Slipstream Industries’ Simple Scepter

SMILING BOB – Bob Grassl, a long-time ultralight veteran from Wisconsin, helped SlipStream display their aircraft for the camera.

LARGE SCREEN – The Scepter’s nose pod is a minimal affair but the large Lexan windscreen protects the pilot very well. Some runway debris can enter the cockpit, as the simple model has no floor.

PUSH PULL – SlipStream makes extensive use of push-pull cables using them for aileron and pitch from the yoke system, and for rudder pedals. Note adequate space on instrument panel.

WIDE TAIL – The Scepter felt very stable in the air, surely aided by this large tail surface. The cruciform shape pairs well with the engine thrust line to aid authority.

MOVERS & SHAKERS – These two men run the show at SlipStream. Company president Mike Puhl (left) runs the business while Graydon Gray directs action on the factory floor.

PLENTY OF ROOM – The Scepter cockpit may be perfect for larger pilots. Structure is simple but sturdy; SlipStream promotes the Scepter as a bushplane.

To many observers, SlipStream Industries is a different ultralight company. As they exhibit in the ultralight areas of big airshows, we know their heart is in the right place (as far as Ultralight Flying! readers are concerned anyway). But they also make twin-engine aircraft.
One way SlipStream distinguishes itself among all light aviation enterprises is by offering not one, but two twin-engine aircraft. The line-up includes the SkyBlaster, which was recently renamed Gemini Twin to differentiate the name from SkyQuest, SlipStream’s other twin. Gemini Twin is a rare fore-and-aft arrangement using two 50-hp Rotax 503 engines. Certainly it is the only one with this configuration in the ultralight field and it draws some analogy to the famous Cessna Sky Master. Hence its closely related former name.
Before the SkyBlaster/Gemini Twin, SlipStream developed and still sells another twin, the SkyQuest. Like its sibling, this twin aft engine pusher design uses the ultralight-standard 50-hp Rotax 503 dual carb as powerplants.
Enough About Twins
Okay, SlipStream is definitely into twin-engine aircraft and some larger-than-typical ultralights. And even if machines like the SlipStream twins are genuinely ultralight in spirit, they certainly don’t qualify as ultralights under FAR Part 103 or the Part 103 training exemption as they weigh too much.
The good news is that SlipStream also makes a single-engine 2-seater called the Revelation that does qualify under the training exemption. The Revelation is an opened-up Genesis (nose, floor, and windscreen but no aft cabin) which the factory will fully build, paint, and test-fly if used as an ultralight trainer. Add $6,000 for the ready-to-fly service and as far as I’m concerned, that’s an excellent deal and the way I’d buy a Revelation for training.
The company’s original model, the Genesis, is too heavy to qualify as a trainer under the exemption, though it does offer a fully enclosed light aircraft for those with valid FAA tickets. The Genesis and both twin models – Gemini Twin a.k.a. SkyBlaster and SkyQuest – are sold as kits. The same is true for the single-seat Scepter.
Of these many machines, SlipStream’s newest is the single-seater. We’ve worked our way through the SlipStream aircraft list to find one that I think most ultralight enthusiasts will like. Don’t get me wrong, the light twins are fun in their own way but they cost more than many ultralight pilots prefer.
SlipStream says the Scepter is “based on [our] popular Genesis design.” The company reports deliveries of more than 150 Genesis light planes, about 40 Revelation ultralight trainers, and 15 single-seat Scepters, as of late 2001.

The Scepter is the Wisconsin company’s version of an ultralight (but not a Part 103 ultralight. The Scepter’s empty weight is 425 pounds). It has clearly been built for simplicity and does not sport the full cabin of many other SlipStream designs.
Built from many lengths of 6061-T6 aluminum tubing and using sewn Dacron wings, the Scepter uses components of many U.S. ultralights. Like only the Golden Circle T-Birds line, the Scepter is available with either yoke or joystick, though I’ve never seen a joystick model. Evidently buyers like the yoke.
Back to Dacron
In a time when some designers are choosing dope-and-fabric coverings, Dacron is proving popular at SlipStream. Builders report that sewn envelopes are far simpler during the assembly process.
Covering aircraft with dope-and-fabric finishes carries certain challenges with it, most notably the need to paint the fabric. This can cost hundreds or thousands of dollars and the paint adds many pounds to an aircraft. It takes skill to make paint look as good as you see on airshow aircraft. On the plus side, it lasts longer.
Dacron wings that slip on have their challenges, too. Unless the designer works very hard to assure the right fit and finish, they can be tough to get on smoothly and tautly. However, they gain no weight from painting – you choose your colors before the seamsters start work. And though some builders have struggled to make surfaces like ailerons fit well, the job is widely considered to be easier than the entire dope-and-fabric process. In addition, no special facilities are required. Painting an aircraft demands a large, correctly isolated space with adequate venting (due to sometimes-toxic fumes).
Bob Grassl, a long-time aviation enthusiast with years of experience selling Quicksilver and other brands in central Wisconsin, is also a Bonanza owner, but this hasn’t changed his interest in ultralight flying. At last year’s Sun ‘n Fun airshow, Grassl aided the SlipStream team.
Grassl said the Scepter uses 4.5-ounce Mylarized slip-on wing covers that he referred to as “pillow cases.” He calls them “slip-on covers that replace the earlier dope-and-fabric covering, saving the builder loads of time and less weight when painting.” Grassl reports that the older material tended to distort more between ribs probably due to wider rib spacing and thinner fabric between ribs. His explanation offered yet another reason why Dacron remains a viable substitute for wing covering.
SlipStream president Mike Puhl reports that many customers are choosing Mylarized Dacron coverings. “Dacron wing sales are growing as a percentage,” he indicated at the end of 2001. Ironically, SlipStream provides dope-and-fabric materials as part of the base kit. The Mylarized wing adds $995 but saves the builder paint and paint prep materials, which will usually add up to be more.

 “The Mylarized Dacron shrinks well,” says Mike, and “tweaking the design patterns over time has produced a snug-fitting wing that is excellent as a covering.” He admits Dacron won’t last as long as painted fabric, but neither does it weigh as much. So back and forth, trade-outs occur and it may become a matter of personal taste or expediency. Dacron covering can be done much faster. For this reason, SlipStream will use Dacron on aircraft they manufacture as ready to fly.
Some may recall that three years ago (on January 4, 1999) SlipStream Industries bought the assets of Innovation Engineering. The Iowa company developed the Genesis and had worked on a single-place machine. Unfortunately Innovation Engineering owner Chuck Hamilton died while evaluating that machine.
 “However, we never even saw that aircraft,” says Puhl. It was deliberately destroyed after Chuck’s accident and the current team had no chance to evaluate it. Instead, the Scepter is a descendant of the 2-place Revelation which was modified from the Genesis. “In every way,” Puhl asserts, “the Scepter is our design and has nothing to do with Chuck’s single-seater.”
Big-Boy Bird
“We attract a lot of big pilots,” says Puhl. No wonder to me. Almost a design focus, this company has airplanes suited to those who don’t fit FAA’s 170-pound average pilot weight. That’s good; lots of ultralights aren’t too accommodating to large persons or those who have trouble entering compact cockpits. Chuck Hamilton, who gave birth to all the Genesis derivatives, was himself a large man. SlipStream developer Graydon Gray is also big, and it stands to reason they’d design to fit themselves.
Like most aft-engine ultralights, the Scepter sits on its tail when unloaded. A tailskid under the vertical fin keeps the tail from striking the ground.
Roomy as it is inside the Scepter, my legs bumped against the big bolts that hold the push-pull lines in place; I’d want to add some padding.
I could also appreciate a hand rest near the throttle. I hate to regularly focus on this, but it is my practice to keep my hand on the throttle nearly all the time, so this does become a comfort item. Especially for the half-hour it can take to shoot close-formation air-to-air photos, I am constantly working the throttle. A rest also helps steady your hand to make for more fine movements. At least the throttle is positioned where I could reach it easily, so the problem was lessened.
However, on a more general level, the Scepter has plenty of elbowroom and keeps with the open-cockpit theme of many popular ultralights.

Seated in the cockpit, you pull a single shoulder belt over your right shoulder. That allows a secure grip on the brake lever, mounted just at your left thigh. Pulling up engages both mechanical brakes that come standard with the base Scepter kit.
To your right is the throttle, so most will get in the Scepter’s cockpit from the aircraft’s left. Entering opposite this vital lever reduces potential problems. The brake lever on the Scepter’s left lies flat and out of the way when not deployed.
In front of me, like a Golden Circle T-Bird, Quicksilver GT 400, GT 500, or Aero-Lite 103 was a yoke. It gives the Scepter a certain “real aircraft” feel that may help sell a few to those pilots who learned in Cessnas or Pipers.
As you get ready to taxi, you notice the rudder pedals are firmly linked to the nosewheel. In fact, all surfaces have the solid, slop-free feel of push-pull cables that are used for all controls. The pilot can see (and visually check) the front-end fittings for all six push-pull cables. Redundancy is aided by having two elevator push-pulls to that critical surface, plus dual rudder push-pulls. Again, conventional pilots may like the look of these linkages.
Surprisingly Sprightly 447
With an empty weight of 425 pounds, you may conclude that the Scepter does poorly when pushed by the 40-horse Rotax 447 engine.
I would find out more aloft, but even on the ground, the plane didn’t feel as heavy as its numbers suggest and it seems ready to move at the touch of the 447’s throttle. Before I launched, I asked my checkout pilot, Bob Grassl, for some words of advice.
Grassl said that because of the complete lack of side area, the Scepter tends not to weathervane as much and therefore is better in crosswind landings. He admitted it did not also slip as well for the same reasons. The day was pleasant with winds mostly down the runway, but thermal activity was clearly present. And not only is the plane rather heavy, it also has a large wing. I was interested to see how it did in the bumpy conditions I knew were aloft.
SlipStream states, “The Scepter shares the exact-same 179-square-foot wing as found on the heavier Genesis and its offspring, the 2-place ultralight trainer Revelation. And because it shares the same wing, it can accommodate optional flaps to produce an incredibly short-field machine.”

I wondered if I’d need the flaps just to lift off in the big machine with the “small” engine. No problem.
With perhaps 12 mph of close headwind, the Scepter readily dashed off the ground. Without a tape, I couldn’t measure exactly, but my feeling is that I was airborne in less than 100 feet. I was surprised at the ease with which the Scepter got to flying speed. Nothing like a big wing to help.
No way around it, handling is largely a personal preference. Any modern ultralight has reasonably good handling so what makes one seem better than another depends heavily on who is flying. For me, yokes don’t get it in air sport planes, but the good news is you can have it either way from SlipStream. Since the test aircraft was yoke-equipped, I may have perceived it differently than if I’d had my hand on a joystick.
Roll was reasonably responsive, perhaps creating 3- to 3.5-second reversals from 45° one way to 45° the other. Some planes are faster, but many are not.
As much as anything my airborne notes remembered the good harmony. Use of the controls could be done in roughly the same proportions. This quickens familiarization for any pilot and never needs to be remembered. Many ultralights require you to lead with the rudder or use it sparingly in some turns.
My 720° steep turns at a 45° bank angle went fine in the turn. The Scepter is more than willing to hold a turn with little input, which makes the maneuver easy to accomplish. However, my roll-outs were inconsistent, sometimes off 30° from my chosen heading. This is important at times like low turns to final (of course, a good pilot avoids such last-minute planning).
Perhaps the sensations I recorded had something to do with a stiff movement in the yoke. I primarily noticed this as it relates to pitch movements; I couldn’t perceive any effect in lateral controlling though such a sensitive touch doesn’t come in the first hour of flight.
I was annoyed by the pitch dynamics in the Scepter. When I nosed it over it would keep going. When I raised the nose it would keep going. True, it was a vigorously active thermal day; at one point while flying level I rose 300 feet in a single thermal bubble without turning, rare even for thermally laden Florida. Yet another pilot who flew the Scepter the same week I did referred to this same pitch quality of the Scepter as “elevator float.”
About a month after my flight, I visited the factory and asked plant manager GraydonGray about it. He knew the problem and said an incorrect lubricant applied to the yoke shaft where it slides into the panel supports caused it. He says it got sticky in Florida’s heat (compared to a chilly Wisconsin where it was applied). He feels this prevented smooth movements. Perhaps, but I’d like to fly one properly lubricated to experience the difference.

Perhaps because the Scepter’s ailerons are reasonably responsive, the single-seater exhibited significant adverse yaw.
I asked people inside and outside the company for their justification of no interplane or jury struts on the wing struts. Such parts add little weight, cost, or complexity, yet they are missing on the Scepter. SlipStream and some nonaffiliated designers felt the size of the wing strut tubing parts were sufficient for them not to be needed. Nonetheless, I’d have felt better with them.
Big Wings, (Relatively) Low Power
The Scepter’s good news, maybe its great news, is that the single-seater performs quite well on a 40-hp Rotax 447. Its large wing chord no doubt contributes to this.
Published factory figures claim a 12:1 glide. Original developer Chuck Hamilton was associated with Challenger manufacturer Quad City Ultralight Aircraft as that company got started. The Challenger’s wing is also revered for its glide and sink performance, so the Scepter’s ability in this area comes without surprising me. However, 12:1 is pretty ambitious for an open cockpit aircraft; the best hang gliders perform only a little better than this. I’d like to measure these things myself but good glide angle numbers are difficult to assess. Timed descent sink rate figures are easier to obtain.
Since the Scepter uses the same 179-square-foot wing as used on the 2-seat Revelation trainer and the larger 2-seat Genesis, it seems logical the single-seater has an improved sink rate. Compared to all other models in Ultralight Flying!’s Ultralight and MicrolightBuyer’s Guide, the Scepter has one of the largest wings for any single-seater.
You may have read earlier published figures stating the Scepter weighs 360 pounds and has a paltry climb rate of 200 fpm. Puhl says these numbers applied to the prototype, which used a shorter wing and smaller ailerons plus different tail feathers. However, early in production planning, SlipStream realized it was not cost-effective to keep a second set of parts in stock. So the Scepter got the Revelation wing.
The Scepter’s 179-square-foot wing is large by comparison to the majority of single-seat ultralights. In fact, UF!Buyer’s Guide 2001 shows that only one single-seat ultralight had a bigger wing. That was the Dragonfly, a hang glider tug with an especially large wing to accommodate slower-flying hang gliders on tow. Even then, the Dragonfly only had 1 square foot more. Generally, biplanes also have greater wing area. The range in the UF! Buyer’s Guide 2001 is 95 to 180 square feet with the average roughly 150 square feet.
All big-wing aircraft have several attributes in common. They generally fly more slowly and they often exhibit better sink rates. Helpful on approach, this often translates to better glide angles as well (depending on drag produced by the design).

If handling doesn’t suffer by becoming slow – and it does not on the Scepter – then a bigger wing can give a smoother ride. Big-winged designs generally stall slower with less abrupt characteristics. They can carry more weight.
The downside to big wings and the big Scepter is fuel consumption, but SlipStream again has a solution. The Wisconsin bunch is now the U.S. distributor for Zanzottera engines (once imported by Canada’s Aircraft Sales and Parts). Puhl recommends the MZ 201 with 45 hp at 4,700 rpm. It’s lighter than a 503 by quite a few pounds but uses a belt drive to the Rotax’s gearbox. The MZ 201 sells for a just over $3,200, which is a few dollars more than a Rotax 503, but the Italian engine includes electric starting, making it quite economical.
Caught by a SlipStream?
SlipStream describes the plane used for this “Pilot’s Report” as: “Beautiful red-and-white Scepter featuring SlipStream’s all new Mylar impregnated flight surfaces. Low-time Rotax 447 engine and 2-blade wooden prop. Panel is outfitted with an altimeter, airspeed indicator, tachometer, EGT gauge and CHT gauge. Engine and prop have approximately 40 hours total time, while the airframe has less than 20. This Scepter has a BRS 750 VLS chute installed.”
The company offers this description because the test Scepter is for sale. SlipStream is asking just over $15,000 for the built but somewhat used Scepter with good equipment installed. A new buyer would pay $11,000 for the airframe kit, say $5,000 to have it built, around $3,600 for instruments and a BRS for a total of just over $20,000.
The Scepter’s base price is a modest $10,995 including the Rotax 447 engine and wood propeller but no paint or instruments. If you prefer to move up to the 50-hp Rotax 503, SlipStream will sell you the more powerful model for $12,595 with the E gearbox (which can add electric starting). But the company is keen to move buyers to the Zanzottera engine that they import. It does have some positive attributes like good power at light weight, modest cost, and standard electric starting, though some buyers won’t want the belt-drive system.
SlipStream’s option list goes on for some length. Check the Internet or call the company for details and prices. “Virtually all of the many Genesis and Revelation options are also available for the Scepter,” says SlipStream.
SlipStream has already investigated fully manufacturing aircraft and has delivered 8 Revelations completely finished at the factory. Puhl is enthusiastic about continuing this plan.
Manufacturing is a double-edged sword. It brings in new funds to manufacturers who can always use more. But it opens new problems (more personnel, facilities, and funds are needed, for starters).
If you have a valid FAA pilot’s certificate and can tackle at least the Scepter’s Quick Build version, you can have a solid single-seat ultralight-realm aircraft that will handle the biggest guys. That such a big ship performs well with the 40-hp Rotax 447 speaks well of the general design.
Grab a Scepter for yourself and see if doesn’t make you king of the air.