can anyone explain the logic behing this humungous nosewheel?
especially as rubber was a scarce material in ww2 germany
According to Marek Rys and Marek Murawsky on page 160 in their book
Horten Ho 229 (Monographs Special Edition in 3 D) the Ho 229 nosewheel was the tailwheel of a Heinkel He 177 bomber, and during taxiing the nosewheel bore nearly half of the aircraft's weight.
From drawings in this book it is clear that the nosewheel was not rotated 90 degrees when retracted. When retracted it sat behind the cockpit.
From page 170 of the same book: the main landing gear wheels were from a Bf 109 G.
All three wheels were retracted hydraulically and lowered by gravity force.
I think they may be wrong about the He 177 tailwheel. According to Guenther Sengfelder in German Aircraft Landing Gear, the He 177 A-1 tailwheel was 780 x 260mm, with later models having an 875 x 320mm tailwheel. The nosewheel of the Ho 229 was 1015 x 380mm - see attached drawing from German undercarriage manufacturer Kroenprinz from August 1944. That's not to say that the tyre was bespoke - it may well have come from something else - but it probably wasn't an He 177 tailwheel.
It's also been suggested that the nosewheel came from the main gear of a B-24. But that was evidently 56in in diameter - which I think would make it too big.
The main landing gear wheels were from a Bf 109 (mark unspecified), as noted by Reimar Horten in his March 1, 1945, project description (see also attached). Evidently the plan for the series production model was to use the main wheels from an Me 262 instead.