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  #1  
Old 08-16-2011, 08:30 PM
campi campi is offline
 
Join Date: Jun 2007
Location: Washington, D.C.
Posts: 205
Default RV-4 Approach Speeds and POH

I recently bought an RV-4, and would like to get some feedback on approach speeds. The airplane has a 160 hp fuel injected engine, and a fixed pitch 79 Sensenich prop set for cruise. It weighs 986 pounds empty. It does not like to slow down or come down!

In the pattern I have been flying 100 mph on initial approach and downwind, slowing to 90 on base, and then on down to about 80 mph with full flaps on final. It feels solid at that speed, but I wonder if I'm approaching too fast, particularly when solo and with half tanks.

Also, if anyone has a POH that they could share for a 4 similarly equipped to mine, that would be most appreciated. I'm trying to put one together now.

Thanks,
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RV-6 (Purchased and sold)
RV-4 (Purchased and sold)
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  #2  
Old 08-16-2011, 08:43 PM
Sid Lambert Sid Lambert is offline
 
Join Date: Jul 2005
Location: North Atlanta
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Practice slowing it down a bit. 75 MPH works well for short final and it makes for plenty of stability in the flare. You can stop with just a touch of brakes in 1800' or so from the end of the runway.

I also practice dragging it in all the way down at 65 MPH. At that speed you use power until you are ready to touch down and it touchs as soon as power is reduced. I can turn off in 500 feet with that speed but there is very little margin of error.

I use 80 MPH with a passenger, 75 solo and less just for fun in smooth air.
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  #3  
Old 08-16-2011, 09:16 PM
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Kevin Horton Kevin Horton is offline
 
Join Date: Jan 2005
Location: Ottawa, Canada
Posts: 2,352
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Keep in mind that these are not production aircraft, where each one of a model is assumed to exactly like each other one. Errors in the airspeed system may vary quite a bit from one RV to the next, so IAS values that work for one pilot in one aircraft may be all wrong for another pilot in another aircraft.

Go up on a very smooth day, with no turbulence, and see exactly what the IAS is at the stall with landing flap and idle power. Then try simulated approaches at altitude at ever so slower speeds, with a simulated landing flare at the bottom of each one. Then, try it for real, with approaches to the runway, decreasing the speed a knot or two on each approach. Pay very close attention to how the aircraft responds in the landing flare. You will eventually find that at some particular approach speed the flare is getting pretty dicey. Add a few knots for a buffer (to allow for safety with the airspeed variations you see in typical wind conditions) and call this speed your absolute minimum approach speed. I suggest your minimum approach speed should be at least 5 kt greater than the speed you demonstrate on that perfectly smooth day.

If you have a different technique for short field landings (maybe you add power during the flare instead of pulling to idle), then do it all over again with this technique to define your minimum short field approach speed.

The minimum approach speeds you find are valid at whatever your test weight was. If you increase the weight, you'll need to bump the minimum approach speeds up too. A 10% weight increase would require a 5% increase in speed to keep the same margin to the stall.
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  #4  
Old 08-17-2011, 07:15 AM
fixnflyguy fixnflyguy is offline
 
Join Date: Jan 2006
Location: Winston-Salem, N.C.
Posts: 942
Default RV-4 speeds

Fernando,
I have a -4 with a 160hp, wood Sterba prop, weigh about the same as yours. I also fly DW at 100, usually do a blended base/final reducing to 70 on short final if solo, hold 80 if I have a pax. I agree with Sids #s also, and you can really get slow with power, but nose will be high and sink rate must be watched at those conditions when power is reduced. I often practice (at altitude) descending turns at 60-70 mph with flaps 1/2 and full as would be done in the pattern. RV's do very well as long as the ball is centered. Its also good to practice slips...it will help you slow since no C/S prop. Keep practicing !

Bill E
N76WE/RV-4
Advance NC
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  #5  
Old 08-17-2011, 07:56 AM
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rbibb rbibb is offline
 
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Location: Freericksburg, VA
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Landing a -4 is easy, landing it well takes practice. Mine floats like crazy at anything above 70 mph on short final (solo). It takes getting used to to slow it down that much and even with the flaps it just seems to hang in the air.y
But practice makes perfect.

Key for me is getting it in my head that I really needed to slow it down. Of course I had the most trouble after flying a T-6 that has no problem coming down like a brick when you get under 90 on final.

Go to altitude and figure out what IAS works for your plane and then do a dozen loops around the pattern.
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  #6  
Old 08-17-2011, 09:34 AM
Christopher Murphy Christopher Murphy is offline
 
Join Date: Feb 2007
Location: colorado
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Default approach speed

Old timers taught me to find the stall speed clean and then add 15 percent for the approach speed. My 4 stalls at 54kts I use 70kts on final and may slow to 65 over the fence but no slower. A skilled pilot can fly slower of course.

The speed you fly may depend on what kind of landing you plan to make.

You should know what your airplane handles like at low speeds and you will be able to feel if you are at the correct speed. The RV's are honest flyers but inept or inattentive pilots can and do spin in on the base to final turn.

Chris M
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  #7  
Old 08-17-2011, 01:07 PM
luddite42 luddite42 is offline
 
Join Date: Mar 2010
Location: USA
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Quote:
Originally Posted by Christopher Murphy View Post
Old timers taught me to find the stall speed clean and then add 15 percent for the approach speed. My 4 stalls at 54kts I use 70kts on final and may slow to 65 over the fence but no slower.
I think you meant to write 30%.
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  #8  
Old 08-17-2011, 07:52 PM
gmann750 gmann750 is offline
 
Join Date: Jan 2011
Location: orwigsburg pa
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I just started flying my 4 in June and I use a turning power off approach and trim for 70 mph on base and final and slip all the way to ground effect it makes for a nice tight pattern, I'm very new to this though I took me a while to figure out what worked for me. It's all fun though. 160hp catto 3 blade
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  #9  
Old 08-17-2011, 08:36 PM
campi campi is offline
 
Join Date: Jun 2007
Location: Washington, D.C.
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Default Thanks - and POH?

Thanks to everyone who responded. I have been focused on staying in the pattern to practice landings, but I need to get up to altitude and experiment with speeds. I suspect I can in fact slow down from 80 mph. I just need to find out by how much.

Now, does anyone have a POH they can share for a 4 with a similar configuration to mine?

Thanks again.
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RV-6 (Purchased and sold)
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  #10  
Old 08-17-2011, 09:07 PM
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AX-O AX-O is offline
 
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Location: SoCal
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I have the same configuration as you. It took me a while to figure it out but once I did, I started flying formation. We fly 87 knots on downwind, 78 knots on base and 70 knots on final. Then I bleed it down to 65 over the fence. If you are thinking about flying formation in the future you may want to try those numbers. They work well. Much higher than 65 knots and I float for ever.
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