Building the new Bushbaby SAFARI

[crashtestdummy]

Hi Oupa G

Would the r1200s engine also work it is higher output
or could the commpression be a problem

Engine


Motor Type
Air/oil cooled 2 cylinder, 4 stroke Boxer engine, one camshaft and four valves per cylinder, central compensation shaft

Bore x Stroke
101 x 73 mm

Displacement
1170 cc

Max Output
90 Kw / 122 bhp at 8,250 rpm

Max Torque
112 Nm / 82 ft/ lbs at 6,800 rpm

Compression Ratio
12.5/ 1

Mixture Control / Engine Management
Electronic intake pipe injection/digital engine management: BMW Engine Management, BMS-K with overrun fuel cut off, dual ignition


Thanks

Kallie Venter

[Oupa-G]

Kallie the Bosvark II has one of these engines in it and we are going to be very conservative tuning this engine. You may remember that I had detonation with the 100r engine . We will start of with a very conservative advance of the timing. These tuning figures will then be available for other users. Our data is and will be open source unlike BMW which keeps their figures secret. The first GS figures that we started on were read of a GS on a Dyno. At the moment our GS is running very conservative at 30 degrees before TDC those figures cannot be used on the RT. The GS has a better torque curve the GS has a higher lifting cam hence the lower max rpm . The rpm limit is no problem. I think we wont be able to use the higher rpm in the 100R and the 100RT

Cheers Oupa-G

[justin.schoeman]

Hi Oupa-G,

Although I don't have the time or money for another engine project at the moment, I am certainly keeping my eyes open. Current leader is definitely the BMW engine.

Although I am not working on it yet, I have spent a few hours day-dreaming on what I would like to do.

I would like to make the backup systems completely redundant - with different technologies. I was thinking of using carbs for fuel, or maybe a TBI (eg aerocarb, or ellison) as a backup for standard electronic injection.

For spark, I was considering a single electronic ignition (maybe eboxi?), and run the other ignition of a fixed timing briggs and stratton magneto. The magneto will be inhibitted at start (seeing as it will be heavily retarded), and only used once the engine is at an idle.

Do you have an idea how well the engine would perform with fixed timing? And single ignition (once the electronic ignition starts advancing, the magneto will be so far behind, it will have no real effect).

This system works well on a VW with a very limited rev range - I hope it will work on a BMW too.

Thanks!
Justin

[Oupa-G]

Justin I will have to put my mind to it. But our philosophy was 100% redundancy. So there are two 60-2 pick-ups one is the engines own and the other is on the flywheel two fuel pumps injectors plugs etc. The system the way it runs one system from the alternator supply and the other from the battery supply and the two systems are connected with a 20A circuit breaker. If you pull the circuit breaker either system runs independently, the alternator will keep on running till you run out of fuel. On the battery your engine will run till the battery is flat that should take at least two hours. On the Citation Jet if you go bat to emergency you have 30 min. So our redundancy is plenty.

Cheers Oupa-G

[crashtestdummy]

Thanks Oupa G

Will keep an eye out for a engine
and then bother futher

Keep up the incredibley good work and thanks for all your hard work

Kallie

[justin.schoeman]

Justin I will have to put my mind to it. But our philosophy was 100% redundancy. So there are two 60-2 pick-ups one is the engines own and the other is on the flywheel two fuel pumps injectors plugs etc. The system the way it runs one system from the alternator supply and the other from the battery supply and the two systems are connected with a 20A circuit breaker. If you pull the circuit breaker either system runs independently, the alternator will keep on running till you run out of fuel. On the battery your engine will run till the battery is flat that should take at least two hours. On the Citation Jet if you go bat to emergency you have 30 min. So our redundancy is plenty.

Cheers Oupa-G

Thanks Oupa-G. I had a good look at your redundancies when you were discussing it earlier in the build. I really like what you have done there. It is certainly the best fully electronic installations I have seen. Most other installations have what can best be called 'redundancy' (with the quotes), duplicating big chunks of the system, but have only one of the common failure points (pumps and senders).

The only system I have seen with a higher level of redundancy is the Revmaster, which actually has two complete alternators too!

The only reason I am contemplating a fixed ignition is that I am rather old-school, and really like simple solutions. Hopefully I will find an engine sometime, and do some playing myself .

[Oupa-G]

Justin go for it any new thought is welcome, at this stage I'm happy with the level of redundancy. If you really want to go fully redundant you must follow the FAR25 rules , two engines two pilots etc. With a single engine aircraft one must draw the line and that is where we have drawn the line with the Eboxi system. All I can say it is flying and it works. But if you have a mechanical problem and something breaks in the engine all the redundancy helps nothing and you must still possess forced landing abilities. My new prop has arrived and it is a beauti , luckily it came before the weekend. So some more exciting flying.

I also see that the amount of visits have quietly slipped past 80,000 visits. I've just unpacked the new prop also had the damaged prop trimmed by Pieter maybe it can serve for some racer or a wall ornament, enjoy the pics.



Cheers Oupa-G

[Oupa-G]

The new prop is on it is now a Pprop 74X60 I quickly ran it without spinner , the spinner needs adjusting a bit to fit the new prop.

The run on the runway gave me 6800rpm and the prop is very smooth. Will fly the Bosvark this evening and will report back later.



Cheers Oupa-G

[Oupa-G]

well the news is out it is now all happening at different power settings but the speed stays 100mph beyond that magic figure one must either clean up the airframe or put in more power or except the 100mph figure . I'm going to except the 100mph, the Bosvark is now really a get in press the button type of plane. Now that the static is sorted I approach at 55mph and as soon as I land I dump the flaperon that gives me more tail authority. I find her to be an extremely easy to fly aircraft and very docile and very stable. This morning it was 33 C OAT and the engine #'s and temp's stay normal. So now I will start with the fuel consumption. I'm busy making a fuel dip stick as per recipe of Nico ( Dusty Eagle).



Cheers Oupa-G

[Oupa-G]

Of the "hot and high" tests the Bosvark definitely passed the "hot" test . This engine just runs nice cool temps even if the day today ended with 38C. So Boet the cowling and the ducting and the baffling works. Will be calibrating the fuel tanks and fuel dipstick to-morrow. Took a nice piece of Ash wood did the classical steaming of the wood and bent it to fit the tank. With my soldering iron I burnt the year-rings so that the fuel level shows better. So to morrow I will do the 5 litre increment markings.

I'm enjoying the Bosvark.


Cheers Oupa-G

[Oupa-G]

The BMW Whisper has flown it was not even a vertical taxi but a real flight, because all the paperwork was in place. Everything functioned and we will now tune the engine to the airframe prop combination. Looking forward to flying to-morrow have calibrated the fuel tank to the dipstick.

Cheers Oupa-G

[Oupa-G]

Back from Grootfontein first calibrated the dipstick and then flew the aeroplane and I must say she is growing on me. The static source is a great success after the compass swing the airdata computer is working well so now I can check the ASI against the GPS speed and wind vector at this stage I feel very comfortable with the approach speed of 50 mph with some flaperon on. It makes for nice landings and now that the static is accurate the next test will be the stalling and the calibration of the AoA(angle of attack) indicator .
I'm showing a photo of Bobby of Morning Star fame holding the Landing Compass while we were swinging the compass luckily I can sign that out in the logbook. An accurate compass swing is imperative for the airdata computer and the GPS to give an accurate wind factor reading. We are living in wonderful times, the electronics are so sophisticated and the Bosvark's instrumentation is more modern then the PC12's instrumentation that I fly.

I'm also showing a screen shot of the screen in flight I'm posting the screen photo first so that my commentary can be related to the screen photo.
Top left corner GPS speed 85mph next to it to the right direct headwind of 9mph with an airspeed of 94mph at 5800rpm(lower right corner)

On the engine sub panel Oil temp in the sump the round dial 78C Oil temp into radiator 89C and outlet 77C the thermostat only fully opens at 115C So the amount of oil going through the radiator at this stage is well within the capacity and there is lots of reserve. This was evident when I flew at 38C and 41C temps last weekend unluckily the screen shots are no good because of the turbulence, but the highest temp I saw was the radiator inlet at 105C.
The cyl head temp are 79 and 77C remember these heads are oil cooled.
EGT's around 720C and I would like to see them around 800C at these power settings, that will be tuned.

The gearbox temp is 53C nice and cool . That spells long levity.
Overhead Table Mountain is the Data of Morning Star and all you do is point your nose in that direction and "Voila" you arrive at the field it tells you your time to go etc. this is better than "Rooi Jelly"

That is all for today to-morrow morning I'm leaving for Upington I'm driving because the Baron is being serviced to the finest detail. She is getting her loving 30 year service and we give attention to all the minor detail which is not part of an MPI inspection but part of love and care. I've swapped my Cruiser for a later model still a 100vx the 200 is to fancy. So I'm looking forward to the drive. My net-book will be coming along so I can follow the site . The wind is pumping again and I hope for the cyclist in the Argus to-morrow that it will sub-side.


Cheers Oupa-G

[Oupa-G]

Tonight made leather seals inside the fuel caps. They have a nasty habit of binding , hope this will solve the problem. Leather is a wonderful material and work well with fuel. Had the same problem with my Trike tank and I solved that problem also with leather.

Cheers Oupa-G

[Oupa-G]

Tested the fuel dipstick in Loeriesfontein on Grote's Safari III and it worked well. Boet has copied the markings. Thanks to the owner of the Camo Bushbaby for the inspiration, also known as Dusty Eagle. I love the exchange of ideas.

Cheers Oupa-G

[Oupa-G]

Back from Upington to-morrow I will adjust and calibrate the AoA indicator and the fuel flow . Some serious fine tuning to follow. The Whisper with the BMW engine has flown again and is now also due for fine tuning . Luckily the map from the Bosvark can easily be transferred to the Whisper. Worked all week must now seriously play over the weekend and luckily there is an extra day on Monday.

Cheers Oupa-G