*Centuri* Phoenix Bird
 

Hello All,

Last night I was looking up documentation on the Centuri Phoenix Bird (*not* the Estes re-issue) and its higher-powered sister, the Enerjet 1340 Sounding Rocket. The Estes Eliminator kit contains all of the Phoenix Bird's airframe parts except one--the plastic tubing connector, which was a molded plastic component. It was a cylinder with blunt conical front and rear ends (which fit inside the body tube and the payload section tube; the rear cone had [I think] a molded-on loop, not necessarily circular, to which the parachute and the shock cord were tied, and:

When the rocket was fitted together for flight (or display), the only portion of the plastic tubing coupler that was visible was a short section in its middle, which was the same diameter as the 1.34" O.D. body and payload tubes (Centuri #13 and Estes BT-56 designations). Does anyone have the dimensions of this #13 tubing coupler (particularly the length of the exposed "ring section" that matches the body tube diameter)? Re-creating this part would enable the Estes Eliminator to be converted to a Centuri Phoenix Bird or Enerjet 1340 Sounding Rocket clone.

Many thanks to anyone who can help!

It's .10".

http://www.oldrocketplans.com/enerj...340/enj1340.pdf

Where are the plans (if any) for the Centuri Phoenix Bird?

Thank you! I'm glad that it's also a nice round number (classroom rulers aren't usually divided into 0.10" divisions, but steel rules are). I've looked online for Centuri Phoenix Bird instructions, but there don't seem to be any (there are for the Argus, though, on JimZ's website).

That's OK, never mind. I see on Ninfinger's site the Phoenix Bird's dimensions are in the 1978 Centuri catalog. Same diameter, just slightly shorter than the Enerjet 1340. Can I pester you with a couple of questions? How do you intend to replicate that part? 3D printed plastic or balsa coupler, perhaps? And are you going to add the tiny strakes to the Eliminator fins, or leave as is? Do you have a scan of the original decals? Or will you be using the Estes version? Appreciate your feedback.

I apologize for the delayed reply; either YORF or my ISP does some kind of "system house-keeping" late at night, which makes it impossible to open YORF to read or post anything. I wouldn't be making the tubing connectors myself. I was just gathering information (on my own) for another YORF member who might--but might not--be interested in 3D printing them. The Eliminator (see: http://www.amazon.com/Estes-1950-El...t/dp/B0007UDS84 ) appears to have the little forward fin strakes.

I've got to get me a white lab coat so I'll look smart. :cool: :eek: :rolleyes:

I always thought the white lab coat in that photo looked ridiculous.

I'm not Jason but.....

When I used an Eliminator to make an Enerjet 1340 clone I just used a BT-56 stage coupler (the regular fish paper sort) and put a 1/10 inch long ring of body tube in the center of it. The tube cutter I have (one of Chris Michelssen's but it is similar to the Kuhn cutter currently available) with a fresh blade made cutting a ring that small not terribly difficult.

Then, a ply disc from Semroc inside with a screw eye made a functional replacement part that looked right on the outside.

I had thought about replicating it that way, too. But Bruce Levison ('teflonrocketry1') is working on 3D printing--among other things--the Centuri #13 (Estes BT-56) plastic tubing connector that was used in the Centuri Phoenix Bird and the Enerjet 1340 Sounding Rocket.

Does anyone have the lengths of the body tubes in the kit? I know that it uses ST-13 tubing.

Not directly, but going by its 26.3" overall length (see: http://www.ninfinger.org/rockets/ca...-2/782cen6.html ), and the 28.0" long Enerjet 1340 Sounding Rocket's component dimensions (given on page 2 here: http://www.oldrocketplans.com/enerj...340/enj1340.pdf [its main body tube was 13" long, and its payload tube was 8" long]), it should be possible to derive them. One difference between the two was that the 1340 Sounding Rocket used quite large, high-impulse Enerjet motors, and the length of the protruding rear portion of the motor counted as part of the 28.0" length. What was the typical "protrusion length" for these motors? (For 13 mm motors, it's 1/4", and for 18 mm motors, it's 1/2".) *ALSO*:

This picture of the "bulbous payload section" 1340/20 (see: http://www.oldrocketplans.com/enerj.../enj1340-20.pdf [its main body tube--to the rear edge of the fin unit, the drawing seems to show--was 12.0" long]) shows the protruding motor pretty well; it looks like it's protruding 1" or so behind the rear edge of the fin unit (there's also a short length of motor tube, or body tube, just behind the rear edge of the fin unit). Here (see: http://www.ninfinger.org/rockets/ca.../72ejetcat.html ) is the 1972 Enerjet catalog, which shows the big motors the 1340 Sounding Rockets used.

In addition to the Centuri Phoenix Bird (see: http://www.ninfinger.org/rockets/no...a/79cen010.html ) and the Enerjet 1340 Sounding Rocket (see: http://www.oldrocketplans.com/enerj...340/enj1340.pdf ), the Estes Discovery (see: http://www.ninfinger.org/rockets/ca...6/86estcov.html and http://www.ninfinger.org/rockets/ca...87/87est10.html ) and the Estes Challenger II (a 24.25" long, "D"-powered launch vehicle for the AstroCam 110, although it came with the regular BT-56 nose cone, see: http://www.ninfinger.org/rockets/ca...84/84est54.html ) also used the Phoenix Bird/1340 Sounding Rocket plastic fin unit and nose cone. I don't think (although I'm not 100% sure, having never had them) the Discovery and the Challenger II had payload sections, but simply ejected their nose cones, to which their parachutes and shock cords were tied.

Gee, guess I had an upscale Enerjet 1340 without realizing it. Will look into resizing and repainting my Eliminator XL bird. Or maybe Phoenix Bird XL?

Stick a delta wing on it rather far back, and you've got a "*very* freely interpreted" Pegasus XL ( http://www.google.com/search?q=pega...iw=1440&bih=794 )... :-)

By process of elimination, the length that the motor tube protrudes is .6" ( Overall length minus nose cone length, minus payload tube and main body tube with fin can length, minus coupler length). I have doubts that an Estes E2X rocket can handle a 24 or 29mm composite propellant motor, however.

Jason-

I glanced through the thread somewhat quickly (and possibly you've already noted it), but the 1340 used heavy walled tubing that was thicker than the standard Centuri ST-13 tubing (Semroc/eRockets would have it). The 29mm motor mount tube (also heavy walled) is a "glove fit" inside that tubing.

The O.D. of this heavy walled ST-13 tubing is the same as the regular ST-13 tubing, but because it used a thicker tube, the nosecone was different than that used in the Phoenix Bird, Eliminator and other kits that made use of that similar looking plastic cone. I think the cone profile was the same; what was different is the 'shoulder' had a smaller O.D. to account for the thicker tube wall.

That said, the nosecone and fin unit from an Estes Eliminator can be used to make a nice clone...it just won't be as 'beefy' as the original 1340. The fin unit is the same between all kits that have used it off and on now for 46 years. It holds up well under F power from what I understand, but I think Jerry Irvine has reported fin flutter/fin breakage under G power.

Earl

Funny you should mention that. Just received Frank Burke's Pegasus X R/C rocket glider kit.

https://dynasoarrocketry.com/?page_id=1640

Would have loved to build the TMRK Pegasus kit, but they went defunct, plus it's a tad out of my budget ( Okay, more than a tad).

http://tmrk.rocketshoppe.com/pegasus.htm


Looked into cloning it, but the wing to body transitions look very difficult.

With 3D printing, this is no longer a problem; files could be generated for printing "wide shoulder" (Phoenix Bird) and "narrow shoulder" (1340 Sounding Rocket) nose cones and tubing couplers. Thank you for reminding me about the thick-walled tubing (*and* for pointing out where it can be sourced!); looking at the 1340 and 1340/20 pamphlets last night, that notion--about the tubing thickness, given their very powerful motors--was "tickling" at the edge of my awareness, and:

I hadn't known that the 29 mm motor tubing "sleeve fits" into that thick-walled body tubing--that is good to know! I have relayed your information to Bruce Levison ('teflonrocketry1'). Thank you also for passing along Jerry Irvine's report about the fin unit's "F-power limit" (for avoiding fin flutter and breakage under G power). F power is plenty strong for me, but maybe (for those who'd like to use G power safely) a somewhat "beefier" duplicate of the fin unit could be 3D printed (slightly thicker gauge, perhaps?)--or maybe the fin unit in the Estes Eliminator might be strengthened with Kevlar veil and epoxy--to withstand the stresses from G motors.

Whew! That TMRK Pegasus kit should have a gold lamé parachute for that price! :-) The R/C one would make a good PSS (Power Scale Soaring [such slope-soaring models of powered aircraft not uncommonly have such over-sized wings and tail surfaces to permit better gliding performance]) model.

I pulled out my original Centuri Phoenix Bird while at home for lunch. I brought the upper section back with me and can tell you the following: The visible adaptor has a coupling 1.5" long with 1" to hold onto the lower tune. The remainder is a .5" cone with a eyehook for connections. I assume the upper coupling is the same, but since its been glued together for 39 years, I can't tell. The middle part that is the same diameter as the tube is .875" long. The upper tube is 7" long. I didn't bring the lower half so I can't give you a length on that.

Mike

Thank you! You also noted a dimension that is different than in the Enerjet 1340 Sounding Rocket, which--along with the 7.0" payload tube length--is good to know. In the 1340, the "tube diameter-matching portion" of the tubing coupler (the only portion of it that's visible when the rocket is assembled for flight (or display) is 0.10" long (see page 2 here: http://www.oldrocketplans.com/enerj...340/enj1340.pdf ) I had assumed that this was also the case for the Centuri Phoenix Bird's tubing coupler (both rockets are the same outside diameter, but the 1340's body & payload tubes are thicker-walled), and this difference enables perfect replication fidelity to be achieved, and:

Knowing from the Centuri catalogs that the Centuri Phoenix Bird is 26.3" long, from your measurements that its payload tube and exposed tubing coupler section are 7" and 0.875" long, respectively, and from the Enerjet catalog that its nose cone is (not including its shoulder) 6.40" long, the Phoenix Bird's lower body tube is 12.025" long (I wouldn't be surprised if it's actually 12.00" long, since the Phoenix Bird's length is only given to tenths of an inch, not hundredths [or the Centuri nose cone might be 0.025"--less than 3/100ths of an inch--shorter than the Enerjet one, which wouldn't be noticeable unless measured]).

26.3" - (7" + 6.40" + 0.875") = 12.025"

LOL I wore a blue lab coat in the mechanic's shop in high school... kept my clothes clean and didn't have to change clothes or worry about getting greasy/oily...

Later! OL J R :)