CONTROL LINE SCALE
SCALE STATIC PROPELLERS
By Fred Cronenwett | clscale7@gmail.com
IF YOU FLY in Control Line (CL) Scale competition, the propeller that you show the static judges is important. They will look to see whether you have matched the configuration, outline, scale size, markings, colors, and details against the documentation that you provide for the full-scale aircraft’s propeller. The only event class in which this would not play a role is Fun Scale. I keep the flying propeller on the model during static judging for this class.
The more common propellers that are used on World War II warbirds are three- and four-blade Hamilton Standard propellers. The full-scale aircraft you copied for your model might have used the Curtiss propeller, which has a completely different propeller hub and blade, so check closely. To be clear, the static propeller is only used during static judging and should not be to be used to fly the model.
Determine the scale diameter of the model’s propeller, and then match the diameter to the scale outlines on your documentation. Measure the model’s wingspan, and then use the full-scale aircraft’s wingspan to determine your scale factor. If you built a 1/8-scale model of the full-scale airplane, your scale propeller would be 1/8 the size of the full-scale propeller. If you are going to enter Profile, Team, or Sport Scale, the judges sit 15 feet away from the model, so some very small details do not need to be perfectly scale to get a good score.
The static propellers for my B-29 model needed some repairs, so I decided to make a new set. The hub was 3D-printed, and I purchased the blades. The hub design that I created was made to work with the existing collet
Fred Cronenwett
adapters that interface with the electric motor.
The 12 x 7 replacement blades that I used on these static propellers were sold by Flightline. They are intended to bolt into a hub, but I instead glued them into the static propeller’s 3D-printed hub. When you paint the hub and the blades, pay close attention to the markings and paint. If the full-scale aircraft had stickers on the blades, you will want your static propeller to have the same stickers.
I like to store the static propeller(s) in a box to keep them from getting damaged.
2027 F4B Team Trials
The CL Scale F4B Team Trials dates for the 2028 FAI F4 World Championships for Scale Model Aircraft will be announced at some point by the National Association of Scale Aeromodelers (NASA). If you are interested in being a CL Scale F4B team member, now is the time to get your model started for the team trials.
Scale rules, you have to understand the differences between the two.
You can enter your F4B model in Sport Scale at the Nats and fly the same model in the F4B Team Trials because they are two different competitions. You will have to fly the model differently for F4B since it has fewer options in the flight portion. Another key difference is that level flight is higher than the AMA Sport Scale event.
Martin Mars
I recently visited the Pima Air & Space Museum in Tucson, Arizona. It now has the Martin Mars flying boat on display. Flying boat models are allowed to have wheels added to the fuselage and wing floats so that they can be flown from a hard surface.
The Martin Mars has a unique shroud that covers the propeller hub, and the blade appears to be wider than the blades on the B-29. If you build a Martin Mars, the shroud could easily be 3D-printed to create the proper Scale look.
Contest Calendar
There are two more CL Scale contests in 2026 in which you can compete:
September 5-6; Aurora, Illinois
• Broken Arrow CL Stunt & Scale Contest: September 19-20; Buder Park, Valley Park, Missouri
Land softly!
SOURCES:
NASA
nasascale.org
FAI Sporting Codes
fai.org/page/sporting-code
Pima Air & Space Museum
(520) 653-4085
pimaair.org
