Kit Aircraft Modifications

Good Morning,

There has been a number of instances of Van’s flap motor quitting as a result of the lubricating grease getting into the motor housing and gumming up the brushes. This causes the motor to fail. Pilots have had the motor fail in all positions. This can be an awkward situation that tends to present itself either in the beginning of your flight or at the end. I think that it would be most dangerous during a missed approach where you need to get the flaps up to achieve a positive rate of climb on the overshoot.

My friend Gary Wilcox just posted a great article on vansairforce.net that shows how to take the motor and linear actuator apart to remove the excess grease. I will re-post his article below.

Build Smart and Fly Safe

Dave

Once again I find my flap motor not wanting to go down, oh well, better than not going up after take off. I had cleaned the shaft of the motor before, but did not fully disassemble the unit to clean it out of grease. So, out to the hanger I go to resolve this issue with hopefully a better result than the last time, it lasted 45 hours. First remove the flap assembly from the plane, hard to see in this pic, but there is quite a bit of grease on the shaft. Some is good, but this was to much.

 Remove the two screws from the top of the motor.

Gently pry off the motor cap.

Pull off center body that has the magnets. You can see on the top of the motor where the brushes contact the shaft, all gummed up with oily goop.

Remove two Allen screws from bottom of housing and remove screw unit.

The larger hole was full of grease, this is what works up into the motor to stop the brushes from working properly. Clean out the excess grease.

Clean off as much grease as you can, but be sure to leave some on the shaft that comes out of the housing and attaches to your flap weldment. Also, there are tiny bearings at each end of the motor, don’t put anything in them to remove the grease in them. Clean off the ends of the brushes and shaft where the brushes touch. I used a light touch with a Scothbrite pad. Assemble the unit, putting a drop of Lock-Tite on the Allen screws (was on them when removed) and be careful not to bend the little springs that hold pressure on the brushes. People have different ways to hold these in when reassembling, I just used my fingers, no big deal. Re-install and test. Mine worked fine. Hopefully, by doing the full grease removal it will last a long time.

Best part, it was only an hour job, start to finish.

This was how I did this fix and in no way am an expert. This info is worth what you paid for it. Use it wisely. Your mileage may vary.

Gary

Hi All,

I was out at the airport this morning working on the fuel flow monitoring system in my RV-10. I am not getting any reading on my AFS 4500EE. As you read in the previous post, I have 2 fuel transducers. Today I isolated each of the transducers and fed them directly into the 4500EE. Happily, each of them performed perfectly.

This leads me to the resolver box that is supposed to read each of them and subtract the supply from the return. Maybe I have them wired backwards and the resolved output can’t go below zero? That might lead to the output of zero on the monitor. I will have to run the wires back to identify the individual fuel flow transducers and then look at the resolver box wiring diagram to see if I have the supply and the return connected properly.

Something to look into over the weekend.

Build Smart and Fly Safe

Dave

Hi Everyone,

The LS1 has a fuel rail that requires unused fuel to be returned to the tank. This presents a problem when you compare fuel flow monitoring with the IO-540 set-up. As there is no need to return fuel to the tank with the Lycoming you only need to have one transducer to monitor the flow.

My set-up requires that I monitor the fuel flow in both directions and then subtract the two to determine the usage. I use 2 of the Red cube fuel flow transducers which plug into a resolver box supplied by Advanced Flight Systems. This box takes the signal from the individual sensors and subtracts the supply from the return and sends the resolved signal to the EFIS.

Tomorrow I have to check the installation against my wiring diagram because I am reading 0 flow when the engine is running. Just another in a list of wiring educational challenges I have had to rectify before I can take the plane up in good conscience. Luckily the list is almost completed.

I need to look at a brake line fitting that I am getting a slight seep from and some engine compartment items that need to be completed. I’ll say it will be a week to a month before I have her prepared for flight but you know you can’t hold me to that!

First flight will be on Tuesday!!

Build Smart and Fly Safe

Dave