Working on Chapter 13 - Step 10
updated: 25/11/2010
Step 3
– Installing the Worm Drive Assembly
I will be using Jack Wilhelmson's Electric Nose Lift instead of the plans method for extending & retracting the front nose wheel. Whilst going through the Parts ordered from Wicks and the metals parts received from CG Products for Chapter 13, I noticed that I had some how missed ordering the MKNG-4 internal bracket, which is required when fitting MKNG-3 onto the strut, as well as the 2 x NG-14 spacers. These aren’t currently listed as available from CG Products, so I checked with Aircraft Spruce and they confirmed that they had them in Stock. I thought about making them myself, but there is not enough information provided in the plans on material spec’s and dimensions. The NG-3A bracket and MKNG-6A bearing were supplied from Jack when I ordered the electric nose lift.
I started first with making the NG-5 mounting plate and left drilling the 4 holes until the final fitting, to ensure that the holes lined up OK. As I hadn’t yet received the 2 x NG-14 Spacers I ordered from Aircraft Spruce, I couldn’t completely assemble the two NG-30 panels, so I cut a couple wooden spacers about 3” wide, which were then clamped in between the NG-30 side pieces. Each wooden spacer had a centre line drawn on it, which was aligned with a corresponding centre line on the NG1-L strut. This ensured that the strut was nicely centred between the NG-30 panels, before the enhanced roller bearing MKNG-6A was permanently floxed onto the NG1-L strut. After cure the strut along with the MKNG-6A bearing was removed from the NG-30 side panels, setup on the pedestal drill press and the 4 pre-drilled holes in MKNG-6A redrilled along with NG-5 as per plans. The NG-5 plate was then installed with flox and 4 x MS24694-S70 screws and MS21042-3 nuts. I found that all 4 MS24694-S70 screws were too short and I couldn't get the nuts to tighten enough, so that a the threads protruded past the end of the nut. I ended up removing all 4 screws and replaced them with the longer MS24694-S74 screws.
I then moved onto mounting the MKNG-3 & MKNG-4 Brackets onto the NG1-L Strut as per plans, centred 6.71" from the centre of MKNG-6. At this point I jumped around a little and moved onto completing Step 4, which sees you install the box assembly (NG30) onto the fuselage, I also decided to install the nose floor sections covered in step 5, but stopped at fitting the sides as I worried that I would not be able to easily match drill the 2 remaining 1/4" holes, that must be drilled through the NG30 panel hard points and nose lift mounting brackets. The exact position for these 2 holes need to be determined and after a bit of web surfing, I followed the method described on Bernard Siu's Website. To follow his method I had to temporally fit the Nose wheel fork assembly (MKNG16 & MKNG15) onto the NG1-l strut, by drilling 4 holes through the stainless steel Support foot and clamping the assembly into place, without the required Flox. Not sure yet if the fork needs to be removed later on to cut the strut door in the bottom of the fuselage?
The principle is based on the fact that the front nose wheel axle centre line is located at FS16 (as stated on the back cover of the Plans) and we already know the location of FS22. So the electric Nose lift is bolted into position and the actuator is extended until the limit switch stops. The actuator and mounting brackets are then moved, pivoting on the front bolt, until the front axle centre-line lined up with FS16. The location for the two 1/4" holes were slightly forward of my hard points, by about 1/8", but fortunately still within the hard points. If I did this again I would recommend making the hard points a little bigger or elongated. Before drilling a small pilot hole through the hard point and marking the location of the 1/4" hole on the bracket, I shined a torch from inside NG30 to make sure that the new 1/4" holes would not be too close to the edge of the mounting brackets. The brackets were then removed, clamped together and drilled on the drill press, reinstalled and the holes in the hard points drilled to match the brackets with a long 1/4" drill bit.
The next step to complete the installation of the Electric Nose lift was to cut a 1" slot at 22º, through the F22 bulkhead, for the manual extension rod. Jack Wilhelmson's method described in the install instructions, which were supplied with the nose lift, require the nose lift to be removed and the use of a wooden template to project a reference point onto the face of the F22 bulkhead. I decided to again follow Bernard's method here and used a laser to determine the initial reference point, the location and drilling of the holes for the slot were then cut as per Jack's procedure. I decided not to drill and locate the manual extension rod through the Instrument panel at this stage, but to wait until after I had completed the panel lay-out for the instruments.