REFLECTOR: engine size & CS prop

[Greg Poole]

I’ll check what was supplied to me and get back to you Lou
..hear Craig is
good for re-trimming the prop to get your take off rpm up
.but hey, you’d
know there’s no free lunch – you will certainly pay in top end (reduced
speed or higher rpm for same speed) to get the lower end performance


 

With two props (what luxury!) I guess you get to have one pitched for climb
and the other cruise performances (
if it were in fact practical to change
out for intended use)

 

Greg

  <mailto:greg at pooledresources.com.au> greg at pooledresources.com.au 

 

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Lou Stedman
Sent: Tuesday, 5 February 2008 11:25
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: engine size & CS prop

 

Just out of curiosity, what is the size and pitch you have for the IO-360?
Any one who is flying a Catto on a IO-360, I would love to hear what you are
using. When I  purchased my Vel, it came with two three blade Cattos. They
are both the same, 64-72. My problem is that I am not too happy with the RPM
I get on takeoff. The best I see is about 2300. If my engine is rated a 180
HP at 2700 RPM, then I am only getting about 75% power on takeoff. Is that
pretty normal? I talked to Craig Catto and he suggested that I send one back
to him to take out a little of the pitch but then I would have to run at a
higher RPM to get the same cruise. Just wondering what others are using.
Thanks for your input.

 

Lou Stedman
Velocity N7044Q
Olean, NY

----- Original Message ----- 

From: Greg Poole <mailto:greg at pooledresources.com.au>  

To: 'Velocity Aircraft <mailto:reflector at tvbf.org>  Owners and Builders
list' 

Sent: Monday, February 04, 2008 5:18 PM

Subject: Re: REFLECTOR: engine size & CS prop

 

Grigore,

 

What you have just asked about is EXACTLY what I am doing (thought I may
have said this in an earlier email on this topic). While there are some very
expensive fixed pitched props available, most are 18 to 25% (estimate) of
the cost of a constant speed unit such as the MT – depending on whether you
select 2 or 3 blade fixed.

 

I managed to obtain a second hand (never installed) Craig Catto 3 blade with
the IO-360 with extension unit that I was able to obtain from a US based
builder abandoning his 173 Velocity Elite project and have heard nothing but
good reports of the Catto prop in terms of performance and strength. Once
flying - dollars permitting, I will be then looking to get one of the “other
brands” of CS prop to get the best performance from such an efficient
airframe as possessed by our Velocitys.

 

Greg 

  <mailto:greg at pooledresources.com.au> greg at pooledresources.com.au 

 

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Grigore Rosu
Sent: Tuesday, 5 February 2008 09:01
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: engine size & CS prop

 

Greg,

 

How dificult/expensive would it be to transit from a fixed pitch to a CS
propeller?  In other words, suppose that in order to get quickly in the air,
one chooses a fixed pitch propeller (assuming they are easier to get, though
I'm not sure about that; they are obviously cheper though).  Then in 2-3
years, suppose that one realizes that one would really like to have a CS
prop.  Is it difficult/expensive to switch?  My question is probably very
silly; I really have never installed a prop.  I'm just looking for options.

 

Best,

Grigore

On Feb 4, 2008 3:28 PM, Greg Poole <greg at pooledresources.com.au> wrote:

For the same reasons I gave for going with the bigger engine, I would – if
the budget allows it – then go with a constant speed prop. I believe it is
generally acknowledged that a  correctly set up CS prop will enable you a
much wider performance envelope than what is possible going fixed pitch and
will consequently get you up to flying speed much faster than most fixed
pitches which tend to compromise  one end or the other (usually both!).

 

While the factory has favoured MT props to date, they are not universally
popular amongst Velocity drivers due to high service and purchase cost and
very soft blades which have proven easily damaged
as a consequence, many of
us await reports on other brands such as Vesta (how's it going Dave Dent?)
and the one Milt is promoting
. 

 

Greg in Sydney

  <mailto:greg at pooledresources.com.au> greg at pooledresources.com.au