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Old Feb 04, 2010, 10:02 PM
sidneyw is offline
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Share your best solution-Century Swift 16 skid/strut & others


All Swift owners know this .... the skid and chicken dance.

If you could share available options/solutions .... best option/solution.

Anything related to Swift is welcome.
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Last edited by sidneyw; Feb 21, 2010 at 11:15 PM.
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Old Feb 04, 2010, 11:24 PM
Fred Bronk is offline
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A right setup and there are no issues. IE; a balanced head and little or no neg pitch on spoolup.
Old Feb 04, 2010, 11:41 PM
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Originally Posted by Fred Bronk View Post
A right setup and there are no issues. IE; a balanced head and little or no neg pitch on spoolup.
I could manage the spool up without much shake ; it is the spooling down that is terrible.
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Old Feb 05, 2010, 12:33 AM
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here's being square-


I've had shakes so violent on spooldown that it snapped swash-to-bladegrip linkages and cracked brand-new carbon blades. It turned out that my blade grips were too tight and had messed up settings in my Sk360 FBL controller.

The "shakes" is also known as ground resonance. That article explains it fairly well, but some 2 bladed helis (such as the Swift) do in fact have lead-lag hinges and are thus susceptible. There is a very dramatic video of this on YouTube with a Chinook tied down to the deck as a demonstration- it self-destructs.

One thing that can almost guarantee the shakes is having one main blade grip a little tighter than the other. Because of this or any other reason that causes one blade to lead/lag the other results in an imbalance and oscillation.

A technique I use is to avoid this is overtighten the main grips a bit, work the blade fore and aft a few times to "break it in," then loosen the grip to where I think it should be- evenly for both blade grips. If they are too tight, then they won't be able to straighten themselves out and you will almost certainly get the shakes.

Like that article says, all things have a natural frequency of vibration. The spindly oem Swift gear struts (CNE512) are too springy for the typical weight load of a Swift. Most any 550 to 600 and .30 size nitro heli's gear struts will work fine, but you may have to drill new holes to line up with the frame tabs. You might also have to use spacers to elevate the tail for it to clear if they are lower profile. I've used simple standoffs and even tried r/c buggy shock absorbers. Depending on what battery pack you use or how you secure it to the frame will have to be accomodated for.

The easiest cure are a set of Swift 620 heavy duty struts (CNE612) since the bolt holes line up out of the bag and have offset bolt holes for the tailboom supports with no battery pack mounting mods. I'm using these on my Swift 550 and get no shakes. My other favorite is the T-Rex 600 strut (H60126). These are low profile, so you'll have to elevate the tail to get it out of the grass by either using a spacer over the rear strut. You can also elevate the tail itself, but that's a bit more work. Also, they work best if you mount the battery pack somewhere other than hung below.
Old Feb 05, 2010, 01:09 AM
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I have 2 (FBL), 3, 4 and 5 bladed heads in scale. I understand blade grip and how tight they should be. I'd say the skid design, or the lack of.

I have read the original Swift 16 thread for more than two years and after Chris started the Part Two. I've read your Swift start up at the beginning, no stranger here just did not register at the forum until later date and don't like bragging. This is a hobby which I can build by myself or with others who happen to be "friendly", like golf.

I was hoping to find out if anyone make their own skid; should not be much to it. There are tricks to make scale fuselage free from vibration.

Anyway, I was going to get the new skid to try out. This one will go into a Cobra in Spring.

The carbon fiber servo rod and the support bind easily; the new slider and thicker links need a good workout; together they could mess up gyro setup enhancing tail bounce. I am happy with it other than the chicken dance which I know I could resolve. What I was unhappy about was a post outside the thread title parameter slightly and warned by someone other than the thread starter. Being square here didn't help, and I am not sorry.
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Last edited by sidneyw; Feb 05, 2010 at 01:15 AM.
Old Feb 05, 2010, 06:07 AM
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Are you spooling up and down with no pitch?
Old Feb 05, 2010, 06:38 AM
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Quote:
Originally Posted by sidneyw View Post
I have 2 (FBL), 3, 4 and 5 bladed heads in scale. I understand blade grip and how tight they should be. I'd say the skid design, or the lack of.

I have read the original Swift 16 thread for more than two years and after Chris started the Part Two. I've read your Swift start up at the beginning, no stranger here just did not register at the forum until later date and don't like bragging. This is a hobby which I can build by myself or with others who happen to be "friendly", like golf.

I was hoping to find out if anyone make their own skid; should not be much to it. There are tricks to make scale fuselage free from vibration.

Anyway, I was going to get the new skid to try out. This one will go into a Cobra in Spring.

The carbon fiber servo rod and the support bind easily; the new slider and thicker links need a good workout; together they could mess up gyro setup enhancing tail bounce. I am happy with it other than the chicken dance which I know I could resolve. What I was unhappy about was a post outside the thread title parameter slightly and warned by someone other than the thread starter. Being square here didn't help, and I am not sorry.
i'm not new to helis either and couldnt rid my swift of the shakes,tried raptor skids,shorter/longer blades all sorts of blade tightness,even tried bracing the frame to no avail.
just resonance of a poorly designed frame IMO.
crazy how my HK 500GT $67 heli spools up and down with pitch and doesnt even vibrate or move.
Old Feb 05, 2010, 07:55 AM
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Quote:
Originally Posted by sidneyw View Post
IWhat I was unhappy about was a post outside the thread title parameter slightly and warned by someone other than the thread starter. Being square here didn't help, and I am not sorry.
Just an attempt to be helpful to get your question answered the best way possible and keep the other thread on topic. I knew it might get interpreted a little sideways, but I'm willing to accept that given the limitations of this medium. I was unaware of your experience since you didn't volunteer that information in your original post.

Best of luck finding a solution.
Old Feb 05, 2010, 09:07 AM
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Originally Posted by Greybird View Post
Are you spooling up and down with no pitch?
Yes, I have.

Quote:
Originally Posted by brodjack View Post
i'm not new to helis either and couldnt rid my swift of the shakes,tried raptor skids,shorter/longer blades all sorts of blade tightness,even tried bracing the frame to no avail.
just resonance of a poorly designed frame IMO.
crazy how my HK 500GT $67 heli spools up and down with pitch and doesnt even vibrate or move.
Yes, my EXI500 has absolutely no vibration at all even if I want it to vibrate.

Others have successfully eliminate shake in scale fuselage; I am sure it has to do with frame to strut or fuselage mount. You can't even spool up to speed with such vibration in scale.
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Old Feb 05, 2010, 10:11 AM
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With that vibration, some people have it, some don't. I have 3 Swifts. Did you lube the dampers? Have tried different blades? Are the blades balanced perfect? Center of gravity the same on each blade? Some rotor heads had issues with the thrust bearings binding. Make sure that is not an issue. Too slow of spool-up has been known to cause shakes. Try spooling up faster. Is the tail smooth, blades balanced, etc? That can also be transferred through the stuts and cause shaking. I have that right now on a crash re-build that I used a Logo tail to fix it. I think the Swift might be just trying to shake those parts off. I have some Century parts to swap out. Should fix it. I have that landing gear to try. It requires dremmeling the frame attachment points flat, and some canopy clearancing to make them work.
Old Feb 05, 2010, 10:15 AM
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Where did you get your kit? Maybe it is old stock? Post a picture. The newer kits have thicker landing gear. Sorry for rambling. Don't get discouraged. The Swifts are a lot of fun. I am going to buy a 4th when that new one is released.
Old Feb 05, 2010, 10:18 AM
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Spooling up fast is how I manage not to have the shake. Putting in some work does not bother me at all. In fact, being 1st timer Swift operator, I found a few undesirables.

1) Tail slider linkages
2) Tail servo rod and rod guide

I lost the tail case screw/nut only after two trimming flights. I own one because the low tail boom location good for Huey and Cobra fuselages.

It is an older kit never flown I got. I will get the new struts order today. No, I am not at all discouraged. Part of the fun in building, owning and flying.

Like marriage, perfect is when you work on it daily.
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Old Feb 05, 2010, 10:27 AM
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BTW, one of the struts broke off this morning. I have been trimming it in the last 4 days in 15 - 25F for about 6 flights. Asphalt driveway and the cold surely no good on plastic.
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Old Feb 05, 2010, 10:31 AM
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Their you go. Even the newer, not 620 gear will fix it. The newer kits also have bigger links on the tail slider. I have one modified to use Logo links, the other 2 use slider parts from the Hawk.Does your frame have the holes on the bottom for the 3rd bearing upgrade? If not. the new frames are a giant improvement. Much stiffer. Good luck!
Old Feb 05, 2010, 11:16 AM
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Originally Posted by Greybird View Post
Their you go. Even the newer, not 620 gear will fix it. The newer kits also have bigger links on the tail slider. I have one modified to use Logo links, the other 2 use slider parts from the Hawk.Does your frame have the holes on the bottom for the 3rd bearing upgrade? If not. the new frames are a giant improvement. Much stiffer. Good luck!
Do you mean This new struts?
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