New Challenger XS-50 Aircraft Build Project

On March 30, 2011, Lake Aviation began assembling a new Quad City Ultralight Challenger XS-50. We will record and chronicle this new aircraft build here on our web site with written commentary, time used for each task, and detailed photos of the project as it progresses.

Check in often to watch our progress as this great new aircraft comes together.

This aircraft was finished in September and flew in November. Read about the test flight and what we thought about the new clipped wing model Challenger here at the XS-50 Test Flight page. Scroll to the bottom of the page for that article.

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March 4, 2011 – Ordered Flip Up Nose Cone Hinge from Aerolite Flight, Throttle and Choke Quadrant and Hidden 3 Litre Oil Tank from Bob Robertson at Aero Controls, and DDM-SL 12 volt Strobe Lights from Kuntzleman Electronics.	No Picture
March 8, 2011 – Purchased battery, fiberglass kit, 4″ duct hose and aluminum angle at Canadian Tire.	No Picture
March 30,2011 – Kit Received. Began to unpack, take inventory and check for damage. 1-1/2 hours.
March 31, 2011 – Continued unpacking and disposing of cardboard and packing materials. 2-1/2 hours.
April 1, 2011 – Finished unpacking and checking inventory. Bundled cardboard for recycling. Mounted fuselage on tables for work. Hung wings and tail for temporary storage in shop. 6 hours.
April 3, 2011 – Made battery mount platform in nose in front of rudder pedals. 4 hours.
April 4, 2011 – Cut, drilled and riveted fabric flanges, seats, firewall. Drilled for tail wheel. Laid out instrument panel. Built avionics shelf and storage pockets in nose. 6-1/2 hours.
April 5, 2011 – Installed shoulder harnesses, built small storage compartment above and behind rear seat, mounted strobe driver box, installed flaperon control, temporary install of top door frame mount, installed aluminum angles between rudder pedals for avionics. 8 hours.
April 6, 2011 – Sanded cockpit tubes and framework, top door frame, rudder pedals, tail wheel mounts, twin tail tubes and root tube over engine area. Cleaned metal with MEK, masked for painting and sprayed with primer. 5-1/2 hours.
April 7, 2011 – Sprayed 3 coats of Tremclad paint on metal pieces and cockpit area, tail booms, and engine root tube. 2-1/2 hours.
April 8, 2011 – Removed masking and reinstalled rudder pedals and nose storage sheets. Installed top door frame. Made rudder push rods and primed. Mounted fuel shut-off valve in fuselage side gusset. Mounted avionics shelf. Mounted starter solenoid and 4 electrical terminal strips. Installed rear fuselage formers below engine compartment. Painted nose gear blue. 5 hours
April 9, 2011 – Painted rudder pedal connecting rods 2 coats. 1/2 hour.
April 10, 2011 – Installed rudder pedal connecting rods. Installed belly reinforcing angles around gear leg. Made instrument panel mounts. Fitted nose cone. 2 hours.
Belly stiffening aluminum angles are to strengthen the bottom of the airframe so that the aircraft can be lifted from below the belly with a hydraulic lift at the center of gravity to change tires or install skis.
April 11, 2011 – Cut nose gear hole in nose cone. Measured, marked and cut nose cone for flip up hinge mod. Drilled fuselage gussets for wires and ran colour coded EGT and CHT wires, ignition and alternator wires. Drilled holes in firewall for engine wiring, wired up battery and solenoid, and connected fuel lines to fuel shut-off valve. 6 hours.
50 total hours of labour mark at this point in the build.
April 12, 2011 – Made fibreglass flange on nose cone for flip up mod. Drilled more holes in firewall for engine wiring. Built electrical power box for rectifier and fuse block. Primed and painted power box. Marked out and began drilling holes in custom instrument panel. 5 hours.
April 14, 2011 – Installed fuse block and rectifier into power box and mounted box in nose and began wiring. Installed rudder pedal to nose gear connecting rods. Cut holes for gauges in instrument panel and fitted gauges. 3-1/2 hours.
The custom instrument panel made to accommodate the customers request for a panel mount radio and transponder, electrical accessory outlets, primer pump and switches for all of the electrical equipment.
April 15, 2011 – Trimmed nose cone flange, installed nose hinge and mounted on nose of aircraft. Finished cutting instrument panel, sanded, cleaned, and primed. Painted instrument panel. 5 hours.
The instrument panel with holes cut.
April 18, 2011 – Painted instrument panel another coat. Built right hand door. Clecoed in place. 2-1/2 hours.
April 19, 2011 – Finished door frames, cleaned and sanded door tubes, and riveted tubes together. Installed streamlined fuselage modification. Cut out and installed lexan ceiling with clecos. 8-1/2 hours.
The streamlined fuselage modification blends the doors directly into the side of the plane. It looks nice when the plane is finished. It adds a bit of drag when flying with the doors off because that area is a little wider to meet the curve of the doors.
April 22, 2011 – Installed doors hinges to ceiling frame. Rivetted lexan ceiling in place. 1-1/2 hours.
April 24, 2011 – Replaced bent fuselage gussets with replacements received from QCU. Drilled holes for tubes and wires in new gussets. Installed rubber grommets and ran wires and tubes through. 2 hours.
April 25, 2011 – Installed reinforcing angles on streamlined mod to prevent it pulling back when fabric shrinks. Made top for electrical box and mount for altitude encoder. Made heater box and primed and painted it. Installed bottom angle that blends belly to nose cone. 6-1/2 hours.
April 26, 2011 – Installed instrument panel and wired it up. Installed altitude encoder on cover of electrical box. 8 hours.
May 1, 2011 – Wired 12 volt outlets on instrument panel. Installed magnetic compass and turn coordinator on top of panel. Drilled holes in fuselage gussets for throttle cables. Made pattern for large storage box behind rear seat. 2 hours.
May 2, 2011 – Built large storage box behind rear seat. Made throttle mount patterns for new LSS style side rails. made front and rear throttle mount brackets and clecoed in place. 6 hours.
The large storage compartment is made of .020 sheet aluminum and is 14″ wide by 16″ long. This is made so that any stored items can not interfere with or jam the aileron controls which are located along the sides or the elevator control torque tube which passes below it.
100 total hours of labour at this point.
May 3, 2011 – Mounted lexan on door frames, drilled and clecoed in place, and trimmed and fitted. Then removed for painting door frames. Installed electrical terminal strip on platform below engine for EGT and CHT sensors. Installed terminal strip on ceiling lexan above rear seat for fuel probe wires. 6 hours.
By placing high intensity lights behind the lexan sheets the aluminum door frames are clearly outlined in silhouette and are then easily seen for drilling the 1/8″ diameter holes for the rivets. The sheet is held up first by masking tape, then by cleco rivets. After trimming and cutting to size, the lexan window is removed and the door frame is primed and painted. Final installation will occur at the end of the aircraft build. It is a coincidence that the yogurt container on the top of the aircraft containing the cleco rivets is brand named Silhouette. Inspiration comes from strange places.
May 9, 2011 – Built and installed the tail and control surface hinges and the horizontal stabilizer struts. 6-1/2 hours.
Note: The XS-50 and XL-65 tail assembly is different from that of the LSS model. The instructions are for the LSS model. The dimension for the distance of the U-shaped cross piece from the top of the fin extension above the rudder should be about 8-1/2 inches not the 11-1/2 inches shown in the LSS instructions. A note has been added to the instructions on more recent kits.
Because the fin extension is about 3 inches shorter than that on the LSS model, the rudder assembly is moved upward on the fin. This moves it away from the eye bolt that normally mates with the hinge assembly on the rudder. It becomes nearly impossible to make a sturdy hinge section on the rudder that will properly mate with the eye bolt because of the lack of room available on the rudder tube. To overcome this, I have installed a 4 piece hinge assembly up a few inches above the base of the rudder. The extra hinge pieces can be borrowed from the trim tab assemblies or ordered from the factory. The higher rudder on the XS and XL models also causes the rudder travel limits to miss striking the horizontal tube on the fin. A sheet aluminum piece or lexan piece will have to be installed on the fin after covering to provide and striking surface.
The horizontal stabilizers and elevators are installed with clecos and tape. This will all be disassembled for covering with fabric and then reassembled permanently with rivets. A building tip is to level the aircraft lengthwise and side to side and then install the horizontal stabilizers and use a level to get them just right. Masking tape from the top of the fin holds them in place while you level them.
May 10, 2011 – Installed dorsal fin and the dorsal fin sheet metal extension. Made the elevator control rods. Install the heater duct and restrained it so it would not interfere with the elevator torque tube. Installed sound proofing foam on the fire wall and the rear outer surface of the storage compartments. Installed the gear legs and drilled the holes for the 1/4″ bolts. Installed the nose gear fork. 7-1/2 hours.
The sound proofing foam is from Aircraft Spruce and hopefully will make the cockpit a little quieter on this aircraft. It is sold by the linear foot and comes in a 4 foot wide roll. It has a very strong adhesive backing. Just measure, cut, peel and stick. This installation uses the 1/2″ thick foam. It is very light weight.
More sound proofing foam shown here on the back side of the storage compartments.
The heater box will have a control cable to direct hot air trapped from the air cooled engine into the cabin or out into the air stream. This is a general copy of a model previously made by Turbulence Aviation but now discontinued due to slow sales.
Another view of the heater box for the Rotax 503 engine equipped Challengers. It is made from .032 sheet aluminum. Vinyl duct work will connect the heater box to the engine. It will be attached with industrial strength velcro and will be easily removable for summer service.
May 13, 2011 – Installed weldments onto main gear leg shafts. Drilled and bolted. Installed hydraulic brake lever onto control stick. 1-1/2 Hours
May 16,2011 – Installed tire valves onto wheel rims. Assembled tires onto wheel rims. Installed nose wheel onto fork. Installed main wheels and brake calipers onto shafts inserted into gear leg weldments. Drilled hole through weldment into axle shaft and bolted. Ran 3/16 hydraulic line from brake cylinder on control stick along torque tube to tee fitting and then to the brake calipers. Filled with brake fluid and bled system of air. 4 Hours.
The hydraulic lines must be tie wrapped in place and also allow free and easy movement of the control sticks and torque tube. The tube must never kink or interfere with control movement.
The first time I installed Hegar brakes and wheels on a Challenger the wheels came fully assembled. This time the tires and rims were not assembled. The Hegar instructions did not explain how to install a loose tubeless tire onto the split 2 piece rims. Here’s how it can be done. First bolt the rims together on the inside of the tire. The sealing disk with the O-ring seal on it should be in between the two rims. Now clamp the two edges of the tire with ratcheting straps. This will cause the inner edges of the tire (the sealing bead) to push out and contact the rims.
Lubricate the rim with some light oil (NOT WD40!) or soapy water. This will enable the rubber to slide over the aluminum rim during the next step.
Now slowly inflate the tire with compressed air. Air pressure should not exceed the maximum pressure shown on the tire which is 50 psi. This should cause the tire to pop onto the rims and fully set in place.
The brake assembly mounted on the axle without the wheel rims and tire.
The weldment and axle must be drilled and bolted to hold the axle in place. The hydraulic line is connected to the compression fitting on the hydraulic brake caliper. The fitting above the compression fitting is a bleeder fitting. When the bleeder fitting is un-threaded slightly it will allow any oil with bubbles of entrained air to flow out and be directed into a container. Push a piece of clear 3/8×1/4 PVC tube over the bleeder here at the caliper and another at the brake lever. Pump oil through the PVC tube at the brake lever using the oil can pump sent with the kit. This will fill the system and bleed it simultaneously. Then re-tighten the bleeder fittings and remove the PVC tubes. Give the tires a spin, pull on the brake lever and the wheels should stop and lock.
May 18, 2011 – Lowered aircraft down from saw horses onto landing gear. Brought left wing down from wall and un-boxed all the wing parts. Assembled wing ribs and end boxes to bottom of left wing and rivetted. 7 Hours.
First step in assembling the wing was to lay it bottom up on the work bench and label the front spar and wing tip and root so there is no chance of messing that up. (The rear spar is identifiable because the 2 holes for the lift strut angle inward, but the holes on the front spar are both located exactly on the leading and trailing edge of the spar.) The next step is to measure and mark the rib locations and tape the ribs in place. Note that the locations of the first and second ribs at the wing root is 1-1/2″ from the end of the spar not 2″ as shown on page 3 of the instructions.
Take the W5X brackets and drill the rivet holes and file off the sharp corners. Next fit the ribs onto the spars. This requires some filing to get them to sit down flush and to take of the sharp corners. Then tape them down and drill the ribs into place through the W5X brackets and cleco them in place.
The boxes at the wing root and tip do not use the W5X brackets, they just use the 8″ wide sheet metal at the root and the 6″ wide sheet at the tip. The rivets going into the spar are 3/4″ apart. The rivets going into the ribs are 3″ apart.
The W5X bracket and a bottom rib clecoed in place.
Two of the ribs are formed from U shaped sheet metal channeling. This has to be cut at the ends to fit around the large factory installed brackets holding the compression struts. These have to be levelled so that they are flush to the same level as the other ribs. Then they are drilled and rivetted to the compression struts in 8 places.
May 20, 2011 – Assembled wing ribs and end boxes to bottom of right wing and rivetted. 4-1/2 Hours.
A pneumatic rivet gun is really helpful because the wings use hundreds of stainless steel rivets. They can be built with a manual rivet gun but the pneumatic unit saves one the bone jarring jolt that occurs with a manual gun. Sonia is taking the pictures and is making me laugh.
The U Channel ribs are used in 2 places over top of the compression struts because a standard 1/2″ tube rib will not fit over them.
May 23, 2011 – Drilled rib attachment gussets for top of right wing and filled off sharp edges. Filed off sharp edges and de-burred ends of ribs for top of right wing. 2 hours.
May 24, 2011 – Marked and drilled top of ribs for fabric rivets. Measured and marked wings for rib placement. Built wing root box and wing tip box. 4 hours.
The wing root box has a sheet metal “webbing” on the end to further strengthen the structure. It consists of 2 pieces with a gap in between for the fuel line to pass through. Another much smaller sheet metal piece reinforces the opposite side.
The wing tip box clecoed together. A webbing of sheet metal will be installed here as well to strengthen this box. The 1.25″ sheet metal overhang will accommodate the fiberglass wing tip and allow some flexibility to match the exact shape of the wing tip.
May 30, 2011 – Installed top wing ribs and leading edge wrap and fitted with clecoes. Installed wing tip box webbing. 2 hours.
May 31, 2011 – Drilled and Riveted leading edge wrap. Installed gussets on both ends of wing ribs (front and rear), drilled and riveted. Riveted wing tip and wing root boxes and webbings. Installed smaller wing box in the middle of the wing root box and riveted. Installed the wing fuel tank. Installed the sheet metal wrap over the fuel tank with clecoes. 6 Hours
The right wing tip box and webbing riveted.
The right wing root stiffener box. This is located about midway along the camber of the wing root box and adds further strength and rigidity.
Another view of the right wing root. The bottle of Windex is to clean my glasses as it was 85 degrees F in the shop when I was working.
The wing mounted fuel tank installed with the sheet metal wrap clecoed in place. Wing rib webbing will be installed on either side of the tank and more stiffeners beneath the sheet aluminum wrap. Plus the fuel level senders and the fuel line to the engine.
June 6, 2011 – Lots of measuring, drilling, clecoing and riveting.Installed leading edge wrap C channel stiffeners and also the round stiffeners underneath the fuel tank wrap. Installed the rib webbing around the fuel tank area and the aluminum angles to hold the tank in place. Cut the filler neck hole and drilled the fuel level sender hole and fuel outlet hole. Cut and bent the fuel level probe. Drilled holes for fuel lines and fuel level sender wires in the inboard rib webbings and installed grommets. Installed fuel line. 8-1/2 hours.
The sheet metal work around the fuel tank plus the aluminum angles to hold it in place.
The leading edge wrap has C channel stiffeners installed between the ribs and half way back to stiffen the sheet and prevent in from buckling along the curve.
The larger area leading edge wrap in front of the fuel tank has two rows of stiffening tubes below the sheet metal to prevent it from buckling.
We are at the 150 hours of labour point on this build.
June 7, 2011 – Installed strobe light on fiberglass wing tip and ran wires through to the wing root box. Riveted the wing tip on to the wing. Installed the fuel tank outlet fitting, the filler cap and the fuel lever sender probe. Wired up the fuel level sender and ran the wires through grommets to the wing root box. Installed the fuel tank metal wrap and the short rib. Ran the fuel line from the tank to the wing root box. The fuel tank is now completely and permanently installed. Cut the aileron to length and installed the hinges with clecoes. 7 hours.
The wing box has been drilled and fitted with grommets from the wires and fuel line to emerge ready to connect to the fuselage section.
The fuel tank outlet fitting must be installed from the inside of the tank. The opening for the fuel cap is too small to get an arm through and is about 30 inches away from the fuel outlet. How do you get the fitting to come through the 9/16″ diameter hole at the back of the tank? Use a stiff wire, like a coat hanger, and make a small 90 degree bend at the top end. Slide the fuel tank fitting onto the wire and push it up to the top end. Then feed the wire through the filler cap hole and out the outlet hole. Then slide the fitting down the wire. Pull the wire down and pull the fitting through the hole using the 90 degree bend to push the fitting through. Insert the washer and nut onto the fitting. Feed the wire back through and out the filler cap hole. In the picture, I have used the factory supplied throttle cable wire with the adaptor on the end to accomplish this procedure. I was not going to use it because I always install an after market throttle quadrant and do not use the factory throttle cables.
The fuel tank finished. It is strapped down with 4 worm drive clamps and fenced in with aluminum angle and sheet metal. The wires come from the sender which is to the rear of the filler cap. The outlet line comes from the very rear and bottom of the fuel tank.
The aileron / flaperon should be trial fitted with tape and clamps to ensure lots of friction free movement up and down. The hinges must be placed so they do not interfere with aileron ribs or the area where the strut will attach. Pieces of 3/8 plywood pushed between the aileron and wing ensure the distance is consistent and gives plenty of travel.
This aileron / flaperon will have lots of travel.
The right wing is hung from the ceiling and the left wing brought down to work on.
June 13, 2011 – Cut and installed aluminum sheets to blend fuselage to nose cone. Made lexan plate for transponder antenna and installed. Filed top wing ribs and drilled holes for fabric rivets. Installed transponder, radio and intercom onto instrument panel. Installed Tiny Tach onto instrument panel and ran wire to engine compartment. 6 hours.
The sheet metal blends the flat side of the fuselage to the rounded side of the fiberglass instrument panel.
The transponder antenna is mounted on a 5.25 inch diameter ground plane made from .020 aluminum. This is mounted on a lexan sheet fastened to the 1/2″ diameter tubes on the floor of the front cockpit. The antenna will poke through the fabric on the belly.
June 14, 2011 – Began work on top of left wing. Installed wing tip and wing root boxes with webbing. Began installing wing ribs and leading edge wrap. This picture is shown looking from the wing tip. Must be careful not to build two right wings! 8-1/2 hours.
June 15, 2011 – Finished installing the wing ribs and riveted. Installed the webbing around the fuel tank and riveted. Installed the stiffeners behind the leading edge wrap and riveted. Temporarily installed the fuel tank in order to fit the wrap. Fitted, cut and clecoed leading edge wrap around fuel tank. Drilled holes and installed grommets and wire holders for fuel line, strobe light wiring, and wiring for fuel level sender. Ran the strobe light wires from the wing root to the wing tip. 8 hours.
The larger leading edge wrap in front of the fuel tank.
June 16, 2011 – Installed stiffener tubes behind the large sheet metal wrap in front of the fuel tank, drilled and clecoed them. Installed the fiberglass wing tip with clecoes. Installed the strobe light on to the fiberglass wing tip and wired it up. 3 hours.
June 17, 2011 – Riveted fiberglass wing tip to wing. Installed fuel line outlet fitting, fuel cap, and fuel level sender. Connected up fuel line to outlet fitting. Wired up fuel level sender. Installed angle support behind fuel tank. 4 hours.
Hangar cat inspects workmanship on left wing tip.
Another hangar cat casts a critical eye through the cockpit. Yes – they are two different cats. And yes they are both a little over weight and quite sensitive about it, so don’t say anything.
Okay – back to the serious stuff: June 20, 2011 – ordered the paint supplies from Lois at Aeromart
June 28, 2011 – Removed the tail from the fuselage and disassembled all the tail pieces. Filed off the sharp edges on the gussets on the tail. Pounded the gussets over where possible to conform more to the round shape of the tubes on the edges of the tail pieces. Sanded the aluminum tubes so that the glue will stick better to the aluminum tubes. Hung the tail pieces up in the shop, ready for covering. Made 2 sheet metal plates for the rudder travel limit to strike. Sanded and primed some of the small aluminum brackets – the elevator and rudder horns, the throttle mounting plates, and the tail strut attachment brackets. 7 hours.
The aluminum parts must be primed before they are painted or the paint will peel off in a short time. Aluminum does not like paint for some reason. I paint small aluminum parts with Tremclad metal paint from the hardware store. But first a coat of galvanized metal primer is sprayed on to prepare the aluminum surface for the colour coat of paint. I use Tremclad because they have a better quality of paint and the spray can has a better quality of nozzle that does not spit gobs of paint on to your surface. Cheaper brands just frustrate the painter.
June 29, 2011 – Sanded and primed more small metal parts including the doors. Started masking the fuselage to get it ready for covering. 3 hours.
June 30, 2011 – Spray painted the blue metal parts including the door frames and throttle mounting plates. 2 hours
July 1, 2011 – Painted small and large aluminum pieces the second coat. 2 hours
200 hours total labour so far.
July 4, 2011 – Drilled holes in the side rails and fuselage gussets for fabric rivets to help hold down the velcro strips that will in turn hold the upholstery in place. Installed the pitot tube. Drilled holes in the control sticks for the wires going to the push to talk switches. 2 hours
July 6,2011 – Removed the nose cone and installed the push pull control cable for the heater box. Made and installed a hot air control flap and connected it to the push pull wire. Installed adhesive Velcro strips to the cockpit and riveted them down with wide head fabric rivets. Ran the wires for the Push to Talk switches. Installed a bracket to hold the fuel filter and connected the filter and the primer lines. Safety wired the aileron cables and lubricated the aileron swivel joints. Received the paint supply shipment and un-boxed everything. Added the anti-chafe tape to the tail pieces. 8 hours.
July 7, 2011 – Installed bracket to hold fuel system quick connectors behind luggage compartment and finished tubing up the fuel lines. Made up brackets for the intercom plug receptacles and installed them in both cockpits. Drilled holes for the throttle and choke cables in the fire wall and installed rubber grommets. Made and installed a bracket to hold the throttle and choke cable splitters. Mounted the throttle splitter and ran the cables through the fuselage gussets. Began to cover the tail section with fabric. Covered rudder, fin and dorsal fin and ironed first step (to 250 degrees). 7-1/2 hours.
The fuel system mounted and tubed up – the two quick connectors will go to the wing tanks lines. The tee fitting runs down to the filter and then tees off to the smaller primer line before going forward to the fuel shut off valve in the cockpit. The tee fitting is strapped down to an aluminum L bracket with 4 zip ties and is prevented from vibrating with a layer of adhesive foam.
The throttle and choke cable splitter is mounted on a bracket behind the fuselage storage bay just below the fuel filter and will run from there through the firewall to the carburetors on the engine.
July 10,2011 – Covered the horizontal stabilizers and elevators with fabric, glued and ironed to 250 degrees. 3 hours.
The fabric for the tail pieces comes in pre-sewn socks that slide over the aluminum tube frame work of the tail sections. This sock is a little loose but the ironing shrinks the fabric and tightens up the fit. The sock is supplied “in side out”, so you have to reverse that. Make sure the hem goes all to one side of the seam when installed for a nicer appearance. In this picture you can see that the stabilizer in the back ground is not yet ironed and is still baggy, but the one in the fore ground has been ironed and is tight.
July 11, 2011 – Calibrated the iron for 300 and 350 degrees. Ironed all the tail section pieces to 300 degrees and 350 degrees. Used a hot knife to poke out all the drilled holes that the fabric covered. Then riveted the hinge pieces onto the tail sections and joined the complementing tail pieces together with 10-32 bolts so that the they are held stiff for ease of painting. Sanded the fuselage tubes and started masking it with anti-chafe tape. 4 hours
The fin and rudder covered and joined together with the hinges.
The iron being calibrated with a Winter’s Thermogauge analogue dial thermometer. The dial on the iron is marked for 250, 300 and 350 degrees F. These settings change over time so check the calibration frequently. The iron must have at least 1200 watts of power to maintain this heat output. many modern irons do not have this power output for reasons of “safety”.
July 12, 2011 – Finished applying anti-chafe taping to the fuselage. Assembled rotating stands. Removed the battery and drilled a 1/4″ hole in the frame for a 1/4″ bolt. Mounted the fuselage on the rotating platform and covered the belly and right side and ironed to 250, 300 and 350 degrees. 8 hours.
Mounting the fuselage on a pivoting mount makes working on the belly much easier. The pivot stands are made from 2×4’s and the pivots are 1/4″ diameter screws. One goes through the 1/4″ hole in the rear tail post. The other through a hole in the 1″ x 1/8″ thick aluminum angle that makes up the battery box. Here the belly fabric is hung loosely for positioning.
The fabric is first glued on and the excess material trimmed off.
The edges of the fabric are glued wrapping 3/4 of the way around the 1/2″ belly frame tubes to give holding strength.
The glue is allowed to dry for 1/2 hour and then the fabric is ironed to 250 degrees F. This tightens up the fabric removing the wrinkles. After an hour the fabric can be ironed to 300 and then 350 degrees F.
The fabric is hung on the side of the aircraft. There is lots of left over fabric that must be trimmed off.
Start the gluing process in the middle where the spine of the tail meets the engine compartment. This area has the most complex curves and must be completed first.
Then work forward to where the fabric ends about half way along the passenger compartment. I always install a 2″ wide sheet metal plate here to give the fabric a place to firmly attach. The fabric has some large wrinkles and waves due to trying to adapt the fabric to the shape of the side of the plane. Ironing will remove these as the next picture will show.
The fabric is ironed and the wrinkles and waves disappear.
The last piece on the side is a smaller piece that covers the side of the front cockpit. A much easier fit – less 3 dimensional complex curves.
July 14, 2011 – Finished covering the left side and ironed 250,300, and 350 degrees. Installed the fin and rudder onto the tail posts. Installed the dorsal fin and the sheet metal fin extension. 6 hours
The new Challenger XS-50 Light Sport Aircraft Tail. The sheet metal extension joins the main fin to the dorsal fin and completes the swept tail effect.
July 15, 2011 – Applied first coat of Poly-Brush to fuselage and tail section with brush and started applying finishing tapes to corners, edges and seams. 5 hours
July 25, 2011 – Installed Push to Talk (PTT) switches in the plastic caps for the control switches, soldered and installed into control sticks front and rear. Finished tapes along the fuselage sides and bottom corners. Started taping the tail section. 5 hours.
Fabric tapes are best installed by gluing a small area and letting it get tacky. Then fasten one end of the tape to this area and wait for it to dry a while. Then you can run the tape down the side and apply some tension to the tape without pulling it off the surface. This also makes it easier to mark the areas on the tape where you need to cut holes for bolt heads or other obstructions like the gear legs. I used 3 inch wide tapes along the sides and bottom corners of the fuselage. Two inch tapes were used on top of the cockpit side rails and over the 1/2 inch tubes at the rear of the cockpit and below the engine area.
The tail ribs get some fabric rivets to help hold the fabric to the tail surface. The ribs should be drilled with some 1/8″ diameter holes (best done before covering – did I mention that?). The burn the hole through the fabric with a hot knife. Then add the thin masking tape that comes with the kit. Open the holes through this tape with an exacto knife. Pop in some of the aluminum rivets with the extra wide flanges heads. Then cover these with the 2″ fabric tape.
July 26, 2011 – Finished taping tail. Masked more of the fuselage. 6 hours.
We are approaching the 250 hours of labour mark on this build. 249 hours to this point.
To tape the leading edges on curved surfaces like the tail section it is best to glue the center of the tape to the leading edge and then use the iron to make the tape conform to the curves. Another idea is to mark the center line of the tape lightly with a pencil to ensure the tape is applied on the center of the edge tube.
July 28, 2011 – Riveted lexan doors onto door frames and stored them away safe. Finally finished masking the fuselage. Start by removing the top portion of protection film and cleco the sheet to the top of the frame with the hinges on the outside of the lexan. Then remove the rest of the film and cleco the sheet to the frame. Now rivet the lexan to the frame. Use only aluminum rivets here. 5 hours.
The lexan sheets installed. Now to put them away and wrap them so they do not get scratched.
July 29, 2011 – Did some touch ups with the iron to fold down pinked edges and clear up any glue blobs. Sprayed a cross coat of Poly Brush on the fuselage and tail pieces. The picture shows the horizontal stabilizer and elevator having tape applied to trailing edge from previous day. 3 hours.
July 31, 2011 – Sprayed a second coat of Poly Brush and then cleaned the paint spray gun. Refilled the little inline desiccant dryer. The Poly Brush goes on with a semi gloss sheen when spray and the pink colour deepens. 3 hours.
August 1, 2011 – Sprayed the first coat of Poly Spray UV primer on the fuselage and tail. You can still see some pink Poly Brush peeking through. Cleaned spray gun. Refilled desiccant dryer. 2-1/2 hours.
August 2, 2011 – Sprayed the second and third coat of Poly Spray UV primer on the fuselage and tail. Sanded the finish after the second coat. Cleaned spray gun. Refilled desiccant dryer twice. Ordered larger desiccant dryer. These little inline models just don’t cut it. 4-1/2 hours.
August 3, 2011 – Sprayed two cross coats of blue Poly Tone paint on the fuselage and one cross coat of white on the horizontal stabilizers. 6-1/2 hours.
The single cross coat of white will be covered in a couple of cross coats of yellow. The white base will make the yellow final coat brighter. This is recommended by Poly Fiber when painting reds and yellows. It makes sense when you see the dull gray primer that the paint must cover.
August 4, 2011 – Final cross coat of blue paint on the fuselage. Then cleaned paint spray gun. 2-1/2 hours.
August 5, 2011 – Two cross coats of yellow on the horizontal stabilizers. Added fuel to left wing fuel tank to test tank fuel line fitting for integrity – no leaks! Yeay! De-masked the fuselage. 5-1/2 hours.
August 7, 2011 – Finished left wing – installed short rib over fuel tank and riveted the leading edge wrap in front of the fuel tank. Sized and cut the aileron to length and installed the aileron with clecoes. Cut access holes in wing root to access the fuel line for future maintenance and replacement. Installed a plate in the wing root for the wing to pivot on for the covering and painting process. Drilled a 1/4″ pivot hole in the wing tip for same purpose. Drilled the angle brackets for the motor mounts. 4-1/2 hours
August 8, 2011 – Mounted the left wing on pivots. Cleaned the left wing with MEK and sanded the aluminum to prepare it for the glue. Covered the left wing – bottom first, then top. Installed drain grommets and inspection rings (for the fuel line and tank drain fitting). Brushed on the first coat of Poly Brush. 9-1/2 hours In the picture the fabric is laid out on the bottom of the wing. The corners have been cut out so it hangs centered on the wing. Next the edges will be glued.
Start by gluing the leading edge of the wing – about mid span and work from there to the tip and root keeping the fabric smooth on the leading edge and square on the wing. Then do the other sides. Trim the excess fabric with pinking shears. Be sure to keep your trim line straight especially on the leading edge as it will be seen. Running a straight pencil line will help to keep this cut line straight and neat.
Glue down the trimmed edges of the fabric. Now iron the fabric first at 250, then 300, finally at 350 degrees F.
The wing is rotated top side up and the covering process is repeated. Hang the fabric. Star gluing on the middle of the leading edge.
Glue the remaining edges. Don’t glue all of the wing box. Just the outer 1-1/2″ is plenty. Trim the edges and glue them down. Iron in 3 stages – 250, 300. 350 degrees. Then run a thin line of glue down the 1/2″ ribs. Use a hot knife to poke the rivet holes through the fabric into the ribs.
Run the 1/2″ masking tap included with the kit over the back of the ribs and poke the holes through again. Now install the large flanged head fabric rivets into the holes and pop the rivets in. Here is where a pneumatic rivet gun saves time and energy!
We installed two inspection rings on the bottom of the wing. One to the rear of the tank where the fuel line exits the tank. The second where the fuel line passes through the rib webbing at the side of the fuel tank. These inspection holes will come in handy in checking the condition of the fuel lines and in about 5 years when the fuel lines may need replacing. Drain grommets where installed near the rear spar on the bottom of the wing in three places spaced evenly along the span.
Then the wing was brushed with Poly Brush to seal the weave of the fabric.
August 9, 2011 – Cleaned, snaded and covered aileron for left wing. Ironed it 250, 300 and 350 degrees F. Brushed on first coat of Poly Brush and riveted its hinges to the wing. Applied reinforcing tapes to the tops of the ribs and to the leading edge of the wing and the trailing edge of the aileron. Installed 3″ tape as a gap seal between the aileron and the wing. Installed fabric patches around the inspection rings on the bottom of the wing and around the area where the lift strut brackets will penetrate the wings. Drilled the 32 holes for the screws that hold the 8 rubber vibration mounts in the motor mount plate. Sanded the motor mount brackets in preparation for priming and painting. 8 hours
We just passed the 300 hours of labour mark on the build. We are now at 303-1/2 hours of labour.
The aileron (flaperon) gap is sealed with 3″ tape. The tape must be pushed down into the gap so that when the aileron moves down there is plenty of fabric to allow the full movement of the control surface.
Four inch wide tape is applied the the leading edge of the wing. To get a nice straight line on the tape edge draw a line with a pencil using a long straight edge (such as an 8 foot piece of aluminum angle) or snap a chalk line. This is the only time you can use a pencil in Challenger construction. Only use a pencil on the fabric, never on the metal. use a Sharpie marker for marking up the metal pieces.
A length of 4 inch fabric tape blends the wing to the fiberglass wingtip. It also covers all the rivets in the sheet metal box and the fiberglass. Again mark a line to get a nice straight edge on the tape. Be careful if you need to iron down any lifted edges or it will shrink the fabric and make your edge go snakey.
8 inch round fabric patches are installed over the inspection rings on the bottom of the wing. Later we will cut a 2 inch round hole, slot it and fold back the leaves on the inside of the patch and glue them down.
8 inch long x5 inch wide rectangular reinforcing patches are placed where 2 small holes must be cut for installing the lift strut brackets on the underside of the wing. We will cut the holes later when painting is finished. These patches are all made from left over fabric from the wings and the fuselage fabric pieces. There is always lots left over.
August 11, 2011 – Primed the motor mounting parts and painted them later in the day. Cleaned and sanded the metal on the right wing in preparation for gluing the fabric. Added the anti-chafing tape over the sharp edges. Tested the fuel tank by adding 40 liters of gas – no leaks. Then drained the tank. Installed 1/4″ holes in tip and wing root for mounting to wing pivot stands. Cut fuel line inspection holes in the wing root box webbing. 3 hours.
August 12, 2011 – Painted motor mount brackets yellow. Sanded and cleaned bottom of right wing and added anti chafe tape. Installed small brackets to prevent bottom ribs from vibrating against the compression struts. Covered the wing top and bottom, trimmed and ironed fabric to 250, 300 and 350 degrees. Installed fabric rivets to the top of the wing. Covered the aileron and ironed to 250 degrees. 7-1/2 hours
Rob applying the 1/2″ wide tape over the rivet holes on the top of the wing ribs. The holes will need to be opened up using a hot knife and a sharp pointy exacto knife. This tape protects the fabric from rubbing against the rivet heads.
Sonia rivets the fabric to the top of the ribs with wide head aluminum rivets. Using a pneumatic rivet gun makes the task fast and easy. There were 126 of these fabric rivets per wing.
Rob gluing the fabric to the second side of the aileron.
August 14, 2011 – Ironed aileron 300 and 350 degrees and installed onto wing. Brushed wing with Poly Brush. Installed fabric reinforcing tapes over ribs, on leading and trailing edges and as gap seal between aileron and wing. Installed inspection rings for fuel tank lines and reinforcing patches for lift strut openings. The wings are now ready for the spraying process. 5 hours.
August 15, 2011 – Cleaned up the shop in preparation for a lot of paint spraying. Swept and vacuumed the floors. Sprayed second cross coat of Poly Brush and first coat of Poly Spray UV primer on both wings. 7 hours.
The first cross coat of Poly Spray UV primer is applied. You can still see a bit of the red Poly Brush peaking through in places. This will be completely covered by the second and third coats.
August 16, 2011 – Sprayed 2 more cross coats of Poly Spray primer on the wings. Sanded between 2nd and 3rd coat. No pink showing through anymore. Sanded the nose cone, the wheel pants, and the 3 mid wing gap cover pieces. The wheel pants needed some Bondo to fill the crevices in the fiberglass in the line down the middle. 5-1/2 hours.
The wheel pants after sanding and some application of Bondo. They will need to be sanded again.
The nose cone after sanding and masking for primer paint. The fiberglass flange is masked so that paint will not affect its fit. The pitot tube is also masked off.
August 17, 2011 – Sprayed a light cross coat of white paint on the wings. Sanded the Bondo that filled the crevices in the fiberglass wheel pants. Sprayed the nose cone and the mid wing gap cover with primer. Installed the rubber vibration mounts onto the engine mounting plate. Installed the motor mount plate and a mounting angles to the engine. 6 hours.
This coat of white will help cover the dark gray primer and will make the final yellow colour much brighter.
August 18, 2011 – Sprayed a second light coat of white to further cover the gray primer on the wings. Sprayed a first coat of yellow paint to the wings. Primed and painted the strut brackets. Painted the fire wall yellow. Installed the battery in the nose. Installed the lift strut Rony brackets to the fuselage using the new high load kit. I filed and sanded the corners of the special moon shaped flange in the high load kit so the corners would not cut into the fabric. Installed the rudder travel limit strike plates. Installed the engine to the root tube. Cut and sanded the stainless steel plates for the aircraft data plates. 8 hours
The high load kit shown installed on a lift strut Rony bracket. The edges and corners of the silver C shaped flange under the black Rony bracket needed to be filed round to prevent damaging the fabric.
August 19, 2011 – Sprayed 2nd and 3rd coat of yellow paint on the wings. Installed the doors and the seat cushions. Put black plastic edging on the door lexan edges. Installed the carburetors and connected them to the throttle and choke control cables. Installed the filter. Installed the spark plug and connected the CHT wires. Took the aircraft data plates to the engraver. Ordered the vinyl striping and registration lettering. 8-1/2 hours
The black plastic door edging protects the paint and fabric from the sharp edges of the door lexan.
Just passed the 350 hour mark. Now at 354 hours total labour.
August 20,2011 – Mounted fuel pump and connected fuel lines and vacuum pulse line. Installed muffler and EGT sensors. 2-1/2 hours.
August 21, 2011 – Connected up the engine wires and oil injector cable to the oil pump. 1 hour.
August 29, 2011 – Installed re-drive tower, propeller, and starter motor. Safety wired the muffler springs and added hi temp silicone to muffler springs. Tensioned the redrive belt. 5 hours.
The muffler springs must be safety wired and the wire and spring bonded with hi temperature silicone caulking. The new style starter motor is shown here.
August 30, 2011 – Installed rudder travel stops and connected rudder cables and safety wired. Installed the horizontal stabilizer elevator assemblies and connected the elevator push rods. Installed the oil reservoir on the root tube above the engine. 6 hours.
The rudder stops installed on the top side of the rudder horns. They strike a pair of delrin bumpers bolted to the fin. Here we have provided plates for the bumpers to mount on.
The oil injection tank installed on the root tube above the engine shown from the right side. This will be covered by the rearmost section of the mid wing gap cover.
The oil injection tank installed on the root tube above the engine shown from the left side.The oil line extends from the bottom rear of the tank diagonally down and forward to the oil injection pump mounted at the front of the engine.
August 31, 2011 – Cut holes in wing fabric for lift strut brackets and inspection holes. Installed lift strut brackets to wings. Painted the nose cone and mid wing gap covers 2 coats. Lubricated all the hinges, pivots and spherical rods eyes on the fuselage with LPS-3. 6 hours.
September 2, 2011 – Soldered the headphone and microphone jacks and wired up the intercom. 3 hours.
September 5, 2011 – Cut and trial fitted the wheel pants. Installed door lock brackets. Installed the nose cone. Loaded the plane on a trailer and took it to the Kingston airport. Installed the wings. 8 hours plus 4 hours help from a friend.
Backing the trailer into the hangar with all the other planes.
The fuselage looking forlorn without plumage.
With only one wing – makes for a funny picture.
Both wings on. Will finish the install tomorrow.
Sept 6, 2011 – Assembled and installed jury struts. Assembled and installed aileron push rods. Cut wind screen. Installed door open latches. Installed aircraft data plates. 8 hours.
Sept 8, 2011 – Installed front wind screen and front section of the mid wing gap cover. Installed the front throttle / choke quadrant. 6 hours.
Just passed the 400 hour total assembly time mark. Now at 403.5 hours
Sept 10, 2011 – Installed rear throttle quadrant. Checked empennage and wing attach bolts. 3 hours
Sept 12, 2011 – Aircraft inspected by Steve Busby and passed. Set the throttles and balanced the carbs. Installed door closed latches. Removed aileron push rods and painted them. Set the elevators travel 3/4″ apart. Did a bunch of paperwork. 9 hours.
Sept 13, 2011 – Installed vinyl graphics. Submitted paperwork to Transport Canada. 8 hours.
And the tail feathers with some colourful plumage.
Sept 13, 2011 – Finished wing tip graphics. Cut and installed mid wing gap covers. Adjusted ailerons and flap settings. 5 hours.
Sept 14, 2011 – Finished installing wing tip graphics and finished install of fiberglass mid wing gap cover pieces with threaded inserts. 3 hours.
Sept 21, 2011 – Removed and re-installed muffler for better alignment. Bent the muffler mounting bracket upward about 8 degrees to accomplish this. Made upholstery pattern. 3 hours.
Sept 24, 2011 – Primed wheel pants, gear leg covers and strut and jury strut streamlining covers. 1 hour
Sept 27, 2011 – Spray painted wheel pants and streamlined leg and jury strut covers.
Sept 30, 2011 – Cut strut covers and took to airport. 2 hours
Oct 3, 2011 – Cut and marked upholstery patterns. Installed strut streamlined covers and tie down rings. 3 hours.
Oct 5, 2011 – Cut and installed streamlined jury strut covers and tail strut covers. Installed landing light. 2 hours
Oct 10, 2011 – Began wheel pant installation – required more cutting and a trip back to the shop. Nose wheel pant did not fit – the fork would not reach down to the shaft hole. The pant bottomed out on the top of the fork before it could fit right. NOTE: drill the shaft hole for the nose wheel pant 5/8″ below the dimple in the fiberglass. I had to make an aluminum flange to correct this issue as I had cut the pant to allow access to the tire inflation valve. The main wheel mounting bracket for the pants puts the mounting hole right where the tire is widest. This makes it very difficult to install the nut inside the pant. I recommend moving that hole inboard about 1.5 inches. 4 hours
Oct 11, 2011 – Completed wheel pant installation. 1 hour.
Nov 14, 2011 – Received Certification of Registration from Transport Canada! C-IMBJ is now an approved registered advanced ultralight aircraft.
Nov 17, 2011 – Filled tanks with 12 liters of pre-mixed fuel and started engine. This enables the oil injection pump to safely fill the small injection lines and expel the air bubbles without damaging the engine. After about 20 minutes of running, the fuel tanks were filled with 50 litres of un mixed fuel. Did engine break-in procedure as per Rotax Installation manual page 21-1. Engine runs beautiful.
NOTE: With wing tanks the fuel is above the engine and exerts a constant pressure on the fuel pump and actually passes through the pump. So if the fuel ON/OFF valve is left open, the carburetors will flood and fuel will drip from them. And worst of all, the engine will be very difficult to start. I learned that the hard way! Lesson: Turn the fuel valve ON when you are ready to start the engine and turn it OFF as soon as the engine shuts down. Put it on your knee board Start Up and Shut Down check lists.
Nov 18, 2011 – Bev took delivery of her new airplane. It was too windy for the test flight so we did some ground schooling / aircraft familiarization and rolled the plane back into the hangar.
Nov 22, 2011 – The test flight! The plane flew great. It was cold but the winds were calm. Read all about the performance and handling here: XS-50 Flight Test. (scroll to the bottom of the page)

on the photos for a larger view.

March 4, 2011 – Ordered Flip Up Nose Cone Hinge from