Once in a lifetime sight

DavidWhite

DavidWhite

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A Duke, with the engines running and MOVING under its OWN power! Then, a few minutes later the unthinkable happened. It tookoff! I was waiting for the tail to fall off and the engines with rusted camshafts to stop working.

(explanation http://www.xtranormal.com/watch/7798817/dukes-explained)
 
My bird, this winter, has rivalled Duke.

When I'm driving back form NYC at 0100 trying to not fall asleep betweeen CMI and Peoria, I know the airplane has won.

NONTHELESS, until the next breakdown, I have a fully operational machine again! :)
 
bbchien said:
My bird, this winter, has rivalled Duke.

When I'm driving back form NYC at 0100 trying to not fall asleep betweeen CMI and Peoria, I know the airplane has won.

NONTHELESS, until the next breakdown, I have a fully operational machine again! :)
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I know how you feel Dr. Bruce. When I was getting my IR with Jesse my airplane exceeded the Duke - I was there for a month and the plane flew on 11 days.
 
N747JB said:
Did you call CNN? :D I flew in one once, took more runway than any other GA airplane I have ever flown in.:hairraise:
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Likely because the owner knew what he was doing and only used the power required. There are tricks to running them to minimize maint. If you fly them to marketing department numbers the TIO 541s are horrible engines that can't get rid of their heat well enough. The TIGO 541 from the P Navajo can actually last longer if you run them max at 385hp they make without the extra RPM. There is one guy I know with a P-Navajo that does well with it, but he flies low power settings always.
 
Such a shame, I think the Duke is a beautiful airplane. Too bad about the mx expense issues. Also doesn't seem to have astounding performance.

Hope you guys had fun at Fred.
 
Let'sgoflying! said:
Such a shame, I think the Duke is a beautiful airplane. Too bad about the mx expense issues. Also doesn't seem to have astounding performance.

Hope you guys had fun at Fred.
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The three are intertwined.The beauty sells the plane. The Duke is a natural presurized step in the Beech line. That pressurization carries with it a weight and fuel penalty that they were not expecting. Since the plane was already slow, the owners pushed the power up to high power for cruise. At pressurized altitudes the air isn't dense enough to get rid of the heat so they have to dump a ton of fuel into them to keep the CHT down. This ends up wasting tons of fuel, washing out the rings and causing cylinder and valve problems. I taught my buddy how by just giving up 12 kts, he could cruise 190 TAS @ 16,000 on 27gph and use the red handles back to reduce CHT instead of forward. After that the plane was fine and looked every bit as cool rolling onto the ramp, it just got there a few minutes later. That was until it got bent in clear air turbulence.
 
Henning said:
I'd own one if it came with fresh engines and props.
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Isn't there a STC out there for PT6A's on them? It'd be a mini Queen Air that still looks sexy. Gets rid of a lot of issues minus the tail jokes.
 
bigblockz8 said:
Isn't there a STC out there for PT6A's on them? It'd be a mini Queen Air that still looks sexy. Gets rid of a lot of issues minus the tail jokes.
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The Royal Turbine IIRC from Rocket Engineering. PT-6 powered Duke for around $900k.
 
DavidWhite said:
A Duke, with the engines running and MOVING under its OWN power! Then, a few minutes later the unthinkable happened. It tookoff! I was waiting for the tail to fall off and the engines with rusted camshafts to stop working.

(explanation http://www.xtranormal.com/watch/7798817/dukes-explained)
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I've seen that happen a few times, quite scarily. With the ~2900 RPM takeoff and 2500 RPM cruise, those engines are real screamers... for the 5 minutes they can run. The 310 I fly does similar with the IO-520-Es, 2850 RPM takeoff and 2300-2500 RPM cruise (I do 2300). Too high revs.

bbchien said:
My bird, this winter, has rivalled Duke.

When I'm driving back form NYC at 0100 trying to not fall asleep betweeen CMI and Peoria, I know the airplane has won.

NONTHELESS, until the next breakdown, I have a fully operational machine again! :)
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:rofl:

Sorry to hear about your woes. I feel your pain, my friend.
 
I'd look cool in a duke.
 
flyingron said:
I'd look cool in a duke sitting in it and making airplane noises.
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FTFY. ;)

I somewhat questioned the point of the Duke. A bit more room than a 58P with less speed, less reliability, and higher costs. It was tremendously underpowered, and should have had TIGO-541s or the 435 HP GTSIO-520s used in the Commander 685. Geared engines would have been nice for sure given the high RPM required in cruise with the straight engines.
 
Also worth pointing out there are a lot of things technically inaccurate about that video. The mo-rons at Lick-coming didn't put the intake through the sump. The Duke has a top-mount intake. Even so, my Aztec runs LOP quite nicely with the intake through the sump.

As George Braly said regarding the Duke (may not get the quote word for word) "It can be run LOP, but there are issues..."
 
Ted DuPuis said:
FTFY. ;)

I somewhat questioned the point of the Duke. A bit more room than a 58P with less speed, less reliability, and higher costs. It was tremendously underpowered, and should have had TIGO-541s or the 435 HP GTSIO-520s used in the Commander 685. Geared engines would have been nice for sure given the high RPM required in cruise with the straight engines.
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Plus it takes those big paddle props that are expensive as all hell. That engine ROCKS on a 56TC Baron though. You could peg the VSI on a sea level T/O.
 
Henning said:
Plus it takes those big paddle props that are expensive as all hell. That engine ROCKS on a 56TC Baron though. You could peg the VSI on a sea level T/O.
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The 56TC is on my list of planes I want to fly. I always thought that the 56TC/Duke engines would have turned the P-Baron into piston with turbine performance, and the pressurization to make it worthwhile to go up high.

Now if only I could throw some GTSIO-520s on the 310... :D
 
Looked well rested after visiting the Hanger Hotel in Fredricksburg TX.
 
Possibly stupid question. Why would installing 2 PT6s on a Duke decrease the service ceiling 2,000'?
 
Ted DuPuis said:
The 56TC is on my list of planes I want to fly.
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Get in naked, you'll grin like a MF as long as you have fuel. It'll do torsional aerobatics out the ying yang. There's nothing really that need exceed 3G, and none of it is difficult. Flying like that 50 gallons doesn't go a long way though ;)

It flies like a 55 but faster (I cruised it 210, going faster wastes fuel, at 210 I burned 28gph, it'll do 250), the big difference is when you hit the throttles, push em forward across 2 seconds and release brakes at 1800, got me about the best kick :D . Then the rotation, if you pick up at red line level retracting in GE until blue line with with a clean plane you can establish one impressive rate of climb and an awesome angle of climb demonstration. It still has an amicable cruise climb with a ton of fuel onboard.
 
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bartmc said:
Possibly stupid question. Why would installing 2 PT6s on a Duke decrease the service ceiling 2,000'?
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Certified service ceilings may not have to do with what the airframe is capable of so much as various components simply being certified for a particular altitude.

Example: On one certification project, we set the service ceiling at 25,000 ft because to certify above it would have required additional tests on the electronics that we didn't want to do. And, well, we really didn't figure anyone would want to fly this aircraft any higher.

My guess is when they did the conversion, to certify higher than what they did (I'm not sure what altitude they certified it to) would have been more effort than they had the time and money to spend.
 
bartmc said:
Possibly stupid question. Why would installing 2 PT6s on a Duke decrease the service ceiling 2,000'?
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Or, the PT-6 might have just run out of enough power at that altitude.

They do run out of power as you climb. That is why they are flat rated.
 
Ted DuPuis said:
Certified service ceilings may not have to do with what the airframe is capable of so much as various components simply being certified for a particular altitude.

Example: On one certification project, we set the service ceiling at 25,000 ft because to certify above it would have required additional tests on the electronics that we didn't want to do. And, well, we really didn't figure anyone would want to fly this aircraft any higher.

My guess is when they did the conversion, to certify higher than what they did (I'm not sure what altitude they certified it to) would have been more effort than they had the time and money to spend.
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According to wikipedia, the Duke is certified to 30,000' if you do the Rocket Engineering STC to install a couple of PT6s it goes to 28,000'
 
bartmc said:
Possibly stupid question. Why would installing 2 PT6s on a Duke decrease the service ceiling 2,000'?
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I'm not a big turbine guy, so don't take this as gospel, I would modify it with better info. It's a flat rated engine which I think means it's fuel restricted; basically it gets to an altitude where it gets 'too LOP' to support combustion. I haven't played with turbines enough to know the exact mechanism for sure, but that's how I would go about it.
 
bartmc said:
According to wikipedia, the Duke is certified to 30,000' if you do the Rocket Engineering STC to install a couple of PT6s it goes to 28,000'
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Keep in mind that when the Duke was certified, the requirements were significantly less stringent. Beechcraft was probably trying to get it higher to get some better performance numbers. I've never heard of anyone actually flying a Duke at FL300.

To make matters more interesting, RVSM airspace was added. This doesn't impact already-certified aircraft, but it does mean that there's not much sense in certifying an aircraft to anything higher than FL280 that's not RVSM equipped. These factors combined might impact the decision to certify it to a lower altitude.

Even with PT-6s, I doubt you'd have any good reason to go above FL270 in a Duke. In the Cheyenne, the highest we've gone is FL250 when we were lightweight, with a nice tailwind, going non-stop a long ways. The theory of going really high in these aircraft is nice, but the operational realities may be different.
 
Sorry to revive this thread. I can't get "Dukes explained" to open. Is this tube on another site?

Thanks
 
bbchien said:
My bird, this winter, has rivalled Duke.

When I'm driving back form NYC at 0100 trying to not fall asleep betweeen CMI and Peoria, I know the airplane has won.

NONTHELESS, until the next breakdown, I have a fully operational machine again! :)
Click to expand...

More systems, more to break. And you guys laugh at me flying my little Cherokee. Then again, I'd be driving back from New York because the wx always sucks. Actually, I wouldn't be driving back from NY. I hate NY.
 
I saw one moving again today.

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It was thoroughly terrifying. I was worried that the engines were going to come apart and pieces were going to hit my airplane.
 
Flat rated means the opposite. The engine is artificially limited (by engine gage markings) to much lower HP than it will actually produce at SL, but will then produce more power at altitude than a lower-powered engine without the flat rate limitation.

Without seeing the POH, I'd guess that the short wing ran out of lift at the lower altitude, but the flat-rate engines were able to produce sufficient speed and economy that they didn't need attain the same service ceiling to achieve desired performance. Cabin altitude considerations might also have been a factor, since IIRC the PSI differential for Duke cabin wasn't all that spiffy.
Henning said:
I'm not a big turbine guy, so don't take this as gospel, I would modify it with better info. It's a flat rated engine which I think means it's fuel restricted; basically it gets to an altitude where it gets 'too LOP' to support combustion. I haven't played with turbines enough to know the exact mechanism for sure, but that's how I would go about it.
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The Duke is very attractive, but it really was poorly designed.

Takeoff power is 2900 RPM, cruise power is 2500 RPM (noisy), it burns a lot of fuel (~50 GPH), it goes really slow for that fuel burn (~190 KTAS), and it only holds 6 people, not particularly comfortably. Plus parts are outrageous.

I thought they should have put in GTSIO-520s or TIGO-541s instead of the TIO-541s. Either one would have been significantly quieter, and had better altitude performance (and probably better performance everywhere).
 
wabower said:
Flat rated means the opposite. The engine is artificially limited (by engine gage markings) to much lower HP than it will actually produce at SL, but will then produce more power at altitude than a lower-powered engine without the flat rate limitation.

Without seeing the POH, I'd guess that the short wing ran out of lift at the lower altitude, but the flat-rate engines were able to produce sufficient speed and economy that they didn't need attain the same service ceiling to achieve desired performance. Cabin altitude considerations might also have been a factor, since IIRC the PSI differential for Duke cabin wasn't all that spiffy.
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??? How is that different from fuel restricted? If you can't push the throttles all the way forward because you already hit a limitation, I consider that fuel restricted.
 
You can push them forward and generate significantly more HP if you want, and the engine won't know or care since it is capable of doing so without breaking a sweat. The limitation is purely based on the placement of the red lines on the torque and temp gages, and certification and performance are based thereon. The pilot is on Scout's honor to comply. And it's not a fuel restriction anyway, it's an air restriction.

Henning said:
??? How is that different from fuel restricted? If you can't push the throttles all the way forward because you already hit a limitation, I consider that fuel restricted.
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wabower said:
You can push them forward and generate significantly more HP if you want, and the engine won't know or care since it is capable of doing so without breaking a sweat. The limitation is purely based on the placement of the red lines on the torque and temp gages, and certification and performance are based thereon. The pilot is on Scout's honor to comply. And it's not a fuel restriction anyway, it's an air restriction.
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The Power lever controls airflow? I never saw a throttle plate on a turbine. I thought the power lever controlled fuel flow and increased airflow was the reaction, hence the hot start issue AME requirements for minimum airflow before advancing the fuel to start.
 
It's the opposite, but the pilot moves the condition lever rather than the power lever. Without airflow nothing happens no matter where you put the lever. 80 PSI (on P&W) is required to open the fuel valve for start.

Henning said:
The Power lever controls airflow? I never saw a throttle plate on a turbine. I thought the power lever controlled fuel flow and increased airflow was the reaction, hence the hot start issue AME requirements for minimum airflow before advancing the fuel to start.
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