Skywheel Blades...are They Safe? back to topic

[Phil_Ruffin]

Posted by Gyro (Paul)
I recently purchased a set of 23' McCutchen Skywheels rotor blades. they appeare to be in good shape but I think they are an earlier model....most likley when they were first produced. I have a later model hub that I was going to stick them in and the bolt patten does not line up. the hole closest to the center does but the 2,3,4 holes are out. The hub that it came with is fine but it weighs nearly 3lbs more and is a little thinker.

I had a set of 23's and messed one up and got another set of 25' to replace them. I had the same problem you are having. Here's how we (Scott E. and myself) fixed it.

Put the blades in the hub and put in any bolts that will fit.
String the blades as best you can get them.
Take a centering bit and drill new holes in the hub to match the holes in the rotor.
Take a doughnut type bushing and recess it flush into the new hub holes with epoxy.
Bolt the blades together and hang them by the Jesus Bolt
Use a water level and add weight to the higher blade until it matches the other blade. (this can take some time to get right because of the bobbing of the blades and there can be no breezes in the shop)
You may need to adjust the tracking once back on your gyro

Hope that made sense.....

These blades flew just fine, here is a photo of my old hub bar.

 

[Phil_Ruffin]

Here's a drawing of the type bushing we used.

 

[gyro]

Looks good Phil, I like what you done, clean and neat! Did you buy the bushings or make them? did you do the drilling by hand or set it up in a drill press or mill?

 

[Phil_Ruffin]

Scott had the bushings already and I drilled the hub by hand. It wasn't hard to do, just take your time.
What took the most time was balancing the blades, I ended up with a piece of tape wraped around the end of one blade to make it balance out even.

 

[MOL]

Thank you for the advice Dennis and Phil.
I too had the idea of these types of bushings. I had it from the workshop where we repair honeycomb floor panels to the Boeing 767 as similar bushings are used.
Though, the holes in the blade Aluminium bar are also a little too large, so I will still have a little play there.
I will get metric bolts, as they are standard here in Europe. I can even get them as "close fit".
I will use this bushing idea also, because I don't want that hole in the fibre to enlargen itself again.

 

[scottessex]

Yes MOL they were 767 floor panel bushings. good eye.
We used a spot face bit (or counterbore) with a pilot. centered off the actual hole in the rotor blade, then the spot face cut the fiberglass on the hub bar perfectly centered over the hole in the blade. Epoxied the bushings in to reduce the hole size back down, and now perfectly centered. All this time with the string on the blades to make sure that they were staying in correct alignment.

Here is the type of bit, and a pic of the pilot.