# how to get the bollaero 18 started



## deetzy (Apr 5, 2012)

I recently graduated from school, our final project was to machine and assemble the Bollaero 18 engine, I was the first person to complete the project in the school, and the only one to complete it in my class, i,m have trouble trying to start it, if any could give me some advice it would be much appreciated

                                        deetzy


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## Blogwitch (Apr 5, 2012)

I don't know if these posts will help

http://www.homemodelenginemachinist.com/index.php?topic=7796.0

http://www.homemodelenginemachinist.com/index.php?topic=8084.msg85375#msg85375

http://www.homemodelenginemachinist.com/index.php?topic=15404.0

http://www.homemodelenginemachinist.com/index.php?topic=8472.0

It would also be nice if you could introduce yourself as well, just so that we know who we are talking to.


John


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## deetzy (Apr 7, 2012)

john, thank you for the information sorry for not introducing myself, my name is Jeff, nice to meet you, i have some further questions about this project number one is when I intially made this engine i had to make a new contra piston and i made a new piston as well now how tight should the piston be? i made it so that it slides smoothly in the cylinder and i made the contra piston a little tighter so that its more of a press fit. is this where I've gone wrong at? I read on a site that the contra piston should be pressed in at 4 pounds of pressure. also i used a fuel mix that i found on the net i live in the middle of nowhere there isn't a hobby shop near me so i think that maybe i need to get the nitro fuel any help would be appreciated thank you very much for the info again

                                   deetzy


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## tomol409 (Apr 9, 2012)

Bollaero is a diesel engine and does not run on nitro fuel. That is for glowplug engines. Diesel fuel is bascally one third each of paraffin, castor oil and ether. Amyl nitrate can be added at a very low percentage, that is if you can get it! 
  The fit of the piston is easily determined by the amount of compression obtained, which needs to be pretty good to obtain about 16/1 compression ratio required. The contra piston must be capable of being firmly moved down by the compression screw, and must be able to return upwards. If the cylinder is primed through the exhaust port and the prop flicked, the contra piston will back jump up with a click. If not it will be too tight.
  Diesels can be primed either by palcing the fing over the intake and flicking the prop over about three times , then a very quick sharp flick may start the engine. Failing this, try a direct small prime through the intake. The third way is to prime into one of the exhaust ports. You will have to find which method suits your engine.


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## tomol409 (Apr 9, 2012)

Got chopped off there before correcting and finishing off the post.
   The prop needs to be set at the 20 past 10 position. The flick must be as fast as can be mustered going round 180degrees. Keep increasing the compression until a distinct hardness begins to creep in then back off a little, which should be near the right compression, and keep flicking. Hold the compression lever and if the engine starts, increase compression slightly. Needles are usually about two full turns open if the taper is as usual, and will need closing slightly to peak up the revs. Compression can be increased a little but the engine will run rougher when over compressed.  Happy flicking.


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## deetzy (Apr 9, 2012)

Thank you very much for that info, Tomol409 I will try it out when I get home the fuel mix that I am using is 25% castor oil, 31.3% kerosene, 48% starter fluid. but i will try this out and see what i get. thank you very much


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## Admiral_dk (Apr 9, 2012)

As much as I love this place on the net - when it comes to small airplane engines - especially diesels (compression ignition) - you really should check http://modelenginenews.org/

Ron is one of those who has build and flown them for many years and his site has some very good articles (with pictures) on building these engines and how to (start and) run them.

He tells you how to make a contra piston that works every time and how to lap the piston so you get it tight enough - a compression about 1:18-1:19.5 is needed for them to run.


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## Ramon (Apr 9, 2012)

Hi Deetzy, welcome to the forum. As a relatively newbie on here myself I'm sure you will find it a most friendly, informative and helpful place to spend time on.

I can really sypathise with you as I too found my first diesel, a commercially produced AM10 1cc, just impossible to start even with the readilly available correct fuel. By chance I met someone who was well versed with such and with his help and advice it soon burst into life at my hands. The problem was the size of propellor - a very light 7 x 4 nylon had been bought - fine for once bedded in and in a model but rather too light for that initial start and early runs. A larger wooden prop gave a better flywheel effect and once the correct setting was found it was off though the 'flick' had to be learnt too. To say I drove my mother to despair with the noise would be an understatement. I was just thirteen and that was some fifty four years ago. Since then I have operated and refurbed many small diesels over those years but only recently actually made engines from scratch. These have all been diesels and all are 5cc capacity - when they ran it was like that small AM10 all over again so I can well appreciate your disappointment in not being able to get yours to start.

I would like to add to 'Tomols' good advice but first, before you wear your arm to a standstill endlessly flicking (I would strongly advise against using any form of electrical starter - at such small size if the engine becomes flooded it is so easy to bend the conrod or do other internal damage) it is essential to be absolutely certain you have _good_ fuel. I have often seen reference to using starting fluid as an alternative to ether in diesel fuel but have never tried it. However your proportion of kerosene to the 'ether' content is to me the wrong way round. As already said a good basic mix is 33:33:33 - not a great fuel for performance especially without an ignition improver (you are extremely unlikely to source amyl nitrite or nitrate these days) but it will work. Usually Iso Propyl Nitrate -IPN- is used as an ignition improver. To improve performance reduce the oil (22 - 25%) and ether (25 - 30%) and increase the kerosene. If you do not have fuel that you _know_will work then you truly could be flogging the proverbial dead horse - thinking your engine (or yourself) is at fault when it isn't.

Okay, if your fuel is correct and you have a reasonably sized propellor (preferably wooden) - 8 x 4 or a 9 x 4 cut down to 81/2 would be ideal - how about your engine. Being right handed, I would fit the prop at 'ten past eight' as it comes on to compression, less than this the prop tends to drop below horizontal making a steady 'straight through' flick difficult; higher, more toward the 'hour' you will not get the impetus through compression. Starting technique however is very much how you develop it into what suits you best but you do have to get the piston _rapidly_ over the point of compression

The piston / liner fit in a diesel is much more critical than it perhaps needs to be in a glo(nitro) engine though we are talking very small tolerances between the two. If you lapped the bore did you lap the piston to it - ie in situ - to get an exact fit? The piston should start to feel springy against the compression as soon as it passes the exhaust port. If you squirt a small amount of fuel in it and turn the engine over very slowly against compression 
you should, if anything appears to seep down the side of the piston see if there is any leakage. If it does to any extent the piston is probably too small or the liner /piston possibly out of round and you may not be able to attain the compression required for starting. Sometimes squirting a small slug of neat oil into the port will help give a slightly better seal though it has to be said this is rather a last gasp hope - Regretably if the compression is not there no amount of flicking or modifying the fuel content will help bring it into life. - If that is the case and you feel a new piston is required then do say before you go ahead as you may be able to 'reclaim' the old one.

Hope this adds a little more - and I truly hope you are successful in getting it to run - I know just how you will feel if you do Thm:

Regards - Ramon


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## lensman57 (Apr 9, 2012)

Hi,

I was all set to build one of these engines as my first ic engine last year. I gave up after my extensive search failed to find the correct fuel. Either nobody stocked it or if they did it was not available through mail order. I was just not prepared to do a 400 miles round trip to pick up a gallon of the fuel. Reading all the replies perhaps it was blessing in disguise.

Regards,

A.G


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## mu38&Bg# (Apr 10, 2012)

I run many model diesels in my RC airplanes. It's only a little harder to learn to run compared to a glow engine.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXANCP&P=ML

It's easy enough to mix your own fuel, but straight ether is impossible to get in the US. Hobbyists who make their own model diesel fuel use John Deere starting fluid which, for mixing fuel after spraying it from the can, is all ether.

Greg


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## rklopp (Apr 10, 2012)

lensman57  said:
			
		

> Hi,
> 
> I was all set to build one of these engines as my first ic engine last year. I gave up after my extensive search failed to find the correct fuel. Either nobody stocked it or if they did it was not available through mail order. I was just not prepared to do a 400 miles round trip to pick up a gallon of the fuel. Reading all the replies perhaps it was blessing in disguise.
> 
> ...


I live in the US and have built and run several Diesels. I rolled my own fuel from hardware store kerosene, NAPA starting fluid, castor oil from the local motorcycle shop, and a dash of NAPA "cetane improver." The mix ratio I use is around 33%:33%:33%:1%. My Mills 1.3 engine fire right up. I am about ready to try starting three Gordon 0.1-cc Nanos I just built. I need to make some starter springs. 

To get the starting fluid out of the spray can, I bled off the propellant by spraying upside down. Then I knocked a hole in the can with a nail. All this was done outdoors far from ignition sources (but for the nail?!?!!).


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## Ramon (Apr 10, 2012)

Hi guys - it must be very frustrating not being able to source ether in volume. Here in the UK there are two fuel suppliers who still sell diesel fuels though only one of them sells through normal model shop outlets though these days it usually has to be ordered. The other does so at model shows only. Ether is (well was at last years Nats) certainly available from the latter but is no longer listed by the other supplier. 

Do you find that the starting fluid works as well as normal ether - volume for volume that is. I guess it's an expensive way to make fuel but if it's all you have then it's better than nothing. Might be worth dropping the content slightly and increasing the kero to economise a bit.

It's good to see there is some interest out there on building diesels - I hope to begin a new 5cc version of the Super Tigre G32 before too long if anyone is interested. The drawings are done but currently the workshop is in complete disarray with some improvements underway. Hopefully wont be that long though ;D

Regards - Ramon


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## mu38&Bg# (Apr 10, 2012)

Ramon  said:
			
		

> Do you find that the starting fluid works as well as normal ether - volume for volume that is. I guess it's an expensive way to make fuel but if it's all you have then it's better than nothing. Might be worth dropping the content slightly and increasing the kero to economise a bit.



No, not all brands of starting fluid work as well. You must look up the MSDS and determine how much ether is in the can. All off the shelf brands are mixed with hexane at various ratios. The trouble is some MSDS are not specific and offer a range like 30-70% Ether. This doesn't help. John Deere is not blended with hexane and the oil added to keep the cylinder walls from drying is small. Once all the gaseous propellant is driven off, it can be considered ether for mixing fuel. It's the only one I use.

Generally larger model diesels run well with reduced ether content. I run some of my engines without any ether at all, after warming the engine using normal fuel containing ether. Ether is essential for cold starting a model diesel and it reduces the required compression ratio for running as well as widens the range of tuning for the needle and compression.

Greg


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## Ramon (Apr 10, 2012)

Thanks for the informative response Greg

Have to say I have been fortunate not to have to go down this road so far, I stock up at our Nats each year but it makes you wonder how much longer it will be available for. 

Regarding running without ether - many years ago there was an article in Aeromodeller by a Robert Dulake on etherless fuels using cooking oil as a basis. Having just googled it it appears this has been well discussed as a viable proposition providing, as you say the initial start is carried out with ether based fuel. It certainly sounds a viable means to conserving ether based fuel.

Re Bob Dulake - I met him once at an early (for me) control line aerobatic competition where he was flying a very unusual model called the 'Swingliner' which he had developed. A strange, all sheet delta shaped planform with a side profile to match it if I remember right, it would fly on inordinately long lines compared to conventional models and which, by some clever bellcrank system, was relatively unaffected by the drag of them.
Oops, sorry for going OT

Regards - Ramon

PS Reading your post again this has just occurred to me .... what is your oil to kerosene ratio and once you have the engine warmed and switched over to etherless fuel are you able to start it again on such providing the engine has not cooled


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