Re: BMP-1 IFV - Soviet army, Afghanistan 1980s - Build
Posted: Mon Nov 12, 2018 12:10 am
After study of the 3D road wheels, I determined they could be made to use ball bearings inside, whether by design or luck, I do not know. They seemed to have been designed to hold a flanged Ball bearing on each sides, of the following size; 3mm interior hole, 2.5mm wide and 7mm high. Therefore, 24 of them are needed, they are available from China for a few dollars for a lot of 10. This also means an inexpensive Flat head Lock Cotter Clevis M3 Pin can be used as shaft, also from China. No ball bearing with M4 center could fit the road wheel so this is why M3 is the best alternative.
After the head of the pin has been filed a bit, the provided 3D hub caps fit perfectly on the road wheel..
These are the parts required for the suspension arm. I previously made the shaft hole of the arm 4mm wide. This is perfect for a 4mm aluminum tube to be inserted inside, into which the M3 (3x16mm) shaft will enter for a tight fit.
After the 4mm aluminum tube is pressed inside the arm, a hole is made for a M1.8 metal bolt to lock the whole thing in place. The bolt will run through the hole in the 3mm shaft pin.
The road wheel is installed on the suspension arm, and is very solid and runs on ball bearings... What more can be asked.
To install the suspension arms on the hull, it seemed logical to somehow use the hole that is drilled at a specific location. Not sure if it was planned but there is enough room for a (6mm interior size) washer to be inserted in the slot in the plasticard, which happens to be correctly located in front of the hole, then a bolt can be used as a retaining device against the washer. Again, the hole for the bolt was not standard so I drilled it to fit a standard M3 screw.
Torsions bars are connected to the arms.
The two prototypes work perfectly and the suspension is really solid and smooth, it runs on Leopard 2 bars. I thinned them a bit to make them more flexible. Great, now I have 10 more to do in similar fashion and the suspension will be finished. There are likely many ways to do the suspension, this is one of them and it seems to work well and use inexpensive items.
Regards, Louis
After the head of the pin has been filed a bit, the provided 3D hub caps fit perfectly on the road wheel..
These are the parts required for the suspension arm. I previously made the shaft hole of the arm 4mm wide. This is perfect for a 4mm aluminum tube to be inserted inside, into which the M3 (3x16mm) shaft will enter for a tight fit.
After the 4mm aluminum tube is pressed inside the arm, a hole is made for a M1.8 metal bolt to lock the whole thing in place. The bolt will run through the hole in the 3mm shaft pin.
The road wheel is installed on the suspension arm, and is very solid and runs on ball bearings... What more can be asked.
To install the suspension arms on the hull, it seemed logical to somehow use the hole that is drilled at a specific location. Not sure if it was planned but there is enough room for a (6mm interior size) washer to be inserted in the slot in the plasticard, which happens to be correctly located in front of the hole, then a bolt can be used as a retaining device against the washer. Again, the hole for the bolt was not standard so I drilled it to fit a standard M3 screw.
Torsions bars are connected to the arms.
The two prototypes work perfectly and the suspension is really solid and smooth, it runs on Leopard 2 bars. I thinned them a bit to make them more flexible. Great, now I have 10 more to do in similar fashion and the suspension will be finished. There are likely many ways to do the suspension, this is one of them and it seems to work well and use inexpensive items.
Regards, Louis