REFLECTOR: Performance

[Geoff Gerhardt]

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 <geoff.gerhardt at gmail.com>
> *Sent:* Wednesday, May 08, 2013 9:38 AM
> *To:* Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> *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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