Author Topic: RW materials question for the Whiffverse:  (Read 6971 times)

Offline elmayerle

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Re: RW materials question for the Whiffverse:
« Reply #30 on: January 05, 2014, 02:40:33 PM »
The conformal pallet could pick up the pylon attach points and be just as jettisonable.  I'd rather go with a conformal pallet to keep the interference drag down.  Too, the pallet allows you to better spread out and arrange all the components and tankage.

Offline Daryl J.

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Re: RW materials question for the Whiffverse:
« Reply #31 on: January 05, 2014, 04:42:24 PM »
Would said pallet allow for the doors in the Phantom's aft belly?
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Offline Daryl J.

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Re: RW materials question for the Whiffverse:
« Reply #32 on: January 05, 2014, 04:46:08 PM »
Secondarily, what would be a maximum velocity for the factory stock alloys?   Mach 2.4-.5?
« Last Edit: January 05, 2014, 04:51:40 PM by Daryl J. »
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Offline PR19_Kit

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Re: RW materials question for the Whiffverse:
« Reply #33 on: January 05, 2014, 10:06:54 PM »
The three IDF F-4E(S)s, which grew out of the F-4X project, retained their Sparrow bays as they were build from F-4E airframes IIRC.
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Kit

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Offline GTX_Admin

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Re: RW materials question for the Whiffverse:
« Reply #34 on: January 06, 2014, 02:06:16 AM »
Secondarily, what would be a maximum velocity for the factory stock alloys?   Mach 2.4-.5?

Apart from some key areas such as radome, windscreen, engine faces,,,and paint ;), I think you will find that most of the materials would last until at least 2.7/2.8 unless of course you were doing extended runs at high speed and thus temperature.  That is without the suggested ablative coatings though since adding these would alleviate the problem regardless of the materials below.
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Offline elmayerle

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Re: RW materials question for the Whiffverse:
« Reply #35 on: January 06, 2014, 08:16:08 AM »
Would said pallet allow for the doors in the Phantom's aft belly?
It would probably need to be designed around them for routine servicing but major maintenance would likely require removing the pallet.

Offline elmayerle

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Re: RW materials question for the Whiffverse:
« Reply #36 on: January 06, 2014, 08:19:50 AM »
Secondarily, what would be a maximum velocity for the factory stock alloys?   Mach 2.4-.5?
ISTR that the Phantom had a max. limit of Mach 2.8, though that generally required component replacement afterwards.  For your purposes, I could see the use of ablative material and possibly a special engine build allowing this somewhat more regularly.

Offline tankmodeler

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Re: RW materials question for the Whiffverse:
« Reply #37 on: January 06, 2014, 10:53:22 AM »
I could see the use of ablative material and possibly a special engine build allowing this somewhat more regularly.
Ablatives have the disadvantage that as they ablate they create a rough surface, increasing drag.

Mach 2.7 in a Phantom might be the "do not exceed" speed, but it's not somethiing that could be maintained for more than a second or two, much less minutes. And probably not obtained in level flight. You probably needed to be in a serious dive, with a tailwind, to get near it.  :)

Offline Daryl J.

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Re: RW materials question for the Whiffverse:
« Reply #38 on: January 06, 2014, 12:24:08 PM »
I'll have to ask Bill, my co-Dr. at work how fast they got their F-4J to.   High altitude, shallow dive, full AB.  1750 is what comes to mind but will ask again.   
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Offline Daryl J.

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Re: RW materials question for the Whiffverse:
« Reply #39 on: January 06, 2014, 12:31:23 PM »
Same questions apply to the Starfighter.   And presumably the same answers. 

I just prefer the Phantom.  ;D
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Re: RW materials question for the Whiffverse:
« Reply #40 on: January 06, 2014, 02:38:46 PM »
Mach 2.7 in a Phantom might be the "do not exceed" speed, but it's not somethiing that could be maintained for more than a second or two, much less minutes. And probably not obtained in level flight. You probably needed to be in a serious dive, with a tailwind, to get near it.  :)

That's where the suggested rocket helps...
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Offline tankmodeler

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Re: RW materials question for the Whiffverse:
« Reply #41 on: January 07, 2014, 12:08:25 PM »
That's where the suggested rocket helps...
Generally, when you exceed the "do not exceed" speed, the wings fall off immediately, they don't take the time to melt. :)  DNE speeds are almost always structural limits.

Paul

Offline elmayerle

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Re: RW materials question for the Whiffverse:
« Reply #42 on: January 07, 2014, 09:28:03 PM »
Not necessarily wings, the DNE speed for the XF8U-3 was, so I've read, set by where the canopy started melting.  So DNE values are set by reality, the Mach .82 DNE for the Learjet is set by where the wing is almost at a Mach tuck condition where the flow over the wing goes supersonic and generates a severe nose-down pitching moment.  There were some cases in the early 1980's where Learjets made big smoking holes from 45,000 ft. and it was found that the pilots had prevailed on the maintainers to put in an over-ride on the Mach limit function on the autopilot to allow them to go faster; unfortunately, this got them into this range.