Sugden Special 2,49cc model diesel engine

[Olli-Matti]

Wanted to share with you my fifth homebuilt model diesel engine project, that came to a finish atleast what comes to machining and turning parts.
I did build according the original plans from the 1954 and late Ron C's article was of great help also:

Building the Sugden Special

modelenginenews.org

I did deviate a little from the plans namely at venturi opening that is 6,0mm when plans have 1/4" and the
spray bar is also of 3,2mm in diameter when in plan it is 2,8mm. This results in a little bit
more conservative choke area but it is always easier to make a hole larger later than smaller later.

Also removed the backplate mounting lugs carefully and modified the cooling jacket and cylinder hold down flange a little
as being a home made design in the first place I figured that some artistic freedom can be taken here.

Engine weights in at a mere 112g which is not bad for a 2,5cc engine.




Video:

Sugden Special first run

 

[Olli-Matti]

sugden doing 14500 wih an apc 8x4 prop

 

[kadora]

Nice engine Olli. I am curious did you cast crankcase in sand
or it is lost wax casting.

 

[Mechanicboy]

I did deviate a little from the plans namely at venturi opening that is 6,0mm when plans have 1/4" and the
spray bar is also of 3,2mm in diameter when in plan it is 2,8mm. This results in a little bit
more conservative choke area but it is always easier to make a hole larger later than smaller later.

Olli-Matti

Great to see the engine is running.

Most often we choose the measurements that are closest to the inch measurements since we live in a metric society that everything should work regardless.

Greetings from the 5th generation roots of Finnish origin who living in Norway.

 

[Basil]

Very impressive. Nice build.

 

[Olli-Matti]

the casting is of great quality and made by Vincent Chai back in 2006. It is a permold die and it can be seen here: http://modelenginenews.org/gp3/sug_firstpour.jpg

I went ahead and modified it a little removing the backside mounting lugs.

rgds
Olli

 

[Gary C]

A beautiful example and very well made. A credit to you. My first knowledge of the engine goes way back to the Model Aero Engine Encyclopedia of which I still have my copy of the first edition. You can see a pdf of the build in chapter 25 here:

https://rclibrary.co.uk/files_titles/1996/Engine_Encyclopedia_RonMoulton_partB.pdf

 

[Olli-Matti]

one more vid on the subject. contains a lot of machining bits.
Sugden build video

 

[Basil]

Very nice work! Thanks for sharing.

 

[Olli-Matti]

Sugden sounds:

 

[minh-thanh]

Very nice work.
Congratulations !