BT-80 based Saturn V/ "Saturn I-F"

[luke strawwalker]

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]

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]

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

[Pem Tech]

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

Later! OL JR

Hey, let us know where you find ribber cardstock, so far I have been unable to find it anywhere.

[luke strawwalker]

Hey, let us know where you find ribber cardstock, so far I have been unable to find it anywhere.

I've got SOME that I got from Michael's... it's a rather "coarse" ribbing though, maybe 1/16 to 3/32 wide ribs with a shallow 'trench' between them. I think it'll look about right for the S-IC thrust structure and Intertank, but above that, I REALLY think I need a finer "corrugation".

If anybody has any suggestions I'd LOVE to hear them!

Later! OL JR

[FastCargo]

Luke,

I really like this project...Saturn Vs that are a bit bigger than the Dr. Zooch designs but not so huge as the Estes ones or bigger. Plus being able to use more common tube sizes is a plus! If I may ask, what BT are you using for the SM?

I kind of did the same thing in reverse, using a BT-50 as the base for a 13mm Saturn V. I figured once I laid out the basic design, I could build the proposed derviatives simply and cheaply (SRBs, Skylab, etc..).

FC

[luke strawwalker]

Hey, let us know where you find ribber cardstock, so far I have been unable to find it anywhere.

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 www.americancrafts.com


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

[hcmbanjo]

Thanks Luke!
I've been looking for the same type of ribbed paper in every scrapbook aisle in town without luck. I knew it was out there somewhere.
I'll stop by Michael's next week.

[modeltrains]

but I'd rather have it in storage than not have it and need it!

Understand the concept

Neat project ya got goin here.

[luke strawwalker]

Well, been doing some research on the Saturn V... Want to detail the thing pretty well and want to do it accurately. Got some FANTASTIC infographics available over at http://www.apollomaniacs.com/apollo/...aft_menu_e.htm

Everything from the CM, SM, LES tower, SLA panels, and all three stages of the Saturn V, plus the first stage of the Saturn IB. TONS of terrific information.

Been trying to digest it all and integrate it with the stuff in "Rockets of the World" as well as a couple other Saturn V sources I have around the place, as well as information from John Pursley's website http://www.accur8.com/ as there's lots of good info on there as well.

Later! OL JR

[NJRick]

Luke,
I am brand new to the Forum... you are doing an awesome job on your Saturn V....I hate to ask a dumb question, but how tall is your Saturn? it looks fantastic so far!

Rick

[luke strawwalker]

Thanks Rick... nice to have you aboard!

Right now, standing on it's F-1 engine fairings to the top of the Apollo Capsule (no tower yet) it's about 25.5 inches tall.

Still a lot of work to do yet... probably start laying out the detail locations on the vehicle and adding them one by one. All the cable tunnels, propellant line fairings, umbilicals, vents, etc...

Thanks for the compliment! Hope you enjoy TRF.

Later! OL JR

PS. You might want to check out the Dr. Zooch SLS beta build I just finished last week... I'm particularly proud of that one! TONS of pics and build hints as well!

[caveduck]

Wow this is pretty cool stuff!! Love to see folks taking on the more significant projects.

I thought I'd mention a method for making corrugated wraps that some famous scale modeler (John Langford? John Pursley? pretty sure it was one of those two) showed me a long time ago. The idea is to mold them in graphite epoxy in a jeweler's wax mold. You pour a flat slab of wax big enough for the wrap and then use various scribing tools (custom made if need be) to create the rib pattern. Then you cast the wraps by mixing some powdered graphite with 30 minute epoxy (it needs to be a fairly flexible kind), slathering it into the mold and pressing a sheet of model airplane tissue into the back of it to help it hold together. I saw some parts made with the technique and they were pretty darn awesome. I also think Pursley used the same method to make the detailed caps for his shuttle SRBs.

[NJRick]

Luke,
I actually read your Beta build last week...(I eat lunch at my desk here in the office) I went home and marked it as favorite on my home computer for future reference..... That kit turned out fantastic!
This site is so great for builders like myself, who are returning to the hobby (these are my first builds in 30 years), to learn from. You have been very helpful to a newbie! I am eyeing that kit and the Doctor's Shuttle...not sure I am there yet to take on the Shuttle...but man does that thing look sweet. (OK..I am eyeing his Mercury Atlas, Saturn V, Vostock.....I had forgotten how much fun it is to build and fly)

Rick

[luke strawwalker]

Just so nobody thinks I'm slacking off...


Taken from the apollo maniacs site, checked against some other sites including John Pursley's accur8.com, NARTS Saturn V blueprints, http://www.apollosaturn.com/
http://spacemodels.dk/saturnv.htm
http://www.saturnvmodel.info/
http://www.apolloarchive.com/ http://ricksternbach.com/SatV/Saturn_V_Clinic.html

Here's some pretty straight up graphics...





I'm going to "clock" all the details to their proper positions on the rocket stack, including the CSM and BPC. I've done some sketchwork of the complete stack in each of the four positions (I, II, III, and IIII, with their CSM/SLA equivalents according to the apollomaniacs stuff (-Z Pos I, -Y Pos II, +Z Pos III, +Y Pos IIII) Once I "map" all the details, I can then transfer them to a "wrap" evenly divided into four quadrants (first scan above) with all the detail locations located on it, which can then be wrapped around the tube and the ends taped together, aligned with the reference line on the body tube, and then correctly radially locate all the details onto the body tubes and forward and aft skirts, etc. Now I have to do one for the S-IVB (it's pretty complicated as well, despite not having as many propellant line fairings as the S-II, there's a lot more details like retrorockets, auxiliary power units, LH2 fill/drain fairings, cable runs, etc... The S-IC should be the simplest of the lot, and I'll save it for last.

More later! OL JR

[bradycros]

I like all the details your giving, good work!

[luke strawwalker]

Thanks! I appreciate it!

Glad to do it... Lord knows I've learned enough from other folks-- I like to help out if I can...

Need to get back to work on it... this stuff of taking care of the house, the cows, and the parent's water well keeps getting in the way...

Later! OL JR

[luke strawwalker]

Got a little more work done today before I had to go fix the old man's water well... and haul a TV to recycling center for my brother, and get parts for the well at Lowe's...

SO, here's the S-IVB wrap with all the details laid out by position number (I,II, III, IIII) Everything above the S-IVB switches to coordinate locations by axes-- (-Z, -Y, +Z, +Y, with the central vertical "roll" axis being +X forward and -X rearward). But that's another story...
Here's the wrap...

And here's a good source for details, along with photos I have of the JSC Saturn V, and ROTW, and John Pursley's accur8.com site, and a few others... including the NARTS Saturn V blueprints I bought years ago (despite them being muched on in storage by silverfish).




Later! OL JR

[Fred22]

Im a bit of a Saturn V nut so I will have to follow this. Good looking build
Cheers
fred

[NJRick]

Luke....this rocket is going to look sweet!

[luke strawwalker]

Luke....this rocket is going to look sweet!

Thanks... I hope so, if I can ever get any work done on it!!!

RL keeps intervening!!!

later! OL JR

[luke strawwalker]

Ok... back to the drawing board...

Interesting topic of conversation over on the nasaspaceflight.com/forums came up about "what if Apollo had continued..." In part of the discussion, it came to replacing Saturn IB's "cluster's last stand" first stage powered by eight H-1 engines with "something else".

At one point the 260 inch monolithic SRM being developed and tested by Aerojet was proposed, but the thing was SO massively heavy it was going to require an ENTIRELY new integration and stacking design at KSC to make it work, and that wasn't in the cards. As it was, only the half-length motor was ever built and test fired before the project was canceled.

The subject came up about LIQUID replacements for the S-IB stage... interestingly enough they'd been proposed but of course never developed, due to the fact that, being a first stage, weight and ISP inefficiencies don't hurt performance anywhere NEAR as much as they do on upper stages, where weight and ISP is critical to performance. S-IB was actually somewhat of a weight savings over the earlier Saturn I first stage it replaced, though of course the basics of the design in using multiple tanks clustered together could NEVER be as efficient as a monolithic fuel tank and monolithic oxidizer tank, even separate bulkhead tanks like the Saturn V S-IC stage used. But, you have to save about 11 pounds of weight on the first stage to increase payload by 1 pound, unlike on upper stages where it's much closer to 1 pound weight saved equals 1 pound of extra payload (this is especially true of escape stages leaving earth for the moon or elsewhere). SO it was judged not worth the expense to develop a replacement.

Now, in an alternate universe, which the thread presupposed, where shuttle was deemed 'a bridge too far' and was rejected in 1972 instead of being approved and all Saturn hardware and capabilities ultimately scrapped, the opposite decision is taken to "build upon what we have" (much like the Russians did incidentally) and so a program was initiated to evolve Saturn into something more affordable and sustainable-- cheaper to build, cheaper to integrate, and cheaper to fly. Obviously in this paradigm, you have to streamline production and reduce programs where possible-- engine programs, stage programs, etc all soak up funds and make the overall program more expensive, so being able to eliminate the H-1 engine, and the S-IB first stage would have been highly desirable. Replicating it's performance and capabilities (and actually improving upon them) would have been nice side-benefits, especially if it could be done with the existing F-1/F-1A engines and structures similar to that in use on the S-IC Saturn V first stage, and using the existing S-IVB stage, which would surely have switched to the J-2S engine at that time.

Now, Improvements to Saturn V had been proposed including using up to FOUR strap-on liquid rocket booster pods (LRB's) to supplement the Saturn V first stage thrust. There were similar proposals using SRB's of various type and designs (from 120 inch SRB's from Titan III, to 156 inch "notional" SRM's (which eventually became the SRB's I suppose) to even mammoth 260 inch monolithic SRM's by Aerojet). Basically ALL the proposals for Saturn V boosters ignored or glossed over various important constraints on the KSC infrastructure, such as the fact that the acoustics (noise) from the ignition and liftoff of THIRTEEN F-1 engines AT ONCE from a Saturn V (5 F-1's) with FOUR LRB's (2 F-1's EACH) would have broken every window in the eastern half of the state of Florida...

Now, there were proposals to use this dual F-1 booster as a first stage replacement. Someone pointed out on the NSF thread that this wasn't particularly feasible-- the thrust from TWO F-1's was ENTIRELY too much for a Saturn IB type vehicle (unless it was ONLY launching massive payloads instead of crews, which would have required a BIG redesign of the S-IVB most likely). The EIGHT H-1 engines of the S-IB first stage produced 205,000 lbs thrust each (in their last upgrade) for a total of 1,640,000 lbs, a little more than the 1.5 million pound thrust of the stock F-1. Two F-1's on the first stage of a Saturn IB type vehicle would produce around 3 million pounds of thrust, about DOUBLE the Saturn IB first stage! Talk about "blink and you miss it!" The gee loads on a crew would have been unedurable! A single F-1A would have produced 1.7 million pounds thrust at liftoff and would have been a suitable replacement for the cluster of H-1's. Assuming you desired to keep the initial liftoff thrust/weight about the same, and simplified the control of the vehicle at the same time, using a standard F-1 on the first stage augmented by a PAIR of H-1's mounted on either side in the outboard positions (to provide roll control and augment thrust) would have increased the liftoff thrust substantially (to nearly 2 million pounds) allowing for heavier payloads without overaccelerating the stack (would probably have required shutdown of the outer 2 H-1's before burnout, just as the inner four H-1's shut down early on S-IB and the central F-1 shut down early on S-IC.) Weight savings by switching to monolithic tanks on the stage similar to S-IC and powering the stack by a single F-1/F-1A and implementing a pair of roll-control verniers or other methods would have probably been preferable, ESPECIALLY for a crew launch vehicle! In addition, this S-IB stage replacement could have produced a SINGLE F-1/F-1A booster for use with Saturn V-- a pair of which would have provided SEVEN F-1's thrusting at liftoff-- surely all the "boost" a Saturn V would ever have needed!

SO-- the "Saturn I-F", which I've faithfully copied from the EXISTING NASA STUDIES OF THE TIME, is basically over-powered and unrealistic. A SINGLE F-1 booster is MUCH more likely, ESPECIALLY if using the substantially higher-thrust F-1A engine! Such a booster would have had a realistic (if perhaps unaffordable or unnecessary, if no large payloads needing it were funded) performance for a booster for Saturn V, if needed, and would have had double duty as a crew launch vehicle first stage.

Such a single F-1/A first stage/S-IVB second stage crew launcher would basically have given NASA the safety benefits touted for the Ares I "Stick" crew launcher (two stage launcher, single engine on each stage) without the problematic issues such as motor buzz and the impossibility of shutting down an errant SRM first stage, and trying to do an abort off an exploding SRB "unzipped" by range safety in the event of an abort, which would have filled the sky with burning chunks of APCP. A single F-1/A booster would have had the same benefits of a single engine on the first stage, coupled with a single engine on the second stage, with one staging event, and the added benefit of being able to simply turn off the F-1 in the event of an abort.


SO, back to the drawing board... I'll have to replace the twin F-1 first stage on the "1-F" with a single F-1 version... no problem as I can build a twin of it for a pair of LRB's for the BT-80 Saturn V (which would have had NINE F-1's thrusting at liftoff, STILL too much IMHO, but if you deleted the center engine on the S-IC itself and capped it off, you'd have had a more manageable EIGHT F-1's with the twin-F-1 boosters on either side... (which would likely be more efficient anyway as it would allow the S-IC to burn longer with the same fuel load, with only 4 F-1's guzzling the fuel instead of 5...)

Later! OL JR

[NJRick]

Luke,
what a fascinating post....quick question for you....one of the limitations with the Saturn 1b (my all time fav rocket...) was its inability to lift a fully fueled CSM . I believe the only payload that an Apollo equipped 1b ever carried was the docking adaptor on ASTP. with those limitations, do you think that a single F-1a would have still been the option NASA would have chosen? Seems like could have had the same payload limitations as the 1b?

Rick

[luke strawwalker]

Luke,
what a fascinating post....quick question for you....one of the limitations with the Saturn 1b (my all time fav rocket...) was its inability to lift a fully fueled CSM . I believe the only payload that an Apollo equipped 1b ever carried was the docking adaptor on ASTP. with those limitations, do you think that a single F-1a would have still been the option NASA would have chosen? Seems like could have had the same payload limitations as the 1b?

Rick

Hey Rick...

Actually Mike Robel (who's done some REALLY cool alternative Saturn models (static) and I were discussing just this issue over on YORF. He pointed out much the same thing you just did-- that while the 3 million pound thrust of a pair of F-1's APPEARS at first blush to be "too much" for a Saturn IB replacement vehicle, in actuality it is not, and for the very reasons you pointed out. The Saturn IB's payload limitations basically doomed it. For any type of mission with the Apollo CSM beyond LEO but still in Earth's vacinity (say to geosynchronous Earth orbit or the Lagrange points closer to the moon such as L1 or L2, a fully-fueled capability on the CSM was absolutely required. Being able to launch a substantial payload with the Saturn IB replacement would also have been highly valuable, especially if you decided to do an Earth-orbiting space station project and resupplying that station periodically, unlike Skylab which basically launched "fully stocked" and used the LOX tank of the converted S-IVB stage "workshop" for a "septic tank". A continuously manned, periodically resupplied space station in LEO by the US would have required some sort of resupply/disposal capability, just as the Soviets learned with their Salyut stations when they developed the robotic Progress freighters for exactly that function. If you developed something akin to say the ATV/HTV, or even a much simpler and cheaper "MPLM" type "pressurized tuna can" that could be loaded with supplies, water, boost propellant, etc. that was carried up under the SLA panels on the top of the Saturn IB replacement's S-IVB stage to orbit, and then have it extracted by a transposition and docking manuever identically to how the CSM docked and extracted the LM from the spent stage, and then transported that module to the space station and docked it to the station, or even simply delivered it into station keeping with a space station where it could be grappled by a robot arm and berthed to the station, leaving the capsule free to dock with the station independently of the resupply module, that module could then be unloaded at will and filled with refuse from the station, and jettisoned for reentry, either from it's own thruster system like Progress, or docked to by the CSM and then dropped back into the atmosphere by a partial de-orbit burn by the CSM followed by undocking and then a prograde burn so the Apollo could reenter later, well away from the disposed of resupply module.

In addition, there were plans for small "conical shaped" space stations that would basically fit in the location of the SLA adapter panels of the Saturn IB. Such a design would be an excellent starting point for space station modules which could have been delivered by a Saturn IB to orbit and brought to the space station for assembly by the CSM, then released and grappled by a robot arm which would permanently dock it to the station at a node connector, much as was done with shuttle and ISS. This is most likely how any successor stations will be constructed in the future now that shuttle is retired (or free-flying modules with propulsion systems sufficient to rendezvous and dock with the other modules forming the station, done either by remote control or autonomously as the Mir modules and Progress freighters did/do... this allows for larger modules to be launched unmanned, and this paradigm certainly would have worked for a Saturn IB successor just as well as it would for Proton and the modern EELV's and/or Ariane V, but OTOH it's AWFULLY convenient to launch a manned spacecraft with the module, like shuttle did carrying most of the ISS modules to orbit.

To be able to do it though, you need a "high thrust" first stage capable of getting that much weight off the ground and up and moving. With a fully fueled CSM and a substantial payload module under the SLA panels, the twin F-1 vehicle would have been ideal. Now, as the fuel is expended and the stage nears fuel depletion and burnout, the 2 million pound + thrust is going to be too much, and start building gees quickly. It would be necessary to shut down one of the F-1's early, since the F-1 couldn't be deeply throttled, and that would complicate things a bit. The off-center thrust shouldn't be too much of an issue... after all shuttles flew for 30 years with EXTREMELY off center thrust from the SSME's on the orbiter with the heavy nearly-half-full ET hanging off the side of the orbiter. This might have been a bit "radical" at the time though... roll control might be something of an issue with one F-1 shut down, but owing to the off-center thrust I think it would still be controllable. The remaining F-1 would have had to 'slew' somewhat to thrust through the center of gravity once the other F-1 was shut down, so the vehicle would be flying "slightly sideways" (much as shuttle did) until the first stage burned out.

In thinking about it, the single F-1 teamed up with a pair of H-1's presents some interesting possibilities. I wish I had access to the tools and knowledge to be able to analyze the possibilities properly, but a thought exercise is still possible. Obviously the addition of another 400,000 lbs thrust in addition to the 1.5 million pounds thrust of the standard F-1 would give you just under 2 million pounds thrust, a pretty decent 'bump up' from the standard Saturn IB. Now as the stage gets lighter from propellant burning, acceleration increases (gees) and at some point you're going to have to either deeply throttle or shut something down to reduce thrust. Saturn IB did this by shutting off the center four engines and running on the outer four for 20-30 seconds or so (IIRC, but not exactly) before stage burnout. You have two choices on this particular stage-- shut down the twin H-1's, or shut down the F-1. Shutting down the twin H-1's leaves you without roll control, but this might not be critical. But it also wouldn't drop but about 400,000 pounds of thrust or so-- the F-1 would still be churning out 1.5 million pounds thrust, which is about what the Saturn IB started off with. This would probably throw too many gees on the payload/structures. The other possibility, shutting down the F-1, means you can now burn your twin H-1's quite a bit longer, since they burn propellant FAR slower than the hungry F-1 does. It drops your thrust to about 400,000 pounds, or roughly the equivalent of a PAIR of J-2S's. This makes for some interesting performance. You're still carrying the weight of the probably 80% empty first stage propellant tanks, and you're dragging along tons of dead weight of the F-1, but you're going to burn the first stage quite a while longer on just the pair of H-1's than you would otherwise. The thrust is somewhat low, but it shouldn't be underthrusted to the point gravity losses become objectionable. Essentially the first stage would then be acting somewhat like a twin-J-2S "second stage", only powered by kerosene burning H-1's and using the first stage tankage, and dragging along the dead F-1 (I don't think for a moment it'd be worth it to design a separation system into the stage to drop the F-1 after shutdown). Once the twin H-1's have burned to propellant depletion, the first stage is jettisoned and the single J-2S upper stage takes over to deliver the CSM/cargo to orbit.

Later! OL JR

[luke strawwalker]

Got some more work done on the Saturn V... the S-IVB is now completely detailed. All scale details incorporated in the proper locations...

Here's the overall side view including the SLA balsa transition and BT-50 service module, along with the balsa Command Module nosecone. You can see the main systems tunnel, auxiliary systems tunnel, forward umbilical connect and a flat telemetry antenna...

Here's the other side, showing the APS, LH2 feedline fairing, LH2 chilldown pump fairing, and ullage rocket...

The main and auxiliary systems tunnels, the telemetry antenna in the middle, and the forward umbilical at the very top edge.

The APS, chilldown pump fairing (made from a sanded down to scale toothpick), LH2 fill line fairing (half of a sanded down bamboo skewer), aft umbilical connect plate (cardstock), main systems tunnel, ullage rocket, and LH2 chilldown return line fairing (sanded down toothpick)...

Ullage rocket, LH2 chilldown return line fairing, LH2 fuel line fairing (sanded a bit to proper shape), APS, LH2 chilldown pump fairing...

Later! OL JR

[luke strawwalker]

Started working on the Saturn I-F S-IVB stage detailing... Being the upper stage of the Saturn IB, it's somewhat different in details... And of course the interstage is markedly different.

Here's some pics demonstrating the differences...



Now I have to incorporate it all into a detail location wrap...
Later! OL JR

[luke strawwalker]

Got the detail location wraps done for the Saturn I-F (Saturn IB type) S-IVB stage...

And one for the interstage details including the ullage rockets...

Later! OL JR

[luke strawwalker]

Well, been playing with the Rocksim designs of these things... Still mulling over motor choices and stuff. Here's the Rocksim's of both the Saturn V and Saturn IF... the I-F uses Saturn V fins on the fairings, and Saturn I Block II fins between the fairings. Not sure if that's how I'll do it or not, though. May go with clear supplementary fins that plug into a pair of extra BT-20's installed in the motor mount, or something similar. I'm also still debating whether I want to go cluster or not. I may go with a single motor in both rockets.

Playing with the Saturn V, to use scale fins with a 5 motor cluster requires pretty massive amount of noseweight. To get the noseweight down requires the fins be VERY oversize, ruining the entire scale appearance of the rocket. Of course clustering also increases the risks of something going wrong, as well, for a couple seconds of "looks cool" with the five flames coming out the back, but it also increases the costs per flight as well. Eliminating the heavy cluster from the back greatly simplifies everything, allowing most of the noseweight to be ditched and allowing use of a single 24 mm motor in the center, with better looking faux F-1's surrounding it. It also allows the fins to be much smaller at the same time and still maintain stability margins. I could go with supplementary fins, either add-on clear plastic fins installed in 'dummy tubes" between the motors in the motor mount, sorta like clear flame fins or clear add-on fins similar to those balsa fins used on the Estes Mercury Atlas or the Estes Space Shuttle. One could even use clear 'slip on' fins like the Centuri? Saturn V did... but I'm still not sure...

I'm thinking about keeping it pretty close to scale and making it more neat for display while still being good to fly. This would mean keeping the fins smaller, and going with a simpler single-motor mount on both rockets, with installable twin faux F-1's on the Saturn I-F for display. That would greatly simplify prep and flying as well.

Still thinking-- Open to suggestions.

Later! OL JR

[luke strawwalker]

Decals... anybody got a source of 1/152 scale Saturn V and IB decals?? I'll need them both-- the Saturn V obviously and the Saturn IB decals for the Saturn I-F...

later! OL JR