Dream plane

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newamiga
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Re: Dream plane

Post by newamiga »

I spent a lot of time looking at the various models and flying some before buying my LSA. I learned and got my SP certificate in the Gobosh 700 and it was easy for me to say I wanted to own one. I got lucky that one came available from a guy who had put less than 100 hours on it and kept it in almost new condition. So, I would say I got my first choice and I still really like that plane. As I look at other models and if the money were to not be any issue I would also buy the Bristell. It is a great looking plane, nice usefully load and has a lot of room in the cockpit. The only question mark is its performance out here in Colorado. We had a Piper Sport in our flying club for a while and it just had issues on climb out at the higher altitudes and DA out here. My Gobosh has none of those issues. The theory was the win design on the Piper Sport caused issues. It is unclear to me how similar or different the wing on the Bristell is.

I also really like the Carbon Cub. That one is interesting as although it is relatively expensive compared to some LSA's, I think it is more of a standard aircraft that can be flown as LSA. The fact that it is produced on a part 23 line also makes it more worth the extra cost to me too.

The guilty pleasure is for sure the FK-12. It looks great and with the fully aero engine sounds really fun.
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CharlieTango
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Re: Dream plane

Post by CharlieTango »

I would keep my 2006 CTSW because of the 719lb empty weight and its a nice flying airplane.

For the unlimited money I would upgrade my brakes and my panel and would trade out the 912 for a 914i. 150+ kt legal lsa cruise would be sweet. I cross the Sierra sometimes in an Europa with a 914 and 16,000'+ gives nice terrain clearance and speed.
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Re: Dream plane

Post by drseti »

CharlieTango wrote:I would keep my 2006 CTSW because of the 719lb empty weight and its a nice flying airplane.
The lower empty weight is the chief advantage of composites in the LSA universe. The other much-touted reason for going composites (sleeker, more aerodynamic, hence faster) is hardly a factor in the LSA category, where we're limited to 120 kts.
would trade out the 912 for a 914i
When I took my Rotax heavy maintenance renewal course in October (from Dean Vogel at Lockwood Aviation), we got a good close look at the injected 912iS. We also reviewed the 914, which, though turbocharged, is still carbureted. I asked Eric Tucker of Rotax whether there was going to be a version with both injection and turbocharging (i.e., a 914i), and unfortunately he said there would not be. :cry:
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CharlieTango
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Re: Dream plane

Post by CharlieTango »

Can't blame Eric for not spilling the beans.
drseti wrote:The lower empty weight is the chief advantage of composites in the LSA universe. The other much-touted reason for going composites (sleeker, more aerodynamic, hence faster) is hardly a factor in the LSA category, where we're limited to 120 kts.
I would find that persuasive if most LSA could cruise at 120kts but very few can.
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Re: Dream plane

Post by drseti »

CharlieTango wrote:I would find that persuasive if most LSA could cruise at 120kts but very few can.
I suspect that the slower cruise speeds of most S-LSAs have less to do with airframe aerodynamics than they do with prop choice (and how the prop is pitched). After all, there are E-AB versions of the same planes that are faster, with builders choosing to sacrifice takeoff and climb performance for improved cruise speed. And, some of the LSAs are slowed-down versions of significantly faster certified aircraft, where the prop pitch has been deliberately increased (or RPM redline decreased) to meet the LSA spec. It's just that a few of the composite planes have seemed to find the sweet spot. :)
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CharlieTango
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Re: Dream plane

Post by CharlieTango »

drseti wrote:builders choosing to sacrifice takeoff and climb performance for improved cruise speed.
You have said this before but you have it backwards. First we have to establish that the various SLSA manufacturers tend to pitch the props on their 912s too coarse. It has been quite typical to see these props so coarse that 5,800 or even 5,500 RPM cant be reached at WOT even at sea level let alone at 7,500' where cruise speed is best.

Unless you can achieve those RPM and higher optimizing for climb means to flatten the pitch until you can achieve the limitation ( 5,500 makes more sense than 5,800 for most of us ) This meant for me, and everyone else that I have heard of to date, a need to flatten the pitch which optimzed climb and allowed me to cruise faster!

The truth is the airframes make a substantial difference ins SLSA speed. The range being over 20kts.
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Re: Dream plane

Post by drseti »

CharlieTango wrote:You have said this before but you have it backwards.
Oops -- my careless mistake. Thanks for correcting it (again).
flatten the pitch which optimzed climb and allowed me to cruise faster!
FWIW, when I installed new blades last year, I pitched my prop for 5500 RPM at WOT, level at 2000 ft, and seem to get the best of both worlds. This seems to validate what you're saying.
The truth is the airframes make a substantial difference ins SLSA speed. The range being over 20kts.
Yes, some of the designs are very draggy, and slow. But, I'm not convinced it's all about composites vs. metal. For example, my early SportStar (with the high bulbous canopy) is certainly slower than the newer ones with the low canopy. Other than the plastic bubble, it's the same wing and airframe.

Some of the sleeker metal designs (the Bristell comes to mind) seem to me just as fast as the composites. So, I still maintain that (for these relatively slow aircraft, where drag is not the dominant consideration), the chief advantage of a composite airframe is that it's lighter.
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CharlieTango
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Re: Dream plane

Post by CharlieTango »

I agree its not primarily composite vs metal. I suspect low-wings pay a penalty but one that can be overcome but generally is not.

I agree 5,500 WOT is your better compromise, 5,800 is only use full for the initial climb and I wouldn't want to sacrifice cruise speed for a few minutes of benefit considering that 5,500 RPM climb works so well. Plus as you said before less over speeding worries.
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zaitcev
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Re: Dream plane

Post by zaitcev »

A few of the low-wings address the interference drag by having the spar passing under the seats just so the belly of the airplane protrudes down. This way it works just like the fairing on the new "pregnant" buzjets, and overall they meet the drag of high-wing designs.
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Re: Dream plane

Post by drseti »

I wondered why they had that bulge, Pete. Thanks for 'splaining it to me!
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MackAttack
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Re: Dream plane

Post by MackAttack »

Resurrecting this thread, if folks don't mind, as I'm in the market ATM ... Being more of a low-wing fan, I found this thread interesting and wondered if folks still had any thoughts around this topic. On the low-wing side, I'm considering the Bristell and the Tecnam Astore (which was just coming out when this thread was active). Two very attractive and fast aircraft, high fit/finish and expensive when completely kitted out. At the opposite ends of the empty weight spectrum (720 vs 820 or thereabouts)... I realize there are lots of great low wings out there (SportCruiser, RV12, Evektor, etc...) No disrespect to any of them, but I think (based on paper research and flying the left seat of my sofa vigorously!!) that the Bristell and Tecnam reflect the latest design thinking.

Thoughts on engine selection (912 iS sport vs 914 turbo)? Turbo is much heavier, but delivers full performance in climb and cruise to altitude. I am based in Houston where DA is an issue during the summer and getting to cool air QUICKLY is a big deal, not to mention missions to West Texas or elsewhere along the Gulf Coast, so leaning towards the turbo, although I realize fuel economy is less and there is likely more MX.

Chute? No Chute? Another 37 pounds ... I won't even bring up the 40 pounds for the Flycool air conditioner ... But I could literally cram all of those options in a Bristell and come in at about the empty weight of the Tecnam.

On speed, I am hearing that with the turbo or the 912iS and the prop set to max cruise, top speeds for these aircraft are in the 125-128 range ... Anyone have a view on that?

Thanks in advance for all the incoming!

PS- Not overly concerned about flying 6-hour legs; my "personal waste disposal systems" won't really lend themselves to that, so am not freaking out if I can't take 2 adult males and fuel fuel ...
Cluemeister
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Re: Dream plane

Post by Cluemeister »

MackAttack wrote:Resurrecting this thread, if folks don't mind, as I'm in the market ATM ... Being more of a low-wing fan, I found this thread interesting and wondered if folks still had any thoughts around this topic. On the low-wing side, I'm considering the Bristell and the Tecnam Astore (which was just coming out when this thread was active). Two very attractive and fast aircraft, high fit/finish and expensive when completely kitted out. At the opposite ends of the empty weight spectrum (720 vs 820 or thereabouts)... I realize there are lots of great low wings out there (SportCruiser, RV12, Evektor, etc...) No disrespect to any of them, but I think (based on paper research and flying the left seat of my sofa vigorously!!) that the Bristell and Tecnam reflect the latest design thinking.

Thoughts on engine selection (912 iS sport vs 914 turbo)? Turbo is much heavier, but delivers full performance in climb and cruise to altitude. I am based in Houston where DA is an issue during the summer and getting to cool air QUICKLY is a big deal, not to mention missions to West Texas or elsewhere along the Gulf Coast, so leaning towards the turbo, although I realize fuel economy is less and there is likely more MX.

Chute? No Chute? Another 37 pounds ... I won't even bring up the 40 pounds for the Flycool air conditioner ... But I could literally cram all of those options in a Bristell and come in at about the empty weight of the Tecnam.

On speed, I am hearing that with the turbo or the 912iS and the prop set to max cruise, top speeds for these aircraft are in the 125-128 range ... Anyone have a view on that?

Thanks in advance for all the incoming!

PS- Not overly concerned about flying 6-hour legs; my "personal waste disposal systems" won't really lend themselves to that, so am not freaking out if I can't take 2 adult males and fuel fuel ...
Hey Mack,

This sounds strangely like the loop of thoughts in my head over the last 6 months! A few thoughts:

- The Bristell weight is very attractive. It's like they took the Sportcruiser (Milan Bristell's previous design) and shaved weight off it. I think their claim is the metal is in several different thinner thicknesses on the aircraft, and this leads to lower weights. I did not, however, ever check an actual weight and balance sheet on a loaded Bristell. I'm guessing you're still going to come under the weight of the Tecnam, but I would be surprised if it was 100 lbs. If you don't mind asking them, I would be very interested on the actual w&b of the 912is loaded like the one they had at Sebring.

- On the engine, I've found the 912ULS weight is your baseline, and then the turbo and fuel injected are both about the same weight, another 25-30 lbs above the ULS. The Rotax website shows the engine weights by themselves, but there is additional installation structure required.

- The Chute on the Tecnam P2008 is the Galaxy 600. I believe it weighs about 28 lbs by itself, and I think there's another 4 lbs of framework on the aircraft. I'm guessing you'll be closer to 32 lbs on the chute. If you have about a year, you can read every debate ever written about the pros and cons of parachutes on airplanes!

- I've spoken to Turbo P2008 owners, and they all rave about the 914 engine. Of course, there's a cost to go with that. Fuel injected is nice because of the fuel savings and no carbs to deal with. The 912ULS is nice because of the lower weight, and lower price. I personally would like one engine that combines the weight and cost of the 912ULS, the fuel consumption of the 912is, and the power of the 914!
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Re: Dream plane

Post by MackAttack »

Thanks, Clue!

Agree that the 912iS and 914 weights are approximately the same, according to the Rotax website (when you add all the weights up that they have on the spec sheets). My chute weight was just based off the various order forms for Bristell and the Astore; I think the latter uses the Magnum 600 or 620 chute ... plus I looked at both the BRS and Magnum websites for the weights.

I get the chute debate is voluminous; but was more curious about how folks on this forum came out if they had the option...

And if they made that dream engine, things would be great! The new 935 is supposed to be a good solution but I think that's going to be too heavy for the US-LSA market, unless the weight limit is raised or the FAA creates the new "simple, level 1" Part 23 certification rule and lets sport pilots fly those aircraft.

That's an interesting proposed rule, essentially creating a simpler-to-certify category in Part 23 that corresponds roughly to the EASA CS-VLA certification (2 seats) but no weight limit or speed limit (although they may not allow retractable gear, they would probably allow a CS prop). 45 kt max stall speed, VFR only. These aircraft would have to go through Part 23 but it would be quicker, but they couldn't rely on ASTM self-certifications like the LSA rule.

I commented on the rule-making - comment period closes in May. My comment was "this is all great if sport pilots can fly them, or PPs without a medical;" I suggested that as long as a sport pilot got an endorsement from a CFI they should be able to fly this group of aircraft too under a sport license because the safety risk is essentially the same as an LSA. We shall see ...

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Re: Dream plane

Post by Nomore767 »

' Fuel injected is nice because of the fuel savings and no carbs to deal with. The 912ULS is nice because of the lower weight, and lower price. I personally would like one engine that combines the weight and cost of the 912ULS, the fuel consumption of the 912is, and the power of the 914!'

Personally I don't believe the 'fuel savings' of the 912iS is that great. I spoke with a guy who had one and said the gph was about 3.5 at around 5000rpm which is low power for a Rotax. He said he got about 4.1 gph at cruise. I usually plan for 4.4 gph in cruise at about 5300 rpm 912ULS and based on fuel bought and used its been a reliable number.
Even if the overall savings are the 10% that Rotax touted thats a savings of about 25 cents per gallon on the 93 E10 I've been using lately. I've been getting consistently 4.4-4.5 mph on my 912ULS so moving to a 912iS saves me maybe a $1.12 per hour...maybe. In return it costs about $18-19k more to buy plus the extra weight so net the 912iS engine is all more money. The fuel 'savings' makes little difference and the maintenance likely bit more complicated. The additional 10 hp isn't needed for me personally.

The carbs have been a non issue for me in 220 hours of LSA flying in the past 18 months since new. Other than the issue with the carb floats which has been resolved (at no cost to owners since Rotax rebated the cost of new floats) I've only had to have the carbs balanced and inspected which was a simple task for my mechanic at a routine oil change.
The carbs versus injected is a good discussion and injection is the way of the future but for light sport flying the 912ULS has proved to be very reliable. My Rotax trained and qualified mechanic said he has yet to see a 912iS engine in for service or maintenance, although he's qualified to work on them.

I've flown the 912ULS, 912iS and the 914 engines. In the end I chose an airplane with the 912ULS over an LSA equipped with the iS engine. At the time when I almost bought an LSA with the iS engine it required an upgrade and would have required extensive service done on it as well as down time. Another reason I decided against it, again my personal preference.
The 914 engine is very smooth. However, my LSA's ULS engine provides ample power to fly up the light sport ceiling. I've had the airplane up to 9500' out west after picking up the airplane and it proved more than sufficient power for my mission. The airplane is ready to fly about the time the throttle reaches full power with no flaps, and climbs even better with half flaps.
I would say the engine could be considered at higher, warmer, airports like those in the West but again, for me personally, the extra cost and weight far outweighed the benefits and would actually encroach on my mission in terms of reduced useful load.

Rotax have a new engine coming the 135hp 915iS and it'll be interesting to see how that's deployed in the fleet.

Just my two cents and my own personal experience.
MackAttack
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Re: Dream plane

Post by MackAttack »

Nomore, did you wind up with the Sirius 3000 about which you posted a while back? If so, how did you spec it out? Empty weight? Apologies if you posted this elsewhere and I missed it ...

On your other Sirius thread, you observed the difference between sales people quoting figures but not the trade-offs. I will say that the Tecnam person with whom I spoke was COMPLETELY clear about the empty weight, payload, useful load trade offs in connection with the Astore and P2008 discussion we were having ... He was very clear that flying with two adults necessitates about a 3-hour range to be under 1320 and that the max range figure was a single-occupant figure. Should I wind up going with one of those, I will know what I'm getting into. And I will also say that there are a few LSAs which cruise at or near 120 knots and have a pretty stout useful load (e.g., the Bristell).

Re the 914 and density altitude, here in Houston during the summer, density on the ramp can be 2500-3000 feet on a 95-degree F and humid day. So a normally aspirated engine will suffer performance and climb rate loss even in a near-sea-level environment. And that's why I'm leaning towards the 914.

Cheers!
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