Quick questions for those who've completed SB

[yankee-flyer]

Gotta start next week on the SB mods and have a couple of quick questions.

1) can the mods be done as two separate steps-- i.e, do the fuselage doublers with the airplane on the gear, and then do the gear one side at a time with the wings on. I normally jack up one wheel, support the wing and fuselage, and pull the wheel. Replace it and do the other side. Seems like this should work for the gear mod but?????

2) Is it possible to match drill the doublers with the tank in place-- I'm thinking slide a piece of plywood or thicker aluminum between the skin and the tank? Haven't checked clearance.

3) I know I need to order the countersink but I've seen mention of a "special" 1/4" bit. Do I need one of the long 12" bits?

THANKS!!!!

Wayne 129241/143WM

 

[JBPILOT]

Hey Wayne - -

I did mine one side at a time. I pulled the wing, and did all, then the other side. I would pull the tank. One mistake, and you might have a really big problem.

John Bender

 

[Mark Henderson]

I guess you could do it that way, but jacking the plane using saw horses is so easy. Vans has the dimesions in the MM, and Tony T has photos and dimensions on his web page. I've done the one wheel lift at a time, and in my opinion it is more work than putting the plane on stands. The stands cost less than $20 to build.

 

[Geico266]

I guess you could do it that way, but jacking the plane using saw horses is so easy. Vans has the dimesions in the MM, and Tony T has photos and dimensions on his web page. I've done the one wheel lift at a time, and in my opinion it is more work than putting the plane on stands. The stands cost less than $20 to build.

Home depot has saw horses for $20 that are very close. Cut the legs off about 3" and it is perfect.

 

[engineerofsorts]

Special countersink???

Gotta start next week on the SB mods and have a couple of quick questions.



3) I know I need to order the countersink but I've seen mention of a "special" 1/4" bit. Do I need one of the long 12" bits?

THANKS!!!!

Wayne 129241/143WM

The detailed destructions describe how to countersink with a bit that doesn't have the 1/4 " pilot, clamping things down securely on a drill press This works as long as the countersink's total widh is wide enough--1/2" I believe. That was in my collection of bits included in my Avery countersink kit. It worked just fine for me.

 

[WingedFrog]

Gotta start next week on the SB mods and have a couple of quick questions.

3) I know I need to order the countersink but I've seen mention of a "special" 1/4" bit. Do I need one of the long 12" bits?

THANKS!!!!

Wayne 129241/143WM

Oddly enough, in the list of tools VANs listed in the "destructions", the 12" long #30 bit needed to drill the additional 2X2 holes through the center channel but they did not mention the need of a 12" long 1/4" drill bit to drill these same holes to the final diameter.

 

[txaviator]

Gotta start next week on the SB mods and have a couple of quick questions........
3) I know I need to order the countersink but I've seen mention of a "special" 1/4" bit. Do I need one of the long 12" bits?

THANKS!!!!

Wayne 129241/143WM

Wayne,
As Rob said, you do NOT have to have a special countersink bit - with regard to the pilot of the countersink bit. However, make certain you use one that is whatever degree the SB calls for. I don't have the plans in front of me for the exact degree. And just follow the SB notes exactly: countersink the holes to a 1/2" diameter (1/2" O.D. measurement on the top surface of the plates). Be sure to clamp them down in a drill press as depicted in the instructions and you'll have no problem. If you don't own a drill press, I'd bet you could take the plates, the countersink bit, and the instructions to any local machine shop. It wouldn't take them one-two minutes to perform the work...but the "clamped down to a drill press" part of the instructions is critical for a centered hole.

I did find it very useful to have a long #30 bit (12") when drilling the front jig holes through the U-Channel.

I can't help any further though, since I wasn't already 'on the gear', but am now. And my tank wasn't installed, but I'd be REAL scared to be working right up against it installed.

 

[rvbuilder2002]

Oddly enough, in the list of tools VANs listed in the "destructions", the 12" long #30 bit needed to drill the additional 2X2 holes through the center channel but they did not mention the need of a 12" long 1/4" drill bit to drill these same holes to the final diameter.

I think that is because the only places the S.B. specifies the use of the 12" #30 bit is to remove the rivets holding the F-1204T-L & -R Skin Stiffeners to the F-1204 Center Section Assembly, and match drilling new holes in the new F-1204U-L & R.

Standard drill bits can be used for all other hole drilling.

 

[WingedFrog]

I think that is because the only places the S.B. specifies the use of the 12" #30 bit is to remove the rivets holding the F-1204T-L & -R Skin Stiffeners to the F-1204 Center Section Assembly, and match drilling new holes in the new F-1204U-L & R.

Standard drill bits can be used for all other hole drilling.

Thanks Scott, I was under the impression that the vertical part of the U channel required a longer drill bit to drill throught the F1204V drill guide. I have so far only done the skin part of the sb, the LG part having been delayed during painting.

 

[DHeal]

I just completed the SB on my "still-a'-building" RV-12. Not a difficult project since the airframe is sitting in my shop. I drilled the outer "template wing" holes from the bottom up -- seemed that access and alignment were easier that way. I drilled the inner "template wing" holes from above per the SB and found that a 6" long jobber's drill fit the area the best (12" was too long and < 6" was too short).

 

[vette_guy]

Washer size shown on gear/fuselage SB

Why are small washers used for the attaching bolts? Where possible, a larger washer would displace the pressure over a larger area in the u-channel.

 

[engineerofsorts]

an engineer-out-of-his-field response

Why are small washers used for the attaching bolts? Where possible, a larger washer would displace the pressure over a larger area in the u-channel.

Being a sparky (Electrical Engineer) as opposed to a metal bender (mechanical engineer), I may be out of line here, but I suspect, if you look at the placement of the bolt, it is in a spot machined out of the side of the u-channel. A larger washer would not fit in there, and, to accommodate a larger washer would require milling out a larger chunk of the u channel side, which may be undesirable for overall structural strength.

 

[rgmwa]

NAS1149FO532 Washers?

In Fig 17 and also in the diagram on page 31 showing the outboard attach bracket assembly, 2 NAS1149F0532 (thin) washers are required, presumably under the bolt head, although it doesn't so so.
However they are not listed in the inventory on page 2 and were not included in the hardware (unless I lost them). I've ordered some, but don't recall seeing any comments in any of the posts. Have I missed something?