Repairing blades

[Bigpyro]

Is it ok to repair blades that have minor damage? I have 2 sets of blades for my Axe CP that have tears in the plastic film that covers the wood blades. Is it ok to glue these minor cracks and tears in this film? I do not see any damage to the wood underneath. When should you replace a blade? Both sets of blades have the damage from light blade strikes. Is it possible that they are cracked under the plastic film and I just can't see it? Sorry if this is a stupid question. I am a newb and have already made some rather expensive mistakes because I was afraid to ask "stupid questions"

[Aztek1701]

Hi Bigpyro,

No its not a stupid question the only way we learn is asking questions and making mistakes. Its cheaper to ask questions

Personally I wouldnt repair the blades, simply because of the possibility of a crack that you cant see.

It really all depends on what you call a minor crack or tear. In theory it should be ok to glue the cover back but if it was me it I wouldnt consider it unless it was VERY minor damage. You need to take some things into account before making a desicion .....

1st, the blades usually travel through the air at about 200 mph, this means that any gluing you do had better be aerodynamic.
2nd, if you add weight to a blade, you need to re-balance the set.
3rd the covering is partly there in wood blades to keep them together and to contain the bits if they break up.
4rth, the blades are probably the most critical and stressed item on the heli if you are repairing a blade, you need to ask ARE YOU SURE its right, cos if its not, the heli could be destroyed and you could be picking bits of blade / heli out of your teeth.

When you compare the cost of replacing the blades against, the cost of replacing the heli and maybe injuring yourself / others the point at which you replace blades becomes after very minor damage beacuse its just not worth the risk.

Hope this helps....; Azzy

[hawkman]

The covering needs to be removed to survey the blade properly....any cracks around the blade root (the hub end) then scrap the blade......any cracks from the hub towards the middle...scrap the blade

Blade tips? hmmmm a minor scuff is nothing to worry about....any minor cracks? you could use super glue to fill the crack and gently press together....but this would be a crack thats not more than 10mm long and with the grain...

Do flex the blade along its length when checking for cracks.....after a blade strike always shut down the heli and remove the covering....I had a blade that was badly cracked near the root....the covering was ok.....but this was after a hard landing when other things were bent up.

With blades that are deemed ok but need recovering? you could recover with new shrinkwrap or you could cover using sticky back vinyl/plastic as long as its nice and smooth.....you can lightly sand the blades....I mean LIGHTLY...and then varnish the wood.....but you will need to re check the balance of the blades.


Its a sensible question of yours........as Aztek said...theres a lot of inertia and loading on them thar blades


Rob

[uneverno]

The only stupid question is the one that doesn't get asked Me personally, for $ 15-20 a set for blades, why risk life and limb of heli or human? I'll concede it's a bit pricey compared to the total cost of the heli, until one considers the alternative

[Bigpyro]

Tonight I had a blade strike the leg of my table saw. The cover of the blade was torn, probably about a 1/4in tear. I decided to pull the cover all the way off of the blade and discovered the blade was cracked from the tip to the center of the blade, about a 4 inch crack. Thanks for the advice everyone. I sure am glad I did not try to repair the cover and use the blade.

[Aztek1701]

Hi again,

Its amazing how much damage can be done by what seems to be a minor touch. I forgot to say earlier, to give you an idea of how much energy is in the blades. I have seen a heli crash at a competition where a carbon blade fragment broke off about 10in long. The fragment was thrown about 200 yards before it embedded itself in a hillside. Imagine being 3 yards from that and in the path of it. YIKES

Take care.... Azzy

[hawkman]

The loads on a 30 size nitro heli can be quite something....the bolts that hold the blades in thier grips can be loaded up to 100 kgs.

Even a rotor thats winding down after the engine is switched off contains a lot of energy......never get in its way!!!!

Rob