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SEAMAX vs Super Petrel?

It's important to choose the aircraft that fit's your needs the best. When it comes to choosing between SEAMAX and Super Petrel, Bob Schwartz is the one to ask--he owns both! He wrote the following article to help you choose.


I own two different Light Sport amphibians - a Seamax and a Super Petrel. I thought that I would compare the two aircraft to give prospective buyers an idea of the differences - at least from my perspective.


My Super Petrel is a 2021 Series 400 with a Rotax 914UL, and is kept out West in northern Arizona and Montana. The Seamax is a 2018 FW (Folding Wing) with a 912ULS, and is usually kept in southern Florida. I did bring the Seamax to AZ during the summer of 2019, so I have experienced both planes in the same environment.


To make a buying decision easier, if you want or need to have a folding wing amphibian, then your only choice is the Seamax, who make a folding wing model as an option.


That is, unless you don’t care about performance or load capacity, and don’t care about value for your dollar, then you could buy an Icon A5. And if you plan to unfold/fold the wings for almost every flight, and you fly alone most of the time, I would seriously consider the Icon. The Icon’s wings fold easily and quickly, with no hassle or disconnecting of controls. It’s simplicity in folding cannot be beat. It does lack in carrying capacity, and other performance specs, so you should do your own due diligence.


The Seamax requires some disconnecting of controls and it also requires an external wing support structure to be brought to the plane and attached to hold the folded wings in position. It takes me about 15 to 20 minutes at a leisurely pace to fold the wings of the Seamax to prepare it for towing. If I need to drain fuel to get below 1/2 tanks (required to keep from leaking fuel), then that time is additional.


If you want or need a turbocharged engine, then the Super Petrel is your only alternative, as currently, Seamax only offers the 912ULS. (I have recently been told that Seamax is working on offering the 914 in the future, so stay tuned).


Out West, I fly at density altitudes that typically run 6,000 to 8,000 feet, so I ordered the Super Petrel with the optional turbocharged 914UL.

The 914 is very nice to have at these high density altitudes. Although when I had the 912 Seamax in AZ, it did perform satisfactorily at its max gross weight of 1320 pounds.


Aside from the above considerations, I will now list the many differences between the two planes to give you a feel as to which ones might be important to you or which ones might be areas for your further research. The factory sales people can update you on the status of some of my “complaints/observations/opinions,” to see if there have been any changes since my purchases.


INTERIOR -


For my taste, the Seamax looks more finished with its carpeting and leather side panels. The Petrel has a utilitarian speckled fiberglass finish inside.

The Petrel’s seat belts are a bit more difficult to use. And the belt enters the cabin through an unfinished slit in the vinyl - not very attractive.

The seats of both aircraft are comfortable for long flights.

The Petrel has more, and more user friendly, cabin storage space. It has a shelf midway up the rear bulkhead which is very convenient.


PREFLIGHT -


The removal of the full Seamax cowling and just the top cowling of the Petrel are similar in difficulty. The Petrel does have an access hole built in for checking the oil, so that top cowl removal is not necessary for this function. During preflight, I still prefer looking at the whole engine and checking the coolant level, which means removal of the top cowling in the Petrel to give access to the coolant tank (and the top spark plugs). To access the bottom plugs and oil filter of the Petrel, the lower cowling must be removed. This cowling is so difficult to remove, that it probably won’t be removed except by those wanting to use their 4 letter swear words - and use them often.


FUEL SYSTEM -


The Seamax is the winner here. It is easy to sample the fuel, see the fuel levels, and it’s easy to switch tanks. The Seamax has an on/off valve at each wing tank, and a plastic tube that shows the fuel level from the cockpit. You can’t get any easier or simpler than this. In the Seamax, you know a tank is empty when the low fuel light comes on in the header tank when it stops being supplied with fuel from the wing tank. Then you can switch tanks, knowing that the previous tank is completely empty.


The Petrel uses a unique fuel sampling procedure that requires turning on the Master, opening the fuel cock, and then reaching into the cockpit to push a fuel drain pump for the sample as you reach to hold a container under the drain outside. The Petrel has a more difficult fuel system to use and monitor while flying. The “Main Tank” is a 4 gallon plastic header tank located behind the passenger seat. The level is checked visually, which is difficult when using the recommended auto gas, which is close to the color of the tank and is partially covered by the storage shelf. When a tall passenger is aboard and the seat is all the way back, visually monitoring the fuel level and switching tanks is VERY difficult. The wing tanks drain into the header tank via a difficult to use left/right switch on centerline and behind the seat backs on the floor. The wing tanks fuel level is “monitored” by a float sender in the header tank that reads out fuel levels on the Garmin G3X . But after switching tanks, you have to wait several minutes for the fuel level to stabilize in the header before you get an accurate reading. The only way you can confirm that a tank is empty, is by waiting for the fuel level in the 4 gallon header tank to start dropping, and then you can switch to the other tank. There is no low fuel light in the Petrel to act as a reminder.


INGRESS & EGRESS -


The Seamax is the winner here, in my opinion. The Petrel requires you to step on the seat and let yourself down around the stick. The Seamax allows you to step on the floor and it has a center stick, so you don’t have to work around it. (Neither plane is easy for those with weak leg and arm muscles, especially when exiting). The seat adjustment in the Petrel is a bit easier and quicker. Simply lift the seat back up and reposition in slots fore or aft. The Seamax requires removal of the seat cushions, and then pulling pins to reposition the seat.

The seat back angle is adjustable in the Seamax. It uses a sliding tube with a push pin to adjust to various holes in the outer tube to give you different angles.


BALLAST -


Definitely much easier in the Seamax. It has a 14 pound lead ballast that is used when flying solo, and it can be removed in seconds, (and kept aboard if required). The Petrel requires a pilot and passenger with a combined weight of less than 210 pounds to use 44 pounds of ballast, which consists of 5+ gallons of water in a tank accessible from a hatch in the bow. That’s a lot of weight. To remove ballast, the water is drained into the hull and then pumped out with the bilge pump. Finding 5 gallons of water at an airport is not always an easy or convenient matter. So switching between solo and carrying a passenger is much more difficult in the Super Petrel and requires a bit of planning. (Depending on the weight of you and your passenger, you also might have to partially off load some portion of the water ballast).


WATER IN THE HULL -


For both planes, the use of only the bilge pump will still leave around a gallon (8 - 10 lbs.) of water in the bilge that can move fore and aft depending on attitude. I prefer to fly without this movable ballast, so I like a dry bilge. The Seamax’s bilge is easy to check via two screw caps on the outside of the fuselage, although bilge visibility is not possible from inside the cabin. External access is simple and easy. Any water that the bilge pump doesn’t remove can be pumped out with a hand pump and sponged dry prior to flight while on the ground.

The Petrel has no bilge access. To remove all the water from the bilge, so you have to hand pump it out from the inside through a tiny slot around the landing gear Johnson bar using a small tube attached to a hand pump. To get a completely dry bilge, you have to push a cloth through the slot opening and then fish it out - a difficult task. An access cover inside the cabin would sure be nice!


The Petrel also takes on more water in the bilge when it is in displacement mode or beached or moored on the water - even if I am solo and not near gross weight. The sealing of the landing gear does not seem to work as well as that of the Seamax. Something else to consider: If you are keeping your plane outside, removing all the water becomes an issue. Any remaining water will steam in the sun and cause mold and mildew. Both airplane canopies will leak a bit during rain, so total water removal can be important if your plane is primarily tied down outside.


CANOPY OR DOOR OPERATION -


The Seamax has a canopy that can be left up for taxi, or left ajar about 4 inches by using a built in support. The canopy is locked closed via a lever actuated pin on each side. The visibility is unsurpassed from the Seamax. The Petrel has doors that can be removed for flight. I removed the doors a few times, but it was quite noisy and breezy. It’s certainly a nice option to have, but doesn’t particularly suit my taste. The doors can be opened for taxiing by folding them forward (watch out for gusts). The Petrel’s doors have a center lock and side locks that are not easy to use. The lower side locks have occasionally worked their way to the unlocked position. The visibility from the Petrel is very good, but it’s hard to beat a full canopy in this regard, although the sun can be a bit more problematic in the Seamax. Neither aircraft have been a problem for me as far as the cockpit getting hot - even in Arizona and south Florida. The vents seem to provide adequate cooling air even on hot days.


STARTING AND TAXI -


The Petrel’s choke is a bit harder to access and to make sure that it returns to the off position. It requires you to reach behind a portion of the bulkhead and up on the ceiling to pull the choke. They both taxi about the same, with a free castoring nose wheel, although the Petrel’s nose wheel doesn’t rotate as easily as that of the Seamax. The Petrel has fixed position heel brakes, which I personally find more difficult to use; if I’m pushing the rudder pedal to the max, it’s hard for me to get my heel back to the fixed brake at the same time, so it’s pretty much rudder OR brake. The Seamax has conventional toe brakes that move with the pedals. The quality of the braking is similar in both aircraft; that is to say, marginal. A Berringer brake option would be something that I would definitely get if offered; unfortunately, neither manufacturer offers it at this time.


LANDING GEAR OPERATION -


Again, the Seamax wins with their electrically operated gear. The gear can be extended at any airspeed. The Petrel uses a Johnson bar that requires an awkward movement of the hand and arm and is not real easy to operate. The airspeed must not exceed 70 kts for extension or operation while extended. I was told this is because of the security of the nose gear doors. The position of all three gear can be seen via mirrors on the sponsons in the Seamax, whereas the gear in the Petrel is unable to be seen from the cockpit; their status is confirmed by an indicator on the G3X and the position of the Johnson bar. Also, the Petrel is not available with a parking brake. I use the parking brake on the Seamax a lot, and I find the lack of a brake on the Petrel an irritation.


FLYABILITY and USER FRIENDLINESS -


A mixed bag here, but here we go:


*The Seamax has an irritating yaw (fishtailing) movement while flying. It requires more attention, but can be coped with after some practice.

*The Seamax also has a heavy feel to the elevator. The stick cannot be released during gusty conditions, because the elevator will take off on its own. The Petrel doesn’t exhibit these characteristics and flying with the hand off the stick does not present any issues.

*The Petrel is much more sensitive to pitch changes with changes in power. This is especially noticeable when taking off from the water in a go around situation. The Seamax pitch changes are minor when changing power settings.

* Coolant temperature monitoring on the Seamax is much more critical. The coolant can go into the redline with extended taxi or ground operation. I’ve had to shut the engine down to let the coolant cool while awaiting take off clearance. The Petrel seems to have the coolant temps under much better control.

*The Petrel has a much higher sink rate, and a steeper glide ratio, no doubt due to the extra wing and struts. This is generally not a plus.

*The Seamax with the 912 cruises about the same 100 kt speed as the Petrel with the 914, but at around a 2 gal per hour extra fuel burn penalty in the Petrel.

*On landing on water, the Seamax takes longer to come off the step. When I mentioned this to Seamax, they suggested dropping the gear after water contact to ensure a short landing distance in a confined area - something I haven’t needed to try yet. The Petrel doesn’t exhibit this trait, and comes off step reasonably soon.

*The Petrel feels a lot more comfortable making sharp turns on the step to keep in a confined area. I’ve been able to turn some very tight circles. I’ve been told that even if you spin out, there is no damage. I did spin the Seamax once, and took off a sponson and did minor damage to the wing tip.

*The Seamax has electrically operated flaps, and in my experience, lands at a slower airspeed, even though the published specs claim the Petrel has a 2 kt slower stall speed. The Petrel doesn’t have flaps.

* Both aircraft have similar stall characteristics. It’s more of an increased sink rate rather than a break. Recovery on both is very easy with little loss of altitude - just lower the nose and/or add power.

* They both have an effective elevator trim on the stick.

*The Petrel comes with an aileron trim.

* In my experience, they both have similar take off and landing performance. The gross weight for both is 1320 pounds for water operation. The Petrel increases its gross to 1450 for land operations, which is a very nice feature! The empty weights for both are similar - around 825 lbs.

*I like the flat area on the dash of the Petrel; it makes wings level step taxiing much easier. The Seamax has curves in all three axis, so it makes step taxiing and lining up with the runway centerline more of a challenge until you gain a little experience.

*Control authority and response seem to be similar, although the Petrel stick hits against the seat cushion in full aft stick, which requires extra effort for full deflection - an easy fix that could be made by the factory (hint).

*Water handling goes to the Petrel. As mentioned, the Petrel turns a lot sharper than the Seamax on the step. In displacement mode, they are pretty comparable. The Seamax has a water rudder, but not the Petrel. For my type of water maneuvering, I don’t require the precision that a water rudder gives. If you plan to dock or maneuver in more confined areas with crosswinds, the water rudder might become more important to you.

* The Petrel’s lower wing protects the propeller from water spray when transitioning onto the step. The Seamax’s prop can be heard to hit the water spray upon transition to planing - although in 3 years, my composite Sensenich prop with a metal leading edge has shown no wear, except for some paint removal.

*The Seamax has a “water in hull” light that I feel is an important safety feature; the Petrel does not.

*Likewise, the Seamax has a low fuel warning light, but not the Petrel.

* The Petrel doesn’t have any padding for your elbow as it rests at the throttle - it rests directly on the fiberglass. I find this to be irritating after a while.

*The Petrel has tie down rings to aid in tying the plane down on the ramp. The Seamax does not - a rope must be tied around a strut.


GEAR DOWN WATER LANDING -


There are a couple of YouTube videos that show both planes landing on the water with the gear extended without flipping over. The Seamax is designed with a breakaway nose wheel, so after the “landing,” you’ll have to land on the belly and buy a new nose wheel - a lot more hassle, but better than flipping upside down. The Petrel appears to be able to still land normally after the mishap, a major plus for those who forget to use their landing check list.



MAINTENANCE -


The top cowling on the Petrel and the complete wraparound cowling on the Seamax are similar in difficulty to remove; that is to say, not easy, but doable for one person. The problem arises when you try to remove the lower cowling on the Petrel for an oil filter change, or to access the lower spark plugs. At least in my Petrel with the 914, the air filter and exhaust pipe need to be removed, and a second person to help is a must. The radiator has to be removed, and is held in place by some funky hard to reinstall plates and pins. I would rather do 4 oil changes on the Seamax than do 1 on the Petrel. I feel that the Petrel lower cowling should be made into 2 or more sections to aid in removal (hint). The Petrel uses standard fuel lines. The Seamax uses plastic tubing. Although I’ve not had an issue in 3 years with the Seamax, a standard fuel hose gives me a greater sense of security than a plastic tube. The additional extra wing on the Super Petrel does add extra work for bug removal, washing, and waxing.



SUMMARY -


Major likes:


Seamax:

* Everything is convenient, easy to use, and well thought out.


Super Petrel:

* I love the water handling when on step. It’s a real blast!

* I like the feel of the plane when flying.


Major gripes:


Seamax:

* Having to closely monitor the coolant temps on the ground or water so as to not overheat.

* (FW Option): The need for a large heavy structure in order to fold the wings. Makes wing folding only possible at your home base.


Super Petrel:

* Difficult to use ballast system.

* Difficulty in removing bilge water and no bilge access.

* Difficulty in removing the lower cowling.


Minor gripes:


Seamax:

* “Fishtailing” during cruise flight.


Super Petrel:

* Complicated fuel system and difficult to operate fuel tank switch; VERY difficult to monitor and switch when passenger seat in rearmost position.

* Water leaking into hull in displacement mode or while beached or moored.

* Awkward Johnson bar movement to operate the landing gear, and airspeed limitations of gear.

* More difficult ingress and egress.

* No parking brake.


Overall, it’s a tough call.

I feel that the Petrel has the edge in handling in the air and on the water.

The Seamax wins in virtually all other areas of user friendliness and accessibility.


Both aircraft are a ton of fun to fly!!!

I don’t think you would make a mistake buying either amphibian. It comes down to the Ford vs Chevy argument. Which of their features are the important ones to you? I hope this has given you some thoughts and ideas and things to consider in your investigation in making your decision.


Editor's note: I added a second trip tab to my rudder (allows for a shallower bend in the trim tab for the same effect)--this combined with the yaw damper that comes with the autopilot have minimized fishtailing. Both manufacture now allow 1430 pounds gross weight while operating on runway's (which is very helpful for carrying gas on cross countries).

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During my 40 years of flying, I have always wanted to own an airplane. Over the years, I have looked at a number of airplanes, but I was never able to take the plunge and write a check. There are plen