Lycoming engine mounting ears

To ready the Lycoming IO-540 C4B5 for the RV 10 the engine mounting ears must be changed. The C4B5 comes with the large diameter mounts. Where the Van's engine mount requires the small diameter ears. The accompanying picture is of a used example of the correct part. The required mounting ears are Lycoming's part # 70456. A none PMA'D experimental part is available from A.E.R.O. Here is a link to their website www.aeroinstock.com Also, they are available second hand or from Lycoming.

Changing the Propeller Governor

As we mentioned before there are some things that need to be changed to get the Lycoming IO-540 C4B5 to fit our use on the RV 10. One of these is the propeller governor. The original unit for the Piper Aztec won't work for several reasons. First it's too bulky to fit under the RV cowl, but more importantly being it is used on a twin engine aircraft it feathers the opposite direction from what we need.

In the picture you can see the difference between the original on the right and the MT governor on the left, which is available through Van's Aircraft.


Of course the fun doesn't stop here! As you can see in the photo the mounting flange on the MT unit is thicker. So the mounting studs will need to be replaced with the longer ones. These are available from Lycoming, however I purchased mine through ECI (Engine Components, Inc.) at about half the cost. Yes, they will deal with us builders. The ECI part number for the new studs is AEL31C16. If ECI sounds familiar it's because they make Titan engine cylinders and other aircraft engine parts. Their website is www.eci.aero.

Make sure you get you Lycoming engine manual out and install the new bolt studs according to the manual. If this is new to you ask your EAA technical conselor or and A&P. Engine cases are too expensive to mess-up!

Fitting a Lycoming IO540 C4B5

The prototype RV-10 aircraft used a Lycoming IO540 D4A5. The second factory plane used a Continental IO360. To save a few shekels we used a rebuilt variation on the aircraft engine the Lycoming IO540 C4B5 out of a Piper Aztec airplane. Of course there are some difference between the two engines such as:
Power rating

Engine mounting ears

Hot Prop Flywheel

Prop Governor

Prop Governor mounting studs

Manifold pressure source

Modifying the RV-10 lower cowl mounts

Experimental aircraft have the advantage of allowing the homebuilder to make modifications when needed. One that has come up with other RV-10 builders is the two lower cowl mounts will crack. The original Van's kit called for using aluminum hinge material. It's referred to on pages 41-7, 41-8, 47-6. Others have replaced this with 0.063 aluminum sheet and nut-plates with good results. We followed suit.

The dimensions of the 0.063 aluminum is 1.5" by 6 ". The smaller aluminum spacer is made per the plans. The hardware pictured consists of 8 each K 1000-8 nut-plates, nylon washer 5610-18-31 and AN526C832R8 stainless screws. These are all available from Van's Aircraft.

6,000 RV aircraft now flying!

Well it happen today the 6,000 Van's airplane kit is flying. As fate would have it, number 6,000 is an RV 10 registration number N510RV. That makes 166 RV-10s flying according to Van's website. Louis Palmenter of Rhome Texas is the latest happy builder.