Blackburn P.155

[SlickDriver]

In Tony Buttler's British Secret Projects: Jet Bombers there is a list of projects by manufacturer.

In the Blackburn section P.155 says "Base burning aircraft, 1971". Does anybody have a clue as to what that means?

Thanks

 

[zen]

Could be an external ramjet, where the fusilage acts to provide both compression and expansion surfaces.

 

[TinWing]

Could be an external ramjet, where the fusilage acts to provide both compression and expansion surfaces.

Hmm.....sounds like a hypersonic project.

I wonder if the P.155 is mentioned in upcoming the 4th British Secret Projects book?

 

[Mike Pryce]

Base burning simply involved having a blunt end to the fuselage, with fuel burnt there to reduce drag, while avoiding the extra volume of a tapered rear fuselage. It is the same idea as base bleeding on an artillery shell.

HS Brough studied this idea in the late 1960s/early 1970s. There are files open at the UK National Archive that describe the work. IIRC it was horribly inefficient at low level, so was dropped.

 

[Rickshaw]

Utilised for artillery rounds. Developed by Gerald Bull for his South African produced 45 calibre G-5 155mm Howitzer. He designed a "base-bleed unit" which screwed onto the base of the artillery round and contained a gas producer which filled the drag induced turbulence behind the shell to increase the range. When coupled with a new-designed Full-Bore, pointed shell which was aerodynamically better shaped than the traditional ogive shaped shell (it had a long tapered nose which was supported by fins in the bore), it produed a startling extra 10-15km on the range of a standard 155mm gun of the day (which was only 39 calibres long).

 

[Sentinel Chicken]

Are base-bleed units used on any in-service artillery units?

(Apologies in advance for probably steering this thread away from aircraft......)

 

[Rickshaw]

Are base-bleed units used on any in-service artillery units?

(Apologies in advance for probably steering this thread away from aircraft......)

Yes. The South Africans use them. Most of the other Western artillery designers have looked at them a little askance. The Americans and NATO have concentrated on rocket boosted rounds to gain extended range and didn't take kindly to what were considered "exotic" technologies which challenged their institutionalised mindset, despite all the disadvantages with rocket boosted rounds. Apart from the SADF, I can think of a couple of others who use it. Singapore, Russia, PLA, etc.

 

[Archibald]

Utilised for artillery rounds. Developed by Gerald Bull for his South African produced 45 calibre G-5 155mm Howitzer. He designed a "base-bleed unit" which screwed onto the base of the artillery round and contained a gas producer which filled the drag induced turbulence behind the shell to increase the range. When coupled with a new-designed Full-Bore, pointed shell which was aerodynamically better shaped than the traditional ogive shaped shell (it had a long tapered nose which was supported by fins in the bore), it produed a startling extra 10-15km on the range of a standard 155mm gun of the day (which was only 39 calibres long).

This Gerard Bull, again! This guy was truly the real-world incarnation of Jules Verne heroes Nichol and Barbicane... :

 

[SlickDriver]

Israel too uses base bleed rounds, vs RAP rounds.

But I do not believe that is same thing as the base burn. I have been attempting to read about what zen provided. It is a bit over my head.

 

[Abraham Gubler]

Stumbled across this old thread searching for some Gerald Bull information (not here so I have to wait for the book to arrive from Amazon: Arms and the Man: Dr. Gerald Bull, Iraq and the Supergun by William Lowther). There are quite a few inaccurate statements in this thread about base bleed so I though to correct them.

Firstly the difference between base bleed and base burn is more than the name. Base bleed – as the name suggests – bleeds a gas to reduce tail drag that provides very little thrust. Base burn on the other hand configures a propulsive thrust system to also reduce tail drag while providing thrust.

Base bleed was not developed by Gerald Bull but by the Swedish coastal artillery in the 1960s. Bull however became very famous after he was imprisoned selling base bleed ammunition to South Africa in the 1970s. Since then base bleed has became quite common in the 1980s and 90s in 105mm and 155mm applications replacing rocket assist. Its standard issue now in most NATO model armies and was introduced for the 105mm Abbot ammunition in the 80s.

Base burn is the principle applied to the newer ~70km range South African VLAP 155mm ammunition.