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  #11  
Old 06-16-2009, 12:15 PM
Beancounter Beancounter is offline
 
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Default Baby seat

I too have incorporated seat anchors for a baby seat. Would anyone like to share how they did it. Send me a PM if you don't wish it to be public.
Matt
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  #12  
Old 06-16-2009, 12:54 PM
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videobobk videobobk is offline
 
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Like Bill, I use 65/70mph solo/two people. I have a FP and find 60 fine IF there is no chance of wind gradient. Also don't forget to add gust factor and a little for wind gradient if the winds are high. I have found I can come down final with power as low as 57 mph (1.3 X stall) but I wouldn't be comfortable power off. Glide starts to resemble a brick. I find the 9 much harder to land if you are fast.

Bob Kelly
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  #13  
Old 06-16-2009, 02:25 PM
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Kevin Horton Kevin Horton is offline
 
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A Vref speed of 1.3 times the stall speed is used on a lot of larger aircraft. There are a few things to keep in mind:
  1. The margin of 30% between the stall speed and the approach speed represents quite a few knots if the aircraft has a high stall speed, as with airliners. But, it is only a few knots on slower aircraft. A 30% margin might not be enough on some aircraft.
  2. The pilots of these big aircraft usually add 5 or 10 kt above the published Vref, and only decelerate to Vref just before the wheels touchdown.
  3. Many aircraft have significant airspeed system errors at low speed. A landing reference speed (Vref) of 1.3 times the stall speed only provides the expected margin from the stall if it is based on calibrated airspeeds. I.e multiply the CAS at the stall by 1.3, and then fly at this CAS. Many airspeed systems under read at the stall. If the IAS at the stall is multiplied by 1.3, one may be much closer to the stall than expected. For example, the POH for the Cessna 182Q that I fly once in a while says the max weight, aft CG landing configuration stall is at 50 KCAS or 38 KIAS. If we fly at 1.3 times 38 KIAS, that is 49 KIAS. The position error chart says that 49 KIAS = 55 KCAS, or 1.1 times the stall speed. Anyone who tried to fly an approach at 49 KIAS would likely get a nasty surprise when they tried to flare.
  4. ASI instrument error and static system position error may be quite different between different examples of the same model RV. I.e. two different RVs flying at the same IAS may actually be at quite different speeds. So, just because an approach speed of XX mph works on one RV, doesn't mean it will work on another one.

It is quite unlikely that very many amateur-built aircraft owners have the means to determine the calibrated airspeed at the stall. So there is no practical way to determine an approach speed that is 1.3 times the CAS at the stall. What is a fellow to do? I recommend the following, based on the flight tests that are used to determine minimum safe approach speeds for both light aircraft and transport category aircraft:
  1. Fly the aircraft enough to have developed a consistent normal approach technique.
  2. Ballast the aircraft to max landing weight at forward CG. Make sure the ballast is well secured.
  3. Climb to a safe altitude, and conduct a series of simulated approaches and landing flares, using the same technique as you would use in a real approach and landing. Reduce the simulated approach speed by a knot or two each time. Note the aircraft controlability at the approach speed, and note the ability to flare. Note the minimum speed where the aircraft has satisfactory characteristics.
  4. Pick a day with very light winds and no turbulence or wind gusts. The best time to find such conditions is right after sunrise, but even then there may be several weeks between days with suitable conditions. Be patient. Don't risk a hard landing by doing these tests on a day with gusts or turbulence.
  5. Fly a series of approach and landings, using your normal approach and landing technique, but reducing the approach speed by a knot or two each time. Pay attention to how the aircraft responds to the flight control inputs in the flare. Note any signs of inadequate control, impending stall, difficulty in obtaining a satisfactory touchdown, etc. As you reduce the approach speed, eventually the aircraft will start talking to you. It will tell you that you shouldn't reduce the approach speed any further, or you will risk a hard landing, etc.
  6. Caution - Don't be too aggressive about trying to demonstrate the absolute minimum possible speed. This path leads to a hard landing, and possible aircraft damage. Stop the investigation when you have a slow minimum speed that allows an acceptable flare and touchdown, using your normal technique.
  7. The following restrictions, from the requirements for type-certificate aircraft, are recommended to ensure that a minimum speed approach and landing demonstration is not a "party trick":
    1. Once the power has been brought to idle, there should be no need to increase the power. By all means, if you need to increase power to achieve a safe touchdown, increase the power. But you should conclude that perhaps the approach speed was too low, and the minimum approach speed should be increased.
    2. The power changes that are made should be the same as would be made during a normal approach and landing. E.g, if a normal approach and landing has the power brought to idle in the flare, it should be possible to do the same during the demonstration of the minimum approach speed.
  8. Add a comfortable increment (perhaps 5 kt) to this minimum demonstrated approach speed, and this becomes your minimum operational approach speed, to only be used in calm conditions. If the conditions are not smooth, add a few more knots, so that as the airspeed bounces around in the bumps, the bottom of the bounces is no lower than your minimum operational approach speed.
  9. Confirm the ability to safely manoeuvre at your minimum operational approach speed by conducting turns at that speed at a bank angle that is a bit higher than the highest you would use in service. You should be able to maintain a stabilized turn without encountering stall warning. Increase the minimum operational approach speed if required to obtain satisfactory manoeuvring capability.
  10. If you have a short field landing technique that differs from your normal landing technique (perhaps you keep power on until touchdown, and use a minimal flare, etc), repeat the above series of tests using a short field technique. You may have different minimum approach speeds for normal and short field landings.
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  #14  
Old 06-16-2009, 03:23 PM
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N941WR N941WR is offline
 
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Kevin,

That is the best read yet on working to determine the numbers that work for each person/airplane.

The numbers I use are based on my phase 1 testing and many flight hours since then.

During my Phase I, I made 7 landings on 8/26/07 and the next weekend, 9/1/07 I made 25 landings. These were not all simple, line up three miles out and grease her on type landings. I worked down below 1.3 x my stall to see what would happen as well has higher speeds. If you haven't done this test, I highly recommend you try it.

Find a long runway, come in fast and watch how far you float before stalling it on. Yes, do full stall landings on each one. Also note your VSI, when the speeds get slow, you probably won't have enough energy to flair and arrest your sink rate. Your butt will tell you when you are slow as it will just drop in. These can be hard landings so be careful.

The other thing I thought was cool was you could feel it when in ground effect and how far the plane would glide in ground effect before stalling.

Just some ramblings as I think back to those early flights.
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  #15  
Old 06-16-2009, 10:52 PM
PCHunt PCHunt is offline
 
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Default AOA

If you really want to fly into and out of short fields, why not get an AoA system? Much more better than the "notoriously inaccurate airspeed indicator."
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  #16  
Old 06-17-2009, 06:53 AM
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L.Adamson L.Adamson is offline
 
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Quote:
Originally Posted by PCHunt View Post
If you really want to fly into and out of short fields, why not get an AoA system? Much more better than the "notoriously inaccurate airspeed indicator."
I can't say how accurate my airspeed indicator is at higher angles of attack, and slower airspeeds; but it's quite consistant. When it hits 55 kias which is quickly with a C/S prop...............then I know that I had better be very close to the runway. But I would like an AOA though.

L.Adamson --- RV6A
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  #17  
Old 06-29-2010, 08:30 PM
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apkp777 apkp777 is offline
 
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Okay, I need to revive this old thread.

I am in Phase I and spent the first 20 hours dealing with engine performance and now I am wanting to focus on my landing technique.

While I don't find it hard to land my -9, I do find it a challenge to replicate the same approach time after time. It seems that 3 out of 5 are consistent but 2 out of 5 are unpredictable. It seems my years in Pipers and Cessna's hasn't served me all that well for my -9. I am trying to fly my RV like a Piper and it isn't working. I am honestly admitting I am currently not an expert on landing an RV and would love some input. I really want to try a bunch of different techniques and see what works. So far having done 30-40 landings, I haven't found anything that I am loving. I did my transition training in an RV-7 with a C/S prop and had not trouble replicating the same approach over and over. What's the trick with the -9 F/P?

I like to hear what guys (and gals) are doing for pattern procedure. Answer any that you wish.

1. How far from runway on downwind?
2. Speed on downwind?
3. A-Beam, what do you do?
4. Flaps, when and where?
5. Square pattern,180 or dog leg?
6. Speeds in the descent?
7. FWD Slip?
8. Those of you that are doing power off approaches, are you concerned about shock cooling (in winter)?
9. C/S or FP?
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  #18  
Old 06-29-2010, 09:46 PM
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Greg Arehart Greg Arehart is offline
 
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Tony,

Here's where I am now after about 230 hours:

1) typically 1/4 to 1/2 mile, depending on conditions. I prefer to fly close patterns and want to always be within gliding distance of the field
2) varies, but I want to be at 100 mph and pattern altitude abeam the numbers
3) pull power to idle, put in flaps
4) as soon as I'm below 100 mph (typically around 95), I put in full flaps (takes a few seconds, of course)
5) usually a somewhat modified square pattern to 180 - depends on lateral distance to runway and crosswind component
6) hold nose up to hit 75-80 mph, trim at 75 (76 is best glide)
7) slip as necessary depending on whether I cut the corners too much etc. Usually I'm right on at my home airport (5000 ft elev) but find that there is too much air at lower altitude and may have to slip to get down but I'm getting better at judging this
7a) I try to come over the fence at about 65 mph with a bit of back pressure so that if anything, the nose will go down rather than up if I let go of the stick
8) I've thought about shock cooling, but from what I've read it's not as big an issue as some people make it out to be. I'm certainly not a mechanic (you are probably better placed than most to make this call) so don't really know whether shock cooling is an issue. I would tend not to pull total power if it is really cold (below maybe 15 F)
9) FP

If I'm trying to land really short, I will come over the fence at 60 mph and can typically put it down and stop (with minimal braking) easily within 1000 ft of runway. On a good day I think I could hit the threshold and stop within 500 ft if necessary (plenty of brakes needed).

Hope this helps

greg
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  #19  
Old 06-29-2010, 10:49 PM
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flyboy1963 flyboy1963 is offline
 
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Default -9a ops

Great points Kevin, and Tony, I have to add one thing.
I too have only 25 hrs and a few dozen landings, so am 'feeling' out the right speeds.
My question is; are full flaps really better than 2/3? If they only lower the stall 1 knot, and max lift is at 15-20 degrees, are we better off to use 20, and then be able to slip with more safety or authority if needed, or accelerate out of a botched flare into a climb?
Just a question, based on some of the opinions that full flap slips are 'bad'.

Testing at altitude has to be the best, and most difficult thing in the world to do! maybe with a safety pilot calling out the descent, while you look out the front pretending to see the numbers. ( where's that synthetic HUD when I need it!?!?!)
I agree that doing a hundred Cherokee 140-style arrivals, (dropping it in from 6' a bunch of times) is not good for the -9 gear or anything else.
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  #20  
Old 06-30-2010, 06:06 AM
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apkp777 apkp777 is offline
 
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Thanks Greg,

I am going to give your technique a whirl. It sounds like you keep in pretty tight. Something that I like. I am finding that it's tough to keep the speeds down. I had been aiming for 65kts, but I think that's my problem. The wing is too efficient at that speed. I will slow it to 60 kts and see how it does. I know its a slightly nose high sight picture, that's where the the difference in airplanes is significant.
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