|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

06-07-2010, 05:01 PM
|
 |
|
|
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
|
|
7A wing bolt orientation
The only drawing I can find in the plans regarding wing bolts is for a 7, not an "A" model. Obviously on the taildragger, having all bolts oriented from front to back is certainly not a problem. But with the gear weldments, some of the bottom bolts must be oriented back to front, right?
Also, I'm torquing the rear spar attach bolt and looking up the proper torque to use. Is this bolt a fine thread or course thread bolt and how does one distinguish the two?
Last edited by LettersFromFlyoverCountry : 06-07-2010 at 05:58 PM.
|

06-07-2010, 07:07 PM
|
|
|
|
Join Date: Jan 2005
Posts: 1,009
|
|
Check out the Fastener Section at Your Local Hardware
U.S. fasteners are specified in "threads per inch". The fine thread versions are the ones with greater Thread Per Inch count. IIRC, there are no coarse threaded fasteners used anywhere in the airframe. Regarding bolts facing fore or aft, the orientation should be to allow the most accessible tightening of the nut. Never tighten the bolt, as you'll get an unreliable torque/clamp results due to the added friction.
Terry, CFI
RV-9A N323TP
|

06-07-2010, 07:19 PM
|
 |
|
|
Join Date: Oct 2008
Location: Schaumburg, IL
Posts: 2,053
|
|
Bob,
I had to put some heads forward and some aft. It was not possible to torque the nuts all facing the same direction.
__________________
Tony Phillips
N524AP, RV 9 (tail wheel)
|

06-07-2010, 08:51 PM
|
 |
|
|
Join Date: Apr 2006
Location: Tauranga, New Zealand
Posts: 27
|
|
Bob
DWG11 shows all the bolt heads aft. Washers under the nuts for the top bolts and washers under the bolt heads for the lower ones. Be careful inserting the lower outer big bolts. If they go in too far before you get the nut started you will have a problem trying to back them out again. Don't ask me how I know
Jim Talbot
New Zealand
RV7A
Flying!
|

06-07-2010, 11:35 PM
|
|
|
|
Join Date: Nov 2005
Posts: 1,256
|
|
Quote:
Originally Posted by terrykohler
U.S. fasteners are specified in "threads per inch". The fine thread versions are the ones with greater Thread Per Inch count. IIRC, there are no coarse threaded fasteners used anywhere in the airframe.
|
Correction...on the -7A, the socket head cap screws that go through the gear leg at the wheel to hold the brake flange, etc., take a 1/4-20 nut. The shank of the screw is 5/16, the threads are 1/4-20. Torque to 1/4-20 specs, not 5/16. Ask me how I know this.
This is the only place I found on the airframe with coarse threads...
__________________
Steve "Flying Scotsman"
Santa Clarita, CA
PP-ASEL, ASES, Instrument Airplane
RV-7A N660WS flying!
#8,000
|

06-08-2010, 07:45 AM
|
 |
|
|
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
|
|
Quote:
Originally Posted by jimski9
Bob
DWG11 shows all the bolt heads aft. Washers under the nuts for the top bolts and washers under the bolt heads for the lower ones. Be careful inserting the lower outer big bolts. If they go in too far before you get the nut started you will have a problem trying to back them out again. Don't ask me how I know 
|
But I don't believe Drawing 11 is referencing an "A", it's referencing a tail dragger without the landing gear weldments.
|

06-08-2010, 07:53 AM
|
 |
|
|
Join Date: Nov 2005
Location: Asheville, NC
Posts: 2,692
|
|
AN hardware is fine as frog hair
Hey Bob,
It is my understanding and experience that all common AN bolt hardware would be classified as "fine" threads or "UNF".
I know there are exceptions such as engine fasteners and #8 and smaller screws but for AN3 bolts and above, I think they are all fine thread.
__________________
Bill Pendergrass
ME/AE '82
RV-7A: Flying since April 15, 2012. 850 hrs
YIO-360-M1B, mags, CS, GRT EX and WS H1s & A/P, Navworx
Unpainted, polished....kinda'... Eyeballin' vinyl really hard.
Yeah. The boss got a Silhouette Cameo 4 Xmas 2019.
Last edited by rzbill : 06-08-2010 at 07:57 AM.
Reason: screw note
|

06-08-2010, 08:50 AM
|
|
|
|
Join Date: Mar 2005
Posts: 179
|
|
Pretty sure DWG 11 applies to the "A" models as well. In fact, I don't see any reason to have the washers under the lower bolt heads on a tail dragger.
Quote:
Originally Posted by jimski9
Be careful inserting the lower outer big bolts. If they go in too far before you get the nut started you will have a problem trying to back them out again. Don't ask me how I know 
|
This is good adivce!
__________________
Jim Percy
SoCal
FFI Wingman
RV-7A, XP-O-360
|

06-08-2010, 03:04 PM
|
 |
|
|
Join Date: Jan 2005
Location: St. Paul, MN.
Posts: 4,792
|
|
Final ruling from Van's -- the orientation of the bolt doesn't matter. Whatever makes it easiest to torque the nut.
|

06-08-2010, 08:48 PM
|
 |
|
|
Join Date: Dec 2006
Location: Paso Robles, CA
Posts: 1,177
|
|
Think about it / A little more info!
Quote:
Originally Posted by Bob Collins
Final ruling from Van's -- the orientation of the bolt doesn't matter. Whatever makes it easiest to torque the nut.
|
Thanks Bob,
Vans is correct (no surprise)
When a representative sample of these bolts are destructively tested after manufacture, they are supposed to break at or above a certain tension. The only acceptable failure point is the root of the threads close to the transition area where the unthreaded shank and the threads meet.
That is the tensile test.
The shear test applies the the full cylindrical portion of the unthreaded shank, depending on the fastener it may be cut in two with a special shear jig or put in a special jig to just proof load the shank.
The bottom line is a bolt will be just as strong either way it is installed.
If a nut and bolt combination would fail due to installation direction of the bolt there would be due to a serious mismatch of fastener to structure.
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 05:36 AM.
|