FAQ

The 12 most commonly asked questions about Trikes

1. What is the difference between a weight-shift control aircraft and a trike?
2. I just heard about weight shift aircraft. How long have they been around?
3. What are the controls, how easy are they to fly?
4. I hear the controls are opposite. What about transitioning from the classic stick and rudder airplane controls to a weight shift?
5. How do they stall?
6. How fast do they fly and what is the range?
7. How much wind can you fly in, what are the cross wind limitations, and how do they handle turbulence?
8. How do they handle bumps and turbulence?
9. How fast can they climb and how high can they go?
10. How do they glide with the engine shut off?
11. What about transporting and storage?
12. How do I decide what trike to buy?

Here we will answer these questions to provide you a new option to fly.

1. What is the difference between a weight-shift control aircraft and a trike?

Historically, ultralight, ultralight trainers and light sport aircraft flex-wings with a tricycle undercarriage have been called trikes, microlights and powered hang gliders. The FAA has officially named this two place light sport aircraft category a “Weight-Shift Control Aircraft” as a new category of aircraft like airplanes, helicopters, balloons and powered parachutes. We will use the term “Trike” and “Powered Hang Glider” to describe both single place ultralight and two place light-sport aircraft.

2. I just heard about weight-shift control aircraft. How long have they been around?

Trikes first appeared in the late 1970’s when hang gliders evolved from primitive delta wings to efficient flying wings with higher aspect ratios, defined airfoils, and wing twist providing stability and performance. The wings have evolved over 30 years along with hang glider wings to be highly refined performance machines. Trikes have been certified to strict government standards in Europe, Australia and now in the United States.

3. What are the controls, how easy are they to fly?

It is important to understand that the trike is trimmed to fly at a certain speed, we will use 60 MPH since it is where my trike is trimmed. To can let go of the bar, in calm air, and the trike will fly it self straight and seek the trim speed designed into the wing. Slight corrections in direction must be made similar to letting go of the wheel in your car or the wheel or stick in your airplane. Some trikes have adjustable trim to fly at different speeds.

The secret to learning to fly a trike is to use an easy touch on the controls similar to conventional aircraft.

Most fixed-wing airplanes have three-axis controls, early ultralights and Ercoupes aside. Those controls are: ailerons, elevator, and rudder controlling roll, pitch, and yaw.

The Weight Shift Trike has two axis controls, roll and pitch. No pilot input is required for yaw control. The design of the swept wing with a certain amount of twist and airfoil shape provides automatic yaw control which centers the ball. Thus, they are comparatively easy to fly because you are only controlling two axis rather than three axis.

How does the weight shift control work?
When you shift your weight to one side of the Trike, it warps the wing by providing more twist on one side. This variable wing twist is similar to the Wright brother’s wing warping for control, where they used cables to change the angle of attack of the wing tips. You shift your weight and it changes the twist in the wing, which produces the roll.
When the hang gliders evolved from crude delta wings to flying wings in the 80’s, the “floating crossbar” became the industry standard control system used on modern flex-wings. This simple wing warping is the key to the weight-shift control wing efficiency and rapid roll response.

Pitch is simply pushing the nose up and pulling the nose down.

Control is intuitive because you have hold of the wing and it goes where ever you move it. The motions are similar to riding a bicycle or motorcycle.

4. I hear the controls are opposite from a regular airplane. What about transitioning from the classic stick and rudder to a weight-shift control trike?

Yes, the controls are different than the fixed wing three axis. The controls are natural for someone who is first learning to fly. New skills/habits must be learned by the airplane pilot. It is very different at first for an airplane pilot because you take away the thin walls that provide a false sense of security of being inside something, you take away the horizon reference the pilot usually uses to control the aircraft, than you reverse all the controls so nothing is familiar.

Typically, airplane pilots feel disoriented for the first 20 minutes, and must “think” about the movements for the first hours of flight. There is a large variance in how quick an airplane pilot feels comfortable flying a trike. The “danger zone” for an airplane pilot is the time between when they feel comfortable flying the trike and when the correct habits are developed for flying in bumps close the the ground. Some pilots can feel comfortable flying a trike in as little at 5 hours, but it takes at least 20 to 50 hours for the proper habits to be developed. The main danger is flying close to the ground in bumps where pushing out to slow up and pulling in to speed up is critical. Some pilots pick it up quickly, others take longer. It is a matter of learning to “fly the wing” rather than move and coordinate the controls.

5. How do they stall?
The trike wing stall is easy, gentle, and very forgiving. It stalls like a canard wing. Why? The nose at the front of the wing is at a higher angle of attack than the tips. At high angles of attack the nose buffets first, looses lift and naturally falls through while the tips in back keep flying. In addition, the pendulum effect with the weight underneath naturally brings the nose down. Both factors results in a stall resistant aircraft.

6. How fast do they fly and what is the range?
Trikes have traditionally flown in the slow, stalling at 25 MPH, cruising 30 to 40 MPH, and medium speed ranges, stalling at 30 MPH and cruising 40 to 60 MPH. Now, with newer wings and larger engines, trikes are moving into the fast speed range. For example, a trike with a large 19-meter wing (200 square feet) can fly slowly. With a 16-meter wing (170 square feet) you can fly in the medium speed range. Trikes with small wings, 11 meters (115 square feet) can now achieve faster speeds cruising 80 to 90 MPH.
A trike undercarriage or chariot as they are called, can be fitted with different wings. Generally the wing of a trike represents about 25-percent of the total cost of the machine. If your budget can handle the expense, you can own a small and large wing and alternate them on the same undercarriage to increase your flying options. However, smaller wings generally need more engine power.

New trikes now have enclosed cockpits to keep the wind off of you at higher speeds.

With speed comes range. Assuming two to five hours worth of fuel, LSAs can travel from 70 to 400 miles, depending on the aircraft’s speed, engine, and fuel capacity. LSAs are powered by two- or four-stroke engines. Four-stroke engines offer better range with the same fuel capacity because they use significantly less fuel than the two-stroke engines. Trikes are very fuel efficient because no tail is required reducing drag and weight.

7. How much wind can you fly in, what are the cross wind limitations, and how do they handle turbulence?

Generally, for an intermediate or advanced pilot, you can fly in a headwind about half your stall speed and a cross wind of one third your stall speed. This is what I recommend to most pilots and have established as a basis of limitations in the “Weather to Fly for Sport Pilots” training module.
Trikes and fixed-wing aircraft can taxi, takeoff, and land in comparable crosswind conditions. The configuration and size of the wing affects crosswind capabilities for both types of aircraft. Higher-speed aircraft typically have greater crosswind capabilities because higher speeds means less crab angle on approach. To land a trike in a cross wind, you line up on the run way center line naturally crabbed into the wind and fly it crabbed to touchdown. As your back wheels touch, the nose wheel swings around straight down the runway. No slipping or cross control techniques are needed to land in a cross wind.
Cross wind takeoffs are similar. When you pop off, the wing naturally weather vanes into the wind setting up a grab angle for you to proceed directly down the center line of the runway. Experience allows greater wind limitations.

In turbulence, the wing moves more than the undercarriage resulting in less bumping around for the occupants. Since the weight is under the wing the wing and undercarriage naturally want to seek level flight. In moderate to severe turbulence you must hold onto the bar which takes some muscle and can be fatiguing on long flights.

9. How fast can they climb and how high can they go?

First off, lets discuss the performance advantages of the trike. With no tail and the associated down force and drag of the tail structure plus control surfaces, weight and associated drag is reduced. This means better climb rates and ability to carry greater loads. Let me give you an example of my medium size wing with a small but efficient 50 HP engine. At sea level, I climb at 1000 feet per minute and have climbed to 17,000 feet (Yes I used oxygen). Fully loaded with 2 people, I climb at 500 feet per minute at sea level and can reach 11,000 feet. This configuration is small engine, low drag and medium sized wing stalling at 30 MPH, hands off trim at 45 MPH, and max cruise at 65 MPH. A large engine (100 HP) on a smaller wing (13 meter) single seat will climb at 60 MPH and 2000 feet per minute. Your speed, climb rate and service ceiling depends on your specific configuration.

10. How do they glide with the engine shut off?
Trikes are efficient aircraft and glide nicely at about a 6 to 1 glide ratio with the engine shut off. It is common practice to shut the engine down and land on a spot.

11. What about transporting and storage?
One of the main advantages of a trike is the ability to fold the wing into an 8 inch diameter tube 16 to 20 feet long, and roll or drive the under carriage into a garage or trailer. It can easily be taken down or set up in less than 60 minutes. It can than be transported easily which is one of the reasons many are choosing the trike as the light sport aircraft or ultralight option.

12. How do I decide what trike to buy?
You must determine what trike life style you desire to determine what type of trike to buy. But an example would be the airport to airport model with a small wing, and a big engine model. The other extreme would be taking off on a sandy beach with a big wing and fat tundra tires where drag does not matter because you do not want to go fast or far. There are many combinations in between considering wing size, wing configuration, engine size, undercarriage configuration and accessories. Overall, you must first decide what configuration, than find the brand and dealer who can supply it. It is like buying a car. You must decide upon a SUV, sports car, truck, mini van, or RV. Than you go looking for the dealer who can supply it.