Friday, 8 July 2011
Starting to look like a test stand.
Yesterday I finished a task that i wasn't particularly looking forward to which is mount the load cell and motor on the test stand. It is tricky because you need to make a lot of holes in many plates that all need to line up. When putting everything together the bolts that hold the engine on were a bit tight but with some persuasion the went in. Hopefully next time will be more accurate as i learnt a few tricks for making everything fit better. Also there are only two bolts holding the threaded rod in the photo as the other 4 are not installed.
I also installed the injectors (designed for barbecues) i bought earlier in the week. At the store the chap said that they has a 0.35mm orifice but maybe he as talking about radius because they are at least 0.7mm in diameter and i think they may be a bit bigger (i only had a 0.7mm drill bit). I am a bit annoyed becasue i will not have to plug them with something and drill them out again. The reason I went with injector "jets" is that drilling a hole smaller than about 1mm is really really hard and you go through alot of bits. If your unlucky enough to break them off inside the thing your drilling into then you have to start from scratch. I will use lead to plug them so it shouldn't be too bad. Also the jets are not conical at their exit so i have to make them. I thought it would be interesting to try the engine with straight jets.
The other day i went to a auto gas store to get a gas certificate for my LPG car and i got talking with the mechanic. He let me have a rummage through their dumpster and i got a few working solenoid valves. Unfortunately they are only rated to 2.5MPa but i am hoping they ill have a relatively high safety factor. They won work on this engine but the next one will operate at a lower pressure and would be perfect for a flight vehicle because they are really light.
Also i found out that the wire that i thought was silver is actually oxygen free copper. Although i dont see how copper could be silver in collor Ariel insists.... It would explain the lack of reactivity.