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Synergy R/C Synergy N9 > Mid-Air Boomstrike
 
 
carzan
Veteran
Location: The Lone Star State

Dylan had a Mid-air boomstrike today. It was Bad! Cut the entire tail off while he was vertical then started the FASTEST pirouette I've ever seen. His blades were extremely tight so I don't think a blade folded besides, the blade that looks like it struck was still straight out and I couldn't move it in the grip! So what can be the causes of a mid-air boom strike. I would like to know if there is anything on the heli I can look for.



Thanks in advance.

Jay
05-19-2008 01:33 AM
HOMEPAGE  
 
 
Futura SE
Veteran
Location: Fayetteville, Arkansas

Jay,
Throughtout the years of flying I have seen several things cause them. 9 out of 10 times it is too soft of dampening. I am going to assume you had the dampening set hard. Basically without seeing a video of how he entered the move there is no way to tell. You can boom strike anything if you enter the move too hard or too abruptly. Normal things like tic tocs should never do it, but fast decents inverted and then slamming the pitch to it can do it with about anything.

Norman Ross Jr.
05-19-2008 02:01 AM
 
 
carzan
Veteran
Location: The Lone Star State

I did think about the Damping. However we just put in the infinivation dampers less than two weeks ago. the head is VERY tight. Some of the guys said they heard a pop about 15 seconds before the boom strike but i just chalked that up to a bunch of very shaken up airplane pilots who had never seen a heli destroy itself in the air.

the blade that appears to have been the one to strike does have a crack in it on the underside near the root but there's no telling when that crack appeared. For all I know the boomstrike caused the crack.

As I remember it he really wasn't doing anything out of the norm for his flying. I jusrt remember that the top of the disc was facing me and the heli was moving away from us as it did the pirouettes. I can't really picture the orientation of the bird just prior to the strike. and I didn't hear the earlier pop that the airplane guys were talking about.

The world may never know.
05-19-2008 02:17 AM
HOMEPAGE  
 
 
airboss
Elite Veteran
Location: OC ,california

if he was doing a fast tail walk it may have got a bind during the full neg pitch run, and popped a link.

OCRM....flyBlackstarr.org.
05-19-2008 02:55 AM
 
 
carzan
Veteran
Location: The Lone Star State

airboss,

Amazingly enough all links were still connected after the crash! Really I cant even find one that was bent! it was a really weird thing. I am working on it now and will have it back in the air by next weekend hopefully.
05-19-2008 03:39 AM
HOMEPAGE  
 
 
airboss
Elite Veteran
Location: OC ,california

I beleive you , they are the toughest darn links .did you bust a grip or mixing arm?

OCRM....flyBlackstarr.org.
05-19-2008 04:35 AM
 
 
carzan
Veteran
Location: The Lone Star State

Nope. He did hit throttle hold fairly quickly though.
05-19-2008 04:44 AM
HOMEPAGE  
 
 
Tyler
Key Veteran
Location: Chicagoland area

Piro...

Was the fast piro intentional or a surprise? If not planned, I would bet that the tail box screw came out and the tail box shifted/twisted, possibly driving the tail boom up into the main blades. The crack heard would have been that short 4mm bolt hitting the main blades.

Are the screws still holding the tail box to the tail boom? Any chips out of the main blades?

Tyler

Airtronics, YS Power, Switchglo ignitors, Jersey Modeler filled with Magnum
05-19-2008 04:51 AM
 
 
Futura SE
Veteran
Location: Fayetteville, Arkansas

Jay,
I am betting something did actually break prior to the crash. I bet the airplane pilots did actually hear something. Like you said for anything now it is a matter of the chicken or the egg argument. Which came first??? Mechanical failure causing crash or the other way around.

Norman Ross Jr.
05-19-2008 05:02 AM
 
 
thebignickey
Senior Heliman
Location: Marietta, GA

I witnessed the same thing happen with Matt Botos at IRCHA 2006.

He was also trying the Infinivation dampeners and heard a "tic" sound

and immediately landed. Upon inspection he found a ding in the boom

from where the blade had come into contact with the boom.

He immediately removed the Infinivation Dampeners and put in

something else. Needless to say, after seeing that I would not

run those dampeners. The N9 is not a machine that is known to

boomstrike very easily.
05-19-2008 05:44 AM
 
 
Long Nguyen
Senior Heliman
Location: Ho Chi Minh city, Vietnam

seven months flying my N9 doing all kinds of 3D but have never had a boom strike. I used the hyperings and lately have switched to use the infinavation dampeners for a month. Do you have "long ball mod" on your head?

Long Nguyen
My SHAVER is cutting rice!
05-19-2008 05:49 AM
HOMEPAGE  
 
 
ttrip06
Senior Heliman
Location: Central Pa

When you said you could seee the rotor disk prior to the boom strike, what direction was the wind coming from? How much wind was there? And how in comparsion to the wind did he rotate the model?

There were a few boom strike vids post last year by guys (top pilots), that had boom strikes for no obvious reason, that they associated back to the wind and the manuever direction.

Just a thought.

Tim
05-19-2008 02:06 PM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

carzan, are the infinavation dampeners broken?

Charles

Please stand by for faster service!
05-19-2008 02:11 PM
 
 
carzan
Veteran
Location: The Lone Star State

Long Nguyen K. - Yes he does have the long ball mod on his N9.

Chuckie - The dampers appear to be fine.


Guys, after much thought and some consultation via PM, I believe that he simply "caused " it with too much negative and cyclic input simultaneously. I do not believe the damping was poor or that anything broke prior to the boomstrike. the tail was still securely attached to the boom when I picked it up some 40 feet from the rest of the aircraft. I'll chalk this one up to a young aggressive pilot who simply got caught "speeding."

Thanks for all of your input! It's really great to have you fellas as a resource whenever I need you!

Jay
05-19-2008 03:50 PM
HOMEPAGE  
 
 
Futura SE
Veteran
Location: Fayetteville, Arkansas

This is not on track with Jay's problem, but a bit of info for you all.

Matt Botos said one very desirable thing about flying a flybarless heli is he has tried on purpose to do so and can not boom strike his flybarless N9. When you take the flybar off and get rid of the gyroscopic effect it causes the problem disappears. The flybar plays a major role in a boomstrike believe it or not. I found this info interesting. Curtis said the same thing about his flybarless Vibe.

Norman Ross Jr.
05-19-2008 07:04 PM
 
 
carzan
Veteran
Location: The Lone Star State

Quote 
When you take the flybar off and get rid of the gyroscopic effect it causes the problem disappears. The flybar plays a major role in a boomstrike

I've heard this also! Now if I could just unass the cash it would take to go flybarless the issue would be solved. May be christmas before Dylan gets to own a flybarless N9. LOL



But then, if this happens again, Christmas may come early!
05-19-2008 08:22 PM
HOMEPAGE  
 
 
Rymps
Veteran
Location: Indianapolis and Windsor CO

Very interesting. Matt alsa runs his head i think 1 inch or more closer to the boom than on flybar heads.
05-19-2008 10:54 PM
 
 
STUPINEER
Senior Heliman
Location: allen tx

I am new to the N9. what is the long ball mod?

gravity is king
05-20-2008 12:49 AM
 
 
carzan
Veteran
Location: The Lone Star State

Quote 
what is the long ball mod?

it is where you replace the balls on the seesaw and the ones on the arms on the grips with longer balls ( same as the ones on the swash). This mod helps to prevent binding and helps to reduce chances of link popping off. It also gives you more degrees of cyclic and when we did it to Dylan's bird it gave him more pitch.

Warning - there is more to it than just replacing the balls you have to use spacers and shave the threaded end of the balls just a little so as not to interfere with movement of the flybar.

Jay
05-20-2008 03:40 AM
HOMEPAGE  
 
 
carzan
Veteran
Location: The Lone Star State

where is Allen TX?
05-20-2008 03:42 AM
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Synergy R/C Synergy N9 > Mid-Air Boomstrike
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