BMW Engined Aquilla

[Oddball]

I have also been running the engine to optimise it. To do this one needs to check the timing but there are no timing marks on the flywheel and bell housing so I had to first determine where Top Dead Centre is and mark it, then mark on the bell housing the degrees before TDC; so here are shots of the the engine running with the main and standby system timing

Timing1_Main.JPG (18.51 KiB) Viewed 2984 times

Timing2_SB.JPG (18.23 KiB) Viewed 2984 times

[Oddball]

Hey there Wargames, the Aquilla tank has two outlets at the bottom; one of these has one spigot/tube out that interconnects the two outlet sumps and the second outlet has two tubes - one for the interconnection and one for the feed to the engine. These tubes are about 6mm in diameter and this is just fine for a feed to a 582. With the BMW however, the engine is fuel injected and the pumps require a large intake (the pump inlet diameter is around 10mm). Fuel presure is raised and then regulated, with the excess fuel being returned to the tank. To deliver the required pressure and flow means that you need this large inlet, so to get that from the existing tank outlets I simply took all of the spigot outlets and delivered them to a manifold (3 x 6mm) which then has the correct outlet size to the pump inlet.
That's in theory.... of course in reality you also have to deal with filters which you cannot easily get at the right size and so now the manifold delivers out at 8mm to the fuel filter, then after the filter I had to make an adaptor from 8mm to 10mm pipe to connect to the pump again... sigh..

[Oupa-G]

Oddball congratulations with the installation. We made the timing marks on the alternator belt side when we checked the timing because once you have the prop on that side becomes the side that "bites". The other thing you must check is the dwell because you have the backup system on the big coil.which must be charged 2000 msecond the coil on plug about 1200 msecond . Also check the resistance on your plug wire because the plugs on the 1200 have resistance built in and these plugs are hard to get without resistance. You do not want resistance on the plug wire and also resistance on the plug the coil can then not dissipate the heat and coil damage can occur due to overheating.

Good luck

Cheers Oupa-G

[Oddball]

Thanks Oupa-G; I am busy with all of that now and optimising the system; so far she's running very well at low revs, but, having spoken to Otto, I realise that fine tjuning is required to 'go faster'! I'll report the progress here.
Jay

[bobthebuilder]

Hi Jay,

Do you have a date set for the test flight?

[Tailspin]

Jay was that you over the Freeway yesterday afternoon about 5ish ??
Sure looked like you from the ground - people in the car got a bit tense as i was looking up and not watching where i was driving

[Oddball]

It wasn't me! I've never flown over a freeway! You can't prove a thing! Er, which freeway?

I was around the R59 late yesterday afternoon if that is what you mean...

[Oddball]

Hey there Bobthebuilder,
Sorry about the late reply; we do not yet have a first flight date but I will post it when I know better. I am stuggling to get the engien to run properly at the moment- mostly because I lack the knowledge of exactly how to tune the engine- and because its a big sucker it chews the battery down with multiple starts... so I can experiment for about an hour and then the batteries are too low to get a start. Then I go home and scratch my head and surf the net for more information on how a fuel map should look- its a bit of a black art it seems.
Also having some problems with the oil pressure and temperature senders that I installed and have to work out why I am not getting the readings I expect- not an engine problem I think but more and sender problem.
Anyway, I am learnign more and more....

[ZULU1]

Jay, sorry to pick holes mate but I am not liking the position of the oil cooler. When Aiden and I did the HKS installation we mounted them on the wheel strut (support arm). In the wind and it alleviates stones in the unit. I installed two and removed one as it was overcooling. I use the Castrol 10W-60W synthetic and still get 5 bar at 100 degrees. This I still struggle to get incidentally and blank off half the cooler. I will send you the one I removed if you wish. Made by Cape Heat Exchangers and its a big fellow...

Keep going Paul

[Oddball]

Hey there Paul, advice is always good- especially from someone who has 'been there'. The oil cooler position is simply a tryout position. I have put temperature sensors in the inlet and outlet pipes so that we can see what is happening; and I have made the bracket in such a way that putting a new one in to lower the cooler into the air flow will be easy- or at least not too difficult!
We'll experiment and see....

[ZULU1]

Jay the HKS is dry sumped and the oil sender is on the tank itself on the top near the return line position. I am unsure where the BMW sites the oil sender, that position is critical. I discovered that the oil tank position was sensitive to engine performance and did the entire assembly on solid works. That way I could see the flying position and also the on ground position. It all works fine but now I still have an over cooling problem..even a hot KZN day and two up barely gets to 110degrees.

Keep going, I would like one of these on a Apollo jet as its cheaper than a 912 and sure i could find a few motors in Europe. When you get this right the containers will start arriving..

I have done many projects (work) and the norm is you add in things at the start and after trials you bin them, mark 2 is better and mark 3 is perfect, mark 4 is lighter and then they get cheaper..

Well done Jay and keep us updated.. Paul

[Oupa-G]

Jay I looked at your photo's maybe you should call me . We have two trikes with the oil cooler sorted out. I even have nice brackets to fit the oil cooler. We have given our engines more oil cooling capacity. Your oil pressure sender is in the oil cooler line ,that is an open system you will never get a reading. This engine has two oil pumps one pump is the high pressure system lubricating the bearings etc like any other engine. Then there is a second oil pump for cooling the cylinder heads. This oil circuit is thermostat controlled and only if the engine reaches 85C does the thermostat send oil through the cooler, and the thermostat is only fully open at 115C. The highest temp I have seen on the Bosvark was 103C and that was when the outside air temp was 39C . On the casing is the oil pressure switch you take your oil pressure there. The VDO sender should be on an extension pipe with a very small hole supplying the sender this buffers the pulsation and protects the mechanics in the sender unit. To start off I would use the map that we use on the Bosvark but to start off reduce the timing because you have the higher compression ratio engine. I have been through detonation "have the T-shirt" I will gladly help where I can. Ystervark7 has a lot of knowledge on this it also depends on the exhaust and the prop.


Cheers Oupa-G

[ZULU1]

Jay, this is the oil cooler location and mounting on my HKS. I have a matching unit with bracket. Sorry about the pic.

Keep going Paul

[ystervark7]

Jay, do not hesitate to phone if I can help with the tuning. I know it is a bit intimidating in the beginning. I also hope to visit you guys as soon as you are ready - just try and make it before the word cup otherwise the tickets are to expensive - or maybe they give them away for free if I go and watch a soccer match as well.

Keep up the good work!

[Air Hog]

Hi Oddball. What is happening. Are we going to see this at the Kroon Fly-in on the 29th of May?