BJ Cicada (oz13685)
About this Plan
BJ Cicada. Model aero engine.
Designed by Chris Boll, Ron Jenkins. CAD drawings by Ron Chernich.
For the full story on the BJ Cicada see: http://modelenginenews.org/cicada/index.html
Quote: "The BJ Cicada is a 1.36cc side-port, compression ignition engine designed by Chris Boll and Rob Jenkins (hence the 'BJ') for home construction from barstock. This design joins Chris' earlier BollAero 18 (oz13680), which in turn, was modeled after the smaller ML Midge (oz13675) designed by Mark Lubbock.
Chris and Rob generously offered plans to all readers of Model Engine News, so they were modelled in Alibre Design by Ron Chernich and made available for download in December, 2012.
The BJ Cicada is a simple sideport diesel with a bore of 0.437" (11.1 mm) and a stroke of 0.554" (14.07 mm), for a displacement of 0.083 cuin (1.36 cc). This is a beam mount engine and the crankcase could be hacked out of a 1.6" length of 1" square bar stock with a hacksaw and file, though milling would be a lot easier. No screwcutting is required, but some soldering is. Being a cool running diesel, you could get away with high temperature silver solder on the venturi boss to cylinder joint, but silver brazing will ensure no bits ever melt off (as sometimes happened with the old ED Penny-slot).
This is the sort of engine that can be made from a reasonably stocked scrap box and even if you have to buy stock, it won't dent your bank balance. It's simple enough for beginners, with plenty of scope for experienced model engineers to indulge in some self-expression. It even has cylinder fins that Westbury would approve of!"
Direct submission to Outerzone.
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(oz13685)
BJ Cicada
by Chris Boll, Rob Jenkins
from Motor Boys International
2012
1.36 cc
Engine Diesel
clean :)
complete :)
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Submitted: 08/03/2022
Filesize: 401KB
Format: • PDFbitmap
Credit*: EdHolly
Downloads: 812
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User comments
Hi all, I have so far built the Boll Aero 1.8 and the BJ Cicada [pics 004, 005], and although they are not the finest pieces of model-engineering, they both run! I am at the moment working on my version of the MAN Little Dragon glow motor, also from the Model Engine News collection. I have included a photo of my Cicada with the Boll 1.8 that I made earlier [pic 006].Dick Edwards - 15/03/2022
Thanks for the photos, Dick. We actually have the Little Dragon plan coming along in a few days, too.
SteveWMD - 15/03/2022
Awesome to see the engines being added to OZ! Any chance of adding an engine category? Browse - By Category and see the only the engines...
scottyp - 15/03/2022
Good point. Working on that now. You can try this page, as a test: https://outerzone.co.uk/plans.asp?cat=Engines that should work.
SteveWMD - 15/03/2022
When i checked CAD drawing for BJ Cicada I see collision of conrod with Cylinder when the crankshaft 90 dig position. There is something wrong with sizes as BollAero 18 has no collission between conrod and cylinder surface at 90 dig.
Nikolay - 29/02/2024
hmmm. See the earlier comments, Dick Edwards has built this engine, and it ran ok for him. So I guess the drawings are correct? He didn't mention collisions.
SteveWMD - 29/02/2024
Drawings require to be corrected. The conrod (4 mm thick.) comes in collision with inner cylinder surface when the shaft at 90 dig position or about. Or cylinder to be elevated above crankcase stoke to be reduced.
Nikolay - 29/02/2024
construction blog at: https://www.homemodelenginemachinist.com/threads/b-j-cicada-engine.25014/
pit - 29/02/2024
Thanks pit. Aha reading through that build log, it seems there is indeed a problem with the plan. So, yes, it would be good if a corrected plan could be posted here. But it is beyond my skill to edit and correct this plan. Anyone?
SteveWMD - 01/03/2024
Hi Steve, pit is right about the conrod clearance at the bottom of the liner when the crank is at 90 degrees from top/bottom dead centre. I seem to remember I overcame this problem by milling a shallow slot on opposite sides of the liner skirt to clear the conrod. This can be done quite easily with a file, the angle and depth adjusted by trial, There are several youtube videos showing Cicadas running very well so I assume their builders must have done something similar.
Dick Edwards - 01/03/2024
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- BJ Cicada (oz13685)
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Notes
* Credit field
The Credit field in the Outerzone database is designed to recognise and credit the hard work done in scanning and digitally cleaning these vintage and old timer model aircraft plans to get them into a usable format. Currently, it is also used to credit people simply for uploading the plan to a forum on the internet. Which is not quite the same thing. This will change soon. Probably.
Scaling
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