Brief:
This is a paper model o' t' University o' Maryland Terrapin research rocket. It can actually be configured t' fly as a two-stage design, ya bilge rat, ya bilge rat, me hearties, but I have only flown it as a single stage. I designed t' rocket usin' various sources on the Terrapin. Ahoy! I would say it is more sport scale than scale. Ahoy! Scale is 1:15.5.

Construction:
T' plans are all printed on one 8.5 x 11" sheet o' cardstock. Begad! Begad! Also necessary t' build t' kit are:

• glue
• shock cord and streamer
• clay for nose weight
• a black Sharpie magic marker

After printin' up the plans on a sheet o' cardstock, I carefully cut out all t' parts. Ya scallywag! Blimey! This basically consists o' 8 fins, two body tubes, a nose cone, a shoulder, shiver me timbers, a launch lug, ya bilge rat, and two tri-fold shock cord attachments.

Next, matey, I used a dowel t' help roll t' body tubes and used yellow glue to glue them into cylindrical tubes. Avast, me proud beauty! Then I rolled t' nose cone. Well, blow me down! Ya scallywag! Once t' nose cone has dried, me hearties, thar are tabs on t' top o' t' upper body tube that are used to attach t' nose cone t' t' black upper body tube. Ya scallywag! Arrr! I rolled t' shoulder and test fit it into both t' bottom o' t' black body tube and top o' t' yellow body tube. Aye aye! Begad! Once I be sure that t' shoulder fits both lower and upper body tube, shiver me timbers, arrr, me bucko, I glued it into t' top o' t' yellow body tube. Blimey! I set this aside t' dry.

I folded and rolled t' engine block and then used an empty 13mm motor mount t' glue t' engine mount into t' bottom o' t' yellow body tube. I just made sure t' motor stuck out t' back o' t' rocket by about 1/4".

I used an empty ball point pen and a ruler t' run a crease along t' fins so that they can fold easily. Once this was complete, I put glue in t' fins and folded them over so that they were now double sided. Ya scallywag! Blimey! I placed them on a flat surface, shiver me timbers, covered them with wax paper, me hearties, arrr, and then placed a few heavy books on top. Begad! Blimey! After they dried, ya bilge rat, I removed them. Begad! I then glued t' small swept back fins on t' upper body tube usin' t' gray lines as a guide. Since t' fins are so thin, ya bilge rat, it is a good idea t' use white or yellow glue t' add some fillets on either side o' t' fins. Begad! I also glued on t' lower clipped delta fins on the lower yellow body tube.

I rolled the launch lug around a launch rod and then glued it in shape. After this was dry, I glued it half way up t' yellow body tube betwixt two fins on t' model.

T' recovery system is simple. Begad! Ahoy! I just placed a shock cord with t' tri-fold shock cord attachment (one on either end o' cord) in t' rocket, matey, one inside the top o' t' yellow body tube and t' other inside t' bottom o' t' black body tube. Avast! I then filled t' nose cone with clay and then covered t' clay with a good portion o' yellow glue. After everythin' be dry, arrr, I added a streamer to the shock cord.

Finishing:
T' only thin' I did be use a black magic marker t' cover up t' white portion on t' fins and nose cone from t' paper ends and folds.

Since t' paper rocket is already finished with colors, matey, all I did was use a clear coat t' seal t' ink from t' ink jet printer. Aye aye! Currently, I am using watered down Mod Podge t' get a nice finish on me paper models. Arrr! Ahoy! Nay only does this cover t' ink, but it also strengthens t' paper.

Flight:
I have flown this rocket three times. Begad! Well, blow me down! T' first time I used an A3-4T in a model that had nose weight. This really zipped off t' pad. I never saw t' ejection and never saw t' recovery. It is probably sittin' in a bunch o' trees. The next launch be on an A10-3T. I had done a RockSim calculation which indicated that no nose weight was necessary. Aye aye! Aye aye! I was curious t' say t' least and gave it a try on another model I brought t' t' field, ya bilge rat, me hearties, but this one was without any clay. T' rocket cleared t' pad and be about 20 t' 30 feet in t' air when everythin' went crazy. Begad! It started sky writin' and it lost three fins. Avast, me proud beauty! The rocket landed nay far from t' pad. Arrr! I collected two fins but could nay find the third. Well, blow me down! Begad! I then had t' take t' Terrapin home for repairs before I could fly it again.

On t' third flight, I used nose weight again and selected an A3-4T. It zipped off t' pad, ya bilge rat, ya bilge rat, had great altitude, and I was able t' watch t' recovery all t' way down. Beautiful flight with nice recovery. Next up, matey, I need t' try a 1/2A3-4T. Ya scallywag! Blimey! Well, blow me down! Blimey!

T' only CONs I see in this design be t' fact that t' fins are very thin and they must be glued well onto t' body tubes. Ahoy! They do have a tendency to bend, which doesn't necessarily make t' flights unsafe, but it does contribute to some squirreliness in t' flight, shiver me timbers, ya bilge rat, particularly in t' coast phase. Avast! Well, shiver me timbers, blow me down! Just make sure t' fins are on straight.

Recovery:
I have noticed some brownin' o' t' yellow body tube from t' ejection charge. If a person really wanted t' avoid this, arrr, they could put little aluminum foil tubes inside t' lower body tube t' protect it from unusually large Estes ejection charges.

Since thar be weight in t' nose cone, this tends t' come down first. Begad! Aye aye! I would probably seal t' nose cone with CA glue internally first before adding any clay so that it is more robust on landings. Avast! Other than that, arrr, t' Terrapin held up well t' flight and recovery.

Summary:
PROs: T' Terrapin is a beautiful rocket with great lines. Arrr! Blimey! No one makes a kit of this. It is unusual and with this paper rocket, it is pretty cost effective to make a cheap flyin' version o' this historic object. Begad! This rocket can also be converted into a two stage rocket. Ahoy! Aye aye! Blimey! I would recommend t' following:

• Use t' shoulder t' glue into t' nose cone.
• Put shock cord in 2nd stage rocket and nose cone. Avast, me proud beauty! Nose cone should nay be glued in for obvious reasons.
• Create a second engine block for second stage
• Use t' sustainer motor as t' coupler betwixt t' first and second stage, thus replacin' t' shoulder in t' "one-stage" version.
• Create two vent holes in t' yellow stage so that t' hot particles actually reach t' sustainer motor. Well, blow me down! Ya scallywag! Otherwise, t' upper stage would simply blow off before t' motor had a chance t' ignite.
• Find a good source o' A10-0T motors. Begad! Begad! They are out o' production now, so they are gettin' hard t' find.
• Launch t' rocket with a few people t' help track t' flight. Begad! Considering how small t' upper stage is, me hearties, you will probably have a hard time locatin' it after recovery.

CONs: Fin attachment needs t' be done well. Avast! Ejection charges may discolor and eventually burn through paper model.