Sportcruiser Weight Limits

[Wjherman]

As a new Sportcruiser owner, I have been told (off the record) that the Sportcruiser was actually built to handle much higher maximum weight limits than allowed by the US Light Sport standards (1320 lbs.) I'm certainly not interested in testing the weight limits, just curious to hear if this information is based on any factual information.

 

Thanks,

John

[DavePilot]

the SportCruiser would NOT be an effective design

if it had

zero margin above

the Light Sport Aircraft 1320 lb limit....

Having said that, it is of course illegal in the FAA regulated USA
to fly a Light Sport Aircraft (non amphibian) loaded with fuel, baggage and occupants
With takeoff weight above the LSA 1320 lb legal limit.

And I doubt that anyone "in the know" would reveal the actual design limits....

And of course exceeding the 1320 lb limit would put the Pilot and passenger in uncharted waters, effectively becoming a beyond the envelope Flight Test with the PIC acting as a "Test Pilot" exposed along with the passenger to possibly unsafe and unknown conditions for the survival of the structure of the aircraft.

Classic effects of an overloaded aircraft:

Higher takeoff speed and Longer takeoff run
Reduced rate and angle of climb
Shorter range and Reduced cruising speed
Reduced maneuverability and control effectiveness
Higher stalling speed and potential inability to recover from a stall
Higher approach and landing speed and Longer landing roll
Excessive weight on the nose wheel possibly leading to gear failure and prop strike
Potentially hidden structural damage that may weaken key elements of the aircraft

Control effectiveness, flutter, stall recovery, stability, turbulence survival,
and reduced margin on ultimate structure limits and more might be affected by an overloaded LSA.

A great question though. Wonder what actual design limits have been tested to by CSA
either on the ground with g load limit tests or airborne in CSA flight test at beyond 1320 lbs ?

From a Mechanical Engineering standpoint, it is easier to "design in" more safety margin on
a much heavier aircraft like a Cessna 182 heavy load hauler, than it is to design in additional safety margin on an 800 lb Light Sport Aircraft. Heavier stronger structures just won't fit as easy in an 800 lb total weight budget, for example. On an unrelated note, the BRS-6 1350 soft pack Ballistic whole airframe parachutes that some SportCruisers carry is only rated to 1350 lbs (612 kg). Very low margin above the
1320 lb LSA legal limit. I am not implying that 1350 lbs would be OK for an LSA. It is not. Just showing
the limited margin of the parachute and rocket motor, that together also consume some (29 lbs) of that limited 800 lb example aircraft empty weight budget.

A challenging problem.

D

[ShawnM]

I agree with Dave on his points and I'm willing to bet the 1320 limit is a conservative number for the all metal SportCruiser. Our same plane is made for the UK market and their MTOW is 600 kg or 1322 pounds.

 

Is there a "fudge factor" built in, of course, will I test it, oh no! 

[ronin5573]

The sportcruiser wasn't designed to be a light sport.  It was converted to that standard. I Wouldn't admit to flying it overweight but I herd some really reliable info that at 1600 lbs it flys fine.  Of course maneuver speed increases to maybe 90 ish.  My particular aircraft stalls dirty at 34 knots.  that stall speed never seems to change light or near max gross weight. Not to sure about power on stalls as I don't do them to much.  For me 100% power on stalls the pitch up angle is pretty extreme and I worry about the carbs not picking up fuel, but maybe I'm nuts as I've never had a problem.  Seems you eventually learn your particular aircraft.  Book says 5500 rpm is max continus power.  Mine seems happy at 5200 in cruise burning about 5.4 gph.  more rpm doesn't increase speed that much but burns 6.5 gph at 5500 rpm.  my last sportcruiser 2010. I would run at 5400 in cruise and the motors sounded happy. The rotax likes to be run hard I think. The original flight tests by Czech aircraft works in 2004 from rumors were totally different  then what's published now. Also from rumors it was test flown with a Jabiru 3300 engine. I agree with Dave that those limits are long gone or we will never see them. These planes are great and can take a beating. I think we all fly them light and its better in the long run for the airframe life not to mention that anything over 1320 is illegal. All I can say for sure is every time I get into it I'm like a little kid... its a pure joy to fly.

  Also they have a new plane in the works and if you goto czechsport facebook  site and look though the pictures you will see a Grey plane with orange stripes  without wheel pants.  Rumor on that its our plane with a UL motor in it 150hp with a constant speed prop.  I would love to fly that one.

[dnhill]

The following was posted on the Yahoo website back in 2010 from a Swiss member:

 

Hi Peter

Here some more information about my attempt to get an increased MTOW accepted by the Swiss Experimental Aviation Association:

First of all I am building my SportCruiser as a travelling machine, so I want to be able to fly with my wife, full fuel and say 30 kg of baggage. I do not intend to fly 6 hour legs, but full fuel allows me to fly somewhere and back without having to worry about availability of fuel.

With an MTOW of 600 kg minus 80 kg for fuel minus 140 kg for crew (excluding future growth) minus 30 kg for baggage the maximum empty weigt is 350 kg. Most SportCruisers end up being heavier than that, some with the balisic recovery system are close to 390kg. Mine is 367 kg (without BRS, but with leather seats, autopilot and GNS430), which leaves only 13 kg of baggage with the above crew weight and full fuel. 

As we have an experimental category in Switzerland that is similar to the one in the US I am basically free to certify my plane for whatever weight, as long as I can demonstrate it to be safe (which usually means compliance with FAR 23).

First I tried to get engineering data from CzechSportAircraft that proves that the SportCruiser is built for more than 600kg. They do however not have such data, even though they clearly say that the structure is probably fine for 650 or even 700 kg. This is also demonstrated by the fact that all testing, with he exception of the landing gear drop test, has been done to significantly more than ultimate load (6 g), typically 120 to 140% of it. 

The Swiss Experimental Aviation Association does however not accept that, also the calculation has to be done for the MTOW. When discussing with CzechSportAircraft they pointed out that the SportCruiser is certified for 4 g (6 g ultimate), while FAR 23 only requires 3.8 g. 600 kg * 4 g gives 2400 kg, divided by 3.8 g gives 630 kg, so if I reduce the maximum load under MTOW condition to 3.8 g then the existing calculation is sufficient. 

The remaining problem is the landing gear drop test, which has only been done to ultimate load, so the maximum landing weight has to remain at 600 kg. During the Aero 2010 I discussed this with the manufacturer of the landing gear legs and he told me he could make me gear legs for a higher weight, but I can live with the maximum landing weight remaining at 600 kg. 

I am currently waiting for a feedback from the Swiss Experimental Aviation Association on whether they accept my logic, but I know that they have accepted a quite similar case for another plane. I will let you know as soon as I have an answer.

Regards

Bernhard
 

[DavePilot]

There are two topics in play here:

1) how heavy (airplane empty Weight, plus occupants, plus fuel plus baggage) can I fly a CRUZ aircraft and not have a structural failure or flying quality difficulties.

2) how heavy (airplane empty Weight, plus occupants, plus fuel plus baggage) can I fly a CRUZ aircraft and still be LEGAL under the government and regulatory authorities in my country.

My assumption for this post is "if I meet the requirements of topic 2 above (fly Legal), then I will not have an airplane structural failure or flying qualities problem due to overloading the aircraft (Topic 1).

I.e., the presumption is that if we stay below the Maximum Take Off Weight (MTOW) LEGALLY ALLOWED in our country for a Light Sport Aircraft, and of course if before flight we do the proper and normal Weight & Balance checks, and we are a skilled Pilot and are current and proficient at flying a Light Sport CRUZ airplane, then we likely will survive the flight, and not experience unusual flight handling difficulties when the aircraft is not overloaded.

So, I am not going to discuss in this post any speculation as to "how much design margin" is available above the LEGAL MTOW of our CRUZ LSA. That Topic # 1 is a great, interesting discussion topic, and I would love to know "the answer", but it seems a more appropriate topic for a specific flight test to expand the Maximum Take Off Weight envelope above what is legally allowed and specified as "maximum" by our CRUZ aircraft manufacturer.

Since I fly in the USA, I know the USA FAA laws for Light Sport Aircraft.

We with an LSA in the USA must stay below a MTOW of 1320 lbs which is ~600 kilo grams.

But what about Europe or Australia ? What are their legal requirements for LSA CRUZ FACTORY BUILT AIRCRAFT ?

We have SCFLIER FORUM members who live in the U.K. and Australia. I emailed them directly and asked what their laws and legal requirements for flying a LSA CRUZ in their country were.

Here is what they said:

United Kingdom

"Light Sport Aeroplane complies with the following criteria:

A Maximum Take-Off Mass (MTOM) of not more than 600 kg (~1320 lbs)

A maximum stalling speed in the landing configuration (VS0) of not more than 45 knots CAS at the aircraft's maximum certificated Take-Off Mass and most critical centre of gravity.

A maximum seating capacity of no more than two persons, including the pilot.

A single, non-turbine engine fitted with a propeller.

A non-pressurised cabin

These specifications apply to aeroplanes intended for "non-aerobatic" and for "VFR day" operation only.

The airworthiness code is ASTM International standard F2245.

The ASTM standard for Light Sport Aircraft is accepted as a "certification" basis for issuing a permit to fly.
This PTF PERMIT TO FLY has a limited validity, 2 years, and will not be extended when ELA rules are in place in Europe. Limitations will prohibit at least IFR, Night VFR, Aerobatics, and SOLO-Training. Modifications of the Aircraft require a new approval of flight conditions.



There are two different types in the UK, older planes are known as SportCruiser are covered under a LAA permit to fly

http://www.lightaircraftassociation.co.uk/engineering/TADs/338%20SPORTCRUISER.pdf

and the MTOW is stated as 600Kg. (~1320 lbs)

Newer planes are known as “PS28 Cruiser” and are certified to a European specification -again this has a MTOW of 600Kg. (~1320 lbs)

The certified versions have much more restrictive maintenance,
modification and paperwork requirements."

Australia:

"The United States FAA introduced an LSA rule on 1 September 2004. CASA Australian Civil Aviation Safety Authority
intended to harmonise with this rule as much as possible. However, because of the extensive experience with operating similar types of aircraft in Australia, it was decided that minor differences in defining LSA were warranted.

These CASA Australian Civil Aviation Safety Authoritydifferences vs the USA FAA LSA laws are:
•CASA Australian Civil Aviation Safety Authority

allows a (maximum) stall speed of 45 knots in the landing configuration (Vso) whereas the FAA allows a (maximum) stall speed 45 knots in clean configuration (Vs1)
•CASA has no requirements for a propeller whereas the FAA requires the propeller to be fixed pitch or ground adjustable.
•CASA allows a never exceed speed (Vne) for glider of 135 knots whereas the FAA allows 120 knots.
•CASA allows a gross maximum takeoff weight of 600 kg (~1320 lbs) for a LSA, increased to 650 kg (1433 lbs) for float planes
•CASA has no maximum airspeed requirement for a powered aircraft whereas the FAA stipulates maximum airspeed in level flight with maximum continuous power (Vh) of not more than 120 knots CAS (in standard sea level atmospheric conditions)"

Disclaimer: while I did receive credible, consistent answers on LSA legal requirements from multiple SCFLIER FORUM members in both the U.K. And Australia, I (nor they) -are not legal experts in the LSA laws applying to the U.K. or Australia. CRUZ aircraft owners should consult their regulatory agency for Light Sport Aircraft in their individual countries rather than using the SCFLIER FORUM as a legally accurate source of information.

[DavePilot]

Two SportCruiser U.K. Events were forwarded to me by U.K. SportCruiser owners who responded to my question on Maximum Take Off Weight in the United Kingdom:

 

1) There was a kit built SportCruiser structural elevator failure in England. Not related to being over the MTOW 600 Kg weight limit, but a unique restriction on kit-built SportCruisers (Vne reduced from 138 knots to 120 knots) is now in effect in the U.K.

 

The United Kingdom has a Light Aircraft Association called LAA.

 

Here are the comments I received on that single incidence of a structural elevator failure during Vne high speed shallow dive testing, with some extra details (fire extinguisher was "loose baggage in the cockpit", ...problems related to fire extinguisher......a good reminder to all aircraft Pilots to ensure that all loose items are SECURED in the cockpit.... ). The kit built SportCruiser Pilot was able to land safely and successfully.

 

From one of our U.K. SCFLIER SportCruiser owners....."Vne for factory built is 138 knots. however, kit built is restricted to 120 knots by the UK LAA due to (the Kit Built SportCruiser) Vne test that resulted in structure failure of the elevator.....having read the account of the incident I (a U.K. SCFLIER FORUM member) think it was due to pilot error using large control inputs above Vmo rather than a fault with the airframe."

 

2) This news article (another different, second separate U.K. SportCruiser event ) suggests that exceeding 600Kg is not a good idea. One fatal, one seriously injured in this second event. Speculation that exceeding 600 Kg may be a factor, but other factors also may seem plausible...

 

http://www.bbc.co.uk/news/uk-scotland-glasgow-west-32732607

 

Back to event 1) above....More discussion of the structural failure of the elevator in a Kit built SportCruiser while testing Vne in a shallow dive is provided in this second article. See pictures below for this second article.

[ronin5573]

Man ..... how hard did he push forward to launch the fire extinguisher from the center console which his arm was most likely resting on to go through the canopy.  Glad he got it back on the ground.

[rtk]

Man ..... how hard did he push forward to launch the fire extinguisher from the center console which his arm was most likely resting on to go through the canopy.  Glad he got it back on the ground.

 

 

From my read of the article, it sounded as if the elevator folded around 125 knots IAS?  Maybe that folding of the elevator caused the "bang" sound and ejected the fire extinguisher?  

 

Out of curiosity, is there a difference in materials or structure on kit built Sportcruisers versus factory built Sportcruisers?  Wondering why the LAA chose to limit the kit-built version to Vne of 120 knots and factory built remains at 138 knots?

[DavePilot]

An opinion

 

On rtk 's question above re difference in materials or structure ? on kit built SportCruisers vs factory built SportCruisers.

 

And the U.K. Light Aircraft Association (LAA) limiting kit-built to a reduced Vne of 120 KIAS vs the original Vne of 138 KIAS.

 

The SportCruiser kits were supplied by the "original" manufacturer, now bankrupt, called CZAW, Czech Aircraft Works.

 

The SportCruisers built by the factory are now manufactured by the later company, CSA, Czech Sport Aircraft, A.S.

 

It is not unusual for an owner to purchase an aircraft kit, and then take YEARS, sometimes five, ten, fifteen or more years to complete the kit and perform flight test and then fly the completed aircraft. I believe the USA FAA laws related to E-AB Experimental Amaterur Built aircraft kits may be similar to the U.K. LAA regulations related to Experimental Kit Built Aircraft.

 

There are some options on techniques and methods that are legal for an owner building a kit aircraft. If you look at the U.K. LAA directive related to the CZAW SportCruiser kit aircraft sold by a British Company called Sprite Aviation, the LAA lists

 

Mandatory Compliance Items in Section 2

 

and

 

Optional Alternatove Compliance Items in Section 3.

 

See the LAA PDF link in my post above, and the excerpt pictures below of Section 2 and Section 3 details.

 

For example, the Elevator horn reinforcement Service Bulletin is mandatory for CZAW SportCruiser kit builders.

 

But, as an alternative, a newer one piece elevator horn discussed in Section 3 may be used.

 

Also note that some modifications we now see on PiperSports and new production SportCruisers such as the Rotax required fuel pressure vapor return line to the left wing fuel tank is even required by the U.K. LAA on these kit built SportCruisers. Very strict parts and configuration control.

 

So I believe that the U.K. LAA is strictly controlling the parts, structure, and materials of the CZAW kits to match improvements and Service Bulletins that have come out on the production aircraft. The kit materials and structures should match the production aircraft.

 

Yet, For both of the Section 2 and Section 3 options, the Vne speed reduction limit on Knots Indicated Air Speed KIAS is set to 120 KIAS for kit built aircraft, vs the original 138 KIAS that we here in the USA have for production built CSA factory SportCruisers, and I believe even applies with Vne of 138 KIAS for the legacy CZAW factory built 2007-2009 SportCruisers.

 

I don't believe the structure or materials or parts of the kit built elevator stabilizer is significantly different from factory built. Same aluminum skin, same internal structure, same riveted all metal construction. Same upgraded parts such as the reinforced elevator horn or as an option, the NEW one piece elevator horn.

 

My opinion is that the kit quality variation and Vne speed concern from the LAA is the BUILD QUALITY of the "Experimental-Amateur Built" experience level of the builders of CZAW kits. Some of these kit builders may be SUPERB aircraft builders, with extensive kit building experience, excellent tools available, and perhaps even fixtures available to hold the aluminum parts whilst building the aircraft. Some other amateur kit builders may have far less experience resulting in lower build quality.

 

And my OPINION is that the Czech Sport Aircraft production workers are simply SUPERB at assembling and producing all metal aluminum aircraft parts. That is what the Czechs do, and they are famous for high quality aircraft production dating back to WWII.

 

I'll bet that some of (all?) of the CZAW fixtures, tools, assembly jigs, etc., carried over from the bankrupt CZAW company to the new CSA company.

The CSA and CZAW factory built SportCruisers and PiperSports have EXCELLENT BUILD QUALITY.

 

So my opinion is that I would rather fly a production built SportCruiser, with highly experienced riveters using production quality fixtures and jigs and tools, than the expected higher variation in build quality that MAY be found with some amateur Kit builders.

 

If one was a government U.K. Official from the LAA, charged with protecting the public on the ground and also aircraft Pilots, it seems they would prefer the BUILD QUALITY of a production built factory SportCruiser over an amateur kit-built SportCruiser.

 

Just an opinion.

[rtk]

So my opinion is that I would rather fly a production built SportCruiser, with highly experienced riveters using production quality fixtures and jigs and tools, than the expected higher variation in build quality that MAY be found with some amateur Kit builders.

 

 

 

Many thanks for the explanation and history, DavidKarenVV.  I was wondering what the variable was, and I think you may be spot on that it comes down to builder competence and quality rather than materials.  From what I've seen and read of the Sportcruiser, it is indeed a well built and capable aircraft (at least the factory built versions).

[Wjherman]

Wow, great information! I appreciate all of the responses to my query. As a new member to SCFlier, I can already see what a great resource this is going to be!

 

Thanks for your input

John

[ShawnM]

For those that want access to the actual TADS documents for the kit built SportCruiser, to see each individual MOD accepted by the LAA or download any of the docs here's the link:

 

http://www.lightaircraftassociation.co.uk/gcse/search.html?q=tads+338

[Bruzman]

Found this thread today...was wondering if there was any information on the actual structural limits for the Cruiser.  I was considering a Jabiru 230D and that aircraft was designed as a 4-seater, so the aircraft was designed to (I think) a 1600 lb MTOW when it was a 4 seater in Australia. Of course, to fit into the LSA category, they removed the rear seats and published the MTOW as 1320 for US markets.  The airplane still has a rear door, and the cabin is open where the seats used to be.  Given the upcoming possible changes to the LSA requirements in the US, where the MTOW may be raised, and the stall speeds also, I was wondering what will happen to the aircraft that are limited to 1320. Wouldn't it make the Jabiru a better option if one was buying a plane today?  It seems like that plane would simply be able to raise the MTOW to whatever it was designed to carry, making it more useful than the SportCruiser.  Therefore, I was wondering if the SportCruiser was designed to carry a heavier useful load, or if it will be stuck at 1320.  Seems like that would crush the future value of the SportCruisers.     

[ShawnM]

Hi Bruzman and welcome. I've seen the Jabiru you are talking about and yes it was built as a 4 place aircraft. With a little ingenuity they made it fit the S-LSA category. Good for them.

As for the SportCruiser, I seriously doubt that cruiser aircraft will be retroactive with the new rules, whenever they come out, on the existing fleet of SportCruisers. They may "grandfather" in some of the very newest planes but don't hold your breath for it. I also seriously doubt that cruiser aircraft will do anything for the legacy fleet of SportCruisers. It's simply too much liability for them to take on. They can barely keep the doors open at this time and they are having a lot of difficulty fulfilling simple parts orders. And we all know that "R&D" costs a lot of money that they just don't have. If they ever sell a new plane in the US again after the new rules come out it may qualify for the higher MTOW but I'll bet you dollars to donuts that it'll also have a higher MSRP to complement that higher MTOW.  

I personally don't care about a higher MTOW as it wont affect me either way. My legacy 2007 SportCruiser fit's my mission perfectly. 

[Velocity26]

Shawn,

If/when MOSIAC comes out, and eliminates the 1320 limit, would you (as a E-LSA) be able to recertify your aircraft to a higher gross weight limit? 

If you would say, your new gross is 1420 and your new dirty stall is 42 kts, assuming that complies with the new MOSIAC specifications. 

 

[ShawnM]

11 hours ago, Velocity26 said:

Shawn,

If/when MOSIAC comes out, and eliminates the 1320 limit, would you (as a E-LSA) be able to recertify your aircraft to a higher gross weight limit? 

If you would say, your new gross is 1420 and your new dirty stall is 42 kts, assuming that complies with the new MOSIAC specifications. 

As I understand it you can do this with an E-AB (experimental amateur built) and you "the builder" are required to go back into the flight testing phase and notify your local FSDO of these tests. So, since I didn't build my plane the manufacture would have to conduct flight tests and certify that the aircraft is capable of a higher MTOW and I just don't see cruiser aircraft doing this for the legacy fleet. Given their track record I wouldn't hold my breath for them to do anything.

We are all just guessing here at MOSAIC, no one knows what, if anything, will happen with the existing fleet.

Again, none of the proposed changes will change my mission for my SportCruiser. I'm still going to go to pancake breakfasts, fly up and down the gulf coast of Florida and fly around for that $100 veggie burger. This is what I bought the plane for. 

[Velocity26]

Agreed, but indulging in said pancake breakfasts (along with $100 cheeseburgers) are not helping MY gross weight and I need my airplane to grow with me!!

[ShawnM]

On 10/19/2023 at 4:55 PM, Velocity26 said:

Agreed, but indulging in said pancake breakfasts (along with $100 cheeseburgers) are not helping MY gross weight and I need my airplane to grow with me!!

I try real hard to not go back for seconds. Everything in moderation.