Mervin Zinck lives in New Germany, Nova Scotia. To put that in perspective, the town is a couple of miles farther south than the latitude of Bangor, Maine. (Interesting note: Maine extends farther north than does Nova Scotia.)
With the land wheels retracted above the floats, Zinck’s RANS is ready for the water.
Because New Germany Lake, located at the western edge of the village, is about a half mile from his home, Zinck had decided at the outset to fit his project with floats. He completed his RANS S-7S Courier—fitted with Full Lotus floats—in six months, and had it on the water in June of 2008. He built a hangar at the edge of the lake to take advantage of the location. He figured there was no sense traveling great distances to get to an airfield when only a minute or so would have him at the hangar. The Maritime Provinces are blessed with thousands of freshwater lakes, so there was no shortage of places to visit.
Like many homebuilders, Zinck is a craftsman in his own right. He owns a construction company that he built up from a single vehicle more than 30 years ago. One of his hobbies is the restoration of antique automobiles and farm machinery. He has the room, the tools and the skills to trade upon.
This tang allows both the retraction and deploying of the gear on its side of the airplane.
Preferences Change
While flying his S-7S off of water during his first 16 months Zinck discovered dozens of airstrips around Nova Scotia and the nearby provinces of New Brunswick and Prince Edward Island that he could land on—but only if he had wheels. This posed a problem. He had floats, which he would have to sell (probably at a loss) so that he could reinvest in amphibious floats in addition to incurring the extra cost of the retractable gear. Zinck wondered if it would be possible to convert his conventional floats into amphibious floats.
In February of 2010, he had an idea. He began drawing up plans for a set of retractable gear that could be quickly attached to the Full Lotus floats without too many time-consuming attachments or linkage points. By April he had come up with his own design, and the gear construction was completed. The rear wheels are fixed and self-castering, while the maingear is retractable and steerable with independent, hydraulically activated disk brakes.
This plastic hook simply shows the gear is up. It can be seen through either window. Pulling toward you when the gear is down brings it up. There is a hook on each side of the cabin, one for each maingear wheel.
Gear of Steel
The maingear is constructed of T1 steel. There is a channel bracket on each unit that fits over and sandwiches the outer longitudinal tubular stiffener on the top of each float. This is held in place by four quarter-inch stainless-steel bolts drilled through the channels and the stiffeners. Each is spread to keep the holes separated so as not to weaken the stiffener.
A transverse built-up, steel channel—welded to the outer stiffener bracket—spans the inner and outer stiffeners with a single bracket gripping the inside longitudinal stiffener. This too is attached with two stainless-steel bolts through the inner float stiffener. The outside stiffener takes most of the weight when landing. Because the channel and fastener are situated between the float struts, it is a secure hard-point area in which to attach. Any torque tendency when the wheel is down and bearing the aircraft’s weight would be offset by the cross channel and its secure position on the inside stiffener. In effect, the outer stiffener is being lifted, but that is offset with the downward pressure on the inner stiffener, all of which is in the short span between the main hull/float struts. It is very strong.
This close-up of the channel bracket, as it would be with the wheels in the “Up” (water) configuration, shows the sliding lock-down slot (far left) used to keep the wheels in the “Down” position.
This cross brace also supports the hinge upon which the gear struts swing up and down and under which slides the lock-down mechanism. When the gear is up, part of it sits right down in the channel.
The gear legs themselves are constructed of half-inch spring steel obtained from a local shop. They are bent to 90° and fitted with axles, rotors and disk brakes. The two maingear wheels are 6.00×6. Zinck used the bigger tires in anticipation of landing on grass strips and rough runways. Each retractable unit weighs 29.4 pounds. The two rear wheels, the cables and attachment bolts account for the balance of the weight, totaling 69.3 pounds.
Zinck’s floats might be marginally heavier than fully amphibious floats (he isn’t sure), but his can be detached at will, whereas integrated landing gear is in there for the long haul.
The maingear is right on the center of gravity and between the float bracing struts, and it’s at the strongest point. Zinck says that because his airplane is built to factory specifications, given the same airplane and same floats, there should be no need to fiddle with the location of the attachments on other RANS S-7S aircraft.
The maingear cradle bolts to the supporting beams on the Full Lotus floats. The pivot point is just above the outboard structural member.
Dear Operator
The gear is retracted by a cable. Once in the “Up” position, each retracted cable has a hook in the cockpit that hooks over a stud clamped to the tube airframe at the front of the seat. There is one of these cables on each side. The units are deployed using that same cable—a separate “pull down” cable is not necessary, because when the main cable is pulled up, the gear comes up and then goes over center and lies in the locked position. The tang on which the cable is attached is now angled downward. Pulling up on that cable lets it flip back over the center point and deploy outward. The gear is then locked down with the same cable that enables the locking mechanism. The locked-up and locked-down mechanism (a sliding latch) is employed for both positions. It is an ingenious system.
Zinck reports that he feels little weight when pulling each gear up, because once it reaches the over-center point, each falls into its retracted position on the float. He deploys or retracts one gear leg at a time—one hand to fly the airplane—so I asked him if the airplane slewed when he pulled one gear up or put one down. “Not really,” he said. “It’s still hanging out there in the breeze, so whether it’s up or down doesn’t make much difference.”
The rear float spreader was modified to strengthen and receive the tailwheel.
Coming up with a working braking system was a problem that Zinck had to overcome. Because the rear wheels are castering, in effect this is a taildragger on amphibious floats, and as a result, steering is accomplished via differential braking of the maingear. The connection of conventional brake lines on removable gear without the problem of having to connect the brake lines to a wet system that would require a laborious process of bleeding each side wouldn’t work, disregarding the fact that it is a messy business.
Zinck searched for and obtained connectors from a supplier in the United States. [Google “dry break couplings” to find suppliers near you.—Ed.] These allow the brake lines to be permanently filled with fluid and pressurized while the corresponding nylon brake line on each unit remains pressurized. When the nylon line is connected via a quick-lock to the male receptor on the fuselage, the little piston in the fuselage brake line presses on the receiver on the end of the maingear unit line; it transfers that energy to the brake fluid in the gear line, thereby activating the pads on the disk brake. Because both are sealed, there is never any need to bleed air—or fluid—from the line except when initially charging the brake lines during the construction process.
This is your downlock cable. It engages the sliding slot to make sure the gear stays down.
Speed Penalty?
When asked about extra drag, Zinck explained, “The turbulence coming over the front of the floats pretty much does away with that. The disturbed air doesn’t really leave much to create drag.”
He put 11⁄4-inch thick nylon shims under the two rear attachments on each float, raising the front of the floats and thereby increasing their angle of attack. He says it gives him a better cruise, because they are lifting rather than slightly hanging and adding drag. This also gets the tailwheels down a bit sooner during the landing flare. These are pneumatic tires held in place with a lock nut through-bolted through remanufactured tubing that was substituted for the original rear float spreader to strengthen it and to overcome any twisting moment or torque imparted during landings. The wheels are small enough that their drag potential in water is low when taking off. Zinck says he doesn’t even notice it, and because they are way behind the center of gravity, they don’t affect the touchdown on water.
At the rear of each float is a free-castering tailwheel. Note: This photo shows the wheel mocked up; we know there aren’t enough threads showing through the lock nut.
A “dry break” connector makes it possible to remove the wheels without having to open up the hydraulics.
The final wheel assemblies before installation. To improve flotation on rough ground, Zinck chose a 6.00×6 tire.
At time of this writing, Zinck had accomplished 66 takeoffs and as many landings with no signs of stress or fractures. “I overbuilt them to begin with for that very reason,” he said. On hard surfaces the rear wheels keep the floats clear of the pavement, while on grass they keep the float elevated; the Kevlar float bottoms barely notice the sod.
Zinck has it in mind to market his design and have the gear and attachments built under license by a local manufacturer. He hasn’t fully worked out the details, but he has registered the design. He can be reached at 902-644-2327.
Amphibian Hazard Reduction
Even when flying conditions seem auspicious, it can be easy to forget to select the proper gear position for landing.
We all know the adage. “There are two kinds of pilots: those who have landed with the gear up and those who will.” But amphibian pilots have it worse—because we have to get the gear right on every takeoff and every landing. “Ha!” people say. “How hard is that?” Hard, I say, because I’m one of those who got it wrong. One minute I was feeling good, about to smooch my SeaRey onto the riffles as smooth as can be, and a second later I was upside down underwater, trying to get out of my shoulder harness.
That was six years ago. The airplane wasn’t badly damaged, and it was flying again in a few months. But I was really spooked and have tried everything I could think of to keep from doing it again. For example, I always raise the gear immediately after takeoff now. I never make straight-in approaches to water landings, and I always check the gear before every turn in every landing pattern, reciting the amphibian pilots’ mantra: “This is a water landing, so we want the landing gear up” (or the land version for runway landings). I do look at the gear position before saying it.
ACI’s SeaRey Gear Alert kit (Model 2070A).
I’ve also tried several mechanical and electronic devices that help keep track of the gear position. Even so, I got a fright a couple of years ago, about 5 miles out of Dulles on what the controller had called “short final,” when I suddenly realized that I hadn’t even thought about the landing gear. A few months later I let a passenger distract me until it was almost too late to get the gear up for a water landing—this is after I had let him distract me enough during the takeoff from an airport that I forgot to raise the gear. That event really spooked me, because an expensive gear-warning device was flashing bright lights at me, and I had managed to ignore them. It was painfully clear that I couldn’t trust myself.
The Remedy
You select either Water or Runway landing on the alert system.
Fortunately, there is now a new device, ACI’s SeaRey Gear Alert (Model 2070A), which looks like it’s really going to immunize me from my own foolishness, because it checks up on me after every takeoff and before every landing, and it won’t give up until I get the gear position right.
Before every landing, when the flaps go to landing position or the airspeed drops below a preset speed, or both, this device requires me to choose whether this will be a water landing or a runway landing. A woman’s voice says, “Select landing” repeatedly, incessantly, and the “WATER” and “RUNWAY” lighted push-button switches on the instrument panel flash until I press the appropriate one. Then it checks the landing-gear position, and if I got it right, confirms my choice by saying, “Water landing, OK” in a woman’s voice or “Runway landing, OK” in a man’s voice. If the gear is in the wrong position for my choice of landing surface, the lights keep flashing and a very distressed woman’s voice cries out, “Check landing gear! Check landing gear!” until I make the necessary correction. It does the same thing if there’s an asymmetric gear problem.
Note that the SeaRey Gear Alert involves three of my physical senses and a decision. Lights flash, voices speak, I decide, and my hand responds by pressing a button. If it could blow perfume or skunk spray up my nose and squirt sugar or pepper into my mouth, it would do that, too. The Gear Alert watches me carefully after takeoffs as well. If the flaps are still down 30 seconds after takeoff, the Alert commences the landing sequence interrogation, “Select landing,” regardless of the airspeed. This is because it’s quite common to find land runways and waterways close together. If a pilot takes off from the water, for example, and wants to land on the grass, the gear must be repositioned immediately. Even better, after takeoff the Alert gives me about 30 seconds to raise the gear, and if I haven’t done that yet and if the flaps are up, the two lights flash and the woman’s voice says in the headsets, “Raise landing gear. Raise landing gear.” That may seem unnecessary, but in fact not raising the gear after takeoff is the most common serious error in amphibians. Almost every gear-down water landing could be prevented by heeding this reminder. I believe it to be the most important feature of the SeaRey Gear Alert, and no other such device has it. Now, to be honest, those nagging voices and flashing lights are annoying, and being required to press a button to make them stop is terribly annoying. But that’s exactly the point: They’re almost impossible to ignore. And for the device to then check your work and find it wrong is humiliating, but not nearly as humiliating as messing up the landing!
Lights flash in addition to a voice admonishing you to check the gear.
Proactive Voice Prompts
A subtler feature of the Alert is that the voices prompt you about what to do. Most other warning devices merely try to get your attention. I hadn’t realized how helpful proactive voice prompts are until adding Dynon’s AP-74 controller to the autopilot in my SeaRey. Prior to that I heard various “boop” and “beep” prompts in my headset and then had to figure out what they wanted. Airspeed? Altitude? Huh? They were all too easy to ignore because they required me to think, not a good thing when you’re busy trying to land the airplane or stay out of controlled airspace. The AP-74 converts the boops and beeps to speech, and that makes a big difference. For example, if I get too low, the voice says, “Altitude,” which is a lot more informative than “beep.” If I get too slow, I hear “Stall!” instead of “boop.”
The ACI SeaRey Landing Gear Alert goes even further by telling me what to pay attention to and what to do about it: “Check landing gear!” That’s better than an instructor whacking me over the head with a rolled up sectional chart. “Raise gear” reminds me to actually do that, so I don’t have to wonder what’s wrong. I need only comply, without losing my focus on something else. All warning devices should work this way!
False Alerts and Options
The SeaRey Gear Alert is designed to prevent false alerts. It keeps mum until the airspeed or the flap position indicates that the airplane is configured to land. But what if you’re doing stall practice or slow flight, or take off with the intention of staying in the pattern and shooting a few landings? No need to put up with the prompts. Just hold either button down for a few seconds and the Alert goes dormant until you tell it to wake up, or you turn it off and back on again. In that mode, there are no voice prompts, but the lights flash alternately to remind you to reactivate it before landing.
Input from SeaRey builders and owners was instrumental in making the Model 2070A effective.
Improving Fools
Nothing is absolutely foolproof, of course, but it would be just about impossible to ignore both the flashing lights and the voices of this device. Whatever distracted you that much would have to be so serious that the gear position probably wouldn’t matter anyway. My one wish for the Alert is that ACI would make the “Raise gear” prompt more insistent. It says “Raise gear” only twice, and rather mildly. I’d prefer it to repeat the command, perhaps at one-minute intervals, until the gear is finally up. Even so, it has already reminded me a couple of times when I was, ahem, slow to get the gear up.
The SeaRey Gear Alert is not inexpensive at $780, but I’m convinced (now) that it’s essential equipment not only for SeaReys, but for every amphibian. After searching for several years, I’m positive that no other landing gear position gizmo is as close to foolproof as this one is. And that’s because the SeaRey Gear Alert is the result of a collaboration of dozens of SeaRey builders and experienced amphibian pilots who worked with ACI to improve substantially what was then the best amphibian gear alert available. The company makes similar devices for other amphibians, including one for certified airplanes, but the certified version can’t monitor flap position, and they all lack that important “Raise gear” warning. For that reason alone, I’d recommend the SeaRey version instead, if it can be legally installed in your airplane. The ACI-2070A SeaRey Gear Alert will work just as well on retractable-gear landplanes, by the way, though it won’t enable them to land on water more than once.
For more information, visit https://store.searey.com/Default.asp
—Don Maxwell
Zinck’s RANS is now at home on the water and on the turf.
