Some years ago I bought a compressor blade on ebay but I don't know which jet engine it's from.

Front view

Side view

It's quite light. I tried to determine the density by the help of my kitchen equipment and it's most likely made of aluminum. Density 2.something g/cm3. Not even close to titanium 4.5 g/cm3 - even considering my home made volume measurement;)

marking From one of it's markings (JR24660A) I found out the engine is from Rolls Royce. Other markings are:

5013 and 30815 (hand graved)

But I can't figure out the exact type. I read at wiki that old engines had indeed aluminum blades e.g. RB108. Pinhole in the foot might point to Conway or Spey? Unfortunately, good pics at Google are very limited for easy web research.

I hope someone can help me.

Thanx in advance ;)

  • 1
    $\begingroup$ Without all markings on the blade -- ideally good photos of them -- there's little chance of even narrowing down the engine family. $\endgroup$
    – Zeiss Ikon
    Feb 15, 2022 at 13:55
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    $\begingroup$ Should we ask why you bought a single compressor blade on ebay :D $\endgroup$
    – Jamiec
    Feb 15, 2022 at 13:59
  • 11
    $\begingroup$ @Jamiec the size of my desk is not sufficient for a collection of complete jet engines :) $\endgroup$
    – Rednose
    Feb 15, 2022 at 14:06
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    $\begingroup$ My guess it is a titanium alloy, not aluminium (little higher density than aluminium). It is probably an old engine, the past 20 years I've only seen dove tail joints. $\endgroup$
    – 0scar
    Feb 15, 2022 at 15:53
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    $\begingroup$ @Jamiec why not? I didnt get it from Ebay, but I value my Concorde engine fan blade quite highly amongst my collection. $\endgroup$
    – Moo
    Mar 4, 2022 at 5:26

1 Answer 1


It's a fan blade from a Rolls Royce Spey. The part number is also confusingly mentioned as a blade for an Allison TF-41 used on LTV A-7 Corsair II's but those blades appear to be different, and they have what looks like a little airfoil about halfway up the blade.

  • 1
    $\begingroup$ is the airfoil presence stage-dependent, or all stages would have it? $\endgroup$
    – Federico
    Mar 4, 2022 at 9:12
  • $\begingroup$ @Federico That's a good question. I could only find general pictures of the fans on the A-7 version and the Spey, not the other stages. I added an image link so you can see the difference. $\endgroup$ Mar 4, 2022 at 21:41
  • $\begingroup$ @Juan Jimenez Thanx alot for this information. The fact that the part no is is designated for Rolls Royce Spey and Allison TF41 makes totally sence. Both companies made the TF41 as co-desing based on the Spey engine. $\endgroup$
    – Rednose
    Mar 6, 2022 at 6:42
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    $\begingroup$ @Frederico The 'airfoil' on the blade is a snubber or clapper or part span shroud. This feature has several functions: it changes the natural frequencies of the blade to higher values, additionally it prevents the de-twisting of the blade during operation. It's normally used for 'long' blades with small chord length typically the fan / front stages compressor blades. Due to the aerodynamic losses recent engines use no snubbers but hollow blades with bigger chord. $\endgroup$
    – Rednose
    Mar 6, 2022 at 7:45
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    $\begingroup$ The "little airfoil" on the TF41 Fan Blade is the blade clapper. The TF41 Fan Blade part numbers were: 6869628, 6878181, 6897200, 6892422. $\endgroup$
    – user65732
    Oct 12, 2022 at 11:29

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