Saturnial Prelude [1]

One of the items of my long list of to-do builds was the Rocketdyne F-1 engine in 1/48. And since the next big build will indeed be the Saturn V, I thought it appropriate to start the whole cycle with a little prelude; the building of an 1/48 F-1 without the heat shield blankets it had in flight.
There's only one F-1 that matters and that's Greelt Peterusma's F-1. Obviously intended to be part of an entire Saturn V rocket, Greelt never came further than the full S-Ic first stage, the J-2 engine and the interstage between the first stage and the S-II.
However, the model is legendary and I already once made one of his J-2 engines in 1/96. That was very doable and gave me the confirmation the F-1 certainly was able to be made in that scale. So tht will be integrated in the paper versin of the complete Saturn V later on.
Now it's time to do the big one. The F-1 is size-wise the biggest rocket engine ever built*. Modern technical advantages make engines like the Russian RD-180 much more powerful and fuel-efficient. Nevertheless, for its time the F-1 was a milestone in rocket engineering. And it still is an awesome beast to look at. So here's the first part of my 1/48 F-1 engine!

(full story after the jump)

*There was one engine planned that would've been bigger than the F-1 and that was called the M-1. But that was never made, because the rocket it was intended for, the immensely huge Nova, was cancelled.



I printed the F-1 on 200 grams paper but I immediately decided to use other paper alongside the regular white stuff.

The exhaust expansion skirt. this part was placed under the actual engine to get more impulse of the exhaust plume. This si how it originally looks, how it was designed. Lots of detail but no depth, unfortunately...

I got some aluminium and shiny silver coloured paper out for the detailing and I also kickstarted ye olde photoshoppe for some recolouring and detailing here and there.
I thought the engine bell's surface could use some more depth.

Some 2 mm wide aluminium coloured strips should do the trick.

I have a special double-barrelled Xacto for these kinds of jobs.

And this is how it looks after making all those tiny little lines stand out in aluminium paper. 176 little cuts and six long ones.

Inner section added. this part got a thorough recolouring.

The inner part, a cone with a smaller angle, also got more nuance. I used an actual photo of the fuel injector plate for the part depicting it.

Around the mid part of the engine there is this big fat ring shape. Inside, the used fuel of the turbo pump, not yet fully burnt, is pumped into the engine exhaust plume. Although it is fairly hot, compared to the actual burning fuel that is blazing out of the exhaust, it is relatively cool. So it is used to keep the skin of the exhaust cone a little cooler. Still unburnt it leaves the engine bell and protects the engine from overheating and melting. This is the dark exhaust matter one can see right under the engine bells on photos of the Saturn V when it lifts off the pad:

source: Arstechnica.com

And lastly, the turbo pump's coolant ring itself. it is made from shiny aluminium paper and I used aluminium sticky tape to make the 'welds' between the segments. This part is very asymmetrical and needs to be very precisely glued. I hope it all comes together when I finally glue the last and smallest part.
We'll see tomorrow!
Thanks for stopping by,
--PK

PS. Greelt's F-1 engine model and the rest of his Saturn V parts can be found for free at Jon Leslies Lower Hudson paper model store.