World's biggest jet engine about to get bigger, quieter ..and make more contrails

a reply to: luxordelphi

Oh for heaven's sake! Read the article before you start typing.

Pay close attention now...

You said and I quote...

They never achieved cruise because the research craft (Falcon) wasn't able to follow.

You do understand that the Falcon has a max ceiling at 41000 ft, and how did they get the shot of both planes side by side if they only went up then down?

Also you have pretty much contradicted yourself...

Therefore, the B707 and A340 flew at reduced power to let the Falcon follow at constant distance

Also look at figure 2 and what does it say...This is what is said..

Fig. 2 Airbus A340 with contrails (left) and the Boeing B707 without contrails (right) taken from the Falcon research aircraft at about  ight level
333 hft at 7:28 UTC, 15 Sept. 1999 (photographs: U. Schumann and R. Welser, DLR).

Now we have this from Figure 3...

Fig. 3 Airbus A340 with contrails (left) and the Boeing B707 without contrails (right) taken from the Falcon research aircraft at about  ight level
344 hft at 7:40 UTC, 15 Sept. 1999.

elib.dlr.de...

So then what was it you said...oh that's right...

They never achieved cruise because the research craft (Falcon) wasn't able to follow.

Again do you pay attention to what you say before you post comments that are completely wrong?

And I know what the capabilities of the Falcon 20 because I have a thread that discusses this very plane.

www.abovetopsecret.com...

a reply to: luxordelphi

Maybe you can help with the relevance of your "article". I know you care little about the thread titles and all, but WTF does your kids paper have to do with, well,...anything?


It seems all you need to do to find RH is look at some weather balloon data.

These observations include vertical profiles of temperature, humidity, wind speed and direction, atmospheric pressure, and geopotential height.

www.ncdc.noaa.gov...

And for some strange reason, I don't see mention of any kids. Go figure.

originally posted by: luxordelphi
a reply to: mrthumpy

Can you propose another reason for contrail persistence?

Yes I can: "...a tragically altered atmosphere." That's a quote from Carnicom.

The RH Deception

Did you have to donate anything to get that info, or did he throw you a bone for free?

a reply to: network dude

And for some strange reason, I don't see mention of any kids. Go figure.

Does that surprise you?

It shouldn't.

a reply to: luxordelphi

Yes I can: "...a tragically altered atmosphere." That's a quote from Carnicom.

Please tell me that your not using something from Cliff Carnicom as a credible source?

originally posted by: luxordelphi
a reply to: mrthumpy

Can you propose another reason for contrail persistence?

Yes I can

But only if you make up your own physics

originally posted by: luxordelphi
a reply to: mrthumpy

Can you propose another reason for contrail persistence?

Yes I can: "...a tragically altered atmosphere." That's a quote from Carnicom.

The RH Deception

Perhaps you'd like another try at answering my question since that link doesn't

Can you propose another reason for contrail persistence?

originally posted by: tsurfer2000h
a reply to: luxordelphi

And I know what the capabilities of the Falcon 20 because I have a thread that discusses this very plane.

www.abovetopsecret.com...

And which model of the -20 did you learn about from posting a thread? The original 20 with the Pratt JT12As? or the20Cs converted to Ds with the GE CF700 engines? Or the E or the heavier F? Or maybe the H. Or the Dash5 models with the big Garrett engines? I looked at your thread and didn't see any discussion of the weight/temperature climb profile charts or step-climb procedures.
I wish I could have gotten to know the capabilities of the 20 and all of its variants by merely posting the start of a thread. Instead, I had to go to the Flight Safety facility at Teterboro to get initial flight and simulator training for the FAA type rating and then "differences training" for our 20 which was the re-engined -731 variant with the Allied Signal engines. Yeah, sure, it will go to 42,000 feet, but it sure as hell won't do that at 28000 pounds. You need to stop in the low to mid 30s and burn off some fuel first. The only small jet I ever flew that could go straight from a MTOW takeoff to service ceiling without stepping up was the Gulfstream (both III and V.)

a reply to: F4guy

Which is irrelevant because none of that came into play. They DID stop in the 30s, which is where the pictures and experiment took place. Pointing out the capabilities of the Falcon was merely to show that the aircraft was capable of staying up with both commercial planes, contrary to what was stated.

originally posted by: Zaphod58
a reply to: F4guy

Which is irrelevant because none of that came into play. They DID stop in the 30s, which is where the pictures and experiment took place. Pointing out the capabilities of the Falcon was merely to show that the aircraft was capable of staying up with both commercial planes, contrary to what was stated.

Your post shows where getting your expertise from YouTube or Wikipedia has shortcomings. We can ignore for a moment the differences in rate of climb and weight based climb profiles. One peculiarity of the Falcon 20 was that it slowed down as you went up. Mmo/Vne was highest at 20,000 feet with a speed of 465 knots (534 mph). At 40,000 feet, it slowed to 405 knots.It didn't have a super critical wing so increasing alpha at altitude generated tons of induced drag.The 707 was fastest at 28,000 feet at 495 knots. The A340 is even better at altitude with 490 knots at 35,000 feet. So real life experience (about 10,000 hours of it) demonstrates that in the mid 30s, both airliners are going to run away from a Falcon 20.

a reply to: F4guy

And again, irrelevant, because it didn't have to keep up with them for thousands of miles. The experiment was only designed for a short distance to see if there was a difference in contrail performance with the different engines. If there was, then it would show up quickly, and they wouldn't have to keep up for long.

a reply to: F4guy

I wish I could have gotten to know the capabilities of the 20 and all of its variants by merely posting the start of a thread. Instead, I had to go to the Flight Safety facility at Teterboro to get initial flight and simulator training for the FAA type rating and then "differences training" for our 20 which was the re-engined -731 variant with the Allied Signal engines. Yeah, sure, it will go to 42,000 feet, but it sure as hell won't do that at 28000 pounds. You need to stop in the low to mid 30s and burn off some fuel first. The only small jet I ever flew that could go straight from a MTOW takeoff to service ceiling without stepping up was the Gulfstream (both III and V.)

You can...

www.dlr.de.../129

And you can find the capabilities on their website...link above.

But maybe this will help...

Technical data

Falcon 20E, Kennung D-CMET

Length: 17.2 metres (18 metres including nose boom)
Height: 5.32 metres
Wingspan: 16.3 metres
Cabin length: 5.5 metres
Cabin width: 1.7 metres
Cabin height: 1.62 metres
Seats: 10 (For DLR research purposes: three seats for crew members and three scientists or engineers, depending on instrumentation)
Empty weight: 7.53 tonnes
Total weight: maximum 13.2 tonnes
Engines: two Garrett Turbojet TFE 731-5BR-2C
Thrust: 2x20 000 newton (no reverse thrust)
Range: approximately 3 700 kilometres
Flight altitude: maximum 12.8 kilometres (42 000 feet)
Speed: maximum 917 kilometres per hour (Mach 0.865)
Endurance: 5h30min (depending on payload)
Fuel tank capacity: 5007 litres (4.006 tonnes)
Original use: Business jet and military use
DLR flight facility: Oberpfaffenhofen

www.dlr.de.../129

a reply to: tsurfer2000h

I'm not sure I would trust someone who describes the engines as "two Garrett Turbojet TFE 731-5BR-2C " engines. They are geared turbofans and there is a huge difference. And the performance parameters that really count for this type of application would include the details of climb performance at 20,000 feet PA at 18,000 pounds at ISA plus 10 degrees, for example.

a reply to: F4guy

The technical difference between turbojets and turbofans are semantics these days - there hasn't been a civilian turbojet put on an airliner for decades.

And none of the Falcon's performance characteristics matter a damn to the point of the thread anyway!

originally posted by: Aloysius the Gaul
a reply to: F4guy

The technical difference between turbojets and turbofans are semantics these days - there hasn't been a civilian turbojet put on an airliner for decades.

And none of the Falcon's performance characteristics matter a damn to the point of the thread anyway!

As someone who has several thousand hours flying both the turbojets and fans, I can tell you it is much more than semantics. There are still plenty of CF700 turbjet powered 20s out there, particularly out of the US in places without our mandated Stage III requirements.It costs several million dollars to reengine the Falcon from the GEs to the Garretts And some people were discounting an experiment involving a 707, an A340 and a Dassault chase plane because they couldn't believe that the 20 couldn't keep up. Simply put, above 20,000 feet it couldn't.

a reply to: F4guy

And it didn't have to for longer than a few minutes. It had to stay in camera and sensor range long enough to perform the experiment, which it could and did. It wasn't trying to keep up with them across a long distance.

originally posted by: Zaphod58
a reply to: F4guy

And it didn't have to for longer than a few minutes. It had to stay in camera and sensor range long enough to perform the experiment, which it could and did. It wasn't trying to keep up with them across a long distance.

I guess if one is willing to accept Navy formation parameters (e. g. "same direction - same day) 26 miles is close enough. Of course, the atmospheric sensors in the chase plane would be taking measurements in a different county.

a reply to: F4guy

All they were sampling was the humidity of the area they were flying through. Since there were contrails formed, then the readings taken by the sensors would be relevant, and applicable. The primary point of the experiment was to show that under the same conditions, at the same altitude, a high bypass turbofan would produce contrails where a low bypass turbofan wouldn't, which is exactly what they did.