In a posting on 28/10/2001, Graham Singleton described how to avoid having to crawl into the fuselage rear compartment in order to carry out some of the build procedure. The posting is reproduced below together with pictures supplied by Graham. Graham is at graham@gflight.f9.co.uk . Further comments by Paul Stewart appear next, followed by a contribution by Ferg Kyle and then pictures of my own aircraft.
Tony K describes in his excellent web site the highly uncomfortable journey into the rear fuselage to install the pitch stop.There is a way to avoid the crawl in the back. Too late for you now of course but not for some.
On a couple of the Classics I have helped with we took a splash from the fuselage top, then temporarily bonded it to the top of the pitch rod containment bulkhead. This was done by taping the splash into its correct position in the upper fuselage, putting blobs of 5 minute on the bulkhead then assembling to two fuselage mouldings with clecos until the 5 minute epoxy set. The lower fuselage was restrained in its cradle of course. Now we were able to take the fuselage top off leaving the splash in place on the bulkhead.
We made the attachment brackets, described in chapter 21, p 5 of my manual, in comfort with no difficulties like lying on our backs in the tail cone. We also fitted the upper and lower pitch stops at this time using a U shaped moulding bolted to the sides of the bulkhead.
Another bonus here was that we could get the pitch control adjustment set up accurately before bonding on the top.
When the fuselage top was finally bonded on Redux was applied to the top surface of the splash to bond with the inner skin of the fuselage. A very awkward job made relatively easy and more accurate.
We also used the same technique to make the rear bulkhead upper flange, another job requiring great dexterity at arms length in a very confined space.
Paul Stewart (#432, <paul-d.stewart@virgin.net>), who is the builder of the aircraft pictured on this page, has added the following extra comments and a further picture.
The top is not yet as advertised bonded on, although I don't forsee any problems. Many will have spoted that this is an XS and not as described a Classic. Positioning where to take the spash moulding from the fin is tricky,as tiny movements fore and aft in such a highly raked fin make a large difference in height - make sure you have the upper canoe clecoed in position before positioning the splach moulding on the bulkhed. But having done so you have the great advantage that the bulkhead is secured to the fin fore and aft rather than just aft if you try to do it 'in situ'. For both splash mouldings I merely lined the upper fuselage with cling film as a release agent The upper and lower stops for the elevator counter balance weights are 4 plies of BID with rubber stops formed from sections of auto fan belt reduxed and riveted onto the inside.
The push rod containment bulkhead is completely removable. Having made the splash moulding I positioned it on top of the bulkhead with a few blobs of rapid (with the upper canoe clecoed in position). After the rapid was set, remove the upper canoe leaving the spash in the perfect position on top the bulkhead. I then layed up brackets of BID from under side of the splash moulding to outside of the bulkhead. There was a piece of cling film between the bracket and the bulkhead but normal scuff sanding on the under side of the splash moulding. When all was cured, I drilled the bracket and bulkhead to take two of those -3 cross headed screws(can't remember the part no), a large area washer and MS21042-3 nut. Once that was all done I cracked the brackets away fom the cling film lined bulkhead and cut through the blobs of rapid. I now have a completely removable bulkhead. Below is a picture of the end result.
Ferg Kyle has evolved his own variant of the technique, which he describes below.
In the upper sketch, the containment tower sides are shown in brown. In the lower sketch, they are shown uncoloured, but the front corner parts are in brown. The thin green covering is meant to delineate the BiD skin on them.The sketches show the arc of the nascent fin in the fuselage skin, and the dashed angled line in the lower sketch is meant to show where that becomes the curved fuselage top again.
Basically, in copying Paul Stewart’s creative design [ specifically per his scheme to avoid crawling into the black depths to administer BiD flanges] and John Cliff’s version to make the tower removable [so as to get aft of the tower easily if need be], I have shown my minor copy as a guide only. It has been passed by local inspection for my area, but will require OK in yours perhaps. I take no responsibility for acceptance or use of this.
The device allows removal of the top of the tower to get past it (unbolting), but permits attachment of the fuselage top with Araldite 420 adhesive at the time the top is attached to the ‘canoe’.
It was achieved thus:
[1] The tower was created per the manual and installed at the bottom;
[2] The top is offered down onto the ‘canoe’ with a bright light facing upward in between the tower sides such that a shadow of the tower tops is cast and marked on the skin above;
[3] The top is removed and inverted, so that the positions in [2] above are transferred onto the inner skin;
[4] Onto a release film, a 5-ply BiD (+/-45deg) - the “flange” - about 8” wide and 6” long is centred about the tower marks (see sketch);
[5] When cured, it is trimmed to size and temporarily fixed to the fuselage top - Hot glue;
[6] A piece of 3mm plywood is cut to fit between the tower sides at the top;
[7] The tower tops are covered with release material, all sides, down to about 3” from the top;
[8] A 5ply BiD about 5-1/2” by 3+” is centred over the plywood, and placed between/above the tower tops per the sketch, such that the wood is between the tops and the BiD drapes down the outside;
[9] Add an application of flox per the sketch (between span and flange inside and out )- fix and cure;
[10] Free the ‘span’ Bid and wood in [8] above, trim to size and remove release material;
[11] Apply the span bracket to the tower top and mark and drill for four -3 (#10) bolts;
-- you now have a flange which matches the ceiling, and a wood-enforced span bracket which fits the tower top. The next job is to marry the two so that the fuselage top will fall into place when 420 adhesive is applied - much like the bulkhead flanges;
[11] Re-lower the fuselage top, ensuring that the flange and span bracket are centred as specified - (I drilled a centring hole for final fixing of fuselage top);
[12] Reach into the chasm from the rear maintenance hatch and remotely apply 2min epoxy to the juncture of flange and span bracket to affix one to the other;
[13] Crack the hotglue above the flange to release it and lift the top free of the flange;
[14] Remove attached flange and span bracket and apply 5ply BiD flanges to fix both together;
[15] Bolt cured fixture to tower top and the flange is ready for the top to be applied with 420.
All of this so I don’t have to squeeze into the cavern and ache for a month. Of course the correct amount of 420 needs to be applied on the day…………..
Now some pictures of the same :-
(600x450, 39K)
This shows the way I marked the fuselage roof with the exact site of the tower corners. The lamp provides the shadow of the exact position which I mark on the outside then extract the fuselage top, invert and shine a lamp from below to transfer the position to the inner roof.
(600x450, 42K)
(600x450, 43K)
(600x450, 49K)
Ferg is at mailto:VE3LVO@rac.ca
I (John Cliff) have now put the top on my own fuselage using basically the method described above. It is a Classic, so the rear fuselage looks different.
First, the upper pitch stop was fabricated across the top of pitch rod containment structure, generally as described in the manual and set to 4.4 degrees. Then the top of the structure was cut off and reattached with bolts to make it removable (or rather to make the rest of the structure removable when the top is bonded to the airframe, so allow freedom for the structure to tilt and drop away from the top if it ever has to come out). One of the layups was done first and four of the bolts fitted, so the top could be relocated accurately. This stage is shown here. Three bolts were used each side, for rigidity, though one is an AN525... part as I found a normal bolt plus washer fouled the large balance weight.
The mouldings were then made inside the fuselage top, as Graham describes - being a Classic the rear one was easier to locate - and the top put on with the mouldings attached with self-tappers to flox them to the pitch structure and rear bulkhead..
The reinforcement layups (pitch structure top to newly attached moulding and upper rear bulkhead to newly attached moulding) were then easy to do, before putting the fuselage top on - not forgetting to put some redux on the tops of the new mouldings first.
It worked well for me and I can recommend it. [I'm sure the method described in the manual is less work, but it is the kind of work I wished to avoid.]
Problems with or comments on these pages please to John Cliff (john@crixbinfield.freeserve.co.uk) 23/10/03