REFLECTOR: Power settings

[Chuck Jensen]

Pat,

With the CS prop, you control descent with RPM, not MP?  I do it a
little different.  With XLRG IO540 300, I leave the prop untouched after
setting at 2300, then I need only two settings; 15" or 11" MP.  15" will
allow me to fly the approach at 120kts w/gear up or 100 kts at 11".
This allows me to intercept the localizer at 120 knots and drop the gear
at (5 miles out/FAF/GS intercept).  That slows me to 100 kts, then MP is
reduced to 11" and a person slides right down the glide slope with
tweaking of +/- 0.5" MP to stay on GS.  Once on the GS and down to
100kts or less, then the prop will go in to full pitch, but it will make
no speed, trim or pitch difference which might upset the approach.

Gear-up
15 x 2300 = 120 kts 
11 x 2300 = 100 kts  
Gear-down
15 x 2300 = 100 kts  
11 x 2300 = 100x550 

These values are for one person and fairly heavy fuel.  With 2 or 3
people, a person might need to add another 1" of MP to maintain GS.
Using only two values, 11" and 15" MP keeps it simple---which fits me
pretty well.

Chuck Jensen


-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Pat Shea
Sent: Wednesday, May 16, 2007 1:13 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Power settings


Hi Al,

Glad to hear you're back in the air!

Hopefully some SE RG fixed pitch guys reply as well.

In my XLRG with an CS MT prop, it takes about 2,300RPM
to maintain 110KIAS with the gear down on downwind. I
pull the power back to 1,900RPM and slow to 90KIAS
once abeam the threshold. Assuming no significant
head-wind component, I pull back to 1,700RPM on base.
On final I slow to 85KIAS and adjust the power as
necessary (between 1,500 and 1,900 RPM) to maintain
the glide path. With no VASI/PAPI, I like to see a
decent rate of at least 500FPM on final - especially
if it's dark. On a short runway, I'll pull the power
over the fence and probably touch down around 75KIAS.
On a long runway a leave on a little power and still
touch down around 75KIAS. I'm guessing a little on
this touchdown speed - my head is out the window at
that point. 

FWIW, Pat

--- Al Gietzen <ALVentures at cox.net> wrote:

> I did a number of T & G's this past weekend, and
> found I was still searching
> a bit for power settings at various stages for a
> good stabilized approach
> and landing.  I thought it might be helpful to see
> what others have
> determined.  I realize the it will vary from case to
> case and different prop
> dia and pitch; but  - typical for an SE RG with
> fixed pitch prop:
> 
>  
> 
> Rpm for downwind, after pulling some power before
> turn to base, on base, on
> final???
> 
>  
> 
> Thanks.
> 
>  
> 
> Oh, yeah.  755V with 20B is flying again, and better
> than before.
> 
>  
> 
> Al



       
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