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Empty weight differences


Jorge E Trevino

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Good afternoon,
I am a PP student and have been researching LSAs. The CTLSi has high wing and very efficient gas consumption, however EW is 810 lbs, which leave us with only 530 lbs of UL, with full fuel (35 gal @ 6 lb/gal = 210) leaves only 300 lbs for passengers and baggage. My wife and I combine a total weight of 350 lbs (220+130). How can this plane be used for cross country?

On the other hand a CTLS is 770 EW, which will give us  40 xtra pounds of UL, but only 340 lbs for passengers and baggage, still not enough capacity. 
 

Any thoughts?

 

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16 hours ago, Jorge E Trevino said:

Good afternoon,
I am a PP student and have been researching LSAs. The CTLSi has high wing and very efficient gas consumption, however EW is 810 lbs, which leave us with only 530 lbs of UL, with full fuel (35 gal @ 6 lb/gal = 210) leaves only 300 lbs for passengers and baggage. My wife and I combine a total weight of 350 lbs (220+130). How can this plane be used for cross country?

On the other hand a CTLS is 770 EW, which will give us  40 xtra pounds of UL, but only 340 lbs for passengers and baggage, still not enough capacity. 
 

Any thoughts?

 

Full fuel is Cessna mentality. You need to remember that with 20 gallons of fuel you can exceed the average Cessna 172 range, especially with the CTLSi. 

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24 minutes ago, Tom Baker said:

Full fuel is Cessna mentality. You need to remember that with 20 gallons of fuel you can exceed the average Cessna 172 range, especially with the CTLSi. 

^^^  This! 

I almost never carry extra fuel, I usually run 15-25 gallons, and have occasionally taken off for short flights with 10-12 gallons.  The only times I really run full tanks is if I'm doing really long cross country flights and/or think that i might have to divert around weather and want more options.  Shoot for 20 gallons for most flights, that will be 5 hours in a CTLSi at moderate throttle settings.  That right there saves you 90lb, and lets you carry you and your wife plus some baggage.  If you have more bags for a longer trip you could even go to 15 gallons of fuel and just plan a stop every two hours.  A lot of people in many different airplane types have to do that anyway.

The CTLSi is the heaviest CT variant, I think even the new F2 is lighter.  If you are a big person or carry a lot of stuff in the airplane, at legal weights it becomes almost a solo only machine.  But the good news is below 90% power or so it sips fuel like a fashion model with a milkshake, so you don't need much and certainly nowhere near 35 gallons.

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If you are specifically looking for a light sport aircraft, check some of the weights of other manufacturers. You’ll find the CTSW lighter than most, and the CTLSi pretty equal to many others. Also, look at fuel capacity. The RV-12 is very popular, but only holds 20 gallons.

My wife would never sit in the airplane long enough to need to top it off. Still, because it only weighs 736 lbs., we can top it off and have about 20 lbs of baggage. We have made 2 1/2 hour trips, then flown the return 2 1/2 hours without adding fuel, but we could simply add fuel before our return if we needed more baggage.

It’s hard to explain how fuel efficient these planes are, but 34 gallons would give me an easy 5 hours plus reserve. I’ve done some 4 hour legs flying from California to Oshkosh, but while the plane could keep going, I was ready for a bathroom break and lunch!

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One thing is really nice about big fuel tanks:  Even if you don't want to sit in an airplane for 6+ hours, you can also trade fuel for time.  Coming back from Oshkosh I was trying to beat some weather, and I flew a long leg to get home at max continuous RPM (5500) the entire way back.  I only gained a few knots over a lower power setting, but I really didn't want to get stuck behind the weather.  I started with 30 gallons or so, and was able to fly 478nm in a little over 4 hours, and still landed with about 7 gallons.

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Just a thought, if you are just learning, buy your own airplane to do the training in. You are gonna buy one anyway, so save the cost of renting one and use your own for the training. After about 15 hours of training (25 years ago!), I bought my own Cherokee to finish training in. Kept the airplane for about 10 years and 1200 hours before I upgraded. Sold the Cherokee for $10k more than I bought it for too! You also don’t have to fight with finding an airplane available on the schools rental schedule.

One other thought…if you are going to buy a CTLS or other light sport aircraft, get your sport pilot license before your ppl. It is much quicker and will allow you and your wife to fly on your own much earlier. You can use the hours from your sport pilot rating towards your ppl, so you aren’t loosing any training hours towards a ppl. A sport pilot has some limitations compared to a vfr private pilot, but not much. Once a sport pilot is signed off for controlled airspace, I think the biggest loss compared to a ppl is not being able to fly at night. But again, as a sport pilot you and your wife can be out making your day vfr trips while you continue with your ppl training.

Good luck with everything. You’ll love it!

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I have a question for my CTLS pilots friends.

Cruise speed at 75% power for this plane is listed at 115 kts (I assume it represents Indicated speed).

If you fly at 6000 MSL, wouldn’t the true speed be more like 138 kts (ASSUMING NO WIND)?

Or 2% faster per 1000 ft elevation?

Am I missing something?

Regards.

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Jorge, since we don't have a turbocharger on the 912 there is a decrease in horsepower the higher we go.

My experience has been with a 2008 CTLS and now a 2013 CTLSi.  Power settings are based on rpm.  Anywhere below 8k MSL with the CTLSi at 5300 rpm I plan for 118-120 knots at 4.7 gph.  At 5500 rpm, 123-125 knots at 6.1 gph.  I can't really set the rpm anywhere in between since the computer jumps to full rich after about 5300 rpm.  I've flown as high as 10500 MSL and those numbers held pretty close but climb is definitely slow.

Fuel flows were about 1gph more with the 912ULS.  The sweet spot is somewhere around 7k MSL as this is where the 2% increase in speed meets the decrease in powerplant performance.  If it was turbocharged and could make full power at elevation then the TAS would be higher for sure.

There is a forum member here with a turbo CT and if I remember right the TAS numbers are around 140kts.

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