Tie Down

This blog covers the aircraft tie down method

Overview
This aircraft cannot afford to carry 3.5 kg of tie-down's, a search located the "Orange Screw" at 125 grams each that would seem to fill the bill. The plastic tube acts as a handle while providing a cover for any dirt when stored in the aircraft.

Comments
Light weight 

Baggage Compartment - Pt 4

This blog cover the installation of an access hatch to allow the installation of the pump and battery is required behind the existing compartment.

Overview
On the last visit by the factory the C.O.G issues were discussed and Franco indicated that the new aircraft kits feature a baggage compartment behind the existing one. At the time I had the parts for a battery access hatch and chose to install the battery on the existing battery compartment shelf along with the pump.

When the new hatch arrived I was stunned by its size compared to the original hatch. 

After a bit of thought it was decided to install the hatch so in case of issues with c.o.g. at the final weigh in the pump could be relocated back further or the same battery that the factory installs fitted. 

Put simply a back door to escape any issues that may be created by the selection of the lighter battery.

Installation
The first task was to mark out the opening this was done by sticking the laser cut doubler to the side of the fuselage and then marking out the cut line with masking tape. With the outline marked a metal guide was fixed to the cutting line and the four side scored using the Ofla knife and then the scrap broken out. 

Marking the opening

Scrap ready to be removed

A steel ruler was fixed to the opening edge and then opening slowly dress to a final size.

Fitting filing guide

Finished opening

With opening prepared the cover was checked for fit and final adjustments made. Next the the cover was refitted and the 2.5 mm holes matched drilled into the fuselage skin, at this point the factory flange was removed and the doubler clecoed into position on the inside face.

Note: The opening was meant to be installed into the opposite side but this clashed with the circular opening installed to access the antenna base - this opening renders that access hatch of no value.

At this point it was decided to install a C channel at the top edge using the existing holes to secure the channel. 

The external door was curved by hand and by rolling across the builder leg to pre form the profile to the fuselage side to reduce the possibility of distortion when installed.

With the channel installed a piano hinge was trialled but it proved not to be suitable so an alternative was required. It was decided to use a series of plain M3 rivet nuts as studs engaging into the channel using a series of the original rivet holes.

A 0.020'' [0.5 mm] angle was folded to accommodate the angle created between the door and the fuselage this was riveted to the door cover using the same center as the doubler. Next the 5 [five] selected rivet holes were transfer to the angle and then the rivet nuts installed then the corresponding holes were enlarged to 5.5 mm to accommodate  the rivet nut shank.

Channel detail baggage compartment
Larger holes are for the studs to engage into with the
other smaller holes left over from the piano hinge installation

A quick check revealed it would work and a large sigh of relief was exhaled.

The factory doubler is cut for quick release fastened so this required the holes be filled for M3 rivet nuts. This was achieved with 0.020'' aluminium fixed across the opening using the two rivet holes provided, dimpled and riveted with 3/32 pop rivets. 

Door - upper locating lugs created from plain shank M3 rivet nuts

With opening covered the mounting holes were drilled from the cover, enlarged to 5.8 mm and M3 rivet nuts installed. The cover holes were now enlarged to 4.5 mm for ease of assembly. 

Baggage compartment and frame
M4 rivet nuts installed to fix door

A 5 degree fold was applied along the lower fixing line stiffening the lower edge of the cover.

After a few final adjustments the door fitted reasonably neatly and is now ready if needed.

Tools
A new dimpler was purchased to supplement the existing dimpler - proved its worth on this job and created a fairly crisp rows of countersunk holes for riveting.

Comment
Done and I will finish the back end if it kills me....!

Did not take a happy snap of the door installed but it fitted with a  9.0 out of a possible 10 with the lugs working well.

Baggage Compartment - Pt 3

Note: The final location for the pump is at the revised access hatch shown in part 4 - it improved cog and access - See comments at end of this article

This blog covers the installation of the hydraulic pump into the baggage compartment.

Overview
The decision to relocate the hydraulic pump with the battery was a direct result of the factory supplying a spreadsheet for the weight and balance for the Tucano showing that the Tucano Rs having a particular problem created by the 7 kg of the additional weight of the supercharger.

This led to the factory supplying an engine mount shorter than a standard 912 engine mount to suit the supercharged model.

Estimated C.O.G.

What does this show this builder - A Tucano is very sensitive to weight on the nose wheel, so great effort must be expended firewall forward on weight control or balance it by moving items that the aircraft requires to the most advantageous location.

The factory currently installs its 5 kg battery behind the baggage compart wall but this option was not taken as the amount of re-work required was not acceptable and in the end a 30% loss of area in the baggage compartment was considered acceptable for the style of operation contemplated for this aircraft by the builder

A battery and pump have a 5 kg combined weight matching the factory battery weight. Remember this aircraft uses LiFeO4 battery pack [1 kg] with this combination 3 kg lighter overall.

Installation
The first task was to install the battery, and this was covered in an earlier blog.

Next, the pump was removed from the factory location, the base was removed and two more feet were fabricated from 0.040'' 2024-T3 and installed. The location of the feet was marked onto the floor, M5 rivet nuts were fitted then 25 mm studs were installed into the rivet nuts with thread locker.

New mounting feet

Two 50 x 6 foam isolators were installed over the studs to provide some noise isolation, but this may have to be upgraded at some time after the noise is evaluated. 

Local wildstock
Grommets and isolator pads

Four [4] x 1/4'' id rubber grommets were fitted in the deck, providing an exit for the four lines to be run back to the original location under the co-pilot seat. 

To support the four [4] lines, these are mounted using AN3 (1/4") aluminium hose separator modified to allow a M3 x 35 S/S unbrako securing the assembly to the aircraft with a M3 rivet nut. 

A series of these were used to hold the lines clear the seat belt running under the passenger seat mounted on a 0.020'' x 2024-T3 folded bridge under the seat.

Hydraulic pump with protective cover

Propellor controller is located in the pump's old location

Lines from pump loose on rhs
Hydraulic lines and supports will be covered
in a separate blog

Comment
Not the preferred option, but it was practical at this time mainly due to access to the skins secured in this area and will meet a goal. Doing it again, the pump would be mounted behind the baggage compartment, especially if using lightweight batteries again.

The actual hose runs came out better than they should have, as it was all done on the fly.

PS:  Most of the blogs are prewritten to provide a plan of attack, and the seat belts were very difficult, especially the shoulder straps and have been redesigned numerous times, so text from previous thoughts [plans] were still left behind - fixed.

Baggage Compartment - Pt 2

Finish the baggage compartment to gain the points assigned under AC29.21

Background
What restrictions are placed on the aircraft after completion is a function of having to protect third party's. As an experimental aircraft pilot I am free to kill himself in any manner I chose's but not a third party. In fact a TC only responsibility is to the third party and the only control are restrictions so the closer the project is to the FAR's the less restrictions the builder can expect on the aircraft's use.

Restraint of object's in the baggage compartment is a requirement as tie downs and other items can be free to fly in a survivable accident.

Cover's
The cover's consists of two [2] separate panels manufactured from 0.025'' 2024-T3 aluminium sheet with the lower one hinged and the upper one fixed with three [3] Pro-Bolt quarter turn clips.

The lower panel was cut from the aluminium sheet and a 20 mm aluminium piano hinge was fixed to the lower edge with 2.4 mm [5/32] pop rivets pitched at 30 mm. The upper edge had a piece of 12 x 12 x 1.5 aluminium angle fixed from the top edge and fixed with 2.4 mm [5/32] pop rivet's pitched at 60 mm. 

The location of the rivet line was set to be about the center of the uppers panels channel rivet line to avoid one rivet head resting on another.

Lower panel trial fit

Angle stiffener - short to clear bulkhead

Upper Panel

Bulkhead layout

The upper panel was profiled to suit the turtle-deck and to overlap the lower panel and was fabricated from the same material as the lower panel.

A angle was fabricated  from 0.020'' 2024-T3 - 35 x 10 mm and then fixed to the lower edge using 3.2 x 6 mm pop rivets pitched at 90 mm in two [2] rows.

The fastener's are secured with dome head pop rivets but these stopped the panel laying flush, so the solution was to add a series of rivets series around the bulkhead perimeter to support the panel. 

A 10 mm wide strip of foam was added at the edge of the panel to close the visual gap after painting. 

The top panel was secured using three [3] Pro-Bolt Quarter turn fasteners as discussed in Part 1 of the baggage blog. This arrangements negated the need for any locking mechanism other than the fasteners as the upper panel traps the lower panel and the channel transfers the loads into the lower fasteners.

Final assembly - final details parts yet to be fitted

Comment
The only change would be to locate the lower attachment points to the angle center to create a stronger connection. To solve this an angle stiffener will be added once the clips arrive also the D handle is a little long and may be looked at later.

Baggage Compartment - Pt 1

This builder chose to fabricate the components for a closed baggage compartment from 0.025'' 6061 T-6 aluminium sheet. All panels were fitted using 1/8'' x 8 mm pop rivets. To restrain the baggage and front door quarter turn aluminium D ring's from ProBolt Australia were selected. Each clip and ring weigh 10 grams and four [4] points were added to the front and rear. A set of lightweight straps 2 meters long x 25 mm wide with plastic clips are fitted to restrain a load. Maximum weigh allowed in the baggage compartment is 10 kg and is for soft or bagged items only.

Tape skin into position - factory supplied

Prime factory rear panel for installation

Installation of the back panel requires removal of the compartment top skin and turtle deck by drilling out the factory temporary rivets to allow the rear skin to slip behind the factory bracket. Match drill bulkhead from the factory bulkhead - cleco and rivet. The bottom edge should be riveted before fitting the turtle deck skin. This will be a combination of the D ring clips rivets with filler rivets in between at using factory pitch as the guide.

Rear bulkhead

Drill out the four rivets at the back to allow the rear panel to slide behind the other bracket on the other side. Tape the rear panel into position and match drill the holes from the panel through the rear former. 

Match drill through the existing four holes in the bulkhead through the back panel. Once complete reassemble using clecos and rivet using 1/8 x 8 mm pop rivets. 

Creating slot

Connecting Flange

The next task is to adjust the front bulkhead flange to engage with the skin. Start by cutting on the center of the existing holes starting at third hole from the bottom. The top stringer is de-riveted and its connecting flange bent into alignment . 

Cut a V at about 5 degrees at each  side of the initial cut. Use a 5/32'' chain file to open the cut and form a half radius into the edge of the flange. [refer photo]

Bend the top tab into alignment with the spline and cleco. The others are bent using your hand forming a smooth transition from the top to the side. This is not a critical operation, you just need a smooth transition between the tabs.

Front bulkhead      -       Rear bulkhead tabs

Refit the skin using clecos to re-align the front bulkhead. The rear bulkhead has two separate extensions pieces that project into the baggage area. The slots are just slightly visible on this aircraft and were a possible source of leaks as the skins are not lapped at this point. Both were covered with self adhesive aluminium duct tape that was on hand. On the port side simply cover from the base to the center line of the spline. On the starboard side the tab was de-riveted, covered and trimmed to size. The exposed ends had scrap backing reapplied to allow re-installation by sliding the tape between the skin and the bulkhead

At this point preparation for installation of the turtle deck was next.