Blades revisited. Dangerous shortcomings.

[barney]

A little bacground first. Recently at a Competition I had a blade root failure in flight which virtually destroyed my Trex 700 and could so easily have resulted in severe injury.

The Importer had the failed blades returned to the manufacturer for further examination including a 2nd set that were on a another model which were on the point of failure. I received a refund for the blades via the importer but not for the repairs leaving me to foot a very substantial repair bill. (circa £500)

Obviously I am far from happy at the outcome and due to this and recently spent a little time looking a little more closely at some of the 'used' blades kicking around my workshop just to see what we are getting and to be honest its all a bit scary.

The vast majority of Manufacturers need to up there game.

OK what did I find.
Blades not having a safety wire to secure the tip weight. Partially failed blade root (blade bush pulling through the root)
Inferior Hollow blade root design.
Pea-Podded blade after a leading/trailing edge bonding failure in flight.
Another had Carbon tows that were not wetted out with resin within the blade.

Even different size blades by the same company had differing shortfalls in design and construction. My latest is an 8 flight old set of blades with a poorly designed raised portion for root thickness cracking just outboard of the root.

This is to be frank is unexcusable and needs to be addressed or someone is going to be being maimed or killed.

[Steve]

No need to be coy here.

Name and shame please.

[3d_willz]

well to help people know what to look for what was the brand of blade to be wary of then.

[Made2Fade]

or pics...

[barney]

Blades I've had problems with. GLX 600, GLX 690 Extreme and Torsion 690 blade root problems. Torsion 600 Carbon, poorly bonded skins, Torsion Glass un-wetted tows internally.

IMHO poor design, Stepped roots design Torsion 690 and GLX 600/690. Hollow Roots, NHP 680 FAI, 680 Razor Pro's. GLX600, possibly 690's Some lack safety cables too.

Best I've looked at Radix, MAH, New SAB Trex 700 specific 710 blade. The Torsion 600 nice strong root and has a retaining wire, stiff but internally the tows were not wetted properly on the crashed one I looked at..well err into..LOL. Thing is different blades in the same range can be different for example the Torsion 690 stepped Roots on there 690.

It's well worth spending a little time cutting them open

[Steve]

Presumably all of these blades you've looked at have been crash damaged as well?

[jimheli]

have to say it would be nice to no .

[barney]

[tourerjim]

Although know what your talking about would be good to see pic's.

[barney]

Nope not all of them are crashed..but then again Its obvious some things are just plain obvious even in a crashed blade. For example Carbon Tows that are not wetted out..Pic no 1 is a failed root. Pic 2 was from a 2nd machine where the bush is being pulled through the Root.

[Steve]

Pic 2 was from a 2nd machine where the bush is being pulled through the Root.

Wouldn't the bush be towards the top of the picture if that was the case (i.e. nearer the main shaft)?

[barney]

This one is failing just outboard just on the step (uncrashed BTW. Pic no 2 above post is also uncrashed)

[Steve]

Ahh ok. What fish-scale-like blades are all these photos of?

[barney]

GLX Extreme 690 Carbons, GLX 600, next up is a Torsion 690 with 8 flights uncrashed

[trillian]

Well, I have thought often when watching 3D flying, about how these blades are tested for all the stresses put on them.

How the testing is done and how it is decided what factor over the anticipated stresses a blade needs to be engineered for. (looks like some are not anticipating the actual stresses put on them let alone allowing a factor over that amount).