How is the twins market ?

[GRG55]

Not really. Stall on a single-engine Comanche is 53 knots, on the Twin Comanche it's 61 knots. 8 knots difference, to me, is not "a hell of a lot slower" even if you multiply by 1.3...

Plus, single-engine service ceiling (the thing most people focus on) is not an altitude which you can't operate above without both engines running. It's the altitude at which you can *climb* 50 feet per minute on one engine. Using a stock non-tip-tank-equipped Twin Comanche as the example, the single-engine service ceiling is 5800 feet, but the single-engine absolute ceiling is 7100 feet. But again, that doesn't mean that you can't fly above 7100 feet with one engine out. 7100 feet is the asymptote of your altitude vs. time after engine failure graph.

Let's say you're over the Rockies at 15,000 feet and lose one. You get it boxed up and trimmed for single-engine flight, and you will be coming down... But your "glide ratio" will be much better than that of a single because you do still have some power, and as you descend and gain more power, your "glide" is extended. Unless you're in a box canyon, you should be able to find yourself an airport before you meet the ground.

The difference in stall and landing speeds? No, not at all. I don't think that has hardly anything to do with the twin safety record - It's pilots who don't train, practice, and plan ahead for the engine failures that cause twins to have a less-than-expected safety record, not airspeeds.

I would also point out the single engine service ceiling figure is based on the airplane being in a clean configuration, critical engine inop, prop feathered, at gross weight. This last item is critical. I have just under 1900 lbs of useful load. Whenever I am going over the Divide I keep the plane light; it is never anywhere near gross. Thus actual single engine service ceiling is thousands of feet higher than the published at gross weight figure (the Aztec has a chart in the POH to calculate it).

 

[hindsight2020]

Indeed, you can back-gonkulate service ceiling by backtracking the climb rate charts from the 50FPM line to the pressure or density altitude on the other side, provided they include more than one weight line. I had to do just that as part of my ATP ground eval on the semenhole. The difference above 500#s under gross can be of consequence. In the case of airplanes with large useful loads and six-banger single-engine HP such as the aztec, even more so.

 

[Todd82]

The improving economy and the fact that aerial mapping companies are moving to twins is

The bigger players in that industry have been twins for a long time. We often lament our 404's aren't getting any younger and there's nothing really equivalent being built to replace them.

Why do aerial mapping companies want twins? I’d think they’d want either singles or fixed wing drones!

You ever see the size of those high end mapping sensors? Way bigger/heavier than any civilian drone allows, and even a very tight fit in say a C206 for a pilot and a sensor operator. Couple hundred pounds easily. And you don't make money landing to fuel up a couple times a day, so if I can get 8hr endurance I'll eat a little extra fuel burn to get more data collected (i.e. revenue) in the small collection windows we have.

Now I'm talking the types of sensors you'd map cities on up with, not something a farmer is using for his fields or a construction company using for a new Walmart or highway project

 

[dans2992]

The bigger players in that industry have been twins for a long time. We often lament our 404's aren't getting any younger and there's nothing really equivalent being built to replace them.


You ever see the size of those high end mapping sensors? Way bigger/heavier than any civilian drone allows, and even a very tight fit in say a C206 for a pilot and a sensor operator. Couple hundred pounds easily. And you don't make money landing to fuel up a couple times a day, so if I can get 8hr endurance I'll eat a little extra fuel burn to get more data collected (i.e. revenue) in the small collection windows we have.

Now I'm talking the types of sensors you'd map cities on up with, not something a farmer is using for his fields or a construction company using for a new Walmart or highway project

What do these huge imagers have that requires them to be so big? What are they measuring that a smaller sensor can’t?

 

[Todd82]

What do these huge imagers have that requires them to be so big? What are they measuring that a smaller sensor can’t?

Fly higher and cover more ground per pass with wider swaths, better resolution.

You can map imagery with a photography quality DSLR, but if you want cover a whole county or something it would take you days. The sensors I'm talking about cut that to hours for the same GSD (resolution). Something like this
https://leica-geosystems.com/en-US/...-sensors/leica-ads100-airborne-digital-sensor


Especially on the lidar side sensors stay the same size or even get heavier, but point densities that used to take multiple passes over the same area can be done in one pass and to a higher accuracy with the latest generations. Or you can cover 3x the area with one pass as the sensor before it.

 

[stratobee]

I've followed the Turbo Commander market pretty religiously over the years, being a part of that world. About 2-3 years ago prices started ticking up. Back then you could get into pretty decent 690B's for about $300K. That's not they case anymore - it starts at $500K today.

 

[Red Air Rambo]

I would also point out the single engine service ceiling figure is based on the airplane being in a clean configuration, critical engine inop, prop feathered, at gross weight. This last item is critical. I have just under 1900 lbs of useful load. Whenever I am going over the Divide I keep the plane light; it is never anywhere near gross. Thus actual single engine service ceiling is thousands of feet higher than the published at gross weight figure (the Aztec has a chart in the POH to calculate it).

+1 The Cessna's chart for the P337

 

[LoneAspen]

I've followed the Turbo Commander market pretty religiously over the years, being a part of that world. About 2-3 years ago prices started ticking up. Back then you could get into pretty decent 690B's for about $300K. That's not they case anymore - it starts at $500K today.

IIRC you used to own and fly an Aerostar. Was curious if you knew how the Aerostar market was doing lately? Is it in the same vein, with prices going up?

 

[Dav8or]

I respectfully disagree.

I live on the eastern slopes of the Rockies. After owning a series of piston singles I now fly a light twin specifically because I often fly over the rocks to and from the west coast, where my wife and I grew up and still have family.

As for "grinding into the earth a hell of a lot slower" I will acknowledge the 5200 lb gross Vso of my twin (55 knots) is 9 knots higher than that of my Husky, but still a wee bit better than a Cirrus SR22 at 59 knots. But then the Cirrus has a parachute, so perhaps you have a point.

I guess my definition of "light twin" is too narrow. I thought we were talking about twins with small bore engines, like the Seminole, or Duchess, or Comanche. Your Aztec has big bore engines, no?

 

[Salty]

I guess my definition of "light twin" is too narrow. I thought we were talking about twins with small bore engines, like the Seminole, or Duchess, or Comanche. Your Aztec has big bore engines, no?

I was thinking light twin would include 310 baron, et al, but not queen air, beech 18.... but that’s just me.

 

[flyingcheesehead]

I would also point out the single engine service ceiling figure is based on the airplane being in a clean configuration, critical engine inop, prop feathered, at gross weight. This last item is critical. I have just under 1900 lbs of useful load. Whenever I am going over the Divide I keep the plane light; it is never anywhere near gross. Thus actual single engine service ceiling is thousands of feet higher than the published at gross weight figure (the Aztec has a chart in the POH to calculate it).

Indeed, you can back-gonkulate service ceiling by backtracking the climb rate charts from the 50FPM line to the pressure or density altitude on the other side, provided they include more than one weight line. I had to do just that as part of my ATP ground eval on the semenhole. The difference above 500#s under gross can be of consequence. In the case of airplanes with large useful loads and six-banger single-engine HP such as the aztec, even more so.

Excellent points.

This is also part of why any turbo twin will have a MUCH higher single-engine service ceiling than a normally aspirated one (for example, the PA30B's is 5800 feet and the PA30B Turbo is 19,000 feet). Climb is a function of excess horsepower. If you have a lower weight, more of your horsepower is "excess". With a 7100-foot single-engine absolute ceiling, the PA30 needs about 75% power on one engine to maintain altitude at gross weight.

You can calculate the climb rates for nearly any set of conditions, provided you know the single-engine absolute ceiling (or can calculate it from the charts like you said). Using that to figure out how much power you need just to stay aloft, you can adjust the weight and excess horsepower numbers to find a climb rate, or set climb rate to zero to figure out absolute ceiling.

 

[GRG55]

I guess my definition of "light twin" is too narrow. I thought we were talking about twins with small bore engines, like the Seminole, or Duchess, or Comanche. Your Aztec has big bore engines, no?

Thanks for the clarification.
I didn't make that distinction. The Aztec has IO-540s, but I tend to lump all the naturally aspirated piston twins together. The turbo-charged variety, including the pressurized Cessnas, Barons, 310s, are a step above (performance and operating costs ).

But you are correct, at the margin there may be some things I can do with my Aztec that I would avoid in an Apache or Seminole. But your original caution still has validity; one still needs to avoid overestimating the capabilities in the mountains of even the big-bore twins.

 

[stratobee]

IIRC you used to own and fly an Aerostar. Was curious if you knew how the Aerostar market was doing lately? Is it in the same vein, with prices going up?

Think they've ticked up ever so slightly, but for some reason there's still a lot of resistance in the Aerostars market. I think it's a bit of an intimidating aircraft. A lot of the ones I see sit on the market longer than you'd expect. Took me over a year to sell mine, despite constantly lowering price (but that was in 2014). Think it's a little bit easier today, but not a type that will sell as fast as a Baron. But if you can cope with the operational costs of a high end twin, then they offer the best bang for the buck in my opinion. Another thing nobody mentions is how frugal on fuel they can be, if you trade some speed. You can't beat low drag.

 

[Lantraxco]

Think they've ticked up ever so slightly, but for some reason there's still a lot of resistance in the Aerostars market. I think it's a bit of an intimidating aircraft. A lot of the ones I see sit on the market longer than you'd expect. Took me over a year to sell mine, despite constantly lowering price (but that was in 2014). Think it's a little bit easier today, but not a type that will sell as fast as a Baron. But if you can cope with the operational costs of a high end twin, then they offer the best bang for the buck in my opinion. Another thing nobody mentions is how frugal on fuel they can be, if you trade some speed. You can't beat low drag.

I think they're looked at as a bit of an orphan child, and that low drag translates to highly sensitive it would seem? I'm asking because I've never met one in person. I'm trying to bad mouth them a bit because I would love to own one someday and I'm trying to keep the prices down!

 

[stratobee]

I think they're looked at as a bit of an orphan child, and that low drag translates to highly sensitive it would seem? I'm asking because I've never met one in person. I'm trying to bad mouth them a bit because I would love to own one someday and I'm trying to keep the prices down!

Yes, but they're actually one of the best supported used aircrafts there are. There is no part you can't get from factory at a moments notice. Not always the cheapest option, but they do have great service.

 

[LoneAspen]

Is the Aerostar something that can be maintained and serviced by most (knowledgeable) shops out there? Or is it such a rare bird that you'd have a hard time finding someone good to perform maintenance on it?

I remember when I first started researching my flight training, running across Aerostars and thinking what a cool plane they were, and if I were ever lucky enough to own a plane, to maybe look at one. But I've always been wary of buying anything (especially a plane!) that could be hard to service.

 

[Ted]

Is the Aerostar something that can be maintained and serviced by most (knowledgeable) shops out there? Or is it such a rare bird that you'd have a hard time finding someone good to perform maintenance on it?

I remember when I first started researching my flight training, running across Aerostars and thinking what a cool plane they were, and if I were ever lucky enough to own a plane, to maybe look at one. But I've always been wary of buying anything (especially a plane!) that could be hard to service.

There's no monopoly on being a good mechanic, however with any specialized type like that you're going to run into some type-specific items.

For example, in the Twin Cessna world there were some specific things with them where the specialty shops were the most knowledgeable. I supplemented my "normal" A&Ps with this knowledge from my membership in the owner's group and it worked out well. I would expect you could do the same for the Aerostar.

The MU-2, I'm happier taking to a service center, but it has some really abnormal aspects to it.

 

[labbadabba]

The bigger players in that industry have been twins for a long time. We often lament our 404's aren't getting any younger and there's nothing really equivalent being built to replace them.

Tecnam P2012 (I think) New Cabin class twins for commuter and air taxi routes

 

[labbadabba]

I guess my definition of "light twin" is too narrow. I thought we were talking about twins with small bore engines, like the Seminole, or Duchess, or Comanche. Your Aztec has big bore engines, no?

The Lyc 360s and the 540s have the same bore don't they? The cylinder displacement is the same there's just two more of them...

 

[gsengle]

Tecnam P2012 (I think) New Cabin class twins for commuter and air taxi routes

Yep, and just in time. Cape Air is buying up to 100 of em.


Sent from my iPhone using Tapatalk

 

[mondtster]

The Lyc 360s and the 540s have the same bore don't they? The cylinder displacement is the same there's just two more of them...

Correct. I always laugh when people throw around the “big bore” term as if it defines something.

 

[flyingcheesehead]

Tecnam P2012 (I think) New Cabin class twins for commuter and air taxi routes

Man, every time I get excited about something Tecnam is doing, I'm disappointed. A new cabin class twin? Woohoo!

With fixed gear? Seriously? Cape Air and Tecnam decide to design a new twin from the ground up, and they basically come up with a Partenavia, which was designed 50 years ago and is still being produced.

 

[gsengle]

Man, every time I get excited about something Tecnam is doing, I'm disappointed. A new cabin class twin? Woohoo!

With fixed gear? Seriously? Cape Air and Tecnam decide to design a new twin from the ground up, and they basically come up with a Partenavia, which was designed 50 years ago and is still being produced.

135 Commuter has very specific needs.


Sent from my iPhone using Tapatalk

 

[hindsight2020]

Good enough (in my opinion) that I sold our PA32R-300 for nearly twice what I paid for our PA34-200T at the end of August. Allowed for a few upgrades that I wanted to do to the Seneca.

It probably has a lot to do with what type of aircraft you are wanting to get into. I'm noticing Barons commanding a higher price (typical for Beechcraft), but other larger twins receding slightly. Like any aircraft, if you're ready to pull the trigger when you see a deal, you can get one. They don't stick around too long.

Man it's all about timing I guess. I cannot find senecas right now for the price delta you describe. They're pretty much asking about as much as people are asking for Lances. Maybe I'm looking in the wrong place.

 

[AnthonyS1]

Man it's all about timing I guess. I cannot find senecas right now for the price delta you describe. They're pretty much asking about as much as people are asking for Lances. Maybe I'm looking in the wrong place.

I found this earlier seems like a great deal for the price. Shame it's in Europe.
http://www.aso.com/listings/spec/ViewAd.aspx?id=176628
Try finding a bonanza/saratoga with new paint/interior/ low time engine and decent avionics pack for even close to what they are asking for this Seneca! Twins really seem to be an incredible value if you can get passed the higher MX and fuel burn.

 

[Dav8or]

The Lyc 360s and the 540s have the same bore don't they? The cylinder displacement is the same there's just two more of them...

Ok. Big displacement then... All is now right with the world.

 

[Dav8or]

Correct. I always laugh when people throw around the “big bore” term as if it defines something.

It's good to laugh. It's healthy and alleviates bitterness.

 

[GRG55]

Man, every time I get excited about something Tecnam is doing, I'm disappointed. A new cabin class twin? Woohoo!

With fixed gear? Seriously? Cape Air and Tecnam decide to design a new twin from the ground up, and they basically come up with a Partenavia, which was designed 50 years ago and is still being produced.

Interesting airplane. 9 passengers (+ 2 crew), 375 hp geared, turbocharged, dual fuel (avgas/UL100) engines burning about 60 gph combined in cruise. Going to be interesting if all the advanced tech and diagnostics Lycoming has packed into this engine allows an operator to operate and maintain two of them (along with the extra prop) for less than the single PT-6 in a PC-12, Caravan or Kodiak? Viking is still producing the Twin Otter as well, but I think that thing seems to appeal more to the float plane commuter crowd in places like the Maldives, etc.

As for the airframe, it just shows that's not where the real advances in the future of passenger carrying aircraft are to be had. Lay out a set of specifications for a particular mission, set about designing it...and not surprisingly the optimized airframe solution comes out looking pretty much like its predecessor's optimized solution for the same mission.

I believe this Tecnam is metal. Everything old is new again. Imagine that.

 

[hindsight2020]

I found this earlier seems like a great deal for the price. Shame it's in Europe.
http://www.aso.com/listings/spec/ViewAd.aspx?id=176628
Try finding a bonanza/saratoga with new paint/interior/ low time engine and decent avionics pack for even close to what they are asking for this Seneca! Twins really seem to be an incredible value if you can get passed the higher MX and fuel burn.

Um, that's 125AMUs, which is exactly what Lances are going for. You just made my point for me. Great deal?

 

[flyingcheesehead]

135 Commuter has very specific needs.

Yabut, fixed gear ain't one of 'em.

Interesting airplane. 9 passengers (+ 2 crew), 375 hp geared, turbocharged, dual fuel (avgas/UL100) engines burning about 60 gph combined in cruise. Going to be interesting if all the advanced tech and diagnostics Lycoming has packed into this engine allows an operator to operate and maintain two of them (along with the extra prop) for less than the single PT-6 in a PC-12, Caravan or Kodiak? Viking is still producing the Twin Otter as well, but I think that thing seems to appeal more to the float plane commuter crowd in places like the Maldives, etc.

As for the airframe, it just shows that's not where the real advances in the future of passenger carrying aircraft are to be had. Lay out a set of specifications for a particular mission, set about designing it...and not surprisingly the optimized airframe solution comes out looking pretty much like its predecessor's optimized solution for the same mission.

I believe this Tecnam is metal. Everything old is new again. Imagine that.

I have to imagine, though, if that's where you're going to end up, that it'd be far cheaper to buy the type certificate for the AP.68TP from Vulcanair and certify an STC for the Lycoming engines rather than have to clean-sheet and certify an entirely new airframe.

It's too bad they couldn't get Cessna to get the Twin Cessna production lines rolling again.

 

[GRG55]

Yabut, fixed gear ain't one of 'em.
...

These things seem more "load haulers" than speedsters. And the Caravan, Kodiak and Twin Otter competition is also fixed gear.
Finally, I recall reading somewhere that Cape Air specified fixed.

 

[FlyingTiger]

Fixed gear for insurance purposes (and maintenance). It is a specific requirement for many 135 operators and saves them a significant amount of money.

 

[gsengle]

Fixed gear for insurance purposes (and maintenance). It is a specific requirement for many 135 operators and saves them a significant amount of money.

Speed is similar to the 402. Much cheaper to maintain the fixed gear, more rugged, fewer maintenance delays. No snow and ice in a micro switch. Speed is not a big factor in 135 Commuter, low cost, payload and cabin comfort are. Metal airframe is easier to maintain. A recip engine burns far less fuel per hour, especially at unpressurized altitudes. And turbines care about cycle counts for maintenance, pistons don’t - try costing out 12 20 min flights a day in a twin turbine airplane over time... there is a reason Cape has been around for 30 years and grown... it’s money that makes airplanes fly!


Sent from my iPhone using Tapatalk

 

[Kenny Phillips]

I saw, and want, a Diamond DA62. Fast, good load, inexpensive fuel-wise. They just need to move that decimal point one place to the left.

 

[Ted]

Tecnam P2012 (I think) New Cabin class twins for commuter and air taxi routes

Yep, and just in time. Cape Air is buying up to 100 of em.


Sent from my iPhone using Tapatalk

Man, every time I get excited about something Tecnam is doing, I'm disappointed. A new cabin class twin? Woohoo!

With fixed gear? Seriously? Cape Air and Tecnam decide to design a new twin from the ground up, and they basically come up with a Partenavia, which was designed 50 years ago and is still being produced.

Interesting airplane. 9 passengers (+ 2 crew), 375 hp geared, turbocharged, dual fuel (avgas/UL100) engines burning about 60 gph combined in cruise. Going to be interesting if all the advanced tech and diagnostics Lycoming has packed into this engine allows an operator to operate and maintain two of them (along with the extra prop) for less than the single PT-6 in a PC-12, Caravan or Kodiak? Viking is still producing the Twin Otter as well, but I think that thing seems to appeal more to the float plane commuter crowd in places like the Maldives, etc.

As for the airframe, it just shows that's not where the real advances in the future of passenger carrying aircraft are to be had. Lay out a set of specifications for a particular mission, set about designing it...and not surprisingly the optimized airframe solution comes out looking pretty much like its predecessor's optimized solution for the same mission.

I believe this Tecnam is metal. Everything old is new again. Imagine that.

Yabut, fixed gear ain't one of 'em.



I have to imagine, though, if that's where you're going to end up, that it'd be far cheaper to buy the type certificate for the AP.68TP from Vulcanair and certify an STC for the Lycoming engines rather than have to clean-sheet and certify an entirely new airframe.

It's too bad they couldn't get Cessna to get the Twin Cessna production lines rolling again.

Few thoughts on the P2012...

The whole point of it was that 402s are getting old. On those routes, speed really doesn't matter. You're not going very far, so even if you lose 10 kts, whatever. More important is downtime (and specifically none of it) and trying to reduce pilot screw-ups on piston engines that people don't know how to operate. You also want less airframe weight for more useful load. Think Cessna Caravan or Twin Otter - fixed gear. Fixed gear reduces the airframe weight and it's one less thing for the pilots to screw up.

Electronic engine control - perfect. The people to screw that up are the ones in the dynos who do the calibration, not the ones behind the yoke.

The TEO-540-C1A is direct drive, not geared. Really wouldn't want geared for that market if you could avoid it for several reasons.

Great avionics - again, make it simpler to pilots.

Personally I wouldn't want a P2012, but I can see why it fits Cape Air's wants and needs well.

 

[Ted]

Oh, also, if you're burning 30 GPH in cruise with that engine either the guys on the dyno REALLY screwed up that calibration, or you're running way too much power. 60 GPH combined? Even in the Navajo we almost never ran more than 40.

 

[LoneAspen]

I saw, and want, a Diamond DA62. Fast, good load, inexpensive fuel-wise. They just need to move that decimal point one place to the left.

I've always liked the DA42, but even if I had the money, I'm not sure I'd buy one. Diamonds don't seem to be that prevalent in the states, and that would make me concerned about parts availability, service, and support.

 

[Dav8or]

These things seem more "load haulers" than speedsters. And the Caravan, Kodiak and Twin Otter competition is also fixed gear.
Finally, I recall reading somewhere that Cape Air specified fixed.

Don't forget the Britten Norman Islander. There are still many of those in use. If the mission is to carry people, or cargo over short distances, the speed penalty for fixed gear is worth the trade off for maintenance and insurance costs.

 

[GRG55]

...The TEO-540-C1A is direct drive, not geared. Really wouldn't want geared for that market if you could avoid it for several reasons.

Thanks for correcting Ted. I picked that up in a report on the Tecnam airplane in a publication, and repeated that error.

Oh, also, if you're burning 30 GPH in cruise with that engine either the guys on the dyno REALLY screwed up that calibration, or you're running way too much power. 60 GPH combined? Even in the Navajo we almost never ran more than 40.

You would think a guy who owns a pair of IO-540s (albeit lower hp) would be more on the ball.

 

[GRG55]

Don't forget the Britten Norman Islander. There are still many of those in use. If the mission is to carry people, or cargo over short distances, the speed penalty for fixed gear is worth the trade off for maintenance and insurance costs.

I think Cape Air is replacing 4 Islanders with the Tecnams.