engine retainer before, but it looks simple enough, and the instructions are quite clear. Not too worried about that ( I will post more pictures this weekend )

Where I am going to have a billion questions is about the AV bay.

Do I glue one end shut? Things would be more accessible if I didn’t.

Do I use terminal blocks and hardwire to the inside of the AV bay, or do I build a pass system for the shooter wire on the e-matches ( seen both ways )

My current plan ( talk me out of it if you like ) is to use small copper or plastic end caps for ejection charges, I probably wont use canisters at all, but use small caps that will hold the BP, and tape them shut ( with some filler ) just like you do motor ejection.

I figure a circle of masking tape and then tamp dog barf filler on top of that and then tape them shut like motor ejection.

But I am ready to be talked out of that if people see problems with it.

I plan on beefing up the AV bay bulkheads that came with the kit, I am undoubtedly over doing it, but that is just my way.

The goal for me isn’t the highest flyer, I am trying to make a tremendously reliable rocket.

[Dw]

Here is sort of a general idea of what I am intending for ejection charges.

Take 2 ( one for each altimeter per end ) small copper end caps, drill a hole in the bottom and bolt them to the AV bulkhead.

Then just drape an e-match tightly over the side of it so the match head is at the bottom and the wire conforms tightly to the side of the cap.

use 2 matches per charge in parallel ( not series )

Pour in Black powder, make a masking tape seal ( circle ) tamp that in, then fill the cap with dog barf fireproof insulation and then just treat the cap the say way I do on engine ejection with masking tape.

Is this making any sense?

and am I making any bad assumptions here?

The fact that the caps are copper bother me a little, but it shouldn’t be a problem, I would be doing full resistance testing after completed. If I can find plastic caps that will work I will probably switch to those, easy to replace as well.

[brianc]

Here's a starting point for your Av Bay construction-

http://www.vatsaas.org/rtv/construction/avbay/avbay.aspx

[Dw]

Yep... saw that brianc.. and that would be the terminal block way to do it, and to be honest I think I am indeed leaning that way.

here is another interesting way.

http://www.vernk.com/Construction/AngelfireAltimeterBay.htm

[brianc]

[Dw]

Another thing I am thinking about ( over thinking )

Is how to arm it all, particularly if I use 2 altimeters?

My first thought was Key Switches... but I have seen an advantage to the Screw type switch as well.

Key switch - as I understand them

Pro- looks cool and you can have those cool flags and it is obvious if you have armed your electronics or not

Con - The switch is actually mounted on the side of the altimeter bay so the wiring has to go from the sled to the side of the bay along with through each bulkhead on the ends

Screw switches - as I understand them

Pro - I can mount them on the sled itself so that a small hole ( or 3 ) in the 1" band around the altimeter body can be used to pass a screwdriver to arm the altimiters, all the wiring stays on the sled.

Con - not obvious that your electronics are armed.


Right now... I am leaning toward the screw switch so I can keep the arming wiring on the sled itself. But with 2 altimeters, and one of them the G-Wiz LCX that really means 3 switches, one for the LCX, one for the Pyro batteries of the LCX, and one for the Perfect flight which includes its battery.

[Dw]

Another off the wall question

does anyone make loops in the end of tublar kevlar like this?

It looks neat...

http://www.geocities.com/rdh82000/Tips/kevlar.htm

[brianc]

[Rubr_Duky]

I use "dehate loops" in my tubular kevlar harnesses. I think they work great. I had one rocket come apart at Mach 1.6 and the kevlar held everything together, despite at 24" zipper in a tube made of two layers of 5.6oz carbon fiber and one layer of 5 oz fiberglass.

I found some brass tubing at my LHS, and another brass wire. With a hook in the brass wire, on one end, and one end of the brass tubing cut at a pretty good angle (all burrs removed), you work your way into the TK, and then out again, and with the hook in the wire, you feed that through the tube, and retrieve the end of the TK. Make sure you've either got a ring, or something in place, or you have room to put a quick-link in the end. Pull all of your brass out, and work it to get the fit you want. I used a bit of blue tape to wrap the loose end, and keep it from coming out, but I find that after you get it situated, and load it up real good, unless you try to un-do it, they should stay where you put them.

One other thought. I usually make the amount that I loop back through the TK equivalent to the length that I am going to be using to pack it. IE - if I'm going to figure-eight it through my pinky and thumb during prep, then the length of the tail that goes back through the TK will be from pinky to thumb. Do some playing, and see what you think.
_________________
RD


TRA #10462 L2
www.rocketryonline.com

[Dw]

Rubr Duck

I like it!

thanks.... I plan to use that method then!

BrianC.... not sure I can describe what I am thinking of, but the screwdriver would get no where near the electronics on the way I am thinking. I have seen those screw switches that mount onto the altimeter and I agree, I would not do that, I’m not that steady handed.

Im talking an old piece of coupler from the old ruined rocket, doubling it in thickness, making it into a mounting bracket and mounting it on the sled so that it slides into the bay very close to the inside edge of the coupler, and the screw switches are mounted on that scrap of coupler very very close to the airframe, like 1/4 inch

I will try to make a drawing

( I also suppose I could do the same thing with key switches now that I think about it, not sure how large the holes would have to be for that )

[brianc]

Ohhh. OK, I got it. Musta had the Parrot on board screw
switch on the brain...

Here's another way to do what you're talking about, but
without the extra coupler.

http://www.rocketreviews.com/featured/tip_featured29.shtml

[troj]

[troj]

On your switch question, one possibility is to mount screw (or other) switches to the outside of the av bay, run to a polarized standard connector. Then, put the opposite end of that connector on your altimeters. When you put the altimeters in the bay, you plug in the leads and voila! And because it's polarized, it's difficult to wire things backwards.

What I do for end caps on av bays is two bulkheads; one that matches the ID of the airframe, and one that matches the ID of the coupler I make the av bay out of. They get sandwiched and epoxied together; one sandwich for each end, with all-thread running between. This way, the ends are easily removable.

-Kevin