Avro Vulcan B Mk.4

[kerick]

I'm doing a 1/25 truck and two tires are messed up on the sides. Will definitely end up facing each other on the back duel.
This is looking awesome!

[steelpillow]

Hugely expensive 3D-printed assembly jig. Tailcone was a good friction fit, so added that too. Next job is re-profiling the upper rear fuselage and the wing mid-section leading edges.



First look at those mean and hungry intakes. Much fine filling and fettling to do there too, as well as decent splitter plates.

[kerick]

Looking very good! I really like the intakes and the LEX.

[steelpillow]

It is at this point that I discover loads more errors in the tooling. In the following pix, the nose cone and tailcone are both bulked out with plasticard. Except the tailcone was too long as well as too thin, but as I wanted to extend it anyway they saved me the trouble: every cloud has a silver lining. The leading-edge droop was too shallow, not quite "Vulcan". Sawed through from above and below to make a straight hinge, then just bent down to close the sawcut in the narrowest place, glued and backfilled. Which revealed further wobbles in the undersurface. Not visible is the trimming back of the slightly clumsy and overlarge tailfin.Tailcones have a "T" inserted, where the aft cover plate should have extended further but the kit cut it short.
Intakes and leading edges cleaned up. Aft fuselage profiled, with area-ruled waist past tailfin, and aft wing root blended in, including slight extensions around the exhausts. Exhaust silencers added, because deafening your enemy is not what is meant by "reduced signature" or semi-stealth. Derived from Concorde research - similar principle of taming the shear where airflows meet, but different in detail.
All now ready for the undercoat-filling-fettling eternal spiral towards accurate profiling and acceptable smoothness.

[PR19_Kit]

I DO like the look of that, very '3rd generation' Vulcan.   

[NARSES2]

I DO like the look of that, very '3rd generation' Vulcan.   

Indeed 

[steelpillow]

Intriguing historical precedent. The Douglas F4D Skyray flew at much the same time as the B Mk.1's leading-edge glove, presaging my B Mk.4 in a number of ways. However its aerodynamics - no camber, washout or LE droop - were still the same primitive formula as the Vulcan prototypes, and it was a typically badly-behaved "hot ship" of the period. The supersonic Convair F-102A was at much the same time receiving a conical LE droop to its equally primitive straight-edged delta and, despite being added for quite different reasons, like the Vulcan's it would prove of benefit across the entire speed range.



By contrast, SAAB's supersonic double-delta Draken, flown the previous year, was blowing everybody away. It too had the primitive profile of its US contemporaries, but the double-delta proved a lot more controllable than the US and UK offerings and SAAB never bothered to fix its - what shall we say - rather warm ship handling.
Northrop would introduce leading-edge root extensions (LERX) on the otherwise conventional F-5 Freedom Fighter a few years later, while the first true ogival delta, the BAC 221 aerodynamic test ship for Concorde, also had none of the refinements noted despite flying several years later still. Concorde itself was the first to really pull it all together, first flying in 1969.
Concorde was also kind enough to develop many improvements to the Olympus, which would be retained in the B Mk.4. France put a lot of work into the exhaust silencer, based on the fact that most of the noise comes from the viciously turbulent mixing zone between the supersonic hot exhaust and the subsonic ambient air. By widening that zone, the turbulence can be made less severe and therefore quieter. Concorde's ended up doing double-duty as an "eyelid" thrust-reverser, but the Vulcan didn't need that, so a more conventional approach could be taken. To avoid having to rework the rear support structure, the silencer was a simpler, cheaper and lighter fixing. This also made it possible to add a second stage on behind, so the plane made no more noise than the average twinjet.

[Charlie_c67]

Would that not result in a loss of the famous howl?

[steelpillow]

Would that not result in a loss of the famous howl?

The howl comes from the intake geometry, not the hot end. But yes, damping it out is part of the upgrade: critical sections of the intake ducts are perforated with tiny holes and lined with acoustic material. Fan noise is generally reduced, and the resonant howl eliminated.
When you seek even moderate stealth, howling down on your victim is not advisable.

[steelpillow]

From chit-chat elsewhere,  my concept sketch for a 1:5 scale Vulcanetta, single-seat, aft ducted fan, 22 ft (6.8 m) span, fuselage dia. 2 ft (0.6 m). Bigger fin because bigger canopy and inevitably clunkier one-thing-and-another.

Not shown: aerofoil, and especially leading-edge underside, somewhat modified since low-speed moderate AoA is higher priority that supercritical cruise.

[steelpillow]

First couple of undercoats and the much loved "Choclate triangle" or "Toblerone" is beginning to show its mojo.

Not as uber-stealthy as the F-117 which had flown a few years earlier, but it didn't have to come in out of the rain.

[Dizzyfugu]

Nice! 

[steelpillow]

Just discovered a synchronicity with the B.1B Lancer. A big makeover from the B.1A, with revised intakes and a semi-stealth paint job. Flown 1984, the year before my B Mk.4. Both types underwent a change from high- to low-altitude operations. But also some significant differences.
There has to be cool backstory in there somewhere, there are no such thing as coincidences!