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  #1  
Old 03-03-2018, 07:54 PM
Brett H Brett H is offline
 
Join Date: Oct 2013
Location: Columbus, Indiana
Posts: 27
Default Canopy Struts Are Rubbing the Canopy Frame

I am currently in the process of trying to get my canopy frame to fit.

In doing so, I have noticed that the inside edge of the canopy struts rub the canopy frame when the canopy frame is closed. The paint on the inside edge of the struts has been worn off. Also, it is not possible to get a piece of paper to slide between the strut and the canopy frame when closed. Further, the alignment between the canopy frame and the fuselage differs if the struts are or are not installed.

Anyone seen this before? If so, what did you do about it?

Thanks.

Brett Herrick
Columbus, IN
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  #2  
Old 03-04-2018, 05:13 AM
mike newall's Avatar
mike newall mike newall is offline
 
Join Date: Jan 2005
Location: Yorkshire, England
Posts: 1,685
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You have shim/washer options in the print to help in this area. Go back a page and look.

I take it you have the struts on the right way round...
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  #3  
Old 03-04-2018, 11:13 AM
Brett H Brett H is offline
 
Join Date: Oct 2013
Location: Columbus, Indiana
Posts: 27
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Mike:

First, thanks for your response.

Yes, the "rod end" of the strut is attached to the fuselage and other end is attached to the canopy.

Regarding the shim washer described in step 3 of sheet 34-03, isn't that to provide clearance between the forward arms of the canopy frame and the upper fuselage skin? Yes, I had to add a thin washer on each side.

I am installing the new struts with the metal ends. One thing that I am not positive of is which version of the C-1204 bushing is to be used. I believe that steel ended struts use the version of the C-1204 that has a tapered transition between the two outside diameters rather than no transition. But, I have the same issue with both bushings.

Any other thoughts would be appreciated.

Brett H
Columbus, IN
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  #4  
Old 03-04-2018, 12:20 PM
mike newall's Avatar
mike newall mike newall is offline
 
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Location: Yorkshire, England
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On the front mount where the bronze bush sits, we had to pack out with washers about 2 or 3 to get everything to clear - both skin and strut. Can't get a snap as everything is tucked into the glass fairing now.

You need a snap from someone else who is just fitting the canopy.
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  #5  
Old 03-04-2018, 07:32 PM
Brett H Brett H is offline
 
Join Date: Oct 2013
Location: Columbus, Indiana
Posts: 27
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Mike:

On each side of the canopy frame I put two standard thickness washers between the canopy frame bushing and the fuselage, this didn't reduce the contact between the strut and the bottom of the canopy frame arm. So, I removed them.

Next I put a standard thickness washer between the C-1204 bushing and the canopy frame arm on each side. This reduced the interference. But, didn't resolve it and means that that AN509 screw will need to longer (i.e. stick out more).

I'm starting to think that the interference / rubbing is going to happen and that the best solution is to round the bottom edge of the canopy frame arm so that the strut has smooth surface to ride up on. Or there is something wrong with the parts that I have.

Brett H
Columbus, IN
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  #6  
Old 03-13-2018, 08:21 PM
DaveWelch DaveWelch is offline
 
Join Date: Mar 2005
Location: Huntsville, AL
Posts: 321
Default Don't cut any metal yet

Quote:
Originally Posted by Brett H View Post
Mike:

On each side of the canopy frame I put two standard thickness washers between the canopy frame bushing and the fuselage, this didn't reduce the contact between the strut and the bottom of the canopy frame arm. So, I removed them.

Next I put a standard thickness washer between the C-1204 bushing and the canopy frame arm on each side. This reduced the interference. But, didn't resolve it and means that that AN509 screw will need to longer (i.e. stick out more).

I'm starting to think that the interference / rubbing is going to happen and that the best solution is to round the bottom edge of the canopy frame arm so that the strut has smooth surface to ride up on. Or there is something wrong with the parts that I have.



Brett H
Columbus, IN
I wouldn't cut or shave any metal yet until you're certain all else is according to plan. I don't recall the interference you describe being often discussed.
Can you post a picture of your strut attachments (top and bottom) and where "the rub" is?

Dave
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  #7  
Old 03-14-2018, 11:34 AM
Brett H Brett H is offline
 
Join Date: Oct 2013
Location: Columbus, Indiana
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To restate the issue so that we are all on the same page, in the process of fitting my canopy frame to the fuselage I discovered that the canopy struts were rubbing the canopy frame arms as the canopy is being closed.

I am using the new steel struts and the new bushings that are to be used with the steel struts. The new bushings can be identified from the old bushings is that the transition between the two outside diameters is a conical taper rather than a sharp transition.

The rubbing of the canopy struts has two impacts. First, it changes fit / location of the rear end of the canopy frame with the fuselage. Second, this rubbing can felt / heard when the canopy is almost closed and it has rubbed the paint off of almost all of the full length of the canopy strut body where it rubs the canopy frame arm. This lack of clearance is also demonstrated by the inability to get a piece of paper between the body of the canopy strut and canopy strut arm.

Van’s has recommended the following three potential corrections (i.e. paraphrased):
1.) Modify the flange by bending it inward to provide additional clearance
2.) Reduce edge and/or weld by filing, grinding, sanding, buffing and so on,
3.) Add the washer height needed under the two bushings. The “reduced area” of the washer is not a concern.

Installing a standard washer (i.e. 1/16 inch thick) under both bushings to space the canopy strut outboard has improved but not resolved the rubbing.

My intention is to use a combination of filing and washer height to achieve the clearance. Namely, using the 1/16 inch washer thickness, I will attempt to get the needed clearance by filing. If this leads me needing to remove more of the weld than I am comfortable with, I will add to the washer thickness.

If you would like, I can send pictures.

Brett H
Columbus, IN
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