Constant speed prop how to use.

gsimatos · Post by **gsimatos** » Sat Feb 03, 2007 4:53 pm

can anyone give me the basics of how you use a CS prop? I understand it is like having 4 gears as opposed to 1. How do you use it for takeoff, cruise and to slow down. Does the prop control only pitch or does it hunt for a certain (constant) speed??You guys keep telling me 'no dumb questions', mabe this is a little basic but I think understanding how something works makes it easier to use and better to appreciate the benifits of the CS prop. Thanks Gary

jim_geo · Post by **jim_geo** » Sat Feb 03, 2007 5:45 pm

That's a good question. I wondered about the in's and outs of CS props myself. One of the things I've heard from people that have gone from FP to CS is that they feel as if they're flying the prop and not the plane.

captain_john · Post by **captain_john** » Sat Feb 03, 2007 8:15 pm

SIMPLE! Push the blue knob forward and the engine speeds up! There ya go!

In all seriousness, get some time in an Arrow or something. Having a constant speed prop is alot of fun, I think! I enjoy all the bells, whistles and things that go WOO WOOO!

A blue knob just keeps things interesting!

Now, in order to get a checkout in a complex airplane you will NEED to read this article by John Deakin. It is called Those Marvelous Props

http://www.avweb.com/news/pelican/182082-1.html

In order to read anything on www.avweb.com of value, you will need to become a member. It is free and easy, so why not.

His stuff is AWESOME and there are several other articles you will need to read as well such as Manifold Pressure Sucks and Mixture Magic.

Let me add a little bit more to this in my own way. Keep in mind that I am no Deakin or a CFI, but simply a layman.

Do not think of the CS prop as "gears". It doesn't translate well that way. It is simply a variable pitch airscrew that can go fine for takeoff and coarse for cruise.

In answer to your question, yes... it DOES maintain a "constant" speed for whichever RPM you select. That is, until you start to reduce power to the point where the enine will not maintain the preset RPM.

Is this a good start?

Gary, what is your piloting experience? How many hours and what types of aircraft have you been flying?

CJ

gsimatos · Post by **gsimatos** » Sat Feb 03, 2007 9:28 pm

Thanks you guys. Yeah it seems to me there must be more to the CS prop than the changing gear description. My flying experience is around 250 hours first doing my liscence in 172s and 152s. I then got a cessna 170 (see the gsllery for a pic if ya search cessna) and most of my time is on that which is a fixed pitch prop set up.Oh yeah 3 hours in a RV6 with 320 and also fixed pitch. I am getting my feus and wings this week and starting to think about the firewall forward issues, which eng and which prop. Several guys around here have RV6 and 7 and some like the 320 others have the 360 engine but all have the CS prop and like it so I want to get educated a little so I can focus on a prop and engine combo. I will check out the above webs sights too Thanks again Gary PS any guess what a QB feuselage uncrated would weigh????????G

captain_john · Post by **captain_john** » Sat Feb 03, 2007 10:10 pm

A QB fuse uncrated could easily be handled by 3 people only because it is ungainly. Two people could pull it off if need be.

I would guess it to be about 150 pounds or so right out of the box.

I am going to guess the next question, and it isn't a dumb one. You are wondering if a CS is for you!

I say, it is of you want one!

CJ

gsimatos · Post by **gsimatos** » Sat Feb 03, 2007 10:46 pm

CJ thanks Regarding the CS prop you alway hear folks talking about the grreat climb but something else that strikes me is alot of guys comment on the ability to put on the "brakes" like ya might do for your landing. Going from cessnas to a very slippery plane like an RV I would think youwant lots of options to slow the darn thing down. My cessna 170 has only broke the sound barrier a couple of times but the odd time when I am landing I come in a little quick and no matter how hard ya pull back the throttle you cal only your flaps to help slow down. Of course the answer with the 170 is set it up for what ya want in terms of spped correctly. Semms to me the CS prop just adds another level of speed control in the most critical phase of flying ie landing . That is if I understand how you use it Thanks again and I will find a 3rd guy for my feuselage Cheers Gary

jim_geo · Post by **jim_geo** » Sat Feb 03, 2007 10:48 pm

I can tell you from having picked up my own QB fuse from the factory and bringing it home. They are light and very easily handled by only two people.

captain_john · Post by **captain_john** » Sat Feb 03, 2007 10:56 pm

Typically when you are on approach to an airport you will set the prop for go around pitch. What I mean is that in the event of an aborted landing you will need takeoff power and RPM's for the subsequent launch.

You won't be using the the prop to slow you down when on approach.

You will want to manage your descent while inbound to the field just like any airplane. I still have under 10 hours RV time, but my experience with RV's other makes tells me that the RV will take a little bit of time to slow down just simply because it moves along so fast.

CJ

captain_john · Post by **captain_john** » Sat Feb 03, 2007 10:58 pm

Jim, I am guessing that you have a healthy back.

When we flipped Wicked Stick's fuse, I was pretty happy to have the tailwheel! My back is JUNK!

CJ

jim_geo · Post by **jim_geo** » Sun Feb 04, 2007 12:33 am

Well also there just isn't anything to the QB. It really is just a shell. Once you take everything Van ships inside the fuse out it's pretty airy.

gsimatos · Post by **gsimatos** » Sun Feb 04, 2007 12:56 pm

All of you thanks
CJ I got onto the site with the John Dekins article and plowed thru the Marvelous Prop article. I think this is just what the doctor ordered and he writes in an interesting way. I think my 40 watt bulb in my brain is starting to light up regarding the workings of the CS prop. This site sure is a gold mine of goodies for the aviation nut so thanks for that also Cheers Gary

captain_john · Post by **captain_john** » Sun Feb 04, 2007 1:34 pm

Gary, you are welcome!

It IS a gold mine, isn't it!

Read everything Deakin says and treat it as gospel. He is a WIZARD!

After you read those 3, Putting it all together is where the rubber meets the road... er or more appropriately, where the wind meets the wing!

I am reading them now for yet another time. It seems like each time I read them, I get something new out of it!

CJ