The aborted takeoff......& broken prop

[Dennis Garrett]

Beautiful, crisp, cool, fall morning, hooked the trailer up & headed out to the field. Unloaded the PC-2000, warmed it up, drove out to the spot I picked to take off from. I laid out the chute, shook out all the lines till it looked right, rolled the leading edge under so it wouldn't catch any wind from the prop during the final warm up. After a minute or two, I hit the throttle to roll ahead & pop the chute up & begin my take off roll. As I looked up to watch the chute, I could see from the start that it wasn't kiting like it should, and all of a sudden instead of going horizontal, only one side wanted to fly, and the other side dived toward the ground. I could see this wasn't going to work, so hit both mags to kill the engine, just as the chute was jerking the cart around about 90 degrees to the take off roll. I heard something pop right then, but with my ear protection on I couldn't hear much, & didn't give it another thought. I got the cart straigtened up into the wind again, laid out the chute, set it up for another attempt. As soon as everything was ready I gave it full throttle, but at about 5800 RPM, I heard the engine "missing", and I couldn't get full power. So I killed the mags again, & decided something was wrong, & I better not leave the ground until I figured it out. Everything looked OK during the pre-flight inspection, so I decided to take all the spark plugs out & see if anything was carboned up or fouled. No, they all looked fine, so I got down in the grass, & took the fuel filter out & changed it. Still no power, only 5800, should see 6350 or so. Also had an odd, "missing" sound above 5000 or so. Well, after a few minutes of looking , I noticed a smudge mark on a verticle engine support tube that shouldn't be there. As I looked further, I found the problem. One of my prop blades had broke across the back side, but was still intact, & looked normal at first glance. At high RPM, it was not catching air like it should, and was dragging the engine down to 5800. It was also damaged on the tip where it hit the tube, and that broke it in half on the back side about a foot from the tip. It must have happened when I heard the pop sound, when I was aborting my first take off attempt. It had to have flexed the frame & rubber engine mounts enough to allow the blade to hit the support tube. Anyway, glad I didn't go ahead & get airborne, I could have done it at 5800, and I was tempted to try it, thinking whatever it was it might smooth out in the air. The prop would have dissintegrated, and the other to blades would have put the whole thing out of balance so bad it might have ruined the engine or mounts. Took it apart, & got another blade ordered. (PowerFin, Bear Perkins $120) Will have to put it back together, pitch it, & hope it doesn't happen again! ..............(29 hrs & counting)

[ZipItyDoDa]

Only had this happen once.
I was setup to go and heard something....a line had somehow got caught by the prop and blew one of the blades. Inspected the lines and saw a flat spot, with no cut in it at all. And the flat spot came right out of it.
But the one blade was a mess. I have a spare set, so just changed them and sent the two in to get matched to a third again. (IVO blades)

So yours may have been a line too and not flexing enough t reach the tubeing.


Ed

[bknorr]

Dennis, thanks for sharing your experience, and sympathy for having to replace a blade. I don't know about others, but I have experienced exactly the same thing you did, except that I hit the brake just before I cut the mags, (confused) dropping the chute into the spinning prop. Cost a little more than a blade would have. Every time that I have thought I had kiting the chute all figured out, something has happened to prove me wrong. I have come to the conclusion that there is no perfect lauching technique that works 100% of the time. Some are better than others, but none are perfect. Most of us will have to deal with an incomplete initial chute inflation occasionally, and the key is to detect it's presence early enough so that we can correct it before it gets us out of shape. This means to me that I must stay in touch with what my chute is doing from the instant it begins to inflate. Some do it by turning in the seat to watch it directly, some use a mirror, some do both. I haven't found the perfect way yet, but at least I think I am now pointed in the right direction. Good luck to you. Bill

[Joe LINY]

Ed, in your incident, did you have much power on at the time? 2 weeks ago I did a warmup, with the chute bagged and strapped along one side. Well this particular time the right side lines (still in the sock) got sucked in the prop- I heard 'whap whap' as I shut down, but no cuts in the line or line sock. I too had flat spots in the lines, I just got the chute back from inspection at PD, no problems.

Anyway, the leading edge tape got abraded on all three blades (Powerfin), I'm waiting for new tape to arrive. When you say you 'blew the blade' -was it just nicked hard, or actually break? Just curious, and would like to know what to look for when I pull the old tape off...

Thanks

Joe

[ZipItyDoDa]

I was just idling warming the engine back up. I have never had something like that happen except for that one time. I have the holders for the lines on the prop ring, so I'm guessing a gust or vortex from the prop moved a line enough to get it.

It was a tad worse than a nick I'm afraid...I have it hanging on the garage wall as a reminder....just ONE string.
(Hard to believe!!!) :eek: :eek:

[Hiflyer]

I've caught lines in the prop 3 times. Lost all three blades each time (powerfin). They just peel open like a banana. I just switched to WarpDrive. I don't know if I have solved the line wrap problem but at least it won't cost me a new prop each time.

[Joe LINY]

Man that's painful! Both Ed's and Hiflyer's incidents make me cringe. I think I'm gonna hunt down a can of crack detector and eyeball my prop a little harder...