Jack Pelton comments on LSA weight restrictions

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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MrMorden
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Re: Jack Pelton comments on LSA weight restrictions

Postby MrMorden » Tue Jul 24, 2018 10:01 am

FastEddieB wrote:I wonder if the owner of an ELSA could raise the maximum gross above 1,320 lbs, based upon his or her estimation of the safety of doing so?

I mean, let’s say I knew for a fact that my Sky Arrow was identical to models rated elsewhere to 1,450 lbs (I’m not). But I think others may be in that situation where the 1,320 lbs is a clearly arbitrary limit.


I think you can absolutely do this, provided the aircraft is tested at the new weight and found to remain within LSA limits (clean stall speed being the biggest concern).

The best case scenario here would be an increase in weight to ~1500-1600lb AND an increase in clean stall from 45KCAS to 50-60KCAS. Probably too much to wish for all at once, but, here's hoping!

Cue Paul (rightly) reminding us about increased risk from rising stall speed and energy going up exponentially in 5...4...3...2...1... :lol: :lol: :lol:
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2007 Flight Design CTSW E-LSA

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Re: Jack Pelton comments on LSA weight restrictions

Postby MrMorden » Tue Jul 24, 2018 10:30 am

ShawnM wrote:Why is everyone hell-bent on changing this rule? :o


Because frankly...it kind of sucks.

Sure, it's better than the original ~1230lb proposed LSA limit, but 1320lb is still a very tough limit for an airplane to hit and still have utility. And while LSA are primarily for pleasure and not "workhorse" airplanes, they still have a mission to fulfill, and that's hard to do when you have a two seat airplane that cannot legally take two normal adults and full fuel, not to mention some cargo like camping gear or weekend bags. There are a great number of LSA whose useful load is barely 500lb, and many in the 480-490lb range. And the fact is that in most cases this is not a design limit imposed by engineering and physics, but a bureaucratic limit imposed by the FAA.

The original idea is that the lower weight and stall speeds increase safety. That has some merit as far as it goes as far as impact energy is concerned. However, the lower weight and low wing loadings have other less desirable effects as well: more susceptibility to wind effects, twitchier handling characteristics, and less weight available for impact-absorbing structure and safety systems.

The Sport Pilot rule was feared to cause many pilots to fall from the sky as they slumped over the controls from heart attacks, strokes, and all the other medical issues the class 3 medical was designed to prevent. The reality has been *much* different. There have been a few head-scratching accidents, but not one confirmed documented case of a pilot flying under sport pilot rule being incapacitated at the controls and leading to a crash. At the very least, there are no more SP deaths at the controls than there are ATP deaths at the controls, which happens about once a year. It turns out pilots actually value their lives and generally don't fly when they know they are not fit to do so.

IMO, the easiest, simplest, and best way to solve this whole issue is to do away with the Sport Pilot / LSA rules, and simultaneously remove the class three medical requirements, and instead have BasicMed-style medical training requirement. There would be some minor exceptions needed to be made for existing SPs and LSAs, but the entire landscape of aviation would be flattened and simplified, and only non-commercial pilots needing to fly internationally would need a medical.
Andy Walker
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Re: Jack Pelton comments on LSA weight restrictions

Postby MrMorden » Tue Jul 24, 2018 10:33 am

drseti wrote:
ShawnM wrote:Why is everyone hell-bent on changing this rule? :o


Americans are greedy, Shawn. They want more of everything. A 6000 pound, retractible, injected, turbocharged, constant speed prop, six-place pressurized twin LSA for $100k would sell really well, I'm sure!


A trait of humans, not Americans. Nobody wakes up in the morning in any nation, and says to himself: "I really hope my life doesn't improve today. maybe it will even get worse if I'm lucky!" :roll:
Andy Walker
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Re: Jack Pelton comments on LSA weight restrictions

Postby drseti » Tue Jul 24, 2018 10:35 am

MrMorden wrote:Cue Paul (rightly) reminding us about increased risk from rising stall speed and energy going up exponentially in 5...4...3...2...1... :lol: :lol: :lol:


OK, Andy, I'll bite.

Don't forget, folks, that these changes will increase kinetic energy, and survival in the event of an accident is inversely proportional to KE. This is discussed in other threads, but since Andy asked:

KE = 1/2 m v^2

So, KE goes up with mass. That's Strike One.
And, KE goes up with stall speed. That's Strike Two.
But, KE goes up with speed squared. And, stall speed increases with mass anyway, so... Strike Three!

Bottom line: heavier is not without its own risks.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
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Re: Jack Pelton comments on LSA weight restrictions

Postby Wm.Ince » Tue Jul 24, 2018 11:39 am

Warmi wrote:Well, one thing it is going to do is to kill the aftermarket for LSAs that can’t be STCed .... :D

That's a very broad stroke of your brush.
I don't think it will make a bit of difference with my CTSW. It has good performance and capability (payload/range) as is.
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MrMorden
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Re: Jack Pelton comments on LSA weight restrictions

Postby MrMorden » Tue Jul 24, 2018 11:55 am

drseti wrote:So, KE goes up with mass. That's Strike One.
And, KE goes up with stall speed. That's Strike Two.
But, KE goes up with speed squared. And, stall speed increases with mass anyway, so... Strike Three!


You don't have to bite, I wasn't goading, just pointing out you have (again rightly) pointed this out whenever weight & stall speed come up.

I agree on strike one and three.

How does Kinetic energy increase with stall speed? Kinetic energy is a function of mass and velocity, and nothing to do with aerodynamics. Stall is an aerodynamic effect. Unless you meant that the higher landing speed means higher energy, which is true...but i think that is captured by strike 3.

QED in any case.
Andy Walker
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2007 Flight Design CTSW E-LSA

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Re: Jack Pelton comments on LSA weight restrictions

Postby Warmi » Tue Jul 24, 2018 12:02 pm

Wm.Ince wrote:
Warmi wrote:Well, one thing it is going to do is to kill the aftermarket for LSAs that can’t be STCed .... :D

That's a very broad stroke of your brush.
I don't think it will make a bit of difference with my CTSW. It has good performance and capability (payload/range) as is.


The point here is that if you want to sell your LSA ( for whatever reason ) and there are 10 other LSAs on the market with gross set at , say , 1600 LBS ( some of them even, say, CTLS planes built after the rule was passed ) and your is stuck at 1320 ... well, that's gonna make it that much harder to sell your LSA - the only way you will be able to compete is by lowering the asking price.
Flying Sting S4 ( N184WA ) out of Illinois

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Re: Jack Pelton comments on LSA weight restrictions

Postby c162pilot » Tue Jul 24, 2018 12:18 pm

I am going to go out on a limb here and postulate that the revised S-LSA standard may look similar to the EASA CS-VLA standard, that is 750 Kilogram (1,563 lbs) maximum weight, single spark or compression ignition engine, 2 seats, Day VFR and Stall speed less than 45 knots. There is no mention in CS-VLA specs of maximum speed, constant speed propeller or fixed gear. It appears there may be a process called SC (Special Condition) to allow for Night VFR, IFR operations and a 3rd seat.

I assume that to increase weight and keep the stall speed under 45 Kts if the current stall speed is already at 45 kts, would require a re-design of the wing.

Links to information on CS-VLA:
https://en.wikipedia.org/wiki/EASA_CS-VLA
https://www.easa.europa.eu/sites/default/files/dfu/decision_ED_2003_18_RM.pdf page 1-A-1

Interesting there is a Sling 2 variant called the Sonaca 200 built in Belgium that is CS-VLA certified at 750 Kgs vs 700 Kgs in South Africa.
http://www.sonaca-aircraft.com/products/sonaca-200

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Re: Jack Pelton comments on LSA weight restrictions

Postby drseti » Tue Jul 24, 2018 12:27 pm

MrMorden wrote:You don't have to bite, I wasn't goading


I wasn't biting, Andy, and didn't think you were goading. :)


How does Kinetic energy increase with stall speed?


It doesn't, directly. But since the great majority of LSA accidents occur during takeoff and landing, at or close to stall speed, I think calculating KE under those conditions is relevant.

i think that is captured by strike 3.


Sort of. But I make the distinction deliberately, to underscore the multiplicative nature of the parameters, leading to a logarithmic relationship. Consider in the KE equation that (m) is Strike One, (v) is Strike Two, and at (^2), You're Out!
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
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Re: Jack Pelton comments on LSA weight restrictions

Postby foresterpoole » Tue Jul 24, 2018 12:49 pm

The point here is that if you want to sell your LSA ( for whatever reason ) and there are 10 other LSAs on the market with gross set at , say , 1600 LBS ( some of them even, say, CTLS planes built after the rule was passed ) and your is stuck at 1320 ... well, that's gonna make it that much harder to sell your LSA - the only way you will be able to compete is by lowering the asking price


For those of use looking for a newer air frame who generally fly alone or with minimal baggage/passenger weight, lower prices might be a desirable outcome! :lol:
Ed

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Re: Jack Pelton comments on LSA weight restrictions

Postby ShawnM » Tue Jul 24, 2018 1:05 pm

Ok, everyone stop what you're doing......look down......can you see your belt buckle or toes?

If not, I'd start there and stop blaming the aircraft. :mrgreen:

Paul is right, if you increase the weight limit you have many more issues to think and worry about. Heavier is not without its own risks.

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Re: Jack Pelton comments on LSA weight restrictions

Postby Nomore767 » Tue Jul 24, 2018 2:01 pm

Wm.Ince wrote:I don't think it will make a bit of difference with my CTSW. It has good performance and capability (payload/range) as is.


Totally agree.
In all my years of flying , from Cherokees to transports, there are few airplanes that offer what most LSAs do for MY mission....retired pilot, fun flying, cost effective, great performance, ease of ownership, room for two but mostly solo, full auto gas fuel giving 3.5 hour range at almost 120kts, high tech glass cockpit, almost no oil consumption, $375 annual, still some room for baggage with full fuel and two folks, all for $14 hr in gas.
I chose the RV-12 SLSA and all of the above applies. I’d bet CTSW and similar LSAs achieve the same or similar.
If I trade up to the new RV-12iS SLSA, not available yet, it offers some improvements but with a probable $35k increase over what I paid for my RV-12 bought new. When/if manufacturers start to design/produce higher weight “light sport” airplanes I’m sure the price will be north of $250k, exactly the opposite of what folks said they wanted before the advent of light sport flying, where simplicity and economy were the watchwords. It isn’t tempting me.

Sure, a revised rule would eliminate owners “forced” to fly overweight in order to gain utility, but it would have to spell out how each model or even each individual airplane may need to be recertifide to fly at the new weight, with new operating speeds and limits. Who foots the bill for this? How long does it take? Will Vashon, for example, pay more $$$ in order to offer its Ranger at 1600-1700lbs?

It would be great to include airplanes such as Cessna 150s as part of light sport. That said, I can’t see anything that would change my current status flying light sport in my RV-12.
Unless I won the lottery!

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Re: Jack Pelton comments on LSA weight restrictions

Postby Warmi » Tue Jul 24, 2018 2:23 pm

I think the new rule could simply restate what is already the standard in the LSA world - the manufacturer gets to decide what can be installed on the plane and also what is the allowed gross lbs for that particular model ...as long as it doesn’t take it out of LSA category ...
Flying Sting S4 ( N184WA ) out of Illinois

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Re: Jack Pelton comments on LSA weight restrictions

Postby ShawnM » Tue Jul 24, 2018 3:13 pm

Wm.Ince wrote:.....I don't think it will make a bit of difference with my CTSW. It has good performance and capability (payload/range) as is.


Same here with my legacy SportCruiser. I have a 524 pound useful load and her performance and capability are both quite good. :mrgreen:

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Re: Jack Pelton comments on LSA weight restrictions

Postby HornedFrogGrant » Tue Jul 24, 2018 9:41 pm

So if gross weight increases, what's to stop the typical empty weight of LSAs from creeping upward, due to the perception of more "wiggle room" for optional gadgets and gizmos?

I'd be happy to see the gross weight increased, but I fear that manufacturers would interpret it as a green-light to build heavier empty LSAs. Which would have the practical effect of making the gross weight increase all for naught.

Just my $0.02.


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