LOL.... This morning I woke up and decided "I WILL AUTO TODAY" Yea, not so much.. worse part is my Auto wasn't all that bad, but an "Upgrade" I did prior to arriving at the field, wasn't one of my smarter ideas..
I wanted to add a stinger to the vertical tail to help keep the tail rotor out of the dirt. So I split a piece of aluminum tube in half, half way down its length, slid this onto the vertical tail, and put a bend at the end. When sitting flat on the skids, my new stinger was an inch or two above ground. I was pretty proud of it, but clearly I didn't think my plan all the way thru..
The problem happened when I did a kinda hard landing, while attempting my first intentional higher altitude auto. If I had left things well enough alone, I'd probably still be at the field flying. What happened is the stinger worked like a spring and bounced the tail boom up into the rotor disk.
Here's what It looked like from my point of view...
On board HI-Def video is being uploaded now. Not as interesting as I thought, but still.
Wouldn't have been so expensive if I hadn't taken out one of the main rotor blades. Do we have a swap meet somewhere to trade all our lonely non damaged main blades.
James Lerch - ManateeRC Member - Blade 400 - Raptor 60 - Lots of sim time
To me it looks like you burned up your blade speed at the 4-6' mark and had nothing left when you set skids...
As always, it's my opinion only, but maybe I missed the "spring" action your describing. Just too aggressive on the flare and nose attitude of the bird.
Pull-n-Pitch
05-11-2008 03:46 AM
Jlerch Heliman Location: Parrish, Florida
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Was it the right or left rotor blade that was damaged ??
Definitely the left blade.... The right blade is just fine.. Do you have a spare MAH G2 690mm 14/59-49 Left blade?
But seriously, does anyone have a MAH G2 690 blade they want to get rid of?
James Lerch - ManateeRC Member - Blade 400 - Raptor 60 - Lots of sim time
To me it looks like you burned up your blade speed at the 4-6' mark and had nothing left when you set skids...
Very Possible, but I don't believe I had that high of a sink rate when the skids made contact.. (I'm also a clueless newbie :-) )
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As always, it's my opinion only, but maybe I missed the "spring" action your describing. Just too aggressive on the flare and nose attitude of the bird.
Watch the video again, but this time pay attention to the 2nd "mini" low altitude auto I did. Specifically, watch the tail "bounce" in an odd manner.
Better yet, here's a video loop of the bounce in question.
Alternatively, is a boom strike the expected outcome of a low head speed, high sink rate, failed auto rotation landing?
James Lerch - ManateeRC Member - Blade 400 - Raptor 60 - Lots of sim time
you might also consider learning autos onto asphalt or concrete, especially if you're going to do them in forward flight - that way, it will "skip" across the ground instead of sticking to the grass (speaking from experience, of course, as in, I've crashed EXACTLY like that before)
05-11-2008 04:49 AM
Mark C Key Veteran Location: Houston, TX - USA
Here's what went wrong.
1. You violated the #1 rule of autos. You hit the back of the skids. Never hit the back of the skids, never hit the back of the skids, never hit the back of the skids, never hit the back of the skids. Burn that into your head. When you hit the back of the skids it kicks the boom up into the blades. In your case your "stinger" contributed to this.
2. Your blades were too loose. When your blades are too loose it s easier to boom strike as your boom springs upward at low headspeed. As your boom springs upward at low headspeed your blade wants to continue on its current path of arc and to do so it breaks forward (or backwards depending on the situation) in the blade grip and continues on its path of arc right into the upcoming boom.
If you still have forward speed that you couldn't bleed off then hit the skids flat and slide.
Good luck next time, Mark C.
05-11-2008 04:54 AM
freakyreef Veteran Location: usa
I have been watching the vid again. Maybe my eyes are just bad, but the skids looked pretty level AT touchdown. Is it just me or an optical illusion?
Evo 50 Hyper, 9CHPS, 9252, gy-401\9254,CSM RL-10
05-11-2008 05:05 AM
Mark C Key Veteran Location: Houston, TX - USA
Every time I watch it I see the back hit first and the a$$ spring right up and into the blades. It does look like his "stinger" added to the equation .
Edit: you can even see the blade break loose in the blade grip. I even think you can see the boom flex as the back of the skids and the stinger hit.
05-11-2008 05:12 AM
GyroFreak Key Veteran Location: Florida ... 28° 50' N 81° 16' W
Gotta hand it to you man, no screaming, no cussing, no kicking and stomping, no blaming it on the heli. You kept your cool (at lest on the video audio) and simply evaluated what went wrong. Thanks for posting, I learned quit bit from this and the follow up postings. Did you have your video camera mounted on your hat or what ? Since I fly alone often when learning something new (keeps from killing other pilots) I'd like to take some videos of my crashes to see what went wrong.
Support bacteria. They're the only culture some people have. !
05-11-2008 05:24 AM
QuickSilver Veteran Location: Cherry Hill, New Jersey
JMOIm not sure why you put that thing on the tail in the first place, because the tail fin itself is long enough to keep your tail blades off the ground
Life is not measured by the number of breaths we take, but by the moments that take our breath away.
Is it just me or an optical illusion. At 1:30 in the video It looks likes the main blades start to move in the opposite direction.
Common sense is not that common
05-11-2008 05:50 AM
helibandit Senior Heliman Location: Jacksonville, North Carolina - United States
that should buff right out..
The only time you can have too much fuel is when your on fire
05-11-2008 06:12 AM
Jlerch Heliman Location: Parrish, Florida
I put the stinger on because the last time I made an aggressive landing (read: I noticed that the header tank was nearly empty!) the skinny little tail fin just sliced into the dirt and I took out the rear rotor gear set. I'd heard this was common with the stock vertical fin, so I thought I'd find a cure for that problem.. If only I had known :-)
Mark_C, How'd you know my blades were loose :-) I know that knowing how tight a blade should be is difficult advice to dispense in writing, but I thought they were ok, but now I'm not so certain..
BTW, your description of the blade breaking free and rotating in the grip makes things so much more clear. I've been trying all night to figure out how the main shaft, feathering shaft, dampeners, or blades warped enough for the leading edge of the main blade to make near perfect contact with the boom support allen bolt...
GyroFreak, To be honest, the word "DAMMIT" did slip between my teeth as my brain took in what happened.. :-) I use my "Hat Cam" to record all my flights (and crashes). Basicly its just a point and shoot digital camera (Pentax Optio W20) that I screwed and zip tied to the bill of my baseball hat. Nothing fancy..
BTW, here is the whole flight recorded in high definition from the point of view of the heli. I didn't edit it as its a pain in the arse to re-render.
I did edit up this section with just the Autos and the crash from the HD-Camera, Not really much there, but I was a touch nose high when all hell broke loose..
Noodle alternativeJlerch, That was wild! Sorry that happened. If you want more clearance on the tail blade try using a foamy apparatus on your skids AKA a ‘noodle’. It will give you an additional inch or so. Unfortunately, I fly in an open field that is uneven and rock infested so I had to overcome and adapt as well. I found that this trick also helps cushion the landing and my orientation when I’m up against the clouds. I’m blind so I need colors that screams. Check out my gallery for visual.
Trex600N Pro Kinetic 50
-The ONLY way you fail is when you quit.-
05-11-2008 07:38 AM
SkyWarp Heliman Location: Planet Earth
Wholy rusted mellow Batman!!! It looked like your heli tried to Transform. Ouch! Can't say I've seen that before.
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Noodle alternative
Zman, I've seen aerial photography pilots using that technique. Good idea!
Century Swift- When in doubt, pull out. And that applies to everything.
05-11-2008 08:05 AM
Mavrik1 Senior Heliman Location: Tucson, Arizona
Jlerch,
Would it be possible for you to post a close up picture of your hat cam?
