Need Some Help On Picking a "Twin"

[L-39 Driver]

My apologies to the forum.

I just found the multi-quote link - could have used that in the past.

...Then I saw the ROYAL TURBINE DUKE!! Sickest(good) looking airplane I've ever seen!!! Get the Duke, assuming she fits your mission profile.

She is good looking. I remember servicing the Duke, back when I worked at an FBO at Oakland North Field many years ago. It was the hottest looking thing on the ramp, including all of the jets at that time, IMO. That's how much I enjoyed just looking at it back then.

Funny how life sometimes leads you full circle. If you check out the specifications in that link that was given, you will see that they claim a 1,000ft T/O distance to clear a 50ft obstacle! I have not checked the STOL requirements lately, but that has got to be pretty close!

I'm seeing Duke B60's ranging from $170k up to $300K+. So, depending on the conversion/modification costs of the PT6, it might even turn out to be more cost effective than a new 90 (for sure), a used Cessna 425 or a used King Air x90x. I'll be calling them on Thursday to get some details - I'll follow-up here later, of course.

I had a nice long answer to this typed up and then I loss my internet connection and poof it went. Ice vanes are used to keep contaminants (water, ice, dirt, and etc...)from getting into the compressor stages of the powerplant. Located just aft of the intake scoopes...when deployed a small door opens, which due to inertia, causes a small amount of air and contaminants to exit out the rear. Since some of the air that would normally go to the compressor exits with the contaminants, you'll lose maybe 100 psi torque. Not a lot in the grand scheme of things.

I don't know much about that airframe at all - but 100 psi does not read like much. How does that translate into a loss of 15%/15%?

Gee, if 100 psi = 15% reduction in power and the loss rate in linear, then a mere 300 psi reduction would equal a whopping 45%% power reduction - that's almost HALF! How?

 

[KLB]

My apologies to the forum.

I just found the multi-quote link - could have used that in the past.




She is good looking. I remember servicing the Duke, back when I worked at an FBO at Oakland North Field many years ago. It was the hottest looking thing on the ramp, including all of the jets at that time, IMO. That's how much I enjoyed just looking at it back then.

Funny how life sometimes leads you full circle. If you check out the specifications in that link that was given, you will see that they claim a 1,000ft T/O distance to clear a 50ft obstacle! I have not checked the STOL requirements lately, but that has got to be pretty close!

I'm seeing Duke B60's ranging from $170k up to $300K+. So, depending on the conversion/modification costs of the PT6, it might even turn out to be more cost effective than a new 90 (for sure), a used Cessna 425 or a used King Air x90x. I'll be calling them on Thursday to get some details - I'll follow-up here later, of course.




I don't know much about that airframe at all - but 100 psi does not read like much. How does that translate into a loss of 15%/15%?

Gee, if 100 psi = 15% reduction in power and the loss rate in linear, then a mere 300 psi reduction would equal a whopping 45%% power reduction - that's almost HALF! How?

I can tell I haven't instructed in a while. Torque is in foot lbs...not psi sorry for the confusion. From what I observed this morning, deploying the ice vanes reduces torque by 100 ft lbs, indicated airspeed by 5kts, and increases fuel an extra 40lbs/hr.

 

[Gonzo]

The SJ will run about $4,000 per 2,500nm leg at best cruise speed (447kts) in fuel (rough calculation) and take about 5+ hours at $1.60 per nm at cruise altitudes (discounting T/O and climb).

The "right Light Twin" will cost around $1,770 per 1250nm leg at best cruise speed (250-260 kts) in fuel (rough) and take about 4 to 5 hours (depending on cruise altitude) at $1.42 per nm at cruise altitudes (discounting T/O and climb).

So, with the SJ, I certainly spend more, but when time is critical, the weather below FL350 is a serious factor and the range is long (as defined by the mission requirements), then the SJ becomes an invaluable tool at just $0.18 more but at 1.75 times the speed.

You just made my point for me.
Your would need to fly the twin about 19,000 hours to brake even, and that is not counting loss income from the more time in the air.

 

[L-39 Driver]

I can tell I haven't instructed in a while. Torque is in foot lbs...not psi sorry for the confusion. From what I observed this morning, deploying the ice vanes reduces torque by 100 ft lbs, indicated airspeed by 5kts, and increases fuel an extra 40lbs/hr.

Thank you - at first I thought you were flying a Dirigible!

Makes more sense now....

 

[NJA_Capt]

Anyone out there have any SJ30 time. It looks like a pretty nice bird. Impressive stats. If so what were or are your thoughts?

I'm not a fan of the SJ. It was a good idea when it was designed...20 years ago. After a multitude of financial and design problems they produced a jet without a singlepoint fueling system. To me that is just totally unsat. The plane has a single "overwing" style filler port on the TOP of the aft fuselage. Probably the most used item on the airplane besides the cabin door, and they make it inaccessible. It makes you wonder what else was an afterthought. It also has a cabin 4 inches shorter than a small body Citation. Not something I would want to sit in for 2500nm. My plane is over foot taller and wider and I would like more room on a 2500nm trip (and I am doing it :30-45min quicker).

On the light twin, I'd take a Baron any day. I would stay far away from the 58P, to much of a problem child. There is yet another turbine conversion out there, but to me, if you are investing that much in a conversion, you might as well get a King Air.

 

[L-39 Driver]

I'm not a fan of the SJ. It was a good idea when it was designed...20 years ago.

That's interesting, because I thoroughly researched the entire industry of Light Twin Jets and Very Light Twin Jets and ended up being forced to conclude that the SJ was simply between categories with no equal and with better performance in many areas than jets almost twice its size and cost (in some areas).

Ed's idea behind the smaller cabin was increased performance overall, but do it in comfort. That seats are wide and extremely comfortable, if you ever sat in the SJ and the goal was to be able to fly high and very fast to short the "time" spent enroute. It was never meant to compete with Gulfstream wide cabin designs.

The SJ is a great example however, of the problem with trying to certify a new GA aircraft design here in the United States. The SJ went through several FAA Part 23 re-design issues, simply because the rules in the U.S. for certifying new concepts is backwards and that is putting it kindly. They would design something to get through the regs only to have those same regs outdated making the some or most of the design effort for certification a moot point - forcing a re-design. This iterative process is one of the reasons why the project took so long to finally certify.

I've been looking into the FARs Certification process myself for another GA twin jet project and came to the conclusion that I could not spend a billion dollars on certifying a prototype 9,500 lbs MTOW twin jet concept, because I could not find a price point that made any sense from a business model standpoint. So, I've given up on my dream of designing, building and bringing to market a new high-performance two-seat tactical twin jet. (similar to the Javelin jet but larger and with better performance overall).

What Sino Swearingen did ultimately certify was an amazing machine in every respect of the word, given the very harsh realities of U.S. based FAR certifications. When you look at the wing design for example, what you see is a wing loading almost 1.55 times that of the Cessna CJ-3 at about 73 lbs/sqft. Yet, the surface area is only about 190 sqft. and the stall speed is down in the 90 kts range and Vref in the 100 to 107 kts range. No matter how you slice it, that is amazing for an aircraft with an MTOW over 13,000+ lbs! You cannot achieve that level of engineering design without having thought about a lot of little details. There is no other twin jet in the same size category that even comes close to that level of aerodynamic efficiency and engineering thoughtfulness.

As far as long flights are concerned, the SJ was pressurization tested up to 36 psi, but is certified to 12 psi which gives sea level cabin pressure at FL410. No other Light Twin can match that, making the longer trips in the SJ certainly more comfortable from that standpoint. This was not an "after-thought" either. The SJ30-2's original design detail called for this right from the word go - so that speaks again to the level of thoughtfulness that went into the detail design work.

On a hotter than standard day, you will need about 4,100+ ft of runway and at FL410 you will see 460+ kts and sea level cabin and you get there in about 20 minutes. For a VLJ or even an LJ, that's some pretty amazing stuff.

From an owner/pilots standpoint, there simply is no equal right now - included in that is the fact that it is Single Pilot and RVSM certified. So, I will very rarely (if at all) sit in the cabin of the aircraft on a long flight, and I seriously doubt that anyone I plan to fly with will complain about the lack of room.

Still, it is a new player on the market and that will always be enough to warrant caution as well as it should. But, for the single pilot/owner operator who needs speed, high altitude performance, sea level cabin atmosphere, friendly yet useful avionics, low Vrefs, low stalls speeds, good handling characteristics and heart pounding sexy looks at icing on the cake - well, this is one cake that you can have and eat too.

Not everyone's cup of tea and I fully understand that. At the same time however, the SJ30-2 is no design bucket of bolts either. She's built solid with some very smart design elements to boot across a very long, challenging and expensive certification process where tremendous lessons were learned along the way that has only served to enhance the ongoing manufacturing process.

As far as the Light Twin is now concerned, each day I do my research, I find that I cannot shake the utility of the 90. So, right now, the Turbine Duke (Turbine B60) and the King Air x90x appear to be the top two contenders - at this time.

BTW - what are you flying that is in the same weight and size (slightly bigger cabin) category as the SJ30-2 that is 15-18 minutes quicker? The reason I ask is because my research indicated to me that nothing in the same size category was faster, could operate higher, take-off slower, be landed slower or fly further -for anywhere near the same price tag. For, me those things make it a very special VLJ. Especially, when the landscape is ripe with failed VLJ projects across the board.

 

[NJA_Capt]

BTW - what are you flying that is in the same weight and size (slightly bigger cabin) category as the SJ30-2 that is 15-18 minutes quicker?

I'm nowhere near the same weight category. I fly the Citation X....not exactly a comparison. As you mentioned, the SJ is pretty much alone in its market. It is has more complex systems than is normally wanted in a LJ/VLJ, such as slats, trimable stab, hyd ground steering, stick pusher etc. Those things are way more complicated (ie....mx intensive) than most owner pilots want/need. I'm still scratching my head on the lack of single point fueling. Engineering thoughtfulness?? They had 20 years. For that amount of time, they could have eliminated some of the complex systems and saved some weight and complexity for their single pilot target buyers. And in doing so, eliminated some of their lengthy certification delays. Hyd steering in a light jet??? Why?

Another thing you have to ask is who is going to support it from a mx standpoint? Without a network of support facilities, it is going to be hard to find someone to work on it if something happens away from home base.

For comparisons sake. The Citation X has about the same Vref speeds as any of the "small" Citations. Landing ref at light weight is 95 KIAS (115 typical). A no flap landing is around 145 KIAS. Mach .92 without a stick pusher/puller.

 

[L-39 Driver]

I'm nowhere near the same weight category. I fly the Citation X....not exactly a comparison. As you mentioned, the SJ is pretty much alone in its market. It is has more complex systems than is normally wanted in a LJ/VLJ, such as slats, trimable stab, hyd ground steering, stick pusher etc. Those things are way more complicated (ie....mx intensive) than most owner pilots want/need. I'm still scratching my head on the lack of single point fueling. Engineering thoughtfulness?? They had 20 years. For that amount of time, they could have eliminated some of the complex systems and saved some weight and complexity for their single pilot target buyers. And in doing so, eliminated some of their lengthy certification delays. Hyd steering in a light jet??? Why?

Another thing you have to ask is who is going to support it from a mx standpoint? Without a network of support facilities, it is going to be hard to find someone to work on it if something happens away from home base.

For comparisons sake. The Citation X has about the same Vref speeds as any of the "small" Citations. Landing ref at light weight is 95 KIAS (115 typical). A no flap landing is around 145 KIAS. Mach .92 without a stick pusher/puller.

I like the Citation X from a pure performance standpoint and from its design utility standpoint as well. It does what it should do, what it was designed to do and it does it very well. However, it is not single pilot certified (of course), larger than I needed personally and would have cost me something in the range of $22.5 million (depending on internal config). So, I would absolutely agree, the SJ and the X are definitely not in the same category by design. How many owner/operator/pilots are there in the X?

The SJ is technically an LJ. In that category of jet then, it has a price tag in the $6 million range which makes it 73% easier to acquire than the X, which is a demonstrated MJ. Yet, on the speed question, the SJ cruises at 90% of X's max cruise speed (at FL310 ISA) and has a range which is 81.43% that of the X as well. It has better short-field performance as well, which opens destination doors that might be closed to some X flights.

So, as an owner/operator/pilot who needs high-speed, high-altitude, long range, maneuverability and relative comfort for one person on most flights, there simply was no other intelligent choice "if" maximizing all of those dimensions of "need" (requirements) were at play at the time of purchase. As far as the maint. is concerned, if you've ever owned an aircraft before, then you already know that you pick the facility that you are most comfortable with and stick with it for the most part. Sino Swearingen has committed itself to being there if owners needed assistance in the "field", so I'm fairly comfortable with the maint. issue. Certainly regular scheduled maint. is not going to be a problem.

20 years is a long time - for Boeing, or Lockheed. But, for a company the size of Sino Swearingen, when you compare the SJ to other aircraft that try to approach the same performance but come up very short, you resolve the reality that what they did was a nothing short of a miracle. If Northrop had taken 20 years to produce a 13,950 lbs MTOW Light Jet, regardless of the super performance for a jet of that kind, I’d look at that as being pretty strange at a minimum. They did all of this in 310,000 total sqft of space and between 300 to 400 employees.

The complexity of the wing design using full-span leading edge slats and full-range flaps was necessary in order to reduce stalls & Vrefs across the board and make the aircraft manageable in the pattern and on approach down to minimums – where you want an airframe that is stable without being too hot to handle, yet maintaining good energy, lift stall characteristics throughout the landing phase. They did a great job of this, and I don’ see any problems in learning the SJ systems going forward. In fact, during my “test flights” I was amazed at just how easy it was to operate the SJ regardless of the flight regime.

Certification of a new aircraft concept in the U.S. is not an easy thing do. It is a massively complex process with many levels of detail that most people don’t fully understand or appreciate. Depending on how the process goes for the full 9 yards, you will find things that “work” but could designed in a different way. If the results you are likely to obtain are marginally better at best, then you will most likely opt to leave the design as it is, because it works perfectly fine anyway.

When you stop to think about what the SJ is and what it was designed to accomplish and who it was designed to serve (flown by a single pilot in RVSM above FL410 at Mach 0.83 in sea level cabin comfort with a Vref of 105 kcas in all weather) then it is hard to not fall in love with the aircraft, just based on that alone.

Not an X, no doubt – but it was never designed to be an X type airframe. It was designed to serve that pilot who wants X-like performance without the X-like price, all under single pilot control. At only 23% the cost of the X, it produces an average of 81.72% the performance of the X. Heck! If that takes 20 to produce by 300 to 400 people, then so be it – I’ll take that ratio of economy-to-performance any day of the week, if I’m a single pilot guy looking form some medium biz jet “like” performance. Remember, I only have one passenger to satisfy on most of my trips (Wife), so the SJ was a perfect match. However, the X is a very nice aircraft given what it was designed to accomplish.

 

[NJA_Capt]

You sure did a lot of comparing between two planes we both agreed were not "comparable."

Maneuverability at altitude in the L39 I can see. Why it is so important for the SJ I don't understand. As I stated, there seems to be a preponderance of "complicated" systems for a SP airplane. Many of which could have been designed out. Others systems which are considered "standard" on jets, are strangely absent on the SJ (such as single point). Regardless, it sounds like you have researched the plane and are confident in its mission. Good luck with your purchase

How many owner/operator/pilots are there in the X?

I can think of two high profile ones off the top of my head and I'm sure there are others. I wouldn't recommend it as a O/P airplane. We have several of our owners who are typed in the X. They may fly their own flights with an NJA instructor pilot, and they attend FSI recurrent with NJA line pilots.

Before anyone asks....yes it is union and company approved as long as it meets company conditions. NJA line pilots are exempt from flying with owners and the normal "FO" is not obligated to ride in the back while an owner is flying.

 

[WacoFan]

LOL - :rawk: Thanks, WacoFan!

This is exactly what I had in mind. Small, powerful, fast, agile, useful and purpose built. I will definitely be calling this company on the phone - I did not check but I hope they are U.S. based.

Awesome link - very helpful and YES, I've always thought the Duke had sex-a-ppeal to spare! The overall geometry from nose to tail has always been a favorite with me, but the power has always been a problem with the NA powerplants. With the PT6, I'm sure she smokes nicely - :bandit:

Do you know anything about Duke handling characteristics, by any chance? Historical design issues?

Thanks again for the lead!

You've got to be kidding me - sweet/sexy/hot Twins - lol! Luv-it, thanks.

L39 - You are very welcome. Fell in love with Duke's (the looks) a long time ago. I am not aware of any specific issues with them - other than the engines, runway usage heavy/hot, etc. It seems that Beech did use some kind of strange metal on them - magnesium or something - and that was a quirk although I am not sure that is a "negative". I may be confusing this issue with another plane - not sure.

The Turbine Duke will not be as common as the KA90 and will be substantially faster. Plus - it is the aerial equivalent of the Bad Ass 55 Chevy Harrison Ford drove in American Graffiti - the Duke plain rocks.

Let me know what you find out - I am extremely curious.

 

[frog_flyer]

L39, if you get a turbine duke, I'll buy you a beer.

I don't care how much money you make, everyone loves free.

 

[Polar742]

I know you want a new airplane, but the Turbine Commanders may also fit the bill. I know you are concerned about the size. With either Byerly Aviation in IL or Eagle Creek Aviation in IN, they both refurb and repower airframes. While not a particular fan of the TPE331's, I think the -10 or -12 installed on the commander, loafs along at altitude. They are very FLAT rated, which would help out in high density situations. They only weigh about 7k at takeoff, have a lav. An added bonus is Ram's horn yokes rock.
http://www.byerlyaviation.com/new_sidenav/renaissance.htm http://www.eagle-creek.com/turboprop/tp_tc_expert/tp_tc_info.html

If I had the scratch, and wanted a single-pilot twin engine ride, it'd be the KingAirE/F90 or a Commander w/-10s. Best of luck

PS: I don't know if you're a member of the NBAA, but they are an EXCELLENT source of knowledge on range profiles, requirements and whatnot.

 

[WacoFan]

TURBINE DUKE!

I am emotionally invested in this now L39 - I must find out what you have learned of the turbine Duke and what you think. Also - since I gave you the heads up, will you let me choose the paint scheme?

 

[trafficinsight]

L39 - You are very welcome. Fell in love with Duke's (the looks) a long time ago. I am not aware of any specific issues with them - other than the engines, runway usage heavy/hot, etc. It seems that Beech did use some kind of strange metal on them - magnesium or something - and that was a quirk although I am not sure that is a "negative". I may be confusing this issue with another plane - not sure.

The Turbine Duke will not be as common as the KA90 and will be substantially faster. Plus - it is the aerial equivalent of the Bad Ass 55 Chevy Harrison Ford drove in American Graffiti - the Duke plain rocks.

Let me know what you find out - I am extremely curious.

Yes, the entire tail section is made of magnesium, Beech did it to reduce weight and keep the same strength... unfortunately magnesium is highly susceptible to corrosion so make sure you look VERY CLOSELY for it during your pre-buy. Also, if you're going to have your Duke converted by Royal Turbine it needs to meet some criteria for them to do that so make sure you do your research first.

 

[SIUAv8r]

Cessna 310, or if you want high alt. C 340 or 414. I'd stay away from the 421, the one I used to fly was in the shop a lot.

 

[SpiraMirabilis]

Thanks for the input - that's what this post is all about!

The ASE trip was just an example (a real one) used to set the performance requirements that I would need, to help frame the discussion and lead to the correct Twin. ASE was also at the very extreme limits of what I defined as my "Medium Range" type mission based on where the aircraft would hanger-up. So, if the SJ were in for maint. and the flight needed to happen, I don't want my other option to be only NetJets or Flight Options. I'd like to be able to fly that mission myself. Thus, the Twin would have to bee comfortable making that kind of trip possible.

The original list of aircraft that I contemplated were the DA42 and the Baron. Both of them would do well (IMO) on the short-end of the Medium Range mission profile at low density altitudes and not much weather. However, I quickly realized that they would not work well on the long-end of the Medium Range mission profile extending out to 750 nm and high density altitudes.

So, with that in mind, the King Air 90x came into focus - thanks to help from people on this board as well as the Aerostar. I wanted to buy "new", but it does not look like that is going to happen at this level. With the ideas on the Aerostar and the 90, I have since expanded my search to include the Cessna 425 Conquest I. Yet, ANOTHER airframe that I complete forgot about for various reasons.

The Conquest I, seems to meet my requirements very well in many areas: speed, range, altitude capability, pressurization, maint., aircraft sizing, single-pilot and it can also be RVSM certified. Quite frankly - I like it after taking a harder look at it! Again, thanks to this site.

Most of the Conquest I's that I've seen thus far, have been kept in very good condition and the PT6A-112 is said to be "bullet proof", by some. The Aerostar seems to have undergone something of a checkered past and many non-OEM modifications to get it to "fly right", according to some. However, according to what I can read thus far, the Conquest I, seems to have been well built for its mission.

So, yes - this has expanded beyond the DA42 and the Baron - in fact, those two are no longer even in the running given the Conquest I and 90.

Both the 90 and the 425 use the same "baseline" turbine with the King Air having access to new variants (I think). The 425 is slightly smaller, which for me is good, because both already have plenty of cargo and pax room. Both seem very similar in performance, with the 90 having what appears to be more "speed mod" upgrade options depending on where you go for that kind of work.

What do you guys think about throwing the Cessna 425 Conquest I in the mix? How would you rate against the 90? Same, worse or better - given the way I intend to use it?

I've flown a Cessna 421 (1984 model?) which is kind of like a 425 except its piston. It was really really nice. It got up to FL250 no problem and cruises at about 225kias or so. If you can find one of these it may be a more economical option than a turboprob like the 90 or 425 yet still provide you with acceptable performance.

 

[SpiraMirabilis]

Cessna 310, or if you want high alt. C 340 or 414. I'd stay away from the 421, the one I used to fly was in the shop a lot.

if you get a 310 make sure its got alternators and not generators. sheesh, I remember those generators being annoyingly always breaking.

 

[CK]

I fly a 425 that is currently for sale.

http://www.controller.com/listings/...758.htm?guid=CAC4C2F80326430D80826CA3B497727C

I think the airplane suits your mission perfectly. The airplane was made for the owner/pilot and is extremely simple to fly and very cheap to operate. The operating cost are approximatly $490 per hour (compared to nearly $900 on the King Air 200 and $650 on the 90). RVSM would be a waste, the plane doesn't like going above FL250. The speeds are 250kts true at FL210 and 400pph, or 260kts at 460pph with a total of 2400 pounds of fuel. I think the Conquest beats the pants off the C90 in all aspects, if it didn't we would have bought a C90 to begin with! The inspections on any King Air are horrible and it seems like they are always in the shop. The speeds on the earlier King Air 90s are a pathetic 220-235kts burning 20% more fuel than the Conquest.

The problem with the Turbine Duke is fuel capacity. The piston duke was only a four hour airplane at 40 gallons per hour. At 80 gallons per hour down low and 60 gallons per hour up high, your range is not going to be all that great.

Let me know if you have any questions.

Alex.