REFLECTOR: Performance

[Mike Dawson]

Geoff,

I believe you are correct. Cato refers to the SE wing not the 173. Now the question becomes wether you are satisfied with your climb and speed or if you want Craig to crank in a few more degrees of pitch. Like I said 160 KTS on a climb prop is not bad with your wing.
By the way I have enjoyed your videos. Nice work.....nice plane!

Michael E Dawson
ATCI CFII


On May 8, 2013, at 7:53 PM, Geoff Gerhardt <geoff.gerhardt at gmail.com> wrote:

> Mike,
> 
> I'm not sure Catto makes any promises, but that is simply the design spec based on a Velocity powered by a 200hp engine.  It was 200mph at 2800, not 200kts.  Catto may be stating that based on a Velocity SE-RG, not a 173 like I have.  That is the basic question I was looking to get answered.  Is 160ktas top end what I should expect from a 173RG.  I've heard that SE-RG's will see 175ktas, but it is sounding like the 173 wing does have more drag and it may be that 160ktas is typical for a std Velocity with the long wing.
> 
> Geoff
> 
> On Wed, May 8, 2013 at 5:55 PM, Mike Dawson <medawson250 at yahoo.com> wrote:
>> 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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> 
> _______________________________________________
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