In a flying world that seems to think a 2-seater is mandatory, Mark Beierle has released another single-place ultralight. And what a sweet ultralight it is.
I love the Thunder Gull series of ultralights. When people ask me what I personally like of the hundreds of ultralights evaluated, the Thunder Gull always springs to mind (among a few other designs). My interests may not be your interests, but I’ll bet most pilots would love to fly the Gull 2000.
Offered for sale here in the new millennium, the Gull 2000 is an appropriate name that seemed well aimed at lots of American ultralight enthusiasts.
Welcome to Gull 2000
For the new century, the Gull 2000 adds to, rather than replaces the older models from Earthstar Aircraft. The company will still sell their Thunder Gull J single-seater and their little-publicized Soaring Gull, which uses a very small engine and long wings to create something of a motorglider.
For those desiring two seats, the choices are not mirror images with different engines. The older Thunder Gull JT2 is a tandem seated enlarged version of the J model. Contrasting significantly is the Odyssey, released in 1995. This ultralight features side-by-side seating in a staggered fashion that keeps the 2-seater from becoming too wide, and gives each occupant a little more shoulder room; the right seat is several inches behind the left.
The Gull 2000 shows its heritage to the older designs by offering a roomier cabin (somewhat like the Odyssey), yet with the lean lines of the single-seaters. It also employs the agile handling of the single-seaters.
One irony of these Earthstar models is that the newest is also the least expensive (though only by a small margin). The Gull 2000 sells for $10,965 without an engine and Earthstar offers a range of engines, including the 40-hp Rotax 447, 46- or 50-hp Rotax 503, 60-hp HKS 700E 4-stroke, and the Zanzottera single- or twin-cylinder models.
Certainly I find the Gull 2000 Beierle’s best work yet.
Sleek Yet Spacious
In the past, some larger pilots have complained that the Thunder Gull line is too tight inside. Indeed, in a country of beefy pilots an ultralight designed by a slim and trim Mark Beierle may not have fit the mainstream as well. That changed with the Gull 2000.
As proof, CGS Aviation’s Chuck Slusarczyk accepted Beirele’s invitation to hop inside and – surprise! – he fit with room to spare. Chuck is one of those large pilots, yet he did not look shoehorned into the Gull 2000. We had trouble getting him out, but that was because he appeared to enjoy the experience.
The Gull 2000 uses an all-fiberglass body to fair the cockpit; older Earthstar designs used some dope-and-fabric covering. Combined with numerous options, the test Gull 2000 is a little too heavy to qualify for Part 103’s weight limits, tipping the scales at 274 pounds.
Beierle says that by using a Zanzottera engine, he can keep the Gull 2000 under 254 pounds (before parachute, which, by definition, doesn’t add to the total). He referred to the 26-hp single-cylinder Zanzottera, which he’d install in conjunction with a different prop to stay within the 63 mph speed limit of Part 103. Mark admits that the Zanzottera engine will produce a greater amount of vibration owing to its single-cylinder construction, but he believes he can dampen this with softer motor mounts.
In an earlier trial with the littlest Zanzottera and by building lightly, Beierle created a Part 103 ultralight, which he says weighs only 241 pounds.
Our test Gull 2000 was equipped with the popular Rotax 503, which gave the plane superb performance. Anyone with an FAA ticket may prefer this combination or even the 4-stroke HKS. You can also downsize to the Rotax 447 engine, but as this cuts weight by only 5 pounds, I’ll wager few will give up the oomph and reliability of the 503 engine.
The inner structure of the Gull 2000 is the same welded steel construction that has always braced the Earthstar ultralights. Most surfaces are metal, but you can choose between all-metal wings or dope-and-fabric coverings. Both will last a long time; I know of no other ultralights that give you such a choice.
Flaps don’t come standard on Earthstar single-seaters and, indeed, you could easily do without them, I believe. But given the extension of the speed range, many pilots will want them for $700 more. They, too, are all metal.
While a few onlookers marveled at the small distance between the main gear, knowledgeable designers noted that the classic ratio of 4:1 is maintained (this ratio relates the width of the landing gear relative to the aircraft span). One of the endearing parts of the Gull 2000 – like the other Earthstar models – is the small wing. At only 20 feet of span and 95 square feet, I have judged this to be one of the hardest-working wings in the ultralight industry. It’s hard-working because it doesn’t seem small in flight.
But you can also select a 24-foot or 28-foot span, for example, if your typical occupant load is high or perhaps if you fly in high density altitude locations like Colorado. As with the wing covering, I’m not aware of other brands that give you such broad choices on a single model.
Beierle noted that the Gull 2000 sits very low and this reduces its need for a wider span of the gear. One of my memories is of a single-place Thunder Gull being turned very sharply at speed without noting any tendency to tip. The short span clearly helps keep the Gulls on the gear, thus the narrow gear stance is perfectly reasonable.
Beierle’s design philosophy is to make the most efficient aircraft he can, one which will use the least amount of fuel. He calls himself a minimalist and this sentiment is carried through the aircraft. While efficiency may be the hallmark of this design, it is my observation that creature comforts have been substantially improved with the Gull 2000. The environment inside the aircraft was more comfortable and wider, good news for large American pilots.
One ultralight designer examining the Gull 2000 observed that it does not use the extended dorsal fin that one sees on Titan aircraft. Indeed, though these machines share the design heritage of the early Thunder Gulls, they aren’t identical.
Levers and Knobs
The Gull 2000’s trim control has changed from the older models. Beierle moved the control knob from under the seat (on older models) to alongside the seat where you can actually look at what you’re doing. Both old and new knobs face backwards. If you think of the inward facing half of the knob and turn it downward, the nose lowers; turn it upward and the nose rises. Though this sounds awkward, it is more intuitive than the older version. Not much twisting of the knob was needed to notice the change in trim.
The flap handle is located to the left of your head and offers two notches other than neutral. This is very easy to use and to reach. Mark recommends one notch for takeoff and in most cases two notches will significantly slow the aircraft on approach to landing. In two low passes I made over a field, one with no flaps and one with full flaps, there was a speed difference of about 20 mph at a throttle setting to sustain altitude.
Creature comfort improvements include the lone entry door, which now reaches higher and extends lower to make entry and exit easier. The lower door facilitates entry by allowing you to turn around, sit down, and draw your legs in afterward, the preferred method.
On this first production Gull 2000, the door did not fit as precisely as it will. So Mark had installed some turbulator air strips to smooth airflow around the aft end of the fuselage. He seems a perfectionist in aerodynamic efficiency; many designers would have been satisfied.
The Gull 2000’s cabin is approximately 2 inches wider at your hips; the old model was 27 inches wide. What a difference 2 inches can make.
Visibility was very good in the Gull 2000, however, it was slightly better to the right because the doorframe obscures some visibility to left. And though the flap handle is a slender steel rod, it also modestly blocks vision if you have flaps deployed.
As I did my Dutch roll exercises I noticed a little fuel smell in the cockpit since the tank is in the cabin with you. Fortunately, Mark had installed window scoops on either side, which provided plenty of fresh air.
The Gull 2000 was a little bit on the noisy side, no doubt a function of the cockpit acting like the inside of a speaker cabinet. You’ll want to use a helmet or headsets.
The heel brakes tended to squeak a little bit but did prove necessary as I taxied somewhat down slope with an engine that was idling fast. Mark indicated that the reason for the increased idle speed relates to his use of a product called Energy Release, which uses a chemical process to fill small voids in the cylinder wall. This is claimed to result in a more efficient operation of the engine. The use of this special product, Mark says, caused the idle speed to increase. He’d turn it down but it would creep back up.
Ahh, the Flying
The Gull 2000 takeoff climbout was done at 55 mph and even 60 mph was useful in the gusty conditions.
I approached for landing at 50 mph, but this proved to be a little slow. I ended up touching the small tailwheel in the effort to make a proper flare, though both the Gull 2000’s Canadian owner and designer Mark Beierle told me my landing was a good one.
As I practiced Dutch roll coordination exercises, I had to add more left rudder during the left turning initiation than I did to the right. This shows coordination of the controls is not perfect on this first production Gull 2000, and Mark felt that this may have something to do with the less-than-perfect door fit. This proved to be quite a very minor defect and my later Dutch rolls were excellent to a steep angle. The whole problem no doubt will disappear when the door is done to final production quality.
In general practice I found the rudder to be a very powerful surface. In some dire circumstances where aileron control may be lost, the rudder would suffice to help you line up on a runway.
Beierle suggested I climb at 50 mph, however, when I did this away from airport traffic it produced such a steep angle of climb that the lower surface of the wing appeared to have a 45° angle. Climb is exhilarating at nearly 1,500 fpm. Of course, in a Part 103 version of Gull 2000, the climb will clearly not be as strong.
Beierle discussed the efficiency gains he’s found with the Gull 2000 and, by relating this to gallons used per hour at various speeds, he thinks he is seeing a 25- to 30% efficiency increase in the new model. I feel this is a significant accomplishment because the Gull 2000 has a wider body yet smoother airflow around it. The perfectionist succeeds!
I commonly flew at 5,000 rpm, confirming Beierle’s feeling about efficiency. However, in sharp contrast to my experience in recent months with the HKS engine, the Rotax lost considerable rpm when the nose was high and gained it when I lowered the nose, an obvious difference between 2-stroke and 4-stroke operations. Fortunately, Beierle is an HKS booster and lists it as an option in his regular literature.
However, since Mark designed for and achieved good aerodynamic efficiency, it struck me as odd that the Gull 2000 did not employ wheel pants. This decision may have been a choice of the Canadian buyer.
My power-off stalls showed 28 or 29 mph on the airspeed indicator. This is not quite what company literature lists (26 mph) but it’s very close if the installed ASI can be trusted.
Normal power-on stalls never did break over and more aggressive power-off stalls never dropped toward either wing, a benign occurrence on any aircraft but one which speaks well of Beierle’s copious design talents.
When I checked for adverse yaw, I did find a liberal amount but the hesitation in the wrong direction did not last too long and didn’t go very far. Adverse yaw is common on most ultralights but the quick correction suggests the design is well-harmonized.
After trimming for level flight, when I reduced power the nose would rise ever so slowly and when I increased power the nose would slowly begin to drop. The motion was so modest that it isn’t worth any worry.
Again trimming for level flight, I deflected the stick forward and aft in a longitudinal stability check and found that the effects were positive but that the response was very slow in the desired direction. Some ultralights are faster to correct the stick movement (ideally back to level flight), but those may not enjoy the overall performance package offered in the Gull 2000.
Fly Like a Gull
Earthstar is not a large producer, and this probably affects pricing. The Gull 2000 isn’t the least expensive ultralight you can buy but fortunately it more than compensates by its fine combination of great performance and superb handling.
Base price of the Gull 2000 kit is $10,965 (as of summer 2000). To arrive at our test aircraft, you add $4,700 for the Rotax 503 engine and an engine installation kit. Subtotal so far is $15,665.
For his Canadian customer, Beierle added other desirable features like powder coated steel structure ($295), custom-fitted carpeting ($425), wide aluminum Hegar main wheels ($240), a BRS ballistic parachute (not quoted, but around $2,200), full fuselage painting plus accent striping ($950), and instrument package including the EIS unit (total $1,215), the right-side side glass and left-side door (standard on the Odyssey but a $415 option on the single-place models), a 3-blade prop ($470) and flaps (again standard on the 2-seat models but a $700 option on Earthstar’s single-seaters)
All the above goodies sum to $6,910, making a new subtotal of $22,575. Earthstar can build the plane for its Canadian customer which would add $7,940, or you can order it with completed wings, ailerons, flaps, and wing tips for $3,450. (A fully built Gull 2000 is available to U.S. customers if the ultralight fits Part 103.)
Is it worth it all? In my opinion, yes. This is one of the best single-seat ultralight aircraft in the world and a fine aircraft compared to any other you can buy whether general aviation or homebuilt. I’d stretch to gather these funds for two reasons: First, the Gull 2000 is simply a wonderful flying machine. Secondly, it will last a very long time and I feel sure its resale value will hold up well, possibly much better than more common variety ultralights.
However, if you feel this is too much for your wallet, then I encourage you to think about the Gull 2000 set up to stay within Part 103. With a smaller (probably Zanzottera) engine, fewer options – for example, flaps you won’t really need on a lighter, slower machine – and basic instrumentation, you should be able to hold the cost to about $15,000 or so. At this price, I consider the Gull 2000 a bargain worthy of consideration by anyone who loves ultralight flying.
Earthstar is not a large company with dozens of employees, therefore its cost of production is not held down by economies of scale. However, all the better stuff in this world costs a little more and the Gull 2000 is no different. Like a Ferrari automobile, you may wait a little longer to get one and you may pay a little more, but you’ll be the envy of anyone who knows just how delightful it is to fly a machine like the Gull 2000.
For wired pilots who like surfing the Internet, the company does not maintain their own Website (as of late November 2000). However, you can point your browser to Thundergull.com and you’ll see basic information on all models except the Gull 2000. While the Website won’t help you compare details of the new machine, it does include a nice bit of history on Mark Beierle. Since this machine is wholly based on his aerodynamic savvy, the background should be of interest to anyone inclined toward Earthstar Aircraft’s offerings.
|Empty weight||274 lbs (as flown)1|
|Gross weight||550 lbs|
|Wingspan||20 ft. 2|
|Wing area||95 sq. ft.|
|Wing loading||5.8 lbs/sq. ft2|
|Fuel Capacity||5 gal. (standard)|
|Kit type||Assembly kit|
|Build time||150 hours|
|Notes:||1Fitted with the Zanzoterra engine, Beierle feels the Gull 2000 can make Part 103 ultralight weight..
2Effective span, due to the wing tips, is 22 feet, says Earthstar; a span of 24 or 28 feet is available with 133 square feet of area.
|Standard engine||Rotax 503 (as flown)1|
|Power||52hp at 6,500 rpm|
|Power loading||10.6 lbs/hp|
|Cruise speed||60-105 mph3|
|Stall Speed||26 mph|
|Never exceed speed||120 mph|
|Rate of climb at gross||1,500 fpm|
|Takeoff distance at gross||125 ft.|
|Landing distance at gross||75 ft.|
|Notes:||3Cruise can be held to Part 103’s 55 knots with a smaller engine and the right prop, says Earthstar.|
|Standard Features||Cantilevered wing, Rotax 503, independent main wheel brakes, in-flight trim, counter-balanced ailerons and stabilator, 5-gallon fuel tank, Lexan® windscreen, 4130 chromoly cage, shoulder belt seat restraint, fiberglass seat, fiberglass body, metal wings with drooped tips.|
|Options||Other engine choices, including the Zanzottera, 60-hp HKS and Rotax 447, longer wings (see specifications), instruments, door and side panels, electric starter, 2- or 3-blade composite prop, aluminum or fabric wing covering, and ballistic parachute.|
|Construction||4130 steel airframe, fiberglass fairing, aluminum or fabric wings, metal tail coverings.|
Cosmetic appearance, structural integrity, achievement of design goals, effectiveness of aerodynamics, ergonomics.
Pros – Few ultralights inspire me more than the Thunder Gull line and the Gull 2000 is the “best of breed” in my opinion. Single-seater but with more room for big pilots and more refinements than ever. Long-lasting materials used in construction. Proven design over many years; even copied. Wider speed range than most aircraft (not just ultralights). Sits on all three gear.
Cons – It may be one of ultralight aviation’s best planes, and you’ll pay for it. Gull 2000 kit sells for $10,965 and the Rotax 503 engine as tested will add more than $4,000. Cannot qualify for Part 103 with 503 engine and one that will make weight may not satisfy all buyers. Most are fully enclosed, a negative for those who love out-in-the-breeze flying (though you can order it without sides).
Subsystems available to pilot such as: Flaps; Fuel sources; Electric start; In-air restart; Brakes; Engine controls; Navigations; Radio; (items covered may be optional).
Pros – Well-equipped ultralight with in-flight trim, flaps, and differential brakes all standard; all these systems worked excellently. Electric start is available since the 503 Gull 2000 won’t make Part 103 weight. (The test plane was headed to Canada where the weight values are different.) Easy engine access. Flap handle is close yet nonintrusive.
Cons – Trim knob is better than older models, but is still counterintuitive to use. No trim position indicator. Fueling is done inside the Gull 2000 – unless you remove the tank, itself a hassle – and some fumes were noticeable. Panel space is minimal if you must add more instruments or radios. Heel brakes aren’t every pilot’s favorite.
Instrumentation; Ergonomics of controls; Creature comforts; (items covered may be optional).
Pros – Easier entry than older single-seat Gull models, thanks to a door that extends both lower and higher. Beautifully appointed interior; a carpet kit is available. Excellent use of interior space makes it seem larger; big pilots will fit quite easily. Superb visibility out either side and forward. Good seat belt restraint. Comfortable seating for longer flights.
Cons – Rearward visibility no better than many other enclosed ultralights. Baggage area is quite limited (though Beierle flies across America in the Gull 2000, he’s a minimalist). Left side door only. No quick seat adjustment.
Taxi visibility; Steering; Turn radius; Shock absorption; Stance/Stability; Braking.
Pros – Low stance, good weight distribution, and trailing link nosewheel make for easy ground handling. Nosewheel has some suspension, thanks to fiberglass rods. Wide aluminum Hegar tires ($240 option) gave excellent grip. Excellent nosewheel response; extra weight up front surely helps. Turns very tightly. Taxi visibility is very good.
Cons – Clearance could be an issue if you land out in an especially rough field. Main gear is not suspended except via air in the tire and gear leg flex. Heel brakes can be “dragged” without realizing your error. It gets warm inside this (optional) full enclosure, at least until air inlets start working.
Qualities; Efficiency; Ease; Comparative values.
Pros – Jumps off the ground with the best of them; factory says only 125 feet is needed (with Rotax 503). Gull 2000 slows beautifully for landings in smaller areas; factory reports 75 feet with brake use. Crosswinds are only a problem if your skills are new or rusty. Slips work well, as do the large flaps. Good energy retention means smoother touchdowns.
Cons – Smoother runways are much preferred as ground clearance is less than some ultralights. Except for a warm cabin in hot weather, I found no other negatives in this category.
Quality and quantity for: Coordination; Authority; Pressures; Response; and Coupling.
Pros – Controls are exquisite on the Gull 2000; all Earthstar ultralights are good, this one is the best I’ve flown. Harmony was very good. Control range and authority are excellent. Very predictable characteristics. Control reach and feel were natural and pleasant. I’d say more but it begins to sound like an advertisement.
Cons – None. If you don’t like the way Gull 2000 handles, you may be too picky.
Climb; Glide; Sink; Cruise/stall/max speeds; Endurance; Range; Maneuverability.
Pros – The widest speed range I can recall in any aircraft; Beierle claims a stall of 26 mph – I could not accurately verify – and a Vne of 120 mph for an astounding 4.6:1 ratio (most designers would be delighted to hit 4:1). Climb rate is a breathtaking 1,500 fpm with the Rotax 503. Design also flies nicely at slow speeds. Can carry more than it weighs.
Cons – Honest, I tried, and I couldn’t come up with any performance shortcomings. Performance will be more modest if you stay within Part 103 (which is possible), as you must use a much less powerful engine.
Stall recovery and characteristics; Dampening; Spiral stability; Adverse yaw qualities.
Pros – Beierle calls his machines “stall- and spin-resistant” and I’d basically agree (though very aggressive use of controls could compromise this statement). Factory reports stall at 26 mph though I could not verify this fact; my stall experience was at 28-29 mph though this is still very slow. A beginner can certainly handle the Gull 2000 if he or she pays attention.
Cons – The Gull 2000 looks like it flies hotter than it does and this may mislead some buyers (though I doubt they’d be disappointed). Adverse yaw is present though it didn’t last long. Power changes cause minor adverse reaction. Longitudinal stability was slightly negative as is common on most ultralights with the engine mounted high on the airframe.
Addresses the questions: “Will a buyer get what he/she expects to buy, and did the designer/builder achieve the chosen goal?”
Pros – Is the Gull 2000 worth $15,000 to $16,000 plus options? You bet! This remains one of the best machines I’ve flown after sampling more than 250 models and I don’t say that lightly. It will also last well with its metal or painted fabric exterior covering. Wonderful flight characteristics for all experienced pilots and most beginners. Build time isn’t bad at 150 hours and factory offers help in a couple ways.
Cons – No wheel pants seemed strange on such a clean machine (but you can add them). Does not make Part 103 with the popular Rotax 503. Having it fully built costs $8,000 without finish paint (ultraviolet protectant is included). Payment must be in cash or money order; no checks accepted.
Donald Woeltje says
Where can I get an Earthstar Thunder Gull 2000?
Dan Johnson says
Contact Earthstar Aircraft for more info.
Bruce Vistad says
How can I get a copy of this article? My computer won’t print without ads that erase most of text!
Dan Johnson says
Hi Bruce: Sorry for the trouble you are having. Most modern browsers offer something called “Reader View” (often via a link in the URL line, though each browser is different). If you select that and then print or save as a PDF, I bet it will work for you. Good luck!