1st time with a CS prop
 

Next week I'm going to be flying a C-206 in SE Asia for a few hours. This will be the first time flying a 6-seater and using a CS propeller. I understand the theory (I think), but are there any tips for the first time? What did you find strange/different the first time you took 'a step up'.

Moving to a CS prop, save for the need to include RPM settings in your checks, is a bit of a non-event. There maybe some issues regarding full power in relation to RPM setting. Some (I imagine all) types generate tremendous torque and hence strain on the crank if full power applied with cruise RPM settings. Something to be aware of for climbs as well as the usual general handling and go-around scenarios.

Just be sure you understand the PoH, especially for procedures regarding run-up checks, prop and power combinations, forced landings and prop overspeeds.

The basic moves to remember are 'Throttle back' and 'Rev up'. Which translates as: When reducing power retard the throttle first, and then the propellor control. When increasing power select full RPMs first, then increase the throttle setting. I found this in a very old manual years ago and somehow never forgot it. It sometimes comes in handy still ;)

This is a basic rule of course so be aware that your POH is the final authority on engine handling.

Sans

The first few times I flew a CS equipped a/c, I tended to reduce the power and monitor the rpms, instead of the manifold pressure!

I couldn't understand why the rpm stayed the same, but the climb performance went to !!!!!!

Fortunately th epenny dropped after a couple of seconds :}

further to Jhieminga's advice, there's a simple rule:

Keep the prop on top !

Translation: if you always keep the prop lever closer to the panel than the power lever when making any changes to your settings, you'll be fine!

Be gentle! And that's about it. There's no special magic.

The only issue I had was, if I had been in cruise flight at altitude (6-10,000ft), to remember to constantly reduce prop pitch as you reduce altitude; if you don’t the manifold pressure will increase beyond the recommended.
Regards,
W.B.

White Bear

Do you mean reduce power with throttle?

By reducing RPM with prop lever you increase the manifold pressure in a normally aspirated engine.

Its a good thing to do (reduce RPM) when you start a descent...especially above full throttle height to put more load on the engine. Other wise its like riding a bike down a steep slope and trying to peddle, your legs go flat out bouncing around the place and may cause damage to your muscles!
:}

But of course as you loose more height you will need to reduce MAP to keep it around the desired cruise/descent setting.

regards 1M

SA there is a fair bit of uninformed drivvle being spouted here.

Go Pelicans Perch and scroll down the page until you see on the right hand side 'Engine Related Topics'.

Read Manifold Pressure Sucks, Those Marvelous Props, Mixture Magic and Putting it all together...in that order.

I highly recommend the rest of you do it too:ok:

I have about 7000 hrs sitting between or behind constant speed propellers systems and own one bolted to the front of my Bonanza...what John says in these articles is absolutely the best information you will ever read on this stuff...I also have the Gami injectors and EDM 700 engine monitor and run 'WOTLOPSOP' which you will read about too.

The engine prop combinations he is discussing in these articles are exactly the same as what you will experience in the C206...Continental IO520 or IO550 and a Macauley 2 or 3 blade CS prop.

Chuck

Chuck,

A good informative read there, nice one. Yet to fly a C/S prop aircraft, but i now have a good idea how it all works for when I do next year.

Lots of other interesting articles, just need the time to read them all!

J

Maybe it won't matter so much in Africa, but if you fly a CS prop 'over here' you can make a great contribution to lower noise levels on the ground by doing the circuits at a reasonably low RPM. I usually run at about 2100-2000 RPM a couple NM before the airfield and stay on that setting until short final crossing the fence.

I live at 2NM final from my airport and some pilots seem to need 2700RPM just to get around the circuit.

Chuck,

A good informative read there, nice one. Yet to fly a C/S prop aircraft, but i now have a good idea how it all works for when I do next year.

Lots of other interesting articles, just need the time to read them all!

J

Just got back from Thailand and for a number of reasons, didn't make it up in the air at all.

Still, thanks for the replies (esp Chimbu - what a good site that is and I could read John Deakin all day, if only my boss would let me!)

Am I not correct in thinking that you need to get type aproval if you have not used a VP before? So in that case you have to get an instructor to sign you off before you can fly it.

Funfly.

You only need "differences training" from a qualified instructor and a sign-off in your logbook.

Even flying first is not a requirement although in many opinions would be a good idea.

BTW, "differences" is also required for Tailwheel, Turbocharger, retractable gear and pressurisation.

Enjoy.
Sleeve. :ok: