MAN contributor and prolific model airplane designer Pat Tritle has another great construction article coming. This time it is the famous British dogfighter the RAF SE5a Scout. Electric powered, this parkflyer size WW1 biplane will be in the next issue of MAN and plans will soon be available at the AirAgeStore.com website. Pat will also have laser cut parts available to speed the building process. If you longed for a taste of “Dawn Patrol” aviation, the SE5a is for you. The plans are now available for sale at: http://www.airagestore.com/s-e-5a-ww-1-scout.html
Wingspan: 36 inches
Length: 28 inches
Here is the complete, unedited text from Pat Tritle’s most recent project.
The Royal Aircraft Factory S.E.5a was first flown in November of 1916, and entered service in January 1917 after modifications to strengthen its wings were made to the third proto type to correct for weaknesses discovered in initial flight testing. The S.E.5 proved to be a very stable platform, and by squaring the wings a bit over the initial design also improved low speed handling. The S.E.5a was a better airplane then the Sopwith Camel and quickly proved itself to be easier to fly, especially by novice pilots.
The S.E.5a had much better performance then the Camel as well, but was plagued with problems from the under-developed Hispano-Suiza engine, especially the geared H-S 8B powered versions which created a shortage of S.E.5a’s until well into 1918. However, together with the Camel, the S.E.5a was instrumental in maintaining air superiority in mid 1917 and through the rest of the war.
The S.E.5 had a wingspan of 26 feet 7-inches and was 20 feet 11-inches long. Empty weight was 1,410 lb. with a gross weight 1,988 lb. Power was provided by either the Hispano-Suiza 8 or the Wolseley Viper 200 HP engine with a maximum speed of 138 mph, a range of 300 miles, and a service ceiling of 17,000 ft.
Armament included a Vickers .303 caliber forward firing machine gun firing through the prop with a Constantinesco interupter gear, and a Lewis .303 caliber machine gun adapted to the Foster mount on the upper wing. The S.E.5 could also cary 4, 25 lb. Cooper bombs, 2 on each lower wing. Though not as maneuverable as the Camel, the S.E.5 proved itself a good stable platform with excellent high altitude performance visibilty and was a worthy opponent against the Fokker D-VII upon its arrival at the front, though it was felt that in spite of its strength and fine flying qualities was a bit under-powered until it began to be replaced with the S.E.5a in 1918 until the end of the war, ultimately equipping 21 British Empire Squadrons and 2, U. S. Units.
The S.E.5 is just about the perfect platform for a small – mid-sized electric powered park flyer. With its long nose, generouse dihedral, and inherently stable flying qualities, it makes for a terrific first WW-I fighter. And with its simple all wood design incorporating straight lines with few complex curves lends itself well to the novice builder as well.
The fuselage and tail group are of the typical old school “stick frame” style of construction, while the wings are done in the more modern “egg-crate” style to speed up and greatly simplify the building procees and eliminate unecessary structure. And by using the simple centerline top wing alignment jig and lower wing tip jigs made up from artists foam board wing alignment is simple and just about fool proof. The model also incorperates functional scale rigging which aids in keeping the weight down which is what makes the S.E.5 such a gentle, though very capable flyer.
The model is set up for 400 Outrunner power on 2 LiPoly cells and is controlled with 4 channel R/C using one servo each for the rudder and elevator, and a servo in each lower wing to control the bottom wing ailerons. The top wing ailerons are slaved to the bottom using a simple link rod arrangement.
Building the S.E.5a
Before construction begins, gather up the materials called out on the parts list, then cut out all the parts using the full size patterns provided. The templates can be laid over the wood sheets and cut through the patterns, or you can make printwood from the drawings provided. Once all the parts are cut out, construction can get underway.
Begin with the vertical and horizontal tails. Lay out the assemblies over the plans using the part numbers and wood sizes shown. Once the basic assembly is completed, remove the parts from the board and sand to shape. Cut the hinge slots and dry fit the hinges, but don’t glue them in place until after the parts are covered. The hinges are 5/32 x 1/2-inch strips cut from Great Plains hinge stock. The rudder control horn is made from a round wooded toothpick cut to 1 1/4” long, centered in the rudder, but don’t glue it in until the frames have been covered.
Starting with the top wing, pin A8, A12, and A13 in place on the plans. Then dry fit the ribs R4, R5, & R6 onto the main spar A2T and pin the assembly in place over the plan. Fit the aileron hinge spar A4T in place and then tack glue each point of contact with a drop of thin Cya. Next, using the Rib Angle Gauge, align and glue rib R3 in place, followed by the leading and trailing edges. Build up the wing tips from 1/8-inch sq. balsa and parts A2 & A3 using the assembly drawing provided. Align the tip assembly with the main and aileron hinge spars and glue A2 in place against the leading edge, and A3 to the trailing edge.
Build the ailerons in place into the wing assembly. Begin by sanding the bevel into the bottom of A5 using the rib detail drawings for reference. Pin A5 in place and add the ribs AR1 & AR2, followed by A10 glued in flush with the bottom of the aileron. After both wings are completed, build up the Center Section directly over the plans. With the basic assembly completed, fit the wing panels in place and block them up 1.2-inches at the location shown. Glue the panels in place followed by the 4, A9 cabane strut doublers on A8. Now you can remove the wing assembly from the board and sand to shape. Once the wing is sanded to rough shape, cut the ailerons free and finish detail sanding the entire assembly. Cut in the hinges, but don’t glue them in until after the wing is covered.
The bottom wings build much like the top, with the exception of the servo mounts and the location of the interplane strut mounting points. Begin by pinning the SM1 servo mount plate and the main spar A1B in place on the plans. Glue R5A in place on R7 making a RH and a LH assembly, then slip ribs R4, R6, R7, and R9 in place on the spar, followed by the aileron spar A4B. Pin the 1/16 X 1/4-inch balsa trailing edge in place and tack glue each point of contact. Then moving toward the root, glue the R8A doublers in place on the R8 ribs as shown – you’ll need to make a RH and a LH assembly. Pin the rear support A16 over the plans, then using the Rib Angle Gauge, align and glue the R8 rib in place followed by A-17. Then moving back to the tip, build up the tip assembly. Align and glue the 1/4 X 3/8-inch balsa leading edge in place, followed by the tip assembly. And finally, cut the alignment dowels to length and glue them into the R8 ribs.
Next, align and glue the interplane strut hard points A14 and A15, and the servo mount braces SM2 and SM3 in place. Assemble the ailerons on the wing assembly the same as was done building the top wing, the only exception being A11 which is glued in flush with the top surface, and A6, glued flush with the bottom. Then once the glue has dried, remove the wing assembly from the board and sand to shape, Remove the aileron and finish detail sanding the parts, and finaly, cut in and dry fit the aileron hinges.
Begin by pinning B1, B4, and B5 in place over the Fuselage Frame Assembly drawing. Then add all of the remaining framing using the wood sizes shown. Build 2 frames, adding the push rod guide PRG flush with the outside edge of the RH frame assembly. Align and glue B2 and B3 in place at the locations shown, again being sure you have a LH and a RH side. Build up the cabane strut mounts from parts CM1 and CM2 and set them aside until later.
Before joining the frames, make up the landing gear mount beams as shown per the Detail Drawing. Pin the beams to the Framing Plan Top/Bottom View with the notch facing down. gently crack the longerons at Former Station 3 so that the sides angle inward toward the tail and then fit the fuselage sides over the beams. Align the sides vertically and glue in place on the LG beams. Build up the motor mount and former 1 and glue the assembly together, then glue in place onto the the front end of the fuselage frame. Add the 1/8-inch Sq. balsa crosspiece as shown just in front of B2. Add formers 2 and 3, the Cabane Strut mount assemblies, and the 1/16 X 1/8-inch balsa cross piece below former 3. Pull the tail post together, align and glue it in place followed by formers 4, 5, 6, and 7 and all of the remaining cross pieces, followed by all of the 3/32 Sq. balsa stringers to complete the basic fuselage frame.
Build up tail skid and radiator assemblies using the part numbers shown. Make up the cowl flaps from 1/16 X 1/8 balsa sanded to a triagular cross section. Glue all of the louvers in place as shown and fit the cowl assembly onto the fuselage and sand to final shape.
Setting Up the Servos:
Align the servo arms to a neutral position and glue the aileron servos onto the mount plates SM1 using silicone caulk and set aside to dry thoroughly. When dry, run in the extension leads. Then moving on to the fuselage, glue the servo mount rails and beams in place using the wood sizes shown. Mount the servos with the rudder servo on the centerline, and the elevator servo to the far RH side. Run in the Sullivan #507 plastic elevator pushrod tube and secure it on both ends and at a couple of points in between using the PRSO stand-off’s. Rig the continuous rudder pull/pull cables per the Detail Drawing provided. Tape the rudder assembly in place on the fuselage and tie the cables off at the control horn. Mark the exact location on the plans where the cables exit the fuselage for reference to be used after the model is covered.
Making Up the Wire Parts:
Patterns are provided for bending the Landing Gear and Cabane Stut components as well as the assembly drawing to build up the Landing Gear Spreader which offers some suspension in place of a rigid landing gear.
Begin by bending all of the landing gear components to shape using the provided patterns from the wire sizes shown. Tape the struts in place on the fuselage frame and solder the front and rear struts together. Slip the short section of the spreader wire into the brass tube and solder it in place. Then slip the long section into the tube and solder the assembly in place on the gear. Be careful not to inadvertently solder the long wire into the tube or the slip joint won’t work and you’ll end up with a rigid gear after all. Then after all the joints are soldered, wrap all of the junctions with fine copper wire and re-solder all the joints. Now you can add the Fairings LGF and LGR, and then remove the Landing Gear Assembly from the Fuselage and set it aside until Final Assembly.
Bend the Front Cabane Struts per the Bending Patterns and set aside. For the rear Cabanes, make only the bottom bent, then slip all four struts into the mounts and position them as shown on the fuselage side view. Now that you can visualize the compound angle at the top of the rear struts, make the bends so that the struts protrude vertically upwards so that the bends at the top of all four struts are parallel and perpendicular.
Mounting the Motor:
The firewall is set up for either the Suppo 2212 or the E-flight Park 400 Outrunner motor. Mount the motor with at least 2 screws, then set up the ESC and test the motor (without the propeller) to check for proper direction of rotation.
Covering the S.E.5a:
The model should covered with a light weight iron-on film such as Coverite Microlite, Coverlite, or Nelson Litefilm. Light Silkspan or Tissue and dope are also a good option. I covered my model with Dark Green Microlite on top and Cream on the bottom, then painted the top with Testors Model Master Field Drab enamel using a Paashe H-1 Airbrush. To prep for paint, I wiped down the entire surface with common White vinager to remove the residue left by the manufactering process. Once it’s cleaned up, handle it as little as possible so’s not to leave oily fingerprints that will effect the already marginal paint adhesion.
To begin, cover all of the frames, except, for the bottom of the fuselage. We’ll get to that in a minute. For best results, always follow the manufacturers instructions for your chosen material. Graphics for the S.E.5a are available from www.callie-graphics.com in just about any scheme you can find. Once covered, all of the hinges can be glued in place using Canopy 560 glue.
We’ll mount the bottom wing first, and everything else will align from there. To get started, cut the Bottom Wingtip Jigs and Top Wing Incidence Jig from artists foam board or plain corrogated cardboard. Feed the servo leads through the holes in the fuselage sides and plug the bottom wings into the fuselage. Locate the fuselage flat on the building board and then support the wings with the jigs placed under the outer-most ribs. Glue the wings in place with Canopy 560 glue and allow to dry thoroughly.
Slip the cabane struts into their respective mounts, then slip the top wing onto the struts supported by the Top Wing Incidence Jig. Then plug in the Interplane struts into the upper and lower wings. With the wings nice and straight, tack glue each point of contact with a drop of thin Cya. Then lift the model from the board and permanently glue each of the strut loacations.
Now you can mount the landing gear, lash it in place with heavy duty sewing thread and glue the corner gussets in place. Before the fuselage bottom is covered, reinforce the exit points for the rudder cables with a small piece of Scotch transparent tape. Align and glue the vertical and horizontal stabilizers in place and then run in the rudder cables. Once they’re tied off and adjusted, cover the bottom of the fuselage and paint as required. The elevator is connected using .025-inch diameter steel wire. It can be connected with either a Z-bend at both ends, or using a Z-Bend at the back and a Micro EZ-Connector at the servo.
To set up the ailerons, first set the servos arms to the neutral position. Make up the pushrods using .032 wire with a Z-bend at both ends. Slip the rod into the servo arm, then place the control horn onto the rod and slip it into the slot in the aileron. Align and glue the control horn in place. Then using The Aileron Link Rod detail drawing, cut 4 pieces of 1/16-inch O. D. aluminum tube, align and glue those sections into A10 and A11 using a section of .032 steel wire to keep them in line. Remove the steel alignment wire, and with the ailerons in the neutral position, cut a section of tubing to fit between the upper and lower pins, leaving a slight gap between each section of tubing, put a piece of heat shrink tubing at the top and bottom to secure the link rod in place. The last step is to rig the wings and tail section using heavy duty nylon thread. The best way to set up the rigging is to look at pictures provided, or of the full scale S.E.5a and add as much of the scale rigging as desired.
At this point the model is pretty well complete, lacking only the finer details. Mount the wheels, battery hatch cover, cowl and tail skid assemblies, then add any other desired details. The S.E.5a carried several different gun configurations from the Vickers machine gun on the cowl or the Lewis gun on the top wing, and sometimes both. We’ll leave that up to the builder using the scale gun drawings provided. And with that, your new S.E.5a is just about ready for it’s first combat mission.
Balancing and Flying:
Balance the model at the location shown using battery placement to your best advantage to accommodate CG. Using the 1320 2S Sky Lipo, the battery ended up attached to the back side of the motor mount, secured with a Hook & Loop strip. The contols were set up to the values called out on the plans and double checked for proper direction of deflection to complete the project.
Pick a calm still day for the trim flights – it’s hard to trim a new model in rough air. With the model pointed into the breeze, make one last control check, and if all is OK, push the throttle up for the first take-off. Ground handling is exceptional, even for a WWI type model, and once in the air it won’t take long to see what a gentle and docile flyer the model is. Control is crisp and relatively quick, but the S.E.5a in not twitchy. The ailerons do exhibit a bit of adverse yaw, so a touch of rudder input will fix that right up. And because of the generous scale dihedral, the model turns equally as well with the rudder alone as with the ailerons.
Landing require that you carry a bit of power. Set up a comfortable sink rate using the elevator to set up the attitude slightly nose high, then use power to control the rate of sink. Once in ground effect, the sink rate eases up a good bit, and when the mains touch down simply pull the power back and she’ll stay on the ground without any tendency to bounce back into the air. Then once you’re comfortable with how she flies, try a few scale maneuvers, and maybe even a few touch-n-go’s. From here, the only thing left is to enjoy the ride.
3- 1/16 X 3 x 36 Balsa Sheet (Shaped Parts)
1- 3/32 X 3 x 36 Balsa Sheet (Shaped Parts)
2- 1/8 X 3 x 36 Balsa Sheet (Shaped Parts)
6- 1/16 x 1/8 x 36 Balsa
2- 1/16 x 1/4 x 36 Balsa
6- 3/32 Sq. x 36 Balsa
8- 1/8 Sq x 36 Balsa
1- 1/8 x 3/16 x 12 Balsa
1- 1/8 x 1/4 x 36 Balsa
2- 1/4 x 3/8 x 36 Balsa
3/8 x 8 Triangle Stock (Scale Engine Detail)
1/2 Sq. x 8 Balsa (Scale Engine Detail)
3/4 Sq. x 12 Balsa (Headrest and Tail Fairing Block)
1- 1/32 x 2 x 6 1/2 Birch Ply (Shaped Parts)
1- 1/8 x 2 1/2 x 2 1/2 Lite Ply (Shaped Parts)
1- .025 x 18 Steel Wire (Elevator Pushrod)
1- .032 x 12 Steel Wire (Aileron Pushrods)
1- .046 x 12 Steel Wire (Landing Gear Spreader)
2- 1/16 x 36 Steel Wire (Main Landing Gear & Cabane Struts)
2- 1/16 O. D. x 12 Aluminum Tube (Aileron Link)
1- 3/32 O. D. x 12 Brass Tube (Landing Gear Spreader)
2- 1/4 O.D. x 12 Aluminum Tube (Scale Exhaust Stacks)
3” Small Heat Shrink Tubing (Aileron Link)
Heavy Duty Nylon Carpet Thread (Wing and Tail Rigging)
1 Pr.- 3” WWI Style Wheels (Kits available from http://patscustom-models.com/shortkit3.html)
1- Sullivan #507 Pushrod Tube
1- 3/16 Artists Foam Board (Assembly and Alignment Jigs)
2 Rolls- Iron-On Mylar Covering Material (1- Cream 1- Dark Green)
1 Set Scale Graphics (Available from www.callie-graphics.com)
1- .010 x 1 1/2 x 1 1/2 Clear Acetate (Windshield)
Power and Guidance;
1- Suppo 2212/13T or E-Flite 920KV Park 400 Outrunner Motor
1- 18 – 20A ESC w/ BEC
1- APC 9-6 SF Propeller
1- 1320 mah 2S Sky Lipo Battery
1- Deans Ultra Pin Battery Connector
4- 8 Gram Sub-Micro Servos
2- 6” – 9” Servo Extension Leads
1- 4 Ch. Radio (Minimum)
SEca 1- The horizontal stabilizer is built directly over the plans, then lifted from the board, sanded to shape and the hinges cut in and dry fitted.
SEca 2- The vertical stabilizer is built directly over the plans, then lifted from the board, sanded to shape and the hinges cut in and dry fitted.
SEca 3- The top wing panels are framed up over the plans beginning by dry assembling the interlocking spars and ribs.
SEca 4- The bottom wing is assembled over the plans with the only major difference between the top and bottom wing panels being the servo mount.
SEca 5- The bottom wings are completed with the addition of the leading and trailing edges and tip assemblies. The ailerons are built into the wing structure, then removed for the final sanding and shaping.
SEca 6- The front fuselage former and motor mount are assembled first, then glued in place on the fuselage frame as a completed assembly.
SEca 7- The firewall is marked with mounting holes for both the Suppo and the E-Flite 400 class outrunner motors.
SEca 8- The fuselage sides are cracked at former station 3 and the tail post pulled together. Machinists squares are used to insure proper alignment for gluing.
SEca 9- Fuselage assembly begins with setting the side frames on the landing gear beams and then gluing the front former and motor mount assembly in place.
SEca 10- Fuselage assembly begins with setting the side frames on the landing gear beams and then gluing the front former and motor mount assembly in place.
SEca 11- The Fuselage is completed with the addition of all the formers, cross pieces, stringers cabane mounts and tail skid mount assembly.
SEca 12- The Fuselage is completed with the addition of all the formers, cross pieces, stringers cabane mounts and tail skid mount assembly.
SEca 13- The tail fairing block is cut from soft balsa and glued in place with the final shaping and sanding done on the fuselage frame.
SEca 14- The radiator assembly is built up from balsa and sanded to shape. After the final sanding is done, the radiator louvers can be added. The radiator can be either tack glued in place or retained with magnets during final assembly.
SEca 15- The servos are installed on balsa beams in the cockpit area for easy access. The rudder servo is mounted on center to accommodate the pull/pull cable system.
SEca 16- The servos are installed on balsa beams in the cockpit area for easy access. The rudder servo is mounted on center to accomodate the pull/pull cable system. The cockpit fairing was made from file folder paper and glued in place after the servos were mounted.
SEca 17- The elevator pushrod is made up from a plastic tube housing a .025 steel wire pushrod. The tube is supported along its span to prevent the pushrod from buckling under load.
SEca 18- The Suppo 2212 outrunner motor is mounted in the motor box with the ESC positioned in the top former cut-outs to prevent interference with the battery in the somewhat limited space available.
SEca 19- With all the framing, shaping and sanding done the S.E.5 is assembled to check for any remaining fit problems before the model is covered. Fixing small problems now is easier the correcting big problems after the model is covered.
SEca 20- The Top Wing Alignment jig is used to align the top wing during final assembly. The jig was revised after the model was built to make it easier to set up.
SEca 21- The struts and landing gear fairings were stained, and along with the radiator assembly were given 3 coats of Polyurethane varnish to seal the wood.
SEca 22- All of the major assemblies were stripped down and given a final detail sanding in preparation for cover.
SEca 23- All of the frames were covered with Coverite Microlite. The surface was cleaned with white vinagar to remove any residue left by the manufacturing process and painted with Model Master enamel.
SEca 24- The vinyl graphics from Callie-Graphics were added to complete the basic color scheme. The graphics are not accurate to any particular squadron, but are representative of the type markings of that era.
SEca 25- The ailerons are connected with a .032 steel wire pushrod. To eliminate the added weight of standard hardware, a Z-bend is used at both ends.
SEca 26- A home-made jigging system is used to rig the wings during final assembly. A simple jigging system is included on the plans that will insure the wings go on straight and true.
SEca 27- The cabane struts are slipped into their respective mounts with the balsa fairings in place. To make access easier, the scale engine details and gun site were added before the top wing was glued in place.
SEca 28- The top wing is slipped onto the cabane and interplane struts, aligned and tack glued. Then once in place, each of the joints are permanently glued in place.
SEca 29- The scale gun site was made up from aluminum tube and glued in place on the fuselage before the top wing is permanently mounted.
SEca 30- The wing rigging is added using heavy duty nylon carpet thread. The rigging is functional, so it’s not a good idea to omit it unless there’s no plan to perform any aerobatic maneuvers. Use the photo as a guide to rig your model.
SEca 31- The wing rigging is added using heavy duty nylon carpet thread. The rigging is functional, so it’s not a good idea to omit it unless there’s no plan to perform any aerobatic maneuvers. Use the photo as a guide to rig your model.
SEca 32- The wing rigging is added using heavy duty nylon carpet thread. The rigging is functional, so it’s not a good idea to omit it unless there’s no plan to perform any aerobatic maneuvers. Use the photo as a guide to rig your model.
SEca 33- The tail section rigging is set up per the full size S.E.5 using nylon carpet thread. The rigging is functional, so don’t leave it off. The photos can be used as a guide to set it up.
SEca 34- The tail section rigging is set up per the full size S.E.5 using nylon carpet thread. The rigging is functional, so don’t leave it off. The photos can be used as a guide to set it up.
SEca 35, 36, 37, 38- Static shots of the S.E.5 just after the maiden flight.
SEca 39, 40, 41, 42, 43- Inflight shots of the model on the maiden flight.
In flight, the S.E.5 is a very docile and stable flyer, but is also capable of all the scale maneuvers the full size airplane would do.