Building the new Bushbaby SAFARI

[Oupa-G]

I see the hits have passed 62000 . Andy Cap thank you for honest reporting go back to previous page to realise how big the cockpit really is. A tall person has a different view and is very valuable. This is the first Safari and all suggestions are noted and I think the Komatipoort team will be reading every comment you have made. Regarding the hight of the seat there is enough place to fit the autopilot servo's , they can be moved further aft , I have already welded the tabs onto the airframe, but model 3 or 4 should be able to incorporate all these minor changes without any structural changes. I today have refuelled the Bosvark and am awaiting the piece of paper, Monty tells me it is just a formality now. My brain just works a bit faster even with the Oupa title. Andy when you are in the Fairest the flip is on and your boet is also welcome.

Cheers Oupa-G

[AndyCAP]

Thanks Oupa - thats very kind of you. i was really excited to experience first hand that you & your team are approaching the whole project from a practical perspective - thinking further than just your own requirements. This plane has come a LONG way from the original BB450

[doreen]

Hi Oupa

Nice work. Maybe you can use this. Installed the black/brown vacuum delay valve on the fuel pressure regulator and the MAP sensor, this sorts out the vacuum pulses at the short intakes and works fine for me. The tip of the injector is subjected to vacuum which will suck more fuel through it at idle than at WOT without a vacuum line on the regulator.

bmw

[Oupa-G]

Dear Doreen,

the pressure regulator gives 3.5 bar pressure in the common rail and the suction you are talking about you should tune with the software and the opening time on the injector that is the reason BMW uses the TPS for acceleration and not the manifold pressure. I have the one way valves in my system but I use it for my manifold pressure so that with a variable pitch prop you know what power settings you have thus RPM verses Man pressur=boost. When you are supercharging the engine the you can connect the the static side of the regulator to the turbo boost. Give me a tinkle and I can explain it better on the phone . We have no problems idling whatsoever.

Cheers Oupa-G

[Oupa-G]

Doreen,
Ystervark actually looked at the exact opening and closing time of the injector he built a special circuit to see this on the scope and calculates the injection timing from that. In theory you do not want to change the pressure there are the newer common rail system where the fuel pump pressure is regulated electronically but we are sticking to the KISS principle. At present our starting idling cold start, acceleration of the engine on sudden adding of power like a go round etc is sorted out as well as the altitude compensation. The three major factors are the prop, the exhaust system and the airframe. These factors influence the final tuning. Ystervark is busy doing the aerospace reliability testing which so far is going well. In the end the aim is safety.

Cheers Oupa-G

[ystervark7]

Doreen

Interesting idea you have there. Would you mind explaining a bit more about your setup: ECU, ect.

[doreen]

Ystervark7

In the photos of your built process it seems like you are not using a vacuum line on your fuel pressure regulator. All I wanted to point out was that I use the simple way by putting a vacuum line on the pressure regulator. As far as I understand it this is very important because if you subject your injector tip to different vacuum levels created by engine load, butterfly setting and other criteria it will have an affect on the amount of fuel sucked into the engine for the same opening time of the injectors if not corrected by some means. I am sure one can compensate for this with special lookup maps or calculations on a system, but in my opinion that is not simple for the DIY man.

[Boet]

Bosvarkie no 2 is safely in the fairest. Now just the wiring needs to be completed. Pics of the baffle seal system. ALL the air coming thru this cowling will cool something! Note how the baffle seals against the top cowling. That is how it should be. Doreen, I see no cooling baffeling on your engine installation?? On a lighter note. ALL those instruments have to go on one panel........ But the panel will be HEAVY? Jaaaaaa swaer.

[Oupa-G]

Boet that looks very very nice I'm sure that cooling will not be a problem . That silicone stuff is nice to work with. We will now give the project some vooma from this side.


Cheers Oupa-G

[Oupa-G]

Doreen
I looked at your manifold compensation I am using the same little one way valves ,once you have sucked the lower pressure are you releasing otherwise when you have to accelerate suddenly there is still a low pressure on the diaphragm of the pressure regulator and you will then have low fuel pressure , Have you measured the in line fuel pressure alteration with this set-up it normally should be stable at 3.5 bar. It would be interesting to hear your results. The idling is not easy to do we have managed to let our engine idle happily at 1000rpm with instant throttle response that is what you want at a go-round situation.


Cheers Oupa-G

[Oupa-G]

Boet during my lunch hour I quickly went to our airfield and had a look Bosvark II . Now you must know I look at the project with eyes that have been there before on top of it I look critically. All I can say is BEAUTIFUL stop. I'm envious because #2 of the production line has an advantage so maybe when say 10 or 12 Safari's have been built I will maybe build another one , the only thing I will do differently I will start with the paperwork first and then start building. Also had a chat with Aarti Panday of the engineering section of CAA we had a nice in depth discussion she has an Aeronautical Engineering degree from Wits univ and it is nice to see that we are getting such level of knowledge with people like that we can build up mutual respect.

Cheers Oupa-G

[doreen]

herewith

IMG.pdf

bmw

(87.63 KiB) Downloaded 229 times

[Oupa-G]

Doreen
thanks for the explanation . Regarding the CoG I have a nice Spreadsheet which I worked out the CoG and the engine position your welcome to use it, you will just have to fill in your moment arms. I know your busy time is coming up so the experimenting is for 2010. I agree with you that the playing and testing etc is a lot of fun. If we can be of help we will gladly help. The Bosvark's CoG is at it's most forward position with pilot seating . The seat and the fuel tanks etc moves the CoG aft . I do not know what your 650 does. Have a good holiday season. The Whisper is ready for extensive taxi testing I warned them about the vertical runaway condition that sometimes happens, they should be alert to this.

Cheers Oupa-G

[Trikenut]

This project is looking good! Excited to see this develop futher!

[Stephan van Tonder]

Has the ever elusive piece of paper not arrived yet?.