Boll Aero 18

[radfordc]

The Model Engine News website provided free plans to the Boll Aero 18 diesel engine.
http://www.modelenginenews.org/plans/BollAero18.pdf

I started this project last week and have the case and cylinder parts done so far.

Charlie

 

[radfordc]

Here is what has been done so far.

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[Deferr]

I am anxious to see the process for this build. Very neat design. Can't Wait!

 

[Metal Butcher]

Hi Charlie, and welcome back!

Its been a while since I saw you post a build, which was the John Deere.

I hope everything is O.K.

-MB

 

[Maryak]

Hi Charlie, and welcome back!

Its been a while since I saw you post a build, which was the John Deere.

I hope everything is O.K.

-MB

Me too.

Best Regards
Bob

 

[GailInNM]

Coming along nicely Charlie.
The Boll is a nice size and should be a good runner.
Gail in NM

 

[radfordc]

Thanks. I still lurk here everyday to see what others are doing. I just haven't been in my shop for a long while.

Charlie

 

[radfordc]

Today's work was finishing the machining on the cylinder and making the piston, rod and contra-piston.

View attachment IMG_0258[1]

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[radfordc]

Two steps forward and three steps back. I had to make a new piston and contra-piston since the first ones had zero compression. Much better now. All that's left is to finish the carb.

Charlie

 

[slick95]

Dig that engine Charlie,

You going to mount it on a plane and fly it? Nice build

Jeff

 

[radfordc]

I don't think it will ever fly. I'll be happy if it ever starts!

Charlie

 

[Metal Butcher]

I don't think it will ever fly. I'll be happy if it ever starts!

Charlie

Nice airplane engine Charlie. I am confident that you'll get it to start.

Remember the lyrics to that old song, "Don't worry, Be happy".

-MB

 

[omidn]

hi dear:
i want to build a bollaero engine,but i have some problems,if u can help me i will be graetefull.i have the plan and i see your post in the forum and photo of your work.these are my question about the plan:

1-i don't know what is the contra-piston and where be should it placed?
2- what is the fuel of bollaero18?
3-i can't understand about fuel sytem in plan?why the exhust hole and fuel injection hole are in the same level?how does fuel system work and how does is spray fuel to cylinder?
4- can u send how do parts(piston,contra-piston,...)place in the plan?(their sequences)
5-what is "mill transfer pessage"?
i apologize if i write many questions or my english grammer is not good.
i am waiting for your reponse.

plz send e-mail: [email protected] :bow:

 

[radfordc]

I can't really provide all the info you want, but I can recommend a site that does have it. http://modelenginenews.org/ This site covers many of the technical items you're confused about.

Charlie

 

[omidn]

thanks dear,i read that site but i can't find may answers in that,can u help me?what is the fuel of the"bollaero18"? :bow:

 

[John Rudd]

thanks dear,i read that site but i can't find may answers in that,can u help me?what is the fuel of the"bollaero18"? :bow:

The fuel is 'special' diesel fuel

Its a mixture of kerosene/ether/castor oil and IPN......

Castor Oil 20 - 25%
Ether 30%
Paraffin (Kerosene) 45 - 50%
Iso-propylnitrate 2 - 2.5%

 

[LADmachining]

Hi Omidn,

The fuel for the engine is the same as for most other small diesels - a typical mix is equal parts of ether, kerosene and castor oil. The engine will run on varying mixtures of these three ingredients.

Most of the questions you have asked are on the Modelenginenews.org site - the fuel question is answered in the FAQ (use the navigation menu on the left of the screen).

The plan would be much easier for a beginner to understand if there was a cut-away drawing of the engine.

The inlet and exhaust port holes in the liner are at different levels - this is what sets the timing. The position of the holes in the crankcase do not make any difference to the engine timing.

The fuel from the tank connects to the bottom of the spray bar (part 8-3). The fuel is drawn out of the spray bar by the air passing through the venturi into the engine. The amount of fuel delivered is varied by the needle (8-4), and the amount by which is obscures the spray bar jet hole (#61).

The contra-piston fits into the top of the cylinder, the flat face of the contra-piston facing the main piston.

 

[Bill Mc]

Hi Charlie - I can see where the Boll-Areo 18 will become a great beginners (newby) project. The materials are not hard to obtain and the plans are explicit in detail. Probably the beginners will ask for more rudimentary things like photos of actual machining operations and how to set them up. We must strive to assist these fellows as much as we can. This is one of the main reasons for this wonderful site of ours. The only critical item is to ensure that tolerances are met. They MUST be very accurate to ensure adequate compression as this is a diesel engine. This engine could easily be modified to support a glow plug to lessen the constraints placed upon it. - Billmc

 

[omidn]

hi dears LADmachining and John Rudd:


i am very grateful from your attention to my question.i am a beginner in model engine.can i have your e-mail address to ask some question if it is possible?

thank u very much. :-*

i have one question,what is the "mill transfer passage" in the plan?

 

[Paulsv]

Hi guys! I am a relative newbie, both here on the site and to model engineering. I am interested in the BollAero as a possible first project. I am also looking at the MLA-17 (http://www.statecollegecentral.com/metallathe/MLA-17.html), another compression ignition (diesel) engine. Its plans come with a 30 page booklet that gives a lot of explanation, which I as a newbie find helpful.. The MLA-17 does not have a contra piston, which seems simpler, but on the other hand it has a threaded backplate, which I am a little afraid of.

It's not real clear from the plans, but as I understand it, the contra piston is a press fit in the top of the cylinder, so that it will stay in place, but still be able to be moved by the compression screw, in order to adjust the size of the compression chamber. Is that correct? It seems that the fit of the contra-piston in the cylinder would therefore have to be very precise, and presumably would have to be lapped to a precise fit. Do I have the concept correct?

Charlie, I hope I am not hijacking your thread by posting this question here. Your pictures and description are great. You make it look easy, and that gives me some encouragement, so I appreciate it.

Also, for Omidn, you should check out this site: http://www.modelenginenews.org/ If you click on "Resources" in the left column, and look at the "FAQ" and "How To" sections, there is a lot of helpful information, including information on the fuel and how to obtain it.