Little Big Joe II - Build

Winter's here...(feels like it anyway) - build time.

One of my favorite kits was the Estes Little Joe II - and having had fun with the Semroc re-release, I decided that I wanted to build something bigger.

I had originally planned for an 11.5 inch dia. project - but that would be rather heavy.

I would like something that I could fly locally on a cluster of BP motors with a central F or G.
I also wanted something a little bigger than Sheri's kit.

But it would have to be light weight...like "ultra" lightweight.
Many years ago I recall seeing a foam core space shuttle in Sport Rocketry...I think it was Matt Steele's.
If I didn't get too crazy with large motors I figured a well designed light weight structure, properly reinforced would handle the flight loads of a cluster of D/Es with a central F/G.

So I set about drawing up plans for the fin framework and a hand rolled 8.5" dia.poster board airframe.

The internal components would be foam core - reinforced with balsa sheet, basswood and in some places, fiberglass.

The airframe corrugations would be fun...I transcribed the details in the scale locations after rolling the airframe on sonotube.

View attachment LBJ -1a- rolled BT on Sonotube.JPG

View attachment LBJ - 2a - detail scribing.JPG

View attachment LBJ - 5a - Fins.JPG

View attachment LBJ - 4aa - Seven motor cluster.JPG

The corrugations (all 120 of them) are done in basswood strip - balsa be would chaper but it would dent too easily.

I reserved areas for the exterior wire tunnels and a hatch for an electronics bay.

The wire tunnels will have conduit for igniter wiring for airstarting the outer ring of motors.

View attachment LBJ - 7a - Airframe Ribs.JPG

I worry about these trailing fins more than any other part on this one..

I laid out a "thru the wall" to the MMT attachment point using plywood plates which attach to the fin LE.
The fun part here was alignment - and getting the fin tabs to dodge all the motor tubes and keep a somewhat scale location of the motors.

This is a dry fit so the parts aren't trued up yet.

I've braced the fin frame with ply where I can..the LE to fin frame needs some more reinforcing.
I'll sheet the entire fin.
Thought about cardboard - but I'll pay the weight penalty and do a thin ply sheeting.

This isn't a transonic rocket ..it is a low/slow "fun fly" kinda thing.

The damage will likely occur on landing, so I'm doing what I can to keep the overall weight/mass low.
Weight at this point is 16 oz. - plus or minus an ounce.

View attachment LBJ - 3a- TTW fins to 38mmt.JPG

Scratchbuilding is rewarding , I particularly enjoy seeing when things in your head, or on paper, turn into something you can look at.

Part of the fun is when you make some progress and things start pulling together, and it starts to look like what you originally envisioned.

Here's a size comparison of the "Big" Little Joe with the Semroc "little" Little Joe II.

View attachment LBJ -6aaa - test fit.JPG

I like it. How did u Cut all of Those basswood strips?

I bought out the local hobby shop supply of 3/32" strip (sorry guys).

I looked over the scale drawings of the Little Joe, and using a scale, a protractor and some basic geometry, came to the conclusion that with some proper spacing, 120 3/32 " wide strips would "close" around the circumference - as long as I traced the rib spacing around the airframe properly, and didn't botch the glue job.

I can feel your pain with those strips!! (remebers the 8-900 on the Saturn!!) I think a blue thunder with some outer Estes motors would look cool in that!!

Yeah...some people are indeed gluttons for punishment.

But - since I didn't find anything in the way of a corrugated wrap that would match the scale size and spacing, and I wanted to get on with it, I figured I better get started - rather than hoping something else would work.

It only took three evenings, a couple of hours each night.

MaxQ said:

Yeah...some people are indeed gluttons for punishment.

But - since I didn't find anything in the way of a corrugated wrap that would match the scale size and spacing, and I wanted to get on with it, I figured I better get started - rather than hoping something else would work.

It only took three evenings a couple, of hours each night.

Click to expand...

well, it looks good!! It was actually going to be one year exactly I picked up the Saturn V from Will when we were going to launch it at Battlepark!! :surprised:

Ben

P.S. just so you know, I will be slowing down in rockets till February. I need to make more solid state relays for my xmas light display and I am making a new controller for 320 + light strings

Nice build. That's some real nice craftsmanship. I also noticed the cant of the outboards in the picture of the motor mount. Will the cant be noticeable during flight?

Thanks...
<"Will the cant be noticeable during flight?>"



Well. I think so.
This isn't as pronounced an angle as you guys with your Dueces...


Honestly, I haven't done a six motor cant before...only two ( 2 E-9's on either side of a 29mm, and it was moving so fast when the outboards lit all I saw was a larger smoke trail when they lit. This one may get the outboards lit on first motion - so I might get a better view, and six flames will be hard to miss.).

ben said:

well, it looks good!! It was actually going to be one year exactly I picked up the Saturn V from Will when we were going to launch it at Battlepark!! :surprised:

Ben

P.S. just so you know, I will be slowing down in rockets till February. I need to make more solid state relays for my xmas light display and I am making a new controller for 320 + light strings

Click to expand...

Hope it isn't another year until you can fly that thing...

So Ben...the lights....is this a tradition?
I've seen some real works of art in Christmas lights...
You have any night launch projects you can transfer this skill to?

I have installed the internal components and I am starting to complete the lower fin can/airframe.

Here are a couple of pictures of the motor mount installation with the fins - installed thru the airframe wall to the central 38mm motor tube.

The only hard part was alignment of the cluster MMTs with the fin tabs...while the glue sets up on the cluster motor mount assembly, a slight rotation was required to ensure the fins will pass thru the airframe wall and seat along the central MMT.
The canted outer ring of motors is intentional.

View attachment LBJ II - Motor mounts installed.JPG

View attachment LBJ II - TTW Fins and MMT.JPG

After applying some epoxy reinforcements along the finroots and the 38mm central MMT - it was time to seal it up with the aft motor mount bulkhead...

First I had to pre-install all the 24mm MMT retentions on the outer ring.

A Giant Leap retention nozzle will be installed on the central MMT.

With that - it was time to move to the hard part..the CSM and LES.

The Apollo capsule is mocked up in a framework with a central 38mm body tube - this assembly will receive a rolled posterboard cone which will be fiberglassed and detailed.

View attachment LBJ II - Aft Motor Mount BLKHead installed.JPG

View attachment LBJ II - Airframe assembled.JPG

Looking awesome so far!

Fun part...

Turning posterboard shrouds and cones for the Little Joe boilerplate capsule, LES nose cone and skirt.

Some rough calculations, dimensioning and scaling, and then some mylar trial and error fitting....

The nose cone for the LES rocket was just pulled off a mold...(two layers of fiberglass on a mylar cone).

The jig for the LES tower is in the foreground.

It's late...

Here's the pic for the preceeding post (.......yawn).

View attachment LBJ II - CSM frame and LES tower jig.JPG

Artwork, that's what that is.

WELL DONE!

I didn't realize you had started a build thread on TRF - well done. Keep up the good work and I can't wait to see it in person.

Thanks.
I figured that I've gotten so much entertainment from this forum over the years that I'd give it a try posting something myself.

Given your building skills ...I thank you for the complement...that means a lot.

If you have any suggestions on the build, or detailing, (esp. on the markings) I'll need them.

Did some work on the tower and LES Rocket last night

Here 's a couple of pictures.
The tower is epoxied wooden dowels...1/4 inch and 3/16 inch diam.

Trim ring for the upper inside tower supports is thin ply. (That was a challenge to cut out by hand.........since I don't have a jigsaw..and it is small)

View attachment LBJ - II LES Tower 1.JPG

The skirt at the base of the LES rocket is a rolled posterboard shroud with a light fiberglass layer over that...and some wood filler.

Once the last tower braces are added inside the structure, it will be time for the LES rocket nozzles.

Then some holes will be drilled in the skirt to receive the tower supports.

I see some trial and error fitting on the CSM coming soon.
Will have some real fun setting the whole thing plumb....

View attachment LBJ II - LES Tower 3.JPG

Weight of all the components at this juncture just tipped the 2 lb. mark.
A bit dissapointing since I'm trying to keep this ultralight.

The strengthening of the load bearing areas - inc.the fin joints, tower joints and internal central core motor which has the recovery system attachment point on it - probably is what raised the total weight so quickly.

Keeping a picture like this in front of me during the build certainly keeps the energy level up when it gets late - or the when the fabrication of many parts starts to get a bit tedious or monotonous....

(Hmmm...how much wood would I need to build that neat launch pad...)

I've completed the major components.

- Little Joe II airframe (fin can and internal cluster motor mounts)
- Apollo Capsule CSM
- Launch Escape System Tower
- Launch Escape System rocket

Now I'll need to proceed with the various detailing items on the components.
-Sheet the four fins
-exterior wire tunnels and spice rings on the fin can
-Capsule Blast cover nose cone and details on the capsule
-LES nozzles

I cut the tower legs long for the jig...they need to be trimmed down on both ends for proper length (shorter).

Here are a few more "in-progress" pictures..........
Weight at this point is still 2 lbs.

Very pretty!

Thanks Juerg.

It's not quite as precise as a Swiss watch.....
You folks in Europe set the bar high for scale projects from what I have seen on the internet.

I have admired the Ariane project - from a distance.

I'm trying to find a compromise between complexity, weight and cost, and my available time to finish a project for spring flying.

MaxQ said:

Thanks Juerg.

It's not quite as precise as a Swiss watch.....
You folks in Europe set the bar high for scale projects from what I have seen on the internet.

Click to expand...

Remember: Pictures are forgiving! (not everything is as pretty on close inspection)
You have no reason to hide, I'd say!
I am currently working on a 1/20 scale Little Joe II as well... or should I say "the partially finished tower is collecting dust" (that's as far as I have got). So that's triggering my attention evidently.

Keep on the nice work

Juerg

Thats a cool looking kit

gerbs4me said:

Thats a cool looking kit

Click to expand...

Kit?

Well, umm...
I hate to tell you this, but........

forgot to keep up with this thread! Can't wait to see it man!!

The lights are sorta a tradition. This is the first year I used the computer to do it so its been a learning experience.

Ben