F-35 and Airshows

Discuss the F-35 Lightning II
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sprstdlyscottsmn

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Unread post04 Apr 2019, 18:08

Actually all you have to say is that it was at 50AoA at the last moment of the turn and it doesn't change anything, the flight path still only changes 85deg in 3 sec. And even then there is huge margin for error as 3 sec is not exact. This turn is phenominal, there is no doubting that, but I want to be realistic about it when we are trying to count dps, which is always iffy for airshow vids.
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gta4

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Unread post05 Apr 2019, 03:12

Yes it is safe to say the peak turn rate stays somewhere between 28-40deg/sec
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Gums

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Unread post05 Apr 2019, 03:37

Salute!

Finally had time to see the coupla demos.

Makes me cry that I am 35 years older since my last Viper flight.. As Will Smith said in that Independence Day movie,

" I Gotta get me one of these things!!"

Gums wishes......
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vilters

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Unread post05 Apr 2019, 08:28

Likewise.
What makes me most jealous is the fuel quantity for a single engine.
In a clean Viper (and many others) you always have one eye on the fuel gage.
Should I spend it now? Or wait for later?

Fuel is like money. When its gone, it is gone. You can only spend it once...
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lbk000

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Unread post06 Apr 2019, 02:41

jetblast16 wrote:

@ 2:34 and somewhat beyond. Holy smokes!

What an absurd low speed turn. Definitely one of the most unnatural looking turns I've ever seen.

I love it.
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strykerxo

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Unread post06 Apr 2019, 06:05

I can not find the source, I believe it was a demo pilot that said next years demo will be a fully fleshed out demo. One of the characteristics that was emphasized was acceleration, in recent videos I see parts in the routine where the F-35 seems to be accelerating rather quickly. How would the F-35 best showcase this feature, so that the public is aware of what it is seeing?
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saberrider

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Unread post06 Apr 2019, 07:05

Gums wrote:Salute!

Finally had time to see the coupla demos.

Makes me cry that I am 35 years older since my last Viper flight.. As Will Smith said in that Independence Day movie,

" I Gotta get me one of these things!!"

Gums wishes......

The F - 35 it's moving and turning very well for the shape it has been generated for him by CFD program's. No area rules for him. But putting the slabs at far aft of the length of the jet gives him a better fulcrum to push the tail down and big wetted surfaces makes him stable in turbulence. Also clipping his wings help with the rolls. This is my opinion, if i understand how aerodynamics would work for F35. The only thing I have against it is touching screen technology. Imagine being tired and bombing and target selection it is then difficult to do. Opinions on how will work out in heat of the battle, Gums?
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marsavian

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Unread post06 Apr 2019, 07:10

The F-35 pilot can use HMD/HOTAS to select targets.
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optimist

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Unread post06 Apr 2019, 07:34

saberrider wrote:
Gums wrote:Salute!

Finally had time to see the coupla demos.

Makes me cry that I am 35 years older since my last Viper flight.. As Will Smith said in that Independence Day movie,

" I Gotta get me one of these things!!"

Gums wishes......

The F - 35 it's moving and turning very well for the shape it has been generated for him by CFD program's. No area rules for him. But putting the slabs at far aft of the length of the jet gives him a better fulcrum to push the tail down and big wetted surfaces makes him stable in turbulence. Also clipping his wings help with the rolls. This is my opinion, if i understand how aerodynamics would work for F35. The only thing I have against it is touching screen technology. Imagine being tired and bombing and target selection it is then difficult to do. Opinions on how will work out in heat of the battle, Gums?

A lot of stuff is with voice interface.
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kimjongnumbaun

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Unread post06 Apr 2019, 09:45

lbk000 wrote:
jetblast16 wrote:

@ 2:34 and somewhat beyond. Holy smokes!

What an absurd low speed turn. Definitely one of the most unnatural looking turns I've ever seen.

I love it.


Congratulations SU-57, you made it to the merge. You die anyways. :D
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steve2267

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Unread post06 Apr 2019, 13:28

saberrider wrote:The F - 35 it's moving and turning very well for the shape it has been generated for him by CFD program's. No area rules for him. But putting the slabs at far aft of the length of the jet gives him a better fulcrum to push the tail down and big wetted surfaces makes him stable in turbulence. Also clipping his wings help with the rolls. This is my opinion, if i understand how aerodynamics would work for F35. The only thing I have against it is touching screen technology. Imagine being tired and bombing and target selection it is then difficult to do. Opinions on how will work out in heat of the battle, Gums?


I strongly suspect the F-35 is highly area ruled. But it is not easily seen by the nekkid eye because it does not have the classic F-5 / F-102 coke-bottle shaped fuselage.

What do you mean by "clipped wings"? Short wingspan? To be sure, that helps with roll rate. But "clipped" implies to me a wingtip ala the F-15. I think the LO requirements probably had a lot to do with leading edge and trailing edge sweep angles. Combined with airframe length limits (set by F-35B?), probably forced the designers' hands somewhat.

All-in-all, I think the F-35 design is a masterful balancing of competing requirements.
Take an F-16, stir in A-7, dollop of F-117, gob of F-22, dash of F/A-18, sprinkle with AV-8B, stir well + bake. Whaddya get? F-35.
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spazsinbad

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Unread post06 Apr 2019, 13:53

'steven' said: "...airframe length limits (set by F-35B?)…". IIRC the F-35B was designed to specifications set for the F-35A which happened to serendipidydoodah fit under the USMC LHA F-35B length requirement for deck parking aft the island.

'serendipidydoodah' = serendipity (is there a serendipideliciously?)

GO straight past START to GENESIS: viewtopic.php?f=61&t=54424&p=415204&hilit=genesis#p415204
Genesis of the F-35 Joint Strike Fighter 2009
Paul M. Bevilaqua JOURNAL OF AIRCRAFT Vol. 46, No. 6, Nov–Dec 2009, 2009 WRIGHT BROTHERS LECTURE

“...The technical challenges involved in designing a single aircraft for all three services were met by designing three highly common, but not identical, variants of the same aircraft. The STOVL variant, which was designed first, incorporates a shaft-driven lift fan in a bay between the inlet ducts and a thrust-vectoring cruise nozzle. The [F-35B]airframe was designed to Air Force specifications, so that the conventional takeoff and landing variant was developed by removing the lift fan and vectoring nozzles from the STOVL variant and substituting a fuel tank and a conventional cruise nozzle. The Naval variant was similarly developed from the conventional variant by increasing the wing area, designing stronger landing gear, and using stronger cousin parts to handle the larger airframe loads associated with carrier takeoffs and landings. Both the STOVL and Naval variants are about 15% heavier than the conventional variant....”

Source: http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf [attached at forum URL: download/file.php?id=29919 (PDF 7.65Mb)
Last edited by spazsinbad on 06 Apr 2019, 14:02, edited 3 times in total.
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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gta4

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Unread post06 Apr 2019, 14:00

sprstdlyscottsmn wrote:Actually all you have to say is that it was at 50AoA at the last moment of the turn and it doesn't change anything, the flight path still only changes 85deg in 3 sec. And even then there is huge margin for error as 3 sec is not exact. This turn is phenominal, there is no doubting that, but I want to be realistic about it when we are trying to count dps, which is always iffy for airshow vids.


I used the drag polar of Mig-29A to estimate some order of magnitude, and here are my conclusions:

At peak ITR, the ITR dissipates at about 5deg/sec^2. So if the average turn rate in a 3 second interval is 28+deg/sec, it is safe to assume the peak ITR is more than 33deg/sec. Still very impressive though.
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gta4

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Unread post06 Apr 2019, 17:23

One more thing to notice: Olson said the pedal turn was done with the H-stabs, not rudders.

Faire Well tail-less canards :mrgreen:
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marsavian

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Unread post06 Apr 2019, 18:56

The other thing about Euro-Canards is if they could pull 50 degree of alpha and not stall in an energy starved state then their FCS would be set for them to do so. No-one in the expensive fighter game ever leaves any extra performance on the table unless it's just not stable/predictable enough to incorporate it into the final production flight software.
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