PROPS FOR CONTROL LINE SPEED
Four (4) props are made for FAI speed, all are proven performers and have held national records at one time or another.
Newest is the 6.4 x 6.2 SB. This prop has recently been used to rewrite all Australian records.
A fool proof starting set-up is an Irvine or Rossi, etc, and a 6 x 6 prop.
The 6.2 x 5.7 SB, 6.4 x 6.2 SB and 6.2 x 5.4 SB are square hub single blades suited to competition work. These props can use a specially machined counterweight spinner to suit the square prop hub
PROPS FOR CONTROL LINE AEROBATICS
By far the biggest success story of Bolly Props is the impact they have had on C/L Stunt. In many parts of the world, Bolly's dominate the top results , top 7 or 8 in 10 is not unusual. Bolly Props have been used to win at least two C/L World Champs and countless Walker Cups (USA Nats).
There appears to be three distinct 'set-ups', dependent on how the pattern is flown. In areas where an 'open' schedule is allowed, big prop loads dominate, as opposed to the 45 degree rule being observed on manoeuvre heights. The third set-up is the tuned pipe.
As with all models, the higher the diameter the more ‘pull’ , especially in vertical climbs etc. With C/L aerobatic models considerable attention must be made to forces of ‘gyroscopic precession’. See the ‘Propellers - Theory’ section of the book.
Whilst 2B props may give better vertical performance, the 3 blade prop will deliver a much smoother, more consistent performance - due to wind up suppression and lessened gyroscopic forces. For higher wind use, the 4 blade props are especially good at limiting 'wind-up'. High pitch props suffer more than low pitch props with the windy ‘wind up’ factor. The downside of low pitch props (unless being used at higher rpm ... =... pipe) is that they can lack ‘bite’ and authority. As with all things it is a compromise.
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