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Landing an RV-4 with a rear seat passenger

P

PGLong

Member
Help.......I have an RV-4 and am experiencing landing problems with a rear seater present. I installed a Landoll Harmonic Balancer and according to weight and balance, should be able to tote a 225 pounder and stay within CG limits with correct fuel loads. Even with a 120-150 pound person in the rear seat, the elevator controls are so light it's almost like moving nothing. Not sure if I'm over controlling, but it is so easy to get a hip hop dance down the runway. Friend said to try and use a significant amount of down elevator trim to help. Haven't tried that yet but will next flight. What works for others? Just stick with wheel landings? Lots of friends that would like a ride, but hate to threaten them while I learn new techniques.
 
Practise.....

Hi Pat,
A back seater moves the CG back a lot because of the distance behind the CG. It's something that'll take some getting used to but also beware of an increased tendency to groundloop. This is also because the aft CG condition making the distance between the CG location and the contact point of the main wheels further apart.

I'd take some lighter (and probably more attractive :) ) back seaters and slowly work up to the heavier ones as your experience level increases.Stay on your toes,

Regards,
Pierre
 
PGLong said:
Help.......I have an RV-4 and am experiencing landing problems with a rear seater present. I installed a Landoll Harmonic Balancer and according to weight and balance, should be able to tote a 225 pounder and stay within CG limits with correct fuel loads. Even with a 120-150 pound person in the rear seat, the elevator controls are so light it's almost like moving nothing.
Click to expand...
The aft CG limit should be set to where ever your flight testing shows it needs to be. The number from Van's is just a recommendation. There are valid reasons why Van's recommended aft CG limit may not work for you, with your current weight and balance data:

1. The weighing may have been done incorrectly, so you have the wrong empty CG. E.g., the aircraft may not have been correctly leveled. Or the scales may not have been accurate, etc. If your aircraft has an inaccurate empty weight and/or CG, the calculated CG limit (based on the inaccurate starting point) will need to be different than if you had an accurate starting point.

2. Your aircraft may have some difference to a standard RV-4 that could degrade the handling at aft CG. Extra power degrades aft CG handling. Extra friction in the controls may degrade aft CG handling.

3. Each pilot will have a different threshold at which he will declare the longitudinal stability is no longer acceptable. Maybe your personal threshold is set differently than Van's threshold.

Flying with a passenger is not the best way to open up the aft CG envelope. This is something to do with ballast to simulate a passenger. Move the CG back in nice easy steps, adding a few pounds of ballast each flight. Assess the static and dynamic longitudinal stability, with flaps up and flaps down, at idle power and with full power. Do stalls, wings level and in a 30 deg bank turn, with idle power, and with high power. Do takeoffs and landings. Determine where you consider the aft CG limit should be. If that doesn't allow enough weight in the rear seat, then look at what changes you can make to the aircraft to move its empty CG forward.

But first, maybe review the weight and balance. Did you do the weighing? Was the aircraft properly leveled? Did you properly account for the tare weight (chocks, shims, etc)? Were accurate scales used? Check the calculations. If in doubt, weigh the aircraft again.
 
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Not right....

This doesn't sound right at all. My 4 is 964 empty wood prop/320. I routinely carry 180-190 lb passengers, as do many others. I do use a tad more nose down trim for landing, but the overall handling is perfectly normal including stalls.

I don't want to sound alarmist but this sounds like something is seriously amiss.

Aren't there some RV CFIs out that way ? Maybe you could find one to eval the handling of the plane. There's no substitute for having an experienced local RV guy assess this.

John
 
It's all in what you get used to.

I've been flying my -6 for many years with no problems. Most other experienced RV pilots have a problem landing my airplane until they get used to it.
 
This is completely normal for a -4 and a new -4 pilot, when I was new I had the same problem. I flew the -4 for about 10 hours before taking my RV rated CFI for a ride and was surprised how my great landings turned to **** with the weight in the back, I learned to use down trim to keep some pressure on the stick, this works famously and as I get used to the plane I am using less down trim and keeping the stick lighter then I needed to before and taking heavier loads. The -4 is two different airplanes, one solo and one with passenger and or baggage, both planes fly very well but you need to learn how to fly both. If you think you know how to fly the -4 with say 40 -100 hours your dreaming just like I was at that point, I am a very quick study all things with wheels and or wings and am still learning the -4 with 500 hours, looking back I did not know much at 40 hours but I was probably safe to fly with. The -4 like?s wheel or three point landings but tends to settle to a three point quicker with a passenger so you often get a three point with a passenger, if you have short legs this will not be a full stall and if it is it will be ruff.

All this means is learning to fly the -4 well is a hole lot more gratifying then learning to fly a spam can and the result is a hole lot more performance and a plane that goes where you point it.
 
I set a weight limit in my back seat at 180 lbs. My CG calculations say I could carry a heavier passenger. It just doesn't feel comfortable though. I picked 180 lbs because that's how much my brother weighs and he's the heaviest person I've taken for a ride so far. What others have said is right though about almost any tandem airplane. They feel like a different airplane with someone in the back.

It's also one of the reasons I'm building an RV-7 now. :)
 
Pitchy 4

Hey Scott, hope you remember me, I think I gave you your first ride in a 4, anyway, my 4 was pitch sensitive with a rear passenger, I think that it was just somthing I put up with and knew was there and flew more like the helicopters that I fly. Then I changed the .016 elevator skins to the .020 and the pitch sensitive problem went away, even in cruise it seemed much more stable. I do agree with one of the previous posts that if your controls are stiff or have slack in the movement it will enhance the problem. If you wish to fly up to RIU some morning I would be glad to look at it for you.

Randy
 
New RV-4 owner landing with passenger.

I've been searching through the Forums for info on RV-4 landing w/passenger. I know it's much different than any of the other RVs so I'm looking for additional input from -4 drivers.

I now have about 7 hours in the -4 with my instructor in the back (he's approx 170 lbs and I'm 195 lbs) and find 3 point landings challenging so far (this is a short gear -4.) My 3 points seem a bit smoother on grass but so far they feel a bit rough on pavement (and usually the tail hits first.)

How many of you -4 pilots use 3 point vs wheel landing? Are you short gear or long?

Any RV-4 specific assistance will be appreciated.

Thanks in advance,
Stan
 
3pt a challenge for me

Have about 10 hours on my new to me 4.
And I find 3pt landings solo a challenge and have not been able to consistently pull them off.
Wheel landings are coming together pretty well and consistent.

Have had some other RV guys at the airport mention they thought 3pt's are easier with someone in the back.

I do not know yet, have not thrown someone back there and tried it as of yet.

Good luck!

Chris Olsen
RV-4 @ KAEG
N2ZK
 
I have about 200 hours on my -4. I worked up progressively with ballast and found that 225 in the back is a comfortable limit. I have a friend who is 6'3" and 225 in the back a few weeks ago. We flew for about an hour and he was surprised by how comfortable he actually was. Must have looked comical though with us piling out because I'm 6'2".

I don't 3-point with a passenger. I practiced with with Ballast and find that doing a wheel landing just works a lot better for me. I keep the speed up to between 65 and 70kts because the tail will drop a lot faster.

As stated many times on here. Each aircraft is different so use ballast and work your way up incrementally. Keep in mind the baggage as well. My 225lb limit is with absolutely nothing in the back.
 
I agree with both Kevin and Russ. I had a little over 1150hrs in my 4. One of the tricks I used when carrying someone into a normal strip was to carry an extra 10mph in the pattern and wheel land the airplane. It will wheel land very nicely even with a passenger. You didnt mention what kind of speed you were carrying on final. I would be carefull about getting to slow at low altitude when ridding on the aft edge of the CG.
Ryan
 
I have about 300 hours in my RV-4 with the short gear. It is a 320 with a wood prop, 965 empty weight. Solo 3 point or wheel landings are fine. With a passenger I only do wheel landings. I have carried a 215 lb passenger which with full fuel put my CG at 76.2 and GW at 1557 lbs.
 
I normally do three point landings (short gear), just easier for me with or without a passenger plus I like the lower airspeed on touchdown (5kt difference). Wheel landings are easier solo. When solo I need full up trim from the time I pull the power on my downwind turn to base but when I have a passenger I don't need to touch the trim at all. I have flown it with passenger and baggage the last two years to OSH with 1" aft the CG limit in landing weight (fuel burned off), couldn't tell the difference and it required no additional up-trim. The heaviness of my elevator is pretty consistent in any weight and CG on landing.
 
I'm a buyer not a builder and have been nervous about taking a passenger because of the expectation that "its a different aircraft".

I'd like to do the equivalent of Phase 1 CG testing.

What do people recommend for "ballast" ?
 
humptybump said:
What do people recommend for "ballast" ?
Click to expand...

Lead shot is probably the best way to do it if you have access to a couple hundred pounds in little bags. I have also used 50 lb bags of sac-crete, but it is dusty (and the dust can be corrosive). In a pinch, buy a few cases of oil - you can put a few in the baggage compartment of an -8 and get more moment way back there than putting weight in the seat.

Paul
 
keep in mind as you burn fuel, the situation gets worse.....you may not be able to take this 220# passenger on a 3hr flight where you land with 1hr of fuel left.....be sure to consider this when you put a heavy person back there
 
1200+ hours now.

First I am curious whatever came of the original poster Pat Long, it looks like he has never responded back to let us know how he is doing with his RV-4. So Pat if your still hear how are you doing?

Randy said in post #8 that changing elevators changed the pitch feel of his -4, I would just bet that it’s not the skin thickness that made the difference but rather the radius of the trailing edge of the elevator and how flat the skin is ahead or the trailing edge, this is one place that can vary widely from one RV to another giving different pilots of what seems to be the same airframe very different results. I believe a sharper radius will result in the aircraft being heavier in pitch wile a wider trailing edge will make it lighter in pitch, a concave skin ahead of the trailing edge will make it heavier and convex will be lighter.

If wheel landings work for some pilots wile carrying a passenger then stick to what works, no argument here, not trying to change anyone’s mind. Mechanically speaking wheel landings should be harder with the CG aft, the further aft the CG is the more the airplane wants to pitch up when the wheels touch the ground. If all three wheels touch the ground at the same time or the tail wheel touches just ahead of the mains then the airplane can’t pitch up and tends to then stay on the ground. For me it’s a three point every time with a passenger:)
 
One more thing.

Depending on your prop, mine is a constant speed, (fixed pitch may not be so much of an issue) carrying just a little power to touch down slows down the process of deceleration in the flair giving a little more time to get it on just right before it stops flying.
 
Ironflight said:
Lead shot is probably the best way to do it if you have access to a couple hundred pounds in little bags. I have also used 50 lb bags of sac-crete, but it is dusty (and the dust can be corrosive). In a pinch, buy a few cases of oil - you can put a few in the baggage compartment of an -8 and get more moment way back there than putting weight in the seat.

Paul
Click to expand...

I was thinking of using a plastic can filled with water to try this out.
Take the seat bottom out in back and strap it down.
Anybody see a problem with that ?

Thanks
Chris Olsen
RV-4 @ KAEG
N2ZK
 
Russ, good call on the trailing edge. I am actually building new elevators for just this reason. The original builder pinched them too much. I asked Van's about it a few months ago and they immediately indicated that was the likely culprit which I hadn't thought of prior. I flew my buddies RV4 that had a larger radius trailing edge and the elevators were significantly lighter in pitch.
 
Weight a minute...

Pat,

Several 0-320 wood prop RV4 landings over 20 years taught me a couple of things:

1. If pax over 150 Lbs, make sure you have full fuel, makes a difference.
2. I always wheels-land 5 knots fast 70KIAS (runway length available)
3. Have a weight cutoff you won't exceed, I used 200 lbs max weight aft of the roll bar.
Practice makes perfect.

V/R
Smokey

PS: More aft CG=Lighter stick force per G. Basically you will over control in pitch if you're not used to it, as you found out. The HR2 solved this problem by bolting an IO-540 out front, 300 pounders in back didn't phase it. Note: I recommend taking girls vs guys for rides, more fun, lighter and cuter :)
 
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-4 passenger observations

I have been flying my-4 a little over a year (120hrs.), and first passenger ride was at 40.1 hrs on hobbs. I almost always have a passenger these days, as folks love flying in the -4. I did 2 tests with "weights" in back, simply using gym weights in a heavy duffel, secured by the harness. First was with approx 75 lbs, 2nd with 150 lbs. To date, heaviest passenger has been 220, and I had half tanks of fuel. The weight tests simply show the pitch force difference, and one must expect a lot of forward stick to get the tail up on T/O roll. The most noticable safety factor is the very light pitch control in an aft CG configuration...very easy to over control flare or zoomy manouvers. I like to 3 point with pax, as it seems to settle in nice and I like slower on my less than perfect runway. I do have the long gear, and all 3 touch about the same time. I do hold an extra 5 knots in the pattern .
 
Looks like Pat Long has sold his RV-4

http://www.vansairforce.com/community/showthread.php?p=268660#post268660

Still a good discussion though.


Also my Dad was mentioning something I also do and learned way back as we probably all learned during our primary flight instruction, that is to park at the end of the runway or parallel taxi way and observe the picture down the runway over the nose, then during landing hold that picture tell it touches and if you did it right all three will touch at the same time. I think this is the most accepted method for landing any airplane and using it we all should be able to 3 point an RV-4 on command with a little practice.

For a nose dragger you would just hold the nose even or just above the opposite end of the runway but this thread is about tail draggers.
 
sand

60-lb sacks of sand are less messy than concrete. I put them in Hefty trash bags to prevent spilling sand in the airplane. I tested with one, two, and three bags of sand, Then I put a case of oil in the rear baggage and repeated.
 
Wood pellets for ballast

I used 40 pound bags of wood pellets for CG testing in my RV-8. I put each bag in a plastic garbage bag to contain dust and stacked them on the rear seat floor and secured them with the seatbelts. Worked well.

Dan Miller
RV-8 1100 hours
 
rear seat passenger

Hi,
I am learning to fly an -8 and struggling with the same issues. I'm using the the gradual method. Have added weight to the rear baggage compartment, and the passenger seat, but would like to build up to taking a large rear passenger, 210 lbs (my husband). Keep me posted on your progress.
Barbara
 
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