VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-12
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 11-03-2017, 02:18 PM
Tacco Tacco is offline
 
Join Date: Jan 2017
Location: White Salmon, WA
Posts: 11
Default Tapping Plexiglass Rear Window - Really?

About to fit and install the back window. Plans say to tap both the window and the rollover structure for the attachment screws. As paranoid as I am to avoiding any sharp edges on plexigalss canopy/window, I am perplexed as to why I should tap both the plexiglass and the underlying structure. Seems to me that I will introduce a helix of sharp edges at each screw hole by doing so...and what purpose does it serve versus a smooth hole? How did this go for those that have done this?
Reply With Quote
  #2  
Old 11-03-2017, 02:23 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,114
Default

Unless things have changed the plex is not tapped. My plans said countersink the plex, not tap it.
Reply With Quote
  #3  
Old 11-03-2017, 03:01 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,970
Default

Things have changed (at least from what the lexan rear window install procedure was, and I don't think the plans say to countersink either because truss head screws are used).
Years of experience has shown that one thing that is a big challenge for many builders is threading/tapping a hole straight.

More recent plans sections (RV-14 and now acrylic rear window plans for RV-12) have you drill a hole in the window and the metal structure (in this case rollbar) and then tap with the window in place. The window is soft and the tap will start easily and self straighten when it gets to the metal structure.
After all the holes are threaded, the window is removed and all the holes in the window get enlarged to appropriate size for the screws that are used.

You did read the entire section first before starting to get an understanding of will be happening didn't you?
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #4  
Old 11-03-2017, 04:13 PM
pstraub's Avatar
pstraub pstraub is offline
 
Join Date: Nov 2015
Location: Galt, CA
Posts: 53
Default

Hi Scott, I was just going to try and put the OPs mind at ease, I remember tapping all those holes in the plex rear window and it worked out fine, just as it says on page 25A-03, step 2. When I read your response about later enlarging the tapped holes, I didn't remember doing that step. I think you actually leave the front row of holes (in the rear window) tapped, they don't get touched again. The rest of the holes in the rear window get final drilled to #27. I could have missed it though....bottom line, the tapped holes in the plex are holding up fine on my install. Certainly no sign of cracks at 43.0 hours
__________________
Paul Straub, First Flight May 5, 2017
50 hours and counting.....
**2017 dues paid**
Reply With Quote
  #5  
Old 11-03-2017, 04:27 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,970
Default

Quote:
Originally Posted by pstraub View Post
Hi Scott, I was just going to try and put the OPs mind at ease, I remember tapping all those holes in the plex rear window and it worked out fine, just as it says on page 25A-03, step 2. When I read your response about later enlarging the tapped holes, I didn't remember doing that step. I think you actually leave the front row of holes (in the rear window) tapped, they don't get touched again. The rest of the holes in the rear window get final drilled to #27. I could have missed it though....bottom line, the tapped holes in the plex are holding up fine on my install. Certainly no sign of cracks at 43.0 hours
Paul, Step 6 has you final drill the remaining holes in the window to #27 (by remaining it basically mean all holes because the ones common to the aft skin were drilled #30 and the ones common to the roll bar were drilled 36 and tapped).
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #6  
Old 11-03-2017, 05:04 PM
pstraub's Avatar
pstraub pstraub is offline
 
Join Date: Nov 2015
Location: Galt, CA
Posts: 53
Default

Ahh, OK. I definitely missed that. I did see that step 6 said to 'Final drill' the #30 holes, so just assumed that was all. It's kind of funny, the forward rear window holes get 'final' drilled twice....once in step 2 and again in step 6.
__________________
Paul Straub, First Flight May 5, 2017
50 hours and counting.....
**2017 dues paid**
Reply With Quote
  #7  
Old 11-03-2017, 05:11 PM
mike newall's Avatar
mike newall mike newall is offline
 
Join Date: Jan 2005
Location: Yorkshire, England
Posts: 1,405
Default

Having just got to this bit, I also wondered.....

Sometimes, instructions of some importance get hidden or put at the end of a piece and can be easily over read.

As plans get revised, it would be great to collect some of the OMG gotchas and box them on the side of the particular print or passage in the instructions. Wouldn't take long and would be very helpful.

For an example - the quoting of all the part numbers in full means that sometimes you begin to speed read (bit like Tolkien books) and some of these little tidbits get missed
__________________
"I add a little excitement, a little spice to your lives, and all you do is complain!" - Q

Donated in 2017
Reply With Quote
  #8  
Old 11-03-2017, 05:30 PM
Mel's Avatar
Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 9,644
Default BUILDER HINT!!!!!!!

Quote:
Originally Posted by mike newall View Post
Having just got to this bit, I also pondered.....
Sometimes, instructions of some importance get hidden or put at the end of a piece and can be easily over read.
As plans get revised, it would be great to collect some of the OMG gotchas and box them on the side of the particular print or passage in the instructions. Wouldn't take long and would be very helpful.
For an example - the quoting of all the part numbers in full means that sometimes you begin to speed read (bit like Tolkien books) and some of these little tidbits get missed
NEVER "SPEED READ" PLANS!
__________________
Mel Asberry..DAR since last century
A&P/EAA Tech Counselor/Flight Advisor
Specializing in Amateur-Built and Light-Sport Aircraft
<n168tx(at)flytx.net>
North Texas (8TA5)
RV-6 Flying since 1993
175hp O-320
3-Blade Catto (since 2003)
FRIEND of the RV-1
Eagle's Nest Mentor
Reply With Quote
  #9  
Old 11-03-2017, 06:05 PM
Tacco Tacco is offline
 
Join Date: Jan 2017
Location: White Salmon, WA
Posts: 11
Default

Thanks guys.

I think Paul had it right the first time though. The holes in the roll bar and window were already "final drilled" to #36 in step 2. By "Final drill #27 the remaining #30 holes" in Step 6, I'm pretty sure it means the ones in the aft turtle deck skin and window in that area. Since they are #30. The ones associated with the roll bar were never drilled to #30 anyway. At least that my interpretation of the english.

All that said, here is an indication that Scott may be right with respect to Van's intent - the drawing, Fig. 2 25A-04, seems to show enlarged smooth holes in both areas of the window.

Firing off a question for Van's Support.

Last one for you guys though, will a plexiglas bit do well in the aluminum roll bar? Did you swap to a regular bit when you got that deep?
Reply With Quote
  #10  
Old 11-03-2017, 06:11 PM
daveyator daveyator is offline
 
Join Date: Jan 2011
Location: adelaide, south australia
Posts: 130
Default

Your plexi bit will have no problem drilling through the roll bar, and later the front canopy bow.
I think you may find that the screws will not fit the #36 holes you 'match drilled' prior to tapping. The screw holes need the extra clearance to allow for the different expansion rates between plexi and the screws.
Cheers, DaveH
120485

Last edited by daveyator : 11-03-2017 at 06:20 PM. Reason: More info
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 10:02 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.