RAF New Blade Report

Date: October 21, 2002 11:57 AM
Author: Albert Huizinga (albert@ee.ualberta.ca)
Subject: New RAF Blades

I was at the RAF factory a few weeks back. I saw the new molds. Apparently fewer steps are required to make the new blades, they are very consistent, and require less manpower to build. I was on the ground when a pair was being tested. They sound different. There is less wop wop in a tight banked turn, and they seemed quieter in level flight. A person with me made the same observation. The blades were tested on two different gyros. Both pilots told me the blades were smoother.

So yes, RAF is making new blades. This is what I saw. I don't work for RAF.
Albert Huizinga Edmonton Alberta Canada

Date: February 01, 2003 06:35 PM
Author: Scott Larsen (slarsen@evansville.net)
Subject: Flight test #1

The overcast finally rose sufficiently to permit a flight late this afternoon. Winds a fairly steady 8-9 mph, very little turbulence. Told the tower guy this was the first flight on new blades, so I might be putting it down on the end of the runway. He thanked me for the advance notice.

Observations:
RPM's were right where I want them: about 312-315 RPM's alone. Stick shake was about what I was getting after numerous adjustments with my old blades. Well, maybe a slightly larger orbit, but not much. Intensity about the same. Cabin hop was worse than I have experienced in awhile. The sensation was less of a steady vibration and more of a sort of "lope" or "hop". Blade tracking needs adjustment. I had put red and white reflective tape on the blade ends (several posts on this subject this past summer) and had my 1.5 million candlepower spotlight with me, so I already know which way to adjust the blades. Track error is at least two inches, maybe slightly more.

Somebody walked off with the ladder that used to be in the hangar (not mine, so I can't complain too loud) so I'll be taking mine over there, maybe tomorrow. I'm planning an initial adjustment of a combined .080 split between the two blades, in the hopes that should bring things close on the first adjustment. Does anyone have any advice if that is the right amount for a 2" adjustment? I can't recall specifically what a 1" adjustment is, can't find it in my notes, and can't find any reference in the manual, just that a .040 adjustment is "normal" whatever that means.

Scott Larsen - Newburgh, Indiana

Date: February 02, 2003 07:37 PM
Author: Scott Larsen (slarsen@evansville.net)
Subject: flight test #2

I adjusted the high blade down .040 and the low one up .035. Flew them. The gap is down to about 1/2 inch now, from what I would say was a bit more than 2". The results were dramatic. Stick shake decreased to about 1/4 inch oscillation, actually more of a straight forward and back shake rather than much of an orbit. This was a substantial improvement, and better than anything I ever experienced with my old blades. The cabin hop was much better, too.

I have a wire that powers my electronic compass (mounted to the windshield) that spans from the dash mounting screws at the top of the dash. I would guess that the longest span is about seven inches; the screw from the center to the next one down and to the right. Then it is attached to the next screw further down and to the right, and from there, down to a cigarette lighter-type recepticle at the lower right on my dash. The wire is coiled, about like as if it had been wrapped around a pencil, and the wire is not pulled at all tight. Sort of like a telephone handset wire coil, only smaller. Just from its own weight it hangs down about 1/4" or so. Anyway, the wire vibration, I note, was minimal. Nothing like before, where it vibrated like a tuning fork. Maybe a 1/8" oscillation.

I am very pleased with these blades. I think I can get it just a bit better, based upon the remaining 1/2" mis-tracking, but even if I can't, its a substantial improvement. I'm trying to sneak up on "perfect" tracking, because last summer I overshot the target, still had some runout to remove, continued to adjust in the same direction, made things much worse, blah, blah. Took more than a half-dozen iterations. I'm hoping to get it with only a couple more adjustments. Then I think I'm done. I don't see any reason to fool with the chord screw at the moment.

BTW, I replaced the teeter bearings while I was down for three weeks. A local industrial supplier had them in stock. Just under $5 each. I cleaned up the inner race with some very fine emery cloth; it looked more like staining than wear. I'm thinking that it might be good to occasionally loosen the rotor mounting bolt and rotate the inner race a quarter-turn so as to spread out the wear.

Scott Larsen - Newburgh, IN

Date: February 05, 2003 06:32 PM
Author: Scott Larsen (slarsen@evansville.net)
Subject: flight test #3

Test flight #3, following a small (.010) adjustment. Very good day; sunny with a very slight haze, light and variable winds, cool: mid-30's, but pleasant given all of the rest. Ran the heater half the time.

Out of track is still present, but getting difficult to analyze as it gets smaller. I can no longer tell for certain which blade is higher with the spotlight, at least not in daylight. Maybe I'd do better if it was getting dark. I'm still trying to sneak up on perfect tracking, made a .008 adjustment before I left the airport following this flight. And the result of the prior adjustment was:

I've never flown in a gyro this smooth. Not that I have a huge amount of experience, but I've flown in four RAF's and one Twinstarr. I didn't have a camera with me, but I pretended I did. I held my hand up and pretended to take a picture out of the left window over my shoulder with my right hand, and out the front. Watched my unbraced, open fingers for movement. Held my finger out in front of me, horizontally on the horizon, trying to picture what at would be like to have a video camera in my hand and how much the picture would bounce around.

Its a whole different situation. I would not have seriously considered videoing before, but I don't see a problem now. I note that on the way home, on a smooth and fairly new four-lane road, my finger bounced around on the horizon more in my Lexus than it did in the gyro. And I would never have hesitated to video from my car.

I feel like I've finally got the gyro I always wanted and constantly pursued, with bad results at least until this past fall, for four years. (I had gotten it tolerable, but not even close to what I am experiencing now.) I am seeing things I could never pick out before, like the way the stick shakes when the rotor disk is disrupted (additional shake) by a small change in air currents, then slowly returns to the way it was. I find it easier (less gut-wrenching) to let go of the stick for a couple seconds to pick up the spotlight, reach for the radio, pick something up from the floor, whatever. It even seems like the average engine speed is down about 100 RPM's or so, but I don't know why that would be.

I would compare the new feeling of relaxation and sense of security to be on a par with what I felt when I added a horizontal stab. I'm not comparing the stab to smooth blades in terms of safety as such; just that getting the cabin hop and stick shake to such a minimal level is a huge load off my mind, and just feels so much better. Less tiring, too.

I would recommend the new blades. I can only assume (and hope) that others would have the same experience as I have had. It is so nice not to be rattled about, and I am looking forward to taking up others and getting their impressions.

Scott Larsen - Newburgh, IN