Back At It

I need to get caught up on all of the small things I've done over the last few weeks.  I haven't had a lot of time to tackle anything big, but I'm trying to remember that everything has to get done, and small tasks are still progress.

Since the humidity is going to start rising soon and it'll be at least a year before the engine fires up, I decided to pull out the engine dehydrator I built.  I never got the 3D printed valve I was using to be air tight, so I just pulled it out of the loop for now.  I may try to come up with a new valve design at some point, but for now I'm just keeping the dehydrator in the "closed loop" position all of the time.  The air pump pumps air into the oil dipstick tube, then pulls it out from the oil breather line and sends it through a canister of desiccant beads before sending it back to the air pump.  By keeping this a closed loop (vs pumping fresh air through the beads and not having a return line back to the pump), the desiccant will last a lot longer before I have to dry it out.  I will eventually need to get some rubber stoppers to connect the tubing to the engine, but since I don't have any and the dehydrator will stay in place for a long time, I just wrapped the tubing with plastic and taped it in place.  I also taped off the exhaust and air intake to minimize leakage of ambient air into the engine.  So far, the humidity level inside the engine is staying between 20-25%.  From what I've gathered, corrosion pretty much flatlines when humidity is below 40%, so if I keep the dehydrator running, I should be fairly safe to have the engine just sit for a while.

My propeller arrived this week!  This is the Sensenich ground adjustable prop.

There is a spacer that bolts to the prop flange of the engine, then the prop hub bolts on top of the spacer.  The prop blades insert into the hub and the pitch of each blade is set by inserting a pitch pin into the hub and turning each blade until they bump into the pin (each blade has a steel pin sticking out of the base).  It's a far simpler system than most ground adjustable designs, which usually require hours of fiddling with blades and protractors.

I temporarily mounted the spacer and base of the hub (with the spinner back plate), because I need to have a reference for where the front of the cowls need to rest.

Before I get to work on the cowls themselves, I needed to finish the hinge on the right side of the firewall.  The bottom two rivets on both left and right side hinges are buried right next to the engine mount and were next to impossible to buck, so I took the easy way out and used pop rivets there.

Now that I have the prop spacer and know the distance to the spinner back plate, I can finally get to work on the cowls.  I decided to start with something easy - I laid out and cut the oil dipstick door.  It's just a rough cut for now.  I won't finalize it until I'm done with everything else.

True to the internet stories of the last 20 years, Van's fiberglass is a disaster.  The finish isn't horrible, but the fit is amazingly bad.  They outsource the fiberglass parts, and I don't think the molds have ever been right.  I've never heard of anyone who didn't have to do a ton of work on all of the fiberglass parts.  It's so bad that it's pretty confusing about where to start.  I'm doing as much reading as I can.  I'll just have to jump in though.  At least I know that fiberglass can always be fixed.

Just putting the top and bottom cowls together, you can see how off everything is.  I think my first step will be to create a round jig the size of the spinner and get the round nose bowl the right size and shape.  That will guide how much I have to cut off at the sides to get the two pieces to nest together.  In all likelihood, there will be a lot of additive finishing that has to happen once I have it all fit.  Once I have the front fitting, then I'll cut and fit the top cowl to the fuselage, then fit the bottom cowl to both.  I have absolutely no idea what I'm doing.  Should be fun!