REFLECTOR: Performance

[Mike Dawson]

Did Catto promise 200 MPH or 200KTS. Your 160KTS= 184MPH. For a climb prop that is pretty good. Cruise prop will go faster but at the sacrifice of climb.
A constant speed prop will give you all around better performance but at the cost of $$$$$.

Mike
N104DD


________________________________
 From: Geoff Gerhardt <geoff.gerhardt at gmail.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org> 
Sent: Wednesday, May 8, 2013 9:50 AM
Subject: Re: REFLECTOR: Performance
 


Oops, all the speed numbers I mentioned are kts TAS, NOT indicated.  I cruise at 150ktas at 60deg LOP, and my max speed, full out is 160ktas.

My static is quite low, 2100RPM - Craig Catto has characterized this as a climb prop (66 x 74).

Geoff


On Wed, May 8, 2013 at 12:27 PM, Laurence Coen <lwcoen at hotmail.com> wrote:

 
>Geoff,
> 
>160 kias at 10,000 feet DA is 186 ktas or about 214 MPH.  175 kias at 
sea level on a standard day is actually slower.  Even 150 kias at 
the 10,000 ft altitude is 174 ktas and still over 200 MPH.  
You're doing great.
> 
>Larry Coen
>N136LC
>
>
>From: Geoff Gerhardt 
>Sent: Wednesday, May 08, 2013 9:38 AM
>To: Velocity Aircraft Owners and Builders list 
>Subject: REFLECTOR: Performance
>
>Folks, 
>
>
>I'm getting pretty consistent performance out of my 173RG over the last 8-9 
months since initial flight testing.  My question to you guys is, are the 
performance numbers I'm seeing typical, or should I be seeing better 
performance?  Normally, on a cross country, I'll fly b/w ~8-12,000', ~60deg 
LOP which typically has me going 150kias at 8-8.5gph.  Full power, 160kias 
is about my max speed.  
>
>
>I have a fixed-pitch Catto prop (66x74, design target 200mph @ 2800RPM). 
 When I'm doing 160kts, my prop is spinning at ~2800RPM.  That tells 
me that I have the power to spin the prop, but may have air frame drag that's 
keeping me from seeing the 200mph predicted by Catto at 2800RPM.
>
>
>I have a standard 200hp, Lyc IO-360, Lightspeed EI on one side, Mag on the 
other.  Timing as per spec for both EI and Mag.  About 90hrs on the 
engine (rebuilt).  Compression/oil consumption is normal.  Very stable 
performance from the engine.
>
>
>My plane is fully finished and pretty tight.  Main/nose gear doors are 
not hanging out and are reasonably well tucked in when the gear is raised. 
 Main wing angles of incidence are spot on, no rudder trimming was 
necessary to center the ball - she flies nice and straight.
>
>
>The factory predicts I should be able to cruise at 175kias - that's just 
not possible with my current setup.  Can others with Std Velocities relate 
the performance you are seeing?  Is this as good as it gets, or does anyone 
have suggestions for things to check to see if I can eek out a bit more 
speed?
>
>
>Thanks.
>
>Geoff
>
>
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