REFLECTOR: Prop performance

[KeithHallsten]

I think he's referring to Paul Calhoun's XLRG, which has a 260 hp IO-540.  That prop has an 80-inch pitch.  Dave Dent's Catto was made with a 76-inch pitch, so it did better than the MT on takeoff and climb, but was limited on the top end.  I think Craig is going to build him another prop with a bit more pitch.  I may use his original prop on my XL FG, where the lower top speed will be compatible.
Keith Hallsten

  ----- Original Message ----- 
  From: Alex Balic 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Monday, November 08, 2004 10:34 PM
  Subject: RE: REFLECTOR: Prop performance


  Music to my ears AL- all praise Craig Catto!  do you happen to know the approximate HP that that 540 is making?
    -----Original Message-----
    From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On Behalf Of Al Gietzen
    Sent: Tuesday, November 09, 2004 12:14 AM
    To: reflector
    Subject: REFLECTOR: Prop performance


    I thought I would pass along this info from Craig Catto.  He had told me earlier that he had worked up a prop design (fixed pitch) on the 540 powered XL that was getting takeoff rolls only 100 ft more than an MT, climb rate not much less (don't remember the numbers), and as good or better top end.  I had sent him a couple of shots of my cowl and prop spinner with his prop; and he sent the following:



    We had another XLRG 540 fly with my fixed pitch prop over this last weekend... another gear up MT loss... Less than $3K and he was back in the air with my prop, extension and spinner.... figures were with full fuel, 1100 feet ground roll, 1300ft. min climb and TAS 193KTS!!.. average in runs in several directions... the owner was writing Duane a letter tonight...

    There are sure a lot of rotary conversion guys out there, so will be happy to hear how your runs... even static, let me know.. 

    Thanks,



    Craig Catto



    It seems to re-open the question of whether the nearly $10K and 30 lbs extra for the MT is worth it.  I guess the comparison also needs to be made at 5000 ft on a 90F day.  I don't know the conditions for the data above.



    The photos I had sent him are attached.  I was quite excited after running with the cowl and spinner on to find considerable greater air flow drawn through the scoop and radiator in the cowl than I had expected at idle and taxi rpm levels, especially with my 6" prop extension.  Hopefully won't need auxiliary fan.  On the next runs (which won't be until the end of the month) I'll rig a water monometer and measure the negative pressure.



    Al



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