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Best Homebuilt Amphibian

Posted By:
Brad Strand
Homebuilder or Craftsman
66
Posts
27
#1 Posted: 8/14/2009 05:59:31

What do you think is the best homebuilt amphibian?  I have not seen a comparison of the different amphibians and would like to hear which one you think is the best.



Doug Belbin
Homebuilder or Craftsman
8
Posts
1
#2 Posted: 8/15/2009 20:52:11

If you are happy to build from plans look at the Osprey, Google it and on the web and drool over some beautiful examples. A friend of mine has just bought one.

Add an Aussie Jabiru 120 hp engine, and get an extra 100 lbs load and overhaul costs are 25% the Lyconentals..

 

If you need a kit the little Searey takes a lot of beating.

There too if you fit an 80 horse direct drive Jabiru, overhaul is a LOT lower than the geared expensive Rotax.

My 2 cents



Doug & Lisha Belbin - Yippyio on Vans wings - Australia - http://www.yippyio.net
Reggie Smalls
Homebuilder or Craftsman
126
Posts
49
#3 Posted: 8/16/2009 11:46:34

An alternative to the Osprey for a plans built amphib is the Anderson Kingfisher. 



Brad Strand
Homebuilder or Craftsman
66
Posts
27
#4 Posted: 8/17/2009 00:31:57

Here is an interesting link to a page full of amphibs. 

http://www.flyingboats.ca/PurchasingAFlyingBoat/



Jesse Schoolcraft
83
Posts
20
#5 Posted: 8/17/2009 22:38:04

There's a guy at KMWO here in Middletown, OH that built a Murphy Rebel on floats. I don't know how he likes it, but just thought I'd throw it out here.



"Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--- Leonardo da Vinci
Richard Rabe
2
Posts
1
#6 Posted: 8/19/2009 20:36:32

I've been flying as Osprey II with a 150 HP Lycoming for many years.  Its alot of fun, but takes off and lands around 80 mph.  I added VGs to the wings and underside of the tail.  They seem to help alot.  Its for sale.  Too many toys. RERABE@aol.com



Martin Stentzel
8
Posts
5
#7 Posted: 8/20/2009 01:13:47

 

Hi Brad,

I carefully compared different experimental-category, 2-place plans-built designs -- mainly the Osprey, Coot, Kingfisher and even a basic (180hp) Spencer Aircar --  and kept coming back to the VJ-22 Volmer Sportsman. They are all proven designs and each has its advantages but for me the -22 seems to have the edge in the ways that are important to me.

So let me count the ways:

The Aircar is just more plane than I need or want to spend for. Although I fondly remember a friend’s SeaBee I also enjoyed sitting low on the water in the Buccaneer I got my rating in.

On the other hand I think the Osprey falls short on the practicality scale. I looked at one up close and it seems like a very well designed bird but too tight, even claustrophobic to me, and no room for baggage. The VJ has the most potential room for camping gear. The Osprey has almost no freeboard – looks like you’d better keep that canopy closed and watertight if any wave at all comes by. It has a higher stall speed and seems to need more horsepower (like the Coot) to get by, and doesn’t seem to be a good back-country plane. It is faster too, but for me I’ll trade some speed for more utility.

The Anderson Kingfisher is most comparable to the Sportsman. I’m not sure about Kingfisher plans availability, but I think so many more folks choose to build the VJ for the same reasons as I; much better visibility, (I think the Kingfisher is tandem seating? I’d prefer side-by-side and wider baggage area), easier entry/egress, more freeboard to the door. I think Mr. Anderson was trying to lower the thrustline compared to the -22, but I don’t think it’s the problem it might seem; at least it wasn’t in the Lake. I do like the Kingfisher’s Cub wing better than the Aeronca wing of the Sportsman plans but guys have used Cub and other wings for it too.

The Coot is an interesting design and has its selling points, but for me the Coot’s advantages turn out to be more theoretical than real (no wing struts or floats, lower thrust line), or not that important to me (tri-gear level on ground, wider cabin, folding wings -- which could be incorporated in the VJ). Whereas the Sportsman seems significantly simpler/cheaper to build, same performance on 2/3 the horsepower (cheaper engine and operation; I think weight and dihedral kill a lot of performance on the Coot), and a larger potential baggage area.

For a kit-built the only one I’ve seen was a SeaRey. My ruminations are that compared to the VJ-22 it’s almost the same empty wt. (slightly lighter), useful load (VJ a little better), horsepower, speed, etc. The Volmer design is larger overall (more steady in flight) and has more potential for ideas I have (larger baggage and other things too many to list here), has more panache with its wood (one good look at a nice wood homebuilt – that Osprey – and I fell in love), is better looking with its classic lines (I’m a sucker for antiques) and waaaaaay cheaper (like half). The SeaRey is a little wider at the seat, has lower sides (easier to get in/out but less freeboard), and maybe shorter TO/landing (I have some ideas to help that, not that it’s bad as is). As a kit it’s faster to build (650hrs. vs. 1500hrs. according to Jensen and others in Sport Aviation articles) but then it’s the same as every other SeaRey out there. And that Rotax may be a good engine but I just don’t like the sound compared to a direct-drive.

Okay I’ll shut up. Just after I say you might want to read the Sport Aviation articles on the VJ-22 archived online here. I thought they were interesting, and then of course there’s the Volmer Sportsman website and forum too.

 



Brad Strand
Homebuilder or Craftsman
66
Posts
27
#8 Posted: 8/20/2009 09:29:49

Hey Martin, that was a great reply!  I can see that you have put a lot of thought and research into amphibians.  I appreciate your taking the time to tell us what you have learned.



Martin Stentzel
8
Posts
5
#9 Posted: 10/26/2009 19:04:30

 

Brad,

You shouldn’t encourage me like that. But just to ruminate some more, this time on an Anderson Kingfisher which I recently looked over and talked to the owner (not the builder) about. First I want to say that while I have developed some opinions I’m not saying others shouldn’t have different ones; whatever wets your whistle you go for it, that’s what homebuilding is all about.

From my perspective the Kingfisher has one main advantage over a Volmer Sportsman– about 1.5 ft lower thrust line. The owner says power changes do not affect pitch up or down. Also, the seats are side-by-side, to correct my earlier post.

On the other hand I think of several cons;

1)    Your eyeballs are at about half cord under the wing so visibility changes from one of the best with the VJ-22 Sportsman (and others) to one of the worst. The wing floats are half floats or you’d have no vis to the side, and the nose is way longer so vis ahead is also worse, especially I’d think when taxiing onto the beach while trying to steer around obstacles.

2)    Entry/exit is more difficult even though the seat height is lower than the VJ because you have to come in from behind the wing, ducking under the trailing edge and squeezing through the small clamshell door. Freeboard is less – about one foot according to the owner to the bottom door half, which may be fairly watertight when closed. Just avoid trying to get in/out while in shallow water if the door is towards any surf. Also no standing up in your seat -- in boat mode -- to check ahead for submerged logs or rocks, throw a line, etc. (The Lake Buccaneer was great for that. I’d design my VJ canopy to allow it.) How you could get out on a dock I can’t imagine.

3)    There is less potential baggage area behind the seat and greater CG concerns of the baggage weight. Picture a VJ if you relocated the seat behind the step up against the rear spar bulkhead. Of course you could possibly make another baggage area in that long nose to balance it out.

4)    The owner says his empty wt is 1200 lbs with a high-compression 0-235 and metal prop. He thinks his plane was overbuilt. Kingfishers have a deeper vee hull than Sportsmans; maybe a nicer ride but he has a hard time getting on the step. He’s played with various props, added 4 inch spray rails, hull strakes and installed vents behind the step, and still can’t takeoff a 1000’ AGL lake by himself (I’d say he’s 160lbs) on a hot day. He’s thinking of going to a 0-320. I don’t know but I wonder whether having that blunt windshield immediately behind the prop in part of the most important area of the prop disk could have an effect on performance. He said he cruises (at 2600rpm) at 75mph (yes that’s what he said); of course I don’t know how accurate his ASI is but to me that is really slow.

 

Other observations;

1)    The tailwheel rotates sideways to retract, a la Seabee and is free-swiveling with a lock. Interesting, although I like my idea for t/w retract better. It does let the air rudder extend lower than a Sportsman with a separate water rudder dropping out of the air rudder like a Lake has. Just wondering whether that sideways wheel is still dragging a little in the water while climbing on the step?

2)    The wings are Piper Cub. One thing I am personally partial to, but could be used on the VJ-22 if you really wanted (and I do).

3)    The main gear is independent, left and right. There’s no crosstube because your legs are in the way, so you retract each side individually. This means that the gear bulkhead has to be extra-strong -- I think building this way ends up being a little heavier, and of course you can’t have the gear rotate up and around to the rear with the doors there, which can help getting on the step in a Sportsman.

4)    You climb onto the nose to access the engine. I think I still like my idea on the VJ-22 of reinforcing the turtledeck to walk up the tail.

5)    I think in certain conditions you’d get a little more spray through the prop than either tractor or pusher VJ. Just guessing. There’d be at least some propblast at the cabin; I like the Lake/VJ and others that have the prop really up out of the way.

 Well, you did ask for folks opinions. I’m sure others have some different ones. The VJ-22 isn’t perfect. I think some state-of-the art composite designs on the net could be better in some ways. They look sleeker, if that’s important to you. They’re also more expensive and may be unproven. We all have our design preferences and mission priorities, budgets and construction aptitudes but for me ol’ Volmer Jensen came up with a real winner, even after 50 years, which is why a fair number are still being built today. But whatever you build,

Happy Building

 



Jon McDonald
Homebuilder or Craftsman
25
Posts
12
#10 Posted: 10/28/2009 03:07:26

Great writeup on the Kingfisher and the VJ22.

One downer I have heard about the VJ22 is that with just a C90 or O-200 It doesn't perform well at gross (1500lbs).  Have you heard the same or something different?



Jon McDonald Building Sonex #1287
Martin Stentzel
8
Posts
5
#11 Posted: 11/8/2009 01:20:35

Hi Jon,

Not having any personal experience I hope folks who know firsthand will post their answers, but for now, from reading on the Volmer forum the feel I get is that an 0-200 will give you just basic performance. You can get by okay if you built the plane light and your water ops are lower altitude. My very rough guess is maybe close to half have 0-200s  and half have 0-290s, with some 0-235s, Franklins and auto conversions.

I read of one guy with an 0-320 but that seemed to be considered overkill. One guy with a newly-built plane and an 0-200 said he couldn't quite get on the step at 1500 lbs, but the replies thought there must be something wrong and it did come out he didn't have any spray rails yet. Afterall, Volmer Jensen flew Chubasco all over, with his friends from Canada to Baja and back East with a C-85 pusher/wood prop installation. There are plenty of owners with 0-200s who seem okay with their power, but I suppose it might be fair to call it's performance marginal in that conditions need to be reasonably favorable (wt & alt). But then people say a Cessna 150 is marginal yet I used to take one (with friend and camp gear) in the ID backcountry. I suppose most folks would say 125-135 hp is pretty ideal, and neccessary if your gross is higher (like 1800lbs).

Just my feel of it Jon; I too would like to hear firsthand reports.