How to find the real gross weight a plane can carry?

Talk about airplanes! At last count, there are 39 (and growing) FAA certificated S-LSA (special light sport aircraft). These are factory-built ready to fly airplanes. If you can't afford a factory-built LSA, consider buying an E-LSA kit (experimental LSA - up to 99% complete).

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WDD
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Re: How to find the real gross weight a plane can carry?

Postby WDD » Tue Feb 20, 2018 4:50 pm

FastEddieB wrote:
And why even waste time on pointless hypotheticals?


1) It's winter, I'm bored to death.
2) Bad weather has cancelled out my last 3 scheduled flight lessons.
3) Looks like this weekend will be a scrub as well.
4) Might as well take advantage of this "dead time" to learn as much as I can.
5) Did I mention it's winter, no flying, bored to death?

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drseti
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Re: How to find the real gross weight a plane can carry?

Postby drseti » Tue Feb 20, 2018 5:01 pm

FastEddieB wrote:why even waste time on pointless hypotheticals?


And furthermore, Eddie, why do there have to be rhetorical questions?
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
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Jim Hardin
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Re: How to find the real gross weight a plane can carry?

Postby Jim Hardin » Tue Feb 20, 2018 7:00 pm

A couple more thoughts...

If an aircraft 'can' carry more than it is certified for, it in no way implies it is a "safer airplane".

VA, maneuvering speed, is set based on the aircraft at maximum gross weight and is the speed it will Stall at before the G limits are exceeded. If you are less than 1320 lbs (for LSA), you will exceed your structural limits before you reach VA. In that case it is moot if the spar can carry 10,000 pounds. When it comes to VA, heaver is better.

What are the G limits (load factor) of an LSA? Well they are aircraft specific. Most will be +4g's and -2g's, flaps UP!

The Sting drops to +2g's -2g's with flaps down.

Gobosh is only +4g's -1g flaps up and drops to +2g's 0g with flaps down.

So what happens when those limits are exceeded? It does not necessarily mean the wings fall off. Recall the V tail Bonanza VNE fail mode. The stabilizers would twist throwing such a tremendous negative g load that the engine mount would break off upward and that big Continental would go through the windshield. Outer wing panels would come off somewhere along this scenario too.

So what does break? The weakest part or parts. Could be the flashing beacon, taking a piece of the rudder with it. Could be your seat, glare shield, fuel pump, trim actuator, etc.

So don't think that a greater gross weight potential implies a safer airplane. Too many other factors are in there.

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Re: How to find the real gross weight a plane can carry?

Postby Mark Gregor » Tue Feb 20, 2018 9:06 pm

Some LSAs are certified to higher weights in other countries and are artificially held to the lower LSA weights here in the USA. You would likely need to ask each manufacturer if they have a higher certified weights for their aircraft.

This should be very important to potential purchasers because in most cases (although not always as Jim pointed out above) this indicates a safer, stronger and more durable aircraft.
For example, of the two aircraft the the OP mentioned one has already had three airframe SBs that came about because of failures in the field. That should get your attention.
The other aircraft mentioned has had regular landing gear failures that has led to landing incidents and accidents. This type of accident doesn’t usually cause injury although the pilots ends up with a broken plane, damage history, an accident on their FAA pilot record and likely insurance issues.

Most times the aircraft with the highest useful loads are at the price of safety and durability.

The trend to heavier LSAs is mainly due the reasons mentioned above.

You might want to consider this. Currently the best selling LSA in the USA is also the heaviest. It is sold at a higher gross weight outside of LSA. It enjoys a very good safety and durability record. Many of you know I work for Tecnam. I wish we had the best selling aircraft in the usa mentioned above but we do not. At least not yet.

I am not advocating flying overweight so please don’t come back with that. It’s just not as simple as we might like.


Mark

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Re: How to find the real gross weight a plane can carry?

Postby Mark Gregor » Tue Feb 20, 2018 9:15 pm

Obviously there is a price factor also. Not all of us can just just go buy whatever airplane we want. I sell Tecnam’s and yes I know they are expensive.

I understand and respect that cost dictates much of what can or can not do regardless of our wants.

Mark

Warmi
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Re: How to find the real gross weight a plane can carry?

Postby Warmi » Tue Feb 20, 2018 9:29 pm

Mark, the string of landing failures you mentioned , is that for the sling 2?

Just curious ...
Flying Sting S4 ( N184WA ) out of Illinois

Mark Gregor
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Re: How to find the real gross weight a plane can carry?

Postby Mark Gregor » Tue Feb 20, 2018 9:53 pm

Warmi,

No it is not the Sling. I was thinking of another aircraft that was not mentioned. Sorry, my mistake.

Mark

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Jim Hardin
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Re: How to find the real gross weight a plane can carry?

Postby Jim Hardin » Wed Feb 21, 2018 6:30 am

I don't see why we are so careful to keep identity a secret... If an aircraft has a record/history, that isn't a secret but not everyone has the knowledge of where to research something.

But you have to keep in mind that a things like a history landing incidents are only cause for a question. Our Gobosh had a rash of flat spots on the main tires. People were landing while pressing on the toe brakes. This was a combination of new pilots and a design that made it easy to do. Other aircraft that were used in training or by low time pilots suffered gear issues.

So a 'history' raises a question as to cause but is not, by itself, an indictment of a make/model :wink:

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Re: How to find the real gross weight a plane can carry?

Postby Merlinspop » Wed Feb 21, 2018 7:36 am

Jim Hardin wrote:I don't see why we are so careful to keep identity a secret... If an aircraft has a record/history, that isn't a secret but not everyone has the knowledge of where to research something.
So a 'history' raises a question as to cause but is not, by itself, an indictment of a make/model :wink:

I think Mark just wants to avoid sounding like he's trashing a competitor's product. I can respect that.
- Bruce

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Jim Hardin
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Re: How to find the real gross weight a plane can carry?

Postby Jim Hardin » Wed Feb 21, 2018 10:16 am

Merlinspop wrote:I think Mark just wants to avoid sounding like he's trashing a competitor's product. I can respect that.


Oh, I agree. I can be very vague if I want and unless it involves a well known defect or something unique to a perticular aircraft, I will likely avoid mentioning make and model.

IE: Does anyone know how to fill a Remox GX without overflow and getting gas all over your feet? vs try to stand upwind when fueling to prevent overflow spray getting all over you.

The first is model specific but the second is pretty general and actually aimed at my cub cadet lawn mower :D

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Re: How to find the real gross weight a plane can carry?

Postby drseti » Wed Feb 21, 2018 12:00 pm

Jim Hardin wrote: the second is pretty general and actually aimed at my cub cadet lawn mower :D


I'm so glad you clarified that, Jim. When I first moved to the Lock Haven area 3 decades back, I was surprised to see dozens of ads in the local paper for Cub Cadets a unbelievably low prices. Now, I had been expecting to see numerous Cubs available hereabouts, and was quite familiar with the various J models, the Cruiser, and the SuperCub, but I had never heard of a model called the Cadet. If only someone had included the words "lawn mower," that would have saved me a lot of confusion.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US

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Re: How to find the real gross weight a plane can carry?

Postby 3Dreaming » Wed Feb 21, 2018 12:29 pm

drseti wrote:
Jim Hardin wrote: the second is pretty general and actually aimed at my cub cadet lawn mower :D


I'm so glad you clarified that, Jim. When I first moved to the Lock Haven area 3 decades back, I was surprised to see dozens of ads in the local paper for Cub Cadets a unbelievably low prices. Now, I had been expecting to see numerous Cubs available hereabouts, and was quite familiar with the various J models, the Cruiser, and the SuperCub, but I had never heard of a model called the Cadet. If only someone had included the words "lawn mower," that would have saved me a lot of confusion.


I have a friend who would be quick to point out that a Cub Cadet is not a lawn mower, it is a lawn tractor. At least that's the way it used to be before they started selling junk based on name recognition.

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Re: How to find the real gross weight a plane can carry?

Postby MrMorden » Wed Feb 21, 2018 1:35 pm

WDD wrote:
Sling 2 Pilot wrote:. The version they sell abroad is no different structurally than the version sold here. However the certification is. What it says is what you get...1320 is 1320. Want or need more, go experimental or move across the pond....


Or..... add floats! You can take the same plane and go up a hundred pounds or so by virtue of it being able to operate on water.


Most floats weigh over 110lb for a pair, so usually you lose carrying capacity.
Andy Walker
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Re: How to find the real gross weight a plane can carry?

Postby drseti » Wed Feb 21, 2018 1:54 pm

The J-3 Cub in which I trained at Jack Brown's started out at 1220 gross. On floats, that was raised by somewhat less than the weight of the floats, so true, we lost payload.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof H Paul Shuch
PhD CFII DPE LSRM-A/GL/WS/PPC iRMT
AvSport LLC, KLHV
fly@AvSport.org
AvSport.org
facebook.com/SportFlying
SportPilotExaminer.US

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Re: How to find the real gross weight a plane can carry?

Postby WDD » Wed Feb 21, 2018 5:10 pm

3Dreaming wrote:I have a friend who would be quick to point out that a Cub Cadet is not a lawn mower, it is a lawn tractor. At least that's the way it used to be before they started selling junk based on name recognition.


Let's see..... Lawn Tractor = Ride able lawn cutting machine that has the engine front of rider


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