Hub Bar length

DangerBird

Member
Joined
Jul 17, 2004
Messages
90
Location
Barre, Ma
Aircraft
MuscleBee sold, Frankin-copter being built
Total Flight Time
175
Hello Friends, A quick question that has probably been talked over many times. What is the difference between 10' blades with a 4' hub bar and 11' blades with a 2' hub bar. Are they both considered 24' rotors?

Jay
 
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Vance

Gyroplane CFI
Joined
Oct 30, 2003
Messages
16,167
Location
Nipomo,California
Aircraft
Givens Predator
Total Flight Time
2400+ in rotorcraft
In my opinion both would be considered a 24 foot disk.

Speaking in the most general terms the blades near the hub are stalled. See page 16-2 and 16-3 in the Rotorcraft Flying handbook: http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/media/faa-h-8083-21.pdf

They would have a different blade loading.

In my experience there is more to rotor blades than size of the disk and chord.

Weight makes a difference in how they fly.

Tip weight makes a difference in how they fly.

Some are more efficient than others.

Some need a pre-rotator and some can be hand started.

Some are more inclined to flap than others.

Good luck with your project.
 

DangerBird

Member
Joined
Jul 17, 2004
Messages
90
Location
Barre, Ma
Aircraft
MuscleBee sold, Frankin-copter being built
Total Flight Time
175
Hello Vance, My reasoning is, if I buy 11' blades and 2 hub bars, I could change between 23' and 24' rotors saving about $2000. I liked the float on my old DW 24s. I also bought 23s from Ernie and found them a lot faster but more speed needed in take off and landing. Scott E had a Soma with 23s and he loved it
 
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