Align Engineering

[10x]

Just as a side note KDE do upgrade arms which are wider giving more leverage but still have the same length bolt, better quality but not shouldered. But I do not know how deep the holes are drilled in the arm compared to the Align part.....

[coolice]

Im useind the exact same longer align blades as alex was using and I don't constantly load the model when I fly (in fact I put a mid flight blades stop into that flight aswell) I fly loading and unloading. So I don't think blades folding slightly will cause this!! Well I guess we all hav our own opinions, jus don't wanna see someone have a failure due to not using a longer bolt that could have easily been swapped out. That's all I have to say

Hey.

Unfortunately you could have multiple flights with the right ingredients to help a boom strike and not have one, then one day put the model/rotor rpm/blade pitch at just the right point and boom.
Anyway we're drifting off topic for no reason as it has no relevance here. Theres is a video on HF where a guy performs the same manoeuvre as Alex did and boom struck also, slow motion video tells the story.

With the bolts, bottom line have you had a failure here? If not then while the numbers are not ideal for proper screw to aluminium practice, in flight its not causing a problem.
As above be aware any screws added without a shoulder under the head could mean a weaker screw head, as the screw cut portion of the bolt now goes to the underside of the head, reducing the diameter of the bolt and it's strength.
Ideally a longer shouldered bolt is required, but this is immaterial if the thread it goes into isn't deep enough to tqke full advantge of the change.

[waveydavey]

Are we not talking about 2 different fixings here. The bolts Gixxer is referring to are the 2 that hold the arm to the blade grip and not the shouldered ones that hold the link to the arm.

Not sure what you mean about the shank length, Ive never seen a 3x6 bolt with an unthreaded portion. Not to say you can't get them but not seen any.

[10x]

The actual bolts we are talking about from align are M3x6 shouldered bolts, granted not a very long shoulder......



700 DFC Main Rotor Holder Arm H70095 - ALIGN-TREX.co.uk RC Model Helicopter Specialists in ALIGN, E-Flight, Blade, Goblin, Synergy, ALeeS, Outrage, ELY-Q

[coolice]

Are we not talking about 2 different fixings here. The bolts Gixxer is referring to are the 2 that hold the arm to the blade grip and not the shouldered ones that hold the link to the arm.

Not sure what you mean about the shank length, Ive never seen a 3x6 bolt with an unthreaded portion. Not to say you can't get them but not seen any.

Hey buddy.

As 10x's linked to, the stock bolts are shouldered holding the pitch arm to the grip, Align also use these as frame screws on some models so the shoulder sits in the carbon frame.
.

[Gixxer]

Hey.

Unfortunately you could have multiple flights with the right ingredients to help a boom strike and not have one, then one day put the model/rotor rpm/blade pitch at just the right point and boom.
Anyway we're drifting off topic for no reason as it has no relevance here. Theres is a video on HF where a guy performs the same manoeuvre as Alex did and boom struck also, slow motion video tells the story.

With the bolts, bottom line have you had a failure here? If not then while the numbers are not ideal for proper screw to aluminium practice, in flight its not causing a problem.
As above be aware any screws added without a shoulder under the head could mean a weaker screw head, as the screw cut portion of the bolt now goes to the underside of the head, reducing the diameter of the bolt and it's strength.
Ideally a longer shouldered bolt is required, but this is immaterial if the thread it goes into isn't deep enough to tqke full advantge of the change.

With 2.5mm of thread engagement, the bolt breaking force will be twice that of the thread stripping force, so the shank on the bolt will make absolutely no difference to the strength of the joint, because the weakest part of the joint is the thread engagement, or lack thereof.

I don't know about anyone elses blade grips but mine took an 8mm bolt with no problems.

[Chris Boughton]

With 2.5mm of thread engagement, the bolt breaking force will be twice that of the thread stripping force, so the shank on the bolt will make absolutely no difference to the strength of the joint, because the weakest part of the joint is the thread engagement, or lack thereof.

I don't know about anyone elses blade grips but mine took an 8mm bolt with no problems.

I completely agree here!!! And yep I put 8mm bolts into mine no problem and not had any trouble since!! Id rather fit these for peace of mind to be honest!!