A couple of months ago Dave Royds (MrFlash) designed and built a full fuse EPP biplane for indoor pattern/3D flying based on a smaller mono he’d designed earlier. On its first outing it attracted the attention of the UK modelling press due to its clean lines and great flying characteristics. An all EPP construction and low wing loading made for a very slow flying model which was more durable than an equivalent depron airframe.

Having seen photos and video of the biplane, I decided I had to build one! Flash kindly sent me detailed photos of his model along with drawings of the fuse, wing and tail profiles. Over the past months Flash has tweaked the design slightly to improve performance, and with numerous PM’s and ideas passed forwards and backwards regarding the build process I have drawn plans for the model and tried to document the build process as best I can.

Both models (amazingly) came out with identical C.O.G’s, and AUW’s within a few grams of each other.

Specs :

Wingspan : 32”
Length : 34”
AUW : 8.3oz (including 2S400 lipo @ 25g)

Setup:

Motor : AXI 2204/54 Goldline
Prop : GWS 9050 HD
Servos : 1x HS-55 (ailerons) 2x Bluebird 306 (rudder/elevator)
Rx : Jeti REX4 MPD (35Mhz for UK use)
Esc : Castle Creations TB9

Plans :

Full Sheet A0 Plans here (568kb)

19 Page Tiled A4 Plans here (437kb)

19 Page Tiled 8.5"x11" (Letter) Plans here (502kb)

Videos :

MrFlash indoor video here :
http://www.rcgroups.com/forums/showa...mentid=1108973

Firetrappe indoor video here :
http://www.rcgroups.com/forums/showa...mentid=1093689

Simulator Downloads:

Infineon for Aerofly / Aerofly Pro Deluxe
Infineon (beta) for FMS

Mini Infineon

Specs:

Wingspan : 26”
Length : 27”
AUW : 7oz (including 3S 300 lipo @ 32g)

Setup:

Motor : Komodo 257 17T
Prop : GWS 8040 HD
Servos : 1x Blue Bird 306 (ailerons) 2x Blue Arrow 4.3 (rudder/elevator)
Rx : MZK Penta 3g (35Mhz for UK use)
Esc : Castle Creations TB9

Plans :

Full Sheet A1 Plans here (126kb)

16 Page Tiled A4 Plans here (629kb)

16 Page Tiled 8.5"x11" (Letter) Plans here (674kb)

Video :

Firetrappe outdoor video here :
http://www.rcgroups.com/forums/showa...mentid=1165087

i3D (New outdoor 3D version)

Plans :

Full Sheet A1 Plans here (445kb)
25 Page Tiled 8.5"x11" (Letter) Plans here (403kb)

Build Guide In PDF format (thanks to RdJay) : http://www.rcgroups.com/forums/showa...mentid=1468779

Infi Photo Gallery (thanks to DaOldGuy) : http://www.rcgroups.com/forums/showthread.php?t=947767

Infineon Owners Club Map : http://maps.google.co.uk/maps/ms?hl=...mid=1226524445
(Please add your location to the map if you build one).

If using the tiled plans then tape the sheets carefully together making sure that they line up perfectly. Once I had the plan assembled I cut the plan down into smaller areas (ie. Wing, tailplane, fus etc) and used double-sided tape to temporarily stick them to the EPP sheets so that they didn’t move while I cut parts out. Most of the cuts can be made using a straightedge (ruler) and the more accurate the cuts are to 90°, the easier it will be to build nice and straight.

For parts that needed producing in multiples (ie. Wings, fuselage sides and formers) I was able to remove the paper from the cut parts, leaving the double-sided tape attached to the paper, and then re-use the templates again.

Once all the parts are cut I recommend doing a ‘test fit’ as seen below to make sure that all the pieces fit in their respective slots. Any slots that need enlarging are better done now rather than when covered in glue!

Notes:
The plans are drawn assuming 9mm EPP is used for the centre cabane, although 2 pieces of 5 or 6mm could be used instead. I cut the servo holes at this point however, plans are drawn assuming a Hitec HS-55 is used for ailerons and 2x Blue Bird 306’s are used for rudder/elevator.

Next, the trailing edges of the wings, horizontal and vertical stabs need the bevels cut/sanded to 45°. I used a steel rule and the edge of my cutting mat as guides and cut the bevels using a sharp blade. While I was in ‘bevel mode’ I also cut the bevels on the rudder, elevator and ailerons.

The carbon fibre can now be glued to the areas shown in the photo below. 0.5mm x 3mm strip was used for all areas except the centre cabane. I applied contact adhesive to the foam and the cf, allowed it to go tacky and then stuck the two together. The cf was taped to the wing to hold it in place while drying. The cabane used a 2mm CF rod which I sharpened to a point on one end and then pushed through the foam (rotating the rod at the same time) to embed it. The point was left exposed by about 2mm to aid alignment of the upper wing during final assembly.

Slots were cut in the outer struts and reinforced with 0.5mm x 3mm CF strips.

Note :
The photo shows the CF rod exposed on the bottom of the cabane. This needs to be cut off flush before gluing in place. Also, the cf on the leading edges is in 3 pieces, the main centre section and two additional pieces for the tips.

The two firewall pieces were next glued together. Once dry, the top and bottom of the firewall were bevelled using the top and bottom spacers to work out the angles. The firewall was glued to the fus side with approximately 3° of down and right thrust built in. The centre crutch was then trimmed to match the angle of the firewall and glued in position from the firewall until it begins to taper.

Once dry, the nose was supported and the rear end of the crutch was glued into place as shown below.

The top of the fus and upper former can now be glued in, taking care to make sure everything stays nice and straight. Make sure to put some glue around the sides of the cabane cutout, I nearly forgot! This also helps the top of the fus keep its shape while drying.

Once dry, the nose can be supported again and the rear former and servo tray can be fitted. Both the tray and the former were trimmed to size (using the centre crutch as a guide) before gluing. You may want to position the servo tray further forward if you are using heavier servos to keep the weight forwards. The further forward the servos are however, the harder they will be to access once the wings are fitted.

I made a motor mount from a piece of fibreglass printed circuit board (lightweight ply would be a good alternative). Before glueing to the firewall I drilled holes for the motor shaft, wires and mounting screws. Matching holes for the shaft and wires were made in the EPP firewall.

To avoid using servo extension leads I mounted the gear as shown in the photos below. The rx was fixed to the centre crutch using velcro (the velcro in contact with the EPP was sprayed with 3M 77 to ensure it had a strong bond). This allows me to change the xtal in the rx without too much trouble.

I prefer using a velcro strap to secure my lipo’s, so I added pieces of strapping tape to both sides of the centre crutch (to avoid the foam tearing on heavy impacts!) and cut slots so that I could loop a strap over the cf. I sandwiched the esc wires between a piece of spare EPP to keep them out of the way and provide a solid base for the lipo to lie on. This also keeps the weight of the lipo as close to the thrust line as possible.

The servos were glued into the tray and then the lipo was connected to make sure they were centred (and everything worked). While I still had good access to the inside of the fus I routed a Du-Bro micro pushrod ‘snake’ through the rear former and fus. Doing this now allowed me to keep the angle of the pushrod as shallow as possible to prevent any unnecessary strain on the servo.

The second fuselage side can now be glued in place. I found it best to work from the back of the fus to make sure the horizontal stab slots lined up and work my way to the front.

While the glue dried I used Blenderm tape to hinge the ailerons, elevator and rudder using the ‘standard’ shockie method. Prior to hinging the ailerons I cut the holes for the aileron control rods to make sure the holes in the connected ailerons would be in line with each other. (see step 12 for more details)

The top of the fuselage can now be completed. I started by gluing the edges of the canopy and the edges of the top of the fuselage that needed joining. Once the glue was tacky I fitted the canopy piece starting from the front and worked my way back to the tail ensuring that the fuselage stayed straight. I then pinned the top of the fus in several places to hold everything in place while the glue dried.

Once dry, the horizontal stab/elevator and vertical stab/rudder can be glued in place. Test fit and trim/sand the slot and top of the fuselage if necessary to help keep things square. Again, pin as required while the glue dries.

The fuselage was now placed upside-down, and I installed the pushrod for the rudder. This can run parallel with the bottom of the fuselage, passing through the rear former and out through the fuselage side, again preventing undue strain on the servo.

At this point the second fus lower former was trimmed and glued into the fuselage in front of the rx. A hole is needed in this former to allow the wires from the esc and aileron servo to pass through to the rx.

I then glued the lower wing re-enforcing plate to the lower wing, making sure that it was at 90° to the hinge line and that the servo holes in both parts lined up. Once dry, the wing was glued to the fuselage.

I used Du-bro micro horns and light ply for the control horns (matching the control rods). The ply had a small hole drilled in it to allow the barb of the horn to pass through and pierce the foam. The horns and ply were glued together using epoxy and positioned inline with the previously installed pushrods. I added a blob of glue to the tip of the barb on the opposite side of the control surface to further secure the horns.
The aileron horns were positioned on a slight angle so that they were lined up with the aileron servo. It is a good idea to fit the aileron servo at this point and connect it to the rx while you have easier access. I did not glue the servo in at this point however, so that it could be removed and placed inside the lipo bay, allowing the fuselage to sit flat for fitting the upper wing.

Next the outer struts were glued into the slots on the lower wing. The upper wing was then slotted onto the struts and glued in place using the carbon protruding from the cabane to help hold the wing in position.

The landing gear was made by sandwiching 2x 2mm diameter carbon rods between the two remaining formers. I made grooves in the formers using a soldering iron and then glued in the carbon. The two formers were then glued together and left to dry with a weight compressing the two halves.

The axles were made from piano wire bent to shape as shown below. This allows the spats to be glued to the axle to add that finishing touch. The axles were then glued with epoxy and bound with to the cf rods. Notice the notch cut in the top of the formers to allow the esc wires to pass through.

I next connected the pushrods and routed the aerial wire through the rear former and out the rear of the fuselage just above the tail skid. If you are confident that you will not need access to the rear servos or rx, then the bottom of the fuselage can now be glued in.

I opted to add an access hatch below the servos. I added some extra pieces of 3mm EPP to the sides of the fuselage and cut the bottom rear spacer to create a hatch similar to the lipo bay hatch at the front.

The bottom rear spacer was then glued in place. The hatch was secured with strapping tape at the narrowest point and velcro was used at the other end to hold the hatch closed.

The landing gear and front spacer were then glued in place. Note, I bevelled the front spacer to make the front of the nose square. The lipo bay re-enforced sides were then trimmed to fit and glued in.

The lipo bay hatch was attached using 2” wide strapping tape running from the front of the front spacer to the leading edge of the lower wing. The tape was trimmed to fit around the LG struts and velcro was stuck to the overhanging tape and between the LG struts to hold the hatch closed. Lastly, the aileron servo was glued in position and the control rods connected. I used a pushrod kit identical to the set used for the rudder and elevator. The outer tubing was cut to size and slid over the thin wire rods to reduce flexing.

The upper and lower ailerons were linked using 1.5mm diameter cf rods. To secure each end of the rods you need 4x 1” lengths of rigid plastic tube with an inside diameter of 1.5mm. I found that the ink tubes from ballpoint pens were perfect! I made a hole near the end of each tube using a pin and then used the offcuts from the Du-Bro pushrods to pin each tube into the four holes in the ailerons. The four pins were glued into the ailerons, taking care not to get any glue around the tubes so that they could easily pivot on the pins. The carbon rods were then cut to fit (leaving them slightly short so that they could be adjusted in the tubes). Once I was happy that each pair of ailerons were level with the wings I glued the carbon into the tubes.

The wing braces were made from 2mm diameter cf rods. I used a length of pushrod wire I had left over from the ailerons and inserted it through the lower wing at about 45° just behind the aileron servo. The thin wire was pushed through the foam towards the outer strut. This was done a couple of times until I got the correct angle so that the wire lined up with the point where the outer strut joined the upper wing. Because very thin wire (pushrod) was used, only tiny pinholes were left where the wire had pierced the foam. The tiny holes and tunnels that the wire made were enough to be able to guide the cf rod on the correct angle first time. The photos below give you an idea of where the cf rods exited through the sides of the fuselage to create the perfect angle. The first brace was glued in place and then the same procedure was carried out for the opposite brace.

Many of the latest indoor pattern and freestyle planes use fixed airbrakes. These are used to slow the ‘downline’ speed of the model so that it is easier to perform manoeuvres keeping a constant speed. Flash has experimented with various brake ideas on the Infineon, the most effective being 40mm wide strips of 5mm EPP attached to the rear of the outer struts. I bevelled the top and bottom edges of the brakes so that they followed the curve of the outer struts and fitted flush against both wings. If intending to fly the model outdoors then it is probably better to leave the brakes off initially, they add drag and reduce the forward speed of the model significantly if flown in breezy conditions.

I designed the decals in the photo below to add a bit of character to the model without adding too much weight. The decals were inkjet printed onto 5 sheets of 11”x17” waterslide transfer paper and then attached to the model using 3M77 adhesive. For detailed instructions see my mini ‘how-to’ thread here :

http://www.rcgroups.com/forums/showthread.php?t=582939

As the majority of people don't have A3 printers I have produced pdf's for the Infineon and Mini Infineon suitable for Letter sized transfer paper. These are in a tiled format and I recommend you print them on normal paper first to check they fit your model. Once you have confirmed that they are the correct size then print them onto transfer paper one page at a time to avoid paper jams. The pdf's can also be opened in Photoshop and the colours can be changed by adjusting the hue of each page.

Infineon Blue Decals - Letter Tiled (27Mb)
Mini Infineon Purple Decals - Letter Tiled (17Mb)

Well, that’s about it…

Thanks for reading, and if you have any questions regarding the design or build then MrFlash and myself will do the best we can to answer them.

Happy Building,

Si.

Superb job as ever Firetrappe !!

hopefully get a decent video done soon with a proper pilot to show it at its full potential.

feel free to post any questions fellas