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

[Jim Sower]

<...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 
>_______________________________________________
>To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
>
>Visit the gallery!  www.tvbf.org/gallery
>user:pw = tvbf:jamaicangoose
>Check new archives: www.tvbf.org/pipermail
>Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
>
>  
>