enginehistory.org

[sbezman]

I recently started reading about the Dart turboprop. The author discusses layshafts with respect to the prop shaft gear reduction. What is a layshaft?
Is it like a quill shaft? Thank you.

Also, when will Mr. White's 4360 book be available? Thanks again.

[szielinski]

If layshaft means anything like the term in automotive gearing, it is a shaft through which power is transmitted but not drawn from.
That is, gears that impart a desired ratio to other gears, but are not a drive output on their own - they "lay" to the side of the main or counter shafts.
With a Turbo-prop, the turbine is driving the propellor as well as the compressor blades; and these are done at considerably different ratios. I suspect the layshaft imparts the lower ratio from the turbine to drive the propellor (I say 'suspect' as I have not seen a Dart exploded view).
May I also suggest perusing the link on the web-site here
http://www.enginehistory.org/gas_turbines.htm

HTH!