Kochman Family RV-10 Rotating Header Image


Panel Lighting

I haven’t flown our airplane at night yet, though it is equipped for night flight.  One shortcoming is the interior lighting–it’s easy to see the screens and lighted instruments, but difficult to read the switches and other controls.  I fixed this today.

There are inexpensive, dimmable LED light strips available now in a variety of colors.  They’re self-adhesive, too, which makes them really easy to install.  We already had a lighting controller and a dimmer knob installed, so I just needed to stick it on and run the wires to the lighting controller.  Here’s a picture.  We chose red, since it’s supposedly less harmful to night vision.

Repairman Certificate

Finally got around to getting the repairman certificate.  The name is a bit of a misnomer–no authorization is required for anyone to work on the airplane, but the repairman certificate allows me to sign off on the annual inspections, the first of which is due by the end of February.  A guy from the FAA came out to check out the airplane and my paperwork (especially the builder log) and issued the certificate.  I’ll get my “real one” in a few weeks.

Update: here’s what the permanent one looks like.


Still not Flying

Paine Field, 1 p.m. Thursday.

After getting the inspection done, we needed to reinstall all the cover panels, the interior, seats and cowl.  That took much longer than I’d thought.  Then I noticed the nosewheel valve stem had been damaged when the avionics shop moved it, so we had to replace the nose tube.  With everything finally ready, the weather has been terrible for days.

Every day I feel like a little kid that woke up on Christmas morning and was told Santa got stuck in traffic and might be here tomorrow.

Our Airplane is Officially an Airplane!

Today we had the official airworthiness inspection, and we passed, so our project is now officially an airplane.  Here are a few pictures.

Weighing the plane

Before the inspection, it’s required to weigh the plane to, well, know how much it weighs, so you know how much stuff it can carry.  Additionally, it’s important to know where the center of gravity is, because after adding people, baggage, and fuel, the resulting center of gravity must be within a certain range for the airplane to be controllable.

First step is to jack up the plane so the scales can go under the wheels.  Dave Parsons (RV-7 builder) gave me his homebuilt wing jacks, which are basically hydraulic  jacks on a wooden stand.  The jack points are at the wing tiedowns.

After getting the jacks precisely positioned and the wheels chocked, I started lifting, alternating between the left and the right sides.  The nosewheel stays on the ground for now.  Here’s a picture taken just after I got the wheels high enough to slide the scales under.

With the scales under the main wheels, I lowered the jacks.  It’s also important that the plane is level when it’s weighed (and when it’s sitting on the ground, it’s not level).  Miraculously, with the main wheels on these scales and the nose wheel on the floor, the plane is exactly level.  However, the nosewheel also needs to be weighed, and with a 3rd scale under it, the plane would no longer be level.  My plan then was to note the weight on the main wheels with the nose on the ground, then put the nose gear on a scale and add/subtract from the nose weight based on how much the weights on the main wheels changes.

Here’s the plane sitting level.  Not sure whether it’s clear in the picture, but in person it definitely looks different.  The tail is much higher.

To lift the nose, I needed to pull down the tail.  To do this, I rigged something up with a furniture dolly, sand bags, and a tiedown strap.

Tail goes down, nose goes up.

For the nose, all I had was a bathroom scale.  It’s the electronic kind that you have to “tap” on to activate, turns off after ~10 seconds of inactivity, and “locks” when it has a stable weight on it.  This meant I had to tap on the scale, then run around to the tail to lower the nosewheel.  I also had to try to lower the nosewheel as slowly as possible so it didn’t slam down and break the scale.  It worked okay.

After that, I raised the wheel again, removed the scale, and put the nosewheel back on the floor.  The other important part of this process is measuring where the wheels are in relation to the airplane.  Due to manufacturing inconsistencies in the gear legs and to a lesser extent other parts, there are slight variances from plane to plane.  I used a plum bob to mark on the floor where the leading edge of the wings were, then measured how far each wheel was from that.

Strangely, when I put the nosewheel back on the floor, the left main wheel weight was the same, but the right increased by 4 lbs.  This could have been due to side load on the wheels–not sure.  I decided to take the average of the two measurements.  Also interesting, the second weighing had the left and right main gear weights exactly the same.  Here’s a picture of both scales showing 616.

The last step was to jack the plane back up, remove the scales, and lower it again.  Here are the results:

  • Left main: 616 lbs, 123.99 inches aft of datum
  • Right main: 614 lbs, 123.84 inches aft of datum
  • Nose: 376, 49.94 inches aft of datum
  • Total weight: 1606 lbs
  • CG: 106.6 inches aft of datum

Note the plane was weighed with everything on, except the wheel and leg fairings, and of course without paint.  These items will add weight, but still think we should end up with a plane that’s not too heavy.  Note we also have a full interior installed.

This is very close to what Van’s shows in their sample data, which is reassuring.  Thanks to Joe Hull for letting me borrow his scales.

First Engine Start

Well, it runs.  Lessons learned:

  • Use a checklist.  For some reason, I decided that because I wasn’t going flying, I didn’t need to use a checklist.  Well, after twice trying to get the engine to start, I realized I should probably turn on the ignition switches.  Also, after doing a complete ground run (including a minute or so at high RPM to cycle the prop), I realized I had the Lightspeed breaker pulled (the other side is a mag).  I thought it sounded a little rough, but thought it could be the preservative oil on the cylinders or something else.  Inexcusable, really, to not have all this stuff checked out ahead of time.  On the plus side, I was surprised how well it ran on just one mag.
  • Be sure of the tachometer setting on the EMS before starting.  I thought it should be 3, turns out it’s 1.5 (for the Dynon on the p-lead), so I was getting 1/2 the actual RPM displayed.  This, combined with the rougher running, caused me to run a little faster than I’d have liked.  CHTs maxed out at around 300, so thinking I’m probably okay.
  • Had a flame shoot out of the exhaust when I turned off the mag (to do the “mag check”, before I realized the Lightspeed was off).  Pretty sure this was “afterfire” (unburned fuel/air mixture in the exhaust).  Made things exciting for the people watching.

After fixing things and feeling stupid for a few minutes, I fired it back up with both ignitions this time.  Ran great, lower EGTs.  It was far from the perfect first engine start I’d hoped for, but I’ll take it, given everything else works.

First start, on one mag:

Starting it later on both ignitions:

Door Seals

We’re using nonstandard door seals–they’re foam seals that stick to the inside face of the door.  Here’s Kelly installing them, making sure the foam is the right thickness all around the door (it varies).


We’re getting close to starting the engine, so now’s the time to find out if there are any fuel system leaks.  We’d already pressure tested the fuel tanks with air, but we wanted to get some real fuel in there to make sure all the lines and fittings are good.

We walked out to the self-service fuel area at Paine, and filled a 5 gallon can.  It was really windy.  Also, it’s worth noting that the fuel came out *really* slow (barely better than a gallon a minute), I think because the hose was almost completely rolled up.

We took this back and filled the right tank.  So far, so good.  John Adams stopped by, so we put him to work quickly holding our makeshift funnel.

Later in the day, we went back for 5 more gallons for the other tank.  This time, we used the other pump and pulled the hose out a little, and filled it in less than a minute.

We dumped it in the other tank, and no leaks there, either.

With 5 gallons in each tank, it was a great opportunity to test the rest of the fuel system.  I disconnected the fuel line from the fuel servo and Kelly switched on the fuel pump.  After just a couple seconds, the fuel was flowing, so no need to prime the pump.  We let it run for a few seconds, switched tanks, and let it run some more.  I estimated the fuel flow at around 75 gallons per hour, which is plenty.

Project Visit

We had a “project visit” today from my EAA chapter–I invited anyone who wanted to come to check out the project and point out anything that could be a problem.  We had 6 people show up, which was great.  Thanks much to Mike Culver, Chad and Bekah Hankins, John Marzulli, John Adams, and Jason Hills for stopping by.

Stick and Stick Grip

We’d planned on using the Tosten grips, but ended up with the Infinity grips, mostly because the Tosten grips are tilted so far forward, even with bending the control stick a pretty good amount.  The Infinity grips feel nicer, too, so it’s a good change.  We needed to set the angle of the grip, so that it matches the natural angle of the arm/wrist/hand, so here I am trying to figure out what that angle is.  Kelly thought it was funny.

We bent the stick significantly, to try to accommodate the Tosten grips, so even with full forward elevator, we still have two “fingers” of space between the top of the grip and the panel.

This means that with the stick fully aft, it’s really low and in the crotch.  Where I’ll have the seat positioned, it won’t be a problem, but if there are any “round” pilots down the road, we may have to do something.  Worst case, we can buy a new stick and do it again.  That said, if the goal is for the stick not to hit anything at all, we just barely made it with the alternate air knob pictured below.  Some people say the stick needs to be able to be moved in any position without hitting anything, and others say it doesn’t matter because you’ll never have the stick that far forward.  Some inspectors care, some don’t.  Anyway, we’re going with what we have for now.