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Apr 20, 2008, 06:16 PM
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Build Log

1/10 Semi-Scale EPP Mini Cassutt – Free Plans, Build Guide & Video

I've not done a build guide for a while, and I thought a few of you might be interested in my latest EPP scratchbuild. Some of you know that I follow the Japanese scene quite closely, which is reflected in a lot of my models. This one is no exception. The Mini Cassutt was designed in February this year by Mr. Katsuhiko Toba, it was such a nice looking model and flew so well that Toba's templates were converted to PDF plans by Mr. Shinichi Kurita and made available on the YSFC (Yakota Slow Flyer Club) website ( Build instructions to accompany the plans were written by Toba and published on his website shortly after ( to explain the construction techniques involved.

To build the model I had to translate the plans and build instructions into English. Mr. Toba and Mr. Kurita have kindly agreed to let me post the translated plans and instructions here on RCG so that we can all share the design.

The model is made from 3mm and 5mm EPP, and although the model may look complicated it is a fairly easy build.

I decided to paint mine in the scheme of ‘G-BOMB’ a UK Cassutt owned by Richard Grace (son of famous Spitfire pilot Carolyn Grace). I painted parts of the model as I built it rather than masking it once I’d finished, so I’ll add details of when this was done during the guide.

Specs :

Wingspan : 18”
Length : 20”
AUW : 102g

Motor : 1811-2000kv 10g Outrunner
Esc : XQControl XP-7A (Pentium 6A alternative)
Rx : Spektrum AR6300
Battery : 2S250 Fullriver Lipo
Servos : Arced D531BB (A,E,R) – Digital equivalent of standard 3.7g servos.
Prop : GWS 6030DD

(3 min 9 sec)
Last edited by firetrappe; May 12, 2008 at 08:59 AM.
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Apr 20, 2008, 06:18 PM
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Print And Cut

The main wing, tail and formers are made from 5mm EPP, the fuselage and wheel pants are from 3mm EPP. The order of construction is not critical, however there are a few points worth noting that are will make for an easier build.

Make sure that the glue is completely cured between the 6 discs that make up the spinner before sanding.
Cut out the hole for the aileron servo in part B1 before attaching part S1 which completes the upper fuselage.
Install the pushrod tubes for the elevator and rudder before attaching the lower fuselage (S8).
Install the motor before sealing the nose of the fuselage.

Okay, let’s get on with the build….

Firstly, print out the plans. I have re-formatted Kurita’s original PDFs so that they will fit onto both A4 and Letter sized paper. Printers do vary, so let me know if there are any issues. Please make sure that when you print the plans the ‘page scaling’ option in Acrobat is set to ‘None’ otherwise the plans may not print at the correct size. A number of dimensions are marked on the plans so I’d advise that you check a few measurements before you begin cutting.

There are numerous ways that you can cut the parts out, which I won’t go into here, but I’ll quickly tell you how I did it. I printed the plans onto 100gsm (heavyweight) paper and cut out all the templates using a sharp knife. I then sprayed the back of the templates with 3M75 (not 77) which is a ‘repositionable adhesive’. The templates were then laid out onto the EPP and I used a cheap hotwire cutter (see this thread : to cut the parts which was quick, accurate and worked amazingly well.
Apr 20, 2008, 06:19 PM
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Upper Fuselage Construction - Formers

5mm carbon strips are glued to the leading and trailing edges of the wing using contact adhesive (UHU Por/Creativ or Welder). I actually used 3mm x 0.5mm strips as the 5mm EPP I used was already quite rigid (the EPP available in the UK is mostly hotwire cut and has a ‘skin’ on both sides where the foam has melted during cutting). At this point I painted the wing, and h/stab yellow and marked the positions of the formers on the wing (the shaded area on page one of the 5mm plans).

Once the carbon is in place attach the centre fuselage pieces (B2 & B5). You can then glue the upper fuselage formers into position (B1, F1, F2, F3, F4, B4 & F5). Note that the top of F3 is trimmed (bevelled) to follow the contour of former B1.
Apr 20, 2008, 06:24 PM
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Upper Fuselage Construction - Sheeting

The 3mm EPP sheeting for the upper fuselage is glued into position next. Note that a number of parts (S1, S2, S3, S4 & S5) are curved to produce the rounded fuselage. I recommend that once these parts are cut you bend the foam to shape and hold them in position with tape so that when you come to glue them in place they already have a natural curve which makes gluing much easier.

S3 is glued into position first. Mark the centre line on the foam and glue this to the edge of B4 making sure it is aligned with F4 as shown in the photograph below. The edges of S3 can now be glued and held in position with tape until dry.

S2 is attached next in a similar way to create the canopy. Finally, S1 is glued in position and held in place with tape to complete the upper fuselage. Note that S1 will overhang B2 (NOT as shown in the photograph below). Once the upper sheeting is dry, remove the tape and trim any overhanging edges of S1 and S3 level with the bottom of the fuselage (B2 & B5) so that the model can lay perfectly flat on your build surface.
Apr 20, 2008, 06:25 PM
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Control Surfaces - Preparation

The next step is to attach the horizontal and vertical stabilisers. Before doing this I bevelled the trailing edge of the h/stab, the leading edge of the rudder and both ailerons at 45º. See the photographs below to make sure you bevel the correct side of the surfaces. A length of 3mm x 0.5mm carbon strip was then glued to the leading edge of the elevator for strength. At this point I sprayed the h/stab, rudder and elevator with yellow paint. Once this was done, the h/stab and v/stab were glued in position. Take your time with this part to make sure that the trailing edge of the h/stab is parallel to the trailing edge of the wing and that the v/stab is at 90º to the h/stab.
Apr 20, 2008, 06:27 PM
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Lower Fuselage Construction

Mark the positions of the two B3 formers onto B2 as shown below. The F1, B3 and F2 formers can now be glued in position. The motor mount (M1) can now be glued to the F1 formers, however it is recommended that holes to mount the motor are drilled in the ply before gluing. I installed the motor and esc at this point. F0 can now be glued in position (the centre of this former is cut out later, but I made a small hole to allow the motor’s shaft to pass through). Once dry, the edges of F0 and F1 can be trimmed diagonally (bevelled) to follow the curve of the B3 formers as shown on the plans.

The next step is to mark and cut the holes for the aileron, rudder and elevator servos. It is advisable at this point to connect the servos to the rx and esc and power them up to ensure they work correctly and the horns are centred. Toba reinforced his servo mounts with 1mm plywood strips, I omitted this step as I used more rigid EPP.

The two remaining formers (F3 & F4) can now be glued into position. Make sure that F3 has the slots cut for the aileron pushrods.

The two front fuselage sides are attached next. Originally these were a single piece of foam (as shown in the photo below) but to make construction easier they are now separate parts. As I mentioned in post #4, these parts are pre-curved using tape so that they hold their shape during assembly.
Apply glue along the straight edge of both S5 pieces and starting at the nose, attach the two parts along the length of the fuselage. Once dry, glue can be applied to the edges of the lower formers and the lower front fuselage can be completed and held in place with tape until dry.
The rear fuselage sides (S6) are glued into position next, making sure that the slots for the elevator and rudder pushrods are on the correct sides. Install the rudder and elevator pushrod tubes as shown in the photos below, and finally attach the lower fuselage (S8). The rear of the fuselage can now be trimmed to allow clearance for the elevator.
At this point I masked the wings, h/stab and hatches and sprayed the fuselage and ailerons silver.
Apr 20, 2008, 06:29 PM
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Small Parts – Spinner, Engine Cowls and Wheel Pants

The spinner is made by laminating 5 discs of 5mm EPP together as shown below. A dowel or rod is glued into the centre of the spinner to allow the foam to be attached to a drill and shaped with sandpaper. This didn’t work very well for me, as the rod I used kept coming loose as I was sanding. The best way I found of making this part was to insert a 3mm drill bit into the foam with a propsaver attached. I cut 2 notches in the spinner so that the lugs of the propsaver could be embedded into the foam. This held the foam securely while sanding. Once the foam was sanded to shape I enlarged both of the notches to fit over the propeller.

EDIT: New Spinner How-To In This Post :

The engine cowls are made by applying contact adhesive to the four edges to be bonded. Once the adhesive has dried for 5 minutes the edges are glued together and held in place with tape until completely dry (preferably overnight). To finish the cowls, the tape is removed and the part is carefully turned inside out which makes the seams less visible. Finally the top edge of the cowl is trimmed with a sharp knife to provide a larger gluing area to the fuselage.

The wheel pants are made using a similar technique to the engine cowls, but these require gluing in 5 stages due to the complex curves. It is difficult to describe in words, so hopefully the photos below provide enough detail. Note that the parts are turned inside out once stage 3 is complete.
Last edited by firetrappe; Nov 13, 2008 at 04:06 AM. Reason: Spinner How-To Link Added
Apr 20, 2008, 06:31 PM
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Engine Cowls – Fitting

This is probably the most difficult part of the build, so be patient and take your time.
I found that the easiest way to align the two cowls was to firstly dry-fit them in position using sewing pins. This way you can make small adjustments to both cowls until you are happy that they are both the same shape and opposite each other.
Once you are happy with the positions, mark the contours of the cowls on the fuselage using masking tape and then remove the cowls leaving the masking tape in position.
Begin by gluing the lower edges of both cowls in position as shown in the photograph below. Once the glue is dry the remaining edges of the cowls can be glued in position and held with pins if necessary. Once dry, remove the masking tape.
Apr 20, 2008, 06:32 PM
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Control Surfaces – Linkages and Fitting

The ailerons and elevator are hinged using Blenderm tape (also sold as Dubro Hinge Tape). Ensure that the elevator has sufficient movement, if necessary trim the rear of the fuselage to allow more clearance.
The vertical stabiliser is reinforced using a length of 3mm or 5mm carbon strip. The rudder can then be installed, again using Blenderm tape.
The rudder, elevator and aileron control horns are cut from 1mm plywood. Cuts are made in the 4 control surfaces and the horns are glued in place as shown in the photographs below. The holes in the horns should be centred on the hinge lines. Note that the aileron horns are glued on a slight angle.
Once the horns are dry, cut the pushrods to the correct length and connect them to the servos using Dubro EZ connectors.
Apr 20, 2008, 06:33 PM
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Landing Gear – Construction and Fitting

The landing gear is made using a length of music/piano wire. Toba used 1.2mm diameter for his build, but I opted to use slightly thicker 1.63mm (16swg wire) as this matched the hubs of the wheels I had.
The wire is bent to shape and glued to the second F2 former (which hasn’t been installed yet) as shown on the plans. Due to using slightly thicker wire, I made a couple of cuts in F2 so that I could embed the wire into the former.
Once dry, the assembly is glued into the fuselage which results in the wire being sandwiched between the two F2 formers. Leave to dry and then stand the model on the landing gear to check it sits level to the ground. Adjust the wire if necessary.
Finally make a small cut in both fuselage sides (S5) in line with the landing gear. The foam can now be folded over and glued to the edge of the F2 formers.
If you use thin wire for the landing gear Toba recommends that two paper discs (10mm diameter) are used to reinforce the point where the wire exits the fuselage.
Apr 20, 2008, 06:34 PM
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Wheels and Pants – Fitting

To secure the wheels to the landing gear and prevent the wheels rubbing on the pants two pieces of 1mm plywood are used on both sides of each wheel.
Firstly cut four 10mm squares of plywood and drill a hole in the centre of each piece that matches the diameter of the wire used for the landing gear. Slide one square onto each axel and bind to the wire using thread and a drop of CA as shown in the photo below.
Once dry, fit a wheel to each axel and glue the remaining ply squares in position taking care not to glue the wheel to the axel. The wheel pants can now be fitted by making a slit on the inside of each pant to allow them to fit over the wire and locate over the wheels. Check that both wheels can spin freely and then glue the plywood squares to the inside of the pants to secure.
To complete the landing gear, cut two pieces of EPP (Toba used 5mm, I used 3mm) to cover the wire between the pants and the fuselage. The EPP should be 15mm wide at the fuselage and 10mm wide at the pants. Once these are made, make an incision in the edge of each piece and glue around the landing gear wire as shown below.
Apr 20, 2008, 06:36 PM
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Tail Skid and Hatches

The tail skid is made from 1mm diameter music/piano wire which is bent to the shape shown on the plans. This is then pushed through the rear of the fuselage and secured using CA and reinforced using a length of Blenderm tape.
The servo hatch can be made in two ways. Toba’s original method shown in the photos below uses a piece of 3mm EPP for the hatch which is supported by two lengths of EPP glued to the sides of the fuselage. The rear of the hatch is glued down and the front of the hatch is held in position using Velcro. I opted to make the hatch from 5mm EPP secured at both ends with Velcro so that it could be removed completely.
The front hatch is made by laminating 3 pieces of 5mm EPP (B6). This is a tight push fit, so doesn’t require any additional Velcro.
Apr 20, 2008, 06:37 PM
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Finishing Touches

To finish the model I sprayed the spinner yellow and then hand-painted silver over the yellow to match the full size plane. The spinner is a tight push-fit over the propeller and the propsaver and so far hasn’t fallen off during flight. I drew the decals on the computer and then printed them out onto waterslide transfer paper. This technique is explained in my ‘how-to’ thread here :
The canopy was created simply using a black permanent marker (sharpie) and drawn freehand.

Once the model was finished I decided on the placement of the battery and receiver. Toba recommends that the CG is 40mm back from the leading edge of wing. To obtain this CG I mounted the rx in the front bay and attached the lipo to the F3 former using Velcro. There are a number of possible positions where the rx and lipo can be mounted to balance the model correctly, so use whatever works for you.

Well, that’s about it. Once again, my thanks to Toba, Kurita and the YSFC. Even if you don’t build this model, then at least I hope some of the construction techniques in this thread show you what can be achieved with a couple of sheets of EPP.

Happy Building!

Apr 20, 2008, 06:38 PM
Winging it Ò>
leadfeather's Avatar


Wow! Si, that is such a good looking build! Outstanding job!

Looking forward to flight reports and video. I'm hoping you are going to say that this is a good indoor plane.
Apr 20, 2008, 06:45 PM
flying with dx7...
futabafreak's Avatar
where can I buy 1 of these thats so cool!

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