Erzatz Enerjet 1340 "clone" Phoenix Bird (etc)

[RWmarlow]

Was playing around in the parts box this AM and found a Quest Fin Can that slips over the 30mm Tubing. That and some digging around in the Body tube and nose cone bins and kind of came up with a "Phoenix Bird" since I don't have any Ideas about the dimensions of The 1340 model...anybody care to hazard a guess as to what might "look" right in terms of payload section /nose cone etc....well ok it's not even close...but it still looks like something that was something back when plasctic came on board in the early seventies... pics as I get them !

Thanks

RM

[barone]

Have you looked here/ I'm not sure if I understand what you're asking for.....

http://www.oldrocketplans.com/enerjet/enj1340/enj1340.htm

[Jerry Irvine]

The 1340 had the same OD as the Centuri ST-13 Phoenix Bird, but had thicker wall tubing for "Enerjet 30" motors. (G)

The molded nose cone and coupler also accomodated the thicker wall tube. It would be cool to have Estes do a run of those plastic parts for some third party to purchase and sell over time. They molded it in red initially. Both the fin unit and the nose cone and payload coupler combo.

Lee told me several engineering changes he wished he would have made to the fin unit.

Just Jerry

[RWmarlow]

Thanks,

That does help....a lot...you can almost see a family resemblance...,I'm having fun with it...and will probably go with a retro paint scheme (though one could almost see 70's "GROOVY" on it...glue drying taking build pics right now

RM

[RWmarlow]

Thanks for the Input Jerry!

[hcmbanjo]

I've got a Enerjet 1340 build thread on my blog right now:
www.modelrocketbuilding.blogspot.com

Mine is being made from a Centuri M.A.R.S. "kit".

Stop by, the specs and Enerjet links are there at the first post.

[Jerry Irvine]

The Enerjet 30's were case bonded coreburners with low burning rate propellant so they were "Mach buster" motors. The Minimax thicker wall tubing was slight overkill for black powder E and F motors, but certainly not for Enerjet motors.

Ironic that Enerjet kits used Centuri not Minimax tubing, eh?

Just Jerry

[Jerry Irvine]

Unpublished and/or commercial Enerjet kits used Mini-Max tubing. The 1340 was 1.34" OD x 1.25" ID. The 2250 was 2.25" OD and the 2650 was 2.65" OD and the three kits used 29mm motor tubes of 1.14" ID x 1.22" OD.

The 2250 had a severe interference fit for the three 29mm motor tubes in the 2.25" OD tube to the extent severe tube crushing was necessary.

The 2650 had a snug fit of the three 29mm motor tubes in the 2.65" OD tube.

It was years until my 2650 stopped flying with 3xEJF67, 3xEJG76, 3xFSIE60, 3xFSIF100, 3xCRG60, 3xPJG88.

The best flight ever was 3xFSIF100 staged to 3xUSRJ160. That was a day.

The most common flights were 3xFSI F100-10 and 3xFSIF100-0 to 3xFSIF100-10. Dozens. Lonnie asked me where all those motors went. I laughed.
http://www.oldrocketplans.com/enerj...340/enj1340.htm
That document makes reference to motors from 9 to 40 pound seconds (29mm) and the only ones my friends ever saw were up to 30 pound-seconds. 30 is 120N-s so 40 is 160 N-s. Has anyone ever seen a 160N-s EJ motor?

Jerry

[RWmarlow]

Here is the parts list as it sits right now....

Quest:

PFU 30 Plastic fin can
T30 Tubing
PNC 30 Plastic Nose Cone (this will be changed out into something a little more "right" looking.)

The Kevlar Shock cord, Launch Lug, engine block and streamer all came from the parts bin...you know when you order this much kevlar thread to get the order up to the minimum...etc.

I figure on plenty of nose weight to get the thing stable but i'm not so sure...(no access to rocsim)

Right now I'm toying with the Idea of an OOP F14-9J to accidently fall into the back end of the rocket...maybe that or one of these really antique USR 29mm F20's that I have a box of (shhh)...I didn't say anything about when and or if i'd use a un-certified motor :P



Thanks


RM

[Jerry Irvine]

Don't both NAR and TRA now have some complicated provision for using uncertified motors?

Take some photos of those USR motors and I will have them added to the historical section of the website. Take several. They were great motors. They were certified for about a decade.

Just Jerry

[snaquin]

It was years until my 2650 stopped flying with 3xEJF67, 3xEJG76, 3xFSIE60, 3xFSIF100, 3xCRG60, 3xPJG88.

Jerry

I remember you posted a link to a couple of pictures years ago that had your son holdingg an original 2650 rocket. One shot of the front and one from the rear holding it on his shoulder. It was painted in the traditional flat black and bright orange and bore the scrapes and scars of many flights on it.

.


Has anyone ever seen a 160N-s EJ motor?

Jerry

Nope ..... do tell.

:)

.

[snaquin]

Here is the parts list as it sits right now....

Quest:

PFU 30 Plastic fin can
T30 Tubing
PNC 30 Plastic Nose Cone (this will be changed out into something a little more "right" looking.)

The Kevlar Shock cord, Launch Lug, engine block and streamer all came from the parts bin...you know when you order this much kevlar thread to get the order up to the minimum...etc.

I figure on plenty of nose weight to get the thing stable but i'm not so sure...(no access to rocsim)

Right now I'm toying with the Idea of an OOP F14-9J to accidently fall into the back end of the rocket...maybe that or one of these really antique USR 29mm F20's that I have a box of (shhh)...I didn't say anything about when and or if i'd use a un-certified motor :P



Thanks


RM

RM,

Is that fin can a 3 fin or 4 fin unit? Reason I ask is if it is a 3 fin unit with similar sized fins to say a Nike Ram or Estes Eliminator fin can you may need just a tad of nose weight, If you intend to use the F14-9J or USR 29mm F20's without a payload.

I've built several versions of the 1340 with Estes plastic PNC-56, Centuri plastic PNC-132 (thanks SEL) and custom hardwood cones Sandman turned for me to fit Semroc LT-125 thick walled (SLS) type tubing. I cut the nose cone shoulders and used cardboard coupler tube to fit the ST-13/BT-56 sized cones to the smaller ID of the LT-125. The plastic nose cone versions I cloned rounded out CG/CP margins between 1.4 and 1.5 calibers. The hardwood nose cone obviously was a little better margin.

No added nose weight needed with the 1340 and I've flown several of mine on F and G motors safely without a payload. 1340 was a great design.

:)

.

[snaquin]

A link to Bob Sanford's EnerJet article from LAUNCH Magazine for anyone surfing here to YORF in search of additional EnerJet history / information:

http://launchhistory.com/history/centuri/4-the-enerjet-story?showall=1

.

[Jerry Irvine]

Reason I ask is if it is a 3 fin unit with similar sized fins to say a Nike Ram or Estes Eliminator fin can you may need just a tad of nose weight, If you intend to use the F14-9J or USR 29mm F20's without a payload.
The USR F20 as a phenolic case SU motor was VERY low mass and moderately higher performance than a similar reloadable, or modern day molded case SU. These motors were far lower mass than BP motors of even half their power or especially other fiberglass case SU motors such as Enerjet, Internal Ballistics, Composite Dynamics, Vulcan, or others.

These were technically sweet motors tailored for model rockets.

Jerry

[Earl]

The Enerjet 30's were case bonded coreburners with low burning rate propellant so they were "Mach buster" motors. The Minimax thicker wall tubing was slight overkill for black powder E and F motors, but certainly not for Enerjet motors.

Ironic that Enerjet kits used Centuri not Minimax tubing, eh?

Just Jerry

This is kind of an old thread, but I was searchin' around for some info and came across your comment Jerry, which raises a question that has always caused me to scratch my head about Enerjet kit parts.

That question is: Why in the world did Centuri do away with all their truly heavy duty body tubes and parts (i.e., all the Mini Max stuff) when they officially rolled out the superior (and greater impulse) Enerjet composite motors?

Those Mini Max parts would have been great for Enerjet use, but Centuri did away with all that in their first Enerjet catalog!

Anyone know the reasoning behind that decision by chance?


Earl

[Jerry Irvine]

Me too on the head scratch. Perhaps to have improved commonality with Centuri molded plastic parts. The only Minimax style tube molded part I recall seeing was the 1340 payload coupler and nose cone combo. The OD fit ST-13 so the plastic fin unit is the same as Estes now uses with the BT-56.

However the 1340, 2250 and 2650 all used MM tubes and the 2250 and 2650 used balsa cones like MM did too.

Jerry

[Earl]

Me too on the head scratch. Perhaps to have improved commonality with Centuri molded plastic parts. The only Minimax style tube molded part I recall seeing was the 1340 payload coupler and nose cone combo. The OD fit ST-13 so the plastic fin unit is the same as Estes now uses with the BT-56.

However the 1340, 2250 and 2650 all used MM tubes and the 2250 and 2650 used balsa cones like MM did too.

Jerry


Yeah, very well could be to provide that commonality....Centuri had a pretty good compliment of plastic cones and matching tubes for their standard line by 1972.

But, one would think they could have left the really heavy duty Mini Max tubes and parts in stock as well, along with their 'standard' model rocket parts. By and large, I liked most of the Mini Max kit designs as much (and in some cases more) than I did the Enerjet designs. They did carry over the somewhat modified Aero-Dart into the Enerjet line, but I think they could have kept the entire Mini Max line and incorporated them into the 'new' Enerjet kits and called them all 'Enerjet' if they wanted to.

But I think the heavy duty stuff could have co-existed just fine with the newer Enerjet line. It's all academic now, and history shows that the declining economy and sliding interest in the space program would put a rather hasty end to the Enerjet line, and that would have occurred whether they had kept the Mini Max stuff or not.

But I've always wonder WHY they dropped all that nice heavy duty Mini Max stuff RIGHT when they finally introduced motors that could really use those kind of parts.


Earl

[snaquin]

Yeah, very well could be to provide that commonality....Centuri had a pretty good compliment of plastic cones and matching tubes for their standard line by 1972.

(snip)

Earl

On another note what I find interesting is that some of the EnerJet models that were pictured in the brochures used Centuri parts. As you mentioned Centuri had a large offering of plastic cones and airframes in their standard line so this only makes sense.

The EnerJet 1340 pictured here in the brochure that Chris Timm supplied to YORP shows what appears to be a Nike-Ram using the EnerJet plastic fin unit. Pretty much like flying the Phoenix Bird/Maniac on F and G motors since that PNC-132 was sitting on top of ST-13 airframe tubing. :D

http://www.oldrocketplans.com/enerjet/enj1340/enj1340.htm

The line drawing on the back page shows the dimensions for the longer cone that Jerry mentioned would have used the unique EnerJet nose cone and coupler to fit the thicker walled airframe. I would assume for flight testing they would have used parts on hand before committing to the manufacture of the EnerJet cone/coupler assembly.

The 1340/20 is interesting as well. I wonder if the intent was to use ST-13 tubing for the production model (if it was ever produced?) since we know the Centuri Egg capsule fits ST-13 tubing and would not have fit the thicker walled airframe of the 1340. The reason I mention this is I wouldn't think a ST-13 based 1340/20 would have survived well on F and G motors with a payload in the front and would have probably stressed the airframe at the capsule shoulder. I wonder if there were plans to remold the Egg capsule to fit the 1340 thick walled airframe for durability?

If not, then this EnerJet model would have used standard off the shelf Centuri ST-13 airframe.

http://www.oldrocketplans.com/enerjet/enj1340-20/enj1340-20.htm

Too bad Larry Brown isn't a member here as it would be pretty cool to chat with him about such things

:)

.

[Earl]

Steve-

Some good points.

On the 1340 brochure, I've historically assumed that the photo on the front of Larry Brown and Mr. Fox was a 'pre--production' 1340 that was made with the standard #13 Centuri (shorter) plastic nosecone before the longer production 1340 nosecone was available. However, that '1340' on that brochure front cover DOES look too much like a Nike Ram with plastic fin can, as you stated. They should have held off on brochure photography until they had final production parts OR at least 'mocked up' a balsa cone to resemble the final longer plastic cone for the 1340.

On the 1340/20, that's ANOTHER point (as you mention) that I've long wondered about: did the 1340/20 sport a 'different' molded egg capsule that would fit the heavier walled tubing of the 1340 booster?

From all that I have garnered, the Enerjet egg capsule fit *standard* Centuri #13 tubing. THAT tubing--as you state--certainly would NOT have held up very well at all with a high-thrust F or G motor in the booster and some decent-sized payload in that elongated two-inch diameter payload capsule up front. Can you say "instant crimp"?

So, it does beg the question: Had there been plans for a different egg capsule for the 1340/20 that would fit the heavier walled 1340 tubing or not? I have never heard that there was, nor have I ever heard of anyone seeing a 'production' 1340/20 kit or assembled rocket.

Jerry, did you ever see or hear of a 'production' 1340/20 rocket with any kind of a different 'Enerjet' plastic egg capsule on it that fit the heavier walled tubing?

Earl

[Jerry Irvine]

There was only one egg capsule and it even fit ST-13 a bit tight.

There were several non-production rockets displayed in public which was a nod to scratch builders.

It is helpful in hindsight to note the Enerjet line was not well adopted by dealers and ultimately failed entirely in the marketplace. That fact alone shows any plans to make more molds were killed by results and the first 6 or so kits ended up being EOL.

The 1340 was a real product with a plastic fin unit, Minimax tubes (1.25 x 1.34"), associated molded cone and coupler, and motors, in addition to the consumer line. I think they hoped there was a growing commercial market beyond consumers.

They were wrong, and even now the market for commercial rocketry is weak and not well addressed by either manufacturers, VARs, or consultants. If that were to someday change there are certainly enough applications to do. The Centuri parts could readily handle 29mm E-H flights with payloads installed.

But the few companies servicing that market were targeted by TRA for shunning which shifted manufacturer resources in bad directions. I see Bob reminds us of the Estes/Vulcan video sent to DOT/NFPA (ie. not the public at all) as some sort of conspiracy against Errortech, but remember they were shipping reloads that were not DOT approved or NAR/TRA certified to consumers for years before they came into compliance.

The firms with first to manufacturing reloadable systems, who simply said get approved before shipping, USR and Vulcan, were shunned and attacked by TRA/AT as a means to assure their inferior RMS casings got to market first to ultimately assure uptake. The scheme worked, albiet at the cost of a total lack of ethics. The details of this series of events is well hashed out on rmr and need not be repeated here. The USR single snap ring reloadable motor system was released for pre-order at the 1-90 Ocotillo launch, which was published in the newsletter. View it. RMS was released for pre-order later that summer. The USR system was submitted and TESTED for TRA cert in 2-91. TRA (Kelly/Rogers) itself certified them as Kosdon not USR as submitted.

It is real, did happen, and had consequences I highlighted here.

Ironically it also harmed the overall market size to the extent even Aerotech with a virtual monopoly is financially marginal even after decades of "dominance".

They created and dominated an anthill. ~3000 HPR users worldwide. :(

Historically Aware Jerry

[RWmarlow]

Great to hear more rocket history...Back In the day Enerjet pricing was way out of the reach of guys like me when getting paid enough mowing a lawn for a 3-pack of Estes BP (1.25 USD) was considered a major score...(But a Kid could dream)

[RWmarlow]

The "Semi-Scale " (Quest 3 Fin Can) 1340 went up on an F20-8 this Morning...deployed right past apogee and recovered nicely....My last flight of the year....On a Vintage Motor!!! :)

[Jerry Irvine]

The "Semi-Scale " (Quest 3 Fin Can) 1340 went up on an F20-8 this Morning...deployed right past apogee and recovered nicely....My last flight of the year....On a Vintage Motor!!! :)Photos.

[blackshire]

Was playing around in the parts box this AM and found a Quest Fin Can that slips over the 30mm Tubing. That and some digging around in the Body tube and nose cone bins and kind of came up with a "Phoenix Bird" since I don't have any Ideas about the dimensions of The 1340 model...anybody care to hazard a guess as to what might "look" right in terms of payload section /nose cone etc....well ok it's not even close...but it still looks like something that was something back when plasctic came on board in the early seventies... pics as I get them !Sirius Rocketry, as part of its "Moldin' Oldies" line (see: http://www.siriusrocketry.biz/ishop/index.php?main_page=index&cPath=11_26 ), makes polyurethane resin duplicates (from molds created off the original parts) of the Centuri Phoenix Bird's #13 plastic tubing connector and nose cone (see: http://www.siriusrocketry.biz/ishop/index.php?main_page=product_info&cPath=11_26_35&products_id=278 ). These could be used (along with the plastic fin unit from an Estes Eliminator kit) to create an Enerjet 1340 clone, although Estes BT-56 tubing would have to be used for the model's body tube. For a higher-than-"E"-powered 1340 clone, fiberglassing the BT-56 body tube (or perhaps wicking thin CA into the tube to strengthen it) could beef up the body tube sufficiently to withstand the higher stresses. Also:-SNIP-
Right now I'm toying with the Idea of an OOP F14-9J to accidently fall into the back end of the rocket...maybe that or one of these really antique USR 29mm F20's that I have a box of (shhh)...I didn't say anything about when and or if i'd use a un-certified motor :P
-SNIP-If a rocket with an un-certified or de-certified motor flew and landed safely, and no NAR or TRA official was there to see it, did the flight really happen...?

[RWmarlow]

Thanks for the info....Maybe it's time to build a "real clone" (is that an oxymoron?)of the 1340...and to Paraphrase " Tim Deland" (Randy Quaid) from the cinema classic "Days of Thunder"...."That's MY motor in that rocket I bought that motor and that's what my boys are pushin'"....

[tbzep]

Also:If a rocket with an un-certified or de-certified motor flew and landed safely, and no NAR or TRA official was there to see it, did the flight really happen...?
Not without pictures! :D

[Jerry Irvine]

Centuri ST-13 and Estes BT-56 (Astrocam tube) are plenty strong unreinforced in any way for almost all 18mm, 24mm, 29mm or 38mm motors under full 320H with an average thrust under 80 Newtons which have a regressive trace. The more regressive the higher the practical impulse. The proven marginal SU-29-180-STD, G80 after considering lower ISP propellant and one larger drilled core to get down to exactly 160N-s, is the proven 50-50 motor for a Phoenix Bird.

Interestingly some shorter duration motors work because peak velocity is lower due to drag losses.

Jerry

[RWmarlow]

I used the Quest T-30 tubing it held up fine ....of course I havent pushed it past F20....I'm Concerned about Stability issues on a Yellow casing G-80....(No Rocsim here) :confused:

[blackshire]

Not without pictures! :DI'm sure I've used many de-certified motors, since sometimes many years have elapsed between my flying sessions. But I've always stored my motors carefully, and if I have them I will eventually use them, since I paid for them and won't throw them away. What the NAR and TRA don't know won't hurt them.

[RWmarlow]

And why does a motor get "De-certified"....

[Jerry Irvine]

Decertification is an arbitrary rule installed to deal with one bad example from the early 70's. That one bad example could have been decertified without automatically decertifying all motors. This is a stroke of the pen change that has been proposed to but not adopted by NAR and by reference NFPA and TRA and possibly CAR.

This is a respected group of folks. How about a letter writing to president@nar.org to seek this sensible and needed change.

The strongest reason to change the rule is in some states a "decertified motor" becomes a "destructive device" despite common sense, physics, and contrary legal treatments in other laws, regulations, and guidelines.

Jerry

[Bill]

And why does a motor get "De-certified"....


The most common reason has been beaten into glue in this thread... http://www.oldrocketforum.com/showthread.php?t=8925


Bill

[Jerry Irvine]

Ignoring facts to reinforce the status quo may qualify as beating a dead horse into glue to you, but it looks more like a conclusion supported by whatever argument that is needed to support the status quo and that pre-conceived conclusion.

The very idea of any decertification in any other industry or product line would require a court order to accomplish, which is both difficult and expensive.

Jerry

[Initiator001]

Back when Estes was making the Maniac kit (Same as the Eliminator now just different colors) I modified several with 29mm motor mounts. I flew them on AeroTech F25-9W motors. I 'landed' one of my modified Maniac models in a tree at NARAM-41.

At NARAM-42 I had a new Maniac kit built for use with a 29mm motor. This time, however, it would be no whimpy flight. ;)

Matt Steele gave me a Dark Star F62-9 motor to use in the model. The F62-9 was NAR certified at the time but was not put into mass production by Estes. Matt also had a Dark Star G70-10 I could fly if my Maniac survived the F62-9 flight.

The Maniac was prepared with the F62-9 and placed on the launch pad. At ignition, the model lept into the sky and promptly disintegrated. I watched the video I took of the flight recently and it appears the body tube failed.

I recovered the 'pieces' and discovered that the leading edges of the fins on the molded fin can had broken off or split. I guess I was pushing Max-Q for that part. :eek:

[Rocketcrab]

Back when Estes was making the Maniac kit (Same as the Eliminator now just different colors) I modified several with 29mm motor mounts. I flew them on AeroTech F25-9W motors. I 'landed' one of my modified Maniac models in a tree at NARAM-41.

At NARAM-42 I had a new Maniac kit built for use with a 29mm motor. This time, however, it would be no whimpy flight. ;)

Matt Steele gave me a Dark Star F62-9 motor to use in the model. The F62-9 was NAR certified at the time but was not put into mass production by Estes. Matt also had a Dark Star G70-10 I could fly if my Maniac survived the F62-9 flight.

The Maniac was prepared with the F62-9 and placed on the launch pad. At ignition, the model lept into the sky and promptly disintegrated. I watched the video I took of the flight recently and it appears the body tube failed.

I recovered the 'pieces' and discovered that the leading edges of the fins on the molded fin can had broken off or split. I guess I was pushing Max-Q for that part. :eek:

Or, in other words Bob, you exceeded the speed of plastic?! ;)

[Jerry Irvine]

The Maniac was prepared with the F62-9 and placed on the launch pad. At ignition, the model lept into the sky and promptly disintegrated. I watched the video I took of the flight recently and it appears the body tube failed. I recovered the 'pieces' and discovered that the leading edges of the fins on the molded fin can had broken off or split. I guess I was pushing Max-Q for that part. :eek:The circa 1999 F62 uses the exact same grain geometry as its long time predecessor the U.S. Rockets F40/F80/F160. EX guys can do the math on this one. 2 grains 1.25" long, 5/16" core and a propellant OD of 0.96". Almost flat shape. The propellant used in the F62 was developed by Scott Dixon of Vulcan and had a very high ISP for its size and good ballistic properties. The burning rate and time was right in between our circa 1988 F40/F80 motors. The total impulse was almost exactly 80N-s.

Jerry

[RWmarlow]

:D I went old school...a tiny pat of clay with a G 80 and it looks good with a "string test"....guess we will see what happens when the wind dies down....Will take before and (hopefully) after photos with the results