Simple L-39 RPM Gauge question

Hi guys,

even while browsing the documentation, I cannot figure this one out. The RPM gauge of the L-39 has two needles tagged "1" and "2" ...

I am trying to understand what are those (considering that the L-39 only has one engine), but the documentation is vague about it. Here is the description:

ITE-2 (n1 pointer – HPC RPM, n2 pointer – LPC RPM)

... briefly what are those 2 needles exactly?

Probably a dumb question ... but can't figure it out sorry.

Thanks!

Hi, the l39 has one engine, but it has two stage. N1 tell the rpm for the low pressure conpressor while N2 give you the rpm for the high pressure compressor.

Both compressor are not connected by a shaft, therefore not turning at the same speed. that why you have two reading.

Or, in this case, if the manual say( I don't have that plane)

ITE-2 (n1 pointer – HPC RPM, n2 pointer – LPC RPM)

Then, N1 would be the high pressure compressor (HPC) and N2 would be the low side (LPC).

All the plane i know are the other way around.