Sport Pilot Talk

drseti wrote:

Mal K9 wrote: If specs for that aircraft is 140 knots, how does it qualify LSA?

Make sure you know exactly what spec you're talking about. The 120 kt CAS limitation applies specifically to Vh. The Vne spec (i.e., redline), for example, can be 140 kts, or 150 kts, or whatever - neither ASTM nor FAA rules specify that.

Gotcha. Thanks for clarifying

Lightning LS-1

Performance
Jabiru 3300
Horsepower
120 hp
Cruise Speed
120 kts TAS
Vne
180 kts
Stall (Full Flap)
38 kts
Glide Ratio
17:1
Take Off Roll
400 ft
Landing Roll
500 ft
Climb Rate
1200 ft/min
Fuel Burn
5.5 gph

And again, the 120 knots airspeed is not a speed limit for the pilot. It is a design limitation.

Note that the LS1 specs listed above don't even mention Vh. They list cruise speed, which is neither defined by ASTM and FAA, nor even an official V speed.

So what is a safe cruising speed for that aircraft if cruise is not defined?

Speeds defined by FAA include Vne (never exceed speed) and Va (maneuvering speed). Normal cruise can be anywhere between those two. Normally, a plane is incapable of exceeding Vne in level flight, but could in a power dive (which would compromise its structural integrity). In the presence of turbulence, to stay safe you want to slow down to below Va. "Cruise speed," like "range," "endurance," and "hauling capacity," are advertising terms which manufacturers will tweak to make the product appear desirable. They may or may not have any factual basis.

Over the past forty years I've owned three airplanes, a 1966 C-150, a 1963 C-172, and my current 2008 CH601XLi-B LSA. None of them have had cruise speeds greater than 120 kn, and I've made several California to Florida round trips in the 150 and the 172 over the years. For my missions 120 knots is fast enough, but I've known lots of guys who aren't satisfied with what they've got (no matter how fast it is) and always want to go faster.

If I absolutely have to go faster or need to carry more people, I can rent a C-182 or a Cherokee 6-300, but I haven't done that since the late sixties.

To me, an LSA provides a great deal of utility and capability, depending on model of course. I have a Flight Design CTSW.

I have taken very long trips. The latest was from Georgia to Michigan. We made the trip in 6.5 hours, which included a 1 hour delay for weather near Cleveland. That compares very favorably with a 16+ hour car trip for the same location.

But because of the stall speed requirements, all LSA are also good at flying slow. I spend a lot of time tooling around at 90-100kt and burning 4gph or less. I land at grass strips and Just have fun. They snappy handling of most LSAs them more fun to fly than a 172 or Cherokee.

For recreational pleasure flying with some longer travel flights mixed in, there are many LSA that are tough to beat -- as long as you can accept the limitations of VFR-only flight and the occasional weather delay

Mal K9 wrote:So what is a safe cruising speed for that aircraft if cruise is not defined?

The 120 knots LSA design speed is applicable for that airplane, just not listed in their specs because it is not pertinent to a pilot. In smooth air, you can cruise as fast as the airplane will go as long as you don't exceed Vne and don't exceed the max rpm limits of the engine.

Scooper wrote:Over the past forty years I've owned three airplanes, a 1966 C-150, a 1963 C-172, and my current 2008 CH601XLi-B LSA. None of them have had cruise speeds greater than 120 kn, and I've made several California to Florida round trips in the 150 and the 172 over the years. For my missions 120 knots is fast enough, but I've known lots of guys who aren't satisfied with what they've got (no matter how fast it is) and always want to go faster.

If I absolutely have to go faster or need to carry more people, I can rent a C-182 or a Cherokee 6-300, but I haven't done that since the late sixties.

I agree 100 percent. For most of us, we fly for the enjoyment of flying. Flying is being in the air operating the airplane, not sitting on the ground bragging about how quickly we got there. To me, the only time airspeed becomes really important is flying into a very strong headwind in a very slow airplane. You may never get there.

Having flown only LSA for the past 6 1/2 years due to no medical, I'm enjoying flying as much or more than when I was flying much faster airplanes. I do miss flying at night (a little), but don't miss flying IFR at 71 years old. I can count on one hand how many times I flew over 10,000 feet, so that's not an issue either. I rarely flew with anyone in the back seat either. Bottom line is LSA and Sport Pilot privileges and limitations will meet the needs of most pilots, IMHO.

TimTaylor wrote:Bottom line is LSA and Sport Pilot privileges and limitations will meet the needs of most pilots, IMHO.

Yep.

My buddy says a back seat is asking for unwanted guests

One very important point that has not been mentioned is indicated airspeed vs true air speed.

The LSA rules are max 120kts CAS or calibrated airspeed which is for all practical purposes the same as indicated air speed.

The Tecnam LSAs with the 914 turbo are quite a bit faster at altitude.

I regularly fly over 130 TAS when above 7500 ft while the CAS is at or below the 120 limit so perfectly legal.

If your looking to go faster in an LSA check out a Tecnam P2008 or Astore with the 914.

Mark Gregor
Advanced Aircraft LLC
507-327-9465

Mark Gregor wrote: The LSA rules are max 120kts CAS or calibrated airspeed which is for all practical purposes the same as indicated air speed.

Well, sort of. CAS and IAS are only the same at sea level, standard temperature, standard pressure, zero humidity, and when the pilot tube is at a zero degree angle of attack. Now, the first four of those conditions are the ones under which Vh is defined. But the fifth one is only achievable with a variable angle pitot mast. Since these planes have fixed-position (not pivoting) pitot tubes, you can't say that CAS and IAS are "for all practical purposes the same." All you can say is that IAS is a close approximation of CAS at sea level under standard atmospheric conditions.

Sorry to be so pedantic, Mark. Not picking on you, just trying to clarify what CAS really means, since most of my students don't get it.

The most important thing to emphasize here is that Vh is a design limit for an LSA, not an operating limit for the Sport Pilot.

Atrosa wrote:Yeah ask those Arion guys about the 120kt limit...

I reviewed the spec’s on the LS-1, which conform to LSA requirements. However, it appears the LS-1, like some other LSA’s can and have been certified at different levels depending on where they are marketed. Take the Sling 2 for example, here in the US it’s MAUW is 1320 lbs. Elsewhere or built as an EAB, it’s 1540lbs. There is no difference in the aircraft, they are identical. It’s all about the paperwork and other factors limiting their performance.