About this Plan
Humbrol Mistral. Free flight glider model. Wingspan 990 mm. Uses a solid balsa Jedelsky wing.
Note the Mistral is the smaller sister to the Humbrol Sirocco (oz11386) kit.
Planfile includes detailed build instructions.
Quote: "To build your MISTRAL accurately you will require a solid, flat building board. You will also require a good quality modelling knife and blades, modelling pins, pliers and a small screwdriver. Study the instructions, plan and parts thoroughly BEFORE you begin to build the model. Identify all pieces of strip and sheet balsa, but do not remove the die-cut parts from their sheets until required. If the parts are reluctant to come out of their sheets, run a sharp knife blade around them - DO NOT FORCE THEM OUT or they could break. Use HUMBROL 66 Balsa Cement for all joints. Follow the instructions carefully in the correct sequence.
1. Join parts F1 and F2 together - Prepare a RIGHT and a LEFT fuselage side by gluing onto them strip F3 (3mm x 3mm). Ensure that part F3 on the top edge of the fuselage is fitted to run between formers F5 and F10 only.
2. Pin down the RIGHT side to the board and glue formers F4-F10 to it making sure that they are perfectly upright. When dry, glue.the LEFT side to this assembly. When thoroughly dry, unpin and glue together the rear ends of the fuselage sides.
3. Trim 1.5mm sheet F11 to size and glue in place on the bottom of the fuselage. - Repeat for pieces F12 (top of fuselage). Glue the noseblock F13 in place. Carve and sand to shape when dry - Sand the whole fuselage smooth. Cut a 2mm slot in the top of the fuselage F12 to accept the fin R1. Make sure that this slot is exactly on the axis of the fuselage. The 2mm slot in sheet F12 must be of sufficient length to allow the whole of the Fin (R1) to fit inside it.
4. Glue the tailplane supports R2 and dowel R3 to the fin R1. Fit the trim tab R4 to R4 the fin with short pieces of soft wire, R5, glued into holes in R1 and R4, having pre-drilled sections R1 R5 and R4 as indicated.
5. Glue ply plate F15 in place on the bottom of the fuselage F11, in the position shown on the full size plan. Fix the pre-shaped tow hook in place with screws and washers as shown. Note that the tow hook can be adjusted by slackening these screws.
6. Glue the fin assembly upright in the slot in F12. Sand the tailplane S smooth and round off the corners. The tail is held to the top of R1 with rubber bands looped over dowel R3. Fit the wing retaining dowels F14.
7. Trace the position of ribs W2 onto wing sheet W1. Pin W1 down to your building board, and glue ribs W2 in place.
8. Unpin the assembly, turn it over and re-pin to the board. Add the shaped leading edge W3. When dry, trim away the tapered section at the tip of W1 (as shown on full size plan). Repeat the above procedure for the opposite wing. Ensure you have a LEFT and a RIGHT wing.
9. Sand the wing roots at an angle, as shown, so that when assembled the correct angle of dihedral is given.
10. Pin down one wing and glue the other to it, propping the latter up to give a distance of 140mm between its tip and the board (as shown). ALLOW TO SET OVERNIGHT. When set, add piece W4 across the two centre wing ribs W2, as shown on full size plan. Sand the whole wing smooth.
Give the entire structure one coat of HUMBROL Sanding Sealer, and rub down with fine glasspaper when dry. Cover the fuselage with tissue, using thinned Sanding Sealer as an adhesive.
Finish the entire model with one coat of HUMBROL Banana Oil, (a non-shrinking cellulose dope). Cut a small hole in F12 at the nose as shown on the full size plan.
Assemble the model and add plasticine to the nose (through the hole) until the model hangs level when supported by a finger under each wingtip at the joint line between W1 and W3. Check for warps and remove any present by steaming.
FLYING INSTRUCTIONS: Test glide the model by giving it a firm push into the wind - do not hurl it like a javelin! Remove nose-weight to cure a dive, or add weight if the model stalls. NB Whilst plasticine is included in the kit, it may be necessary to add extra weight before flying.
Make a towline from 50 metres of 10kg monofilament nylon fishing line with a split ring or small curtain ring tied at one end. Tie a coloured tissue streamer about 50cm ahead of the ring, this aids release of the line at the top of launch and also enables you to see the end of the line when you wish to recover it.
Unwind the line and hook the ring onto the towhook. Get your helper to hold the model shoulder high. Now begin to trot steadily into the wind towing the model behind you. Your helper should release the model as he feels it begin to lift from his hand. Do not tow the model too fast or it may veer sharply to one side. If this happens LET GO OF THE LINE IMMEDIATELY! The towline may be increased to 75m as desired.
For windy conditions adjust tow hook to forward position, in calm, move towards rearmost position."
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User commentsFor anyone interested in the process of stitching and cleaning that goes into these old plans, here at Outerzone, to get them into better shape for posting online, I started a thread on RCGroups (using this scan of the Humbrol Mistral as the subject) at https://www.rcgroups.com/forums/showthread.php?3726703-Humbrol-Mistral-Plan-Cleaning-Tutorial
SteveWMD - 20/10/2020
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