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GM 17 x 8 Folding prop blades

Product Code: GM17X8
 (1 review)

Price: $33.37

2 in stock
Quantity

Description

Buy 3 sets of prop blades and get 15% off - applied automatically when checking out

A pair of very high quality GM 17 x 8 folding prop blades, suitable for HyperFlight's and other makes of folding prop yokes and spinners.

These blades are thinner (they have a higher aspect ratio) than normal folding propeller blades, allowing larger diameter blades to be fitted without pulling too much current. This increases the propulsive efficiency of the powertrain. They are also engineered to fold closer to the fuselage, and cause less drag when folded than other props. See photos 3 and 4 for a visual comparison of GM, RF and Aeronaut props, kindly produced by Andre Jeber Demetrio.

Note this product consists of two carbon propeller blades only. The central spinner/yoke assembly is not included. Also it is common for prop blades to not fit all spinner/yokes perfectly as supplied. It is often necessary to reduce the width the blade root slightly to ensure free folding movement. Also the cut out in the spinner cone often needs to be increased to allow the blades to fully extend. The root of the blade should not touch the spinner cone when the prop is fully opened.


GM 17x8 Folding Propeller Blade Specifications
Prop diameter 43 cm 17 in
Prop pitch 20.5 cm 8 in
Weight of two blades 12.5 g 0.44 oz
Width of blade root 7.95 mm
Size of hinge hole 3 mm

Reviews 1  


 Review by:

GM 17 x 8 Folding prop blades

These are beautifully designed and built prop blades that do exactly what is claimed -- they really do lay much flatter and closer to a fuselage than other prop blades. This reduces prop drag considerably.

However, there are two items that you should keep in mind when using these blades. First, because they have a higher aspect ratio (are narrower) than other blades, they do not produce quite as much thrust as conventional blades. This is not a problem, just be aware that you can use a slightly longer GM blade to produce the same thrust as a conventional blade.

Secondly, the spinner yoke that you use will have a significant effect on how flat and low-drag the blade lies against the fuselage. These blades are designed for straight yokes rather than the more common twisted yoke. While twisted yokes can be used with the GM blades, the blade will not be in as good alignment with the fuselage as it will be with a straight yoke.

An additional issue is the length of the yoke. In order for the blade to lay really flat against the side of the fuselage, the yoke must be short. If it sticks out from the spinner significantly, the prop will too, which defeats the intent of getting the prop to lay flat against the fuselage.

I know that I am being very picky here, but the main purpose of this prop design is to reduce drag and its effectiveness can be seriously degraded by a less-than-ideal spinner/yoke assembly. So if you want the lowest drag, pay attention to getting an ideal spinner/yoke.


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