General SAB Main Blades grip issue

[totoheat]

Hello Guys


Am working on this new build on a Trex 550E PRO DFC Kit which is new one with 730MX motor and looking to have a more stable bird I get SAB 0330W 600 mm but and I found that they fit very lose on the 550 grips I mean they don't hold by grip the inside measure of grip is 12.04 when the blade has 11.76 mm am wondering if this is normal or this blades came defective as usually when I place the 520 mm blades and they are 11.84 mm on this same grips I have to push them in and bolt thigh with half a turn and there is no clearance between grip and blade

this make me think if there is no risk of breaking the grip as its made out aluminum and suppose not to bend and its not even tightness

this is first time I move to 600's blades


all comment welcome,thanks
Angel

 

[Dirk]

Hi Angel,

What blades are you using? The blades are normally furnished with some plastic washers that goes between the blade grip and the blade.

I don't think it is a good idea to induce any flex or bending on the blade grip by tightening the blade grip bolts like that. Metal fatigue is very real and the last thing that you want is for a blade grip to shear off. Very dangerous.

If you don't have any of the plastic washers, make some out of thin plastic.

 

[pvolcko]

Yeah, you need to get some washers to take up that space. Most of my helis have washers/spacers to fill in the gap between blade and holder grips. Usually they come with new blades with multiple sizes to account for the different fits.

 

[totoheat]

Doirk

They are SAB 0330W 600 mm for FBL 3D and I think same in regard to fatigue of the grips you know it would be quite difficult to fit any spacer there as clearances its only 0.01 mm but I can try with skin of plastic container so I can glue it to blade grip area I wont use them until I find way to correct this issue

I wonder if this is common in this blades or actually there is something wrong with this set of blades hope some one came out with any experience on this issue

I wonder if different maker as Align itself has same problem

Well thanks for your thoughts

Angel

 

[Lee]

Here is the Goblin manual.
Photo of a blade. Washers are needed. So I would try to find something to shim the gap.

 

[damhdearg]

Hey Angel, I have 2 trex 600's, both with the same dfc blade grips your 550 has. One has align 600mm blades and the other has edge se 603's.
One blade grip measures 12.03mm and has the align blades which measures 11.98 mm thick, no spacers.
The other grips measures 11.99 and has edge blades which measure 11.92 mm thick, no spacers.
The logo 600 I have also runs edge 603 but needs 2 of the spacers that came with the blades.
All my blades are tight enough that it takes a good amount of effort to pull them back into the blade caddy. The blade bolts dont show more than 1 thread beyond the locking nut on any of them.

 

[totoheat]

Lee

Thanks for that, am looking for plastic piece to fit in gap what I would do will be glue it in blade grip area so it wont move when blades fold for transport


is good to know that it wasn't good idea tight bolts with that gap

Angel

 

[murankar]

You should not need to glue anything. The bolts should hold it in place.

Sent from my LG-E980 using Forum Runner

 

[totoheat]

Is rare that this SAB blades also have a different size in gripe area one of them measure 11.75 and the other is 11.86 so maybe they are defective I check what Lee comment and what I need to find its a piece of plastic of 0.02 mm thk I think it would be better to grind it wit sand paper to reach that size

But I still wonder SAB its a very good quality blades how came they fit lose in grip and has different size each of the other besides this blades did not came with any spacer at all


Angel

 

[murankar]

It is possible for a bad set of blades to come to market. Normally that small amount of difference wouldn't phase me, bit in your case the thinner root blade is on the way to thin size.

I would call, email or chat with the distributor about the blades and see if they will replace them.

This can happen with any manufacturer no matter who they are.

Sent from my LG-E980 using Forum Runner

 

[pvolcko]

Do not use plastic. This is a crazy high stress/fatigue point. Plastic will likely fail in short order. It needs to be a metal (aluminum usually) spacer/washer. Most of mine I only use one spacer on the top with none on the bottom. On the SAB Goblins with SAB blades the kit usually has spacers properly sized to fit one top and bottom per blade, which I do on them.

 

[totoheat]

Paul

Thanks for that, I can make a spacer from aluminum mean washer but in this way the grip its only going to have contact with blade 16 mm diameter is this enough area to avoid vibration or having blade going lose? I wondering if I made a piece of aluminum with same shape as the blade grip area so grip can grab blade in all its length the only problem is that am not going to be able to fold the blade for transport as easy as if you use a washer that's is round

I have seen that in most of blades kits they came with washer spacer,well is just an idea but it may be enough with washer

Thanks for your advice,i will come back with a photo of grip/blade fixed soon


Angel