Prop cycle

I’m within a few months of taking first flight in my -7. I have a zero time (well, an hour on the test stand, and maybe one taxiing) AeroSport Power IO-375 with tapered fin ECI cylinders (low compression), and a new Hartzell CS prop. I’ve started the engine and taxied a few times, while keeping rpm less than 1200 and CHTs less than 320. Watching to not glaze the cylinders.

How much rpm does in take to cycle the prop? I’m thinking I should run the engine, briefly, at full power before first flight. Test the prop cycling at this point? Want to make sure all is working, while not glazing the cylinders.

Thanks!

I can get mine to cycle (slowly) starting around 1400 rpm or so, 1700 for a good brisk cycle.

It really depends on the prop and the governor - I’ve had four Hartzell in service over the years, and all of them have had a minimum cycling RPM between 1800 and 1950 - mostly with PCU5000 governors, and one with an ancient Hartzell governor. The WHirlwind props we have all need about 1800 to cycle.

You really shouldn’t have any problem starting the engine, giving it a brief warmup, then going to 1900 and cycling the prop - it might take a couple of tries to fill the prop with oil, so don’t be surprised if nothing happens when you pull the lever(knob) the first or second time. Keeping the CHT’s at 300 or less is good protection - and that should be easy with a short run.

Paul

What Paul and Greg said.
FWIW, I have a different prop from you (MT) and Mt governor.
1800-1900 RPM will cycle, never tried lower.
There's a good chance you won't be able to run full power unless you tie down the tail.
With flaps UP and control stick fully back, I can't run above 2300 RPM or else the tail starts to lift at full fine pitch.
And then increasing pitch would only coumpoud the issue with even more "pull"...

The How of Glazing

Lots of views on glazing out there.

I am in the camp that folks who keep RPM and power low initially to prevent glazing are increasing their risk of glazing. I didn't start that camp, here is a recognized authority on that subject again with THEIR opinion:

https://www.aopa.org/news-and-media...ned cylinder,carbonized oil, known as glazing.

Min RPM to cycle that prop will depend on your equipment and possibly on your parts build that particular day they were assembled. For me 1700 can do it reliably at all observed DAs, as low as 1200 might do it depending on other variables.

Thanks for your replies, Everyone! I am using the PCU5000 Governor. I will continue to keep ground operations to a minimum.

I've had props overhauled and upon reinstallation on some have had to cycle them a number of times. The last one didn't catch till probably the 10th time at 2000 RPM
I even called the prop shop cause it was holding out on me.
Art