(snip) it could have be great system to use, just pull Saturn Stage out storage put them together and launch them.sadly two killers waiting just around the corner to make a hit, one was the Space Shuttle, the other was cheap quick dirty Titan III-CAgainst both Modular aka Lego Saturn had no chance...
I have always liked the INT-20 alternative. Simple, elegant, relatively low cost (when production quantities are thrown in), yet retaining a good lift capacity. By changing the number of engines you nearly get a dial-a-rocket setup. Shut down the S-1B line to save costs, and build enough S-II's to continue to fly Saturn V as necessary. Shorten one or two LUT's to accommodate the INT-20 and save the others for Saturn V's. Lots of possibilities here that were never realized.
Had Shuttle program canceled and Titan IIIC explode in front of Member of Congress in 1966We could have today a Modular Saturn V with Payload range of 51000 lbs. to 862,000 lbs.
the reason they considered it was because they were facing some significant base-heating issues with only four engines. They were considering going as far as re-routing all the GG-exhausts into a central dump duct which showed some promise when it was decided that they would just add a fifth engine instead. Neatly sidestepped the base-heating issue which was therefor never actually resolved. A two engine configuration is actually worse and the two, three, and four engine designs had some significant engine-out issues.
The base heating issue --- I had never considered it before.
Using asbestos like that today would no doubt increase manufacturing costs.I must confess I initially ignored this interesting thread, because I thought it was about some Lego kit!
Of course they could have worked it out. There is no reason why 4 engines have to be spaced as far apart, so if you were willing to forego some Saturn V compatibility, it certainly could be solved.
Me too !How on Earth FOUR engines have base heating issues when FIVE never had and worked well ? Did the fifth, central engine carried all the heat away ? or was it related to the four F-1s firing longer, hence burning / melting the S-IC ? (surely enough, the tracking cameras show a very darkened Saturn V at stage 1 sep... )
I believe the base-heating problem arises principally from recirculation of the hot exhaust gases around the base of the rocket. It was less of a problem for the 5-engine S-IC because the central engine inhibited the accumulation of exhaust gas at the center of the base, AIUI.There are lots of papers on the subject on NTRS (which I've never read).I'm sure Boeing was well aware of the problem and had a good idea of how to solve it for the de-engined versions of the INT-20 and -21.