Seat & Belts - Finito

This blog covers the work to finish the ftont seat and belt installation

Overview
The motor trimmer was less than enthusiastic to modify the headrests and suggested the use plastic cover to hide the openings then showed a sample - pity he only had 1.5 and did not know what car they came from and the trip to the motor wrecker proved to be just as fruitful.

A pair of 3D models were created, sent to China for manufacture which arrived in 6 days ready to install and where primed, painted in Wyattl Satin Black for installation.

The next task was to cut the openings - with the head rests positioned they were marked from the slots cut in the back of the seat previously using a white fine tip paint marker. With the openings marked the back of the headrest was cut using a X-Acto #11 blade with the foam removed and then shaped using the Dremel Motor tool fitted with their small sanding drum. 

Next the front leather was cut with the X-Acto #11 blade to clear the plastic covers. To allow the headrest to be removed the plastic covers were glued in position using black acrylic sealant. With the cover's in position they were covered with a paper towel and weighed using two house bricks to flatten and hold them in their correct position until the sealant set.

This operation was repeated at the seat back openings using similar techniques.

Trial fit with seat covers installed in the front seat
Compare this to the photo in the previous blog
The foam dust at the top is from the sanding to prepare 
the openings and was hard to remove

Trial fitting the dog clips showed a number of small modification were required to clear the new covers.

Dog clamps

Crutch strap attachment

Lap belt attachment
typical both sides

Adjustable lumber support

Comment
Worked as planned and while the added weight of the full leather covering is an issue, the final appearance and that smell of leather is hard to beat. 

Was it worth - I think so...!

With all the bolts tight this is a solid as a rock for the addition of 
two pieces of aluminium tube. The seat belts just reached using 
the extended D shackles.

Pilots Throttle - Part 2

This blog cover the assembly and installation of the pilot's throttle quadrant.

Overview
With the co-pilot's throttle installed the final installation of the pilot's throttle / quadrant could now be undertaken

Installation
A series of careful measurements were undertaken to allow the Bowen cable to be cut its correct length. 

Mounting bushes

After trimming the wire lock collet was fitted, nipped up and both quadrants connected to test their operation which seemed smooth, once completed it was time to finish the installation of the throttle and choke cables. 

Holes were drilled in the bulkhead at the time of the console manufacture.

To locate the cable ends two [2] T washers were machined from aluminium bar with a 0.5 mm boss, alodined, assembled as shown.  




The cables chosen were McFarlane 101D072 - 6 foot Dual Cable allowing the choke and throttle to be directly connected to the carburetors without having to install splitters or cranks at the firewall. 

These cables ends were fitted with AN665 Threaded Clevis to permit attachment of links from the lever's in the quadrant. 

With the lever and cables placed in the neutral position the connecting links length were calculated. Both links were then fabricated from 3.2mm x 12 mm strip of 2024-T3 with strips of 0.040'' 2024-T3 riveted at one end with 3/32'' pop rivets to form a fork with all parts alodined before final assembly.

Note: links were installed to reduce the chances of binding caused by alignment and to place the connection point at the two [2] access openings.

The choke link was a straight link but the throttle required a turtle link to clear part of the upper throttle frame with the rear throttle clevis directly attached to the throttle arm.

To make assembly / disassembly easier the throttle quadrant was modified with a cutout in the back plate to allow the throttle clevis pin to be pushed out, additionally two more access openings were cut at the front and one at the rear.

Front view main access hatch
Front plate of throttle deleted to improve
access to connection points

After many - many and did I say many installation of the console it was found that leaving the wire attached provided the most efficient means of re-assembly. Also it was found that the front cover of the throttle could be deleted and was removed replaced by packers at each of the mounting points providing a significant improvement in access to the mounting points.

Link and cable attachment from rear
Both links attached using a AN3 bolt and nut
Wire cable attached to the throttle for ease of assembly
Front plate is deleted here

The next task was to manufacture four [4] covers from 2024-T3 0.025'' sheet, cut size, painted to match the console except one [1] which was painted black and will be used to mount the headphone plugs.

To check operation of the cables the console was mounted and the throttle and choke connected. A issue was noted with the operation of the throttle with a distinct small bind and it was determined that deflecting the cable at the bulkhead solved the issue. An angle was fabricated from 0.040'' - 2024-T3, alodined and the throttle cable was secured with a clamp in the deflected position and this seemed to solve the issue. 

Bracket pilots quadrant

Note: No reason could be found as the choke was smooth when checked but may have been that cable but I did not want to swap at this point.

Next the rear throttle was disassembled and re-connected and it was now found that it now not as smooth as when tested, I suspect the McFarlane cables. Again an angle was fabricated to support the outer to hold it in position in operation. This was fabricated from 0.040'' - 2024-T3 aluminium, alodined and mounted to the fuselage side. A rubber grommet supported the cable outer limiting its movement under pressure. This seemed to smooth up the systems operation.

At this point the covers were fitted, fixed using anodized M4 aluminium screws with X-large head M4 used to secure the console just because they look cool..!  

Mounting bolts for the rear were changed to black M5 aluminium again just for appearance.

Pilots Console

Throttle handle and keyed mounting bracket
fixed using M4 cap head screws to lever
with three [3] x M3 cap head screws at handle

Comments 
It's finished with a lot of work requiring with a number of changes while maintaining the original concept.

A push rod as supplied with the factory kit would be the best way to connect the two quadrants but at the time a cable seem the simplest way to connect based on the point of airframe assembly.

That was fun !

 

Emergency Pump - Part 2

This blog covers the plumbing of the emergency hand pump

Overview
The installation of the Cessna style hand pump created a series of problems because of mixing NPT & ISO threads.

Installation

The first issue was the hand pump requiring two 1/8 / 1/4 NPT to M10 x 1.0 custom nipples which were machined from and existing AN6 nipple. 

One  was  was manufactured by machining an M10 adaptor from 16 mm AF 2024-T3 hex bar tapped M10 x 12 deep. Next the AN6 nipple was machined to a OD of 9.08 mm to create a interference fit with the machined hex bar. The other nipple was machined off and the face tapped M10 x 1.0 through. [see photo below]

AN6 nipple machined 
to press fit into adaptor

The hexes on both items we lined up, high strength Loctite applied and the two item pressed together.

Next the Masco Dump Valve had four [4]  Aeroflow NPT to BSP adapters fitted and using a combination of the supplied factory fittings connect both the nylon and braided line.

Hand Pump

Modified AN Nipple
Note: blue is the modified AN nipple

Cutting Braided Hose
The braided hose supplied was cut by wrapping masking tape around the outside and then cut using a sharpened cold chisel. The end was reshaped using flat face pliers then dressed to a smooth finish using a small bench grinder with the tape in position.

Note: FREN TURBO the supplier of the hose dose offer tools for this task

With the tube cut the hole was chased using a 1/8'' rod to ensure the minimum diameter specified by the supplier, finally the braiding was flared using a used pop rivet mandrel to allow fitting of the brass ferrule. Next a ferrule was fitted then tapped with a soft flat hammer onto the end of the nylon tube, finally the nut was position ready to be installed onto the hardware.

Note: The nuts must be fitted immediately after cutting by working the nipplie over the tape with a couple of rotations. The stainless braid is flared exposing the nylon tube with the ferrule tapped on to avoid being pricked by the exposed wire of the braiding.

Before installation each hoses was blown out using compressed air before fitting with all threads treated with Teflon sealant at assembly to secure nuts and provide additional  sealing.

A elbow was selected and fitted to the hose and tighten Next the alignment was checked and if incorrect with the location the assembly was undone, fitting rotated to correct the error. This was repeated until the alignment with the installation point was correct.and the elbow is installed and the nut fully tightened. 

Note:  Once a method for cutting the braided tube was developed it was just time consuming but relatively straightforward.. Never terminate to a straight as uncontrollable twisting is the result. 

Final Assembly

With the hose route finalized all hoses were secured to the air-frame as required using aluminium line separators. All fittings were secured to the side of the wheel well using M3 rivet nuts with pan head screws.  On the underside of the floor they were fitted through aluminium hangers fitted with 'O' rings.

Note: The cut hose was threaded through the openings in the spar before fitting the last coupling.

Finally the dump valve was connected to the manifold using the braided hose and nylon tube all were secured using separator clamps.

Note: Nylon hose is used only on the low pressure side of the circuit.

Comment
Installation worked as planned.

Co-Pilot Throttle

This blog cover the installation of the rear throttle

Overview
A basic throttle was installed for the co-pilot for emergencies and demonstrations. This will be backed up with a removable basic panel to be cover later.

The factory now supplies a throttle for installation but there was one in the toolbox so that was selected for installation. 

Factory throttle option

Note: Remember his aircraft was one of the first kits and there has been a significant reconfiguring and upgrading of the whole aircraft and kits including this one. 

Installation
A mounting plate was fabricated from a piece of 0.020'' x 2024-T3 attached to the two stiffeners located on the port side using six [5] M3 rivet nuts and screws. Next the throttle was disassembled and unwanted material removed especially from the rear plate. Then five [5] M5 rivet nuts were installed into the mounting plate with one [1] installed in the backing plate to act as a friction lock.

Co-Pilots Throttle Quadrant
Note: handle mounted in wrong pivot

With all the mountings prepared the throttle was assembled using the five [5] mounting points. 

To connect the rear throttle to the front throttle a 7/32'' bowden cable was used combined with wire lock collet to provide attachment for the clevis. With the wire lock secured at the rear throttle end, a clevis was fitted and secured to the throttle arm with a cotter pin.

Finally the arm was maneuvered onto the pivot point and secured using a M5 bolt and adjusted to a light drag.

Cable Route
A route for the bowden cable had to be selected as it had been decided to not install a rear throttle to save weight and the complexity but again on the last factory visit I yielded to Franco recommendations.

Clamp

A single 7/32'' was drilled through the roll cage attachment on the point located where the middle bolt is on the opposite side. The cable was run across the face of the backing plate for the map pocket and through the bulkhead behind the pilot's throttle.

Collars

To retain the cable at the roll cage penetration two [2] DuBro 7/32'' collars were installed on either side of the penetration at the roll cage with a bowden cable clamp fitted at the bulkhead at the rear of the pilot's throttle consul. 



At the bulkhead behind the pilots quadrant a 0.040'' 2024-T3 bracket was fabricated and the collar clamp fitted. 

The collet nut was located on the inside face and the collet external face was treated with Loctite No-Sieze at installation there a bear to separate after tightening.

The steel nut was replaced with a AN-4 bulkhead nut and modified to fit as shown - why - its lighter and it was there in the bin. 

At installation the star washer supplied with the collet was replaced with a flat washer and thread lock applied.

Co-Pilot Quadrant

Comment
Tested and operated smoothly and it's one job finished with the biggest task beign mating the rear throttle quadrant with a 50 mm throw to the front having a 65 mm throw which matches the actuator lever on the Bing carburetor.

All the hardware used work as advertised by the suppliers.

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.

Rudder Pedal Upgrade

This blog covers the upgrade of the pilot's rudder pedals

Overview
The factory supplied a new set of upgraded front pedals to replace the existing pedals offering adjustments for the toe brakes and pedals combined with improved operation of the toe brakes. 

Installation
Removal of the existing pedals was straightforward except that the bolts holding the rod ends had thread lock applied at installation and it had seeped between the bolt shank and inside face of the rod end requiring a little heat to be applied.

The front pedals were painted then re-assembled ensuring removal of the locking pins with some other small issues requiring rectification to ensure smooth operation. 

A Century Springs compression spring CH-756 was installed as a trial to the rudder pedal to create assistance or backpressure when adjusting the rudder pedal position and this appears to assist the operation easier and will be installed once the springs are back in stock at the local hardware store.

New factory brake pedals
Note: spring fitted onto brake pedal

With the brake cylinder installed, BSP to NPT adapters were fitted with 3/16'' brass NSR elbows.

The rudder system was locked up as outlined in the previous blog about the rudder cable installation.

Next task was to fit the cranks this required polishing the mounting stubs on both pedals with 80 grit corundum paper with final finishing acheived with 240 grit wet & dry leaving the cranks capable of being fitted by hand.

Setting crank vertical
relative to top of
wheel well

Both pedals were installed, fixed to the rod ends with M6 bolts, cranks adjusted, squared, marked, removed to be cross drilled to suit AN3 bolts and de-burred. Loctite Anti- Seize was applied to the mating faces to prevent surface rust as items like these will weld together over time.

With all the items ready the bearing faces were greased,  assembled, checked and finally reinstalled.




Connecting Bolts

The original bolts connecting the pedals were manufactured to secure the rod end with NO thread in the rod end but removal was more difficult that envisioned. 

Again Titanium bolts provided a plain shank of adequate length with a hex head that was the factory's original design intent and were fitted with a S/S mudflap washer and spring washer for retention.

Note: No grade 8.8 bolts with a plain shank can be found.



Wheel Alignment
A bar was clamped across the front nose wheel and aligned as outlined in the blog on rudder cables.

Finished assembly

Comment

The puppys happy

Supercharger - Why?

FlyGas Supercharged engine at full power

Turbo Charged engine at full power

There have been questions raised about the selection of a supercharger that I would like to answer.

The main reason is illustrated above :

The Flygas supercharger allows the Rotax 912 ULS to develop 140 hp at the prop for two minutes and a 130 hp for the climb with less than 5 HP begin absorbed by the supercharger at full power. Turbos are not totally unrestricted as increased back pressure on the exhaust in operation that will consume some power in operation.

97 kts [180 kph] - 400 f/m - 12000 ft 
Factory supercharged aircraft

FlyGas has delivered about 80 of these units to date and has had no reported issues with their installations in 14 years and worked with Flying Legend to develop the ring mount to suit the Tucano. The factory aircraft now has in excess of 300 hours of operation on this engine with no issues other than the normal maintenance.

The system features a separate oil pump and allows the engine to operate developing 82 HP in the event of supercharger failure.

The simplicity of operation in the fact you open the throttle and like a normally aspirated engine your power is governed by altitude and throttle position. Examination of the power curve shows that a supercharger produces a linear throttle response where a turbo will display a small peak and the rate of power development drop off a little in the last 1000 revs. The other thing I found flying the factory turbo 914 was a constant need to adjust the boost as it crept over the flight.

The final reason is a turbocharger itself while they develop power they have to be controlled as they are effectively only controlled by he wastegate and it is known that is the wastegate failes in any way the pilot only has a small window to control the runaway boost while a supercharger is mechanically controlled by it mechanical drives ratio.

The weight of the supercharged engine is 73kg compared to 78kg for a turbocharged Rotax 914 and 84 kg [est] for a Rotax 915 but that does include an intercooler but watch that space.

Downside
A downside to any supercharger is that it will lose manifold pressure at the rate of 1'' / 1000 feet meaning that this engine developing a 100 hp at 6000 feet, this is where a turbocharger shows its advantage. 

For maximum power, at any height above 6000 feet, a turbo develops a steady output until the turbos physical capacity is reached with the Rotax 915 rated at 130 hp to 16000 feet and this is where oxygen is a factor above 10,000 feet with MOTW raising its ugly head. This will increase the complexity of operation not to mention the problem of recharging the bottle during a trip with this begin the largest issue.

At altitudes below 10000 feet, the engine will develop its maximum design horsepower and as a "What if"  type I am comfortable with that, to run a modified engine continuously at higher power settings you have to consider the risks or use the 915.

The installation planed for this aircraft will result in a lot of items hung under the engine and most do not like red hot items another reason why I chose the lower power to avoid any issues later - it just the conservatives option.

By the way, CASA dose do ramp checks in Australia and if you are found non-compliant on a range of issues you will be issued with a significance fine on the spot and if there are too many issues you will be in a world of financial grief and have a new hobby - plane spotting.

Read the article on the FlyGas supercharger from the EAA Experimenter for a more detailed review of the FlyGas product.

Reference

Discussion on the power consumption of supercharger - very technical but go the last few posts for the wash-up - CLICK HERE