IO-240 in an RV-9A

[surface warrior]

Has anyone installed an IO-240 (125HP) engine in an RV-9/9A?

Just curious. I'm considering building the -9A and thought the 125HP would be a good engine given the low fuel burn (7 GPH) with the 36 gallon tanks. Should give 5 hours flying time without reserve.

Not sure about the speeds verses the IO-320 though. However, with the IO-320, would lose an hour flying time because of the higher fuel consumption.

Thanks,

Surface Warrior
RV-9A (pondering)
N827CB (reserved)

[Spike]

You would definately get good performance compared to your typical production aircraft along with the good fuel burn. Personally, I cant stand being in a small plane fore more than 3 hours or so, so, to me the extra endurance is not necessary. You will also lose out on gross weight.

However, you will gain alot in the endurance, cost of building, & cost of operation areas. I would think that if it fits your use model then you should go for it. Though I dont think that Van's has ever published numbers for a 125hp engine, only 118, 135, & 160 HP.

-- John

[TT]

There's a misconception that a small engine will get better fuel consumption than a bigger engine. Nothing can be further from the truth. As a teen ager, my dad let me buy my first motorcycle. It had a whopping 125cc, while dad's was 500cc. We drove up to see one of the first "road races" in the US. the distance traveled was 90 miles. I could not keep up with dad's bike , so he slowed way down, allowing me to "draft" him. Dad was a stickler for fuel consumption. We arrived in Milwaukee, and filled up with gas. We both started with full tanks. Dad took 1 gal (that's correct 90mpg), I took 1.8 gal. or 50 mpg. So much for small engines. This lesson remains to date.
Shortly after I receiveved my ticket, I made an appointment to rent a 172 for my Sunday ride. One was not availabel, so I settled for a 150. We rented the planes dry and had to refill the tanks at the end of out flights. Round trip (solo) was 1 hr. fuel added 9gal. (that's right). I was not pleased that I had to fly the 150. the FBO suggested that I get checked out in Pipers or other available ACs. An instructor was present, and I was checked out in an early Warrior (150hp, 0320). The check ride included various maneuvers, and flight charistics, and , of course 2 on board. We fill the tanks, and 1 hr used 9 gal.
Much the same when I moved up from a 140 Cherokee to an Arrow.
The smaller engine has to work a lot harder to move the same mass. In addition it flies a lot slower. In the end the smaller engine will use more fuel.
This is not to say that we should install an O540 in a -9, but for the small weight penalty of the engine, there would be a 2# pound per cubic inch of engine displacement loss for the larger engine, (7# for the 240, 5# for the 320) with added performance. result, less fuel "used" despite the slightly higher fuel consumption rating of the larger engine, not to mention the climb and higher cruise speed. And after all, isn't that what RVs are all about?

[captain_john]

I always buy the engine option.

Go for HORSEPOWER!!!

Besides, you end up losing power at altitude, anyways.

You can always throttle back, if you like!

More power! Argh, argh, argh!

CJ

[728GD]

There's no replacement for displacement!!

[Snap]

yay as I walk through the valley of death, I will fear no evil, AS I AM AT 40,000 Ft AND CLIMBING