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Logo 600 › Sheared the Logo 600 3D Main Shaft IN FLIGHT (Not a problem in general but a freak incident)
02-04-2008 11:15 PM  10 years agoPost 1
Eco8gator

rrElite Veteran

Palm Beach, FL

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Hello

We fly the Logo extreamly hard and I'll fully admit that. We have absolutly no mercy on it but were only flying as hard ad Daniel does. We have to do this to test the ProBar.

So far we have compleatly destroyed a one way hub.

And now, we literally sheared a main shaft in flight!

I wish this was on video because it was the most insaine thing Ive ever heard of happening. The head literally floated down pretty soft.

Upon inspection we found that the shaft broke at the collar. The shaft looks pretty thin IMHO.

Is it safe to say that there really is a mechanical limit to what you can do with this machine because its defintally not holding up to the level of pounding Chris is capable of and now it's going to cost us hundreds to get it back up. This is a 3D machine and IMHO we are flying it to spec.

Should there be a side note to replace the shaft after X hours of flying even though its not tweaked at all.

I am very dissapointed now, but happy that our proto board isnt damaged(goes to show you that electronics can take a beating). Im not happy that one of our 8717's are tweaked and the over all damaged caused to the frame by the shaft letting go.

C
PS: Id just like to note that for most people the Logo is fine but at the level that Chris flys It may not be enough.

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02-05-2008 12:05 AM  10 years agoPost 2
Ticidytoc

rrApprentice

Los Angeles, Ca.

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I'm going to venture to say you didn't have the hardened shaft on it?

I told you it was the future........

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02-05-2008 12:41 AM  10 years agoPost 3
Eco8gator

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Palm Beach, FL

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Yes its hardened.

Id just like to note that Im not expecting someone to help me out on this but I hope some of what we said is taken into consideration.

Chris and I arnt sponsored so we pay for everything out of pocket and when stuff like this takes us down its really hard to swallow.

So you know what we lost today:

5s Flight Power Pack
CCHV85 ESC
Radix Blades
8717 servo
Boom
Main Shaft
Canopy

...yeah $$$

Thats not all of it but as you can see this is not cool.

C

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02-05-2008 03:49 AM  10 years agoPost 4
kogibankole

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albuquerque/ibadan

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did you tighten the collar down too hard? what hs were you running?

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02-05-2008 03:57 AM  10 years agoPost 5
Eco8gator

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Palm Beach, FL

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We tightened the collar down tight. We dont want it slipping on the shaft with how hard Chris is flying.

The HS is governed to 2k for the high HS mode and lower for the other flight modes. This is reasonable IMHO.

C

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02-05-2008 05:22 AM  10 years agoPost 6
cptsnoopy

rrApprentice

Phoenix, AZ USA

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This may seem a little backwards but if they make a normal (not hardened) main shaft maybe you would be better off. I really don't know because you will eventually fatigue it too. Just a matter of which will last longer with the tremendous strain Chris will put on it.

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02-05-2008 06:47 AM  10 years agoPost 7
OICU812

rrMaster

Edson, Alberta, Canada

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No offense to Chris as he is a spectacular pilot, however I hardly think he flies harder than Danny does and I know for certain he or any of the other German gang have not seen this. I did have a shaft break on a crash, but never a bend or break in flight that is for sure. Very bizzare and unfourtenate for sure. Send it to Ralph for certain I would think. They could evaluate the shaft itself and the metal quality etc.

...Once upon a time there were Nitros, flybars and frequency pins...

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02-05-2008 08:54 AM  10 years agoPost 8
Mercuriell

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Sunshine Coast, Queensland, Australia

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The shaft is hardened and reasonably brittle - if if flexes against a fixed point like the collar or the rotor head it will work harden and become more brittle and break rather than bend under load - as Shawn says - very unfortunate and chances of repeating very slim - I've just put on the ordinary steel shaft and it looks quite good - less likely to work harden maybe.

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02-05-2008 01:20 PM  10 years agoPost 9
Eco8gator

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Palm Beach, FL

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Not saying Chris flys harder than Danny but Im pretty sure they are closer in ability than most pilots in general. We will have to see how close in competiton but thats another story

But yes this is unfortunate and I hope to get this bird back up sometime soon.

Im defintally willing to have this shaft sent to mikado for analysis to figure out what happened.

Curious would a solid hardened steel main have lasted longer?

C

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02-05-2008 01:26 PM  10 years agoPost 10
Eco8gator

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Palm Beach, FL

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Ralf just got back to me and we are working this out.

C

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02-05-2008 02:09 PM  10 years agoPost 11
rerazor

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Mich.

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Wow!!

Ralf will take care of you.

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02-05-2008 03:23 PM  10 years agoPost 12
ChrisT88

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FL

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Hi Sean,

It does seem DJ has broken a shaft mid-flight. Here misskimo mentions it:

http://www.rcgroups.com/forums/show...96&postcount=18

And to be honest I'm surprised anyone knows of even that issue as it's not common practice for a company/reps to advertise faults of any product or design. I doubt DJ or Mikado make it a point to let anyone know which is why we felt the need to post on the issue.

That said, I have been asking myself recently "what could actually go wrong?" And I continued to push. This in itself says a lot but I do believe the shaft is just a tad bit too thin or hard.

My personal biggest gripe about this machine is the frames that left one of my two 5s packs hanging out the front to be destroyed. How did Mikado make the mistake of leaving packs hanging out of the heli unsupported and exposed...AGAIN.

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02-05-2008 03:32 PM  10 years agoPost 13
kogibankole

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albuquerque/ibadan

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im actually surprised that the shaft broke above the collar...i would have expected that the force against the upper frame bearing would cause it to break below the collar..

if anything would break that main shaft I suspect it would be the way DJ flies his 600. IMO I think its just a freak accident. I don't suspect we will see this often. I remember when you mentioned Chris snapping a set of blades on his/or your knee after a flight. This seems ridiculous. How would he have known that the blade was going to break? These are some things that I dont understand.

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02-05-2008 03:39 PM  10 years agoPost 14
ChrisT88

rrVeteran

FL

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im actually surprised that the shaft broke above the collar...i would have expected that the force against the upper frame bearing would cause it to break below the collar..

if anything would break that main shaft I suspect it would be the way DJ flies his 600. IMO I think its just a freak accident. I don't suspect we will see this often. I remember when you mentioned Chris snapping a set of blades on his/or your knee after a flight. This seems ridiculous. How would he have known that the blade was going to break? These are some things that I dont understand.
I can see being surprised about the blades from someone elses point of view but the shaft collar makes perfect sense. The head is moving the airframe so the leverage of the shaft is all focused around the bearing/collar, but I think you missed the fact that the collar is helping transfer the load onto the main bearing. This is why it snapped above not below.

FYI, the Thunder Tiger 600mm blades we broke had what looked like a crease around the CG point and Carlo lightly flexed them to verify and snap (most pilots check blades rigidity spawn-wise and chord-wise twist). We had tracking and vibration issues randomly startup a few flights before that.

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02-05-2008 03:42 PM  10 years agoPost 15
Eco8gator

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Palm Beach, FL

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How could I have known.

Fluttering was the the big sign and it was a set of very cheap TT 600 blades with the weave in the incorrect orientation(90 deg to the leading edge instead of 45).

We couldnt figure out what was causing it and I was curious about the blade flex. From there the blades gave very easily...we got lucky.

Ive seen Jarad from TT shear a spindle in flight and have read report of other freak things happeing...but only to the Pros. They do things that we cant and they push it to the extream or they wont win.

Dont wonder why just know that it happened and your looking at it in our pictures.

Keep in mind this machine could have been in an event and have blown up at the flight line. Not good at all when pilots are expected to push it to the limit during demos.

C

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02-05-2008 03:52 PM  10 years agoPost 16
kogibankole

rrKey Veteran

albuquerque/ibadan

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okay so the blade was damaged before the flight? The way I read it, it seemed as if the punishment you put on the heli through the system you guys were working on/testing caused the blade to actually get weaker and break.

The collar serves the function of trapping the main shaft. This is an up down motion. I agree that there will be tensile stress on the shaft due to the force of the heli accelerating. I highly doubt that this is enough to snap the shaft. It would have had to neck first (elongate)

On the other hand, the cyclic forces from the main blades are transferred through the shaft to the body of the helicopter. The point at which the shaft meets the heli is just above the upper bearing. This is why I find it very weird that the shaft would break above the collar. Anyways it did break above the collar and I feel a proper analysis is required.

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02-05-2008 04:23 PM  10 years agoPost 17
Eco8gator

rrElite Veteran

Palm Beach, FL

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The blades worked fine initally. There is a good chance that flying them hard could have stressed them to the point they were about to break...but at least there was a sign that they were going to let go.

I got PM's from some other well know pilots give me reports that our blade situation has happened to them as well. Ill let them chime in if they want to.

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02-05-2008 05:33 PM  10 years agoPost 18
T-rexn8

rrKey Veteran

CoLoRaDo

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Keep in mind this machine could have been in an event and have blown up at the flight line. Not good at all when pilots are expected to push it to the limit during demos.
Too true. Earn yourself a bad rep. for something not your fault.

I hope that everyone here has actually seen Chris fly before they comment. He is pushing the machine harder than any of us posting here Im sure. Those piro tic tocs are SICK!

Hope you guys get this sorted out and regain some confidence in the machine.

Xxtreme 800, TDR, 700E DFC, Mini Protos, T-450 DFC, Blade 130x, mcpx, nano

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02-05-2008 05:39 PM  10 years agoPost 19
Dr Lodge

rrElite Veteran

Guildford, Surrey - UK

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Main shaft fracture
Out of interest, what temperature were you guys flying in?

Vibe 90, Vibe 50, Vigor CS x2,
Dyna-x, Knight 503D, Logo 10,
TRex 500, Furion, Gaui EP200

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02-05-2008 06:10 PM  10 years agoPost 20
Eco8gator

rrElite Veteran

Palm Beach, FL

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Hello All

We typically fly in warm to hot humid weather. About 70-100 degrees F.

C

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Logo 600 › Sheared the Logo 600 3D Main Shaft IN FLIGHT (Not a problem in general but a freak incident)
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