Canopy Actuator - Part 3

The rear handle was mounted onto M6 high tensile hex head screw. A single AN4 washer is fitted with the bolt treated at the base with Loctite 263 then assembled. The external rear unlocking handle will not be installed on this aircraft. 

The front handle requires a short length off M6 all thread rod supplied to accommodate the internal and external handles. The rod was fixed into the external handle with Loctite 263 creating a specialized bolt that is then fitted into the actuator bar with Loctite 242 thread lock to allow normal removal with the internal handle is fitted at the other end

The bolt and threaded rod engage's for full depth off the tapped hole's of the handles to provide maximum support for the aluminum handles.

Revised fixing for Actuator bar

The nylon guides for the actuator guides are fixed using M4 stainless steel screws. These are threaded for their full length, a bit of a no-no any load bearing device. As no bolt under 3/16'' can be regarded as structural [say my old design books] it's OK but it was to much for this builder to bear - it had to be correct so he could feel better. 

Modification: A decision was made to enlarge the mounting to 4.8 mm [3/16''] and install AN3 bolts with AN970 washers to back up the factory nylon washers at both locks [4 places]. The downside is the amount of wear allowance is reduced by 0.4 mm [0.016''] but this was considered an acceptable compromise. 

This is a unapproved modification: Refer Disclaimer

Center Guide
The center guide has to be fixed with a M4 x 25 mm counter sunk screw. This is required as it's will foul with the mounting off the roll bar. The side frame and the nylon guide were countersunk to ensure that the head was flush. 

The side cover's for the actuator and the matching assembly on the other side cannot be fitted until the roll bar is installed. Three [3] AN3 floating nuts installed on both sides allowing removal for heavy maintenance. This installation required a packer to be installed at both sides.

Rear Spring Stop
More binding was noted again and it was found that the tab that the spring is mounted on had a slight bend. This was straightened but there was still a bind so the bracket was removed and the slot opened to 5 mm with a chain file then lengthen to remove the binding at the base.  It would be better to fixed with a couple of clecos until ready to close.

Cockpit Painting - Part 1

The air frame is supplied by Flying Legend is fully alodined but the cockpit area need's painting and as this is a military themed cockpit it leaves a basic pallet of grey and black.

One of my past associates in crime Laurie Georgeson painted his Barracuda cockpit upper frame in grey undercoat - sanded it and then sprayed it with automotive acrylic clear. The results were spectacular and everyone was stunned how effective and simple the finished product was to create but you have to like light grey. 

This had led to the decision try the same scheme with the Tucano cockpit by spraying etch primer and clear coat when finished. Experience has taught that in highly profiled and confined area's like cockpits, spray cans can more efficient than using a high pressure spray gun. This is a result of the lack of bounce back and resultant rough finish from not controlling over spray settling back on the job. 

As luck will have it, Wattyl Super Etch is available in spray cans in both the colours - problem solved.

Note: For those seeking a smoother finish immerse the can in boiling water to preheat and then spray - the higher pressure gives a finer finish. Do not mix the can after pre-heating. This is not required for the etch but can help with the much thicker clear.

The cockpit interior is now primed and when the time is right will be prepared with a Scotch-Brite scourer pad and Prepsol, touched up and coated with clear to seal the exposed surfaces. The etch has proved very forgiving with application and except for the most ham fist-ted spraying, dries to smooth finish quickly and is at full strength after 24 hours. Where runs do occur they are easily removed with a light sand with aluminium open cut paper. This is very important as it is impossible to tidy up serious paint runs in an area with few flat surfaces.

The application of the clear was best done by allowing the etch coat to dry for 24 hours,  then apply a light "dust" coat twice before applying wet coats to achieve the desired gloss. The test application on the joysticks have proved this to be the best approach. 

The clear will be applied when all the major accessory and associated mounts are manufactured. Once done they can be then refitted and all the necessary mechanical and electrical connections commenced. When is that point - that is the $64 question but its not to far away.

The black will be applied to the floor panels and the top side of the longeron rail to match the RAF Tucano with there may be a little RS War Birds influence as well. This combination should give a small visual lift to the cockpit area as most of the accessory's and equipment will also be black.

Is this perfect - no but for this builder achievable and that is what's needed.

Wattyl Super Etch Specification: Click Here

Joystick Assembly - Part 2

Fit the first push rod and front joystick - refer factory drawings. The connection for the pivot was made using a drilled AN4 bolt and castellated nut due to a remote chance of relative movement between the bolt shank and the mount. 

Pilot Joy Stick

Next insert the assembly through the hole provided in the No 3 bulkhead. Once in position install AN3 bolts with nylock nuts - do not tighten

Install the collar through the hole provided for the middle bearing in the main spar - slide onto the tube for its full length. A little WD40 helps the sleeve slide onto the tube.

Install the middle assembly - the joy stick was added latter. Insert it onto the front bay JUST enough to allow the front thrust ring to be installed, then slide the elevator rod into the opening. The pilot joy stick will have to be full aft during this operation.

Middle & Rear Assembly fitted
[Note: Pump is a trial fit to examine possible brackets and location] 

Inserting Elevator Rod - Note: Thrust Ring
Note: Grease on face of thrust washer

Rear Assembly

The bolt securing the elevator tube has to be disconnected to allow installation of the end assembly. Fit bearing assembly and slide to the welded lug. Fit sleeve and slide fully onto the end assembly tube - maneuver past middle assemble to engage bearing into rear spar.

Note: The assembly was painted, this prevented the bearing and sleeve sliding freely and had to be linished.

Assembly

Begin at the front by installing the stiffeners provided - tighten to allow installation of the stiffeners then back bolts off - repeat at the middle spar.

The bracket provided for this kit were originally intended to be installed at the rear spar but have been relocated the the main spar as shown. The builder chose to reshape to match the front assembly,

Front Stiffener

Rear Stiffener

It is critical the screws are install into the holes that the factory tapped.

All bolts must be loose for this task. Slide the middle assembly forward and then engage the coupling provided. Re-establish the correct position and then hand install each M5 screw.

 DO NOT FORCE

If the first one will not engage correctly rotate the assembly with the marks aligned and try another. If you have to use Allen key do so only when required and only after trying all the others - if none will engage by hand recheck the alignment.

Repeat at the rear assembly.  

At this point lightly nip all the bolts and check freedom of operation and if any binds exist locate and rectify.

Install the last elevator rod fitted with rod ends through the back of the rear assembly then refit the elevator tube.

Note: The screws supplied for the couplings are stainless steel and the instructions called for drilling the heads. This proved to be impractical and they were replaced with M5 Unbrako screws to allow the heads to be drilled as instructed in the plans.

All the working faces of the bearings are polished with 400 grit wet & dry paper by hand linishing. The bearings used are a glacier bearing and in theory require no lubrication but it was found that the application of grease at all working faces greatly reduced stick drag.

Co-Pilot Joystick
The two elevator push rods are connected at the same point as the co-pilot joystick. This was achieved by laying the assembly as far on its side as practical and using a small bar inserting the rear rod end into the clevis. A surplus AN3 bolt was used to capture both assembles then the correct AN4 bolt pushed thought to engage the assembly. The bolt was fitted with a light washer at the head, full washer and AN4 shear nut. 

The rod end of the co-pilot joystick should be adjusted to the same center distance as the pilot stock for assembly - repeat the technique outline above. The stick can be rotated in the housing for adjustment as required. Assembly joy stick to factory drawings - see photo front assembly

The elevator rods were painted red for high contrast at inspection

Re install stock stops in the tapped holes provided front and rear. Recheck assembly for freedom of movement.

Footnote: If any items are dropped into the tube during assembly they MUST be removed regardless of the effort required - failure to so may jam the assembly in operation due to the tight clearances.

Joystick Assembly - Part 1

Start by identifying all the components shown in the factory drawings. The joystick itself is supplied assembled joined by two [2] aluminium sleeves fixed using three [3] M5 x 10 cap head screws.

Before dis-assembly it is critical that the correct relationship of the sleeves in their current position be maintained. The sleeves have been machined with the three [3] machine derived BUT the each hole has been tapped through the steel tube making each one unique. Tapping in this manner ensures that there will be full bearing on the screw threads and effectively locking the completed assembly into one solid unit. Pop mark near the top screws using a auto center punch to produce dimples unique to both sides. Place the same unique pattern onto a mating face of the passenger joystick mount.

Remove all M5 screws and place to one side and slide sleeves off tube to break the assembly into its three parts.

On this builder aircraft the following work was undertaken on the parts supplied.

1. Dress inside face of clevis where rod ends mount - check before assembly as if they are tight this cannot be done in situate
2. Check the length of the rear joy stick from the pivot to the rode center-line matches the front unit when assembled
3. Cut slot to allow to allow cables from the selected handle to exit the joystick. The design precludes exit through the base
4. Ream both holes in clevis to 0.25'' [1/4'']

The slot location was opened up with a step drill to suit the 10 mm loom tube then joined using a Dremel Metal Cutting disc and the opening is dressed using flat files. Polish opening to remove any sharp edges and trial fit loom tube.

Thrust Assembly

The assembly has to have a fixed location in the aircraft and to do this a series of thrust ring's and packer washers are supplied.

Thrust washer location

The drawings shown this location at the rear of the passenger joystick and is to be located between the rear thrust washer and the face of the rear coupling bush. On this builders kit the thick spacer washer have been punched and were a tight fit and would have required dressing to allow them to slide on the steel tube.

This lead this builder to re-examine the task. If the rear spacer washer is relocated to the gap between the front sleeve and the face of the mounting bush with the same result achieved in a more precise manner. 

Revised Thrust Assembly

The weld edge on the tube was lightly dressed with a file and the spacer washer trial fitted - once satisfied with the fit it was installed with Loctite 263 and allowed to cure. The gap between the two items was measured and the loose thrust washer machined to suit - overall width [measured] minus 0.5 mm nom. to allow float. Dress the face of the bearing to remove any paint that was applied when primed.

This is an unapproved modification refer disclaimer.

Final Assembly

Disassemble - linish steel face using 400 wet & dry in the area of the bearing then clean. Using a suitable grease lightly coat the bearing face and the working faces the aluminium thrust washer's. Check for free operation. If all is working correctly assembly can commence.

Bench Folder

These are available very cheaply every where but Australia but this builder decided based on previous experience that one was required - I gritted the teeth and paid the bill.  

A modification that must be undertaken is to modify one of the the sharp folding edge's to a radius. The aluminium used in construction of aircraft will NOT fold through a sharp edge to 90 degrees without cracking. The radius is easily created using files, begin by filing a 45 degree chamfer 2 mm wide across the full length, then chamfer the sharp edges and finally blend into a radius using a rolling action and draw filing. Finish with 240 grit emery strip by lapping across the full length blending all the edges together.This radius will be good to about 0.6 mm [0.025''].

This tool can also act as a poor mans gillo when combined with a Ofla Knife. With the un-radiused edge of the clamping bar placed along the cutting line and clamped to the frame it frees the operator to use two hand to cut thicker sheet up to 1 mm [0.040'']

Clamping bar acting as cutting guide

After cutting through about 50% fold and break free

Cutting smaller opening - be carefully to stay withing cutting area as the Ofla knife
scribes quite deeply with each cut

These tools have proved invaluable in fabrication of side panels and brackets to mount hardware.

Wiring Fuselage - Part 1

This builder has decided that its a now the time to rough in the cables to the rear of the aircraft. Electrical control should be seen as an integrated part of the construction, not a job to be undertaken when construction is completed and when access to the relevant area's of the aircraft is at its worst.

          Key areas identified to be installed at this stage:

• Trim Power and Indicator 
• Red Beacon 
• Whitetail light 
• Flap Power 
• Flap Controller 
• Flap position Indicator
• Hydraulic Pump power
• 
  

As part of the Flying Legend documentation for the aircraft a basic wiring diagram is supplied in the pilot's notes but like all diagrams is for only one plane - the one that it was built for, and every experimental aircraft is a real individual. 

To begin the installation of the hardware and wire, it is critical that you have a firm idea of how the aircraft is to be operated and the selection of equipment required to meet the specification and a scale drawing of the panel. The internet has made this an easier now that most manufacture now has their manuals and equipment diagrams online. From this, a detailed wiring diagram and panel layout can be developed. Refer previous articles on the panel and wiring.

Does this have to be 100% accurate - NOT at this time but it should be as precise as the available information allows, however, the panel layout should be close to final as this has the least flexibility. Cable cores can be reassigned, but hardware is a lot harder to move


Installation:

CAT. NO. HP1225

Now there is all that information there is a need to translate the idea's into construction. One of the first decision faced is where to place the cable runs. No drilling of former's should be undertaken unless authorised by the factory and that applies double if it's laminated. Examination of the structure opened up the possibility of installing the cables in the starboard longeron. To provide protection for the wire bundles they are introduced into 10 mm PVC loom tube from JayCar Electronics.

At this time this builder is examining drilling a hole through the firewall to intersect with the longeron allowing cables from the engine compartment to enter the aircraft. This will be considered in a future article after a firewall layout is undertaken with particular attention taken to battery location.

Starboard Side

Exit to Fuselage - Notch lower flange to allow smooth exit
of conduit - protect edge with rubber channel

Exit to Flap Controller and Mixer Box - Notch flange to allow cable
to exit - protect edges with rubber channel

Note: Rubber Channel U - Aircraft Spruce Part # 05-0140 - 3/8'' x 1/32''

Canopy Hinge's

Before the side panel on the starboard side can be fixed two tasks have to be undertaken. Both canopy hinges have to be fitted and the interior cover panels have to be matched drilled to the top rail.

Starboard Elevation [hinge side]
Note: 1100 mm refer latest manual

Trail assembled both hinges - One off the hinge sets supplied had a slight misalignment from the factory welding but was corrected using an torch to heat the lug and then pressing the pin into both hinge points to align both lugs using a vice. When cool the pin was removed and a hand reamer run through from both side's.

Note: The side skin must be fitted at this time with clecos. No allowance for the interior skins is required as these are notched to fit around the hinges

Rear Hinge
Top hole drilled first

Front Hinge
Top hole drilled first

Check fit of the hinges as they must be flush with the vertical face of the longeron while flush and parallel to the top side of the longeron. A 0.025'' aluminum packer was fitted at the rear hinge to correct a slight misalignment. 



Once aligned correctly the hinges were then fixed with 4 mm aluminium pop rivets. Only fit the top rivet when removal of the side panels is NO longer required.

Note: There should be no 1/8''pop rivets under the hinge mounting face on the top side of the longeron.

This builder elected to install a pop rivet into the top side of the hinge at the redundant hole. These were drilled 1/8'' and proved useful to hold the hinges in position for drilling described. 

It was not advisable to drill all four holes then pop rivet. Drilled one hole at the top edge and fitted a cleco, checking the alignment before drilling the next hole, then pop rivet both. 

Repeated for the remaining two holes.

Drilling Top Holes:
Draw a line between two rivets ensuring that the line intersect with hole to be reused located under hinge in photo below

Mark edge of hinge as shown and slide hinge back - measure distance from mark to hole center line - in the case below the hinge was move forward slightly to place the new hole on the center-line of the flange

Once you are happy with the location drill a new hole in the hinge flange 1/8'' through - if correct the two will line up holding the hinge in its correct location. 

Note: To ensure greater accuracy the pilot hole was drilled with a center drill BEFORE drilling to final size.

Use a fine line felt tip pen making sure it intersects with the hole center - critical.

DO NOT RIVET THIS HOLE IT IS THE LAST OPERATION AFTER INSTALLATION OF THE INTERIOR SKINS

Pop Rivet Removal

You have to remove a number of temporary factory rivets to commence assembly of various parts of this aircraft. The pop rivets used do not have a full length mandrel and are therefore easily removed using a drill on the center of the rivet to remove the head.

This builder only has access to battery tools which operate at much lower rpm compared to air operated toosl shown in the video below. Their advantage is they are relatively quite and are ready to use on demand. An unstated advantage is that most people that surround us are unlikely to be in love with your compressor running to provide air on demand.

Note:  Set the clutch at it lowest setting to ensure that if there is the slightest increase in load it should release the clutch. Ensure the battery has a good charge to provide maximum revs.

Select a sharp drill that is slightly smaller than the head of the rivet to be removed. Drill to about the point shown and at this point pulse the drill as it is close to breaking the head free. Keep drilling using small pluses until the head breaks free.

Note: For the 3.2 mm rivets a 4.5 mm drill works well

Drill Rivet

Stop & Pulse Drill from here

Head sheared off

Remove the rivet using a small punch to drive out the mandrel or if you have access to the rear of the rivet remove with a pair of side cutters with a rolling action.

Generally this works but this builder found the rivets that secured the skin at the top longeron were another case [location shown above]. After a number of blows of ever increasing force, it was clear the lack of structural rigidity was not allowing the blows to do their work and there was NO rear access.

At this point it was decided to resort to the drill, not the favored option as you can loose control easily.  Punch out the mandrel with a 1.5 mm punch then drilled out the stem using a sharp 2.5 mm drill until it breaks free, generally before reaching its end - little force is required just great care. 

  Removing Pop Rivets

Dimpling Skins

Flush riveting the first 30% of a flight surface can effectively reduce the majority of parasitic drag created by riveting with the remainder of the wing providing little drag reduction for the additional work.

Begin located in Australia C press riveting frames were unavailable and due to cost and size airfreight was not a option. It was decided to examine the use of a low cost option of using a dimple die and pop riveter.

Dimpler - click link 

Aircraft Spruce lists a 120 deg dimpling tool to suit the Cherry G-28 pop riveter. This unit is designed to screw into a Cherry pop riveter tool but as luck would have it did not suit my unit. With no alternative available it was decided to modify the die and the threaded portion was cut off. 

Note: There are other dies available that are universal but this one created the result illustrated

A trial on one rib indicated that the tool created a usable countersink in the rib and the decision was made to proceed to dimple the leading edge of the elevator stab to the face of the spar. If you were planing the next grand champion then it would pay to use better equipment but this is beyond my ambition and skill level. 

Modified Dimpler

The final result is dependent on technique and this builder will describe his method as clearly as is possible below. 

The nails provided have about a 0.25 mm clearance in the pre-drilled hole so the best method is to install the female die at the rear then place the male at the front of the component. 

For ribs use a thumb and forefinger to support the female die and too center the male on the hole. Mount the puller and while holding it about 1/3 along the handle close the two dies to hold the dies in potions and apply light squeeze, next place the other hand at the end of the handle  and apply firm pressure clamping the dies closed.

Update 11/5/16:  A new tool has been found to create a better dimple - Click 

For the skins use the same technique but fit the rivet gun, apply LIGHT pressure and wriggle the male die until it "Clicks" into center off the hole then repeat the technique above.

The nail will require light dressing to remove the ribs created by the tool from time to time - this becomes less with use and this builder used two nails for the elevator stab. When correctly centered there is a very short stroke required to form the dimple. The factory supplied rivets fitted neatly into the assembled countersinks.

Footnote: The blue painters tape covers the holes that fix the skin to the spar. They are in place to prevent the builder accidentally applying a dimple to any of these holes as time passes working and the builder enters a derrrrrrr..!!!! zone. Knowing this a series of NO RIVET was also added with a felt tip pen. A story for a future blog will illustrate how errors are created by human performance during assembly.

Completed Elevator Stab

Stab fitted into the Assembly Jig

Comment - 21/6/18
I purchased a CherryMax riveter to fit the die as it was easier and helped when the nail broke as the two components just took off - Tried another similar product from another supplier and this one produces the best dimple.

Nut Plates

As part of the assembly the spars of the aircraft tail require nut plates allowing installation and removal of various components without access to a nut. This task is was accomplished using simple jigs and micro stop countersink.

Drilling Nut-plates
Using a piece of dressed timber, drill a 5 mm hole through then using a #8 screw  of sufficient length to engage the plate. Insert the screw through the hole and then fit a nut plates supplied with the kit and drill a 1.5 mm hold through one of the lug mounting holes. Insert a a discarded pop rivet shaft as a locating pin as it adsorbs the torque of drilling and its a true finger saver.  

Drill the hole on the opposite side to the pin 3.2 mm [1/8''] through, remove and refit the nut-plate and drill the other side and de-burr. 

Now all that you do now is the rest - Joy..!

Drilling Spars Nut Plates
While some of the spars in this kit had the mounting holes for the rivets to fix the plates drill they were not on the elevator stab spar but all require countersinking. Locate a #10 bolt or screw and fit into a unmodified nut-pate to a depth to secure the two items. Trim off the head of the bolt with a hacksaw and you have a low cost drilling jig. 

Mark a straight line across the center's of the factory holes using a felt pen and insert the exposed shank into the factory drilled hole and align the two mounting holes with the line. Mark and drill the first mounting hole, secure the nut-plate using a cleco from the rear then drill the next hole. 
Repeat for all the mounting holes as specified in the plans.

Countersinking Nut Pales
If purchasing a new micro stop investigate a slim line for this job especially for those in the rudder fin spar and remember to purchase 1/8'' cutters to suit the selected tool. This builder used an full size economy micro stop that was in the toolbox. 

Note: Countersunk pop rivets have 120 deg NOT 100 deg angle as a solid rivet.

Slim Micro Stop & Cutter

Nut plates should be aligned along the length of the spar especially on the rudder fin. Drill test holes in a piece of scrap and adjust the stop to the correct depth then countersink all the mounting holes and install the plates with 1/8'' counter-sunk pop rivets supplied. When riveting, fix the nut-plate to the spar with a short 3/16'' screw, align hole and pop rivet with the countersunk rivets supplied with the kit.

Countersunk holes have a tendency to find their own centers and are notorious in their lack of accuracy about the hole center-line they are applied on.

This nut alignment was missed by this builder on the rudder stab and resulted in some untidy work to fix the issue. 

Footnote: Countersunk 3/32 pop rivets are available but hard to source and not available from the usual home builder suppliers.
Apex Fasteners have one with a 3.2 mm grip, a bit long but you might get away with it. The gain is not having to drill the lug as outlined and the countersink should fully terminate in the 1 mm spar material. 

Metal Cutting Update

In the previous article about metal cutting examined the use of a Olfa Cutter to trim sheets. Franco at Flying Legend advised that the factory had supplied stainless steel strip drilling jigs. A quick search of the parts supplied identified a stainless steel strip 20 mm wide punched at a 30 mm pitch. This had been packed away with the thought that this looked very important and must therefore go somewhere important - not so. 

Its application is the same as the cutting guide outlined in the original article but its can also be used as a drilling jig for the fixing of components. Begin steel it provides a convenient edge guide when dressing the cutting burr with the file.

The other items shown with the punched strips is the flat strip to manufacture the attachments of the fiberglass tips to the aircraft. The folded 30 x 30 angle is just that, folded angle to allow the manufacture of various brackets as required by each individual aircraft.

Metal Cutting

Drilling jig