View Full Version : Smiths electric pilot Sep.1

23rd Apr 2007, 10:25
Can anyone tell me what type of aircraft had the Smiths Electric Pilot Model SEP. 1.

Could it have been a Viking?

Many thanks

23rd Apr 2007, 13:04
Not sure about the S.E.P.1 I know that the Smiths S.E.P 2 was fitted to the Vickers Viscount. As following the accident of Viscount 803 Aircraft EI-AOM near Tuskar Rock, Co. Wexford on 24th March, 1968 an examination of components of the autopilot – a Smiths S.E.P.2 was done at Dublin Airport on 21st October, 1968.

25th Apr 2007, 13:44
Not absolutely sure but I think the first Avro 748 had a Smiths SEP 1 when I first flew the prototype G-ARAY during conversion training in 1967. I do know that the VIP Avro 748's for the Royal Australian Air Force were fitted with the Collins FD 108 system and that Avro's had a difficult job interfacing the Smiths autopilot system with the Collins FD system.

26th Apr 2007, 01:14
Viscount had SEP II .
As did Argosy and Merchantman and I would presume any other piece of British Blacksmithing from that era.
Might be wrong here but believe it evolved into Collins ?
SEP II = Seldom Ever Performs Twice :hmm:
However personally found it worked very well once you got used to a few little quirks like "flying down towards yer boots"

Dan Winterland
26th Apr 2007, 02:27
'Flying towards yer boots'. That brings back bad memories! Sounds the same as the Smiths MFS (Smiths Military Flight System) more commonly known as the Smiths Mystery Flight System - as fitted to the Victor and Vulcan Mk2s.

26th Apr 2007, 04:02
I would presume any other piece of British Blacksmithing from that era.

Dan I would guess you are right.:ok:

26th Apr 2007, 18:35
The core of MFS was actually Mk.10 Autopilot, which in civilian clothes was SEP2.

SEP2 was also standard fit on the Britannia and Comet C Mk 4 in RAF trim, where SFS (Smiths Flight System) was fitted.

The only real difference between Mk.10 and SEP2 (apart from various gearing changes) was the absence of the "Bomb" facility.

SEP1 was, I believe (a little before my time) the RAF Mk. 9 autopilot--which appeared on the Comet C Mk.2. No flight system as was later known, just the Zero Reader......a wondrous binary driven machine.

Smith's at Cheltenham used to have a small museum of their wares--fascinating for those of a technical bent. You could also eye the girls from CLC from the office window.........

27th Apr 2007, 02:14
I can say with absolute certaintly that the Varsity - and therefor most likely the Viking - had an SEP 1 Autopilot. In 1977 I removed a complete system one from a Varsity on the burning pan at Northolt for donation to Southall College of Technology.

Yes LFittNI, the Smiths MFS used on Vulcans and Victors was based around the military version of SEP 2 rather than the SEP 1. That Rate/Rate platform was certainly the way to go for tight attitude control. After leaving the mob and moving onto American built machinery, I was astonished to find the Pioneer-Bendix PB20 used in the B707 was a displacement autopilot with rate feedback. Whatever happened to British avionics? We were the cutting edge in the fifties yet lost the plot entirely in less than ten years.

28th Apr 2007, 01:34
Whatever happened to British avionics? We were the cutting edge in the fifties yet lost the plot entirely in less than ten years.

"Whoever comes first ....fails"


28th Apr 2007, 12:37

Yes, it's very sad to recall the demise. Caused, I believe, by two main factors--the prevalence of multi-nation aircraft programmes where political necessity forced a third-party avionics choice, and the late take-up of advanced semi-conductor technology in the UK.

I know that Elliotts tried to make a run with some very advanced (!) 8-bit technology post-TSR2, but found no takers.

A side-comment on the dear old Mk.10 autopilot----on the Britannia, the main amplifier unit was positioned by the Nav's leg, far too accessible for those wannabe techies. Balancing the mag.amps was a true art, as I'm sure you remember, not a science, and I lost count of the number of times I had to re-balance the pitch channel after the Nav tried to correct some minor (usually imagined)porpoise-ing whilst in flight.

One even asked me once if it would help if he "tried changing to the other gearing links"...........:hmm:

29th Apr 2007, 00:31
Wasn't it the Varsity with the SP1 that first did autolands? Thread here before about that, remember the b & w film though, Bedford or Cranwell I think, in real fog!

Dan Winterland
3rd May 2007, 06:08
Cutting edge? Anyone who had to fly with the MFS may disagree. Clever it may have been, but it wasn't that good. For a start, it only had 18 degrees up and 9 degrees down pitch info - the Victor Mk2 could easily exceed those at light weights. The compass display was clever if you were intercepting a localiser, but that was about it.

I came to the MFS from the Sperry STARS system which was a modern (for the time) system which was far far better. The MFS was a bit of a shock when I first saw it. OK, for it's time it was advanced. But thankfully the displays used weren't used on any subsequent system and thus becoming the norm. They were an ergonomic nightmare and DP Davis in his book 'Handling the Big Jets' states that generally there were a fairly unsatisfactory system. As he was the head of CAA certification at the time, he may have led to their demise.

Incidently, the Mk2 V Bombers had a autoland system which used the Smiths autopilot and a system called L Cable which was an aerial which ran along the ground out as far as the middle marker. This was very advanced for it's time and I think the first operational use of an autoland system.

3rd May 2007, 15:04

I'd forgotten what nostalgia was until I read Mk9, Mk10 autopilots and Zero Reader all on the same thread!!
The Shackleton Mk2 had Mk9 (SEP1) and the Shack Mk3 was fitted with Mk10(SEP2).
Balancing the mag amps wasn't just an art, it was a black art. I seem to remember the crossfeed channel being a bit sensitive at times.

How about G IV B and G7 mag compasses and T3 Bombsights for memory lane?????????????


15th May 2009, 20:23
Hi, I recently got a part of a Vulcan, called a gearing pad I am trying to find out about it, from another forum I have learnt it was part of the Smiths SEP11/ MK10 autopilot.
Could anyone tell me more about what function it had?
the writing on it reads
used on
code 107 SUE/2
ref no 6TB/1728
ser no 449/64
It also says
gearing pad
type J
(pre amp A/S)


17th May 2009, 16:52
If this is what I think it is, the Gearing Pad was fitted to the Mk.10/SEP2 Main Amplifier, and was accessible under a flap in the side.

Its main purpose was to alter the gearing ratios and feedback rates of the three main autopilot channels, pitch, roll and yaw, according to the required aerodynamic characteristics of the aircraft type it was fitted to. Each aircraft type would have its own specific pattern of links which altered the inductance dynamics of the magnetic amplifiers. AFAIR, it also enabled other attributes of the autopilot to be made "live" or not.

Thus, a standard piece of avionic equipment could be specified and ordered for many different aircraft types--good thinking, and a good example of early COTS.

Having written the above, I seem to recall it being referred to as "the Links Pad", so there is a chance that this example might be different!

Sorry m'lud, it's all a very long time ago...........

17th May 2009, 21:22
Thansk for your reply,
it was very informative

17th May 2009, 21:48
#10, LFNI: UK avionics demise due to: the prevalence of multi-nation aircraft programmes where political necessity forced a third-party avionics choice, and the late take-up of advanced semi-conductor technology in the UK. No demise: Smiths thrives in GE Aviation Systems, much of Ferranti and Elliott in SELEX/Finmeccanica.

No late take-up: Cat.IIIa, 12ft. decision height Autoland, Smiths on Trident/Belfast, Elliott on 1-11/VC10, slaved to Leader Cable at Brize Norton/LHR. First to market, where all then lapsed, in part due to clean-air removal of "dirty" coal (pea-souper smog now a dim memory), and in part to late-1950s' galloping pace of (now, IT): Autoland's early-1950s' origins at Bedford BLEU involved valves. TSR.2, Concorde, Sea Slug/Bloodhound/Thunderbird Mks.I SAMs were all adversely impacted by step-change in Automatic Data Processing. 1962 Bloodhound I "Affair": Ferranti had won pulse radar guidance, paid by MoS in 1953/4 to take licences from (AT&T)Bell Labs and Texas Insts. and thus become Europe’s 1st. supplier of silicon diodes by diffusion process. Fairchild’s planar/Bell’s epitaxial processes, ’58/60 led in ’61 to TI/Fairchild launch of medium-scale integrated circuits, applied by Ferranti in Bloodhound, omitting to mention it to MoA's pricers. £4Mn. repaid. They still won much on Tornado. Of 1960s' International Collaborative Projects (the alternative to which was no projects) Concorde was extensively Brit avionics; Jaguar 'S' had Elliott NAVWASS; Lynx has Elliott AFCS even in the Aeronavale variant. Tornado IDS was Elliott AFCS, TF 'E' scope and TV Tabular Display; Smiths HUD. Your 3rd. party choice point is presumably Elliott/Ferranti's loss of the Tornado Ground Mapping and Terrain Following Radars to TI, in R&D (they licensed their production/support). Both teams recovered from that setback. The digital data bus funded into Tornado, 1971, was in no way inferior to F-111A, F-15A. In exchange for US lead on the radar, FRG granted UK "excess" share of the rest of Tornado's common avionics suite, to UK's great benefit on Eurofighter.

17th May 2009, 22:41
When I was first posted to Lossiemouth in 1972 my job was carrying out 2nd line servicing of the SEP1(MK9) autopilot system this was fitted to the 8 sqdn Shackletons and as i recall it was very similar to the Sep2 (MK10)except the gyro unit was completely enclosed unlike the Sep2s gold fish bowl gyro unit.

18th May 2009, 11:44
UK avionics demise due to: the prevalence of multi-nation aircraft programmes where political necessity forced a third-party avionics choiceIn military aviation we can still see the remains of the British avionics industry, just as we can see the remains of our airframe capability in Airbus. However, in civil aviation where I work, there are three choices for avionics - Rockwell Collins, Honeywell and Thales. GB is limited to producing a few nice bits of very accurate test equipment.

avionic type
18th May 2009, 19:53
The B.E.A. Viscount 701s Vikings,Elizabethans, were fitted with S.E.P.1 and the 802/806 Argosy , Vanguard and the Comet had the S,E.P.2

25th May 2009, 21:02
Interested to see the negative comments regarding the ergonomics of the beam compass display. Always remember what a pain in the butt it was to change it on the Vulcan. Perhaps this explains the reason MFS wasnt fitted to the herc when Mk10b autopilot was installed. The sperrys C12 system seemed to be cheaply made but it worked, took up alot less space and was very easy to read and still had a "track" facility. I suppose the older hercs must be the last carriers of Mk10.
Just a final thought, I was once told the the rate/rate gyro technology was "liberated" from the germans post WW11 and handed to Smiths for development

3rd Jun 2009, 15:04
I did a lot of research into this a while ago, and dug up all kinds of articles and evidence. I distilled the research into a few pages, including a simplified schematic of the differences between SEP1 and SEP2, and posted them here:

Smiths Electronic Pilot (http://www.dh-aircraft.co.uk/systems/sep1.html)


3rd Jun 2009, 18:26
I flew the Smiths MFS/SFS as fitted to the Argosy and the Viscount 802/806 for 10 years and I thought it worked pretty well.

Mind you, it is now quite hard to remember the days before V Bars and Cross Hairs were invented.

3rd Jun 2009, 18:31
I should also answer the question ...

The rate/rate principle had been identified very early on. It was an ideal that many people working on automatic servo control were heading towards, but was effectively blocked until the advent of modern electronics. From that point of view, it's quite difficult to identify who thought of it first, but the first design is attributed to Andreas Minorsky in Russia. He emigrated to America in 1918, with his designs, and continued work with the U.S. Navy. The first sea trial was in 1923. It was not successful, and development was abandoned.

The German system, developed by Askania, Patin and Siemens, produced the first all-electric system in 1932. It was also the first use of the term, "autopilot". It was very comprehensive in what it did, very "modern", but too slow to respond. Trials were conducted with limited success.

The first successful rate/rate system was based on research by F. W. Meredith at the R.A.E., who commissioned Smiths Instruments to develop it. This became the Mk 9 for the military, and S.E.P. 1 for civil aviation, which was released in 1947.


3rd Jun 2009, 18:45
I certainly found there was a love/hate schism during my research. R.A.F. and B.O.A.C. pilots had an input into how it evolved, and how it relayed information. By and large, ex-R.A.F. pilots flying B.O.A.C. aircraft thought it was eminently logical and efficient, while pilots converting from other systems, for example Sperry, absolutely loathed it. That situation became worse as Comets, Britannias, Viscounts and Vanguards were taken up by other operators with a broader mix of people.


17th Jun 2014, 21:05
The Smith Automatic Pilot was one of the most widely used first auto pilot systems, especially in the Royal Air Force - RAF, during WWII. "The used of this system enables an aircraft to be flown in almost any weather condition, thus relieving the human pilot an immense amount of physical and mental strain." The guiding principle of the auto pilot system is an air-driven gyroscope. This system was manufactured by the Messrs. Kelvin, Bottomley & Baird Limited, many of the instruments used, designated the K.B.B.-Kollsman type, were designed by the American genius inventor Paul Kollsman and his Kollsman Instrument Company.

The system was not just a gadget or just a night or 'blind-flying' instrument, but was a mechanism of the highest reliability and precision, and was "used exclusively throughout the RAF for eight years" by the year 1941. The unique and reliability of the Smith automatic pilot enable it to withstand the "most arduous conditions" encounter in the RAF. Mark III and Type II were available in 1940.

Ernest M. H Appleby, an Instrument Maker, wrote : "I had the privilege of briefly assisting Paul Kollsman when he spent some time in England at the (K.B.B.-Kollsman) Basingstoke plant, which was running up to full production in 1938-39, 24 hours a day, in preparation for the coming war. ..... Paul Kollsman was, to my mind, the most outstanding aeronautical instrument designer of the 1930’s.

"An example of his design genius was the British-produced MK X1V 3-pointer altimeter, which, in one giant step, took aviation instrumentation from the fusée chain barometer / altimeter to a precision instrument. The Kollsman designed altimeter also incorporated a unique temperature compensation system which has never been bettered... It corrected the temperature change effect on the aneroid capsule sensor with changes in altitude, a non-linear function; the design was brilliant in its simplicity. These instruments equipped a great proportion of the Trainers, Fighters(Rate of climb indicator Mk.3P as used in Vampire, Hunter etc. Mk.XIV altimeter as fitted to late Spitfires, Meteor, Vampire etc), Bombers, Reconnaissance, Meteorological and Transport aircraft of the Royal Air Force, the Royal Navy Fleet Air Arm, the Army Air Corp. and the Air Forces of the Commonwealth of Nations."

Kollsman went on to be a premier inventor with fundamental discoveries in jet engine technology; medical syringes; water purification and desalination methods; and ground breaking inventions for Electrode-deionization and electrodialysis. Perhaps one of the most unknown top 20th Century Inventors with over 200 useful patents.

Take a look at this recent patent: US patent 8051655, and who do they cite as the key inventor?...the first 13 fundamental jet engine patents citations refer to one man - Paul Kollsman! (US patent 8051655 - a modern "method and system for mechanical and electrical power generation".) Kollsman was known as the shy brilliant genius.

19th Jun 2014, 10:38
Aah! Temperature compensation of the altimeter aneroid capsule. Many a cup of tea went stone cold at Epsom Square as victims, er, candidates, struggled to describe its operation to their Airworthiness Surveyor inquisitors.

The problem was, different books described two different versions and one of them was wrong - the one written by an Airworthiness Surveyor [whose name sounds like a device used by artists]! :hmm: