Shoulder wing unpopularity

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

Victor Bravo

Well-Known Member
Joined
Jul 30, 2014
Messages
7,255
Location
KWHP, Los Angeles CA, USA
I will gladly tell you about my experience with Yamaha motorcycle engines... I have none whatsoever.

Now if you would be kind enough to tell me how many hours have been flown on the RX-1 propeller redrive and control system, I would like to compare that number of successful RX-1 redrive and ECU hours to the number of successful hours flown using the 912 Rotax propeller reduction, and ECU control system :)
 

deskpilot

Well-Known Member
Joined
Jun 30, 2009
Messages
1,123
Location
Morphett Vale, South Australia. Just south of Adel
The Suzuki G10 with a redrive (or the similar Aeromomentum AM10) would be a good choice for a Cygnet as well.

BREAK

For no particular reason, here's a neat video of my favorite shoulder-wing aircraft. You'll want to fast forward through parts of it if you don't speak Czech (I don't either) but the footage at the beginning and end is worth it.

I see this as a high wing, not a shoulder wing
 

Pilot-34

Well-Known Member
Joined
Apr 7, 2020
Messages
354
To me, the shoulder-wing is nice for visibility, but one also has to weigh safety, specifically egress when inverted. The typical low-wing airplane has a real problem there, and an airplane like the Cygnet doesn't improve on it at all. A high-wing airplane is much more likely to let its victims out quickly.

The Lake amphibs are shoulder-wing affairs, but CG movement is large because everybody in it is ahead of the CL. When everone is out you can lift the nosewheel off the ground with no effort at all. The tail of an LA-4 will almost stay on the ground if you put it there. That presents a problem when tied down in the wind, so the control lock holds the elevator down. With the wind on the tail, though...
The lake is probably the most manufactured model of a shoulder wing aircraft ,any idea why lake (Thurston )chose to put it there?
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
5,279
The lake is probably the most manufactured model of a shoulder wing aircraft ,any idea why lake (Thurston )chose to put it there?
If you look closely at it, you see that it's actually a high wing airplane. The fuselage is a tiny bit shallower than a Cessna 182, for instance, and the wing spars are at the top of the longerons. Everything above that is just a shell. The engine mount pylon spars extend through the shell to the wing spars, as do the pylon braces. The airplane looks like a shoulder wing because of the engine far above it and the keel a few inches off the pavement.

If we lowered a 182 until its belly was six inches off the ground and put the engine up top, above the wing, it too would look like a shoulder-wing airplane. We'd also have to raise the floor to allow for the V-hull's depth, which raises the occupants so that their eyeballs are at wing level. And we'd have to raise the ceiling for that.
 

Pilot-34

Well-Known Member
Joined
Apr 7, 2020
Messages
354
If you look closely at it, you see that it's actually a high wing airplane. The fuselage is a tiny bit shallower than a Cessna 182, for instance, and the wing spars are at the top of the longerons. Everything above that is just a shell. The engine mount pylon spars extend through the shell to the wing spars, as do the pylon braces. The airplane looks like a shoulder wing because of the engine far above it and the keel a few inches off the pavement.

If we lowered a 182 until its belly was six inches off the ground and put the engine up top, above the wing, it too would look like a shoulder-wing airplane. We'd also have to raise the floor to allow for the V-hull's depth, which raises the occupants so that their eyeballs are at wing level. And we'd have to raise the ceiling for that.
1587984211630.jpeg
 

Pilot-34

Well-Known Member
Joined
Apr 7, 2020
Messages
354
Lol I expected someone might argue the lake was a mid wing.
But in the end we are talking about a few inches so how much can it really matter ?
In either case it does illustrate that a spar running through the shoulder area of the occupants puts most of the seat loads ahead of the center of lift.

does anyone have a LA-4-200
Weight and balance worksheet ?
I was curious enough to look one up in the owner’s manual but apparently they are supplied separately.
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
12,823
Location
Memphis, TN
A lake is probably one of the only planes that needs the compromise of a shoulder wing. Has to be tall enough on the ground with gear down, and not drag in water. Gear is long at shoulder height, don’t need any longer. Wing need to be low enough so tip floats are stretched excessively to the water.
 

BJC

Well-Known Member
HBA Supporter
Joined
Oct 7, 2013
Messages
11,072
Location
97FL, Florida, USA
The Lake is described as a “shoulder wing” in the POH, and the wing, does, indeed, align with a typical sized pilot’s shoulder.

But you can buy the TC and call it anything that you want, just don’t change the TC. See Lake Amphibian type certificate for sale

The shoulder wing positions the sponson such that the sponson is subject to dragging on the runway when the wing is lowered to counteract a crosswind. An acquaintance who has one will not land on ground it the crosswind component exceeds 12 knots.


BJC
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
5,279
Lol I expected someone might argue the lake was a mid wing.
But in the end we are talking about a few inches so how much can it really matter ?
In either case it does illustrate that a spar running through the shoulder area of the occupants puts most of the seat loads ahead of the center of lift.

does anyone have a LA-4-200
Weight and balance worksheet ?
I was curious enough to look one up in the owner’s manual but apparently they are supplied separately.
With everyone out of the airplane you can easily pick the nose up with one hand. Makes it easy to move around on the ground, backing it into its parking spot. The castering nosewheel doesn't like rolling straight back.
 
Top