Model Range

Probably because of their somewhat convoluted evolution, identification of engines within the ED range is more than a little confusing. The earlier engines were designated using a mark number (Mk) and, in most cases, a model name. Later engines simply had a name. For example the "Bee" was originally designated as the Mk I, the 2cc "Penny Slot" side-port was the Mk II, the 2.49cc front rotary valve was the Mk III, and the 3.46cc rear rotary valve "Hunter" was the Mk IV. While this all has an air of practicality, the mark number does not correspond to the chronological release order. To compound the confusion, some of the engines carry Mk numbers to indicate the variants, while most have individual design revisions designated by a series number.

Mk II and CS	Mk I "Bee" series 1	Mk IV "Hunter"	Racer
Mk III	Baby	Miles Special	Hornet
Super Fury	Super Fury Marine	Mk I "Bee" series 2	Pep
Cadet	Hawk	Racer Mk6	Mk V "Hunter"
Mk V "Hunter" R/C	"Hunter" Marine	Mk V Hunter marine	Mk V "Otter" Marine

Click on the images for individual engine profiles

 

Serial Numbers

From 1947 up to the end of 1959, ED used a simple code to identify the type, batch number, sequence number within the batch, and the year of manufacture. The location varies with the engine type although the edge of a mounting lug became the common position on later engines. In general, the serial numbers take to form:

    <type code><batch-month>  <sequence number>[/]<year>

The scheme allows the month and year of manufacture to be established reasonably well. However, to preserve confusion in an imperfect world, some engines place the batch-month code before the type code. In some cases, the slash between sequence number and year may be absent, but once you know what to look for, making adjustments for the occasional deviation is not hard.

The month is identified by a letter starting with A for January. The letter I was left out, most likely to prevent confusion with the number 1, so August is J. The sequence progresses up to M for December, finishing with an "N" group that we suspect was an extra batch scheduled to cater for the Christmas demand.

The sequence number is effectively a count of the type produced during the batch/month. So it is possible to have multiple occurrences of the same sequence number in the same batch for different engine types. Given a large enough sample of serial numbers, this value provides a measure of production figures for the engines and four digit numbers are not uncommon for the popular types.

Finally, the year is sort of like the good old "Y2K bug", only worse: even the decade digit is generally missing! It seems crazy that whoever devised this scheme did not expect the company to last ten years, but there you are: (mostly) a single digit only to denote the year. Some engines will have a "5" digit added so that, for example, a 1947 Comp Special could be distinguished from a 1957 one. In other cases, you need to intuit that the year must be 1957 because that type of engine did not excist in 1947! This only applies to the 50's though, no instances of an added "4" have ever been reported.

The codes allocated to the types were:

To take an example, ZC 208 6 is a Hornet (Z), made in March (C), of 1956 (6) that was the 208th engine completed in that batch. In this case, there is no slash between the sequence number and the year. This is not uncommon, especially in the later engines, but generally there is a wider space between sequence number and year allowing you to guess whether there are one or two digits for the year. A certain wry sense of humour is also evident in allocating Z to the Hornet. Think about it. What sound does the insect hornet make?

The serial numbering was not always consistent. Taking the Mk III for example, the type-code "3" has been observed both before and after the batch-month code letter. Marine versions generally have the letter "M" prefixed to the type code.

After 1959, ED changed to a letter to indicate the year, so A = 1960, B = 1961 and so on. After 1963 (the year of The Fire), it all went to pot until about 1966 when a new system came in.

Release History

In summary, the model designation, the major initial introduction dates and, where possible, the designer or consultant designer are as follows:

1946	Mk II 'Penny slot' 2cc	rear sideport induction (likely an early Basil Miles design).
1948	Mk I Bee 1cc	series 1 - rear rotary induction (again probably a Basil Miles design)
1948	Competition Special 2cc	rear sideport induction (Basil Miles)
1948	Mk lll, 2.49cc	front rotary induction (Basil Miles)
1949	Mk IV Hunter 3.46cc	series 1 - rear rotary induction (Basil Miles)
1950	Mk IV Hunter 3.46cc	series 2
1950	Racer 2.46cc series 1	rear rotary induction (Basil Miles)
1951	Racer 2.46cc series 2	webs added between bearings
1952	Baby 0.46cc series 1	front rotary induction (designer currently unknown)
1952	Baby 0.46cc series 2	front rotary induction (designer currently unknown)
1952	Hornet 1.46cc	rear rotary induction (a derivative of the 'Bee')
1953	Miles Special 5.0cc.	manufactured by Basil Miles at home and distributed by ED
1953	Racer 2.46cc series 3	solid metal between bearings
1953	Mk4 Hunter 3.46cc series 3
1954	Mk4 Hunter 3.46cc series 4	(shortened shaft design by Basil Miles)
1955	Racer 2.46cc series 4
1955	Bee 1cc series 2 'Q'	Completely revised
1956	Bee 1cc series 2 'X'	revised case, 3 transfers
1958	Fury 1.46cc series 1	reed valve induction (possibly a Basil Miles inspired design)
1959	Mk4 Hunter 3.46cc series 5	RR (R/C introduction)
1960	Mk4 Hunter 3.46cc series 6	RR (improved R/C variant)
1960	Super Fury 1.46cc series 2	rear rotary induction (Gordon Cornell)
1960	Otter	marine drum valve with throttle and silencer (Gordon Cornell)
1960	Pep 0.8cc	front rotary induction
1961	Bee 1cc series 2 'V'	4 transfers
1962	Hawk 1.5cc	front rotary induction (Webra)
1962	Cadet 1cc	rear side induction, and designed to carry a silencer (George Fletcher)
1963	Racer 2.46cc series 5
1969	Racer 2.46cc series 6
1970	Super Fury 1.49cc series 3	rear rotary with RC carburettor available
1972	Condor 10cc	front rotary with silencer and R/C carburetor by George Fletcher.

Note - there were marine versions of many of the engines and by arrangement, some of the Taplin Twins were manufactured by ED.

While the previous list includes the majority of the popular engines for which ED were more readily recognized and which mostly carried the ED title, other manufacturers products were available under licence from ED or were distributed by ED as part of its product range. It would also appear that ED owed much of its success to the design prowess and determination of Basil Miles, who was one of the original founders.