Do you like models of jet aircraft? Did you know you can fly a model of a jet without the a ducted fan or a turbine propulsion system? If this sounds good to you, welcome to the world of Slope Jets. Not many things in model aviation look as good as a Navy jet flying over the ocean or a lake, unless it’s a ground-attack jet flying over terrain, or a high altitude spyplane flying high overhead. The models you see in these photos are gliders. Yes gliders. They are unpowered model sailplanes flown in the lift created by wind blowing up a hill.
The two main types of R/C glider flying are thermal and slope. Thermal sailplanes use the rising of air created by sunlight warming the ground to gain altitude, the same source of lift used by hawks and eagles as they circle upward without flapping their wings. Slope sailplanes fly in rising air created by wind blowing into the face of a hill and forced upward, producing lift in front of the hill or ridge. Slope lift is present when you see a gull or flock of pelicans cruise horizon-to-horizon without flapping. Models designed to fly in thermal or slope lift can stay aloft as long as battery packs and pilot stamina hold out.
Dave Garwood’s Sukhoi Su-25 Frogfoot, from an original design molded fiberglass fuselage designed and produced by Carl Mass. Flown here at the Southern California Spring PSS Festival.
REASONS WHY WE LIKE SLOPE JETS
Slope jets have a special appeal to many of us, and I asked slope pilots why.
Jan Carstangen: “They just plain look different than all those P-51s, P-40s, P-63s, and that makes them stand out. The scale speeds are more realistic – jets are way better in simulating them. It’s easier to imagine a jet noise than a reciprocating engine noise when the plane hauls by you on the slope. They look way better than prop planes.”
Jeff Fukushima: “Slope jets don’t have missing props or have big flat noses. Slope jets look powered! They are sleek, fast and naturally streamlined.”
Mike Gantner: “The designs are clean, low drag. Jets are crowd pleasers. For foam designers the single engine jets have a strong rear fuselage. The air show jets have great trim schemes. The bubble canopies are easy to detail and you can see the pilot figure real well.
Alex Paul, “From a good pilot’s perspective flying slope jets in formation allows the fliers on the line to work together, communicate, coordinate maneuvers, and strive to perform like the Blue Angels. It sure is fun to watch when the pilots get in the groove.”
Joe Chovan; “Jets have no props up front, so fewer liberties are taken when building them to scale for the slope.” and “The aerobatics we do on the slope are often suggestive of several routines performed by modern jet show teams– big, smooth and fast.”
Carl Maas: “No props to get in the way! They just look cool. The pilots look cool too!
There are great looking paint jobs available (civilian versions as well as military).”
Jack Cooper: “Slope Jets are cool because they look AWESOME in the sky.”
Republic F-84 Thunderjet slope glider built by Brian Laird as part of an ISR club project. Designed and built from scratch the 1/10 scale model features a fiberglass fuselage and sheeted foam core wings. Photographed by Carl Maas at the Spring PSS Festival using a Canon 40D.
WHERE WE GET SLOPE JETS
We don’t see slope jet kits on the shelf at every local hobby shop, and not every online sailplane supplier stocks them. There are three basic sources for slope jets: an original design, a modification of a powered model kit, or from small specialty sailplane makers.
1. Design your own model
You hard core builders can get any jet type you want, in the size you want, modeled in the weight you want if you do it yourself. Examples of this strategy are Lynsel Miller’s English Electric Canberra, and Walter Bub’s Grumman A-6 Intruder, and Steve Savoie’s Lockheed U-2 Spyplane. Start with three-view drawings. My favorite source for 3-view drawings and photographs is Bob’s Aircraft Documentation in Costa Mesa, California
Brian Laird’s own-design, scratch built Messerschmitt Me-262 Stormbird flown at Southern California PSS Festival is but one of several in a long line of his original design model aircraft. Another is his Aerospatiale Caravelle airliner. Probably the best known Power Scale Soaring (PSS) designer in the country today, Brian has been imagining, building, and producing highly innovative models at Slope Scale in Moreno Valley, California for nearly two decades.
Brian Koesler enthusiastically models the Sukhoi Su-27 Flanker, and he designs, builds and flys a new Flanker every year at the Southern California Power Scale Soaring (PSS) Festival.
Carl Maas in Corona, California is known for design and prototyping the most exotic of PSS models, including the Sukhoi Su-25 Frogfoot, Soviet Bloc counterpart to the NATO Fairchild A-10 Warthog, and a huge Boeing B-29 Superfortress that carries and drops a Bell X-15 rocket plane.
If you are a sailplane designer and PSS jet lover, you know who you are.
2. Convert a power plane kit
For experienced slope builders, conversion from a fuel-power kit presents possibilities. Bob Powers’ McDonnell Douglas F-4 Phantom is an example. The plane sat built but unflown as a powered model and Bob decided to pull off the fixed landing gear and add a nose cone where the engine used to go, and throw it off a hill. While it looked mighty cool, it didn’t fly terribly well, requiring massive lift, and rolling poorly as the ailerons were small. Something to keep in mind for the next conversion.
Another example is my own Douglas A-4 Skyhawk converted from a Yellow Aircraft ducted fan kit. Working to keep it light, I closed up the retractable landing gear bays and extended the ailerons to the full span of each wing half. While it looked pretty good in the air, it was too light for good performance and the ailerons were too sensitive for me during the early flights.
Dave Arnold flew a Mikoyan-Gurevich MiG-21 “Fishbed” at the 2009 PSS Festival, a slope jet converted from a balsa ARF power model kit. Good model airplane design, especially scale model design, is harder than it looks, so support our designers who have painstakingly worked out the designs, tested them, and produced kits so we can just build and fly.
3. Slope Jet kits
A great option is to purchase a kit from one of the slope specialty makers. You may have to hunt a little for a slope jet or other PSS model that pleases you, but at least the design and testing work has been completed.
Jeff Fukushima in Monterey Park, California, is one of the guys I’m happy to have designing models for us. I especially like his Grumman F9F Panther, and I look forward to new designs Jeff keeps showing us at the SoCal PSS Festival.
Dan Sampson in Los Angeles, California is a master molder, and has taken over production of the Slope Scale line of PSS models, including six slope jets kitted in fiberglass: Northrop F-20 Tigershark, Lockheed P-80 Shooting Star, Bede Aviation BD-5, Republic F-84 Thunderjet, North American Aviation F-86 Sabre, and Lockheed U-2 Dragon Lady. If you favor building molded fiberglass fuselages and sheeted foam wings, Dan will get you set up with a slope jet kit.
Magnum Models makes a foam Northrop F-5 Tiger kit, MM Glider Tech kits a Lockheed P-80 Shooting Star, and California Sailplanes lists foam Lockheed U-2 Spyplane and Northrop F-20 Tigershark kits. Jack Cooper at Leading Edge Gliders makes a EPP-foam PSS sailplanes in several sizes. His slope jets include Lockheed P-80 Shooting Star, Fairchild A-10 Warthog, Bede Aviation BD-5, Horten Go-229, Messerschmitt Me-163 Komet, North American F-86 Sabrejet, and U-2 Dragon Lady. The 60-inch P-80 was a favorite at the Midwest Slope Challenge Foam Warbird Race.
Whether you design your own, modify a powered model, or purchase a kit, when in the air your slope jet is sure to attract attention and draw questions.
Those with photo credits not mentioned were taken by Dave Garwood
North American Aviation F-86 Sabre slope glider built by Brian Laird as part of an ISR club project. Designed and built from scratch
the 1/10 scale model features a fiberglass fuselage and sheeted foam core wings. Photographed by Dave Garwood at the Spring PSS Festival.
North American Aviation F-86 Sabre slope glider built by Jeff Fukushima as part of an ISR club project. Designed and built from scratch the 1/10 scale model features a fiberglass fuselage and sheeted foam core wings. Photographed by Dave Garwood at the Spring PSS Festival.
Leading Edge Gliders EPP foam Lockheed P-80 Shooting Star built and flown by Jim Harrigan in the Foam Warbird Race at the Midwest Slope Challenge in Lucas, Kansas. Photographed by Dave Garwood at the Midwest Slope Challenge.
Joe Chovan and Jack Cooper turn and burn over Wilson Lake in Russell County, Kansas, flying Leading Edge Gliders 60-inch span Lockheed P-80 Shooting Stars, build from EPP foam. Photo by Dave Garwood
Dave Garwood’s Leading Edge Gliders 60-inch span Lockheed P-80 Shooting Stars. Build from EPP foam and covered with Solartex heat-shrink fabric, and finished with paint and stick-on markings, it shows how good a foam plane can look.
Slope scale 48-inch span Lockheed P-80 Shooting Stars, build from molded fiberglass fuselages and foam-core, balsa-sheeted wings covered with Solartex and painted. Joe Chovan built both of these planes in order to have matched flight characteristics for flying together.
Dave Garwood’s Magnum Models Northrop F-5 Tiger flying over Wilson Lake in Kansas. The model is constructed of EPP foam and packs small for transport.
Dave Garwood’s Magnum Models Northrop F-5 Tiger finished in Ultracote with Sharpie marked panel lines. Lettering is cut from sign lettering vinyl and Swiss national markings are cut from Ultracote.
Dave Garwood’s Sukhoi Su-25 Frogfoot, from an original design molded fiberglass fuselage designed and produced by Carl Mass. The balsa-sheeted foam core wing is covered with Solartex and painted. Paint scheme is airbrushed, with maekings cut from sign lettering vinyl. Frog tail marking is hand-painted.
Brian Courtise’s Aero L-39 Albatros over Cajon Summit ridge at the Southern California Spring PSS Festival. This model was converted for slope soaring from a fiberglass powered model kit.
Messerschmitt Me 262 Schwalbe (“Swallow”) an original design built and flown by Brian Laird at several PSS Festivals. It has a fiberglass fuselage and nacelles, balsa sheeted foam wing. Photographed at PSS Festival by Joe Chovan.
Sukhoi Su-27 Flanker, and original design by Brian Koesler. the Flanker is built from EPP Foam and covered with Solartex. Photographed just before a launch at the Spring PSS festival by Brian Laird.
Author Dave Garwood with Douglas A-4 Skyhawk, converted for slope flying from a Yellow Aircraft ducted fan kit. Molded fiberglass fuselage, sheeted foam wings, in the background is Lake Ontario. Photographed by Joe Chovan.