AMP-1 Rocket Engine

To accelerate this project's development, it is time to start tackling other construction problems. The first major issue is to get the Data Acquisition System figured out. This has been a headache for a long while as the DAQ board being used, a LabJack U3, doesn't seem to want to read the values from the pressure transducer. The thermocouples are a whole other problem that still needs a solution as well. To find whether or not the board was cooperating with the hardware being used, the load cell was set up on the bench and hooked up to a 12V power supply. I had not realized until measuring the voltages that the load cell outputs a very small voltage that would need to amplified and scaled to properly measure the amount of force the load cell is under. Applying a small amount of clamping force in the vise on the load cell showed that it outputted voltages in the mV not V. The values being read were between 0.000V and 0.017V. The next logical step would be to purchase an amplifi...

Utilizing the same procedure as the top plate, the 3/8-18 NPT port was threaded into the bottom plate and the whole lot was dry fit together. Some more welding practice is going to be done in the near future to prep for welding the fuel tank. The tank needs to be near perfect so there is marginal room for error. The series of pictures seem to dictate that tapping was done on the mill table. It was not. The tap was squared up with the mill spindle and the first few threads were started to get them straight. The rest of the tapping was done in the bench vise with wood spacers to protect the plate.

Some more work was done on finishing up the fuel tank parts in preparation to weld the whole lot together. The first of the two tapped ports was done with a 1/4 NPT tap. From the pictures below, it is evident that I need to find a better way to tap holes 1/4 NPT and larger. It is definitely not good to crank on the tap while clamped to the mill table. Also clamping to the bench was not happening either. The only way I could get the plate to stay was with some wood buffers in the bench vise. Furthermore, the next port I won't tap to completion because I am not sure how much warping will be happening when this is all welded together. I will probably start the tap and go a decent way down but finish it after the welding is complete.

Some chamfers were cut into the stay holes so there is ample area to fill with the weld and make a strong bond between the plate and stay rod.

To properly drill the holes for the stays that will run the full length of the tank, a centering pin needed to be made to line up the two end plates as concentric as possible and then clamp the entire assembly down to the mill/drill table. The pin was made on the lathe to accept the already center hole used during the O.D. turning operation. The series of steps below thoroughly illustrates the entire process done to finish drilling these necessary holes.

After getting the procedure down from the first end plate, the second and final one was machined much faster. First off, some tweaking needed to be done to the fixture in the lathe as the shaft O.D. was slightly oversize from most likely a burr. That was fixed and the blank was turned to its final O.D. and the chamfer was added. Both parts came out excellent and will be going to the next step which is drilling holes for the stays.

This evening, the final O.D. of the top end plate was turned on the lathe and the 1/8" chamfer as well. I was pretty happy with the fit of the plate into the barrel and now the fitting hole needs to be drilled and tapped along with the holes for the stays. While cutting the chamfer, it was noticed that the part was resonating causing a poor surface finish. Fixing it was as simple as cutting down the RPMs.