View Full Version : SAB 64cm blades on Logo 600
Wenlock
11-27-2007, 01:31 PM
The root of a SAB 64cm blade is so long that it's tight up against the capscrew in the end of the feathering spindle. As a result you can't fold the blade back because the corner of the blade root won't pass the capscrew. :arggg:
Someone must have come across this problem before with fitting SABs to Logos?
Unless someone advises me that it's a really bad idea, I'm going to mill the root of the blade to a round profile so it'll fit.
LITHIUMSTATIC
11-27-2007, 02:00 PM
I ran 620mm SAB on my old Raptor E-620 and you couldn't fold them back because of the same reason. Turned me off to buying anymore of their blades.
SAB 550 (#320) is what i use on the 500, a great blade, makes so much noise but is incredibly sharp. Really like them, and i can fold them back too :)
The root of a SAB 64cm blade is so long that it's tight up against the capscrew in the end of the feathering spindle. As a result you can't fold the blade back because the corner of the blade root won't pass the capscrew. :arggg:
Someone must have come across this problem before with fitting SABs to Logos?
Unless someone advises me that it's a really bad idea, I'm going to mill the root of the blade to a round profile so it'll fit.
Wow, thanks for the heads up, I'd just ordered some of these, I'll cancel that order now.
Let us know how they work out for you, I was very curious to see how they'd fly.
Flybar-less
11-27-2007, 04:10 PM
I'm going to try a set of the SAB 640s.
Wenlock
11-27-2007, 05:59 PM
I measured the gap between the end of the blade root and the capscrew, and it's just 0.4mm! The capscrew limits the movement of the blade to lead=20 deg, lag=10 deg. Plenty for flying I'm sure, but it just shows how tight things are!
I really like SAB blades, I run them on all my other helis. The 640 is a big solid blade, it really looks the business, so I'm quite disappointed to find they're not "plug-and-play" in the Logo blade grips. I wonder what the big idea is with having square blade roots anyway?
I find it quite difficult to get the blades into the grips because the grips are so tight, so I think it's essential to be able to fold the blades back over the tail - there's no way I'm removing and refitting the blades each time I go flying!
I'll have a shot at milling the "corners" off the roots and post the results as soon as I can.
jamesotron99
11-27-2007, 07:14 PM
chance you can post a photo of the blades in the grips?
Wenlock
12-01-2007, 12:21 PM
Pictures!
You can see the very small gap between the end of the blade root and the capscrew. I measured it with a feeler guage at 0.4mm.
(Yes, I know I only have one packing washer on, I still haven't figured out how to get both washers on together - those grips are too stiff. I'm sure someone posted the correct method to get the second washer in, but I can't find it.)
The "overhead" shots show how far the blade can swivel on the blade bolt before the capscrew stops it.
Hope that helps.
Wenlock
12-01-2007, 12:27 PM
This is a rough outline of the material that needs to be removed so that the blade can be folded back over the tail. It's only a couple of mm at most and it's on the thinnest part of the root, so I think it should be ok to trim it.
LITHIUMSTATIC
12-01-2007, 12:31 PM
I wouldn't do that if they were mine, not saying it won't work. My suggestion is to sell them and buy something else.
Wenlock
12-01-2007, 12:49 PM
What are the alternatives in the 640-650mm area? I don't know of any other blades between 620mm and 660mm.
jamesotron99
12-01-2007, 02:24 PM
Pictures!
You can see the very small gap between the end of the blade root and the capscrew. I measured it with a feeler guage at 0.4mm.
(Yes, I know I only have one packing washer on, I still haven't figured out how to get both washers on together - those grips are too stiff. I'm sure someone posted the correct method to get the second washer in, but I can't find it.)
The "overhead" shots show how far the blade can swivel on the blade bolt before the capscrew stops it.
Hope that helps.
Wow. That's really tight. You might be able to use some grips from another manufacturer?
LITHIUMSTATIC
12-01-2007, 03:09 PM
What are the alternatives in the 640-650mm area? I don't know of any other blades between 620mm and 660mm.
BBT Maniac 623mm are good. When I get a vstabi for my Logo 6003D I'm going to go to those blades or something near that size.
OICU812
12-01-2007, 05:28 PM
You can file those as per your picture, just be carefull, take your time and use a hand file to do it. The lay on a super thin layer of epoxy, use a 5 min expoxy. That will be perfectly fine, I had to do this to some BBT blades a couple years back in my beggining year.
Wenlock
12-01-2007, 05:49 PM
It's good to know that someone's been down this road before and lived to tell the tale! I think this is a fairly minor alteration, so I'm going to have a go.
Rather than use a file, I'm going to use a vertical milling machine with a rotary table and clamp the blade so it rotates about the bolt-hole (somehow). That should give a perfect circular profile. Good point about coating it in epoxy, I'll do that.
It probably seems a bit stubborn to persist with these blades, but I want to mount a camera on this heli so I need all the lifting area I can get. That's why I'm trying to resist the simple fix of going to 620s.
BBT Maniac 623mm are good. When I get a vstabi for my Logo 6003D I'm going to go to those blades or something near that size.
I actually preffered the 600mm v-blades to the 623mm maniacs Jeremy. And my setup is heavier than yours. 620mm v-blades would be the hotness.
Shawn and I were chatting the other day about the 610mm rotortechs, they should work very well with the v-bar due to their outward cg placement. I think he ordered a set to try !
I'll be trying 690mm rotortechs right quick here, providing this abnormally cold weather gives me a break.
Regards,
Nathan
Ticidytoc
12-02-2007, 04:15 AM
I have a set of RT 610 I wont be using, if anyone is interested. What are those SAB's? If they are 600's I might be interested in them if you dont want them. I'm good friends with Dr. Dremel he'll hook me up and make those work.
rscamp
12-02-2007, 09:29 AM
Even though the top portion of the cap screw does nothing for tensile strength, there is some risk in grinding the top of the cap screws down a bit to provide the clearance (for one thing, the material would have to be removed without generating too much heat changing the temperI).
I wonder if there is a button head socket cap screw that could be used? Nah. Probably too thin...
cptsnoopy
12-02-2007, 12:22 PM
Even though the top portion of the cap screw does nothing for tensile strength, there is some risk in grinding the top of the cap screws down a bit to provide the clearance (for one thing, the material would have to be removed without generating too much heat changing the temperI).
I wonder if there is a button head socket cap screw that could be used? Nah. Probably too thin...
??? different subject perhaps?
oops, thought you were talking about the blade bolts... Yea, I would not touch the blade-grip to feathering shaft bolts. You could be opening a can of worms with that thought.
Wenlock
12-02-2007, 12:58 PM
Even though the top portion of the cap screw does nothing for tensile strength, there is some risk in grinding the top of the cap screws down a bit to provide the clearance (for one thing, the material would have to be removed without generating too much heat changing the temperI).
I wonder if there is a button head socket cap screw that could be used? Nah. Probably too thin...
No way am I going to mess with the capscrew, there's too much chance of messing up the temper of the steel. And I'd only use a button-head screw if I could find one that I knew had at least the same tensile strength as the original capscrew.
Daniel Jetschin
12-05-2007, 10:42 AM
Maybe a thinner washer sitting on the spindle bolt will do it for you..
Flybar-less
12-05-2007, 05:00 PM
Daniel,
I have ordered a set of the 640s. How do you like them?
ozace
12-05-2007, 05:22 PM
So has anyone tried a set of the 640's in flight ? I have had a set for ages for another machine and i assumed they would be too heavy for hard flight.
Wenlock
12-09-2007, 12:17 PM
Maybe a thinner washer sitting on the spindle bolt will do it for you..
I don't think so, as the washer is only 1mm thick, and I need to gain more clearance than that.
Flybar-less
12-13-2007, 11:25 AM
Found some high grade torx cap screws for motor cycle brake rotors, in my shop, that will give the correct clearance with washers.