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luke strawwalker 08-24-2011 06:29 PM

BT-80 based Saturn V/ "Saturn I-F"
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Hi all...

Well, after finishing the Dr. Zooch SLS last week, I thought I'd dust off some projects that have been partially finished. Last summer, while at the MIL's in Indiana, I turned a transition out of pink house insulation foam for a BT-80 based Saturn V. Didn't take long to figure out that a BT-80 based Saturn V, with a BT-60 based S-IVB third stage, would be perfectly "in scale" with the Dr. Zooch Saturn I/IB's I bought (but have yet to assemble.) In fact, I was playing with the idea a good while back and bought an extra pair of SLA adapter transitions, SM tubes, and CM BPC nosecones from Dr. Zooch on a big kit order. One has been sitting in the box awhile, and the other on the BT-60 S-IVB for "inspiration". So, having turned the transition and then the project 'stalling out' at the end of last summer, I decided to get back to work on it.

First off, I decided that the foam, while an excellent core for the transition, wasn't quite tight enough or really as strong as I'd like for a transition. I turned one end slightly undersize and that also complicated things, so I took a page out of the Tim Van Milligan Rocketry Workshop vids and added a tube coupler to each side (after sanding down the side that wasn't undersize so the coupler could slip over) The transition itself was made by cutting an appropriately sized "blank" from pink foam, doubled up to make the blank bigger than the diameter of the finished BT-80 transition base. A little quick work with Peter Alway's "Rockets of the World" and a calculator gave me the correct scale factor (roughly 1/152) and dimensions for the transition. Wrap a dowel in sandpaper and sand a half-round slot in each block of foam, then using epoxy or other NON-EVAPORATIVE CURING adhesive (IE NOT white glue, yellow glue, or other 'water solvent' type glues (of course they have to be FOAM SAFE AS WELL) glue the two blocks around a dowel. Once dry, cut the block down to the approximate size (octagonal) and tighten it up in the chuck of a drill (homemade lathe I built, using a $14 Harbor Freight drill for power) and turn the transitiond down to size using progressively finer grits of sandpaper.

Once the transition had the couplers glued on, I did a bit of experimenting with an online transition maker and came up with the appropriately sized transition, trimmed the pattern out of printer paper, trimmed it to final fit, and then traced it onto cardstock and cut it out. Using an old ball-point pen that no longer works and a piece of cardboard (or old mouse pad if you have a spent one) I "embossed" the corrugations in the cardstock transition by eye. Since it's on a conical part, the corrugation lines all have to 'intersect' at the center point of the transition, so this is probably better done before cutting it out, using a steel ruler through the center point as a guide for the corrugation lines as they're embossed onto the cardstock transition. Remember they have to be embossed from the INSIDE of the transition. I also added another "dividing line" halfway between the upper BT-60 end of the transition and the lower BT-80 end, using a drafting compass, to guide painting of the interstage roll pattern later on. The handy transition tool on the web also prints markings for both three and four fins if the transition is used as a tail cone, which makes it VERY easy to lay out the proper roll pattern on the transition. Simply go over the lines with a ruler and pencil to make the lines fully visible and where they intersect with the "halfway mark" you put on the transition earlier with the drafting compass establishes the roll pattern. Once the transition is marked, cut out, embossed, test fitted, and glued up, it's then ready to glue over the foam transition core. Some final trimming pretty much finished it off. I added a paper "ring" about 1/8 inch wide to the top of the BT-80 coupler tube at the transition base to make a positive step "shoulder" to keep the transition from going too far into the tube, especially under the gee forces and drag pressure of flight. I topped this thin paper ring with a decorative ribbed paper "wrap" to smooth the blend with the corrugated transition wrap above.

Next is the F-1 engine fairings. After some more calculations with the "Rockets of the World" photocopy 'worksheet', I determined that BT-55 was pretty darn close to the correct size for the fairings. Going back to the online transition tool, I printed off a "tranistion" which was basically a paper cone... the transition tool wouldn't accept "0" as a 'custom tube size' so I put "0.010 inches" as the upper tube diameter, and it worked... it printed out an cone with a TINY circle at the upper end which I then subsequently ignored in cutting out the fairing patterns. Again, since the fairings are a HALF circle, you cut the pattern in half using the "second fin line" halfway around the circumference of the cone. Next, emboss the pattern similarly to how was done with the upper stage tranistion, but this is a bit more difficult since ALL the corrugations would converge at the point. It's best to end every other one about 3/8 inch or so from the fairing "tip", or even every 2 for each 1 that goes all the way to the tip. This makes a neater looking fairing. Next, the four transitions are glued to the outside of a BT-55 tube, using white glue and set aside to dry...

Here's the completed transition, on top of the S-II stage tube

More later! OL JR

luke strawwalker 08-24-2011 06:30 PM

5 Attachment(s)
These fairings are using the same method Dr. Zooch uses in his kits for external half-round fairings-- gluing "skins" onto an appropriately sized tube, and then cutting them out of the tube wall. Once dry, carefully cut around the skins and liberate the fairings from the parent BT-55 tube. The curvature of the tube has to be "corrected", as if you put the fairing on a flat surface, you'll quickly see that it touches at three points-- the two rear ones and the very front tip, with the sides off the surface. Using an old ballpoint pen inside the fairing for support, gently "recurve" the fairing to a tighter diameter, getting tighter and tighter as you move toward the tip. The tip should basically roll right around the point of the pen. Work slowly to avoid creases. Next, measuring up from the base of the fairing the appropriate amount (since the fairings extend past the back end of the tube a certain amount, and are NOT flush with it) mark the fairings at the appropriate place and measure the width there. This will be the "outside diameter" of the "half-moons" that will go inside the fairings to shore them up and give a place to mount the F-1 engines later on. Using a drafting compass, lay these out, cut them out, and test fit for correctness. I traced around a BT-80 to get the "inner diameter" of the half-moons, and then traces the test fit patterns (which looked like a "D" at that point) onto cardstock and cut the "half moons" out of the cardstock and glued them onto a sheet of 1/8 balsa. These are then cut out when the glue is dry, and sanded to shape, and then glued inside the fairings at the proper place (recessed from the end of the fairing so they're flush with the end of the BT-80 when the fairing is glued on the rocket body-- measure up the inside of the fairing and put a line there to guide the glue-up). Once dry, the fairings are then custom fitted to the tube before being glued in place.

The fairings are custom fitted to the tube by installing a coupler or two inside a spare piece of tubing to shore it up, and then wrapping the tube with sandpaper, and holding the fairing at the proper angle, it's sanded up and down the length of the tube until it conforms snugly to the tube. This will sand the outer edges and the "half moons" at the same time (I did SOME pre-fit sanding to the half moons after cutting them out to get them to conform fairly closely to both the fairing and the tubing to minimize the final custom fit sanding).

I decided after getting the fairings done for the Saturn V, to go ahead and do a second project at the same time that I had in mind a couple years ago when I bought the parts for the nosecones of these rockets-- the "Saturn I-F" that was proposed to replace the "Cluster's Last Stand" amalgamation of Jupiter and Redstone missile-derived fuel/oxidizer tanks used to build the Saturn I/IB first stage. These made the development of the Saturn I first stage easier (and cheaper) but it also meant that the stage weighed a LOT more than necessary structurally (which of course hurts payload-- it's not QUITE as critical on a first stage, which has to save around 10-11 pounds to add a single pound to ultimate orbital payload, but still, the added weight and complexity also increased the cost of materials and manufacturing of the stages, which drove up operational costs for Saturn I/IB and ultimately helped, with other factors, to doom the program). The proposed solution was to create a new first stage, similar to the S-IC first stage of Saturn V, using a single LOX tank above a single kerosene tank separated by an intertank ring. This proposed stage would dispense with the 8 engine cluster of H-1's, and replace them with a pair of F-1 engines like Saturn V, and incorporating the F-1A improvements when they came online. This new stage could also be strapped onto the sides of a Saturn V (using two or four) as Liquid Rocket Boosters, or LRB's (though the term hadn't been coined when it was proposed-- they were called "pods" back then!) Such "dual use" would have really helped the Saturn program and would have most likely been incorporated had the shuttle not happened and the Saturn program kept going (in some form) and was "evolved" over time. This proposal is also quite close to the "Saturn C-3" proposal from the early days of the Saturn program. To replace the Saturn IB, this twin F-1 powered first stage would have been topped with a regular Saturn IB S-IVB stage, IU, SLA panels, CSM, and LAS tower. (See the Saturn Studies Summaries in the scale area for more information on all this).

SO, after re-reading the relevant studies and diagrams, doing a little "comparative anatomy" on the "booster pod" diagram, Saturn IB diagram in "Rockets of the World", and doing some careful measurement and calculation, I came up with the necessary figures to construct the 260 inch Saturn I-F first stage, and mate it to the 260 inch S-IVB second stage of a standard Saturn I-B. Next, the BT-60 is laid out with a reference line and the appropriate measurements to delineate the various tanks, intertanks, forward and aft skirts, and interstages needed. Then the fairings are glued on at the appropriate points. The "half moons" are lined up with the aft ends of the main body tube (BT-80 for the Saturn V, BT-60 for the Saturn I-F)
Once glued on and lightly filleted to ensure no gaps in the bond, the fairings are trimmed and lightly sanded until they're parallel with the aft end of the main rocket body tube. (the difference in curvature means they'll be slightly "out of plane" with the rear of the tube-- this effect is most pronounced on the smaller diameter Saturn I-F, but noticeable on the Saturn V as well). A slight trim with the hobby knife followed by a good sanding with 220 grit really gets everything trued up...

Next everything's test fitted... The Saturn V will have a tube coupler at the S-IC/S-II cylindrical interstage (might make it a baffle-- haven't decided yet, nor on what I'll use to power this (single D/E with outboards for a five cluster most likely) or the Saturn I-F (pair of 18mm's or 13mm's perhaps). Here's the final layup of the fairings on the S-IC on the Saturn V.

And here's the Saturn V S-II stage, conical transition interstage, S-IVB, SLA balsa transition, and CSM cones.

More later! OL JR

luke strawwalker 08-24-2011 06:32 PM

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Here's what I've done so far... the Saturn V all mated up and layed out. Still have to do the corrugated wraps at the appropriate locations for the interstages, intertanks, and fwd/aft stage skirts, thrust structures, etc. plus all the external details and such. I have SOME ribbed cardstock, but I think the ribs are too big for much above the first stage.

Here also is the Saturn I-F... Since this rocket is 260 inches (BT-60) on both stages (like Saturn I-B) it's made from a single length of BT-60 tubing, which has been marked at the appropriate locations for the corrugated wraps of cardstock for the interstages, intertank (on the first stage which would have been constructed like a "mini S-IC", even using the same Saturn V F-1 engine fairings!) and fwd/aft stage skirts and such.

Now I've got to hunt down some finer ribbed cardstock paper...

Later! OL JR

Bill 08-25-2011 11:31 AM

Originally Posted by luke strawwalker
Now I've got to hunt down some finer ribbed cardstock paper...

If you are unable to find some, here is a technique which may give you the result you want, with some practice:


MarkB. 08-25-2011 01:34 PM


I was the original benefactor of Bill's technique, and I gotta tell you it does take some practice. I got my cutter at Michael's, the Martha Stewart version, on sale. And it does work . . . .

I'm no where near ready to try a tapered section, but be aware that I struggle in all things paper and some (or all) of you may pick it up faster than I. After a month or two of practice, I'm now ready to do the relatively simple corregations on my Shenzhou. I have used the 110 pound paper and it works fine.

luke strawwalker 08-26-2011 01:36 PM

5 Attachment(s)
Originally Posted by Bill
If you are unable to find some, here is a technique which may give you the result you want, with some practice:


Thanks for the tip, Bill! Got any pics to go with it?? (pic's worth a thousand words... LOL:))

I found some ribbed paper, but it was an interesting story how it came about...

Interesting how things work sometimes. I emailed Wes at Dr. Zooch and inquired about the corrugated paper he uses on kits like the SLS I just finished, that has a ribbed "intertank" area. In "the old days" kits like the shuttle and Atlas had ribbed mylar "party streamer" material for the intertanks and thrust structures. It worked pretty well actually, despite being a bit difficult to cut unless you had a VERY sharp hobby knife blade! He replied that he gets it at the chain store "Michaels". Ok... I've gotten some there before (see pics below) but they never had a whole lot-- maybe their Michaels stores in Maryland are far better supplied than ours are. Or, maybe I haven't actually been in Michaels in awhile and what was rare as hen's teeth last time I was in there is now commonplace. Since we don't have a Michael's very close by, that's certainly possible...

As it turns out, yesterday while I was doing laundry and enjoying our first inch of rain in about the last 90 days, the wife calls and announces she's broken down between her school she teaches at and our six year old daughter's school 10 miles away-- so she needs a rescue. The nephew and I jumped in the truck, grabbed a gas can (was pretty sure from her description that she'd run the car out of gas-- AGAIN... she does this almost yearly-- what do women have against keeping a FULL TANK OF GAS!?? ) So, we drive the 30 miles to Keira's school, pick her up from after-care, and go find mommy and put a five gallon jerry can of gas in her car-- presto it's fixed. After an early supper, we head for Michael's (since I'm in suburban Houston now anyway and it's not far off the beaten path from there) and I start searching high and low for ribbed cardstock. They had a display of textured cardstock just inside the door, but the only thing they have 'ribbed' is some "corrugated" two-ply cardstock that looks basically like fine cardboard without the top outer flat layer-- it's a corrugated sheet glued to a flat backer sheet. Everything else is foo-foo girly stuff of no use to anybody... So I make my way over to the cardstock aisle. In pidgeonholes (pidgeontrays is probably more accurate) from floor to ceiling practically, the whole length of the aisle, is the cardstocks, in every imaginable color and various textures-- EXCEPT RIBBED! They have "woodgrain" pattern, which is similar to ribbed except the "grain" is neither evenly spaced or parallel to each other-- useless. They have "crosshatched" similar to "hand-made" or 'linen' paper... and they have them in 395 different colors... but NO RIBBED. After 20 minutes of searching every tray, no joy. Finally in desperation I start searching the "paper collections" across the aisle.

SUCCESS! I FINALLY find a pack of "foil covered" cardstock that is ribbed. It comes in a 30 sheet pack with "cross-hatched" and in various gaudy metallic colors (actually kinda cool in a way, but hardly necessary for my use) and the cross-hatched is worthless to me, but hey, Keira can use it for crafts... but the pack is $20. As I'm looking through every other pack on the aisle hoping to stumble across something cheaper that's ALL ribbed cardstock and not foil covered, an Asian lady comes down the aisle and thrusts a 40% off coupon in my hand-- "Here-- I have an extra!" she says as she briskly keeps moving... "THANKS!" I call after her... now the $20 pack of paper doesn't seem SO much like highway robbery... After finishing my search of the packs, no such luck-- it's the $20 foil covered ribbed paper or NOTHING. So I get it. Wandered back over to the front display and check again, in case I missed something... Pulled out a sheet of the "corrugated" stuff and looked at it, flipped it over, and noticed "The Paper Company" sticker on the back, which I've seen on the back of some of the paper wraps in Dr. Zooch kits. So I figured "what the heck" and bought the sheet, though it's probably too coarse a corrugation for anything I'm likely to build in the next year or two, but I'd rather have it in storage than not have it and need it!

SO, here's the foil-coated ribbed cardstock-- by AC Specialty Paper, (30) 12x12 inch sheets, half are ribbed, the other half cross-hatched. On the back it says

Here's the "corrugated" sheet I bought, and a pic of the label on back that matches the partial labels I've seen on the back of Dr. Zooch ribbed paper wraps...

Here's what I got at some craft store or other along the line (maybe Michaels, maybe somewhere else in Indiana)... had it in storage and used some of it. I also had some black ribbed cardstock I picked up at Michaels I think, but I can't seem to find it now... it's probably in storage around here somewhere...

Anyway, that's the cardstock oddyssey... LOL Might have better luck finding this stuff from some scrapbooking supply house online...

Later! OL JR

luke strawwalker 08-27-2011 02:40 PM

5 Attachment(s)
Ok, finally got some more work done on the Saturn V/Saturn I-F. Got to checking in the ROTW and found that the Saturn V had 108 corrugations on the S-IC intertank, and 216 on the S-IC forward skirt. IOW, the corrugations should be about half the size on the fwd skirt as on the intertank. Peter Alway lists the S-IC thrust structure as having the corrugated stringers 2 degrees 48 minutes apart . Figuring that a circle is 360 degrees and every degree should be 60 seconds of arc, that's 21,600 minutes of arc in a full circle, divided by 2 degrees 48 seconds per stringer (168 seconds of arc) gives 128 stringers (rounded off-- close enough for gov't work). Close enough to the 108 on the intertank to use the same corrugation pattern. SO, I used the "wide corrugation" paper I've had for awhile and custom fitted the panels between the engine fairings on the base of the S-IC and then cut the intertank band that links the top of the kerosene tank and the bottom of the LOX tank. For the forward skirt at the front of the stage, I switched to the foil-coated paper I bought a couple days ago. Carefully marked and cut out with a hobby knife, back coated with white glue, and rolled onto the tank. Here's the results.

Next I switched to the Saturn I-F. Since the first stage/booster pod is built almost identically to the Saturn V S-IC first stage, only smaller, I used the same corrugated white paper for the thrust structure and intertank, and switched to the finer corrugated foil paper for the first stage forward skirt, interstage, and S-IVB upper stage aft skirt, and the S-IVB fwd skirt. SO all the wraps are done on the Saturn I-F.

Next I have to continue debating what to do about fins on the Saturn I-F.... The "booster pod" would have been the basis for the first stage on the Saturn I-F, and that booster pod is not shown with fins. The booster pod is very similar to the Saturn C-3 proposal from 1961, which was never built, and it was never shown with fins (of course the early Saturn I's had no fins either.) SO, considering this is supposed to be an 'evolved' Saturn IB, it's likely that the fins would have been dropped. If we presume they were, then I'll need some kind of add-on fins for flight (and I already have a design in mind for removable clear flight fins). The other alternative is that they'd have grafted on some Saturn I or IB fins or Saturn V fins-- though the fact it only has two engine fairings complicates that issue somewhat. Guess I'll play with it in Rocksim and see what I can come up with. Given the fact that some work had been done to get rid of the fins on Saturn V, which wasn't implemented due to it's low production (but would likely have been implemented had Saturn V production resumed with a second run-- there were literally THOUSANDS of weight and labor saving changes ready to be applied to a second run of Saturn boosters had production ever resumed!) So, that being the case, it might be simplest to go with clear fins and call it good...

More work to do! Later! OL JR

luke strawwalker 08-27-2011 03:24 PM

5 Attachment(s)
Here's some research that I've come up with on the "Saturn I-F" or "Saturn II" as it's called in one graphic. In fact that graphic shows the thing having Saturn V fins, but it's notional, not anything "official" from NASA studies or anything, but it does look pretty good!

Here's the original graphic I was working from from the Improved Saturn Studies from 1966...

And here's the results of some heavy measuring and number crunching using figures listed in the graphic above, integrated with measurements from the graphic itself and relevant data pertaining to the Saturn IB and Saturn V...

Here's a picture of a model of the finished product (display model, by Mike Robel from

Of course if it used Saturn V fins, these would be the measurements (but they'd probably have to be oversize, as is typical for Saturn V models).

More later! OL JR

luke strawwalker 08-27-2011 03:31 PM

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Of course the other alternatives if using fins would be to use fins off of Saturn I or Saturn IB. The problem with that is the fact that the Saturn I-F uses only two engine fairings, but then again, maybe a combination of fins would have been used-- say 2 Saturn I Block II fins in between the fairings, and Saturn V fins on the fairings themselves... That would work. Saturn IB fins would be more difficult to integrate, being swept, and less effective due to their smaller size. Putting a pair of them between each fairing also would create some weird aero-effects as the air being diverted by the fairing would impinge on the fin and be "trapped" between the fin and fairing, so I don't think that would work at all...

Here's another view of the Saturn V fins with dimensions...

And some more information on the Saturn I Block II fins which would work well centered between the fairings with Saturn V fins ON the fairings...

And this graphic has the relevant measurements for Saturn IB, including the fin dimensions at the bottom...

Later! OL JR

luke strawwalker 08-27-2011 05:32 PM

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Finally finished with the corrugated wraps. Now she's starting to look like a Saturn V!

First a little pic of a proposed alternative vehicle to Saturn V-- the INT-20. This would have mated a Saturn V S-IC first stage with either 3 or 4 F-1 engines (three inline like Atlas, or four with the center engine missing and it's plumbing capped off-- most versions showed four) topped by an S-IVB Saturn V third stage. This vehicle would have been capable of lifting 78,000 pounds to orbit with three F-1 engines or 132,000 pounds to orbit with four F-1 engines. It's a neat prototype in its own right, as it too was proposed for a replacement for Saturn IB, since Saturn IB had VERY LITTLE payload capability with a CSM on top and couldn't even lift a lunar capable CSM (to the cut the weight, only half the Service Module's regular SPS fuel load was carried when the Apollo CSM was flown on Saturn IB). This vehicle would have used the same stages and assembly lines as Saturn V (in fact the INT-20 S-IC stage was completely interchangeable between the Saturn V configuration and the INT-20 configuration-- there was basically a modification "kit" to make it an INT-20 first stage from the basic Saturn V configuration) and therefore would have been very economical, because unlike the Saturn 1-F or Saturn II, it would not have required a new stage assembly line and tooling (The 1-F would have been good to have if uprated Saturn V's were used, as the first stage of the 1-F doubles as an LRB for the Saturn V itself, and is manufactured almost identically to the S-IC, just smaller, simplifying things and reducing costs (theoretically). Here's the pics of the Saturn in INT-20 mode...

And finally, the 'all up' Saturn V with the S-II stage included, supported by the S-IC and topped by the S-IVB and Apollo stack.

Later! OL JR

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