First introduced in 1986, the STOL CH 701 aircraft was developed as an “off-airport” short take-off and landing kit aircraft to fulfill the demanding requirements of both sport pilots and first-time builders.
With the STOL CH 701, designer Chris Heintz combined the features and advantages of a “real” airplane with the short-field capabilities of an “ultralight” aircraft. The aircraft features fixed leading-edge slats for high lift, full-span flaperons (both ailerons and flaps), an all-flying rudder, and durable all-metal construction.
While the basic design has remained the same, many significant improvements have been introduced over the years, including a higher useful load, easier and quicker build kits, and more detailed drawings and step-by-step assembly instructions.
Short Takeoff and Landing Performance
Short-field performance is where the STOL CH 701 aircraft truly excels: It is airborne in less than 120 feet of unprepared grass, or 90 feet of hard surface, at gross weight. Rotation is possible by the time full throttle setting is applied, and lift-off can begin at 25 mph (in ground effect, with no wind) – all within less than four seconds from stand still. Of course, any headwind shortens the time and distance required for take off.
The STOL CH 701 was not designed to be just another ‘pretty’ light aircraft, but was engineered to offer outstanding short take-off and landing performance, all-metal durability, and unparalleled ease of construction. With form following function, the STOL CH701 looks like a ‘Sky Jeep’, as it is often called by its owners.
Popular since 1986, there are hundreds of STOL CH 701 aircraft flying around the world! Not many of the more than 500 STOL CH 701’s flying today can be found at airports – most are operated from short off-airport grass fields, in backyard fields and in remote areas. The aircraft’s all-metal construction makes it suitable for continuous outdoor storage – providing their owners with continuous cost savings (no hanger or tie-down fees).
The STOL CH 701 offers comfortable two-place side-by-side seating in an ergonomically designed 40-inch wide cabin. The cabin interior is designed to provide comfort for two adults. Large doors on either side allow easy access to the cabin from both sides, and can be quickly removed.
A new optional single-piece formed acrylic bubble door is available to maximize cabin width. The door is hinged at the top and each door is domed 3 1/4″ (82 mm.) to provide maximum additional cabin space. The full bubble door provides outstanding side and downward visibility. The door is fitted with the standard locking door latch (at bottom front of each door).
Better Visibility and More Cabin Width
The cabin is fitted with a large instrument panel and dual controls accessible from both the left and right seats. The center-mounted control column (stick) can easily be used from either side, and does not limit visibility of the instrument panel. Dual throttle controls are mounted on both sides of the panel for easy access. The panel measures about 34 inches across by 8.5 inches tall in the center to allow for custom avionics installations.
The dual rudder pedals also steer the nose-wheel, and are equipped with standard hydraulic toe-brakes on the pilot’s side. The baggage area is located directly behind the seats for easy access.
South African Flyer, April 2005 notes that “Due to the centrally-positioned stick, there is nothing to impede the legs when getting in. The aircraft tapers out to its widest point under the wings and visibility is enhanced by a clear plexiglass roof. There’s plenty of space and a large luggage area behind the seats is ample for carrying weekend necessities and a flight bag.”
The standard tricycle gear configuration maximizes forward visibility when taxiing, while also providing the added benefit of a level cabin while on the ground, to facilitate access to the cabin and to maximize pilot and passenger comfort.
Unlike other high-wing designs, the STOL CH 701’s wings are positioned above the cabin and fuselage to provide pilot and passengers with superior visibility. The “Above-Cab” wings taper at the wing root to maximize upward visibility while also providing superior side visibility, as the wings are located above the pilot’s head.
As all seasoned bush pilots will confirm, off-airport operations require an aircraft with superior visibility – for operations in tight areas and to allow the pilot to choose suitable landing areas. The large “wrap-around” windows and “Above-Cab” wings allow unparalleled visibility. The tricycle gear configuration also allows excellent forward visibility while on the ground – crucial when operated in off-airport fields.
Reviews of the Zenith STOL CH701
“Thanks to its thick, high-lift wing, full-span flaperons and fixed, full-span leading-edge slats, the 701 needs little more runway space than the typical backyard with clear access at the ends. Because of its stellar short-field capabilities, the 701 stands as one of the few kitplanes to serve in the sort of serious utility roles usually reserved for larger airplanes such as the Helio Courier, Piper Super Cub, Maule or Aviat Husky. That includes missionary and utility work in third world countries as well as cattle herding, fence patrol and crop dusting.” – KITPLANES magazine, January 2004
“Chris Heintz designed the CH701 some twenty years ago and it has proven itself all around the world. When the only runway is a cleared patch in the jungle, and the alternative is a week of hiking through snake-infected swamps, the 701 starts to look pretty good. This is a plane that can use almost any clearing as a runway, and its high angle of climb means that you won’t hit the trees at the end of the strip. A football field is plenty enough airstrip for a 701.” – Recreational Flyer (Canada), May/June 2005: “STOL for the people: Zenith’s amazing CH 701,” cover story by Gary Wolf and Mary Mills, pages 4 – 10.
“Well over 500 STOL CH 701s are already flying on all continents, mostly in off airport environments: Missionary work in Tanzania and Zambia, anti-poaching patrols in Ghana, doctors in northern Thailand, flying training in India. The STOL CH 701 stands as one of the few light planes to serve in the sort of serious utility roles usually reserved for larger airplanes such as the Helio Courier, Piper Super Cub, Maule or Aviat Husky. Its stellar short field capabilities and slow flying characteristics make it ideal for any bush or farm operation: herding, surveying, patrolling and protection services.” – African Pilot magazine (South Africa), June 2005 issue, pages 53 – 56, by Athol Franz
“This aircraft is great fun to fly. The Skyjeep would be an ideal item of equipment for any farmer with substantial acreage. Moreover, the design is very well suited to many aerial work requirements where short field performance and a good view are required.” – SA Flyer magazine (South Africa), April 2005 issue cover story.
“Even though it is only handsome in the way of a Hummer, the CH 701 enjoys a good reputation for its durability and outstanding STOL performance.”
“With big tires and lots of lift-enhancing devices, the Zenair CH-701 is a great backwoods aircraft on wheels, floats, or skis as Grant Rappe demonstrates.”
“Our takeoff roll was absolutely unbelievable. The only two other aircraft that I can think of that possibly could take off shorter would be a helicopter or Wayne Handley’s Turbo Raven. With a high nose pitch, the STOL CH 701 literally climbed out with two adults and full fuel at 1,000 feet per minute with about 100 feet of ground roll, breaking ground approaching 30 knots indicated airspeed!”
“The truest gauge by which to measure the quality of a kit and its kit manufacturing company are the number of its satisfied customers, the fine flying characteristics of all its finished aircraft, and the dedicated after-purchase support provided by the factory.
“By all these standards and many others too numerous to mention, Zenith Aircraft Company’s excellent reputation is well deserved. We heartily recommend to every prospective homebuilt kit buyer that he or she seriously consider the excellent aircraft produced by Zenair, a company we’ve always found to be competently and professionally managed by genuinely qualified, dedicated people.” – Norm Goyer, editor, Sport Pilot magazine (July 1993)
“With its slotted leading edges and a clear sun roof, the CH 701 makes for a good turning “ag plane. It’s not really an ag plane, per se. But it sure has a place in an ag operation. I really liked the CH701-AG… affordable to own and operate. Flying over the corn at 100 mph, making 30-second or less safe turns, an exceptional climb rate and short takeoff and landing capability, deems the 701 a viable aircraft for many spraying operations.” – Bill Lavender, Editor, AgAir Update, October 1999, pages 28 – 30.
“The Little Aeroplane That DOES”
By Mike Watson (Reprinted from Australian Ultralights, October/November 1998)
There is a new aeroplane in town that has a short, square fuselage, short, chubby wings, a sturdy set of wheels and a handsome set of bright green slats that the Fat Controller said he can keep to help him to get out of short strips.
Mandy, who took these photographs says that he reminds her of Thomas the Tank engine, who fusses around the yard, pushing, pulling, and getting everything else organized.
This is the Zenith STOL 701. Built by Max Stewart in Alice Springs with a Rotax 912 engine and a 3 blade wooden prop, its construction is of conventional metal semi monocoque, held together with aeroplane type pop rivets. The suppliers claim a build time of less than 400 hours and Max built his in around 325 hours with a fairly well equipped tool shed.
It fits comfortably into the old ultralight weight category with 2 large-ish people and some fuel. As I’m 6ft 7 inches tall I appreciate the size of the doors which go a long way forward so that getting in and out is a breeze and also by the size of the cabin which is quite high and wide enough for me to sit up straight in.
In the centre of the two seat side by side cabin there is one sidestick with a Y shaped top, so that there is no need for 2 crew to hold hands, (like in a Jabiru). There is also a massive ‘hat rack’ behind the seats, which, although it will not hold a large weight, should be OK for a couple of sleeping bags and toothbrushes.
I have been lucky enough to be asked to help in the test flying for a VH registration and I have had my opinions transformed in the process. To put it simply, aeroplanes just shouldn’t do what this one does, dammit!
The wing has full length trailing flapperons, like a Skyfox, however washout is built into the control surfaces instead of the wing itself.
The control forces are reasonably firm when cruising at normal speeds of 50Kt or more, and the forces are nicely balanced. The rate of roll can be very high, (I haven’t measured it) due to the very powerful control surfaces. The tailplane does look a little odd at first sight, as the upper surface is flat with an unusually large bulge on the under surface to make sure that there is enough aerodynamic control force to get those high angles of attack for fun take offs and landings.
At lower speeds however, the forces are light and the pitch input on the control stick takes quite a lot of movement to get the high nose attitudes required if you want a short landing. You also have to be careful not to whack the tail on the ground on takeoff if you pull back too hard on the joystick before the airspeed is high enough.
When flying slowly with reduced power, more rudder input is also required due to the reduced directional stability, however the fully flying fin has been made from a high lift aerofoil section, so that there is more than enough rudder authority to cope with directional control at all speeds.
The flaperons have 3 positions, however I find that the first 2 are more than enough for anyone. When the flaps are retracted, the STOL will cruise at a comfortable 75 knots, however, when the first stage of flap is extended, things start to become a little ridiculous.
I went out and measured a short takeoff distance, at an elevation of 2500ft, on a 22 degree day (a density height of 3700ft), with only me (at 82 kg), and 40 litres of fuel: the take off run was FOURTEEN METRES with no wind!!
Climb out with this flap setting is at 31 knots, giving close on 1000 fpm climb rate. As this is also the stall speed with flaps retracted, I tend to speed up to 41 knots before retracting flap.
If I want to really show off in a 25 Kt. wind, I can put the brakes hard on, apply power, raise the nose and take off without the wheels even rotating, however I’ve noticed that this causes other pilots to get a little upset and mutter the odd expletive, whilst helicopter drivers take to the bottle and go back to riding horses. Aah well, who wants sympathy anyway?
So how does the STOL fly? Well, apart from giving helicopters a fright, the handsome green full-length slats mean that the stalling angle of attack is somewhere around 30 degrees and flying straight and level with such a high nose attitude takes a bit of getting used to! When flying that slowly, the bite on the controls isn’t nearly as effective as when flying at more “normal” speeds. However since all the flying surfaces on the tailplane are high lift aerofoil sections, you can still make the STOL do all the silly things it is capable of.
There is a small elevator trim tab, which is operated electrically, however the control forces are sufficiently light that I only tend to use it when in the cruise: it simply isn’t necessary otherwise when you play with the dramatic changes in speed which are available!
When descending, the glide angle is quite good, similar to a Cessna 172, showing that this is a low drag airframe and although you can reduce the speed to something very slow before actually touching the ground before landing, an exceptionally steep descent is not available as the gliding characteristics are simply too good.
It is also not a good idea to do a glide approach with full flap, as the high angle of incidence means that it is difficult to get the nose up enough to land on the main wheels only. I haven’t explored this fully, but I think that the best bet for short landings is to use only the first stage of flap.
The flap control is on the floor beneath your feet which makes it a bit awkward for rapid application but it also means that it is effectively impossible to extend the flap at speeds greater than Vfe as the forces on the flap control are too great (I have no idea if this is deliberate, or not).
The landing is simplicity itself, using a robust tricycle undercarriage. The main suspension is made up of a leaf spring going right across the bottom of the fuselage with 2 upside down U shaped sections and the wheels mounted in the sections. You can buy beefed up U sections, so I guess that they have been bent in cross wind landings in the past, however I’ve had no problems and I think that with normal use, the original fit should be OK.
The nose wheel is suspended with bungees behind the engine, which are cheap and effective. If I was going into rufty tufty strips I would be concerned about things being thrown up from the nose wheel into the radiator, and I might consider some type of mudguard on the nose wheel to protect the radiator.
Is this little aircraft destined for a niche in Australia? I think definitely yes: It is a bit like the Kitfox, in that most people get out of those with a silly grin the first time as well: the reasons in this case are quite different, but, like the Kitfox, it is also simply a delight to fly. I would not be at all surprised to see these aircraft operating in the bush a lot in the future, for their ease of use and maintenance, their ease of flying, and their ability to get in and out of ridiculous places. They will make a great little workhorse.
They have the advantage in being a tricycle undercarriage that more pilots can fly them and that if they are left in a wind, they are much less likely to blow over.
If you ever get the chance to have a fly in one of these aircraft, DO take up the offer! It is simply great fun to fly.
Building the Zenith STOL CH701
The STOL CH 701 aircraft is built of semi-monocoque stressed-skin all-metal construction, just like modern factory-built planes, but adapted specifically for the kit builder. The airframe sections are designed and built so that the outer surface skin is part of the structure, with internal supports (ribs, bulkheads and longerons) to distribute the loads. The parts are fastened together permanently with rivets.
Sheet-metal construction is outstandingly the most widely used aircraft building method around the world, and has proven itself as an ideal aircraft building material since the early pioneering days of aviation. Modern alloys are lightweight, strong, corrosion-resistant and durable, while being easy to work with.
Building the STOL CH 701 one section at the time.
Unlike many other all-metal kit aircraft, the STOL CH 701 kit is made for the first-time builder, and is simple and quick to build, requiring just basic special skills, tools or jigs to assemble in a small workshop, such as a single car garage or basement workshop. Designer Chris Heintz has been perfecting all-metal construction for homebuilders since 1974, giving Zenith Aircraft Company unparalleled experience and resources in providing complete kits for first-time builders, and renowned customer support to every builder.
Sturdy and low-fatigue aluminum alloys make the STOL CH 701 airframe very rugged and corrosion resistant. The modern 6061-T6 aluminum-alloy used in the STOL CH 701 construction is durable and corrosion resistant, ideal for even the harshest environment, and very easy to repair and maintain in the field. The owner of a STOL CH 701 is assured of a long airframe life, with minimum required maintenance, as metal is not adversely affected by ultra-violet (UV) light and temperature changes like fabrics, Dacron or composites (it’s thus feasible to tie-down the aircraft outdoors to minimize costs).
Developed for the novice kit builder, the STOL CH 701 may be built from component or complete kits, or even built from just the drawing and manuals. Building a STOL CH 701 from scratch (rather than the factory kit) necessitates more time, skills, and tools, requiring about 1,500 hours to build.
“The truest gauge by which to measure the quality of a kit and its kit manufacturing company are the number of its satisfied customers, the fine flying characteristics of all its finished aircraft, and the dedicated after-purchase support provided by the factory. By all these standards and many others too numerous to mention, Zenith Aircraft Company’s excellent reputation is well deserved. We heartily recommend to every prospective homebuilt kit buyer that he or she seriously consider the excellent aircraft produced by Zenith Aircraft, a company we’ve always found to be competently and professionally managed by genuinely qualified, dedicated people.” — editor, Sport Pilot magazine
Developed for the amateur builder, the STOL CH 701 draws upon Zenith Aircraft’s vast design and manufacturing experience. The simple stressed-skin monocoque construction uses single curvature sheet-metal skins riveted to internal structural members.
The sheet-metal skins, main wing spar, structural ribs, longerons, stiffeners and bulkheads are fastened together with Zenith’s proven riveting method using blind rivets, which are as easy to set as ‘pop’ rivets, requiring only a simple hand rivet puller. The corrosion-resistant rivets provide a permanent structural bond and tight low-profile dome finish, formed by the custom riveter head. The rivet stem becomes locked in after being set to provide a water-tight seal. The 1/8-inch and 5/32-inch blind (or sohey go together predominantly with aircraft-grade pull-stem rivets, which together with the simplicity of the design make for kits that can actually be assembled in a few hundred hours.
The sturdy main wing spar is a built up I-beam, with cap extrusions buck-riveted to the spar web. In the kit, the spar comes completely pre-assembled and finished (drilled and riveted, with flanged lightening holes). The rib stations on the spar are even pre-drilled – ready for final wing assembly. The structural aluminum wing ribs and fuselage bulkheads are supplied ready-to-install (pre-formed and finished at the factory with flanged lightening holes). The surface sheet-metal skins are blind riveted to the spar, ribs and bulkheads. Many flat surface skins are pre-drilled at the factory with a drilling machine, and are pre-formed and cut, ready for assembly.
The semi-monocoque rear fuselage requires the same type of simple assembly as the wings. The square rear fuselage is easily assembled by assembling each side on a flat workbench and then simply ‘boxing’ the four sides together. The forward fuselage (cabin) is made up of factory-riveted lower side frames, and and a welded 4130 chromium-molybdenum steel top frame. Fuselage and cabin parts are supplied ready for assembly as standard components of the complete kit.
The horizontal stabilizer tail is built up of two spars and internal ribs, covered with the pre-formed aluminum-alloy skin. The elevator is fabricated like the ailerons, and attached to the stabilizer with pins at each end. The pre-formed vertical tail skins cover the internal spar and ribs.
The standard fuel system is made up of dual welded-aluminum fuel tanks (10 US gallons each).
The STOL CH 701 is one of the few kits on the market that doesn’t just come with assembly instructions. The kit includes detailed blueprints of every part of the airframe, as well as a detailed assembly manual. In fact, the STOL CH 701 can be ‘scratch-built’ from the Drawings and Manuals, although this requires additional skills, time and tools.
Drawings and Manuals
Supplied with the complete STOL CH 701 kit, the drawings are not just assembly instructions (as with most kits), but are detailed 11″ x 17″ CAD blueprints of the entire airframe assembly and individual parts, and come with an assembly manual. The STOL CH 701 Drawings & Manuals package includes a CD-ROM with high-resolution Photo Assembly Guides for the step-by-step assembly of the STOL CH 701 kit.
The Specifications of the Zenith STOL CH701
Specifications Zenith STOL CH701
Wing Span 27ft
Wing Area 122 sq.ft.
Length 20ft 11in
Horizontal Tail Span 7ft 4in
Rudder Tip Height 8ft 7in
Empty Weight 580lbs
Useful Load 520lbs
Gross Weight 1100lb
Wing Loading 9.00psf
Fuel Capacity 20 Gal.
Power Loading 13.75 lbs/bhp
Cabin Width 40in
Cabin Width (bubble doors) 44in
Load Factor (G) ultimate +6/-3 g
The Performance of the Zenith STOL CH701
Figures based on a Zenith STOL CH701 with a gross weight of 1100lbs, standard atmosphere, sea level, no wind. Range and endurance figures are quoted with no fuel reserves. All technical data, specifications and performance figures are subject to change without notice.
Performance Rotax 912 (80hp) Rotax 912S (100hp)
Top Speed (MPH) 85mph 95mph
Max Cruise (Sea Level) 80mph 85mph
75% Cruise @8000 ft (TAS) 92mph 98mph
VNE 110mph 110mph
VS1 Stall Speed 28mph 28mph
Rate of Climb 1100fpm 1200fpm
Take-off Roll 60ft 50ft
Landing Distance 80ft 80ft
Range(standard miles) 372 miles 350 miles
Endurance 4.6 hours 4.1 hours
Light Sport Aircraft Regulations
The STANDARD Zenith STOL CH701 kit aircraft meets the definition of a Light-Sport Aircraft as defined by “Certification of Aircraft and Airmen for the Operation of Light-Sport Aircraft” (7/20/04). A Sport Pilot may fly any aircraft that meets the definition of a Light-Sport Aircraft, and such aircraft does not need to change its certification category to be operated by a Sport Pilot.