Robert Swaddling (Login N521R) HyperScale Forums 188.8.131.52
Jablo is wood
October 7 2010, 12:13 PM
Jablo blades are wood composite and were made by Rotol. The rusty red disc is the manufacturer's logo. I have a Jablo blade at my shop if you would like to see one. I also have a sawn off portion of a Jablo blade so that one can see how the wood was put together.
Here is a pic of the inside of a shattered jablo blade showing how it is built up and the thin veneer that covers it. It is all a very specialized process and very expensive today. The leading edge is thin brass. This is the trailing edge.
I also have a complete wartime blade off of MK923 (5J-Z).
So if one wanted to replicate the rear of the prop blades as worn down to the original surface (commonly seen on all propellers if they're used long enough), you'd create a wooden laminate finish first?
And I was surprised to see the leading edges are brass: the chipping seen in photographs on the blades seems to be silver not brass.
Props would not be allowed to wear down to the wood. Rotol made Jablo, Hydulignum and
October 7 2010, 3:03 PM
Weybridge Wood blades, all of which had a plastic covering over the wood. Wear tended to be at the front, and increased towards the tip, with the semi-matt black finish becoming dull, then possibly showing the brass l/e sheath. The blades were normally made under huge pressure, while gluing, which reduced the wood to about half its original thickness; after shaping, and sheathing, it was coated with a plastic "Rotoloid," "Rayoid," or "Schwarz" covering. Rotol's coloured disc was, according to them, pink, not rust, or could be yellow. Pink = Rotol wood, yellow = spruce or Douglas Fir, and the circle usually included further information, with two letters denoting the make-up of the blade, then a single letter signifying balance (3 or 4 blades, with the same letter, could be safely used on the same prop,) followed by a 4-figure serial no. Above the disc should be a set of yellow letters & figures, which gives the drawing no.
Yes the leading edge is brass and so if it got nicked you would see brass not silver. The one in my hobby shop is nicked up pretty good and you can see the brass but no wood shows.
My shop is Action Hobbies Kingsville and it is in Kingsville Ontario Canada. Right now I am home convelesing but would go in if you let me know you are coming in. >
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