Challenger XL-65 Light Sport Aircraft Build Project

In December, 2011, we received a new Challenger II XL-65 light sport aircraft kit from the Quad City Ultralight Aircraft factory.

As with the XS-50 project, we will chronicle the build on-line as it comes together from receiving the boxes off the truck right through to the test flight and delivery to the customer.

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Dec 12, 2011: Aircraft Kit received. Began unwrapping fuselage and wings and checking for damage and receiving in parts. Hung up wings. Mounted fuselage on saw horses. Cut up boxes and bundled cardboard for re-cycling.
Dec 27, 2011: Continued un-boxing parts and checking off parts from the packing slips. Put parts on shelves and organized. Cut up boxes and bundled cardboard for re-cycling.
Dec 28, 2011: Finished unpacking fuselage. Installed reinforced belly mod using 3/4 x3/4 x 1/16 aluminum angle below the horizontal cross member of the landing gear. Then added 2 gussets about 4 inches in front of the landing gear legs along the 2 sides. This will enable the plane to be lifted from below with a hydraulic ATV lift without crushing the belly.
Dec 30, 2011: Built small storage compartment and large storage compartment behind rear seat using .025 aluminum sheet. Installed FG-99 fabric gusset on tail and small 2×2 gusset for fabric support below tail. Drilled and riveted seat bottoms. Drilled and riveted firewall. Installed tail wheel assembly with Clecoes. Will paint first before riveting in place. Cut rear shoulder harness slot in rear seat back.
Jan 2, 2012: Finished sides of large storage compartment with .025 sheet aluminum. Added 2 more belly reinforcing gussets. Installed sheet metal fabric attachment strips alongside the rear cockpit.
The side fabric attachment trips will provide a good solid area to join the two fuselage fabric side pieces.
Jan 3, 2012: Built and installed an avionics shelf in front of the cockpit. Made the heater pan for the Sheer Tech heater and riveted it in place below the engine area.
The heater pan that will support the Sheer Tech heater is made from .025 aluminum sheet.
Jan 4, 2012: Built a battery mounting box and installed the battery just ahead of the heater pan. Installed a terminal strip for the battery and voltage regulator wiring. Installed the battery wires and grounded the battery negative terminal to the airframe. Drilled holes in the fuselage belly gussets for the wiring and installed rubber grommets. Ran the 12 volt power wires from the battery compartment to the avionics shelf as well as the primer tubing. Drilled holes in firewall for engine wires.
Another view of the battery mounting box just ahead of the heater pan under the engine mounting area. It is made from .025 aluminum sheet and 1/8 x 1/8 stainless rivets.
Jan 6, 2012: Ran the 10 engine wires for the temperature gauges from the battery compartment up to the avionics shelf and installed a terminal strip for the 5 engine temperature senders. Began building the door frames. Installed the ceiling frame and built the right door frame. 3 hours
The engine wires and primer tubes passing through rubber grommets in holes drilled in the fuselage belly gussets.
The rear sheet aluminum surface of the large storage compartment provides a nice mounting area for the voltage regulator (not yet received) and a couple of wiring terminal strips.
The door frames are built on the fuselage. A space is kept between the door frame and the surrounding fuselage frame to prevent interference and wear after completion. The kit includes spacers but the builder has added 4 extra washers on top of the spacers on the side rails to make the space there about 1/2 inch. The other 3 sides of the door have about a 1/4″ space to allow for movement and prevent binding and interference.
Jan 8,2012: Installed streamlined fuselage mod behind rear seat. This will make the door blend into the fuselage. We will also be building a small door here to make easy access to the battery compartment.
The streamlined fuselage modification shown from behind and above. Note the 3/4 inch x 1/16 aluminum angle used to support the curved 1/2 inch tubes just before they curve in toward the firewall. This will prevent the tubes from being pulled down by the fabric when it gets tightened. The tubes are just below the plane of the ceiling frame.
The rear of the door frame and the 1/2 inch tube that forms the fuselage frame. The fuselage frame tube is actually the last tube that would be otherwise used on the door frame but instead is fastened to the fuselage. Its curve matched the curve of the door frame perfectly. Note that STL-16 stainless steel L brackets are used to hold the fuselage frame in place with 3/16 rivets.
The top of the rear door frame showing where it joins the fuselage frame and the ceiling frame.
Jan 13,2012: Built left door and left side streamline fuselage mod. Started battery bay door frames.
Jan 14,2012: Built right side battery bay door.
Jan 15, 2012: Riveted right side battery bay door.
Jan 16, 2012: Built and riveted left battery bay door.
Jan 17,2012: Installed gascolator and fuel system inlet tee with quick couplers. Installed fuel shut off valve and ran fuel lines.
The fuel shut off valve installed in the cockpit right side in the side rail gusset alongside the pilot seat back.
Jan 18,2012: Cleaned and sanded cockpit doors. Riveted cockpit doors. Installed nose cone storage panels. Installed fire wall extension sheet and installed sound proofing foam sheet.
Storage compartments are made in the nose cone by installing a sheet metal panel on either side of the nose to close of a space between the panel and the side of the nose cone. Great for water bottles, maps, flight supplements, etc.
Sound absorbing foam sheeting 1/2″ thick with adhesive backing is placed on the inside of the firewall.
More sound absorbing foam on the back of the large fuselage storage compartment.
Jan 30,2012: Built and installed the rudder push rods. Installed the landing gear legs into the weldments, drilled and bolted. Installed the tail fin and drilled bolt holes in fin weldments. Installed the rudder. Then fabricated the fin extension over the rudder and drilled and riveted. Drilled holes for rudder hinge rivets. It is important to install the rudder first matching the bottom hinge to the eye bolt on the fin mounting weldment. Then fabricate the fin extension to match the height of the rudder.
The XL-65 tail varies from the LSS tail shown in the instructions in that the fin extension over the rudder is shorter in height. The best way to build it is to first install the rudder and then fabricate the fin extension over top of the rudder to suit.
The fin extension is kept straight and true during fabrication by clamping a pair 3/4 inch aluminum angles to the fin and the extension assembly. The gap between the fin extension and the rudder is about 3/8 inch.
Start with the bottom rudder hinge and build upwards. The fin extension is then built to suit the rudder installation. The bottom of the rudder should be placed so the the rudder horn (not shown) is level with the center line of the bottom horizontal tube on the fin. The rudder travel stop mounted on the rudder horn will strike a stopper mounted on this tube.
Jan 31,2012: Installed and drilled the axles. Installed the brake calipers. Assembled the main landing gear wheels and installed. Marked and drilled the mounting holes for the dorsal fin. Sanded the firewall, heater pan, root tube over engine in prep for prime and paint. The picture shows the axel housing taped in place. A 5/8 tube (arrow) in the axle housing holds a laser pointer (circled) which allows the axle shaft to be aligned with the gear leg on the opposite side. The laser is pointed just behind the center line of the other gear leg. The starter drill hole for the 1/4 inch AN4 bolt to hold the axel housing is in the square. Drill this hole in 1/64 steps up to 1/4 inch to maintain accuracy and avoid breaking a drill bit.
The axle shaft has been installed with the key way facing up. The 3/16 hole has been drilled on the inboard side of the housing to hold the axle in place and the bolt installed The hydraulic brake caliper is now mounted on the axle. There are 2 hidden set screws underneath that must be removed, dabbed with blue Loc-Tite and reinstalled.
The tire can be fitted to the rim assembly by squeezing the outer edges of the tire to force the inner edges outward on to the rim. I use ratcheting straps. The inner edges of the tire and the rim should first be lubricated with some light oil to facilitate the rubber sliding over the metal. Then fill the tire with air and, if you have a fairly good tire to rim seal, the tire will slide onto the rim with a loud pop. There are a lot of forces involved so the 6 bolts holding the rim together should all be fastened down tight for this process. The assembly area and the rim parts should be kept clean to avoid metal filings or dirt from causing air leaks in the assembly.
The main landing gear wheel and brake assembly temporarily installed. The tire is inflated to 25 psi. The assembly will later be fitted with the wheel pant and the gear shaft with the streamlined cover. So the axle nut is not tightened down yet.
Feb 6,2012: Masked off the fuselage for painting the engine mount root tube, firewall and heater pan, and the cockpit area tubes. Sanded and cleaned tubes with MEK. Blew out dirt and metal chips with blow gun. Primed the metal with galvanized metal primer.
Also cleaned up my shop in the basement and unpacked the Rotax 582 engine and put it up on the work bench. Now ready to invert and install the hoses and brackets.
Feb 7, 2012: Painted cockpit tubes. Started the 582 engine conversion. Cut the motor mount casting. Cut and fitted the cover plate. Removed the pull start assembly and installed the electric starter motor.
The Rotax 582 engine with the GPL electric starter motor installed where the pull start used to be.
Feb 10,2012: Assembled nose wheel and then installed the nose gear assembly. Installed the rudder pedal push rods. Fabricated an electrical box for the fuse block and the power bar. Installed mounting support angles for the electrical box. Installed 5 terminal strips on the avionics shelf.
Feb 12, 2012: Started engine conversion to inverted position. Moved slide valve oil reservoir. Installed exhaust manifold. Installed one coolant hose for running up to radiator.
Feb 13, 2012: Continued engine conversion. Installed EGT, CHT, and coolant temperature sensors and spark plugs. Installed fuel pump, carburetors and fuel lines. Installed heater assembled and air hoses into fuselage.
The carburetors and fuel pump installed.
The heater installed in the heater pan below the engine area with forced air hoses installed and running up to the cockpit area.
Feb 14, 2012: Fabricated top cover for electrical box. Wired up the heater. Wired up the wires from the engine sensors to the terminal strips on the avionics shelf and labelled them. Sprayed primer on the door frames, electrical box and its support brackets. Drilled holes for the strut brackets in the horizontal stabilizers.
Feb 15, 2012: Painted the electrical box and its support frame and the ceiling frame. Installed the nose cone, cut the hole for the nose wheel shaft, and drilled the mounting holes. Installed the sheet metal blending strips for the nose cone. Installed the shoulder belts. Installed the wing spar Rony brackets to the root tube. Installed the electrical box on its support frame in the nose. Trial fitted a cardboard pattern of the instrument panel. Laid out the instruments on the panel pattern.
A cardboard pattern of the instrument panel is fitted. It is going to be a large full panel so theis design will maximize available space but also will leave room for tall pilot.
The instruments are laid out on the cardboard pattern to check for fit.
The sheet metal pieces that blend the flat side of the fuselage to the curved side of the nose cone.
Feb 17, 2012: Did some more wiring in the battery compartment, electrical box and the avionics shelf.
Feb 18, 2012: Installed the transponder antenna on a lexan sheet on the cockpit floor. Cut out a sheet metal ground plane for the antenna and installed. Laid out the cut line for the flip up nose cone.
Feb 20, 2012: Drew the panel layout on a sheet of .090 aluminum and cut the panel outline shape and cut out the switch and instrument holes. Mounted the altitude encoder on the electrical box.
The intrepid builder drilling and cutting out the holes for the switches and instruments on the aluminum sheet that will make up the instrument panel. Note the grim determination on his face. Note also the safety glasses and hearing protectors. It’s a noisy business with lots of flying metal bits.
The sheet aluminum instrument panel after an hour or so of drilling and cutting with hole saws.
Feb21, 2012: Fitted the gauges and other components to the instrument panel. Fitted the panel to the cockpit and made up mounting brackets. Sanded and primed.
The mounting brackets are fitted with anti-vibration threaded mounts to protect the expensive avionics and gauges from the vibrations and bumps that will be encountered in service. these mounts are bolted to the 1″ diameter 2FB-1 vertical fuselage brace tubes with 3/16 AN bolts. A fifth vibration mount at the top of the panel provides additional stability to the panel.