VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 08-25-2013, 08:08 PM
tkatc's Avatar
tkatc tkatc is offline
 
Join Date: Nov 2007
Location: NJ
Posts: 1,747
Default Landing gear alignment?

Anyone have a good write up of how they did the landing gear alignment? I'm using the grove airfoil gear so it is slightly different than Van's stock gear but very similar. I've searched here and google along with the usual sites but haven't stumbled upon one that fills in all the blanks. "Alignment for dummies".

I have 2 pieces of 8' angle from Home Depot waiting to be put to good use. I plan to clamp them to the gear and start measuring from different points but I DO NOT want to screw up this very critical step. I have zero tailwheel time as it is...the last thing I need is misaligned gear.

I assume I'm only aligning 2 planes:
1. They must be parallel so the wheels are aligned to each other
2. They must also be aligned with the centerline of the fuse.

Do I have that right? Parallel to each other seems easy enough...but parallel to the fuse raises more questions than answers. I've been thinking about running a laser line down the belly of the inverted fuse and take measurements from that...
__________________
My ATC opinion is NOT an official FAA recognized opinion, so any advice you get from me is ONLY my opinion.

Track my RV7A!!

Bought my flying -7A
Building an -8! (Fuse)

Last edited by tkatc : 08-25-2013 at 09:01 PM.
Reply With Quote
  #2  
Old 08-25-2013, 08:48 PM
mannanj's Avatar
mannanj mannanj is offline
 
Join Date: Jan 2005
Location: Mtns of N.E. Georgia
Posts: 1,322
Default

Quote:
Originally Posted by tkatc View Post

I assume I'm only aligning 2 planes:
1. They must be parallel so the wheels are aligned to each other
2. They must also be aligned with the centerline of the fuse.

Do I have that right? Parallel to each other skins easy enough...but parallel to the fuse raises more questions than answers. I've been thinking about running a laser line down the belly of the inverted fuse and take measurements from that...
Tony:

1. Yes
2. Yes

The 8 wheel allignment is done in the final stages with tapered shims on the axle.

I measured my center line with plumb bobs dropped to the floor from the firewall and the rearmost bulkhead. I then drew an extended center line on the floor and measured from the center line outward to the fore and aft points of the angles that were clamped to the flat part of the gear legs where the axles attatch. You can use plumb bobs for this if your fuselage is upside down. You can get by with two plumb bobs. You probably could get by with only one.

You also want to get the ends of the gear legs the same distance fore and aft by measuring from the same point on the end of each gear leg to a center point somewhere on the tail, making sure both left and right measurements are the same.

Hope this makes sense!
__________________
LAUS DEO
Mannan J.Thomason, MSGT. USAF (RET)
VAF788
"Bucket List" checkoff in progress!

Last edited by mannanj : 08-26-2013 at 08:05 AM. Reason: Better explanation. (I hope!)
Reply With Quote
  #3  
Old 08-25-2013, 09:56 PM
Bob Ellis's Avatar
Bob Ellis Bob Ellis is offline
 
Join Date: Jul 2007
Location: Pembrokeshire, UK
Posts: 224
Default

Hi Tony

I made a guide with the link at this log entry - hope it helps - flying 15 months with no obvious gear alignment issues.

Agree that final alignment is done with shims - see here
__________________
Bob Ellis
www.rv-8.co.uk
G-JBTR Having a ball flying this wonderful machine
Donation July 2016
Reply With Quote
  #4  
Old 08-26-2013, 07:21 AM
BonitaRV8 BonitaRV8 is offline
 
Join Date: Feb 2012
Location: Bonita, Ca
Posts: 57
Default Good timing

Good timing on this thread, I just put my main gear legs on yesterday afternoon. Following the instructions I have the inboard U-804 brackets wear plates and gear legs mounted with the 7/16? bolts and the outboard mounts located per the print. I only had one plumb bob so I wrapped it up and had a beer while I pondered the best way to proceed. I?m going to pick up a few more plum bobs tonight and I have Black & Decker laser line thingy but don?t know if I?ll find a good use for it.
__________________
Empannagee done
Wings 90% done
Received fuselage
Reply With Quote
  #5  
Old 08-26-2013, 03:54 PM
tkatc's Avatar
tkatc tkatc is offline
 
Join Date: Nov 2007
Location: NJ
Posts: 1,747
Default

When you get it figured out...come do mine.
__________________
My ATC opinion is NOT an official FAA recognized opinion, so any advice you get from me is ONLY my opinion.

Track my RV7A!!

Bought my flying -7A
Building an -8! (Fuse)
Reply With Quote
  #6  
Old 08-26-2013, 09:26 PM
David-aviator David-aviator is offline
 
Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
Default

Tony,

I never did understand Vans 4 string method in the plan narrative. I called and said I did not "get it", how about if I use a 3 string method? After explaining what I intended to do, the guy said that should work.

Here's how I did it.

1. Set a string over the inverted fuselage running fore to aft exactly over the center line of the machine. The string should be about the same height as the gear legs. This can be done by dropping a plumb bob to a center point at each end of the fuselage and adjusting the string on a rod or some other device that will permit moving it to get it over the center line. Attach one end of the string to a spring rather than tying both ends. The spring will keep it tight.

2. Set 2 more strings, one each outside the gear legs exactly parallel to the center line string.

3. Bolt or clamp a 4' straight edge to the outside surface of the gear leg where the wheels will be attached. Adjust the gear leg to get the straight edge parallel between the center string and the string next to it. Its easy to measure the distance from center to the board or from the outside string. Clamp the gear leg in position for a final drill when it is parallel to the strings. This could be done with just the center line string but it is easier to get the gear legs adjusted using 3 strings.

This, in theory, will give you zero toe in-out with no weight on the gear. Final toe in or toe out can be accomplished later with shims if necessary. There is no way of knowing before hand how much weight on the gear will affect toe in/out.
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
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 09:40 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.