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Advanced Technology Products Rotor Blades.

You will have seen elsewhere in this newsletter that Galtech Models Ltd are importing ATP Main Rotor and Tail Rotor blades, and have also kindly donated two sets of these blades to the Club.
So I was keen to try out these blades for myself to see what two “Collective Pitch” subscribers would be receiving.
Thanks to Galtech Models for supplying a sample to appease my curiosity!

The Review - Part One.

The Main Rotor Blades :

My Concept 30 SRX uses 520mm rotor blades with 3mm root and ATP have a blade that fits the bill. (SP30S 520mm Symmetrical) The main rotor blades are laminated wood, consisting of five layers of lamination. They arrive “pre finished”, this means that the root reinforcing plastic grips (for want of their technical name?) are installed (glued and screwed in place), and the blades are covered in a clear plastic “heat shrink”. The finish is absolutely smooth, flat and even, and sealed at the ends with no “daggy” bits. At first glance I thought the blades were coated with clear lacquer!

Being septic (sceptic), and with the weather totally abysmal for flying, I amused myself on a wet Sunday by checking the blades on the balancer. The main rotor blades have identical C.of G. as close as I can measure, i.e. less than 0.5mm difference. The actual C. of G. point is 14mm further toward the tip than my FunKey glass blades, so that should help with auto’s, should anyone be silly enough to turn off their perfectly good engine .

On the beam balance, the two blades sit horizontal (i.e. in balance), so any tracking tape I attach to one blade will have to have a similar piece of tape on the other blade, they are “that close” out of the packet.

I’m stuffed if I know how they put the weights into these blades, as there is no visual evidence of there being any weights in there at all. However, the weights are there nevertheless (maybe added during the laminating process?) as borne out by the C. of G. being nearer the tip than my glass blades, and also, I hear that Rene from Galtech, who also didn’t believe the blade was weighted, chopped one in half to prove that the weight was in there. (like “how do they get the caramel inside the chocolate”?)

The tip of the main rotor blade is curved, unlike some wooden blades which have a “square cut” tip. In fact the tip shape is very similar to my glass FunKey blades.

The Tail Rotor Blades :

These are ATP TR97 tail rotor blades, and look like a cross between a Samurai dagger and an agricultural implement. They are plastic and are moderately flexible, so should withstand the occasional “earthmoving” tail down landing on a farmer’s rough cow paddock! The length (root to tip) is the same as my plastic Concept tail rotors, and the width is also the same, they just have a weird shape!

From the photo, you will see that the root is a big six sided hole. You are supplied with two sets of four “half washers” that fit into the hole. One set is for a 4mm blade holder, the other is for 5mm. My Concept uses 5mm tail rotor blade grips.
The point of having a “rotatable” insert at the root, is that, according to the instructions, you can alter the tail rotor blade CofG. (chordwise) configuration, as the root bolt hole is offset within the washer. (It’s easier to see than describe...) To be pedantic, the “CofG” of the blade is unaltered, it is the pivot point that you are altering. With the washers rotated so that the bolt hole is near the leading edge, the blade has “quick” response, at the middle position the response is “normal” (?), and when the bolt hole is near the trailing edge, the blade has “slow” response so the instructions say.

After removing the washer from the molding tree, it “snaps” into the root hole in a positive manner. However, the two half washers “pop” out easy enough if you want to rotate them to a new position to try out.

The Review - Part Two.