Operational Performance Comparison: Viper, Beagle and Stubby

[rpgrynn]

I think it'd be easier if you try to find him the manuals for the planes you want him to compare than to toss in numbers without basis?

I don't think it's worth his time to compare using made up numbers.

You missed my point. i never said those numbers were factual,

You see Sprts said that with incomplete data he tends to be pessimistic, for example with the F-35's empty weight, most sources pin it at 29,300 lbs, however there are some reports that say the latest configuration is less than 29,100 lbs.

The incomplete data and varriation in the sources forced Sprts to become Pesemistic and use 29,400 lbs as the empty weight.

However an optimistic approach would calculate the F-35's empty weight at 29,000 lbs. the middle ground is obviously 29,200 lbs.

I was wondering if there would be changes if that weight was used.

This is just a small example, he also used 18,200 lbs for the max internal fuel of the F35.
Most sources put it at 18,498 lbs.

Let the pessimistic numbers stand. Remember, the detractors are going to toss rocks anyway. The worst case numbers
make a very compelling counterpoint to the very strange notion the aircraft can't perform.

[spazsinbad]

A bit old yet may be of interest.

DEPARTMENT OF DEFENSE STANDARD PRACTICE
GLOSSARY OF DEFINITIONS, GROUND RULES, AND MISSION PROFILES TO DEFINE AIR VEHICLE PERFORMANCE CAPABILITY
MIL-STD-3013A 9 September 2008

Source: http://www.everyspec.com/MIL-STD/MIL-ST ... 022905.PDF (1Mb)

[pron]

Okay, here is revision one. I added more detail about the loadout, drag, and fuel burn as well as correcting the typos you all have found.

Oh and guys, please keep the comments civil and relevant to the discussion. People are allowed to have differing opinions and nobody is 100% correct 100% of the time.

I just saw someone make comments to your comparison at another forum, and I would like to hear your comment on this:

"The analysis goes off the rails on slide 6 where stability is judged by the apparent position of the horizontal stabilizer, leading to a totally bogus "effective lift area". Everything else falls apart from there, not that the fankiddies at f-16.net know or care. The problem is that claimed aerospace engineer "Spurts" is confusing incidence with alpha. The H-stab is in intense downwash from the wing and is in negative alpha even with positive incidence. Find out what company he works for and don't ever fly on their airplanes."

[newmanfrigan]

[quote="pron"][quote="sprstdlyscottsmn"]Okay, here is revision one. I added more detail about the loadout, drag, and fuel burn as well as correcting the typos you all have found.

Oh and guys, please keep the comments civil and relevant to the discussion. People are allowed to have differing opinions and nobody is 100% correct 100% of the time.[/quote]

I just saw someone make comments to your comparison at another forum, and I would like to hear your comment on this:

"The analysis goes off the rails on slide 6 where stability is judged by the apparent position of the horizontal stabilizer, leading to a totally bogus "effective lift area". Everything else falls apart from there, not that the fankiddies at f-16.net know or care. The problem is that claimed aerospace engineer "Spurts" is confusing incidence with alpha. The H-stab is in intense downwash from the wing and is in negative alpha even with positive incidence. Find out what company he works for and don't ever fly on their airplanes."[/quote]

Lol. You can tell that it's "lowobservable" (ironic name), aka Bill Sweetman, who is nothing more than a Grippen fanboy with a paycheck. He couldn't analyze his way out of a paper bag. He likes to call F16.net the fankiddy forum....on Keypubs. The man has a poor grasp of irony apparently. This is classic psychological projection; F16.net is about 85% former uniform wearers. Keypubs....does it have any veterans (that aren't pro F35) at all? F16.net has an international cast of fighter pilots past, present and future, as well as maintainers, engineers etc. Does Keypubs have any (that aren't pro F35)? I've met Habu pilots on here..I've talked to Raptor pilots. We even have former Iraqi Airforce here.

Does Keypubs have even one single fighter pilot commenting (that's not pro F35)?

Bill Sweetman (lowobservable) has basically destroyed his own already very tenuous credibility over the F35. He's not an engineer, or a veteran of any kind. That's why he stays in his comfort zone in the real "Fankiddy" forum, which is of course the Keypubs. Keypubs is a Euro/Russian fanboy club where the residents comfort each other and make each other feel better about being significantly behind the US in fighter development. They shouldn't worry so much. It's not personal, it's just that the US has made a much larger investment into the critical technologies.

I can't comment on the analysis, as I'm a biologist, not an engineer, but I can say that Mr. Sweetman and the goofballs on Keypubs (Jo Asakura, JSR, MSphere) don't apply the scientific method to their analyses. There's very little of value on that site, unless you want to extrapolate hypothetical wing loadings, and ITRs.

[sprstdlyscottsmn]

Wow, my analysis jumped forums? I'm honored. Someone decides that my analysis provides enough science to question their viewpoint so they decide to attack my character? That's their problem.

My credentials are getting an Aerospace Engineering degree from Embry-Riddle Aeronautical University (#1 school in the US for an AE degree) where my studies excelled in Aerodynamics and Stability. If whoever this person is doesn't understand trim drag then that is their shortcoming. Oh, and I don't work for any aircraft manufacturer. I work for an avionics company.

I did find a mistake in part of the stability analysis where it applied to the F-15 however. When I calculated the max lift coefficient for the F-15 is was based on stall speed at a given weight. This, in effect, is the modified CLmax. The true CLmax produced by the wing would then have to be INCREASED by the trim drag effects and would put it fairly close to 1.7. The "effective lifting area" for the F-15 was independent from the rest of the analysis and only served to explain why the relatively HUGE wing of the F-15 fails to allow it to generate the kind of turn that the F-16 can generate.

As for the nature of the analysis, the data I had specifically tells the stability margin (CG with respect to the AC of the main wing, which can be geometrically found) so it was not hard to find the geometric CG and estimate the AC of the tailplane to find the moment arm from the center of mass. Incidence, and alpha, angle of the tail is a result of what force is needed by the tailplane to balance the weight of the aircraft with the lift produced by the wing and body surfaces. So while there is a downwash, that only causes the tail to increase it's incidence to reach the required alpha to get the needed lift.

A perfect example of the above was explained to me by either johnwill or Gums (they both taught me so much years ago) that at 25 degrees angle of attack the tailplanes of the F-16 are near max incidence to still provided the upward force needed to stop the plane from flipping up and going into a deep stall.

So, to anyone interested in science, take my analysis and ask doubters to use science to refute it. I have relevant education combined with real world experience of others to back up my assertions. That said, I am always willing to learn new things from people with the right credentials.

[newmanfrigan]

:

Wow, my analysis jumped forums? I'm honored. Someone decides that my analysis provides enough science to question their viewpoint so they decide to attack my character? That's their problem.



So, to anyone interested in science, take my analysis and ask doubters to use science to refute it. I have relevant education combined with real world experience of others to back up my assertions. That said, I am always willing to learn new things from people with the right credentials.

It was Sweetman. It's a compliment to be attacked by Sweetman. Those of us who are involved in the sciences are pretty wary of "journalists" and their "analyses". Even though I look at kidney cells all day, and not at EM charts, the flaws in the products of the partially-educated are usually quite glaring.

[arrow-nautics]

Okay, here is revision one. I added more detail about the loadout, drag, and fuel burn as well as correcting the typos you all have found.

Oh and guys, please keep the comments civil and relevant to the discussion. People are allowed to have differing opinions and nobody is 100% correct 100% of the time.

I belong to a FB pro-F-35 for Canada (Canadians for the F-35 Lightning II) page & I'd like your permission to post this PDF on that very page.

I await your response - EXCELLENT WORK

[XanderCrews]

So, to anyone interested in science, take my analysis and ask doubters to use science to refute it.

This^

As for Bill, Sweetman gonna Sweetman. I do find it interesting that he involves himself in the "fanboy" accusations that should be beyond a professional such as himself. There are a lot of professional aircraft and military people on forums who actually act professional (or at least their age) and calmly explain things, which is what someone like Sweetman should be acting like, but instead he is bitter jaded and biased.

[sprstdlyscottsmn]

Okay, here is revision one. I added more detail about the loadout, drag, and fuel burn as well as correcting the typos you all have found.

Oh and guys, please keep the comments civil and relevant to the discussion. People are allowed to have differing opinions and nobody is 100% correct 100% of the time.

I belong to a FB pro-F-35 for Canada (Canadians for the F-35 Lightning II) page & I'd like your permission to post this PDF on that very page.

I await your response - EXCELLENT WORK

I cannot in good conscience allow you to post those PDFs. Only because of my glaring (to me) error in the F-15Es lift coefficient in the "Stability and Lift Area" page. So I fixed it up a bit. You may of course post Revision 2. No additional changes other than clarifying the Lift Area of the F-15E and adjusting the sentence describing my choice for the CLmax value of the F-35.

As an additional note, not that I know if anyone still cares, but my Naval analysis has run into a large snag in that the data presented in the Super Hornet manual is incomplete compared to the F-15/F-16 so I need to build a model for that as well. However because of the data available it is requiring me to make a very specific model (in the wave drag area) to match listed data points.

[arrow-nautics]

Okay, here is revision one. I added more detail about the loadout, drag, and fuel burn as well as correcting the typos you all have found.

Oh and guys, please keep the comments civil and relevant to the discussion. People are allowed to have differing opinions and nobody is 100% correct 100% of the time.

I belong to a FB pro-F-35 for Canada (Canadians for the F-35 Lightning II) page & I'd like your permission to post this PDF on that very page.

I await your response - EXCELLENT WORK

I cannot in good conscience allow you to post those PDFs. Only because of my glaring (to me) error in the F-15Es lift coefficient in the "Stability and Lift Area" page. So I fixed it up a bit. You may of course post Revision 2. No additional changes other than clarifying the Lift Area of the F-15E and adjusting the sentence describing my choice for the CLmax value of the F-35.

As an additional note, not that I know if anyone still cares, but my Naval analysis has run into a large snag in that the data presented in the Super Hornet manual is incomplete compared to the F-15/F-16 so I need to build a model for that as well. However because of the data available it is requiring me to make a very specific model (in the wave drag area) to match listed data points.

I will respect your wishes I will await the revised version & I appreciate it. Tough study there Sprstdlyscottsmn. A big problem in the comparison between the SH & the CTOL is the straight/slanted hybrid wing drag penalty versus the modified delta wing drag penalty . The SH has a wing area of 500 ft² while the CTOL has an area of 460 ft². Also the SH has the (LEX's) forward surface area on each side of the cockpit. Very difficult to draw comparisons between these apples & oranges. I admire your ability to draw the distinctions. You certainly have more clout than even RAND IMO whereas you actually provide data.

[spazsinbad]

'Spurts' probably you have this NATOPS of Performance for the Super Hornet but just in case:

NATOPS FLIGHT MANUAL PERFORMANCE DATA NAVY MODEL F/A-18E/F
165533 AND UP AIRCRAFT 1 AUGUST 2006

http://info.publicintelligence.net/F18-EF-200.pdf (30Mb)

[sprstdlyscottsmn]

I do have that, thanks. The -1 for the F-15E and for the F-16 are simply FAR more comprehensive. The NATOPS for the SHornet does have the most intricate stores drag matrix I have ever seen, but other than that I find it greatly lacking.

Arrow-Nautics, I guess you missed that I posted revision 2 in that same post. I wanted to fix it up for you before I responded. You should find it at the bottom of my previous post.

[arrow-nautics]

Arrow-Nautics, I guess you missed that I posted revision 2 in that same post. I wanted to fix it up for you before I responded. You should find it at the bottom of my previous post.

I did notice that but I wasn`t sure if it was the final cut -

Is Spurts your call sign? (I know, likely a dumb question)

[hornetfinn]

Spurts, what do you think about the Mach 0.94 cruise speed for F-35B/C stated in here in relation to your excellent analysis:
http://www.f-16.net/forum/download/file.php?id=19926&mode=view

[optimist]

Spurts, what do you think about the Mach 0.94 cruise speed for F-35B/C stated in here in relation to your excellent analysis:
http://www.f-16.net/forum/download/file.php?id=19926&mode=view

AFAIK Mach 0.94 is a KPP for the 3 models with 2x2,000 a/c, 2x1,000 b, all with 2x aim-20 and 50-60% fuel . altitude unstated from memory