An Owners Experience with an O-235 powered RV-9a
Its time that an RV-9a owner with a 118 hp O-235 expresses his non-testosterone induced feelings about this setup. Lets remember that Rv-9's are non-aerobatic and were designed for economical moderate speed cruising.
I reside in N California, there are some calm days in the summer, but mostly I fly in low to moderate turbulence, and it usually gets worse in the afternoon when the thermals get active, sometimes up to 12,500 ft. This means flying at Va, which is between 110-117 mph depending on weight, so on those days more power has no advantage. On calm days I cruise at 75%, 2500 rpm, 8000 ft, at about 130 kn/hr, and burn about 4.1 g/h. At 2600 rpm, 140 kn/hr, I burn closer to 5 g/hr. So, Im delighted with the fuel burn, range, and speed. The recent dual P-Mag addition really improved the fuel burn. So my predicted fuel savings over an O-320 for the last 3 years after 400 hours is over $2k. Fuel savings will be greater as 100LL steadily gets more expensive, and when it is not available, the 8.5 - 1 compression ratio makes 93 octane auto gas an alternative. Another savings is the recommended 2400 hour time between overhauls. The solid lifters do need to be adjusted occasionally, its a pretty simple process and we do it once a year. We are very happy with our Catto composite fixed pitch prop. If you choose an O-320 or larger engine for your 9, then for $7k more, you could pop for a CS prop.
At my home airport KSTS (elev 125 ft) I can easily climb over 1000 ft/min. I would certainly not recommend this setup for a 10k foot home elevation in the Rockies. I can fly with full tanks, 1 average size passenger, and 75 lbs of baggage and will not be over gross weight. I take off from Truckee (elev 6000 ft) regularly, and T. O. distance is about 3000 ft. with passenger on hot afternoons. As mentioned above, I can't keep up with my buddies in their 7s and 8s with their IO-360s, but it has never stopped me from tagging along. My O-235 is always the easiest to start, especially when hot, and if I take off first, I'm not too far behind them when they land, I've burned half as much fuel, and I'm tied down, washed my hands, and started my first iced tea long before they all finish refueling. I have traveled over the Sierras on a few occasions at 13,500 ft and felt very safe and comfortable high above Yosemite's Tioga Pass gazing down at Half Dome in the distance, knowing that if I desired, I could have gone higher.
Yes, there are times on cross country flights, that I wish I could travel a few miles/hr faster, but I would only save maybe 30 minutes on a trip from Santa Rosa to Long Beach (360nm) where my daughter lives. Also, my weight and balance is always near the back edge of the window since the O-235 is a little on the light side.
When I was a kid, I had a '65 Ford Mustang with a small block 289 cu. in. V-8. A few more cubic inches and twice the cylinders as my O-235. It was plenty fast enough for me and it didn't burn much $0.25/gallon 100 octane leaded gas. I guess that I have not changed much, and really can't help being myself. So, I enjoy flying behind an O-235, and I'm pretty satisfied with this setup, and I have not had any complaints from my passengers that the plane is too slow. I don't see a significant advantage of a larger engine, other than traveling a few m/h faster, and of course we can't forget the pervasive testosterone factor.
