RC Tank Warfare community hobby forum

Ecam wrote: ↑Wed Apr 30, 2025 6:20 pm Great catch! Didn't notice that until you mentioned it. Other than having additional oil on the skirt, or that the lower skirt would have to be thicker for the ring lands.

It was the first thing I noticed when I saw the picture A wise old engineer once taught me that they were common on engines for that era, but really were not needed and fell out of favour as time moved on.

For pics of the original, try here:
https://www.researchgate.net/figure/Tig ... _263600207

I, too, did not think about the lower rings for oil control. Thanks to Tiger 6, we see how may rings were on the original. But--what ho!---look closely again; notice the blue glove on the guide from the connecting rod. I believe "Volunteer Les Wilkins" has three arms! Perhaps one could get an auxiliary arm or two for modeling.

So having reviewed the technical paper that the pictures came from, with a learned collogue...

As stated in the paper, the replacement piston was made from 2000 series Aluminium - great for light weight, high strength (i.e. aircraft structural grade), but the copper content also makes it high expansion - not a great thing for something subjected to heat while trying to maintain a close fit... Add in the total lack of wear resistance from the minimal silicon content and, erm yeah... 2 hours gentle running was about as much as you could expect

Today’s lesson is that just because you think that its easy to make a new part by measuring the old one, its really not that simple if you do not use the original materials and processes...

Metallurgy, is not a guessing game

HERMAN BIX wrote: ↑Thu May 01, 2025 10:56 pm Metallurgy, is not a guessing game

It's Voodoo...

HERMAN BIX wrote: ↑Thu May 01, 2025 10:56 pm Metallurgy, is not a guessing game

Truth.

Also going to add that my Metalurgist friend has yet to review and give me his comments - I expect something along the lines of "WTF were they thinking..."