Thursday, January 20, 2011

Mega Review: Scale Paper

This post presents four scale paper kit conversions.  A couple fly great, one OK, and one was mainly a curiosity.
  1. Mercury Redstone (Delta-7 Studios)
  2. Little Joe I (Cards in Space)
  3. SpaceShipOne (Currell Graphics)
  4. Airship R-100 (Currell Graphics)

Mercury Redstone

This rocket was based on a free paper model kit from Delta 7 Studios. I converted it to fly on MMX motors, although the model is large enough for up to 18mm motors. Of course, the larger motors may require additional reinforcement that wasn't required in my MMX version.


SPECS: 11.25" x 0.75" - 0.3 oz

The kit includes:
* One sheet of white cardstock
* 7mm tubing ~ 1.5" long
* Hand-cut cardboard centering rings
* 1" piece of an Estes engine spacer tube
* 1" of 1/16" dowel
* Piece of a BiC pen's ink tube
* 4" of Kevlar® twine
* 12" section of plastic marking tape

The parts and instructions each come in a .pdf file. The model includes 19 parts, which you print on a single 8"x 11" sheet of cardstock. The photo-illustrated instructions are three pages long. These are well detailed and are more than adequate for this relatively simple model. I printed the model on cardstock on my OfficeJet and gave it a clear coat for protection.

Construction of the booster is straightforward. The body consists of two wraps that are formed into cylinders and connected together with a coupler. The body is almost exactly BT-20 sized. The fins are each cutout and folded over onto itself so both sides have a printed surfaces. The Mercury capsule, with eight parts, is a little more challenging, but is also easy to construct. The final component is the tower, which has four parts. I built the base paper model entirely with white glue.

Once the paper model was complete, I proceeded with its conversion to a flying model. Since I wanted to use it for MicroMaxx, I wanted to keep the added components to a minimum. If you wanted to use larger motors, more effort would be in order.

The motor mount is a piece of 7mm (T-2+) tubing from Totally Tubular, and two hand-cut card stock rings. Scrap card stock was rolled and used as a motor block. I used a piece of a BiC pen's ink tube for the launch lugs. One is near the center of the model and the other is on the side of a fin. I attached these with Liquid Nails. I had wanted a piece of clear tubing for the nose cone shoulder to keep the base of the capsule visible but I didn't find any, so I used a piece of an Estes 18mm motor spacer tube instead. I elected to glue the tower on, and added a small dowel to stiffen it.

I pondered a full recovery system - shock cord connecting the cone to the body, streamer, etc. However, I decided that this wasn't necessary for low flights on soft-grass. To save my Kevlar®, I decided to let the body tumble and to add a small streamer to the cone so I wouldn't lose it in the grass. The streamer is tied to a short leader of Kevlar® that is epoxied to the inside of the shoulder.

The CG of the model with a MMX-II installed is 6.75" from the top of the escape tower (ignoring the tiny tip).

I added small piece of tape to the motor to keep it in at ejection. You may notice that I didn't add an inside tube or protect the cardstock from the motor ejection. I packed some cellulose wadding into the tube, rolled the streamer and gave it a try. Evidently, this wadding and the spacing between the motor and the body was enough to protect the card stock body.

I have flown this six times so far. On the first flight, I found that I needed the lower lug. The rocket arced over and ejected down range. I added the lug and the next flights have been picture perfect. For such a large MicroMaxx model, I am surprised how high it goes. The capsule was easy to find and the body tumbled without going 'ballistic'. My cheap recovery method was OK after all.

This is a great looking, simple scale model that would be an excellent introduction to paper model conversion. It flew great on MMX-II motors and should adaptable to 13mm or even 18mm motors. If you look around the Delta 7 Studios' site, you will find someone has in fact done so.

Little Joe I

This rocket is based on a paper model of the Little Joe I, unit LJ-1, by Cards in Space. I converted it to fly on 13mm mini motors.


SPECS: 11" x 1.5"

The rocket consists of:
* three sheets of white cardstock
* 13mm tubing, ~5.5"
* 1/8" launch lug
* spent 13mm casing
* thin elastic

The parts and instructions come in a single PDF file. The model includes a lot of parts, many of which I didn't use. For example, I didn't install the 4 engine bells, however, they probably could have been integrated into the flying version. The one page of instruction is bare bones but is adequate to build the model. The penalty for mistakes is only an extra sheet of cardstock.

The main things you have to do is: cut holes in the bulkplates to accommodate a motor ejection tube, build a shoulder to mate the capsule to the body, add a piece of elastic to keep the parts together after ejection (a streamer is optional), and add a launch lug. In fact most of the changes I made were leaving detailing components off.

I used white glue throughout. The body consists of one long wrap and a few rings. A short reducer section rests on top of this. The rings on the bottom end are pre-marked for the 4 engine bells so you have to mark and cut the hole for the motor tube. The designer was good enough to mark the two other rings with a single circle, which I cut out and used as a guide to mark the bottom rings. This was very convenient. A section of 13mm tubing extends the length of the main body.

The four fins each consist of two parts: an outer shell that folds over on itself and a spacer that forms the base of the fins. The capsule consists of a couple of transitions, a cylinder, and two plates. I formed a shoulder by first embedding a section of 13mm tube in capsule through the bottom plate. I then glued in about ½ of a spent 13mm casing. I cut corners big time on the escape tower. This would be by far the most difficult part of the build and the most fragile. The instructions require you to cut out the trellis sections and the tip probe. I didn't cut these sections out, nor did I bother with a the probe. A piece of toothpick would probably be a good substitute for the latter. The way I built it also made it inconvenient to install the escape tower nozzles--so I said adios to these also.

For recovery, I merely attached a short piece of thin tubular elastic. I small streamer could probably be packed in the gap between the top body ring and the capsule, but I was satisfied with tumble recovery.

It is obviously pre-printed, so all you need is a clear coat for protection.

I have flown the rocket 4 times to date, twice each on A10s and A3s. Prep consisted of friction fitting the motor and that's it. Both motors result in nice flights, but the A10 is a better choice in my opinion.

This is a nice looking, simple scale model that is an excellent introduction to paper model conversion. It flies great on the 13mm motors!


October 4th, 2004, heralded a new era in space exploration. On that day, Brian Binnie piloted Scaled Composite's SpaceShipOne to 367,442 feet (112 kilometers), capturing the $10M Ansari X Prize. Later that day, I learned of Currell Graphics' SS1 paper model and immediately wanted to convert one for flight.

Currell offers two versions: the original version and the X1 version that made the two historic X Prize flights. I chose the latter. Prior to building the model, I opted to convert it for MicroMaxx motors. As you will read, this model is a bit too big to be a great flier on these small motors but shows promise for a 13mm conversion.


SPECS: 7" x 1.25" - 0.64 oz

Items needed:
* 3 sheets of white cardstock
* ~6" of Totally Tubular T-2+ tubing
* ~1" of Totally Tubular T-2 tubing
* 1 6mm--10.5mm centering ring
* Clay and lead shot
* Piece of a BiC pen ink tube
* Kevlar® twine

The instructions for the SS1 are five pages long and include a bit of history, some narrative, and an excellent set of illustrated directions. This is one of the most complex paper models that I have ever built. It includes over 85 parts, many of which are quite tiny. Being that I am not a stickler for detail, not to mention "all thumbs", there were around 30 parts that I didn't use. Many of these were for the "gear down" option.

The most important tool required is a new hobby blade. I also used a cutting mat, scissors, a couple of toothpicks, and some small clamps. I built it mostly with white glue but used Perfect Glue to tack down the Kevlar® twine and attach the plastic lug.

Nosecone (a.k.a. front fuselage) - This section spans two steps and requires around 14 parts. It is comprised of several cones/transitions with center bulkheads, which come in pairs. Since I thought I would eventually need nose weight, I filled the small tip with clay. I cut holes in the bulkheads A9--A12 to accommodate the 6mm tube. I also replaced the smallest bulkheads, A7 and A8, with a 6mm--10.5mm fiber centering ring. I could have cut these bulkheads, but they are tiny. A 1.75" piece of 6mm tube extends from the clay to just past the last transition. You need to make sure it doesn't stick out too far lest it interfere with the bulkhead in the next section. I inserted a piece of T2 tubing (which telescopes into the T2+) to form a shoulder. This was not glued in. The nosecone assembly can be seen in the first photo.

Body (mid- and tail sections) - This section consists of more paper transitions and bulkheads. It spans steps 3, 5, 9, and 19 and consists of around 15 parts. Steps 4, 6, 7, and 8 are all related to the landing gear option and I didn't need these for a flying model. As you can see, I also jumped ahead in the instructions to complete the body in one stretch. The first photo also shows the partially completed body section.

Again, I cut holes in all the bulkheads. The motor tube extends from the nozzle to just above the top bulkhead. I cut this tube to fit by installing the nose and pushing the lower tube up until it seated on the nose assembly's shoulder (the T2 tube). I then marked its location and glued it in. When installed, the nose assembly seats against the glue tabs that extend out of the mid-body. I had anticipated removing these tabs and adding solid neck, but this wasn't required.

Main wings - These wings each consist of eight components and their construction//installation spans four steps. All the wings on this model are constructed using ribs/spars and outer shells so they are reasonably complex. The subtle angles and bends on these components are truly impressive. Be wary of too using too much glue, as it will warp the small pieces quite badly (not a theoretical observation). I had trouble getting all the small components together nicely, and even ended up leaving the thin trailing edge strip off. I'm sure many of you can and will do better.

The wings slide onto two spars that you previously install through the body of the SS1. When building the wings, make sure the holes for the spars are aligned and are big enough! No theory here either.

Side booms (the vertical wings that extend toward the rear of the bird) - These have 7 parts each, cover three steps, and are both smaller and more tricky to assemble than the main wings. They are built-up from 2 spars, 2 inner surfaces, and 2 outer wraps. One of the spars is 7 ½" long, has 16 bends, and circles the edge of the wing assembly. My side booms came out pretty rough. They attach to the rear half of the main wings and a small printed component covers the front half.

Stabilizers - These are a lot simpler than their bigger cousins are. They consist of 4 pieces and are installed in 2 steps. Even I got them right.

The last 2 steps of the instructions is detailing that I left off. All I had left to do was to attach the lug (piece of a pen's ink tube) to the underside of the wing, install the Kevlar® twine, and add nose weight. Curiously, the "finishing touches" didn't require any finishing since the model is pre-printed. I didn't even shoot on a clear coat to protect the ink, although this is a good idea if you will fly in damp conditions.

Stability - Micromeister (from TRF and the MicroMaxRockets Yahoo group) graciously provided the CG for his successful MMX SS1 (plans are available on the Yahoo group). I scaled that CG (1.09375") to this larger model (64.8mm), and headed to the Dungeon to install nose weight. After adding ~4g of shot, the total vehicle weight was 18g and I had only moved the CG about half the distance I needed to. As this was pushing the max weight for a MMX-II motor, I decided to give it a try as is.

I flew it three times and each profile was about the same: slow boost, arcing flight, ejection just before "landing". Apogee was estimated to be 10', 6' and 10', respectively. On the last flight, the Kevlar® broke free from the body, which was easily repairable. Note that I do not endorse my positioning of the CG. This model could very well have been unstable had the flight been higher and longer in duration.

This is a very detailed and small model. Despite excellent instructions, I found it difficult to build. You definitely need a sharp knife, good light, a steady hand, and patience.

The flight conversion was straightforward, but the model, once properly balanced, is too heavy to be a great candidate for MMX. I offer these suggestions based on my experience:

1. Add the lead shot at the very tip. I had filled it with clay. I managed to remove some, but still had most of the weight a bit further aft.
2. Look at reducing weight while keeping the basic paper kit.
3. Consider a 13mm conversion. I am happy to say that my original review inspired another EMRR reader to try this. He has logged (on EMRR) around 10 flights on A3-4's and A10-3's. Not bad for free paper.
12/04 - "Thanks for posting this excellent review! You inspired me to build a 13mm version. I coated the wing and stabilizer spars with some finishing epoxy to strengthen them. For my first paper kit, it came out rough but I am well pleased with it. The body seems pretty durable and I should get many more flights out of it. It flies great, much better than I expected. My wife was happy it was free!" (J.T.L.)
P.S. I have posted several reviews of builds that either weren't executed well or that were executed fine but flew poorly. These rockets generally had attributes that I found interesting or, as in this case, could inspire and lead others to do better. The SpaceShipOne review has vindicated these reviews!

Airship R-100

SPECS: 11" x 2.25" - ~0.5 oz

The Currell Airship R-100 dirigible is a detailed 1/700-scale replica of a historic airship built by the British government circa 1930. I’ll warn you that this was not the most successful conversion. I jumped in without adequate planning, so the reader may not want to build it as I did.


Parts List:
1. Four sheets of white card-stock
2. Thin clear plastic for extended fins
3. Apogee 13mm phenolic tube,
4. 1 5/8-inch long 13mm-18mm centering ring
5. Thin plastic 6mm tube from a pen (motor mount)
6. 1/8-inch section of spent MMX motor
7. Hand cut cardboard centering rings ~8mm-13mm.
8. Piece of a BiC pen’s ink tube

The instructions for the Airship R-100 are provided in a .pdf file. They are three pages long and include very understandable schematic assembly drawings. The plans themselves are four pages long and all the parts are keyed to the assembly drawings. I chose the colored versions to print on white card-stock. A line drawing version is also available if you want to print the plans on colored or metalized paper.

The model is very detailed and many of the trim components are very tiny. There are 56 parts to cut out, including a display stand. (if you really are a masochist you can build Currell’s scale mooring tower). I built the model in my lap while watching the boob tube and decided to skip the details (engines, control car). They were just too small. My first tip if you want to build this model (for flight or static) is: work on a good surface in good lighting. Overall, I had a hard time assembling the body. I really needed to have a work bench surface. The precision of my cuts was not good enough to get a perfect fit in the components. In some places, I used scissors whereas an X-acto knife and cutting pad should have been used throughout.

The body is comprised of seven conical sections supported by bulkheads. Each bulkhead consists of two cutouts. I cut 13mm holes in each bulkhead assembly to accommodate a full-length tube. One point is not clear without reading the text of the instructions. Many of the components require that you score the paper with an X-acto knife to ensure precise bends. For example, the body wraps and bulkheads are all 16-sides structures, which must be scored in order for them to conform properly. The nose consists of an additional three conical sections and the tail is one cone. On the latter, I cut the end portion off to accommodate the tube.

The fins are normally made from two cutouts folded over on themselves, so the final fins are four layers thick. However, I knew I needed a lot more fin area for a stable model. Therefore, I built clear fins from some thin packaging plastic, and overlaid the decorated printed fins over these for show. I used the provided paper parts as a template to get the contour and through the wall tabs right. The entire model was built with white glue, except for the plastic fins, which are held on with Liquid Nails.

I had planned to use tumble recovery with a 13mm motor, probably an A10. However, I found that, even with the larger fins, some nose weight would be required. This would make the rocket too heavy (i.e. lawn dart recovery) so I punted and built a MMX adapter.

The adapter is a short piece of 13mm tube just long enough to pass through the first bulkhead. A 13mm-18mm centering ring acts as a thrust ring. I used a section of a thin walled plastic pen for the motor tube and glued in a piece of a spent motor as a block. I hand cut centering rings from two cardboard circles that popped out of an Estes centering ring set that came in a Designers Special. I used Liquid Nails to bond to the plastic, and carpenter’s glue elsewhere on the adapter.

No finishing is required as the hull of the model is pre-printed. I used a clear coat to protect the printing.

This is a huge model for MicroMaxx and I knew the MMX-II motor would be underpowered. I removed the ejection charge from the motor and wrapped some tape on the motor adapter so it was just a little snug. The Airship R-100 lobbed to a whopping 12 feet or so and fell to a soft landing. Another member of my fleet suitable for front yard launches. I flew it once more with MicroMaxx power but finally decided to up the ante and try an A10-P. I made a 13mm mount scrounged from my Paul Miller box-o-dead-rockets. Ignition was oddly late and the boost was a huge corkscrew. Tumble recovery was actually lawn dart recovery. While the model was light enough to recover from 12' without damage, the much higher flight warranted a recovery system.

This is a nice kit if you like paper models, although it is actually a lot more difficult than your typical 3/4FNC rocket. The detailing is great. Here is what I would do to make it a better conversion:

1. Cut all bulkheads for a 18mm tube and use A or B motors.
2. Create a nose cone by splitting the kit near the front. This will require replicating a pair of bulkheads. I would mount a section of tube in the nose cone add a 18mm coupler to mate with the main tube.
3. Add nose weight as required.