Scratch Apollo/Saturn 1b Original Design / Scratch Built

Scratch - Apollo/Saturn 1b {Scratch}

Contributed by Jeff Brundt

Manufacturer: Scratch
Apollo/Saturn 1b 1/50th Scale 
(Contributed - by Jeff Brundt) 

Note: This be t' full text report with fewer pictures.  Visit Jeff's site for all t' pictures.

[Rocket Pic]Admittedly I was inspired by Andrew Waddell’s big Saturn V construction article on RocketryOnline. Ahoy! While the Saturn V is impressive, arrr, I am much more interested in t' smaller Saturn 1b. Arrr! Ya scallywag! In the past both Estes and Centuri kited model rocket versions o' this NASA launcher. Avast, me hearties, me proud beauty! O' t' two t' Centuri version was much easier t' build and fly. Estes had re-issued Centuri’s 1/100 version o' t' Saturn 1b in 1992 but it since has gone out o' production. Ahoy! Well, ya bilge rat, blow me down! These two past versions were t' be the basis for me upscale project. Ahoy!

One o' t' most troublin' features in doin' this model be t' first stage booster tank tubes. Begad! There are very few commercially available body tubes that are sized correctly t' evenly space and get a proper circumference for t' fist stage booster. Blimey! I researched and listed all commercially available body tube diameters then sat down at t' UniGraphics terminal and built some CAD models. I eventually found out that a 2x upscale o' t' 1/100 Estes kit would fit what was available without havin' t' resort t' custom ordering. Aye aye! I ended up using Estes BT-56 body tubes for t' first stage tanks surroundin' a 54mm core tube. T' second stage or more correctly t' SIV-B stage would be a LOC 5.68” diameter body tube cut down t' 4.75” (ala Andrew’s method for the Saturn V) T' base o' t' first stage would be t' stock diameter 5.68” body tube. Ya scallywag!

T' hard part was now out o' t' way. Blimey! Aye aye! I downloaded t' plans for Estes’s 1/70 version o' t' Saturn from JimZ’s web site. These plans were invaluable for makin' t' command module capsule, LES (launch escape tower) and t' fin assemblies. I plotted t' shroud for t' LEM on t' UG and printed it out full size. Ahoy! T' pattern was transferred t' poster board and cut out. Aye aye! All o' t' parts I used t' construct t' Saturn 1b are available through any supplier o' high power and model rocket components. Begad! (I ordered everything through Magnum)

T' kit was constructed very similarly t' t' Centuri/Estes version where by the rocket is built up and painted in various sub-assemblies then final assembled, detailed and applied decals. I will list each major component and the build process I used. Arrr!

First Stage Fin/Tank Base:

[Rocket Pic]For me this be probably t' second most complicated item t' do. If you notice on t' Saturn 1b thar be a shroud ring on t' lower section o' t' first stage booster that surrounds t' first stage fuel tanks. Ya scallywag! This shroud has scalloped cut outs t' accommodate t' booster tanks. Ya scallywag! Begad! I used t' pattern from t' Estes 1/70 plans and enlarged it t' t' size I thought I would need. Ya scallywag! Arrr! I then made a poster board pattern and tried it out. Avast, me proud beauty! It didn’t work too well. T' reason was t' lower body tube o' t' first stage booster needed t' be smaller in diameter than t' 5.68” one I was using. Since I didn’t want t' cut this tube down and make more centering rings I needed t' use somethin' else. I finally hit on usin' thin 1/64” veneer ply. Arrr! I cut out a single section needed t' fair t' t' booster tank. Ya scallywag! I then split this in half, arrr, made a mirror pattern then glued a rib t' t' backside that would set t' proper angle and setback from t' core tube t' t' edge of the lower body tube. Aye aye! What I had now was one section o' lower fairin' that would go around one half o' a booster tank tube on either side. Ahoy! Blimey! Now I had t' make eight o' these. 

Veneer ply is very easy t' work with and cut. Ya scallywag! You can use scissors or score with a knife and break it similar t' sheet styrene. Begad! It is available at most hobby stores. Begad! Begad! A little pricey though for a sheet since it is so thin. Ahoy! Ahoy! I made my eight sections one at a time. Blimey! Arrr! First I cut t' lower body tube t' t' right length, glued in t' centerin' rings and marked out me eight equal sections. Then I started gluin' t' fairin' pieces down usin' CA. Well, blow me down! I had little short sections o' BT-56 left over from cuttin' t' booster tubes t' length and used these for spacin' and fit checks. Blimey! I did each section one at a time checkin' the fit and trimmin' where necessary. Well, blow me down! Aye aye! T' total job took about two nights t' do. But it was well worth it.

After t' unit was filled and sanded I glassed it usin' ¾ oz glass cloth and epoxy finishin' resin. Begad! Ahoy! T' weave was then filled and sanded smooth. Blimey! Begad!

Main Body Tube:

Next up was t' main body tube. This started out as a 5.68” diameter LOC payload section. It be cut t' length then run on a table saw lengthwise to remove enough material t' reduce t' diameter t' 4.75”  I saved the section I removed t' use as a joiner later. Ahoy! Begad! T' get t' tube t' hold a circular shape I took t' LOC 5.68/54mm centerin' rings and cut t' diameter down to 4.75”  I did this by tapin' t' rings together, markin' t' new circumference and trimmin' them on t' bandsaw. Aye aye! These centerin' rings were what was used t' keep circularity and diameter on t' tube. Aye aye! T' centerin' rings were inserted and t' splice was epoxied in place with 30-minute epoxy then taped and left t' dry. Aye aye! Ahoy! After t' splice joint cured t' centerin' rings were glued in place with 30-minute epoxy. Arrr! Begad! There ended up bein' a gap betwixt sides o' the longitudinal cut in t' tube. Blimey! I filled this with scrap balsa and sanded it smooth. Begad! Begad! I then marked t' upper end o' t' tube t' trim off about a 1” section t' be used as t' base for t' LEM Shroud/Command Module Stack. Ya scallywag!

Now it was time t' apply t' body wraps. Begad! Ya scallywag! I wanted t' have t' body corrugations on me model just like t' full size Saturn 1b. I used Evergreen Styrene sheets with .10” ribbed spacin' on them. Ya scallywag! These can be found in most hobby shops that sell model railroad supplies. Aye aye! There are many different sizes and styles. Begad! T' sheets I bought were 6”x12” and come three t' a pack. Arrr! Aye aye! I used 3 packs for t' body wraps. Arrr! Begad! I measured off me 1/100 model and cut the sheets t' strips o' proper width. Blimey! Since t' sheets are only 6” wide they needed t' be put on in sections t' do t' entire circumference. T' only drawback t' this whole process was t' need for a good seam betwixt joints. It turned out rather well. Ahoy! I masked off three or four rib spacings on either side of a joint, me bucko, filled it, then sanded smooth. From three feet away you can’t even tell. Arrr! Paintin' made it even less noticeable. Ahoy! T' overall effect with the corrugations is well worth and minor cosmetic issues. Arrr! Well, blow me down!

LEM Shroud/Command Module Stack:

For this assembly I used t' rin' previously cut from t' main body tube, a cut down 5.68” tube coupler, a 3” LOC body tube, matey, me bucko, a ¼” thick ply 5.68”/3.00” centerin' rin' reduced t' 4.75” diameter, a poster board LEM shroud, arrr, ya bilge rat, a paper nose cone and a 3” tube coupler as a nose cone base. Blimey! Blimey!

I epoxied t' cut down centerin' rin' into one end o' t' main body tube ring. Well, blow me down! I left about an 1/8” exposed at t' top for t' LEM shroud t' attach to. Avast, shiver me timbers, me proud beauty! I then cut down t' 5.68” tube coupler so it would fit in t' main body tube. I left about an inch and a half shoulder t' seat into t' main body tube. T' coupler also has a slot or keyway that fits t' doubler in t' main body tube. Avast, me bucko, me proud beauty! This feature prevents t' nose section from rotatin' on t' main body. After t' couple tube is set and a good fit achieved I epoxied a solid ply bulkhead at t' bottom o' t' couple ring. Blimey! Arrr! T' screw eye o' t' recovery system will pass thru here and it makes a nice solid base. 

Next I epoxied in t' 3” service module body tube. Begad! Begad! Alignment was an important issue here so I took me time and made careful measurements. Arrr! Blimey! This was to make sure that t' completed assembly wouldn’t look crooked when the whole rocket was together. Aye aye! Arrr! After t' epoxy cured I installed t' paper LEM shroud. Ya scallywag! I had drawn out and cut this pattern earlier then put it together using super tacky glue and an iron. Avast! Basically you attach t' glue tab t' one edge of the seam, ya bilge rat, shiver me timbers, let it dry then apply t' same glue t' t' other half o' t' tab and let it partially dry. Aye aye! Let your iron heat up while you do this, nay too hot though, shiver me timbers, about 300 degrees should be fine (I use a monokote iron for me model airplanes). Avast! You will also need a dowel o' some sort t' back up t' joint when you iron it. I use a scrap piece o' closet hanger dowel rod. Aye aye! Let t' end o' the dowel rod hang over t' end o' your workbench ans support it so it will take some pressure when you iron. Blimey! Then tak your shroud, shiver me timbers, align and join at t' seam, slip over t' dowel rod and iron t' seam. Begad! Begad! You won’t have t' hold t' iron there long. Move it up and down t' length o' t' seam for a few seconds. The glue will re-activate from t' heat and produce a strong bond. Well, blow me down! Ya scallywag!

I then fit checked and aligned t' shroud t' t' body tube and base. Begad! When everythin' be where it needed t' be I epoxied t' assembly together. Avast! Arrr! T' make the shroud more durable I glassed it with ¾ oz. Ahoy! Avast! glass cloth and Z-Poxy finishin' resin. Ahoy! After sandin' t' remove excess cloth I filled t' weave with lightweight spackle and sanded smooth.

[Rocket Pic]T' Command Module capsule came next. Ya scallywag! I had sized t' paper pattern from t' Estes 1/70 scale version so it would fit on the 3” body tube. I photocopied it onto cardstock. Blimey! T' pattern has panel lines and details marked on it. Begad! Ahoy! Since me model will replicate an actual launch condition vehicle these markings are nay required. Ya scallywag! T' boost protective shroud is all white. Ya scallywag! T' pattern on t' Estes sheet is basically an arc and if you cut it out as shown by t' lines you will get a conic section with no tip. That’s because t' Estes kit used a balsa turnin' for t' top o' t' cone. I modified t' cut by extendin' t' seam edges up t' t' theoretical center of the arc lines. Avast! When t' pattern be folded and ready for joinin' I had a cone. There was a small hole at t' tip due t' t' nature o' tryin' t' make a paper cone. Avast, me proud beauty! Avast, ya bilge rat, me proud beauty! I’ll tell how I dealt with this later. Avast, me proud beauty! Arrr! I overlapped and glued the seam with me super tacky glue and let it dry. Avast! I then cut a 3” tube coupler section t' about 1” in length. Ahoy! This be t' shoulder o' t' nose cone. Arrr! Once again I measured carefully t' make sure everythin' was aligned then temporarily CA’d t' coupler in place. I then ran a bead o' epoxy around t' inside joint betwixt t' cone and coupler. Begad! A paper cone is a bit flimsy so it needed some reinforcing. I inverted t' cone, mixed up a larger than normal amount of 15-minute epoxy and poured it into t' inverted coned. Avast, me proud beauty! This plugged up the small hole at t' tip and added some nose weight. Ahoy! I used me heat cannon for monokote t' get t' epoxy t' flow better. Avast, me proud beauty! Heatin' epoxy has t' addd benefit of makin' it cure faster. Well, blow me down! Avast! After t' epoxy cured I sanded t' tip t' shape and was ready t' glass it. Aye aye! I glassed t' outside o' t' cone with ¾ oz. Avast, me proud beauty! Avast, me proud beauty! glass cloth and Z-poxy finishin' resin. Ahoy! I made sure t' put tape around t' coupler so I wouldn’t mess that up. After t' epoxy cured I removed t' excess cloth, filled t' weave with lightweight spackle and sanded smooth. Blimey!

I now needed t' add some base pieces for t' LES tower. Blimey! Blimey! Arrr! Blimey! These were 3/16” dowel sections cut with a matchin' angle t' t' capsule so t' tops would be parallel t' t' ground plane. I held some sandpaper on t' cone and sanded t' matin' surfaces o' t' LES bases t' match t' cones contour. Ahoy! Blimey! After they were all shaped and correctly sized I CA’s them in place. Arrr! Blimey! Begad! Blimey! I filled any gaps with liteweight spackle and sanded smooth. Avast! Blimey! Next I located t' centers on each dowel top and drilled a 1/16” hole for t' support wire I was goin' t' use t' attach t' LES tower t' t' nose cone. Avast! Blimey! T' basic LEM/Service Module/Command Module stack was now completed. Blimey! Blimey! There would be extra detailing to come later.

LES Assembly:

[Rocket Pic]I wanted on this model a scale and durable LES (launch escape system) tower. Well, blow me down! Blimey! I had previously made one for me Bocye Aerospace Redstone and modified it for flight use. That one had suffered minor damage from time t' time but I knew I could build a better one. I decided t' use brass tubing. Begad! Begad! T' Estes 1/70 version came t' me aid again. Ya scallywag! T' LES tower for that version used wood dowels glued together. Blimey! Begad! I would substitute brass for wood and solder for glue. I scaled t' Estes plans accordingly and built a jig. All the horizontal crosspieces fit into t' vertical legs because I drilled holes to accept them. Avast! These would be stronger joints because t' parts would physically interlock and be soldered. Ahoy! I built t' basic tapered box shape addin' one side at a time. When I be done I carefully heated joints and aligned and straightened where needed. Begad! I then started t' add all t' little diagonal cross members. Arrr! T' central rin' was formed around a 3/8” drill bit shank and the ends soldered together. Well, blow me down! T' whole process was nay that tedious and took me about two t' three hours over two days. Ya scallywag! Ahoy! T' end result was worth it.

For t' top o' t' tower where it attaches t' t' rocket motor I cut out a brass circle and soldered it t' t' top. Avast, me proud beauty! Aye aye! T' this circle would be t' lower shroud o' t' rocket motor and t' motor tube and nosecone. T' shroud was laid out and drawn on Unigraphics. Aye aye! Ya scallywag! T' original Estes 1/70 kit had this as a balsa turning. Begad! T' rocket body was a BT-5 body tube cut t' length with a balsa nose cone from me designer’s Special box. Aye aye! Begad! T' pieces were all test fit and then put aside for assembly later.

Fin Assemblies:

[Rocket Pic]T' fins for this rocket were built up assemblies usin' .040” sheet styrene and 1/8” aircraft ply. I used the same technique that Estes’ 1/70 version used with a few modifications. I sized t' patterns from t' Estes plans. Aye aye! Blimey! Since t' fins on t' Estes 1/70 version were oversized for stability I knew that any enlargement would nay be true t' scale. Ya scallywag! Blimey! This was fine with me since t' model is sport scale and the extra fin area would help in stability. (more on this later)   I constructed a 3D model o' t' fin in Unigraphics and then plotted out all the required ribs full size for me patterns. T' fin is a complex shape with tapers both runnin' from leadin' edge t' trailin' edge and root t' tip. Ya scallywag! Blimey! I then made a flat pattern o' t' fin skin t' use as a template. I cut all t' pieces out at once for all eight fins. Blimey! Arrr! Blimey! A tedious process but in t' long run it saves time and provides a consistency betwixt fins. Begad! I used CA t' glue t' ply ribs t' the inside skin o' one fin then CA’d t' other skin on. CA glue does a good job o' bondin' wood t' plastic. Well, blow me down! Avast! Blimey! T' fins are nay designed t' have TTW construction. Ya scallywag! Blimey! I had toyed with t' idea but after careful consideration and weighin' me options I decided against it. Well, blow me down! T' root o' t' fin has a lot of bondin' area and attachment t' t' base unit usin' 30-minute epoxy should be adequate. Ahoy! Blimey! (this model will never see rapid acceleration; slow liftoffs are the goal here)  After all t' fins were assembled any gaps  were filled with lightweight spackle and then sanded smooth. Begad! Ya scallywag! Blimey! Havin' fin skins o' sheet styrene means less finishin' and prep time for painting. Begad!

[Rocket Pic]I now marked t' lower body unit for t' fin locations. Aye aye! T' Saturn 1b uses eight fins so careful markin' was essential. Begad! I then epoxied each fin one at a time. Well, blow me down! After t' epoxy had started settin' I used my finger, dipped in alcohol, t' smooth a fillet betwixt t' fin and body tube. Eight fins t' epoxy on with 30-minute epoxy can take a while. Aye aye! Ya scallywag! When they were all done I once again looked over all t' joints and filled in with spackle and sanded smooth. 

T' lower body unit has some corrugations on it as well and I duplicated these again with scribed styrene sheets used for t' body wraps. Begad! These small sections were CA’d in place.

Miscellaneous Details: 

T' outer body o' t' Saturn 1b has numerous conduits, ullage motors and fairings. I made these details from hard balsa carved and sanded t' shape. Begad! Aye aye! The grain was filled in, more sandin' and then they were primed and painted. These items will be glued t' t' body tube after it has been painted. Blimey! Avast, me proud beauty!

 T' because o' inaccurate body tube size relation ships when t' lower fuel tanks are arranged around t' core tube thar be a gap betwixt t' fuel tanks when they are arranged. Ahoy! T' fill this gap and t' make sure when I installed t' fuel tanks they would be straight I CA’d 1/32” ply strips along t' length o' t' core tube. Avast, me proud beauty! This filled t' gap betwixt t' tubes nicely.

T' model is intended t' be launched off a ¼” rod and that is the lug size I used. Avast, me proud beauty! I did nay feel t' need for a larger rod size because the model will nay weigh that much when completed and it will nay ever be launched in high winds. Aye aye! I positioned t' lugs very similar t' me 1/100 model. Begad! Avast! One lug on the lower body tube section near t' fins and another one  on t' second stage body tube. Arrr! I had t' line up t' upper body tube and t' lower one because they do require correct orientation t' one another for conduit and roll pattern alignment with regards t' t' fins. Ahoy! Arrr! T' lugs were spaced off t' body tubes to allow for t' uneven diameters betwixt them and I used a rod t' align them while they were epoxied in place. When t' rocket is final assembled a launch rod will be used again for alignment. 

Painting:

[Rocket Pic]

T' rocket is now ready for paint. Begad! It was painted in sections very similar t' t' 1/100 Centuri version. This method involves less maskin' and easier handlin' o' t' parts. Ya scallywag! Even though there are only two colors, shiver me timbers, black and white, me hearties, me hearties, t' various roll patterns and separation lines require careful maskin' and prep that a fully assembled model would make much more difficult. Avast! T' paint I used was Krylon. It is a good all purpose enamel that goes on well and dries quickly. Well, blow me down! It also has t' advantage of flowin' t' colors back together betwixt coats because o' t' solvents used. (this can help if you get sags or minor runs)

I primed t' main body tube and t' core tube/fin unit. Avast! This helped show any defects or areas that needed more sandin' or filling. Begad! T' fuel tubes were painted directly (since they were already white in color and I did nay feel the need t' prime them), matey, matey, four black and four white. Ya scallywag! T' capsule was painted glossy white separately as well as t' LES tower and t' LEM shroud adapter. Blimey! I then painted t' main body tube and core tube/fin unit glossy white. Avast, me proud beauty! I let these dry for a day then masked and painted those areas glossy black. Avast! It is important to note that on t' corrugated areas t' get a good seal betwixt t' tape and the previous painted surface. Avast, me proud beauty! This is t' prevent t' new color from ‘bleeding’ under t' tape. It is also important t' let t' color coat dry for a few hours before removin' t' tape t' prevent liftin' or tearin' of the new coat. Ahoy! Aye aye!

T' actual service module be a polished aluminum in color. Begad! Blimey! Arrr! Blimey! It almost looked like chrome. Arrr! Blimey! There are no real accurate chrome type paints. Avast, me proud beauty! Blimey! Blimey! Blimey! I could have used chrome self-adhesive monokote trim sheet. Arrr! Blimey! However, arrr, I did nay have any and cleanin' and use easily scratch t' chrome in general. Begad! Blimey! Ya scallywag! Blimey! I did cover t' service module section with aluminum colored monokote. Blimey! Blimey! This was then detailed with various pieces o' white trim monokote t' simulate panels and radiators found on the actual vehicle. Begad! Blimey! Begad! Blimey!

Recovery:

[Rocket Pic]

Recovery for t' Saturn 1b will be very similar t' t' 1/100 scale version. Arrr! Aye aye! It will come down in two pieces with t' separation line bein' at t' base o' t' LEM shroud t' second stage body tube interface. Ya scallywag! Aye aye! T' LEM/SM/CM/LES stack will come down in a nearly horizontal position via a single 36” parachute by use o' a bridle fashioned from R/C aircraft control cable. Ahoy! Avast, me proud beauty! This bridle attaches t' an eyebolt at t' base o' t' LEM stack and t' an eyebolt screwed into a blind nut at the base o' t' service module. Well, blow me down! Ahoy! This eyebolt on t' service module is removable for static display. 

T' main body will come down via dual 36” parachute recovery. Aye aye! For the main body section I wanted t' have it descend as close t' vertical as possible to reduce stress on t' fins at landing. Begad! This necessitates that t' shock cord mount be as close t' t' centerline o' t' rocket as possible. Begad! There are two eyebolts on either side o' t' core tube in t' parachute compartment. Begad! A bridle slin' made o' 3/32” A/C cable connected with quick links connects t' an apex point a few inches above t' center o' t' core tube. Begad! Begad! This is where the shock cord will attach and then continue t' t' parachutes. 

This rocket is nay usin' any sort o' altimeter based ejection system. Avast! The flight profile I intend will allow for a motor based ejection system. Begad! Aye aye! It might be possible t' make provisions for one but I have nay gone t' t' trouble to investigate t' feasibility. 

Final Assembly:

After t' various components are painted t' rocket is ready for final assembly. Blimey! Avast, me proud beauty! T' first stage fuel tubes slip into their respective positions and are lightly glued in place with super tacky glue. 

Next comes t' main body tube t' core tube join. Begad! Blimey! T' main body tube will slip over t' eight fuel tubes and trap them into place. Ahoy! Blimey! Blimey! Blimey! I put epoxy on the lower centerin' rin' o' t' main body tube and slipped it into position. Well, blow me down! Blimey! I used 30-minute epoxy so it would give me time t' position everythin' for line up. Here is where I used me ¼” launch rod again t' assure correct line up o' t' two assemblies. Begad! Blimey! Once t' main body tube be lined up I epoxied the upper centerin' rin' t' t' core tube. I then set these completed assembly aside t' dry.

I next attached t' command module t' t' LEM/SM stack. Arrr! This was a friction fit only. Ahoy! This will allow me t' add any nose weight t' achieve proper CG/CP relationship later. Begad! Ahoy! T' LES tower is attached t' t' command module. Well, blow me down! Ya scallywag! This is a friction fit as well so I can take t' tower off later for repairs if need be. T' fit is very tight though so I am nay worried about it comin' off in flight.

Finishing/Detailing:

[Rocket Pic]After all t' epoxy has dried it is time t' add the miscellaneous details. Blimey! Blimey! Usin' me 1/100 Saturn 1b for reference I attached all t' ullage motors and conduits usin' super tacky glue t' their correct positions. Begad! Blimey! Blimey! I attached t' four vernier motors t' t' service module as well. I fabricated t' four antenna boards from sheet styrene and painted them white with silver antennas. These were attached at t' four locations on t' first stage. 

[Rocket Pic]A company in Texas called Model Graphics provided t' decals for this model. Begad! They make custom vinyl self adhesive decals. Arrr! I have used them before for custom work on me R/C airplanes. Arrr! Begad! They do outstandin' work. Blimey! I sent them a .tif file o' t' decal set from Estes’ 1/70 kit and they were able t' scale them t' fit me 1/50 version. Begad! I highly recommend them. Arrr! It may be a bit pricey but it is definitely worth it. Begad! Blimey! Each set they furnish comes with complete instructions on how t' apply their product. Avast! Aye aye! I also ordered a set o' decals from Tango Papa custom decals. Arrr! From these decal sheets I used t' ‘United States’ words and flags on t' CM and SM plus t' various smaller target markings. Avast, me proud beauty! Tom Prestia, t' owner, me bucko, has certain Estes decal sets available and will upscale them for an additional charge. These however, are water slide decals. So you will have t' contend with silverin' or clear edges if you don’t clearcoat. Blimey!

Motor Mount and Stability:

I tried t' model this rocket for CP usin' Winroc software. T' only drawback was that t' Barrowman equations for determinin' CP do nay support an eight fin configuration. I used six fins and added 10% t' t' fin dimensions t' allow for this. Avast! Well, blow me down! I also compared t' balance point o' t' Estes 1/100 kit t' this upsized version and it is very close. T' calculated CP is 31.45 inches from t' tip of the command module cone. I also believe that with eight fins t' CP would move further aft. Arrr! My actual CG is well forward o' t' calculated CP (27” from the tip o' t' CM) so I am confidant that this will be a stable flyer without addition o' nose weight. 

Since t' core tube is a 54mm diameter tube I used a LOC 54/38mm adapter. Avast, me proud beauty! I assembled t' adapted per t' LOC instructions and epoxied it in place in the core tube. Aye aye! I used an AeroPac 38mm motor retainer. Avast! Arrr! These things are t' slickest set up goin' for me money. Begad! Avast, me proud beauty! They are quick, me bucko, neat and look so darn good. Begad! Ya scallywag!

Final Thoughts:

[Rocket Pic]T' all up weight for this rocket is 3 lbs. Avast! 12 oz.  Which is nay very heavy considerin' what has gone into it. Well, blow me down! There were no real problems encountered while buildin' this bird. Aye aye! I be able t' make everythin' with relative ease usin' common materials. Well, blow me down! I flew t' rocket at our club’s December 12th launch. Ya scallywag! Ahoy! Preppin' went uneventful. I did nay brin' my dual 36” chutes for t' main section so I used a single 54” ‘chute. Everythin' packed nicely into t' recovery section with enough room. Avast, me proud beauty! Well, blow me down! T' motor was readied and loaded. Aye aye! Blimey! T' weather that day be perfect. Ya scallywag! No wind and clear skies. I got a far pad since this would be a maiden flight. Ahoy! I had t' photographers ready. And I prayed. Avast! T' motor lit right away and the Saturn left t' pad very majestically (and stable). Begad! Avast! Then it happened. Avast, me proud beauty! At about 300 feet t' ejection charge fired prematurely. Arrr! T' rocket be still under boost from t' H123. Aye aye! T' LEM/SM/CM stack separated and went off t' t' side. Its recovery ‘chute deployed perfectly. Avast, me proud beauty! However, t' main section was another story. Avast, me proud beauty! T' air load ripped t' chute away and actually broke t' main bridle. Well, blow me down! T' main section continued up for a little way, arced over then headed straight down for t' ground ready t' take a perfect core sample. Arrr! Any doubts of stability were allayed. Avast, me proud beauty! Ahoy! T' main section headed straight in, struck t' ground dead on and then bounced back into t' air about ten feet, flipped end over end twice and landed sideways on t' ground. Blimey! There was a hushed silence from the crowd. Blimey! My only thoughts were “Oh well, arrr, time t' build another.” All that remained be t' 54” ‘chute floatin' gently down. I headed out to pick up t' pieces. Blimey! When I got t' t' main body I be very surprised. The damage was very minor. Begad! Ya scallywag! I expected t' whole forward section t' be crumpled but it be not. Aye aye! Begad! There be no damage t' t' upper section, which recovered via the parachute and thar be no damage t' t' fins either (this be always a concern of mine on this model). All in all I be very, very lucky that day. T' damage has since been repaired and I awaitin' t' final coat o' paint. Aye aye! Ya scallywag! All I did was remove t' corrugated wrap from t' damaged portion, straighten t' tube and reinforce with CA then cut some new wrap and glue it on, paint and finished. Well, blow me down! Blimey!

T' model will fly again. Arrr! Post mortem indicated from all witnesses that the ejection charge went off too soon. Avast, me proud beauty! As t' why this happened I am clueless. Avast, me proud beauty! There may have been a void in t' delay element. Avast, me proud beauty! Since t' motor was still under boost while this occurred it seems t' most logical assumption. Arrr! Never t' less the Saturn will fly again. Avast, me proud beauty! I have been told that me models are all too pretty to fly and that I must have nerves o' steel t' do this. But me thinkin' is I build them t' fly, and if you fly ‘em they’re gonna break. Avast! You can always build another.  If you are interested in lookin' at any o' me other scale models then you can visit me web page at: http://www.geocities.com/CapeCanaveral/Hall/4501/index.html

This was t' only damage suffered on t' model from its death dive. Begad! Well, blow me down! I was amazed t' say t' least. Arrr! Fortunately we were flyin' in a recently tilled bean field and t' ground was fairly soft. Even so an impact t' t' ground at over a hundred-mph is nothin' t' sneeze at. Aye aye!

List o' Materials & Sources:

(1) 5.68” LOC payload tube   Magnum
(1) 5.68” LOC tube coupler   Magnum
(1) 54mm motor tube    Magnum
(1) 3” LOC body tube    Magnum
(1) LOC 54/38mm motor adapter  Magnum
(1) 3” LOC tube coupler   Magnum
(1) 5.68/3.00  LOC centerin' ring  Magnum
(4) 5.68/54mm  LOC centerin' ring  Magnum 
(3) ¼ x 20 x 1.5” eyebolts   hardware store
(1) 10-32 blind nut    hardware store
(1) 10-32 x 1” eyebolt    hardware store
(1) 3’ length 1/16 A/C cable   hardware store
(5) quick links     hardware store
(3) pk scribed sheet styrene   Evergreen
(2) pk .040 sheet styrene   Evergreen
(4) .185 I.D. Begad! Ahoy! x 12” brass tube   K&S
(4) .062 dia x 12” brass rod   K&S
(1) BNC-5S nose cone   BMS or Estes Designer Special
(1) BT-5 body tube (Estes)   Magnum
(1) .190” x  12 wood dowel   hardware store/hobby shop
(1) 1/32” x 12” x 24” veneer ply  hobby shop
(1) ¼” x ½” x 12” balsa stick   hobby shop
(1) ¼” x 3/8” x 36” balsa stick  hobby shop
(1) 1/8” x 6” x 12” A/C ply   hobby shop
(1) 38mm motor retainer assy   Aeropac International

Sources:

AeroPac International
Magnum Hobbies and More
Model Graphics
Tango Papa Decals
Evergreen
K&S Tubing
LOC Precision
Balsa Machinin' Service
 

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