Building the new Bushbaby SAFARI

[Oupa-G]

Michiel Dankie die Jabi se pype le hier maar my focus is op die Bosvark. Sodra dit verby is sal my focus verander.

Cheers Oupa-G

[Boet]

First sparrows this morning started covering MY wings, and finished by late afternoon. Once Oupa gets to fly the Bos-ot, I foresee his trike gathering LOTS of dust!!

[RV4ker]

Awesome article on said BOSVARK in Pop mechanics this month....

MOOI MANNE

[Oupa-G]

Today the Burger newspaper got hold of the Pop Mech story and promptly sent their reporter. So the guys that are in the Burger distribution area you can read the latest distorted news on the Bosvark . The Pop Mech did a lot of trouble writing a correct article my experience with newspapers is not so good because they don't let you proofread anything published. Meanwhile I'm fitting temp probes everywhere ,the Voyager allows me apart from the normal probes 12 xtra channels.

Ran the engine on the lawn today up to 5200 rpm an the exhaust is awsome . This weekend we are going to tune the 3D program. Then some finishing touches and the Bosvark must go for the fast taxi trials.

Cheers Oupa-G

[Oupa-G]

I see it is only 14 hits short of 25000 . The amount of hits still makes me humble.I will try to keep it interesting .

The whole test phase with all the data is going to exciting.

Cheers Oupa-G

[ystervark7]

Ok I hear what you say but the scetch shows both systems reading TPS Redundant just doesn't read air temp. Then I'm trying to understand how the spark side is run - I assume you are running something like coilpacks fired by the management - not the usual 'magneto' system as per airplanes normally?. So each system can fire the coilpacks seperately? - can you have both ECU's 'live' to the spark side? - probably not. Unless the one system runs the one sparkplug and coilpack and the other system runs the other spark plug meaning they are always 'on' and you have the redundant 'mag' setup then which is what I think I'm seeing in the sketch.
Then Each ECU has a fully redundant Fuel system to itself - meaning you can shouldn't run them together for the fuelling side as it will then double the fuelling up?

You don't use manifold pressure at all for tuning or do you? TPS is great but doesn't actually show load on the motor the same way. I prefer to tune car engines using both but of course it's slightly different for airplane engines. I assume you also use variable timing seeing it is available in an EFI system as opposed to running 'locked' timing. Makes for easier starting for a start..
Yes I know AGM batteries - use one in my landcruiser to run the fridge..

Stephan

I will try and clarify one or 2 things. Each cylinder have 2 plugs and yes you do have 2 coil packs (the BMW 1200 have 2 plugs standard). Both plugs are fired but the backup system fires about three degrees later than the main one. (the normal ECU also fires both plugs but I understand that they only fire the main plugs at high revs - maybe I should check it some time)

Yes we do vary the timing. We start at about TDC and advance to about 36 degrees BTDC at about 3600 RPM. We normally advance a bit less close to peak revs (35 degrees @ 7000 RPM) for safety. The fuel is cut completely if the revs is above redline, normally set to 7200RPM, so you have no danger of over revving.

Both systems have a TPS connected in the drawing but the backup system can run without the TPS (the main system can not). Installing 2 TPS's is quite expensive and you can either run only the main system on the TPS or run both from the same TPS. Running without the TPS you are limited to a 2D map and you lose the ability to accelerate suddenly but it will get you home.

Both systems should be able to run without the temperature sensors in case the sensors or wires break during flight (maximum temperature is assumed when a disconnection is detected). You will not be able to (or it will be very difficult to) start without the temperature sensor when the engine is cold.

I do tend to agree with you the more I work on tuning the engine that it is better to use a pressure sensor (MAP) rather than a TPS. I might try it some day. The software is already written and tested on a 912 (the "other engine we do not want to mention"). We are worried about the pulsation of the 2 cylinder but I do have a trick or 2 up my sleeve.

Note: The backup system is not exactly the same as the main system. You gain more robustness but you lose some performance.

[Oupa-G]

Thank you Ystervark7 for explaining the system so well. I see we have passed the 25000 mark, at the moment I'm clearing all the little loose ends I'm showing the brackets for the coil on plugs that are underneath and are part of the secondary system . On the one side you see the breather filter and on the oposite side the blanking plate for the area where we harvested the camshaft sensor. The blue plate holds in place a plug with an o-ring and on the last picture I show the sender unit already previously mentioned. That is the sender unit for system #2. On the first two pictures note the close baffling now hel in place with springs. The air passing can only pass via and around the cyl head and cylinders. Also note the purple nail varnish is put on anything that has been double checked. We are now aiming for the finishing act. Enjoy the pics

Oupa-G

[MYR]

Hi Oupa-G !
You have already spoken of the consumption of the 3 trikes, but what consumption do you expect with the Safari ?
Regards.

[Oupa-G]

Dear Myr

You are asking a difficult question. We know that a well tuned BMW uses 235g/Kw/hrs. The engine set-up is the same as we have been running on the Trikes . When we go on long trips we use 12.7 lit/hrs on a fast cruise that is 65mph on the trikes . We also have fuel injected a Rotax 912S and flying in formation with the two BMW trikes the fuel consumption is identical. In our group there is a Trike with a 912S with Bing carburettors and cruising with the group this trike uses 15 l/hrs. The consumption on the Safari I expect to be anywhere from 13 to 16 l/hrs this will very much depend on how fast you cruise and it is a function of how many Kw you are pulling from the engine . All I know there are two thing I only believe when I have flown an air craft and that is speed an fuel consumption.
If I loiter with my Trike around 45mph I'm using 8l/h. All I can tell is that I will publish honest figures when it comes to test flying time.

I hope this answers your question

Cheers Oupa-G

[Wargames]

Hi Oupa-G,

My wife found this on the net. Lekker Lekker!! Our own superstars right here in the cape!

http://www.dieburger.com/Stories/News/19.0.1492250640.aspx

[grostek]

Oupa G,

You and every member of your team is a STAR .
Each and everyone has brought his own talent and build quality into the complete Bosvark.
To motivate such a team is another story entirely, and I can only salute you all for your dedication,perserverence and motivation.

Then, Oupa G for you to find and make time to update this thread every evening is truly awe inspiring.

This is Homebuilding at its best and the CAA would do well to take note of these vendevours, because each and every actual and potential homebuilder in South Africa brings much the same dedication and responsible outlook to their own projects.

Sterkte en voorspoed,

Kind regards,

Gunter Rostek

[Boet]

Bos-Ot no 2 now only need all the "loose parts" around the engine, and some instruments, etc, then it will be a comlete aircraft too. can hardly wait. My Explorer will be getting Oupa`s old 1100cc from his trike, to be made into a flying test-bed. As it will be economical to fly, I will be a little less "out of circulation".

Gunther, thanks for your kind words, I can asure you guys, it is an honour to be part of this team!!

[Oupa-G]

Thanks everybody for the kind words I'm just trying my best. I have the ability to use every minute and it helps not watching TV I find TV not very inspiring except for a few programs and then there is the wonderful machine that can record. In the photo's you will see Otto tuning the engine and Eboxi programs. I caught him tuning with the prop spinning. With all the probes installed I can't get the engine to overheat. Of course we can't pull any power in the workshop. I have started withe silicone baffle sealing. This works out well and the taxi tests are coming closer. Installed are the piggyback Eboxi's . Both boxes have started the engine no problem and we will now finish the wiring for the backup system we chose to do that wiring in two steps as not to build in problems that can so easily happen. From the header tank point of view everything is working well the header tank at the moment is breathing to atmosphere and in the final setup the breather will breath back to tank. Breathing the system is absolutely essential. I'm calling it a day tonight and will finish the baffling to-morrow subject to the Red Cross calling me. Enjoy the photo's.


Cheers Oupa-G

[Oupa-G]

Sorry I lost the photo's a typical Windows problem had to restart computer so here follows the rest of the photies

Cheers Oupa-G

[Oupa-G]

Another day of intense working finished the seal around the baffles to make sure that none of the precious air escapes without doing some heat absorption. The material is high grade silicone sheeting cut to suitably sized strip and riveted in place. The material is heat as well as oil resistant. Also the sheeting is soft enough that it will mold and shape under the air pressure.

The oil cooler air box has now received the piping. I reckon one more day of tidying the wiring from all the probes and all the work firewall forward is completed. At least I can say that that side of the building is finished before the end of April. The panel and the connecting of the radio's transponder etc. will take some carefull thinking as well as time. Some pictures enclosed of the baffle seals.

Enjoy the photo's

Cheers Oupa-G