Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

fin

Matronics Email Lists Forum Index -> RV9-List

View previous topic :: View next topic

Author Message

chenoweth(at)gwi.net
Guest

Posted: Sun Apr 29, 2007 3:22 pm Post subject: fin

Let me start with the questions first and then the  story.

  

 The question:  Is the rear spar of the fin  straight enough when a straight edge laid along the hinge brackets is aft of the  center one by about 1/32 inch?  

 How about if it's out of line by more than 5/64 but  less than 3/32?  

 These are apparently my two choices.

  

 The story:

 If I mount the fin per the drawing, front spar  ahead of hold-down bracket and fin pushed forward so that the hold-down bracket  just contacts the flanges on the fin's bottom ribs, the rear fin spar is firmly  against the 712 bulkhead but the out of true is the over 5/64 amount I mentioned  above.  Which, by the way, is the amount it turned out to be out of true  when I built it.  At that point the rudder seemed to work ok with  it.

  

 If, however, I mount the fin with the forward spar  behind the hold-down bracket and with the bracket just touching the flange of  the fin's bottom rib, the rear fin spar does not seat against the 712 - it's  about 1/32 aft of it at its top.  But I get the less than 1/32 out-of-true  measurement in the hinge line.  Based on the way I'm making the up elevator  stop having the rear fin spar not contact the 712 is not a problem because I can  position the stop slightly aft to make good contact with the spar and still have  it function properly with the elevator horns.

  

 Any answers/comments you'd care to make would be  very much appreciated.

  

 Bill

 RV9

 Albion, Maine

   [quote][b]

- The Matronics RV9-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV9-List

kayce33(at)earthlink.net
Guest

Posted: Sun Apr 29, 2007 6:01 pm Post subject: fin

Hi Bill,

 I checked mine with a drilled acorn/cap  nut, string thru the drilled hole with a weight.

 Mine came out with about a 1/64th" off  center error.....seems easier than a straight edge & worked with flaps  too.

 Harold, RV9A Fuselage  wiring

 [quote]   ---

- The Matronics RV9-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV9-List

chenoweth(at)gwi.net
Guest

Posted: Wed May 02, 2007 3:17 am Post subject: fin

Harold,

 Sorry for the delay in thanking you for the  advice.  I ended up discussing the situation with Van's.  Their  position was that it had to be straight.  The suggestion was to raise the  rear spar (since mine is a tailwheel version I could only do that about  1/16 due to edge margin issues) and/or to trim some off the 981 front  bracket.  I ended up doing both plus filing some off the top hinge brackets  so they were the same dimension from hole to aft edge as the two lower ones so  that the straight edge technique would produce accurate results.  After all  that I'm between .005 off to absolutely straight.  Van's said the .005 was  close enough.  Haven't drilled yet.

 Bill

 [quote]   ---

- The Matronics RV9-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV9-List

kayce33(at)earthlink.net
Guest

Posted: Wed May 02, 2007 5:09 am Post subject: fin

Hi Bill, 

 Sounds as if your accuracy was superior to mine.  You must do good work.

 Harold

 [quote]   ---

- The Matronics RV9-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV9-List

bill(at)repucci.com
Guest

Posted: Wed May 02, 2007 5:59 pm Post subject: fin

Bill,

  

 Don't  forget that you have to trim the front spar before installing  it.

  

 For  some reason Van's doesn't mention this until after you have built the VS.   It is anyone's guess as to why then but it would be easier to do before riveting  that thing together.

  

 Bill

  

 

 --

- The Matronics RV9-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV9-List

chenoweth(at)gwi.net
Guest

Posted: Thu May 03, 2007 4:58 am Post subject: fin

Bill, 

 No issue there - I had it trimmed.  The  biggest problem seemed to be that the 981 was bottoming on the fin rib flanges  before the rear spar was straight.  Also, the fact that this is a tailwheel  version severely limits the amount that I could move the rear spar up.   Taken together I didn't have a lot of slack to get the amount of forwardness I  needed to get the rear spar straight.  As you surely have noticed the  instructions re this are hamburger.  My primary concern was not knowing  just how straight the hinge line had to be.  Ken at Van's generally  dismisses my concerns about tolerances but in this case was adamant that it  needed to be straight so I took it seriously.  

  

 Reacting to Harold's comment I must say that I have  pretty high expectations but only moderate skill.  This combination can  produce a fair amount of anxiety in situations like the current one.  But,  sometimes I luck out - often I don't.

  

 Bill

 ---

- The Matronics RV9-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?RV9-List

Display posts from previous:

	Matronics Email Lists Forum Index -> RV9-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum