I would appreciate some feedback and advice on what to look out for when buying a used BB with a 912 UL.
The potential known pitfalls, important SB's and AD's you guys know of which are considered mandatory, or any other important info.
Thank you kindly.
What to look out for when buying a Bushbaby?
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CloudDancer
- Pre flight checks done
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Building my own Bush Baby has opened my eyes to quite a lot of things
Firstly the airframe is very well made and incredibly strong so you shouldn't have any real problems there. Obviously this all depends on age and use, i.e. a training aircraft is going to have hammered suspension
Look on http://www.saplanes.co.za at the Technical Support section and the service bulletins
Have a very carefull look at the controls, if neccessary get them to take the seats out and have a look at all the pushrods. Your central column with the two joysticks move left and right and forward and back. The left and right movement pushes a very short little pushrod made up of a male and a female rod end (they have flexible bearings that can rotate pretty much like chameleon eyes). The rotating of the bearings on this pushrod gives you the full range of motion for up to down elevator. This should be 40deg max. Now pushing the joystick all the way forward and pulling all the way back you still must have a slight movement on the pushrod. The pushrod must not take any twisting strain. This pushrod must be locked with a locknut, i.e. the motion should not be taken up by movement on the threads but rather on the bearings.. Check how much up and down elevator you are getting, should be a min of 25deg up and 15 deg down. Up is more important than down.
Have a look at all the pushrods and make sure they are screwed into the rod ends quite deeply. If you see 10mm of thread then they are screwed out too far. The big 25 mm push rod going up tp the tail has two cone shaped ends and two male rod-ends screwed into them. These must be screwed in all the way and NOT used to adjust length of the pushrod. The other side is visible under the hor. stab. on the lefthand side. Here you will see the elevator horn.
Make sure all the bolts have nyloc nuts and there is at least 3 threads protruding past the nut.
Look at the crimping on the rudder cables. This is both at the pedal and at the rudder end. Check the bulletin on the website
There should be no movement on the control columns other than those allowed by the movement of the various bearings.
Get them to take you for a test flight or have someone you trust go for the flight to check that the plane flies hands off. We have experience where the plane was supplied and you could not fly it hands off. If you let the stick go the plane rolled to the left.
Check the serial number of the engine and then go to the rotax websites and check what service bulletins are required to been performed on the motor. Check the log book for these bulletins/updates.
Press your finger into the fabric. It should be flexible enough to make a dent and then return to a flat surface. If you hear any form of cracking then they used the wrong paint and dont buy it.
Check the build quality, especially if they were fully home built. Boet's planes are very well built but you never know with someone who built it at home on their own. Check that they haven't modified the airframe at all, there is no welds or cracks etc. Ask them for the build log. Hopefully they kept an accurate record. If possible get Boet to check it out before buying.
Firstly the airframe is very well made and incredibly strong so you shouldn't have any real problems there. Obviously this all depends on age and use, i.e. a training aircraft is going to have hammered suspension
Look on http://www.saplanes.co.za at the Technical Support section and the service bulletins
Have a very carefull look at the controls, if neccessary get them to take the seats out and have a look at all the pushrods. Your central column with the two joysticks move left and right and forward and back. The left and right movement pushes a very short little pushrod made up of a male and a female rod end (they have flexible bearings that can rotate pretty much like chameleon eyes). The rotating of the bearings on this pushrod gives you the full range of motion for up to down elevator. This should be 40deg max. Now pushing the joystick all the way forward and pulling all the way back you still must have a slight movement on the pushrod. The pushrod must not take any twisting strain. This pushrod must be locked with a locknut, i.e. the motion should not be taken up by movement on the threads but rather on the bearings.. Check how much up and down elevator you are getting, should be a min of 25deg up and 15 deg down. Up is more important than down.
Have a look at all the pushrods and make sure they are screwed into the rod ends quite deeply. If you see 10mm of thread then they are screwed out too far. The big 25 mm push rod going up tp the tail has two cone shaped ends and two male rod-ends screwed into them. These must be screwed in all the way and NOT used to adjust length of the pushrod. The other side is visible under the hor. stab. on the lefthand side. Here you will see the elevator horn.
Make sure all the bolts have nyloc nuts and there is at least 3 threads protruding past the nut.
Look at the crimping on the rudder cables. This is both at the pedal and at the rudder end. Check the bulletin on the website
There should be no movement on the control columns other than those allowed by the movement of the various bearings.
Get them to take you for a test flight or have someone you trust go for the flight to check that the plane flies hands off. We have experience where the plane was supplied and you could not fly it hands off. If you let the stick go the plane rolled to the left.
Check the serial number of the engine and then go to the rotax websites and check what service bulletins are required to been performed on the motor. Check the log book for these bulletins/updates.
Press your finger into the fabric. It should be flexible enough to make a dent and then return to a flat surface. If you hear any form of cracking then they used the wrong paint and dont buy it.
Check the build quality, especially if they were fully home built. Boet's planes are very well built but you never know with someone who built it at home on their own. Check that they haven't modified the airframe at all, there is no welds or cracks etc. Ask them for the build log. Hopefully they kept an accurate record. If possible get Boet to check it out before buying.
Greg Perkins
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gertcoetzee
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Thunderboy
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I don't think Boet is the only good BB builder in South Africa - there are a lot of good ones and a lot of bad ones. I have heard of some issues with welds not being good e.g. tack welds only being done on the airframe. After this being picked up by the AP, the response from Monty was to get a local TiG welder to "fix" it. So the quality of the kit itself does seem to vary and does not only depend on the builder. There are proper ways to test the skins - an AP will know how.
Best bet is to get someone who has built a Bushbaby well before to take a look at it, because, as Morph says, you get to know the aeroplane when you have built one yourself.
Best bet is to get someone who has built a Bushbaby well before to take a look at it, because, as Morph says, you get to know the aeroplane when you have built one yourself.
Baie meer ervaring as die gemiddelde ou wat al een of 2 goeie aeries gebou het IMHO.
I have seen a couple of BBs which had the older black bungee fitted and later suffered undercarriage damage.
This damage was eventually caused because once the low quality black bungee started to stretch prematurely, the guys were simply pulling on a few extra turns instead of replacing the bungee. The aircraft sat up again on the suspension but there was not enough stretch in the bungee anymore to absorb the landing forces.
At the next "firm" landing the forces are transmitted into the fuselage causing bent axels, bends where the main gear bolts to the fuselage and bows where the bungees wrap around the gear legs.
So look for bent axels shown by brake assemblies that do not seem to be in the middle of the brake drum, bent fuselage/gear mounts by a slack section of fabric there and the bend where the bungees go around the gear legs.
To inspect inside the wing, take the tip off and have a good look with a torch, this will give you a good idea of the build quality.
Get other Bushbaby owner/builders to have a look at the plane as well.
Also note the serial number (stamped on a plate welded to the frame on the inside above the door) and phone Monty at Kitplanes for Africa, he will probably know the build history.
This damage was eventually caused because once the low quality black bungee started to stretch prematurely, the guys were simply pulling on a few extra turns instead of replacing the bungee. The aircraft sat up again on the suspension but there was not enough stretch in the bungee anymore to absorb the landing forces.
At the next "firm" landing the forces are transmitted into the fuselage causing bent axels, bends where the main gear bolts to the fuselage and bows where the bungees wrap around the gear legs.
So look for bent axels shown by brake assemblies that do not seem to be in the middle of the brake drum, bent fuselage/gear mounts by a slack section of fabric there and the bend where the bungees go around the gear legs.
To inspect inside the wing, take the tip off and have a good look with a torch, this will give you a good idea of the build quality.
Get other Bushbaby owner/builders to have a look at the plane as well.
Also note the serial number (stamped on a plate welded to the frame on the inside above the door) and phone Monty at Kitplanes for Africa, he will probably know the build history.
Nottaquitta
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CloudDancer
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Willie
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The under carriage on the older models are paper thin tubing. 
We suffered a lot of damage due to that. Make sure it is upgraded.
I have been flying taildragers for many years but the Bushbaby is not easy.
We suffered a lot of damage due to that. Make sure it is upgraded.I have been flying taildragers for many years but the Bushbaby is not easy.
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