REFLECTOR: Performance

[Peter Braswell]

Hi Geoff,
I'm still building, so I'm afraid I can't contribute much to helping you
find more speed, but I was wondering what you're doing for engine cooling.
 Do you have the newer style NACA ducts for engine cooling or do you have
the older scoop?  I understand that can make a significant difference.

I was also wondering about the prop.  I opting for a V/P MT three blade
hoping to be able to milk a little more top end.  Is your prop considered a
climb, cruise or climb / cruise prop?

-Peter
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*"It's a Jungle Up There": www.zuluworks.com*
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On Wed, May 8, 2013 at 10:38 AM, Geoff Gerhardt <geoff.gerhardt at gmail.com>wrote:

> 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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