Recommended Rotor Blade Diameters

The rotor blade is the lift-producing airfoil system for a rotorcraft. A rotor blade "set" includes two rotor blades and a center section. The center section is sometimes referred to as a hub bar.

It is important to select the appropriate blade set diameter (length) based on the maximum loaded gross weight of the rotorcraft.  The maximum loaded gross weight includes the weights of the rotorcraft, pilot, passenger (if any), fuel, oil, and baggage. It also includes the weight of the rotor system (the approximate weights are listed in the chart below).

Rotor System Set Diameter (Length)
Approximate Weight
Loaded Gross Weight Minimum
 Loaded Gross Weight Maximum (1)
23-Foot (701cm)
62 lbs. (28 kg)
550 lbs. (249 kg)
625 lbs. (283 kg)
24-Foot (731 cm)
65 lbs. (29 kg)
575 lbs. (260 kg)
680 lbs. (308 kg)
25-Foot (762 cm)
68 lbs (30 kg)
600 lbs. (272 kg)
740 lbs. (335 kg)
25-Foot (762 cm) (2)
77 lbs. (34 kg)
600 lbs. (272 kg)
740 lbs. (335 kg)
26-Foot (792 cm)
80 lbs. (36 kg)
700 lbs. (317 kg)
800 lbs. (362 kg)
27-Foot (822 cm)
83 lbs. (37 kg)
750 lbs. (340 kg)
860 lbs. (390 kg)
28-Foot (853 cm)
86 lbs. (39 kg)
800 lbs. (362 kg)
1,000 lbs. (453 kg)
29-Foot (883 cm)
89 lbs. (40 kg)
850 lbs. (385 kg)
1,200 lbs. (544 kg)

(1) The maximum loaded gross weight includes the weights of the rotorcraft (to include the rotor system), pilot, passenger (if any), fuel, oil, and baggage.

(2) The 25-foot diameter set normally comes with a short (3-foot) center section. Experienced pilots have stated the 25-foot set "flies even smoother" with the long (5-foot) center section. Skywheels has not made any verification of this claim and therefore has no basis upon which to confirm or deny such a claim.

Rotor Blade Tip Ends

Skywheels offers two different style tip ends.  One style is called a square tip and the other a swept tip.

Teeter Block Heights For Different Diameter Rotor Systems

The center section includes metal teeter blocks of various heights in the middle of the center section. The teeter block heights, along with an adjustable barrel, physically attach the rotor system to the rotorcraft's rotor head. The rotor head teeter bolt, sometimes referred to as the Jesus bolt, must match the height of the barrel in the teeter block heights. In addition, the stop plates for the center section and rotor head must make contact at the correct rotor blade tip angle. If the stop plates don't make contact at the correct angle, the operator may incur a blade strike with the ground during taxi, takeoff, or landing. A Skywheels representative will be of further assistance.

The heights of teeter blocks are those that we have found most desirable over the years for operators flying at or near sea level, as well as for elevations at or above 5,000 feet above sea level. Optimal teeter block heights will reduce control stick oscillation.

It is important to note that every application will present a slightly different optimal teeter block height requirements. Disc loading and altitude make a big difference in making this determination. We have made available a variety of adjustable height teeter block spacers that have been very helpful, especially on the longer rotor systems of larger aircraft.

When a teeter block height change is made, the rotor head towers must also be changed accordingly. When ordering Skywheels rotor systems, we will ask questions about your current rotor head setup and have you take a few important measurements so we may closely approximate the rotor blade tip angle using Skywheels rotor blades.