How about the ol' Egg Crate ?
 

Can anyone help me with plans for the old Centauri Egg Crate ? I know it's a BT-60 (estes equivelent) body and a BT-70 payload section, but I need tube lengths, and a fin pattern would be REAL nice !

Anyone ? You would have my undying gratitude ! That and $3.75 buys you a latte at Starbucks......

Lee

The payload section is ST-20 which is larger than BT-70.

I know, but the difference is a little over 1/10 of an inch, not enought to matter to me. What i really need are the tube lengths and a fin pattern.

The Centuri Egg Crate is exactly the same as the much newer Estes Eggspress except for the Engine mount and fin pattern.

The Estes kit used a single 18mm engine mount. The Enerjet E/F Eggcrate useda 29mm engine mount. The Centuri Egg Crate used a 3x18mm cluster engine mount. The fin pattern can be found attached below or use the link below.

http://forums.rocketshoppe.com/atta...tachmentid=1578

No, you're thinking of the Enerjet Egg Crate. The Centuri Egg Crate was completely different.

Scott;

I thought ST-20 had an OD of 2.04" while BT-70 has an OD of 2.217". That would make BT-70 bigger.

Ya, I meant to say smaller. ;)

I do understand that there is some difference in the tube sizes. I mostly want the fin pattern, and tube lengths would be helpful also. if I have to, I'll just wing it !

I was browsing egg lofters and ran across the Egg Crate (KC-11) in the 71 Centuri catalog - it struck my fancy. A quick search of the forums led me to this thread, but, alas revealed no plans. :p So I took a stab at reproducing the model from the catalog :eek:

Parts list:

Nose cone: Semroc BC-2033
Payload tube: ST-20, 5" length
Transition: Semroc BR-1620F
Sustainer body tube: ST-16, 10.5" length
3 ST-7 or BT-20 motor tube, 2.75" length
3 Semroc TB-7 thrust Blocks
Launch lug: Semroc LL-320
Parachute: Semroc CP-24

Here's the Rocksim 3D image of the rocket:



Rocksim file and fin pattern are attached - would appreciate any comments/corrections

The Mystery of the Egg Crate
 

I won an Ebay auction with parts to the Egg Crate, and they arrived today:



The chute wadding was an unexpected bonus, but the 1970 A5-4 motor caused me to cringe a bit. Priority mail ain't the way to ship those things :p

Measurements are:

Payload tube - ST-20, 5" length
Body tube - ST-16, 12" length (note balsa coupler glued in one end - more on this later)
Nose cone - 2.5" bezier, exact match to Semroc ST-2026

Fins (I will scan and send in patterns on Monday):

Root chord - 3.0"
Tip chord - 1.7813"
Sweep length - 2.2813"
Sweep angle - 45 deg
Semi-span - 2.2813"

Launch lug stand-off:

Root chord - 2.0"
Tip chord - 1.625"
Sweep length - 0.1875"
Sweep angle - 45 deg
Semi-span - 0.1875"

As you can see there are 2 launch lug stand offs on each sheet. I sincerely doubt this puppy uses all four, but suspect it does use two.

I puzzled over the lack of a balsa adapter, and originally thought it had been lost with the instructions, decals, motor tubes, etc. I also could not figure out why there was an ST-16 balsa coupler glued into the body tube and why a paper ST-20 coupler was in the parts. I did some ciphering, and figured out that using a Semroc BR-1620F adapter would put me at least an inch over the rocket length given in the catalog. :confused: I couldn't figure out what was up, and had about decided the length was a typo.

Then it hit me... :o

I went over to the parts section of the 71 catalog, and noticed there was no balsa adapter to connect a ST-16 to an ST-20 - there was only a paper one, the PR-1620, which had a shroud 1 " long.

Mystery solved - I think.

The Egg Crate used a paper shroud - seems kinda crazy for an egg lofter - and part of the ST-16 (over an inch) was used in the construction of the adapter. The balsa coupler was then used to connect the adapter+payload section to the body. Length problem solved.

Does anyone have any instructions to verify the above (and also to tell me if 2 launch lug stand offs were used)? Pretty please? :D

I am planning to clone this, but may make life simple and use a Semroc BR-1620F - at 1.2", it is a little longer than the PR-1620, but a 10.5" body tube would provide a match to the catalog length. That would save the trouble of constructing a paper one, and eliminate the need for a balsa coupler.

Now to work on drawing the decals - looking at the pic on the inside back cover of the 71 Centuri catalog, they consist of a black and red roll pattern, and a couple of lines. Also looks like 2 horizontal strips of silver foil along the egg capsule.

Rocksim file with correct fins and using the BR-1620F attached.