Just reading Tom Neil’s “The Silver Spitfire” book. At one point, he is directed into a soggy bomb crater and the a/c goes nose down, breaking the prop. Naturally shock loading of the engine is on the cards. My question is..how exactly was a Merlin tested for shock loading, in 1944, in the field?
Presumably nowadays there are more sophisticated methods…X-rays, ultrasound etc…but what about during active service in WW2?
By: MerlinPete - 19th April 2013 at 12:53
The figures quoted for the run out jig are 0.012″, but the jig amplifies the reading, so the true run out must be around half that.
Pete
By: TonyT - 19th April 2013 at 12:22
Stick a DTI up against it and rotate it. You will soon find if its not true.
Same with props, put something up close to the tip, steps, dust bin etc ;), mark on the object where the tip nearly touches and then rotate the prop and the other blades should hit the same spot.
A Merlin being geared as opposed to having the prop nailed directly to the end of the crankshaft will be a lot more forgiving than the latter.
By: slicer - 19th April 2013 at 11:05
Thanks….but how does one carry out a run out check? I’ve mislaid my Merlin Maint manual 🙂
By: D1566 - 19th April 2013 at 04:25
What was the tolerance for run out? Not a lot I would imagine …
By: Percypointer - 18th April 2013 at 20:54
just carry out a run out check on the prop shaft as described in TSD 292, Merlin maint manual. If all within limits, new prop n off you go..Obviously if its a great rate of knots, its game over..
Steve
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April 18, 2013 at 6:17 pm