While it is impossible to list every flight characteristic of these aircraft, here is a general description for the Sport wing machines.
The F1s and F4s are known for their sporty feel and light, smooth controls. Their ground handling is predictable and easy. While the F1s and F4s are generally docile, they can definitely bite you. They have a large ratio of stall speed to top speed, as do several of the RV models. This means that you must be very careful when using the control stick, aka the “wing removal lever” when traveling at higher speeds. Take note: depending on your machine’s construction and weight, the maneuvering speed, Va, will be about 125 knots.
Note: There are many good sources of information on the importance of understanding and abiding by maneuvering speed recommendations. Here’s one example: Accident probe: full deflection
Speeds will vary somewhat with weight, and the accuracy of your pitot/static system. Of course, true -vs- indicated speeds vary with altitude too. The speeds shown below should be in the ballpark for most machines.
Vso – Stall speed, flaps fully extended, power at idle 46 Knots
Vs – Stall speed, clean, flaps up, power at idle 52 Knots
Vfe – Maximum flap extended speed: 95 Knots
Va – Maneuvering speed: 125 Knots
Vno – Normal Operating speed (Max. Structural Cruising): 160 Knots
Vne – Never Exceed speed: 240 Knots
Vs and Vso:
Stalls are typically rather benign. The relatively fat airfoil recovers from a normal stall by just releasing some back pressure on the stick. Spins are possible, but Mark reports that F1 Rockets, being somewhat nose heavy, recover quickly. The CG will affect stall/spin characteristics. Be very careful if flying with an aft CG. Control pressures will be very light at aft CG conditions, and spins may be more exciting than planned. Each plane will vary here and only a complete flight test program will verify your aircraft’s true numbers and flight characteristics.
This is the maximum flap extended speed. You’re not allowed to have the flaps down above this speed.
Practically speaking, if your machine has a manual flap handle, you’d have trouble putting the flaps down at a higher speed unless you have some seriously huge biceps. I know this because my Rocket had manual flaps.
For most machines, putting the electric flaps down at a higher speed may be possible, but you risk bending parts, so don’t do that either.
Always retract the flaps before you exceed Vfe.
Maneuvering speed is defined by Wikipedia as the speed above which it is unwise to make full application of any single flight control (or “pull to the stops”) as it may generate a force greater than the aircraft’s structural limitations. This means a single input to a single control. This is IMPORTANT as we don’t want to bend any precious aluminum.
Above Va, or about 125 knots, you want to be very careful how you move the stick. Rolling pulls are generally a poor idea, i.e. don’t pull and roll at the same time. The asymmetric loads can do bad things under the wrong conditions. The higher the airspeed, the greater the risk.
And don’t neglect to compensate for weight. It’s somewhat counter intuitive, but lower weights mean higher Va and vice-versa. Look it up and read about it until you are certain that you understand.
This is the maximum structural cruising speed, or the top of the green arc on most ASI’s. Above this speed, is the yellow arc… or the smooth air penetration area. As with any other aircraft, use caution in the yellow arc so a gust or other upset (including control stick movements) doesn’t cause any damage.
This is the never exceed speed. This means what it says. Exceeding Vne in a properly constructed and maintained aircraft puts the aircraft at risk for structural failure. If you have a less than perfect machine, the risk increases.
To get a useful Vne number, indicated airspeed needs to be converted to true airspeed. Indicated airspeed, which decreases with increasing altitude, can be a dangerous number to use. For example, 200 KIAS at 10,000′ is 243 KTAS, which is above Vne. Make sure you understand the difference between IAS and TAS.
Based on 20 years (as of 2020) of fleet experience with the F1 Rockets, there have been a handful of incidents related to speeds near Vne. Thankfully none resulted in crashes. Although the F1s and F4s cannot reach Vne in level flight, they can certainly get close, the prudent pilot manages his (her) flight profile to stay a respectable distance from Vne. While it may be acceptable to “proof” the machine to Vne during flight testing, while wearing a parachute, only a fool exposes the aircraft and its occupants to such high speeds during routine flight.
See the links near the bottom of this page for enlightening discussion of the aerodynamic forces affecting all aircraft.
Effect of CG:
The CG has a big effect on how a tandem seat aircraft behaves. Flying an F1 or F4 solo is greatly different than how it flies after loading a passenger in the back. It is very important to have an accurate weight and balance table for your aircraft and to use it.
While it is normally difficult to aft load an F1 Rocket to aft limits, it may be much easier to aft load an F4 Raider. The big engine on the F1 Rocket offsets normal aft loads, though it is easier to overload an F1. The smaller 4 cylinder on an F4 Raider may mean less aft loading capacity. As the pilot it is up to YOU to understand this. Flying at, or near, aft CG limits makes the aircraft less stable in pitch as the CG moves aft. This can be a recipe for PIOs, and other unpleasant handling, up to and including loss of control.
The aircraft really shines under this condition. It typically flies well, lands easily, and is quite well behaved. The most notable complaint, although minor, is that an F1 will be a bit nose heavy and may have marginally adequate nose up trim available during approach to landing. On roll out, over zealous use of the brakes could bring the tail up, but normally this doesn’t cause a problem… just let up on the brakes a bit!
Flying with a passenger or aft CG:
Flying with a load in the back changes things. You’ll need to push the stick forward more aggressively on take off to lift the tail, and you’ll find that the pitch forces in flight are lower than when flown solo.
Cruise flight is generally not a problem as long as the CG is in the envelope. It may be a good idea to never let a rear seat passenger handle the control stick unless they are a trusted, competent, RV type, experienced pilot that understands that a tiny input on the control stick is all that an F1 or F4 ever needs.
Landing can be another issue altogether. New pilots should fly with a light load in the back, preferably baggage, until they get a feel for the aircraft in the landing arena. It is quite easy to over-control in the flare and induce a PIO (pilot induced oscillation). Go around if needed. When the wheels touch down, any aft load will cause the tail to continue downward, which can bounce the aircraft back into the air. If that bounce is small, and I do mean small, then the next touchdown may be suitable to continue the landing. HOWEVER, if the aircraft bounces twice: GO AROUND. Trust me, the third bounce will be worse and the 4th bounce is gonna be very bad. The titanium gear is tough, but it is a giant spring and it likes to bounce. In summary, the aft CG makes the control stick light and twitchy, and the titanium gear ain’t gonna help if you have an appreciable bounce. Just go around.
You’ll notice that I didn’t address full stall or wheel landings above. The airplane doesn’t care… as long as you don’t get a bounce started. However, most F1 pilots I know, prefer a tail low wheel landing approach to a soft touchdown.
Aerobatics are certainly a lot of fun in a sporty aircraft with light controls. The temptation to make the aircraft roll or loop can be irresistible. However, an F1 or F4 is not a Pitts, Decathlon, or an Extra. The F1 or F4, when pointed down, picks up speed at an astounding rate. It is all too easy to dangerously over-speed the aircraft. We have all too many testimonials from pilots who went dangerously past Vne while doing a roll, loop, or even while taking photos.
We absolutely recommend against inexperienced pilots attempting aerobatics. Even someone with proper training must be mindful of how fast these machines will pick up speed. Also, doing any aerobatics with a passenger is a poor idea. While the F1s and F4s are capable of aerobatics, they are NOT designed as aerobatic aircraft. You can break them in the air though inappropriate flying. Note: The aft CG you get with a passenger greatly increases the chances of over-stressing the aircraft through over-controlling. Don’t risk it.
These are amazingly capable, fun, fast, and efficient machines. They excel at traveling and are quite capable of modest aerobatics in the hands of a trained pilot. Treat them right and enjoy the ride!
Aerodynamic forces that affect all aircraft: Below are a few links, there are many others, that discuss some of the forces affecting aircraft in flight. As you can see, excessive speed can damage or destroy any aircraft.
Aeroelastic flutter and related forces
Aeroelastic phenonena 1
Aeroelastic phenonena 2