Weight in the Rear (passenger) seat

Hello everyone and thank you for your time. I'm looking at purchasing an rv-4 in the near future and I'm 230lbs... 6'3". I'm looking at how much weight I can put in the rear seat in the form of a passenger... I'm losing weight by working out now... so I should be down at 200 shortly.... or less. How heavy a person can I put in a 1990 model rv-4 with the short gear? How much does the book say and how much can you put back there and still be safe. AND... how tall can the rear seater be?
I appreciate your comments and knowledge.
Thanks
Brian Wallis
(I looked on vans site and did not see the answers) ps.. I know it will be tight but the owner is the same height and I believe about the same build and he does fine.

Brian, I ride in the back of Wicked Stick's -4.

W&B-wise, we would be better off if he rode in the back but it works out fine.

He is about 175 and I am 194. It takes VERY LITTLE stick motion for a good pull-up!

He can still nail a wheelie landing with me back there but the tailwheel really bangs around while on the taxiway.

Honestly, someone any larger than me WOULD NOT be happy back there!

As it is, body parts go numb when I am back there!

I am guessing that when you get down to 200, a 175 pounder would be the most you would want to leave the ground with. Your CG would be really nice that way too!

Do cardio AND resistive weight training! Eat right!

Hope this helps!

CJ

About the same

I have a similar wood prop RV4. I'm 180 and a 190lber in back will put me a hare over gross weight. The sensitivity in pitch is noticable in slow flight much more so than in cruise. Nonetheless, it is quite managable IF you stay inside the CG envelope.

Take a look at the W&B tables on Dan Checkoways site. Van set the gross weight at 1500lbs for the RV4. Many people set them much higher. It's pretty hard to load the airplane outside the envelope if you stick to 1500 lbs gross. I would really be uncomfortable flying a 4 that is loaded beyond the back of the envelope.

If you are looking to buy one, do some searching on this site and the RV-List. You can get a pretty good education for your time investment. They are wonderful airplanes for sure. But they are not all things to all people.

Good luck and don't hesitate to ask questions here. There are lots of people ready to help you in your search.

John

Then again.........

Remember, Jon Johannson puts 300 lbs of fuel in his back seat.......and Van said it was okay.

Regards,

Im 200 and Ive done 220 pax in a RV-4 light fuel and full.. It doesnt fly great(pitch sensitive) but its doable for running around the patch.
Good Luck,

pierre smith said:

Remember, Jon Johannson puts 300 lbs of fuel in his back seat.......and Van said it was okay.

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There is a difference between how much weight the rear seat structure can support, and how much weight puts the CG too far aft. I believe Jon's RV-4 had a metal prop, a header tank and more weight than normal in the instrument panel. Jon also looks to be lighter than most of us. All these things would move the CG forward, helping compensate for the fuel in the rear seat. According to his book, the CG was within the recommended envelope, even with the rear seat tank full.

Every aircraft is different. Just because one RV-4 can be flown with XXX lb in the rear seat without going aft of the recommended CG limit does not mean that the same would be true with another RV-4.

Aircraft handling degrades significantly as the CG moves aft. The aircraft will become more sensitive in pitch, and more difficult to trim at a desired speed. If the CG moves too far aft the longitudinal manoeuvring stability will become negative (i.e. if you pull some g, the aircraft will want to pitch up, and you'll have to push forward on the stick - a recipe for an overstress). Move the CG a bit more aft, and the static longitudinal stability will become negative (if you trim at a given speed, and slow down, you'll have to push forward on the stick to stabilize at a lower speed - not good). At some point the stall recovery may be affected. Same with spin recovery.

I would not fly with the CG aft of Van's recommended limit without doing a lot of testing using ballast. You would want to move the CG back a bit at a time, doing several flights at each CG, to see at what point you wanted to call the aft CG limit.

Don't fly with a passenger at any weight and CG that you haven't done first solo, using well secured ballast.

Great Plane...

I'm with Kahuna on this one...I believe the RV-4 is under utilized and under appreciated what with all the 'newer' Van's products. Equipped properly it can do remarkably well, including cross country! I am a shade over 200#s and 6'1" and have flown my -4 to OSH numerous times with back seaters and luggage for a week-NO PROBLEM (I will not tell you my wifes weight but we had 50#s in luggage). If you have rear footwells and a metal prop (and other easy mods), there really is little limits to a creative pilot in command.

FYI, while the Van's gross weight limit should be observed and the aft CG limit worshipped, I have had a 6'3" 250# in the back and the plane flew fine, as mentioned earlier the pitch sensitivity is affected (beginnings of reverse command!) and care should be taken to avoid slow flight/stalls, but again, not a problem with a wise/creative PIC.

Finally, I sold my -4 to a patch wearing USAF test pilot who flew his new -4 in a full up test profile graduating his weight in the back seat using weights he would transfer from the front seat to the back, then do slow flight, stalls and spins. Long story short, I have always had a great respect for the -4 but now believe it is near idiot proof. I say NEAR because we continue to improve the idiots.

The RV-4 is a stronger plane than the -8. I've owned both and from my perspective, the -4 is a better flier too.

Be safe, but don't listen to old pilot tales, explore yourself, talk to people who have REALLY owned one, and be creative....the -4 is the best deal for the money!

Jj
Building RV-4 fastback
RV-6
YAK 50
RV-8 SOLD
Rocket SOLD

C of G

Kahuna said:

Im 200 and Ive done 220 pax in a RV-4 light fuel and full.. It doesnt fly great(pitch sensitive) but its doable for running around the patch.
Good Luck,

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I've done the same....I am 180 and had a 245#er in the back......I was still within limits but not by much and although OK for around the patch it was a little (OK a lot) more pitch sensitive. ......Crosscountry...no way, you'd be landing to fill the tanks every hour to keep the CofG within limits....As Smoky Ray has said ....."cute girls under 125 lbs only"...

Brian,
Another thought..... If you're rather tall, or have long legs, you may also want to crawl into an RV-4 cockpit and check out the leg room. They are all slightly different, but you can get a sense of dimensions. Unlike the 6 and 7, which have different piano hing locations to adjust the seat, it's not so easy in the 4. I have a good friend who is looking for a 6 only because he doesn't fit in my 4. All that said, I've flown the RV-6, 7 and 8 and when I crawl back in my 4, I love it even more. There is no doubt that the 4 is the most agile flying machine.

RV-4 Ever!

Brian,

You have chosen wisely, the RV4 is the best bang for the buck. The only better RV is the Harmon Rocket, and it IS an RV4. I started flying my RV4 in 1996 and have amassed 1500 hours on her and have given alot of rides. I have progressed from a unpainted 925# 150HP wood propped airplane to a 975# 175HP MT prop jewel of a sportplane. You have to consider whether your RV4 has a light nose or not. 50# tailwheel weight empty is a good number to start with. The 180 C/S RV4's I have flown have less aft CG issues than the wood propped 160HP airplanes. I installed a Landoll Harmonic dampener on the flywheel to add 10lbs on the nose and installed a Odyssey battery on the firewall. All of this helps but the bottom line is stick forces per G.
All said, I use 200# max aft of the roll bar for my round number with <1/2 tanks. Any more and I go with full fuel. The biggest dude I hauled was a 220lb guy. Ran out of forward trim in cruise but otherwise non eventful. Remember, 2 guys in CO were killed doing a spin in an RV4 in the early 90's, the back seater over 200#. Keep in mind with aft CG goes aft CG stall characteristics. If you want unlimited back seat, buy a Harmon Rocket, mine has a 300# aft limit.
Like I have said many times, the back seat was designed for cute, small girls, not fat, hairy guys. Your preference?

Rob Ray
RV4 (built when dinosaurs roamed taxiways)
HR2 (almost as good as sex)
F16 on weekends...(top of the list of cool)

Haller

Dave,
Check your PM's,
Regards,

So i have been reading through these posts and i know no one has said anything in this one for quite some time but i had a few questions. Everyone is talking about the rear passenger but what about PIC, is his weight as not much a factor? I could probably figure it out but i dont have a W/B or CG chart. I ask this because I am as well looking into getting a -4 with my 2 roomates and i am the biggest of all three at right around 200pds. they each are closer to 150pds. We are looking to use it as a X-country plane as well as just local flights. What do you guys think? Should we be alright??
Thanks alot
David

Flyguytki said:

Everyone is talking about the rear passenger but what about PIC, is his weight as not much a factor? I could probably figure it out but i dont have a W/B or CG chart.

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Let's go back to basics. If you add a weight to the aircraft, the effect it will have on the CG depends on where you add this new weight. If the new weight is ahead of the CG, the new CG will be ahead of the original CG. If the new weight is behind the CG, the new CG will be behind the original CG.

The amount the CG moves will depend on the amount of the additional weight, times the distance from the original CG to the location of the new weight. With an RV-4, the pilot's seat is a bit behind the CG, but it is not nearly as far behind the CG as the passenger's seat. So adding the same amount of weight at the back seat will have more effect on the CG than adding the same amount of weight at the front seat.

Every RV-4 flight will have a pilot in the seat, so if we talk about a heavy pilot, we are only really talking about the difference in weight between an average pilot, and our heavy pilot. In your case, if we use the FAR std weight of 170 lb, this is a 30 lb extra weight in the pilot seat, which has a small effect on the CG, as compared to what it would be with a 170 lb pilot. But, if we put a pax in the back seat, the CG will be affected by his whole weight - big effect.

Bottom lines: 1. calculate your CG if there is any question.
2. A heavy pax has much more effect than a heavy pilot, on the tandem seat RVs.
3. Heavy baggage in the baggage compartment is even worse than a heavy pax.

Gosh just be careful, respect CG

Gosh just be careful and watch CG, especially if you plan on doing acro. All I can say is respect it. Frankly its almost impossible to get under Acro weight and CG sometimes, espcially if you are a duce, but it depends on the planes empty weight. Most planes are overweight as well as the pilot (me included).

I sold by RV-4, but I was caught by surprise the first time I flew passengers. Even after that I was always impressed how light the pitch controls got.

I flew extensively with the girlfriend and camping gear, and was near the aft CG, past acro CG for sure. However I had a constant speed prop with the longer hub, which put my solo CG on the fwd limit. Any way it was fun and safe and had no problem, but than I would not dream of doing acro at those weights and CG's.

Stick forces get crazy light with aft CG, which can cause all manner of problems like pulling too many G's when maneuvering (if you are not ready) or over flaring on landing. Actually with a heavy passenger on landing with full nose down trim I almost had to push slightly forward to flair properly. Lets just say the stick force where super light.

There was a recent RV-4 accident in Australia with two fatalities. The report was detailed and they determined it was not only over gross but aft CG. It seems like this contributed to the accident.

Gosh just be careful, respect CG

Gosh just be careful and watch CG, especially if you plan on doing acro. All I can say is respect it. Frankly its almost impossible to get under Acro weight and CG sometimes, especially if you are a deuce, but it depends on the planes empty weight. Most planes are overweight as well as the pilot (me included).

I sold by RV-4, but I was caught by surprise the first time I flew passengers. Even after that I was always impressed how light the pitch controls got.

I flew extensively with the girlfriend and camping gear and was at aft CG and gross. I had a constant speed prop with the longer hub, which put my solo CG on the fwd limit. Any way it was fun and safe and had no problem, but I would not dream of doing acro at those weights and CG's. Acro weight limit is a pain to observe with the RV-4 and RV-6 because the acro weight is low. A heavy empty weight and/or pilot makes dual Acro basically a no-go, at least if you want to observe Van's recommended limits.

Stick forces get crazy light with aft CG, which can cause all manner of problems like pulling too many G's when maneuvering (if you are not ready) or over flaring on landing. Actually with a heavy passenger on landing with full nose down trim I almost had to push slightly forward to flair properly. Lets just say the stick force where super light.

There was a recent RV-4 accident in Australia with two fatalities. The report was detailed and they determined it was not only over gross but aft CG. It seems like this contributed to the accident.

I highly recommend you re-weigh you RV-4. It is well known that used RV's have notoriously inaccurate W&B.

AND

Most of that "GAINED" weight is aft of the CG!

I was caught by surprise the first time I flew passengers. Even after that I was always impressed how light the pitch controls got.

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Don't do anything with a passenger on board that you haven't already done solo. For example, before flying with a passenger, you should fly with ballast so that you are at the same weight and CG that you would have with a passenger. Investigate static longitudinal stability (trim at a speed, then see how the stick forces vary as you stabilize at a different speed without retrimming, then see if the aircraft will return to the trimmed speed if you gradually reduce the stick force), stick force when manoeuvring, stalls, aircraft pitch response during approach and landing (starting with simulated approaches and landing flares at altitude, then doing real ones to a runway), aircraft pitch response during a go-around, sideslips, etc. This is the sort of stuff that should be investigated during the flight test phase, or in the first few hours that you fly a purchased aircraft.

No Passenger, No Problem

Dave Dollarhide said:

...There is no doubt that the 4 is the most agile flying machine.

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Well, except for the 3, and you don't have to worry about passenger weight in it.
Now if I can only learn to land less than twice per takeoff!

...Joe

Watch the paint.....

It's been said that paint is for houses but a polished airplane is a real PITA to maintain. When you paint the airplane, remember that around 75% of the painted area is aft of the CG so apply it lightly from the spar back. As was said earlier, the heavy airplanes usually have a rearward biased CG. Paint can add 30 lbs or more and most of that will be behind the CG.

Regards,
Pierre