KEITH BEAUMONT 1

Lauriew, Please be inspired ! the whole point of sharing work is to inspire others. If you are looking fo a first project,I can recomend the Boll- Aero designs by Chris Boll. They are all "no nonsense" designs to encourage people to make an engine. All ldrawings are available on Outerzone site. The Boll-Aero 1.8cc Diesel is a popular 1st project. Several of them are on U-tube. Keith.

In my youth,many years ago, as a keen Aeromodeller, my favourite engine was the Mills 1.3cc Diesel. At one time I had four of them.They were popular due to their reliability and easy starting from hot or cold. The design was about right for the style of modelling at that time, being free flight and control line in reasonably modest airframes. I have often wondered why the design was not taken further and al arger version produced beyond the 2.4cc that did appear. Recently visiting the exelllent site hosted by Adrian Duncan (AdriansModelAeroEngines,com) for historical information of "Classic" model engines, I found a reference to a prototype 5cc Mills that was not continued with. Its external design was not exactly attractive,trying to get the weight down,etc, but I then formed the idea of making a 5cc version as my next project. Several years ago I made the 1.3cc version, from Ron Chernichs "Motor Boys" drawings, so a straight enlargement from these was decided on. Most of the engines I have made have been from bar stock,with a few from castings. A rough sketch of the size of the block of aluminium for the crankcase made me decide it would make too much swarf, so decided to make a pattern and have a casting made in LM25 Ali. The design of the cylinder porting and timing has been copied exactly from the 1.ccc design. The only changes I have made to the internals is to add a ball race to the rear crankshaft,alter the prop driver to to collet fixing rather than taper the shaft and drill the crankshaft for lubrication of the front bronze bearing. With the crankshaft, I decided not to machine this from solid , but to build it from separate parts. I had tried this once before on another engine, but it failed due to me having a thread to a shouder for fixing the disc to the shaft,then silver soldering. It ffailed on that shoulder after a backfire. This time I have kept the shaft parallel and thge hole tthrough the dsc a sliding fit.The front side of the drilling was very slightly chamfered, to aact as a reservoir for the brazing material. It all went together very well and I have clean brass witness rins each side. The aluminium casting did not machine well and has a lot of micro porosity that can be seen on the machined surfaces. This has prevented me bead blasting th crankcase, as I normally do. So, decided to have the crankcase finished black. After testing several high temperature painnts for resistance to Ether/Castor oil, Igave up and arranged to have it Powder Coated with a local company, using a Polyester based powder coat that proved to be immpervious to Diesel fuel. The first Powder Coating was not a success visually, as gas expansion from the porosity when heated to 200 C, blew bubbles in the paint which the collapsed, leaving craters on the surface. After rubbing down, filling the craters with JB Weld, fo[[owed by another careful rub down, the second attempt at coating was much better,but still left a couple of small marks. Now the engine is finished and assembled, I amqute pleased with the overall appearance and I think it resembles the Mills smaller brothers. An accurate measurement of the finished engine gives a swepped volume of 5.07 cc On the test bed, I had no trouble in finding the point of ignition.Some really vicious back fires once or twice that nearly knocked my "chicken stick"out of my hand, but then the magic sound of it bursting into life for the first time! So far I have had a total run time of 30 minutes, in a series of around 4 minute rich runs, with the occasional burst to full 2 stroking. Fitted with a 12"x 7" APC propeller, using Model Technics 1000 fuel. Max RPM of 6950 to date. It has all the typical Mills characteristics of superb starting. Hot or cold it starts first flick after a prime. All together this has been a satisfying ptoject.

The engine was really far from zero running in. Every engine I have made is set up on the lathe,minus contra piston and turned over for an hour at 500 RPM, being flooded with plenty of oil at the same time, before finally reaching the test rig. When it is running, the NV is set to rich,with the occasional tweak to smooth running. That is when I took the photo of it running. All my engines have improved compression pressure after the running in regime I follow. Experimenting with different props is part of the fun. I have a static thrust rig and using a mixture of props with an engine, using that ,gives some suprising figures,somtimes. If I break something, I just make a new part, but that does not happen often. Thank you for your comments regarding engine, Keith.

None of the engines I make ever get further than the test bench. My days of flying are many years ago. I see no problem in seeing if an engine will run on various props. To hear it start for the first time is always the exciting part. That ,surely is a useful purpose. Keith.

Hi Rich, Thanks for comments. The tank was made from 20mm diameter x 2 mm wall, Acrylic tube, with an acrylic bottom ,with location stub and bonded with super glue. 26 tpi screwcut to locate with simlilar thead in Ali lid. If you are thinking of making it, I suggest you read my earlier post regarding it,on the Model Engineer Forum. I put a few more details on that. Keith.

Interesting comment,Brokenenglish. What disaster are you predicting I avoided?

During a recent perusal of the very informative site, run by Adrian Duncan,for those interested in model I/C , engines, www.adriansmodelaeroengines.com. I discovered information and drawings for this 1950s design in the alphabetical list of model engines in the "Engine Articles"section. As it was possible to make it from bar stock and I had sufficient material to hand, I decided it would be my next project. The article mentions it has been made by several of the "Motor Boys" from the late Ron Chernich's Model Engine News site and includes photos of finished engines. In partiular, it was the photo of Ken Croft's engine that attracted me, with its British Racing Green anodised parts, so it his engine that I have copied. Two sets of drawings are on the site.The original set, all on one page, are from an article published in the, now defunct, Model Maker magazine of June 1952. The other set of six drawings are CAD and produced by Ron Chernich. It is these drawings that I worked with. When trying to start this engine for the first time, I found the ignition point quite quicklywith a 6"x4" APC nylon prop fitted, but it would not go over TDC whatever I tried. It just bounced back and forward. Reducing compression did not cure it and there were no tight spots. The engine was originally designed for tether car use.The old drawings include a flywheel and I wondered if the timing is set for flywheel use. I therefore changed to a heavier 9"x4" APC nylon prop and it started second flick. The fuel tank holds fuel for a two minute run. In the attached photo of it running it is turning over at 5800 RPM, using Model Technics 1000 fuel. No gaskets have been fitted and there are no leaks, Clean oil is from the exhaust, so everything is where it should be. It is a not a very noisy engine, with a sound very reminiscent of the Mills 1,3 cc

Thanks for reply ,Bob. The mail has totaly vanished from my PC, but I have now found it is still on my phone,so I will be now able to transfer it to myself. Keith

A few days ago I received a free digital copy of the latest Mag from Mortons,in appreciation of being a Forum user. At the time I only quickly looked at it with the intention of reading it more fully later, but it has vanished. Has anyone any knowledge of whether it was a one off occasion,or I have somehow erased it? Keith

Hi Jeff, Photo of the straight through pipe version. Keith.

Hi Jeff, That is interesting information. I have only ever purchased this silencer from new and at the time cannot remember it being listed for size of engine. The centres of the mounting lug was what made me buy this one. I ended up making a multi pipe,straight through , but curved unit, more for directing where the exhaust castor went ,than trying to lower the sound. I have a photo somewhere and will post it later. Keith

Seeing this mention of the Jones .61 made me reach for my note book for when I made one from the Hemmingway kit,6 years ago. A friend had made one a year before and warned me that it was very noisy, as no provision is made for fitting a silencer. To enable me to fit one I altered the size of the exhaust aperture to allow fitting an extention plate with mounting holes for an OS silencer. My notes show that I had a lot of problems with overheating. I was getting top speed of around 10,000 RPM and slow at around 2500RPM,I tried different fuels , changed spacers in the head to try various swish band sizes,etc,but still it would always show signs of overheating. At one run that had some odd results, I found after a check that the main PH bearing had twisted in the housing, having the obvious changes to the timing and fuel intake. I the decided to remove the silencer. My notes say, in capital letters, THIS IS A DIFFERENT ENGINE !. Further testing was therfore carried out without the silencer and the overheating problem stopped Keith.

Hi hillclimber, How is the build of the engine going?

I am in the process of trying to mend an OS 10 with a broken lug, with the same 300c rods Trying out various test pieces before comitting to the actual crankcase, has not been very succesful without the use of a special flux for Ali Soldering. So I can sympathise with your efforts. I am not sure how high I can heat the crankcase safely too. Keith.

That is sensible advice from Jeff2 wings. I would recomend the bar stock designs by Chris Boll. all available on Outerzone. I have made all 5 of them. It seems that the most populer of these is the 1,8 diesel. Keith