Speedy11(at)aol.com Guest
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Posted: Fri Oct 08, 2010 7:53 pm Post subject: Question for all |
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A Jarhead Target driver! And you're going to let him fly your airplane? Well, I guess if I let my F-22 driving son fly mine then maybe your RV can survive, too. But tell him no traps.
I am of the opinion that the RV-8/8A airframe is optimized with the 180 HP O-360 engine and a fixed pitch cruise prop. I believe the aerodynamics of the airframe are such that adding power above 180 HP adds very little to the top end speed and moderately to climb ability. The 180 and fixed pitch combo keeps the weight low and fuel flow low while providing reasonable performance.
HOWEVER, having said that, let me say it all depends.
If you are using a turf or short runway, then a CS prop is important - as is additional HP.
I have a MT 3 blade CS prop on an IO-390 and I am very happy with the configuration. The extra HP is available if needed and the CS prop climbs like an angel. I'm airborne solo in about 3-400 feet and I accelerate quickly to 115KIAS on the deck. A climb to pattern altitude then takes only 6-7 seconds with a final airspeed of about 95KIAS. I can get 184 KIAS at 1000' MSL, but it drinks a lot of gas. A 2 blade will go a bit faster. Cruise is about 165 KTAS at about 8.2 GPH. With my engine/prop I'm able to climb to FL240.
Acro is easy with the 3 blade and 210 HP. A fixed pitch will require slightly more finesse to avoid overspeeding the engine on downlines.
IFR in the plane is easiest with an autopilot. It is a challenge to hand fly IFR while shorting charts, tuning radios, making radio calls, etc. I've found I must be very organized to fly IFR. An autopilot makes the task much easier. It gives you time to turn your attention to those numerous things that are required in IFR. Add rain to the mix and an approach to mins and you'll have your hands full.
The carbureted vs injected arguments by Kelly are on target. I have a ram air system for my injectior throttle body that will auto revert to filtered alternate air if the intake should be clogged by ice or a bird.
The RV is ideal for local fun flying and any engine prop combo will work, but an injected, inverted fuel and oil engine with a CS prop is best.
For CC IFR flying, I'd make sure to have a Primary ADI plus backup, IFR certified GPS, ILS, and a good autopilot.
I've flown all spins and acro maneuvers except the hammerhead. I've flown CC from Daytona Beach to Burlington and back. The airplane is fun for all the above.
Stan Sutterfield
www.rv-8a.net
Quote: | Question for all:
My son & I are looking for an RV-8. Our mission is split between cross coun
try (must be IFR) & light sport aerobatics. I am a 1500 hr pvt pilot & he i
s a Marine F-18 pilot. Our questions are:
1. What are the advantages & disadvantages of injected vs. Carbureted?
2. What are the advantages & disadvantages of a constant speed prop.?
Thanks,
Bill
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