ELT & Strobe Power Supply Installation with Van's Mounts

Van's Aircraft has come up with a nice pair of ELT/Strobe power supply mounts for both the right and left sides of the RV 10. These are not part of the kit, but are available separately. At the time I installed these they did not make one for the right side. But with a little work I was able to get it to fit. As you can see they are mounted into the J channels with "pop rivets." They come pre-punched for the Whelen strobe power supply with the rivets and nutplates included. To mount the ELT I had to drill new mounting holes in the left mounting plate that matched the Emergency Beacon Corps unit. All in all these mounts make for a nice clean installation.

Modifcation of the Front Fresh Air Vents

Being value minded, when it came to the front air vents for the RV 10, I wanted a nice set of vents without paying an arm and a leg. OK well maybe just an arm. The simple solution was the fresh air vent AV125B available from SteinAir. Aircraft Spruce carries as well. Most people who use these are also using a custom instrument panel, however I had opted for the stock panel from Van's Aircraft. So how does one mount the vents without an extended panel? The idea for the fix came from the Matronics group. First cut off the bell end of the cabin side of the vent and then use a adapter made from a rubber pipe coupler from Home Depot. You only need one coupler and then cut it in half. Using fuel tank sealant I glued the coupler to the plastic vent and a hose clamp secures the vent in the coupler. One other nice touch is to take some stainless wire screen and glue it into the middle of the plastic neck with fuel sealant to keep the bugs out.

Lycoming Oil Sump Clearance on the RV 10 Engine Mount

A concern that comes up with different variations of the Lycoming IO 540 is will the oil sump clear the lower cross tube on the Van's Aircraft motor mount? The tube in question is pictured to the right and is the one that runs between where the two lower vibration mounts bolt on. This has become a big enough issue that Van's wrote a service letter on it: RV-10 Engine mount/Engine interference.

As you may recall the Lycoming IO 540 C4B5 I'm working with is from a Piper Aztec. The good news is there is no interference issues with this engine. The clearance was right at 3/8". I'm not sure if all C4B5 use the same oil sump, but the right engine on a 1974 Aztec works just fine:)

If there is interference there are two fixes I have heard about primarily through the Matronics RV 10 e group and these are: 1. get a different sump or 2. cut out the tube and weld in a new one that is bent to clear the oil sump. I'm just glad it was a non issue for me! If you are not familiar with the Matronics RV-10 Aircraft group check it out. It is a great resource: Matronics sign up

Lycoming IO 540 Ring Gear Assembly (flywheel)

Another item that is an optional change is the Ring Gear Assembly. Why would anyone want to change it? Well, the one that came with my engine was setup for a Hot Prop or deicing propeller. As you can see in the first picture the hot prop gear assembly has greater mass than the standard ring gear assembly shown in the second picture. In short it's a way to save some weight in the nose of the RV-10. The hot prop assembly weighs 8.86 pounds. Were as the standard ring gear assembly weighs 6.9 pounds.

A couple of things to keep in mind about this change out is to use the same tooth count on the starter ring gear that matches the starter being used. They come in 122 and 149 count. Also, you will probably want to stay with the same alternate gear pulley size. The standard Lycoming size is 9 3/4". This is the size recommend for use with Plane Power alternators.

While changes such as this are legal on homebuilt aircraft, it can change a certified engine to an experimental engine depending on the part used. Also, it's important to document changes such as this in you engine log book for later reference.

Manifold pressure tap on the Lycoming IO 540 C4B5

If you are planning on using an IO 540 out of a Piper Aztec keep in mind the manifold pressure tap is on the number 6 cylinder (this the left rear cylinder from the pilots view) whereas Van's has used a tap off of the number 5 cylinder (right rear.) I mention this as a heads up to make sure the old pressure tap off the number 6 cylinder gets properly plugged, otherwise that cylinder would run really lean if at all!



In the first picture you can see the number 6 cylinder with a new plug installed with fuel lube and torqued to the correct setting.










The second picture shows the newly installed manifold tap as used on the RV 10 aircraft.

Lycoming C4B5 Power Rating for the RV10

As we discussed earlier the IO540 C4B5 has a different power rating than the IO-540 D4A5 recommenced by Van's Aircraft. These are 250 HP at 2575 rpm for the C4B5 and 260 HP at 2700 rpm for the D4A5. Everything I have read points to the fact that they are the same basic engine and capable of running at either rpm/power rating. It's just Piper derated the C4B5 by running it at a lower rpm for the Aztec. If you would like to explore more about the different Lycoming 540 series aircraft engine try this link Lycoming 540 reference.