I think “undercarriage” here has to be interpreted as “wheels” only.
It appears to me that none of the currently airworthy Ju 52’s and CASA 352’s have the original narrow, large-diameter wheels, using instead (smaller, wider) wheels with more readily available tires. Surely one wouldn’t have to change much on the undercarriage (e.g. struts) simply to mount different wheels?
Bit more than that – from the same SAA Historic Flight website….
“In the late 80s and early 1990s SAA experienced numerous problems with the ZS-AFA’s undercarriage, including non-availability of tyres. Many things were tried, recapping the tyres was one, until a supply of well preserved original tyres (They were “Phoenix Harburg”, if my memory serves me correctly) was found in Germany. These were shipped to South Africa, but after removal from storage deteriorated at an alarming rate, and their smooth surface, perfect for grass, bit the tar just too well and tore the by now 50 year old cotton strengthened sidewalls with alacrity.
Also this original arrangement featured the true Teutonic mantra of reliability through simplicity. There were no wheel bearings instead grooved phosphor bronze bushes were slid over the axle, if not greased every ten landings, or greased with a grease attacking the phosphor bronze they were prone to wear too (just like a Citroen Traction gearbox).
Eventually over time the axles were ovalled with wear too and investigation was made into repairing this problem. First new bushes led to a seized wheel on the runway. Next chrome plating of the axle was tried – this could not be done as Martensite or severe embrittlement had taken place on the big axle (which runs in one piece on this arrangement from the fuselage to the wheel). This had been caused by the heat control techniques used at production.
Next some original Ju 52/3m axles were acquired, but alas, the same problem lay with them. Denel investigated production of new axles, but this too came to nought as the original heat control techniques could not be replicated leaving the bend in the axle either too soft or too brittle. In the end the aircraft was parked in the SAA Apprentice Training School and remained un-flown for some four or five years until it was ferried to Swartkop in 1999. It then participated in one air show and remained un-flown again, until by the initiative of Captain Tony van Eeden the project was restarted in 2003 – the aircraft then being part of Transnet.
A chance look on airliners.net revealed a photograph of a Amiot AAC 1 Toucan at Duxford on static display, standing, as it were, on the solution! The revised Amiot undercarriage with the different axle incorporating wheel bearings, expander tube brakes and available tyres was perfect. A couple of phone calls later and a visit, the deal was done! ZS-AFA was jacked up, her main undercarriage removed, bar the “Kronprintz struts” (Junkers version of oleos) and sent to England.
A team from Transnet and SAA did the swop and within a few days the replacement undercarriage was at Swartkop waiting to be fitted. The most challenging was removing the wheel rims from the tyres, as the tyres had been pumped with solid rubber for display! A selection of hacksaws, kitchen knives and angle grinders did the job and after about two weeks we could send the rims and axles for NDI.”
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