Wing attach bolts
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Wing attach bolts
Does it matter which direction they are installed?
I'm having a discussion with my mechanic and he says they are installed incorrectly (that is with the bolt facing the rear of the aircraft). He feels that the bolt should face the front of the aircraft.
I'm in a quandry because my 140 has the rear two bolts facing the back of the aircraft.
I'm having a discussion with my mechanic and he says they are installed incorrectly (that is with the bolt facing the rear of the aircraft). He feels that the bolt should face the front of the aircraft.
I'm in a quandry because my 140 has the rear two bolts facing the back of the aircraft.
1952/1996 C170B Turbo. Why? Because, thats why.
CFI/CFII at KDYL
CFI/CFII at KDYL
Re: Wing attach bolts
I was told the heads are front, therefore if the nuts come off the rear, they will not work out.
John
John
John Hess
Past President 2018-2021
President 2016-2018, TIC170A
Vice President 2014-2016, TIC170A
Director 2005-2014, TIC170A
N3833V Flying for Fun
'67 XLH 900 Harley Sportster
EAA Chapter 390 Pres since 2006
K3KNT
Past President 2018-2021
President 2016-2018, TIC170A
Vice President 2014-2016, TIC170A
Director 2005-2014, TIC170A
N3833V Flying for Fun
'67 XLH 900 Harley Sportster
EAA Chapter 390 Pres since 2006
K3KNT
Re: Wing attach bolts
The bolt head should be forward and the nut on the aft side.
Re: Wing attach bolts
When I got my plane the bolts were installed with the heads forward. What that causes is the aileron cable on the right side to rub on the bolt. Whoever installed the bolts put the aileron cable and the carry through cable on the same pulley to keep the cable from rubbing. When I found two cables on the same pulley I removed the one that didn't belong and then found why the two cables were on the same pulley. Researching the parts manual figure 7 (B model) showed the bolt head to the rear. Bought new bolts for both sides and put them in head aft and problem was fixed.
Walt Weaver
Spencer Airport (NC35)
Spencer Airport (NC35)
Re: Wing attach bolts
Both the 170 IPC and the 100 series service manual show bolt heads aft, nuts forward. Your mechanic will discover a clearance issue with the windshield if he tries to install the front spar bolt head forward; he can get it in, but not without scuffing the glass or binding in the hole for the first 1/8-1/4" of penetration.
As stated above, there can be clearance issues with the aileron cable if the rear spar bolt is installed head forward, nut aft.
As stated above, there can be clearance issues with the aileron cable if the rear spar bolt is installed head forward, nut aft.
Del Lehmann
Mena, Arkansas
Mena, Arkansas
Re: Wing attach bolts
oops, I must have been looking at my book upside down?
- Brad Brady
- Posts: 745
- Joined: Fri Feb 29, 2008 2:54 am
Re: Wing attach bolts
I found the same thing years ago...Common sense tells you to install the bolts to the rear.....clearance, and the IPC says different.....When in doubt follow the IPC......The Feds will be on your side then .....Bradwingnut wrote:Both the 170 IPC and the 100 series service manual show bolt heads aft, nuts forward. Your mechanic will discover a clearance issue with the windshield if he tries to install the front spar bolt head forward; he can get it in, but not without scuffing the glass or binding in the hole for the first 1/8-1/4" of penetration.
As stated above, there can be clearance issues with the aileron cable if the rear spar bolt is installed head forward, nut aft.
-
- Posts: 278
- Joined: Tue Aug 09, 2005 9:49 am
Re: Wing attach bolts
My first annual my mechanic noticed the right side bolt was inserted from the front, nut to the rear. Like previously mentioned that will cause the aileron cable to rub on the nut. So someone had constructed a little aluminum arm and riveted a small phenolic plate to that. All secured to my wing in a fashion to hold the cable away from the nut. He had me remove all that and turn the bolt around.
Corey
'53 170B N3198A #25842
Floats, Tundra Tires, and Skis
'53 170B N3198A #25842
Floats, Tundra Tires, and Skis
Re: Wing attach bolts
I took lots of pictures back when I was shopping for a 170. Looking through those pictures today I found this. Notice anything wrong?
Another one.
Another one.
Re: Wing attach bolts
The A and B IPCs correctly demonstrate the bolt-heads AFT of the spar, with the nuts FWD.Brad Brady wrote:I found the same thing years ago...Common sense tells you to install the bolts to the rear.....clearance, and the IPC says different.....When in doubt follow the IPC......The Feds will be on your side then .....Bradwingnut wrote:Both the 170 IPC and the 100 series service manual show bolt heads aft, nuts forward. Your mechanic will discover a clearance issue with the windshield if he tries to install the front spar bolt head forward; he can get it in, but not without scuffing the glass or binding in the hole for the first 1/8-1/4" of penetration.
As stated above, there can be clearance issues with the aileron cable if the rear spar bolt is installed head forward, nut aft.
The "view" of the "exploded" area is from inboard-towards-outboard, or viewing FROM the cabin/fuselage. This is confirmed by noticing the view presented of the fuel-gauge.
The "ragwing" C-170 IPC depicts the forward-spar bolt-head FWD. I could not find an exploded view of the rear spar attach in the 170 IPC.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
Re: Wing attach bolts
Is it possible to replace these bolts without jigging, removing or supporting the wing?
Exactly how should one go about replacing them?
Exactly how should one go about replacing them?
Bruce Shipp
former owners of N49CP, '53 C170B
former owners of N49CP, '53 C170B
Re: Wing attach bolts
It's handy to have a another person to assist in just stabilizing the wing to prevent it from shifting, assuming you will replace one bolt at a time. Since the wing spars nest into the carrythru fittings, the wing won't fall out, but it can shift a bit. You can find some old bolts, grind the threads off, then grind a slight taper (bullet) on the shank, use it to drive the old bolt out. It will prevent shifting even if you only drive it in about half way. then insert new bolt to drive out your bullet.4-Shipp wrote:Is it possible to replace these bolts without jigging, removing or supporting the wing?
Exactly how should one go about replacing them?
Index mark the eccentric bushings before removing the aft spar bolts. I like to remove eccentric on the forward side (it'll probably fall out when you drive the bolt in anyway). I do this so that after the bolt is installed with aft eccentric in position (properly indexed) you can slide the forward eccentric onto the bolt, over the threads, and slide it while rotating until it enters the fitting. This way you insure the eccentrics are not clocked slightly different which would cause a shear load on the bolt. With both eccentrics indexed, watch while you torque the bolt because they can spin. You may have to hold the eccentric with a wrench to prevent it from rotating while torquing
Del Lehmann
Mena, Arkansas
Mena, Arkansas
Re: Wing attach bolts
When I had my airplane in Del "wingnut" Lehman's shop in Mena a few months ago, he noticed my aft spar-attach used a "shear nut" PN 374-720 just exactly as the IPC calls for.
That nut was "stripped" and would not torque to the proper specification, so he replaced it with a MS21044N7 (AN365-720 equivalent) which is a full-height tension-nut.
When I pointed out to him that the IPC actually specified the "shear" (low-profile) nut, ... he re-educated me.**
It's so nice to have so many knowlegeable friends on-board here at the forums. (We have several other professional-participants who doubtless also are amused by some of my opinions.) Brad, Jim (c170b53), metalmaster, and many many others...apologies to all I failed to mention.
** Here's the email response regarding my observation from "wingnut":
"It's a misprint. The "A" model shows a tension nut as well as the early 172's and all other 100 series are tension. The shear nut, as we discovered, will not take the torque before it strips the threads. There are several misprints in the IPC's.
..., in this situation the "B" IPC clearly identifies a shear nut, a mechanic who has worked on a few of these should at least question this, especially on a wing bolt. And, although the bolts are in shear load only, because the carrythru fittings "sandwich" the wing spar, it is important to get sufficient compression (tension) to prevent any movement, and prevent eccentrics from vibration induced rotation."
That nut was "stripped" and would not torque to the proper specification, so he replaced it with a MS21044N7 (AN365-720 equivalent) which is a full-height tension-nut.
When I pointed out to him that the IPC actually specified the "shear" (low-profile) nut, ... he re-educated me.**
It's so nice to have so many knowlegeable friends on-board here at the forums. (We have several other professional-participants who doubtless also are amused by some of my opinions.) Brad, Jim (c170b53), metalmaster, and many many others...apologies to all I failed to mention.
** Here's the email response regarding my observation from "wingnut":
"It's a misprint. The "A" model shows a tension nut as well as the early 172's and all other 100 series are tension. The shear nut, as we discovered, will not take the torque before it strips the threads. There are several misprints in the IPC's.
..., in this situation the "B" IPC clearly identifies a shear nut, a mechanic who has worked on a few of these should at least question this, especially on a wing bolt. And, although the bolts are in shear load only, because the carrythru fittings "sandwich" the wing spar, it is important to get sufficient compression (tension) to prevent any movement, and prevent eccentrics from vibration induced rotation."
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
- Bruce Fenstermacher
- Posts: 10320
- Joined: Tue Apr 23, 2002 11:24 am
Re: Wing attach bolts
It doesn't take a professional to be amused. .... .....gahorn wrote:We have several other professional-participants who doubtless also are amused by some of my opinions.) Brad, Jim (c170b53), metalmaster, and many many others...apologies to all I failed to mention.
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Re: Wing attach bolts
Touche'N9149A wrote:It doesn't take a professional to be amused. .... .....gahorn wrote:We have several other professional-participants who doubtless also are amused by some of my opinions.) Brad, Jim (c170b53), metalmaster, and many many others...apologies to all I failed to mention.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.