Mandrake Mk4 (oz9810)


Mandrake Mk4 (oz9810) by Jeremy Collins - plan thumbnail

About this Plan

Mandrake 4. Radio control sport model, for electric power with brushless 350-400 watt motor and 3 functions.

This is an updated version of the Mandrake (oz9577) design which was first published in Radio Modeller July 1979 (although the design dates back earlier).

Quote: "Just browsing, I notice that the Radio Modeller plan for Mandrake (oz9577) designed by me in 1969-ish was added to Outerzone in December 2017. A couple of years ago I made some updates to the original plan to take account of more modern servos, brushless motors, LiPos etc and re-drew the plan in CAD. The plan now includes all ribs drawn individually, building notes etc. Any interest in having a copy of this updated plan? Kind regards, Jeremy"

Direct submission to Outerzone.

Quote: "Construction Notes: Fuselage is constructed on a 12mm steel tube/rod mandrel. Tack glue formers F2, F3, F5-F7 and F9-F11 in position on the mandrel, check for square and add 12mm x 3mm side stringers, followed by 5mm x 5mm top and bottom stringers, checking for straight and true throughout. Add F4 and F8 and wing support rails, followed by F5A and F7A. Sheet fuselage between F3 and F9 with 2.5mm balsa, damping outside face if necessary. Make up motor mounting cruciform and glue to from face of F2, add F1. Plank fuselage between F1 and F3.

Build fin, incorporating all-moving tailplane horn and tailplane root ribs. Trim leading edge of fin to fit flush against F9 and glue firmly in place. Install elevator servo and pushrod, then plank rear fuselage between F9 and F11. Knock out mandrel from fuselage formers and remove centre of F6 and F11, add F12.

Wing construction: pin washout wedge (tapered 6mm to 0mm over a length of 60cm under trailing edge. Pin down wing bottom sheeting and capstrips, then glue in place bottom spar, ribs, false leading edge, dihedral brace and upper spar, then add spar webs. Add top surface sheeting. Glue on leading edge and wingtips and sand all to section, noting the shape of the Hoehner-type wingtips. Separate the ailerons, add leading edge sheeting to ailerons and rear of wing after chamfering ribs and sheeting. Install aileron servos. Carve wing fairing from soft balsa and fix in place, then add dorsal fairing.

Tailplane is built in similar manner to wing.

Secure motor to aluminium disc (note cooling cutouts) which in turn is screwed to F1. ESC is Velcro mounted on side stringer in battery area, battery (adjust final location to suit C of G) is secured with Velcro straps to1.5mm ply floor fixed to F5 and F6."


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Mandrake Mk4 (oz9810) by Jeremy Collins - model pic

  • (oz9810)
    Mandrake Mk4
    by Jeremy Collins
    71in span
    Electric R/C
    all formers complete :)
  • Submitted: 17/02/2018
    Filesize: 318KB
    Format: • PDFvector
    Credit*: JeremyCollins

Mandrake Mk4 (oz9810) by Jeremy Collins - pic 003.jpg

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User comments

Hi There, Is there any detail about the wing ribs? I suppose that we should take the outline from inside the rib drawings in the PDF. Is the wing completely sheeted? TIA
Ed - 14/11/2019
Construction notes are on the plan, Ed. It also says: LE sheeted top and bottom in 1.5mm balsa. The rest (behind the spar) is mostly cap strips. So no, not fully sheeted. It's all in the plan, for the reading.
SteveWMD - 14/11/2019
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* Credit field

The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.


This model plan (like all plans on Outerzone) is supposedly scaled correctly and supposedly will print out nicely at the right size. But that doesn't always happen. If you are about to start building a model plane using this free plan, you are strongly advised to check the scaling very, very carefully before cutting any balsa wood.


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