Radio Control: Slope Soaring
Wil Byers Rt. 4, Box 9544 West Richland, WA 99352
Introduction
Get a hold of your joystick(s) this month. Push in the down elevator for some Top Gun performance — I received two extremely interesting letters about power-slope soarers (PSS) and want to share them in this month's column. The letters include information about warbird models, an interesting scale model, and the flying the pilots do with these ships. Read on and watch out for the high-G turns.
Steve Hinderks
Overview
Steve Hinderks has built and shared two impressive RC aircraft: an A-4 Skyhawk (in Blue Angels markings) and an exceptionally realistic RC gull. The gull is especially notable for its scale appearance and the fact that, unlike the real bird, it can fly inverted.
Video
Steve sent an excellent home-produced video. It starts with spectacular flying: the A-4 is flown through four- and eight-point rolls and loops. The film also features the RC Gull flying along the slope in graceful fashion. The highlight is cockpit-mounted footage inside the Gull during slope runs, showing what landing looks like from inside a model glider. The video is lively and exceedingly well done.
RC Gull — Description and Performance
- Type: Rigid flying-wing, scale replica of a beachcomber gull
- Wingspan: 40.7"
- Length: 16.6"
- Wing area: 206 sq in
- All-up flying weight: 16.3 oz
- Wing loading: 11.4 oz/sq ft
- Controls: Elevons driven by two servos
- Stability: Eppler 168 airfoil used for flying-wing stability; clear plastic vertical fins provide directional stability
- Construction: Fiberglass fuselage; foam-and-sheeting wings; ample room for receiver and battery pack
- Finish: Detailed paint job to resemble a typical beach bird
The wing loading should give the Gull decent penetration into sea breezes while still maintaining scale-like low-speed handling.
Kit Options
Steve offers the Gull as a kit in three completion stages:
- Plans only
- Body and wing cores cut
- Glass body and wing cores finished
These options let the builder choose how much work Steve completes and accept or reject associated labor costs.
A-4 Skyhawk — Description
Steve's A-4 Skyhawk is a scratch-built PSS model replicating the Blue Angels version. Construction details provided by Steve:
- Fuselage: Bulkheads and stringers, sheeted and glassed
- Finish: Hand-cut letters from MonoKote Trim Sheet (decals not available at this size)
- Likely wing/stab construction: Foam cores with sheeting (not specified by Steve)
If you admire Steve's workmanship, consider writing to him to learn construction techniques. He was also working on another slope ship using pitch control.
Contact for Steve Hinderks:
- Address: 307 Canham Rd., Scotts Valley, CA 95066
Gregg Goris — A-10 Thunderbolt II (Warthog)
Background and Design Goals
Gregg Goris built a PSS model of the A-10 Thunderbolt II ("Warthog") with the goal of a small, light power scale slope ship. The design priorities were:
- High lift coefficient and soft stall
- Good low-speed handling and maneuverability over outright top speed
- High roll rate and agility for aerobatics
Airfoil and Aerodynamics
- Airfoil: S4233 (tripped version)
- Characteristics: Smooth polar with a high coefficient of lift and among the best tested for overall L/D; however, it is thick (~13.6%) and has higher drag at low lift coefficients
Performance and Weight
- All-up flying weight: ~163 oz
- Wing loading: ~11.4 oz/sq ft
This wing loading should allow the model to penetrate a brisk sea breeze while delivering the slow-speed handling Gregg wanted.
Construction Technique
Gregg used a combination of plastics and balsa:
- Fuselage: .040" high-impact styrene vacuum-formed over male molds, trimmed and finish-sanded
- Internal structure: A box structure installed inside the plastic shell ties the nose, radio mass, and wing mount; the box is glued into the fuselage halves
- Reinforcement: The internal cavity around the box is filled with self-foaming insulation material to lock components in place and improve crash durability
- Wings and tail: 1-lb density foam cores covered with balsa skins; tail surfaces are simple flat C-grain balsa with rounded leading edges and tapered trailing edges for an airfoil effect
Controls and Finish
- Controls: Two-channel — elevator and ailerons (to turn, roll the model and pull elevator)
- Finish: Military camouflage
Gregg notes that the thick wing, short tail, and long nose formula (developed by U-control builders) provides excellent pitch control; his RC slope model benefits from that heritage while flying in three dimensions.
Contact for Gregg Goris:
- Address: 3654 Keel Avenue, Oxnard, CA 93035
- Tel.: 805/985-8576
Scale Documentation Source (SMR)
If you plan to build a scale model (vintage, PSS, or modern), consider SMR (Scale Model Research). SMR maintains one of the world's largest collections of full-color aircraft documentation:
- Over 90,000 photos in inventory
- About 3,300 Foto-Paaks and "Koku-Fan" three-views
- Owner: Bob Banka (collection is regularly updated)
Contact SMR:
- Address: 23343 Ticonderoga, Costa Mesa, CA 92626
- Tel.: 714/979-8058
Airfoil of the Month — Quabeck 1.0/8
Profile drag can limit penetration, top speed, and overall L/D. Designers seeking slope-soarer penetration typically avoid very thick or highly cambered airfoils, which sacrifices low-speed performance and maneuverability.
The Quabeck 1.0/8 is designed for slope flying where penetration and speed are emphasized:
- Camber: 6%
- Thickness: 8%
- Characteristics: Low profile and induced drag; a "high-speed cruiser" airfoil that cuts through wind well and offers good inverted flight performance due to a low mean camber line
- Downsides: Produces relatively low coefficient of lift and is not suitable for light-lift conditions
If you have abundant lift at your site, consider the 1.0/8 for a fast, penetrating slope design.
Closing
I love hearing from modelers who start with an idea and turn it into a flying ship. Whether you scratch-build, kit, or use ARFs, sharing information keeps the hobby vibrant. If you want more details about the projects above, write the builders (include a SASE) or call the numbers provided. Push down the elevator and enjoy some Top Gun slope flying.
Transcribed from original scans by AI. Minor OCR errors may remain.
