Torque on the four rotor blade bolts?

[Vance]

I am hopeful someone can tell me how much torque should be on the four 3/8 fasteners on the Sport Copter 8.5 inch chord rotor blades.

It has been several years since I had them off and I just don’t remember.

Thank you, Vance

[mark treidel]

Vance,
According to the chart, 95-110 in/lbs. for 3/8" A/N bolts...A/N 6's.
I'm not familiar with the proper set up that Sport Copter advises so prudence would indicate a quick call to them but I'm certain you've already done that.....hope this helps a bit....
at least it's in the ballpark.

[Master Roda]

Vance,
The assembly page for your size suggests 20 ft/lbs. Call the office and request a new torque sheet and tracking tabs. I will ship them out when I get the order from the office (NO CHARGE).

Jon

[Vance]

Thank you Mark,

My book known as Advisory Circular 43.13-1B with Change 1 read 160 to 190 inch pounds with a maximum torque of 390 inch pounds. Jon’s recommendation of 20 foot pounds AKA 240 inch pounds is well within that range. This sort of divergence is exactly my reason for asking.

I have found that when working with unusual structures that the standard torque range, 160-190 inch pounds, is not what is used. The castellated nut being lined up with the hole precludes a specific torque although different thickness AN washers make it possible to get close.


Thank you Jon,

I called the Sport Copter office and they don’t open until 8:00.

I will call back later and order the sheets and tracking tabs, my tabs are a little tired.

I found the marks on the aluminum plates confusing. I have an A and a B blade and an A and B end of the hub bar. Do the aluminum plates marked A and B stay with the A and B sides of the hub bar or is A on the top and B on the bottom? I may have assembled them incorectly previously so going by the fading on the plates my not be best practice.

Thank you, Vance

[Master Roda]

Vance,
The plates are ambidextrous, although their orientation is particular, it is not detrimental to their function. If you hold one over the blade and align the holes, the plate should not hang over the pad on the blade itself. The bottom plate should mirror it.
If that's confusing, I'll send you a picture.
Jon

[Vance]

Thank you John,

I feel I may understand.

Why are the plates marked A or B?

No need for a drawing. If I understood you correctly I am not likely to be able to screw it up.

Thank you, Vance

[Master Roda]

Vance,
I use to mark them for weight. I simply just don't anymore because they all weigh within a couple of grams of each other. No need to add unnecessary steps.
Jon