Newbie Question

[fredmoss]

Like many of you have already suffered, I'm going through that painful process of chosing a kit. I'm serioiusly considering an RV-9 and an Eggenfellner Subaru 2.5 XT, with Supercharger.

Van's website states the recommended HP for an RV-9 engine to be around 125hp. The 2.5XT has a considerably higher rating.

The Eggenfellner site shows a few RV-9 owners with 2.5's strapped to the front who just seem to love it.

Are horsepower comparisons valid between direct drive and PSRU engines?

Anyone want to talk me out of this?

[arffguy]

Van recommends 160 HP max on the -9. What does the 2.5XT put out?

[ronoc74]

Most people use 160hp in the -9A. The supercharged 2.5XT should make at least that but if you stay below Vne it's not a problem. The PSRU only loses a few hp. It would run very hot if it lost more than that.

The single-cam 2.5 package apparently weighs about the same as an O-320 but by Jan's figures the supercharged 2.5XT weighs nearly 40lbs more. It depends on how much useful load you need. An injected O-320 will be lighter and probably burn less fuel, but would be a bit slower at 10,000ft.

Best,
Conor

[H6 RV-6A]

The beauty of the 2.5XT supercharged engine is that under normal conditions, you can throttle back to maintain normal -9 speeds and enjoy low fuel consumption, but you still have the power available power up higher if you need to get above clouds/mountains. It is also beneficial if you fly out of higher airports.

[fredmoss]

Thanks everyone,

I have yet to hear a negative report on the Subarus (from anyone who has actually flown one).

The supercharger appeals to me because, hey! I just like to be high. There is nothing cooler than flying VFR on top.

My current Warriors and Archers are so lethargic at 10,000 and you can use the climb rate to measure continental drift.

I would really like to hear SOMETHING, ANYTHING bad about the Subarus -- I'm weary of anything that comes with no trade-off cost

[Larry Perryman]

Fred,

The 125hp is the minimal design hp. The airframe is rated for up to 160HP (O320) which is the most common engine.

I have the second 9 with a Subie to fly. Non supercharged. For me it works very well. I fly to Atlanta from Houston often since my wife's family is there. It generally takes me 5- 6 hours to get there with one stop along hte way. I am not into blazing speed or aerobatics so the engien works for me.

What you need to decide is how you want to use the plane. What is your mission? Then the engine decision will be a bit easier to resolve.

There should be a bunch of flying 7's and 9's at Sun-N-Fun this year. Jan is trying to get at least 12 there. Think that about 8 are signed up right now and looking for a larger crowd at Oshkosh.

Hope this helps a little.

Regards
Larry Perryman

[fredmoss]

I've scoured the web and have yet to find a picture of a Subaru XT throttle quad.

I'm assuming that there will be a throttle lever and a prop lever. With the XT will we need to monitor MP and RPM? I don't know if it's different with a PSRU engine.

Also, will an EIS give me ALL the engine monitors I would need in-flight? I would want tank indicators and a low-fuel annunciator as well. But, what about oil temps, pressures, fuel pressures, alt status -- all the things you see at a glance in the CLEAR check.

[Rotary10-RV]

Originally Posted by vanlle2000

A friend of mine has an RV-9A with an O-320/MT set up that he's let me fly several times. I love the airplane! I've taken two trips in it cruising at between 14-16000 ft. at WOT and 2450 rpm, it burns just under 7 gph at 170 mph true...maybe a tiny bit faster. Climb rate going thru 10K feet about 800 fpm. I'd expect maybe 500 fpm with a fixed prop.

No supercharger, no liquid cooling system, no reduction gears, no 40 lb weight penalty. And the engine was cheaper than a Subie set up since he got a good deal on a decent mid time O-320.

I'm having a hard time seeing any disadvantage here.

The kicker is if he flys enough to need an overhaul. New Subie short block <$3000.00 New Lyc cylinder (one!) $1800.00 w/o a piston. Not a bad choice though.