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  #31  
Old 09-13-2017, 10:56 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
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One thing I've learned flying at non-towered airports with my non-RV, is that it's a very good idea to slow to flap speed and set up the right approach configuration (speed, flaps, fuel, prop to go-around position, etc.) well before entering the pattern - even before joining the 45 degree entry leg. This gets my attention out of the cockpit and focused on other potential traffic and the airport environment.

Another thing worth doing is getting the landing light on - makes your plane more visible.

So the order is: configuration first, then the pattern.

Dave
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  #32  
Old 09-13-2017, 07:20 PM
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flytoboat flytoboat is offline
 
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Location: Collinsville, IL
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Quote:
Originally Posted by scsmith View Post
The Lycoming performance charts in the Operating Manual show HP at various RPM and MAP combinations. At lower RPMs (below 2400), the power curves stop at various MAP, with a notation of "max pressure for continuous operation", presumably because Lycoming does not recommend operating at that low an RPM and high MAP. Its kind of like lugging your car in too high a gear. For reference, the chart for my IO-360-A1A shows 28 in. Hg limit at 2300 RPM. (figure 3-24 in my Operations Manual).

That being said, you make a good point about fixed pitch prop operation. The thing is, you open the throttle and start your ground roll, and although static RPM might be 2300, the RPM very quickly increases. And of course engine power increases with the increasing RPM, so by take-off, you are getting much higher RPM and close to max engine power. This takeoff transient is not what would be considered 'continuous operation.'

That is quite different from doing a go-around with a constant speed prop set at 2300 RM, where full throttle and 2300 RPM will be maintained for an acceleration and climb to some particular altitude where you may consider it safe to change engine settings, presumably either pushing the prop forward or closing the throttle some.

Of course, all this only has significance near sea level where there is enough pressure to be an issue.
Note also that the notion of "over-square" being a problem itself is disproved by the performance charts. The charts define the max MAP for each RPM and the boundary is WAY beyond the fake limit of 'square'.
My full throttle climb at 115Kts yields 2350RPM at 10.4GPH. I don't have my Manifold pressure sensor installed yet.
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  #33  
Old 09-13-2017, 10:17 PM
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N908RV N908RV is offline
 
Join Date: Mar 2007
Location: Warrenton, VA
Posts: 267
Default RV-8 3-point skittishness

Quote:
Originally Posted by scsmith View Post
I agree on all points. Sounds like our -8s are much the same. Although the issue with 3-pt landing the -8 doesn't seem to me related to it being nose heavy. I don't have any trouble getting the nose up. I can trim for 85 mph (75 kts) and just round out and hold it off. I can absolutely nail a 3-pt attitude, and just grease it on. Then the problems come. The issue is that it is still flying, even though all the wheels are touching the ground. It is squirrely and skittish, no weight on the wheels to brake, not much positive feel that it will go where you point it. One doesn't have much of a feeling of being in control. Rounding out to a wheel landing seems so much more positive.

I appreciate the affirmation that a few posts, like yours, has given me - I'm pretty comfortable with my strategy, and it is nice to hear others doing about the same. I sometimes have wondered if it is just me and/or my -8 that seems to want to land faster than some people quote.
Same for me in my old -8 with the CS BA Hartzell. It's odd that folks used to talk about the RV-8 tail shake at stall, but not referenced much as it relates to landing. I think that skittish-ness is exactly that. I would always notice that on three point landings. Less so on a flap-less landing.

I would fly the approach from base to final at 90 mph at idle power and be down to 80 mph in the round out. And almost always do a greaser tail low wheel landing. In my buddy's 8 with a CS Whirlwind 200RV for the same approach I have to keep in some power or the sink rate is much higher than with my old 8 with the same exact size pattern. Clearly more flywheel effect with the Hartzell.

It's always solid and stable on wheel landings. If you three point the 8 it gets skittish possibly due to buffet on the tail (aka: the tail shake). I could always three point 4s and 6s no problem.

YMMV.

Rob
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Last edited by N908RV : 09-13-2017 at 10:35 PM.
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  #34  
Old 09-14-2017, 05:20 AM
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chepburn chepburn is offline
 
Join Date: Apr 2006
Location: Ottawa , Canada
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I did transition training with Mike in 2011, and his pattern procedure is still the one I -generally- use to approach and land my CS RV8.

However, as other posters have mentioned, speeds and MAP setting will vary by aircraft model.. mine is a stabilized 80kts on base, and 75-80kts on final depending on conditions.

That being said, all those fixed numbers apply when you are by yourself in the pattern. You have to know your attitudes and sight pictures from any position in the pattern. At my airport (as at yours too I suspect) there are many different aircraft types that you could be stuck behind... all performing their own version of pattern... from a tight in pattern to the four mile student pilot bomber command final. You should be comfortable flying your A/C in all of those patterns, adjusting flap and MAP to suit.

In other words, Mike taught me a way to safely land my RV, but it was up to me to learn all of the other landing situations and use what he taught me to adjust for conditions.

My 2Cents

Chris
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