Stjohn's RV-7

5 hours.

This is for Monday, Sept 2.

I really need to do these log entries directly after I do the work.   Makes for an easier time remembering what went on.   Without the EFIS in place and having wires everywhere, I wanted to stay out of the cockpit as much as possible.  I tightened up the canopy strut attach points, and completed the left aft spar bolt.  Yeah, I forgot to put the nut and cotter pin on there earlier, when we mounted the wings.  I guess I was so focused on getting that bolt in there while I had help, I didn’t think much about it afterwards.   I’m really surprised I didn’t notice it when I put the flaps on.   It would have been way easier that way.   Every time I go to some region of the plane,  I keep finding things to do, but the items are quick tasks and detail work.   I also installed a couple more heat shields on the exhaust near the throttle and mixture cables, plus I torqued down the spark plugs and the plug wire attach nuts.

No fuel smell in the cockpit, so it appears my fixes to the fuel lines and boost pump have worked, which is nice.  I also have no leaks in my fuel tanks, as far as I know, with the paltry gallon of gas in each one.

I reworked the tailwheel chains again, because last time, I had the steering link on backwards.   This meant that I cut the chains about 3/4″ too short and had to replace them.  Worked out OK, except for the fact that I overtorqued the nut on the tailwheel fork.  I might have to order a new one, which would suck, but what’s done is done.  But other than that, the tailwheel is good to go.

I should get the EFIS back this Friday, and should be able to reinstall it Saturday or Sunday.

Sunday I had more instruction with Mickey down at KTOA.  I keep making noob mistakes like trying to steer the plane with the stick, flaring too high, landing too slow, and flubbing radio calls, but considering the amount of hours I have, I actually am a noob.  I now have something like 8 hours of tailwheel time, which means I’ll crack the 100-hour total time mark during my next lesson.  I expect to solo the Citabria some time in the next couple of weeks, 3-point landings only, but that’s enough for me to build up some time.   I need to get good enough with all the basic airmanship and solidify my taildragger mojo enough to take on wheel landings.   This is important, because RV-7’s like to be wheel-landed.   The 3-point attitude is actually less than stall angle, so supposedly 3-pointing them leads to “The RV Dance,” which is a slight bounce, on the first touch and settling down after.  FA you can do, it’s just like that.

5 hours.

I realized yesterday that my means of measuring usable fuel was somewhat flawed, in that measuring leftover capacity in tanks drained is not valid.  It’s nice to know that there is .0312 gallons left in each tank after a draining, but what we really need to know is how much is left after the tanks are pumped dry.

So I went back up there and raised the tail up to flight attitude again.    This time it was a  little easier, because I found a weird old pallet lift at the back of the hangar, which allowed me to precisely lift the tailwheel to a desired height.   I drained out both tanks again, then starting with the right tank, I added exactly one gallon of fuel.  That’s when the fun started.

I’d made a fitting and tube to allow me to pump fuel from the firewall fitting into a measured pitcher below the airplane, and yes, I did make a bonding cable from a piece of 10ga wire and a couple of cleco clamps.   One end was clipped to a steel rod sitting in the pitcher and the other was clamped to the airframe to mitigate static buildup.  With this setup, I should have been able to pump the tank dry and measure the difference.

Wrong.   The pump buzzed and blew some air but no fuel.   Hmm..  Won’t prime.   I attached a rubber tube to the vent fitting and blew through it, thinking maybe a little more pressure would help the pump get started.   Oh yeah, that…  sort of works.   But then, I saw fuel dripping from the skin, outboard where it meets the spar.  WTF?

In the cockpit, there was a nice puddle of fuel on the floorboards.   Oh f—.  Stop everything, grab paper towels, mop up the spill.    This is where the lesson in finishing comes in.   When I reinstalled the fuel pump and covers, the intention was to get the covers and such back on so I could fit the interior, carpet, etc.  An actual functioning fuel system was not in the scope of the job.   It should have been.

There were three loose fittings at the fuel selector end, which were wet enough to feel.   Idiot.   After mopping up the fuel and letting the compartment ventilate for a while, I tightened those up and whaddya know, fuel starts shooting into the container when the pump runs.   I backed up and drained the fuel again, repeating the measured pour into the tank.   This time, I got 8 oz pumped into the waiting pitcher.  Add the 4 ounces of fuel left in the tank after the drain test from yesterday and that’s 12 oz of unusable fuel in the right tank.

The left tank went fine, only this time I got 11.5 oz of unusable fuel.

At this point, what the hell, let’s see if the fuel system will charge.   I reconnected the fuel pump feed line to the firewall fitting and hit the boost pump again.   And got a spray of fuel coming from the fuel pressure sensor hose fitting.    This was my second warning.   At this point I started to clue in and checked all the fuel fittings downstream of the firewall, which were plenty tight.    Fire up boost pump again, and look for leaks.  None firewarll forward.   But I got another puddle of fuel on the floorboards for my trouble.  Huh?

I removed the fuel fitting panel on the carb heat cover and yep, the fuel feed line and the purge valve return line were both loose.   How the hell did that happen?   Did I just not bother to tighten anything at all in there?

With those tight, the only leak came out of the sniffle valve on the sump, which is fine.  It was also just a few drops, probably because I’d left the throttle open when I ran the boost pump.

Finally.   I poured the fuel back into the tanks and buttoned everything back up.  Stress levels down.   A lemonade pitcher full of avgas is a scary thing and you can’t take your eyes off it for a second, because some fuel dribbling in the cockpit is one thing (on the ground at least).  Half a gallon of avgas spilling across the hangar floor is another.

So the takeaway from this lesson?   Check all the dependent systems before performing tests.  Ensure proper installation of dependent equipment before running live fuel.   That means pull the covers and check the fittings.  You can bet I’m not going to be nearly as complacent when it comes time to check the ignition system.

5 hours.

Today, Dave and I went up to OXR in his Defender 110 and we got three significant things done:   We set up the brakes, we measured usable fuel, and we pre-oiled the engine.   To pre-oil the engine, you take the bottom plugs out and crank it over with a bunch of new oil in it.   Like so:

There was more than this, but it sure was nice to see that prop spin around, even if only driven by the electric starter.

For usable fuel, we hoisted the tail of the airplane so we could perform the measurement in level flight attitude.  Score another one for the engine hoist.   Then we persuaded one of the vendors on the field to let us fill up two 1-gallon gas cans with avgas.   Then we put the fuel into two half-gallon pitchers with graduated marks on the side we’d gotten from the 97 Cent Store (yes, it’s actually called that but the pitchers were $1.29 each)  and we poured a gallon into each tank.   Draining the tanks back into the pitchers left us with a net loss of 4 fluid ounces on each side, as near as we could possibly measure.   Bottom of the meniscus, high school chemistry, all that.   4 fluid ounces works out to 0.0312 US Gallons, rounded off to 0.03, which gives us a usable fuel capacity in each tank of 20.97 US Gallons.

So we’ve got brakes, gas, and oil.   Now I need to time the mags, gap the plugs, and fire it up!

Some photos from Dave – Loading, loaded, and unloading: