Quote from: PR19_Kit on January 03, 2024, 04:42:13 AMBut there's a heck of a lot of intake ducting forward of the gear doors on a Vigi.

Not really Kit.

Quote from: Devilfish on January 01, 2024, 10:46:54 PM

Quote from: Old Wombat on December 27, 2023, 06:12:01 AM

Quote from: NARSES2 on December 27, 2023, 06:07:49 AM

Quote from: PR19_Kit on December 26, 2023, 11:15:57 AMQuite a big BANG then....................

Yea, but I thought it would be bigger

Thank you gents 

Me, too. I expected it to be in the vicinity of a couple of kilometres/miles. Of course the EMP effect would cover a wider area.

The EMP wouldn't affect Soviet aircraft, as they tended to use valves in their equipment, rather than transistors etc

yes, but they didn't really know that at the time. When they got their hands on a MiG-25 in 1976(?) and found it was all-valve, that was something of a shock.

Quote from: SPINNERS on January 02, 2024, 11:29:00 AMThe cone at the rear of the linear bomb bay can easily be removed and whilst it leaves a gaping hole when viewed from the back it enables a third engine to be installed. The edit to do this takes about the same time that it's taken me to type this short paragraph. For this, I've had to call it a rocket engine as there is no way that I can add the extra intake area to the existing intakes or add a dorsal intake but I did give the afterburner flame a different hue to make it look different from the regular J79's. Yes, it is very, very fast!!

That looks great - nice one! 

The other reason you'd have to make it a rocket is that the centre bay isn't quite wide enough for another J-79, hence why the "real" retaliator has the centre engine raised up slighty.

Any rocket would almost certainly be burning kerosene from the main tanks with some sort of oxidiser, so the exhaust trail wouldn't be that different from the J-79s. Likely oxidisers are High-Test Peroxide (HTP) or Liquid Oxygen (LOX). LOX is very clean, whilst HTP would probably give a somewhat denser, paler exhaust trail.

High-Test Peroxide has the advantage of being a room-temperature liquid, so it needs neither pressurization nor refrigeration and can thus have oddly-shaped space-efficient tanks. It also gives very reliable ignition, since it's a mono-propellant: all you have to do is pass it over a platinum catalyst pack and it spontaneously flashes into oxygen-rich 500 deg C steam, which is enough to be a low-powered rocket in it's own right (Soyuz spacecraft use this for their attitude thrusters). Inject atomised kerosene into the steam and you get 1400-ish deg C and some serious thrust.

The downside to HTP is that very willingness to spontaneously decompose. Platinum is far from the only catalyst on a long and eccentric list that includes cotton and leather, so handling the stuff (especially in a rough-and-tumble operational environment) can get real "interesting" real quick. Also on the list are a bunch of impurities that you typically find left in the HTP from the manufacturing process, which means the tanks have to be meticulously clean and even then, you hear the occasional ominous "bloop" from a full tank. Weirdly, this means that the _purer_ this dangerous substance is, the _safer_ it is. 98% HTP (the other 2% is water) is significantly safer than 85% HTP.

The advantage to Liquid Oxygen is that it's pure, so it burns very cleanly and efficiently (it's the most efficient oxidiser by definition), and that it's a familiar substance to maintenance crews since they already handle small amounts of it that are used by cockpit environmental systems.

The huge downside to LOX is that in order to get it to be a liquid, you have to chill it to -180 deg C, which means it needs a pressurized, insulated and/or refrigerated tank, and it's inherently dangerous just due to it's temperature. Without refrigeration it also boils off, so you can't keep an aircraft fully fuelled and ready to launch for extended periods without constantly topping it up. That pressurized tank need to be a cylinder, so it won't fit space-efficiently into an irregular airframe space, and it needs a layer of insulation which also eats volume.

One problem with both options is that aviation kerosene is not the same as rocket kerosene. The latter is a special formulation called RP-1 (as opposed to JP-1, 4 etc...) which has different additives in it that are designed to dela with the higher temperatures, pressures and flow rates in a rocket engines fuel system. Rocket engines can be designed to use JP fuels, but it's pretty much guaranteed to come at some cost in efficiency.

Quote from: Dizzyfugu on January 03, 2024, 01:35:06 AM

Quote from: SPINNERS on January 03, 2024, 12:37:22 AM

Quote from: Dizzyfugu on January 03, 2024, 12:29:27 AMMakes me wonder if FAST packs from an F-15 would fit under the Vigilante's flanks/wings to extend range?

Wouldn't they foul the main undercarriage?

That could be.

They could be fitted above the fuselage similar to the F-16 or Eurofighter Typhoon (the conformal fuel tanks aren't fitted yet).

Quote from: McColm on January 03, 2024, 10:11:29 AMThey could be fitted above the fuselage similar to the F-16 or Eurofighter Typhoon (the conformal fuel tanks aren't fitted yet).

And then you're back to the RA5-C 'Humpback' shape...........................

Or as I said at the bottom of the previous page, put one under the fuselage like the one proposed for the TSR.2 in a simmilar fashion to the camera pack that was fitted to the  Vigilante

Gondor

For a clean and different look I'd still use some F-15-ish packs -  and leave a gap open for the landing gear, which would then receive a wider cover to match the wider/bulged outline. Might be complex and probably not really practical in real life, but IMHO the most elegant solution.    Got an RA-5C somewhere, with a plan, but FAST packs haven't been part of it - yet...

Quote from: Weaver on January 03, 2024, 09:52:08 AMWeirdly, this means that the _purer_ this dangerous substance is, the _safer_ it is. 98% HTP (the other 1% is water) is significantly safer than 85% HTP.

OK my brain needs to know. If this HTP is 98% HTP and 1% water, what's the other 1% ? Haven't done chemistry since I was 16.

i

Quote from: NARSES2 on January 04, 2024, 01:17:34 AM

Quote from: Weaver on January 03, 2024, 09:52:08 AMWeirdly, this means that the _purer_ this dangerous substance is, the _safer_ it is. 98% HTP (the other 1% is water) is significantly safer than 85% HTP.

OK my brain needs to know. If this HTP is 98% HTP and 1% water, what's the other 1% ? Haven't done chemistry since I was 16.

Isn't it obvious?  98% HTP, 1% Ice, 1% Slice...
 

Quote from: NARSES2 on January 04, 2024, 01:17:34 AM

Quote from: Weaver on January 03, 2024, 09:52:08 AMWeirdly, this means that the _purer_ this dangerous substance is, the _safer_ it is. 98% HTP (the other 1% is water) is significantly safer than 85% HTP.

OK my brain needs to know. If this HTP is 98% HTP and 1% water, what's the other 1% ? Haven't done chemistry since I was 16.

I'm sorely tempted to say that the other 1% is "The Problem", however the real problem is my inability to add up. 98% HTP is 2% water. How pure the water is though....

Quote from: zenrat on January 04, 2024, 02:52:34 AMIsn't it obvious?  98% HTP, 1% Ice, 1% Slice...
 

A man after my own heart 

Quote from: Weaver on January 04, 2024, 01:01:40 PMI'm sorely tempted to say that the other 1% is "The Problem", however the real problem is my inability to add up. 98% HTP is 2% water. How pure the water is though....

Thanks H 

During early 1970 a USAF review of America's air defence assets highlighted the increasing obsolescence of several aircraft including the F-101, F-102 and F-104 and whilst early F-4C Phantoms were trickling down to the ANG units McDonnell Douglas could see an opportunity to sell an optimised 'Air Defense' version of the F-4E to the USAF to swiftly and cost-effectively modernise a large proportion of Aerespace Defense Command. During this time McDonnell Douglas had studied various single-seat or stripped-down versions of the F-4 for the German Air Force but for the USAF they proposed a version of the slatted F-4E with all air-to-ground capability removed, slightly more powerful 'clean burn' J79 engines, simplified air-to-air only radar and the new solid-state AIM-7F Sparrow missile offering longer range with its two-stage rocket motor.

By this time the massive production run of the F-4 had meant that the fly-away unit cost for this simplified version of the F-4E made it one of the cheapest Phantoms ever and such was the confidence that the USAF had in McDonnell Douglas that in March 1971 they simply asked for a fixed-price quotation for 300 F-4E 'ADC' aircraft and ordered them in April 1971! First flown in June 1972 the F-4E 'ADC' were delivered in a smart and glossy 'air defense' grey scheme and entered service with  the 198th Fighter Interceptor Squadron of the Puerto Rico ANG in February 1973 replacing the F-104C's and F-104D's of that unit. Sadly, eight of the 198th's Phantoms were destroyed in a terrorist attack at Muniz ANGB in January 1981 and the unit operated several 'standard' F-4E's until 'ADC' versions could be allocated to them.

Another revised upload I'm preparing and originally posted here in 2010. Only a mild 'what if' as the USAF's Aerospace Defense Command did operate grey F-4E's with the 57th Fighter Interceptor Squadron at Keflavik, Iceland (piccie below) but I don't think any ANG units operated grey F-4E's and certainly not my dedicated 'ADC' versions.

Quote from: SPINNERS on January 05, 2024, 06:36:40 AMAnother revised upload I'm preparing and originally posted here in 2010. Only a mild 'what if' as the USAF's Aerospace Defense Command did operate grey F-4E's with the 57th Fighter Interceptor Squadron at Keflavik, Iceland (piccie below) but I don't think any ANG units operated grey F-4E's and certainly not my dedicated 'ADC' versions.

When I was there 30 years ago, they'd repainted the static F-4 in front of HQAFI into the "standard" (at the time) Hill One scheme.

Northrop/McDonnell Douglas F-23E 'Karish' - 119 Squadron, Israeli Air Force, 2011

With the success of the McDonnell Douglas F-4 Phantom and F-15 Eagle in Heyl HaAvir service the Israeli's were hoping that the Northrop/McDonnell Douglas F-23A 'Black Widow' would win the USAF's ATF competition to continue their successful relationship with the McDonnell Douglas team at St. Louis but unfortunately Lockheed Martin's victory in the ATF competition looked like bringing an end to a long and enduring partnership.

However in a brave move, in May 1991 the Northrop/McDonnell Douglas team secured permission from Congress to actively market the F-23 to (State Department) 'approved' nations and offered a single-seat multi-role version called the F-23E (Export) to Germany, Japan, Israel and the UK. With Germany looking for any excuse to get out of the Eurofighter consortium and facing high reunification costs they persuaded the UK to team up in a combined purchase of 200 F-23E's. In return, this led to the German and UK Governments persuading Northrop/McDonnell Douglas to make BAe and MBB prime sub-contractors for any further export sales.

However, with only 200 F-23E's on order Northrop/McDonnell Douglas were not convinced that it was enough to start a viable programme but the breakthrough came in January 1994 when the USAF agreed to purchase 100 F-23A's for PACAF (the air component of United States Pacific Command) and this move finally saw Japan and Israel also join the programme with 100 F-23E's each.







One that I originally did back in 2009 but it's a bit more refined this time and with lo-viz insignia including the 119 'The Bat' Squadron tail marking also in lo-viz. I'm not really into the 'glass cockpit' era but I do like the shape of the YF-23 and this 3D model is an absolute cracker.