REFLECTOR: Props and runway surfaces (was XLRG on grass)

Tue Jul 13 20:26:10 CDT 2004

Hi TEC,

I agree with you that a Performance Prop on a Velocity at gross is very
scary.  I ran one for awhile on my Velocity (Std Elite RG).  I then switched
to an MT.  What a difference!  Numerous times I have been loaded to 2400 lbs
and have had no trouble getting off the ground with about 2200 feet of
runway.  I agree with you that you should expect to loose about 4 knots on
the top end compared to the Performance Prop, but that is a good trade off
(I still get about 180 KTAS).  Also, I fly a lot of IFR and I feel a lot
better having the MT cut through the rain rather than the wood blades of the
Performance Prop.  It's also nice to have the climb performance of the MT
when you have to go missed.  I rely on my aircraft for regular x-country
transportation (MD to SC quite often) and I would strongly encourage any of
you that are planning the same thing to get proper equipment so that you
have a capable airplane.  Also, I have the counter-balanced Lycoming, so I
have not had any problems with fatigue cracking on the MT.  I have about 500
hours on the aircraft now (in 3 years).

Although I'm not happy about the price of an MT, I am definitely glad I
switched from a fixed-pitch prop.  Prior to the MT, I would not load the
airplane past about 2200 lbs and would not consider a runway less than 4000
feet.

Just my experience . . .

Jack
----- Original Message ----- 
From: "Jim Sower" <canarder at frontiernet.net>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Monday, July 12, 2004 12:54 PM
Subject: Re: REFLECTOR: Props and runway surfaces (was XLRG on grass)

> <...I have had the S*#T scared out of me with poor takeoff performance
> of my Velcoity/Fixed pitch...>
> I'm glad it's not just me.  I've found that the major factor in marginal
> takeoff performance is canard loading or CG.  The front seat design load
> limit is 400#, and my wife and I dressed to fly, with nav gear, etc. run
> between 450# and 475#.  We don't go at all at DA > 3500' or runway <
> 4500-5000' and that's a significant limitation.  By myself, things are
> MUCH better.  Must be noted that I don't have wheel pants (yet), but I
> don't think that's significant at takeoff speeds.  The big thing is
> loading the canard to where at liftoff it's sort of "on the back side of
> the power curve" - huge induced drag, not enough excess thrust to climb
> or accelerate.  I find that if I have the runway, and can accelerate to
> 90 kts or better before rotation, things go much better, but at high DA,
> it takes a LOT of runway to get to over 90 kts.
>
> <...I climb 200fpm less (below 120kts, the same at or above) at most
> with the Performance, and actually cruise faster (less blade area in the
> wind.) ...>
> I had assumed CS props were a lot better at climb and cruise too.  Looks
> like I'll be passing on the CS for good now.  The extra money seems much
> better spent on more engine for takeoff.  Turbo 13B or NA 13B at 8000
> rpm is sounding better and better.  Save $10k - 12k on the engine and
> another $10k on the prop.  In the unlikely event I can ever fly it to
> TBO at 300 hrs a year, I can rebuild it for under $1000.  That's
> attractive to me.
>
> Thanks for straightening me out on MT cruise performance ... Jim S.
>
> HYTEC45 at aol.com wrote:
>
> >In a message dated 7/6/2004 8:06:03 PM Pacific Standard Time,
> >davedent at comcast.net writes:
> >I had a long talk with Catto today.  It was most interesting.  When he
gets
> >back from France he and I are putting together a test.
> >
> >I flew my STD-RG with a Performance prop for 400 hrs.  Now I have the mt.
I
> >am no fan of mt.  With my experience flying both on a Velocity, let me
share
> >this (IMHO).
> >
> >The only need for the constant speed is takeoff; period....  The mt is
NOT
> >the best cruise prop. Once I'm at 100kt +, I would much rather have the
> >Performance on.  I climb 200fpm less (below 120kts, the same at or above)
at most with
> >the Performance, and actually cruise faster (less blade area in the
wind.)  I
> >burn less fuel with the Performance because I have to pull out about 1"
MP to
> >cruise at 2600rpm, which is 3kt faster than running the mt @ 2600 and
full MP
> >(above 8000ft.).  You guys that like to cruise at rated rpm will probably
> >burn the same as the mt, but with an additional 3-4kts (I personally like
to stay
> >below rated rpm as turbulence can really bring on the unexpected
momentary
> >rpms.)  I can be assured the fixed pitch will probably still work to fly
me home
> >when I'm far far away.  I would in no way take my mt from Calif to
Oshkosh,
> >again.  Over the 200 hrs I have put on my mt, it has averaged 34 hrs of
> >operation between failures that put it out of operation, and required
dissambly to
> >repair. If I wanted to go to Oshkosh, I would just put the Performance
back on.
> >I am right now watching signs of separation between the SS leading edge
and
> >the wood blade on two of my blades (yes I have stayed out of the
restricted rpm
> >range), and grease leaking from all three blades after mt "modified" my
hub
> >to prevent grease leaking (had none before modification), and it's return
for
> >re-sealing.
> >
> >I'm sure Catto can get the most out of the prop in cruise, and an
acceptable
> >climb at speeds higher than Vx & Vy.  If you can push that pig off the
line
> >with a fixed pitch and still maintain a somewhat manageable takeoff
distance (at
> >full gross remember); I'll be in line with a check.  I have heard many
good
> >things regarding the Catto Props, but I don't have one, just the
Performance.
> >With the fixed pitch prop, it's like trying to leave the line in third
gear in
> >our car.  Horse power is directly proportional to RPM.
> >
> >I have had the S*#T scared out of me with poor takeoff performance of my
> >Velcoity/Fixed pitch.  That's why I reluctantly moved to the mt.  Anyone
who is
> >flying with a fixed pitch that says they have not had a "pucker factor"
or two,
> >has not been around with there Velocity.  My IO360C has Lycons 10 to 1's
and
> >puts out over 200hp.
> >
> >I'm very intrested in a mt replacement, and a fixed pitch design would be
a
> >extra bonus.
> >
> >TEC
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> >
>
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