Radio Control: Giant Scale

Radio Control: Giant Scale

John A. de Vries 4610 Moffat Lane Colorado Springs, CO 80915

Overview

Sure they're big — that's the name of the game. Giant Scale fuselages and massive wings seem to go on forever. Building a Giant model poses a persistent space problem: normal-sized workbenches restrict the Giant Scale modeler and hangar rash is often the inevitable result. To solve this I built a simple giant workbench that took about half a day and gave me an efficient workspace. Here's how.

Workbench Construction

Materials

• 1 sheet 4 ft. x 8 ft. of 3/4-in. plywood (choose one good side)
• Lumberman sawing to produce two 2 ft. x 8 ft. pieces (equal width)
• About 22 ft. of door molding (about 2¼ in. wide)
• 1/2-in. Homasote (insulating wallboard), 2 ft. x 8 ft. piece
• 1-1/4-in. wood screws (plenty)
• 3/8-in. common bolts (for leg attachment)
• Set of steel workbench legs (knock-down style from a hardware store)
• Finishing nails (few)
• Tools: electric drill with appropriate bits, hammer, saw (if needed), countersink

Assembly (step-by-step)

1. Choose the bench location and build it close to where it will be used — the finished bench will be heavy and super-stable.
2. Lay one plywood piece with the good side down. Position the other piece with the good side up so the edges match and warps oppose each other.
3. Hammer four finishing nails to hold the sandwich while assembling.
4. Drill holes through the upper piece of plywood about every 6 in. around the edges and several in the middle.
5. Fasten the two plywood pieces together with 1-1/4-in. wood screws. When finished you will have a flat panel about 1-1/2 in. thick.
6. Position the assembled steel workbench legs about 8 to 12 in. from each end and mark bolt locations.
7. Drill holes clear through the plywood and bolt the legs with 3/8-in. common bolts. Countersink the bolt heads so the bench top is flat.
8. Flip the bench onto its legs and check for level.

Homasote and Molding

1. Align the 2 ft. x 8 ft. Homasote sheet on the plywood top, smooth side up, and tack it at the four corners with finishing nails.
2. Frame the entire bench with the door molding (thicker side up). The molding covers the raw plywood edges and should be flush with the Homasote surface.
3. Mount the molding with screws counter-sunk flush with the surface. Mitred corners protect the Homasote from sifting.
4. The Homasote-backed top holds pins well and can be flipped or replaced when worn.

Covering Advice

• Do your covering only on very dry days. If necessary, bring the model into an air-conditioned house for 24–48 hours before covering; covering laid over a damp frame will wrinkle when it dries.
• Recommended covering material: MonoKote.
• For compound curves (canopy, wing tips) I use Black Baron — it works beautifully.

Radio Installation

Batteries

• A standard 500‑mAh flat battery pack fits with a little clearance carved from the canopy block.
• New flat packs (1/2A 500‑mAh and 1/4A 600‑mAh) are only 1/8 in. high and fit perfectly.

Servos and Receiver Layout

• The area between F1 and F2 will take two standard servos; receiver typically goes between F2 and F3.
• Common arrangement:
• Receiver and elevator servo between F1 and F2
• Rudder servo between F2 and F3
• Spoiler servo: a standard-size servo may fit tightly; consider using a microservo mounted between F3 and F4 if necessary. If your pushrod housing diameter differs, you may be able to fit a standard servo.

Switch and Tow Hook

• Mount the main switch on shuttered F2, or install a Du-Bro switch mounted high on F2.
• A retractable tow hook can fit under a Futaba servo (and most standard servos); a Fourmost hook will fit if you want one.
• The hook can be activated by the spoiler servo or by a microservo (e.g., Futaba S‑33) mounted directly in front of the hook and next to F2.
• An E‑Z connector on the hook arm allows a pull string to clear the rudder servo and reach the microservo arm; installation is tight.
• Simple spoiler actuation: slip a looped spoiler pull string over ball links on the spoiler servo arm and secure the other end to the spoiler with a toothpick — the toothpick tightens as the string is pulled.

Flying Notes

Flight Characteristics

• The 3M Scooter is as stable as a trainer. Turns are fairly tight and stalls are very shallow — nothing tricky for a competitive sailplane.
• My first prototype (58 oz.) was too light; adding about 6 oz. gave optimum flight times.

Center of Gravity and Towing

• Recommended CG: right in the middle of the spar.
• Tow hook: place exactly at or just slightly forward of the CG.
• After flying safely and learning the model's behavior, you can move the CG aft to reduce decalage and increase gliding speed.

Ballast

• For extra ballast on windy days: slide each wing about 1 in. outward on the wing rods and insert 1/2-in. O.D., 1-in.-long slugs.
• For smaller increments: insert six 1/2 x 1-in. wood dowel pieces and then add six slugs.
• Each wing panel can accommodate up to twelve 1-in.-long units.
• Lead is best, but steel slugs are acceptable; 1/2-in. O.D. brass would be a nice option.

Design Trade-offs

• Slow-floating sailplanes look beautiful aloft but may struggle to escape bad air quickly.
• Very fast models (50–80 mph) need super lift to stay aloft; without it they land quickly.
• The 3-Meter Scooter strikes a middle ground between float and speed.

Rules and Classification

• In a previous column I suggested considering fuselage length for classifying modern ducted‑fan models, since many jets have wingspans shorter than fuselage lengths and may not meet the 30-in. IMAA Giant span definition.
• I received a letter from Ford Lloyd in Australia describing a neat Australian rule: a Giant monoplane is one whose fuselage or wingspan is 2 meters (79 in.) or larger. This handles many big ducted‑fan monoplanes neatly.

Tips and Sources

Templates (freezer paper method)

• George Chwascinski (Nashville, Illinois) recommends freezer paper as a cheap template material (~$2/roll).
• Trace the pattern on the freezer paper, stick it to balsa or plywood with a MonoKote iron, cut and sand, then strip off the paper — neat and clean for scratchbuilding Giant Scale parts.

Giant Scale Spitfire Drawings

• Ralph Ropp offers 1/4‑scale drawings and accessories for the Supermarine Spitfire (Mark IX).
• Contact: Ralph Ropp, P.O. Box 608, Rocklin, CA 95677; tel. 916/782‑6166.
• Specs: 110‑in. span; with a Sachs‑Dishler 5.8 cu. in. engine it should weigh about 35–40 lb ready to fly. Built‑up construction — a magnificent project for Giant Scale builders.

Transcribed from original scans by AI. Minor OCR errors may remain.