It's safe to say that any flying machine is a collection of parts that are strategically placed and assembled to enable one to fly.
Although this is true, it's the little things that get accomplished over the course of a building project that make the difference in not only getting the plane built, but improves the overall quality and performance of the end product. It also contributes to the philosophy I spoke of last August on my blog: ( a-little-here-a-little-there).
Today I decided to pull out the Corvair heads and have a closer look at them.
You might recall that these heads are 110hp versions from a 1966 car. They are just as I received them from the seller - not filthy but certainly not clean either!
Any engine that is more than 50 years old is bound to be grimy. Air cooled engines like the Corvair have many, many cooling holes factory cast in between the head fins. Being small, they trap everything. Not good as the GM engineers counted on these being clear for optimum cooling. What the GM engineers didn't consider is that casting aluminum or other metals sometimes leaves "flash" where the moulding halves join up during the casting process. Either it was considered to costly to remove the flash or maybe they decided it was good enough. What I have experienced however is the massive range of acceptable "flash" tolerances - some heads have so much the cooling holes are almost closed over. With a small amount of dirt in there, they are effectively closed to cooling air.
Here is a look at the cleaner of the two heads. I've put a lightbulb behind to ease the viewing:
As you can see, the cooling holes are many and this head seems quite good. Some minor flash to clean up but generally good.
The 2nd head, despite being from the same casting lot as the first is terrible! I could only find one hole that was clear and even then it was almost closed over from flash:
Took an hour with a combination of small files and old steak-knives, but I managed to clean out the majority of the gunk from the cooling holes.
Both heads really do need a good pressure wash before I'll be able to remove all the flashing, but this was a good start. Removing the flashing is very important and goes a long way to improving cooling of the heads.
It's these little things that take time, but make a world of difference and counts towards the goal. Along those same lines, my father Jim and I have been working on an important submission regarding my mentor Barry. I don't want to say much yet but it's a little thing that also counts for something. Stay tuned for more on this shortly.
Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.