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

Postby TimTaylor » Tue Feb 20, 2018 12:20 am

I'm not arguing with anyone, just making a point and inserting a little levity. I'm only one of about five people who made the same point in this thread. Regardless of your original intent, you brought up the topic. When you ask a question, you don't get to dictate the answer, even if the answer is not really in response to your question. These threads have a life of their own.
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Re: How to find the real gross weight a plane can carry?

Postby drseti » Tue Feb 20, 2018 9:02 am

OK, gang, we've all had our say, and beaten this issue to death. I suggest we move on now .
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Re: How to find the real gross weight a plane can carry?

Postby 3Dreaming » Tue Feb 20, 2018 10:06 am

TimTaylor wrote:I thought this was Sport Pilot Talk.


It was nice of you to use your better judgement and remove the previous post that was in this space. Yes this is Sport Pilot Talk, if you look to the top of the page it says it is for, "The discussion forum for Sport Pilots and Light Sport Aircraft". Were you not talking about Light Sport Aircraft, because I was. You were confusing pilot limitations with aircraft limitations. The 1320 pound gross weight is a aircraft limitation. Flying IFR can be a aircraft limitation, but it is definitely a sport pilot limitation. Flying at night or above 10,000 feet is a pilot limitation, not an airplane limitation as you implied.

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

Postby TimTaylor » Tue Feb 20, 2018 10:11 am

I removed no post except when I told you to ****. I am confusing nothing. I was making an example of ignoring the rules. Please just speak for yourself and I will speak for myself. Let's let Paul do the moderating. Thanks.
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Re: How to find the real gross weight a plane can carry?

Postby 3Dreaming » Tue Feb 20, 2018 10:32 am

TimTaylor wrote:I removed no post except when I told you to ****. I am confusing nothing. I was making an example of ignoring the rules. Please just speak for yourself and I will speak for myself. Let's let Paul do the moderating. Thanks.


Removed or edited, what ever you want to call it. I saw what was there, and you know what was there.

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

Postby Wm.Ince » Tue Feb 20, 2018 10:44 am

3Dreaming wrote:Removed or edited, what ever you want to call it. I saw what was there, and you know what was there.

Darn! . . . Looks like a fly landed in the ointment again. :D
Agree with Paul . . . time to move along.
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Re: How to find the real gross weight a plane can carry?

Postby FastEddieB » Tue Feb 20, 2018 10:45 am

drseti wrote:OK, gang, we've all had our say, and beaten this issue to death. I suggest we move on now .


I’ll respect that.

But I did have a couple of points rattling around in my head related to this topic.

Look for a new thread soon, working title: “Pick and Choose?”
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Re: How to find the real gross weight a plane can carry?

Postby TimTaylor » Tue Feb 20, 2018 11:02 am

3Dreaming wrote:
TimTaylor wrote:I removed no post except when I told you to ****. I am confusing nothing. I was making an example of ignoring the rules. Please just speak for yourself and I will speak for myself. Let's let Paul do the moderating. Thanks.


Removed or edited, what ever you want to call it. I saw what was there, and you know what was there.

Remind me then. Maybe I forgot. Seem like maybe I posted something and immediately deleted it. If so, I’m sure it was deserved.
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Re: How to find the real gross weight a plane can carry?

Postby MrMorden » Tue Feb 20, 2018 11:14 am

I think the “reserve performance” argument is a bit misleading. Almost all popular LSA have engines in the 80-120hp range. Thinking an airplane that can fly at 1600lb must perform better than one only “good” to 1320lb ignores the primary performance attributes: power to weight, empty weight, and control harmony.

If two airplanes both have 100hp engines and similar empty weights, one is not going to perform better than the other just because it’s allowed to operate at 1320lb. To the contrary, at 1600lb that airplane will probably be a dog, with performance like a Cessna 152 on a hot day. At 1320lb the two airplanes will perform similarly, assuming similar layout, drag, aerodynamics, etc.

Extra structural strength can help in some circumstances, but only those where the design limits of the airplane are exceeded by doing something you shouldn’t...over-g while maneuvering, flying into severe turbulence/storms, or pancaking in on the gear, for example.
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Re: How to find the real gross weight a plane can carry?

Postby Merlinspop » Tue Feb 20, 2018 11:58 am

So... I've been watching this thread and the very heated reactions to the question. I know everyone here (okay, maybe not everyone) is spring loaded to pounce on everyone who asks a question similar to "I know that the legal LSA limit is 1320, but I want to put 1500# in my SuperBugSmasher LSA; can it take it? It does in Europe??!!". This scenario has played out time and time again, and I agree with the message (the limit is the limit...period), but often not the hostility that accompanies it.

BUT... When I read the OP's post... I didn't take his question to be another way to ask that question. what I *thought* he was asking, and I wish we would discuss (with a degree of civility, please), is "How do I find out the ultimate demonstrated structural strength of a given LSA model?" I did a search just now and couldn't find (it was a brief search) the positive and negative load factors that SLSAs must meet. Does anyone have that handy?

I also seem to remember that, per the standards, the manufacturer does not need to complete physical testing to verify that their design meets this standard, but rather a calculated load limit of the design will suffice. This would give me a bit of pause, frankly. I would be much happier to see results of actual testing to destruction of a test article. This is one reason why I like the Carbon Cub so much (not that I can afford one). They have tested the airplane to determine it's real, ultimate strength, and based on that, have set a much higher weight for their E-AB version. This would make me much much more comfortable knowing that a Carbon Cub could survive a wake encounter or some other event that may put excessive load on the airframe. I would have less confidence in other aircraft that have never been tested to destruction. Nowhere in this have I stated or implied any intention whatsoever to exceed the 1320 pound LSA limit. Only wanting to know how strong is an airframe at the 1320 pound weight before parts deform and then when they fail.

Now, this is probably a moot question, as we aren't seeing SLSA's folding up wings and tail feathers left and right. But still, if I'm considering buying an airplane and putting one of my sons in it, I'd kinda like to know just how robust this airplane is. THAT, I thought, was the gist of the OP.
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Re: How to find the real gross weight a plane can carry?

Postby TimTaylor » Tue Feb 20, 2018 12:14 pm

drseti wrote:OK, gang, we've all had our say, and beaten this issue to death. I suggest we move on now .

Thanks Paul. I am moving on and will not respond further.
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Re: How to find the real gross weight a plane can carry?

Postby WDD » Tue Feb 20, 2018 3:05 pm

MrMorden wrote:I think the “reserve performance” argument is a bit misleading. Almost all popular LSA have engines in the 80-120hp range. Thinking an airplane that can fly at 1600lb must perform better than one only “good” to 1320lb ignores the primary performance attributes: power to weight, empty weight, and control harmony.

If two airplanes both have 100hp engines and similar empty weights, one is not going to perform better than the other just because it’s allowed to operate at 1320lb. To the contrary, at 1600lb that airplane will probably be a dog, with performance like a Cessna 152 on a hot day. At 1320lb the two airplanes will perform similarly, assuming similar layout, drag, aerodynamics, etc.

Extra structural strength can help in some circumstances, but only those where the design limits of the airplane are exceeded by doing something you shouldn’t...over-g while maneuvering, flying into severe turbulence/storms, or pancaking in on the gear, for example.


Interesting - a different way for me to think about "performance". Thanks -

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

Postby WDD » Tue Feb 20, 2018 3:15 pm

Merlinspop wrote: Only wanting to know how strong is an airframe at the 1320 pound weight before parts deform and then when they fail.
Now, this is probably a moot question, as we aren't seeing SLSA's folding up wings and tail feathers left and right. But still, if I'm considering buying an airplane and putting one of my sons in it, I'd kinda like to know just how robust this airplane is. THAT, I thought, was the gist of the OP.


Yes -

Folks, didn't mean to trip wire a land mine here. What I've learned from just the nature of the responses is that there seems to be some past history of Sport Pilots who wanted to go beyond the 1320 lbs. Maybe I'm too simplistic, but I have visions of the CG being off, the plane not gaining altitude as it should, not getting out of a stall or spin, and generally not being as controllable as it should. Or always wondering if it will get that way if I hit turbulence.

So, thanks for the spirited discussion. Carry on.........

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

Postby Sling 2 Pilot » Tue Feb 20, 2018 3:47 pm

In the end, just know...there are aircraft out there that were originally designed, built and certified with a higher gross weight and that the manufacturer decided to certify as an S-LSA to market here in the USA. 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....

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

Postby WDD » Tue Feb 20, 2018 4:26 pm

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.


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