[dspender]

UL makes a 260 and a 350 experimental engine. The 260 has less horsepower output than the 350. In a light sport aircraft, would the cruise speed be comparable between the two engines and only the takeoff run and climb rate be less in the 260 than the 350 or would the cruise speed also be less than the 260?

 

[rvbuilder2002]

UL makes a 260 and a 350 experimental engine. The 260 has less horsepower output than the 350. In a light sport aircraft, would the cruise speed be comparable between the two engines and only the takeoff run and climb rate be less in the 260 than the 350 or would the cruise speed also be less than the 260?

The light sport speed requirement is 120 Kt max at the engines rated max continuous power.

If both engines have the same maximum continuous power rating, then the speeds will be the same.
If the rating is higher on the larger engine, then that engine will be faster.

 

[dspender]

The light sport speed requirement is 120 Kt max at the engines rated max continuous power.

If both engines have the same maximum continuous power rating, then the speeds will be the same.
If the rating is higher on the larger engine, then that engine will be faster.

Thank you. The reason I asked is my nephew has a 1.6 L Buick SUV and I have a 3.6 L suburban and we can both go 90 miles an hour if we want to it’s just it with my larger capacity engine I can get there quicker. I was thinking the same thing may apply to Aircraft engines given his Buick is lighter than my suburban

 

[Snowflake]

The original question was about cruise and climb performance, not about speed at max continuous power though.

Assuming you're at gross weight in either case, and that the larger engine puts out more power, then *in cruise*, with the engines set to the *same power setting*, you'll fly at the *same speed*. In climb, at max power, the larger engine will climb faster. This is akin to your Buick vs. Suburban analogy.

To meet the requirements of the LSA category, you may need to de-rate the larger engine, or limit its power settings, to ensure you don't exceed the 120kt requirement. You may still be able to use max power on the larger engine for takeoff and climb, but would have to throttle back to stay under the 120kt limit. I don't know if the regs allow that.

 

[rvbuilder2002]

The original question was about cruise and climb performance, not about speed at max continuous power though.

Good to know…. Thanks for pointing that out
As you explained yourself, max continuous power speed is an important metric if an aircraft is going to be legal for a Sport Pilot to fly it.
Is a placard on the panel stating max continuous rpm different from what the engine manufacturer specified, enough to meet the speed requirement?
In my opinion, no, so please don’t call me to issue an airworthiness certificate for it.

 

[Jjackh10]

a placard on the panel stating max continuous rpm different from what the engine manufacturer specified

Isn't that essentially what Carbon Cub did with the Titan 340? Something like a max power limit of 5 mins, and a max continuous power. So as the "manufacturer" of an E-AB, could the builder not do the same? Sorry I really don't want to open a regulation can of worms but I am curious lol.

 

[Mel]

Isn't that essentially what Carbon Cub did with the Titan 340? Something like a max power limit of 5 mins, and a max continuous power. So as the "manufacturer" of an E-AB, could the builder not do the same? Sorry I really don't want to open a regulation can of worms but I am curious lol.

NO. Only the engine manufacturer can do that.

 

[Jjackh10]

NO. Only the engine manufacturer can do that.

Got it. So the manufacturer (Titan) is able to slap different stickers on the engines going out the left door vs the right and the world is safer. I love the system! hahaha

 

[AirShowFan]

NO. Only the engine manufacturer can do that.

I've always been curious about this, so, since the conversation has come up and has attracted knowledgeable people...

How much tweaking would I have to do to the engine... Or, how well would I have to understand its engineering... Or, in general, what would I have to do... before I could legally say "This engine is experimental, and I am the manufacturer"?

 

[Jjackh10]

I've always been curious about this, so, since the conversation has come up and has attracted knowledgeable people...

How much tweaking would I have to do to the engine... Or, how well would I have to understand its engineering... Or, in general, what would I have to do... before I could legally say "This engine is experimental, and I am the manufacturer"?

I'm getting sucked into the rabbit hole now hahaha. I don't know the answer to your question, but I suspect short of having some serious CNC equipment and a pile of billet aluminum and steel your not getting there haha.
But the regulation isn't about max power it's about max speed. So if a fine enough propellor pitch was selected you could assure that the plane would not exceed 120kts at any engines max power. Do some of the STOL guys planes with a 300hp snowmobile engine still get registered as an LSA?

 

[Mel]

Be Careful. With all this HP talk going around it would be wise to remember that, if during testing, you aircraft exceeds LSA parameters, i.e. 121kts cruise speed, it can never again be flown by a sport pilot. And if the aircraft is certificated as a S-LSA or an E-LSA, the airworthiness certificate is invalid and cannot be recovered. Remember the rule says that to meet LSA parameters, the aircraft must have met the definition continuously from original certification.

Just stating the rules.

 

[dspender]

Be Careful. With all this HP talk going around it would be wise to remember that, if during testing, you aircraft exceeds LSA parameters, i.e. 121kts cruise speed, it can never again be flown by a sport pilot. And if the aircraft is certificated as a S-LSA or an E-LSA, the airworthiness certificate is invalid and cannot be recovered. Remember the rule says that to meet LSA parameters, the aircraft must have met the definition continuously from original certification.

Just stating the rules.

 

[dspender]

Following along, the LSA rules don't allow night flying or instrument flying. Does the engine self land 30 minutes after the sun sets, or does the plane fly out of the clouds to VFR conditions if the pilot accidentally/intentionally gets into clouds. I know the answer to these is no. However, the plane is capable of either of those restrictions, even though it's an LSA. Therefore, the onus of compliance seems to be the Sport Pilot for night or instrument flying. Would not the onus to keep the speed below 120 kts be similar, if for some chance the plane/engine is capable of sneaking past the 120 kts. It's obvious an RV10, RV9, etc. would have the capability to exceed the 120 kts anytime it wished, and no reasonable argument would allow a Sport Pilot in those planes to argue they comply with the restrictions. But the LSA plane, in many allowable configurations, could sneak above the 120 kts also, though the LSA pilot acknowledges he shouldn't allow it to.

I guess the point of my rambling is many normally configured LSA planes could get above the LSA restrictions, but the FAA says configured normally as an LSA, they shouldn't and the Sport Pilot acquiesces to that compliance by adopting the Sport Pilot certificate.

 

[Mel]

Following along, the LSA rules don't allow night flying or instrument flying. Does the engine self land 30 minutes after the sun sets, or does the plane fly out of the clouds to VFR conditions if the pilot accidentally/intentionally gets into clouds. I know the answer to these is no. However, the plane is capable of either of those restrictions, even though it's an LSA. Therefore, the onus of compliance seems to be the Sport Pilot for night or instrument flying. Would not the onus to keep the speed below 120 kts be similar, if for some chance the plane/engine is capable of sneaking past the 120 kts. It's obvious an RV10, RV9, etc. would have the capability to exceed the 120 kts anytime it wished, and no reasonable argument would allow a Sport Pilot in those planes to argue they comply with the restrictions. But the LSA plane, in many allowable configurations, could sneak above the 120 kts also, though the LSA pilot acknowledges he shouldn't allow it to.

I guess the point of my rambling is many normally configured LSA planes could get above the LSA restrictions, but the FAA says configured normally as an LSA, they shouldn't and the Sport Pilot acquiesces to that compliance by adopting the Sport Pilot certificate.

Where did you see a rule that says a light-sport aircraft cannot fly at night or IFR? I think maybe you're thinking about the sport pilot rules.

 

[dspender]

Where did you see a rule that says a light-sport aircraft cannot fly at night or IFR? I think maybe you're thinking about the sport pilot rules.

I defer to your understanding, Mel. I think your qualifications exceed mine. I presumed as a Sport Pilot, I was constrained to pilot only LSA aircraft, which are configured, whether production or experimental, to comply with LSA restrictions. So, maybe a better question from me, should be is it allowable for me, as a Sport Pilot, to be PIC in planes such as an RV10, as long as I remain within the speed, time of day, passenger, etc restrictions?

 

[rolivi]

I defer to your understanding, Mel. I think your qualifications exceed mine. I presumed as a Sport Pilot, I was constrained to pilot only LSA aircraft, which are configured, whether production or experimental, to comply with LSA restrictions. So, maybe a better question from me, should be is it allowable for me, as a Sport Pilot, to be PIC in planes such as an RV10, as long as I remain within the speed, time of day, passenger, etc restrictions?

There's an easy NO.

Example: Can a sport pilot operate a C-172?

In my simple opnion, a sport pilot cannon fly ANY non-LSA plane by saying "I'll stay low and slow and not carry more than one passenger." There just isn't any wiggle on the "concept" that both plane and pilot must be in the same licensure.

Smart people will be along to educate us all.

 

[Mel]

There's an easy NO.
Example: Can a sport pilot operate a C-172?
In my simple opnion, a sport pilot cannon fly ANY non-LSA plane by saying "I'll stay low and slow and not carry more than one passenger." There just isn't any wiggle on the "concept" that both plane and pilot must be in the same licensure.
Smart people will be along to educate us all.

Not sure what you mean here. A sport pilot can fly any aircraft that meets LSA parameters. It may be a 1946 Piper Cub licensed in the Standard category.

 

[rvbuilder2002]

Following along, the LSA rules don't allow night flying or instrument flying. Does the engine self land 30 minutes after the sun sets, or does the plane fly out of the clouds to VFR conditions if the pilot accidentally/intentionally gets into clouds. I know the answer to these is no. However, the plane is capable of either of those restrictions, even though it's an LSA. Therefore, the onus of compliance seems to be the Sport Pilot for night or instrument flying. Would not the onus to keep the speed below 120 kts be similar, if for some chance the plane/engine is capable of sneaking past the 120 kts. It's obvious an RV10, RV9, etc. would have the capability to exceed the 120 kts anytime it wished, and no reasonable argument would allow a Sport Pilot in those planes to argue they comply with the restrictions. But the LSA plane, in many allowable configurations, could sneak above the 120 kts also, though the LSA pilot acknowledges he shouldn't allow it to.

I guess the point of my rambling is many normally configured LSA planes could get above the LSA restrictions, but the FAA says configured normally as an LSA, they shouldn't and the Sport Pilot acquiesces to that compliance by adopting the Sport Pilot certificate.

It sounds like you are mixing two sets of rules.
The rules for a sport pilot, allow for piloting any aircraft designated as being light sport, or an aircraft that meets the light sport performance parameters. That aircraft can be certified as standard category, experimental amateur built, experimental light, sport, or special light sport. There are additional requirements for a sport pilot, such as not flying at night or above 10,000 feet MSL.
If a private pilot is flying any of those aircraft they can fly at night if the aircraft is properly equipped.

Then there are rules that regulate what constitutes a light sport aircraft. The basic standards are no faster than 120 kts at max. continuous power, stall speed no faster than 45 kts at gross weight with no lift enhancing devices used.(flaps,etc.), Max gross weight of 1320 pounds or less.
There are other requirements, but those are the primary basic ones.

So any aircraft that met those requirements at certification and has always met those met those requirements whether it is certified as a light sport aircraft or not, can be flown by a sport pilot.

The IFR restriction applies to special light sport only because the ASTM’s that light sport is certified under specifically prohibit it.
Experimental light sport doesn’t have that restriction. Nor does any standard category aircraft that meet light sport requirements, as long as those aircraft meet the minimum equipment requirements for IFR.

There is a good chance that this will change in the future. Just like many other rules, for the light sport have been changed over the years.

 

[dspender]

It sounds like you are mixing two sets of rules.
The rules for a sport pilot, allow for piloting any aircraft designated as being light sport, or an aircraft that meets the light sport performance parameters. That aircraft can be certified as standard category, experimental amateur built, experimental light, sport, or special light sport. There are additional requirements for a sport pilot, such as not flying at night or above 10,000 feet MSL.
If a private pilot is flying any of those aircraft they can fly at night if the aircraft is properly equipped.

Then there are rules that regulate what constitutes a light sport aircraft. The basic standards are no faster than 120 kts at max. continuous power, stall speed no faster than 45 kts at gross weight with no lift enhancing devices used.(flaps,etc.), Max gross weight of 1320 pounds or less.
There are other requirements, but those are the primary basic ones.

So any aircraft that met those requirements at certification and has always met those met those requirements whether it is certified as a light sport aircraft or not, can be flown by a sport pilot.

The IFR restriction applies to special light sport only because the ASTM’s that light sport is certified under specifically prohibit it.
Experimental light sport doesn’t have that restriction. Nor does any standard category aircraft that meet light sport requirements, as long as those aircraft meet the minimum equipment requirements for IFR.

There is a good chance that this will change in the future. Just like many other rules, for the light sport have been changed over the years.

Thank you for clarifying these points.

 

[rolivi]

Not sure what you mean here. A sport pilot can fly any aircraft that meets LSA parameters. It may be a 1946 Piper Cub licensed in the Standard category.

I knew I'd need some correction.

What I meant was that if the plane is capable of exceeding the LSA performance limits, it cannot be be flown by a sport pilot by pulling back on the throttle.

It's similar to the BasicMed passenger limit. in the case of the Cherokee Six, some were certfified as 7 seats. Those cannot be flown under BasicMed, even if reconfigured for 6. (At least that was our understanding when the rule came out. I don't have that kind of 6 anymore.