Hello friends,
after I've taken a look at the
LH2 Feedline again and comparing it with my Reference photos,
Source: georgesrockets.com (George Gassaway)
Source: NASA
I have decided to remove the rings that are too narrow (0,5 mm) and to replace them with wider ones (1 mm), which are much better corresponding to the original.
No sooner said than done! But when I measured the stub then after grinding off the rings, its diameter was instead of 3 mm only 2,7 mm, which I did not like.
That's why I took a rod Ø 3 mm and bent it under hot air according to my proven
Balsa-Bending-Technique.
But as it is sometimes, if one has not bent anything for a long time, this bending process did not go satisfactorily, because the lower balsa support behind the kink was too short, so that the kink of the rod was not bent exactly enough, but was slightly rounded as one will see.
I have taken this into account by a longer slope of the support and a more stable clamping of the rod, which has resulted in a more accurate bend,
what one can see in the following picture by comparing the two bended rods.
Above it are already to see the 1 mm wide rings, which I have cut off from a tube with Ø 4 mm, which I have previously drilled out to 3 mm.
Then I have filed the new stub to the required length and drilled a hole for the guide pin (Ø 1,2 mm),
and glued it in place.
Here the two rings have been pushed onto the Feedline, which I will glue with
MEK.
And so the new
LH2 Feedline looks like after fitting,
which I like much better now.
And now I could also adjust the
Feedline Brackets, which sit directly above the upper ring. But if one looks closely, one can still see a further ring directly below the
Umbilical Plate.
Source: forum.nasaspaceflight.com (DaveS)