BAe HOTOL

[steelpillow]

The December 1986 issue (No.12) of Spaceflight News, pages 12-15, carried an article of mine titled "Composite HOTOL", suggesting that HOTOL should be launched from a carrier plane. Here is my original three-view from which the drawings accompanying the article were enlarged and coloured in:

Much to my surprise, the HOTOL Project and Technical Manager, B.R.A. Burns, wrote a letter in reply, which was published in the March 1987 issue (No.25), Page 31. He questioned in particular the high capital cost of developing a special-purpose carrier aircraft.

At about the same time Bernard Carr, a professional model maker, put forward the idea of modifying a Boeing 747 for this purpose. I still have copies of some of his model photographs and correspondence. A letter to him from the British National Space Centre and dated 19 February 1987 comments, "Your idea of launching HOTOL from an existing aircraft is not new and indeed is already being examined as one of a range of options..." and, "... there are some potential advantages in the subsonic aircraft option ... but it is thought that these may be offset by greater expense. However it is too early yet to come to any conclusions."

Then, B.Ae's news release 124/90 of 5 September 1990 announced a six-month joint study with the Soviet Ministry of Aviation Industry on "Interim HOTOL" (their quotes) which would be launched at an altitude of 9000 metres from the Soviet Antonov AN-225 super transport aircraft.

 

[hesham]

Amazing drawing Steelpillow,many thanks.

 

[Michel Van]

That "Composite HOTOL" is so Thunderbirds...

 

[flateric]

HOTOL models at Farnborough and - now - at BIS HQ
Mriya-HOTOL models, showing evolution of early concept configurations (later one is from BIS collection, too)

 

[flateric]

Interim HOTOL & Mriya (www.buran.ru)

 

[flateric]

...

 

[flateric]

...

 

[Michel Van]

what for payload is that on Hotol model ?


that on lower right is spacelab hardware, but what is the other ?

 

[martinbayer]

The December 1986 issue (No.12) of Spaceflight News, pages 12-15, carried an article of mine titled "Composite HOTOL", suggesting that HOTOL should be launched from a carrier plane. Here is my original three-view from which the drawings accompanying the article were enlarged and coloured in:

Much to my surprise, the HOTOL Project and Technical Manager, B.R.A. Burns, wrote a letter in reply, which was published in the March 1987 issue (No.25), Page 31. He questioned in particular the high capital cost of developing a special-purpose carrier aircraft.

At about the same time Bernard Carr, a professional model maker, put forward the idea of modifying a Boeing 747 for this purpose. I still have copies of some of his model photographs and correspondence. A letter to him from the British National Space Centre and dated 19 February 1987 comments, "Your idea of launching HOTOL from an existing aircraft is not new and indeed is already being examined as one of a range of options..." and, "... there are some potential advantages in the subsonic aircraft option ... but it is thought that these may be offset by greater expense. However it is too early yet to come to any conclusions."

Then, B.Ae's news release 124/90 of 5 September 1990 announced a six-month joint study with the Soviet Ministry of Aviation Industry on "Interim HOTOL" (their quotes) which would be launched at an altitude of 9000 metres from the Soviet Antonov AN-225 super transport aircraft.

Compare to this design: http://www.secretprojects.co.uk/forum/index.php?topic=23384.0

Martin

 

[steelpillow]

The December 1986 issue (No.12) of Spaceflight News, pages 12-15, carried an article of mine titled "Composite HOTOL",

Compare to this design: http://www.secretprojects.co.uk/forum/index.php?topic=23384.0

Martin

Thank you Martin that is fascinating (though I wish I could read Russian). I never saw Cormier's canard carrier ship design before now - I can promise that I did not copy it! I wonder when he published it, whether it was before or after mine. But eight JT9Ds, phew!

 

[martinbayer]

Steelpillow,

Cormier published his design in 1979 in the AIAA Paper 79-0879 named "Utility of High Bypass Turbofans for a Two-Stage Transport".

Martin

 

[steelpillow]

Cormier published his design in 1979 in the AIAA Paper 79-0879 named "Utility of High Bypass Turbofans for a Two-Stage Transport".

Thank you. That probably explains his relatively large number of lower-power turbojets. Otherwise, our canard carrier craft are much alike.

I wonder what he envisaged for yaw control - those huge winglets would generate large structural forces if they had rudders attached. My own thought was a fore rudder on the nose pylon as it has a more rigid mounting, along with considerably greater lever arm than the main pylons. Alternatively, differential drag by messing around with the ailerons would be a more conventional approach (e.g. as used on the B-2 Spirit).

 

[flateric]

Quite interesting interview with late John Scott-Scott. HOTOL, RB454 etc

http://sounds.bl.uk/related-content/TRANSCRIPTS/021T-C1379X0032XX-0000A1.pdf

 

[flateric]

QI

Source: East, R.A., Hutt, G.A.: Vehicle Geometry Effects on Hypersonic Stability and Control. In: Proc. Symposium on Fluid Dynamics and Space, VKI, Rhode Saint Genese, Belgium (1986)

 

[flateric]

...

 

[flateric]

HOTOL as it was born

 

[FighterJock]

HOTOL as it was born

I think that is the version that HOTOL should have been before British Aerospace (at that time) changed it to the design that we all know.

 

[starviking]

HOTOL as it was born

Any more information on this configuration? There would appear to be attachment points and what may be umbilical covers aft of the payload bay. For a booster? fuel tank?

 

[flateric]

...

 

[Archibald]

Can't link the pdf it is too big

Flateric picture of primitive HOTL come from

https://webcache.googleusercontent.com/search?q=cache:ZT1b2VF13u0J:https://www.aiaa.org/WorkArea/DownloadAsset.aspx%3Fid%3D14414+&cd=1&hl=fr&ct=clnk&gl=fr&client=firefox-b

From HOTOL to SKYLON
British Spaceplane Programmes: Past, Present
and Future

 

[overscan (PaulMM)]

Additional pic of the early Hotol configuration.

 

[FighterJock]

Additional pic of the early Hotol configuration.

After looking at the early Hotol design, I was wondering does anyone know how many engines the spaceplane had?

 

[Archibald]

I often wondered how and why the RB.545 was classified by the British MOD from the beginning.
The classification made things much harder for Bond and co. For example, when pitching HOTOL to ESA at the rome conference in January 1985 they couldn't reveal the inner workings of the RB.545.
I did a quick browse and found this.
https://www.newscientist.com/article/mg13117843-400-technology-patent-office-reveals-hotols-secrets/

31 August 1991

Earlier this month, the British Patent Office finally released the details
of the revolutionary engine that would have powered Britain’s spaceplane
Hotol. Because of its possible military applications, the government put
a security order on the patents eight years ago.

The security order prevented British Aerospace, who were developing
Hotol, from finding overseas collaborators to help them fund the project
and the research foundered.

Suddenly in April, the government lifted the
security order and the patent office quickly processed them and issued them
on 14 August. Now they are available for anyone to read.

Looks like RB.545 was declassified... long after HOTOL was dead (1988 and Thatcher funding withdrawal).
For the record, Bond created REL in 1989 and started working on a different engine to get around the RB.545 classification (Satan, later SABRE)
https://www.flightglobal.com/pdfarchive/view/1989/1989%20-%200765.html

As to why the engine was declassified by 1991 - no idea. But Alan Bond must have been pissed-off.

When the patent was filed in 1983 by its inventor, Alan Bond, it was,
like all British applications, reviewed by a security board at the patent
office. The board referred it to the Ministry of Defence which judged the
engine of significance to national security and classified the application
as secret. Under the standard procedure for classified applications, the
patent then officially ceased to exist.

So that's how the RB.545 become classified.

All this, said Bond, can be done with ‘relatively standard gas turbine
and rocket engine technology’. Bond saw the real challenge being in design
of the heat exchangers. Work on a serpentine arrangement of small bore tubes
with very thin walls made from nickel alloys looked hopeful.

Rolls-Royce later found that when liquid hydrogen is used to cool the
intake air, moisture in the air caused ice to build up in the engine. In
the later patents, the company’s first idea was to use more automatic valves
which gradually open and close to reduce the flow of liquid hydrogen and
oxygen through the heat exchanger when the air is humid.

A year later Rolls-Royce found that the engine thrust then varied as
the heat exchanger valves operated. The company’s next idea was to keep
the rocket motor running in an idling condition at low levels of altitude.
When there is icing, the rocket power is increased to produce extra thrust
which compensates for the loss of power from the jet engine.

Frozen heat exchanger was the main issue (also for aerospaceplane and Japanese LACE)

Here is Alan bond 1983 patent for RB.545
https://patentimages.storage.googleapis.com/pdfs/0bfe59990ac43e571a1b/US5101622.pdf
https://patents.google.com/patent/US5101622A/en?inventor=Alan+Bond

Priority date
1983-12-23
Filing date
1984-12-20
Publication date
1992-04-07
Grant date
1992-04-07

 

[archipeppe]

Dear Grigory thanks for the find.
It looks more realistic than the final one.

Ciao
Giuseppe

HOTOL as it was born

 

[Michel Van]

Thanks Grigory, for the picture and data

i really like first version of HOTOL it would have been good SSTO, instead of later version this "flying Hydraulic system"...

 

[Archibald]

https://www.newscientist.com/article/mg13117843-400-technology-patent-office-reveals-hotols-secrets/

Rolls-Royce later found that when liquid hydrogen is used to cool the
intake air, moisture in the air caused ice to build up in the engine. In
the later patents, the company’s first idea was to use more automatic valves
which gradually open and close to reduce the flow of liquid hydrogen and
oxygen through the heat exchanger when the air is humid.

A year later Rolls-Royce found that the engine thrust then varied as
the heat exchanger valves operated. The company’s next idea was to keep
the rocket motor running in an idling condition at low levels of altitude.
When there is icing, the rocket power is increased to produce extra thrust
which compensates for the loss of power from the jet engine.

Here is that second patent
https://patents.google.com/patent/US5088280A/en?assignee=Rolls-Royce+Plc&inventor=Alan+Bond

And another
https://www.google.ch/patents/US5085041

 

[Hobbes]

are there any books on HOTOL? Or a decent 3-view drawing?

 

[GTX]

are there any books on HOTOL? Or a decent 3-view drawing?

Not sure about dedicated books though I have sen it mentioned in some. As for images, there is this, though it is not official:

 

[Hobbes]

Yes, I found that one too. Problem is it looks very different from images like this, that show a fuselage with a constant cross-section for most of its length. To me, these seem more feasible, as it's much easier to build a hydrogen tank as a constant-section cylinder compared to an off-axis cone.

and this one published by BAE Systems:

 

[flateric]

are there any books on HOTOL? Or a decent 3-view drawing?

a). https://www.amazon.co.uk/British-Secret-Projects-Britains-Shuttle/dp/1910809020
b). see attached

 

[Hobbes]

I just finished reading BSP: 5. HOTOL is only mentioned briefly.

Thanks for the drawings. Do you know where they came from?

 

[flateric]

Design and Operational Analysis of the HOTOL Auxiliary Propulsion Subsystems
J.B. Marshall and G. Statham (t)
British Aerospace Space Systems Ltd.
Argyle Way,Stevenage,England
1991

 

[overscan (PaulMM)]

Added a post from ages ago to topic here - https://www.secretprojects.co.uk/forum/index.php/topic,277.msg41339.html#msg41339

 

[overscan (PaulMM)]

Interim HOTOL designs

The An-225/Interim Hotol launch vehicle R. PARKINSON, British Aerospace Space and Communications, Ltd., Stevenage, England

 

[steelpillow]

Odd how some of these drawings have no discernible air intake. Is it perhaps supposed to retract for re-entry and landing?

 

[Hobbes]

Interim Hotol was a simplified design using rocket engines (instead of the airbreathing RB.545), to be air-launched from an An-225. So this had no air intakes.

 

[flateric]

sold for $$$ on eBay

 

[RAP]

BRITISH AEROSPACE HOTOL - AIR LAUNCH VEHICLE - PUBLICITY BROCHURE | eBay

PLUS 3 PRESS PHOTOS.

www.ebay.com

 

[Hobbes]

I'll try to acquire this (unless you're already bidding)

 

[Orionblamblam]

I have a scan of this. It's ok, but don't go nuts with spending on it.