[acam37]

I'm about to buy an RV-4 project and have talked to several -4 owners here in East Texas. One thing I'm finding conflicting with different owners is how much weight can be carried in the back seat. I spoke with one guy and he told me no one over 170lbs, which pretty much eliminates 90% of the people I know. Another guy flew into the airport one day with a "Bubba" in the back that barely fit and said it flys fine but gets a little squirrely as you burn off fuel. So what is the rule of thumb? pilot experience, pilot comfort zone, or actual weight and balance issues? I'm 6'1" and currently about 250. I sat in the front seat and fit nice, but a little cramped in the back, but not too bad.

 

[ccsmith51]

Rules of thumb?

IMHO, W&B is the ONLY consideration. That means you need to account for EW, GW, fuel, pilot, passenger, and baggage.

For example, on my RV-4 (EW = 998#, pilot clothed 192#):

With full fuel and no baggage I am limited by the 1500# GW to a 118# passenger weight.

I never (intentionally) fly with less than 10 gal of gas. In this case, again with no baggage, I become limited by the rear CG to a passenger no heavier than 186#.

So, my personal passenger weight limit is 180#.

YMMV....

 

[Mel]

Yep!

It's all in the weight & balance, especially balance.

An RV-4 with an O-360 and constant speed prop can carry a larger passenger than one with an O-235 and a wood prop.

Be very carful with aft loaded -4. They can get pretty pitch sensitive, especially at landing speeds.

 

[acam37]

Thanks for the replies. So the RV-4 is basically a single seater with a back seat. None of my flying friends and I do mean none are under 200lbs. So if I decide to get this plane airworthy again, I'll probably have do do some horse trading to move over to a -6 or -7. The last thing I want to do is put myself in a situation I'll regret.

 

[the_other_dougreeves]

I think the size of the -4's rear seat would be kind of self-limiting on the weight. I can't imagine a 200+ pounder fitting comfortably in the back of the -4, so you probably need to upsize to a -8.

TODR

 

[David Paule]

I'm about 5' 8" and got a back-seat ride in a local RV-4. Can't imagine anyone taller than I am fitting in there. It was more of a leg length issue than a torso height issue, and for me that's ironic because I have relatively short legs.

So if you want to carry a passenger, simply find short, cute, light ones.

Dave

 

[rbibb]

I had a 6' blond with 36" inseam length legs in the back seat of my RV4 all the way to Oshkosh and back. The foot wells make a big difference.

It's all about balance. Can get a bit touchy if CG gets too far aft.

Typical RV4 empty wt is 925-950 lbs. Gross is 1500 and fuel is 32 gal (192lbs).

So you have 350 or so for passengers. Of course HW that is distributed is a physical matter that varies by individuals involved.

RV4 isn't made for large people is the net of it. Part of the motivation for the design of the RV-8 I would suspect.

 

[dealfair]

Weight Distribution

It's all in the weight & balance, especially balance.

Be very carful with aft loaded -4. They can get pretty pitch sensitive, especially at landing speeds.

Right Mel,

Shortly before logging in here, I sent Smokey Ray photos of his McKinney pals, Hollywood & Cheese, about to depart 8T6 for T31 in Chuck's RV-4. Hollywood is every bit of 220 lbs., about 5'10" or 11" (the rear seat passenger). Cheese is 6'plus and at least 180. N62CW is an O-320 w/wood FP.

They blasted out no problem and were back at T31 in 2 hours. (350+ miles)

If Smokey sees this, maybe he'll post photos & comment. I'd post them; but I need more training. Apologies to Mike Starkey who's tried to help me.

Mel is correct. Weight distribution (balance) is the key. I've flown with a 6'2" 240 lb male passenger in the back with no problem. Then, on a couple of days, I tried to carry a 5'3" 180lb female and thought I was going to crash & burn. I've commented on it in posts years prior. After my second try with her, I refused to carry her. The male had some of his weight forward, in his legs. All her weight was concentrated in the back and it made a HUGE difference. That moment arm truly means something.

Nowadays, I check out a passenger's physical structure. If you look at Jeff Hanson, Hollywood, he's got muscular legs and puts some of the weight up front. If one puts a bucket butt passenger in the rear, then you'll have problems.

My two centavos. I hope Smokey sees this.

Cheers all,

 

[rjtjrt]

This (fatal) accident report may assist with a decision re W&B.
The accident involved structural failure and loss of tail control surfaces, in what was found to be an aircraft that was built in compliance with design specifications.

http://www.atsb.gov.au/media/24397/aair200701033_001.pdf


"ANALYSIS
With the rear centre of gravity (C of G) calculated to be 97.9 mm outside the limit permitted for aerobatic manoeuvres, positive control about the pitch and yaw axis of VH-ZGH was diminished.
With the C of G behind the rear limit, the moment arm of the rudder would be reduced, making the rudder less effective at stopping the aircraft from spinning. This would be further compounded because the aircraft was overweight, resulting in a higher stalling speed. Recovery from a spin with the C of G so far to the rear of the approved limits (Figure 6) was untested and likely to be difficult or impossible.
The engine was heard to gain power during the spin before the aircraft entered an unstable spiral. This would have caused gyroscopic moments from the rotation of the engine and propeller to be introduced, which may have further inhibited spin recovery.
When an aircraft enters a fast, tight spiral with engine power applied, the aerodynamic and inertial forces acting on the airframe increase significantly. If unchecked, these high structural stresses can rapidly overload the aircraft’s aerodynamic surfaces, leading to eventual failure.
The pilot had conducted training in a number of aerobatic manoeuvres but had not completed the spin recovery training required prior to conducting aerobatics."

"Structural integrity
The structural integrity of the separated tail aerofoil sections (Figure 4) was assessed against the original approved construction drawings. This showed that the tailplanes and the fin and their attachments were compliant with the design specifications."

John

 

[smokyray]

Weight a minute....

Right Mel,

Shortly before logging in here, I sent Smokey Ray photos of his McKinney pals, Hollywood & Cheese, about to depart 8T6 for T31 in Chuck's RV-4. Hollywood is every bit of 220 lbs., about 5'10" or 11" (the rear seat passenger). Cheese is 6'plus and at least 180. N62CW is an O-320 w/wood FP.

They blasted out no problem and were back at T31 in 2 hours. (350+ miles)

If Smokey sees this, maybe he'll post photos & comment. I'd post them; but I need more training. Apologies to Mike Starkey who's tried to help me.

Mel is correct. Weight distribution (balance) is the key. I've flown with a 6'2" 240 lb male passenger in the back with no problem. Then, on a couple of days, I tried to carry a 5'3" 180lb female and thought I was going to crash & burn. I've commented on it in posts years prior. After my second try with her, I refused to carry her. The male had some of his weight forward, in his legs. All her weight was concentrated in the back and it made a HUGE difference. That moment arm truly means something.

Nowadays, I check out a passenger's physical structure. If you look at Jeff Hanson, Hollywood, he's got muscular legs and puts some of the weight up front. If one puts a bucket butt passenger in the rear, then you'll have problems.

My two centavos. I hope Smokey sees this.

Cheers all,

Thanks Deal, Cheese, Wood and I all built our 4"s before the pre-punched RV world existed. Times have changed, now anyone can plunk down 40 Grand and get the RV grin. What they don't get is knowledge and design intuition from building, experimenting and test flying.

Technically, every RV flight is a test flight.
The RV4 was never designed for hauling large individuals or freight aft of the roll bar. Van basically designed a "bigger three" to appease demand for the wives to travel along with their RV3 husbands. As Mel said, its all about CG and W&B. For those of us out there that actually built a Four, the plans have very specific guidelines for passenger hauling, CG and aerobatics. I set my limit at 200Lbs total aft of the roll bar at full fuel load. (0-320/Catto) Your mileage may vary...

RVs are experimental (surprise surprise) and every one is unique. Make sure you stay within the envelope for your airplane, aft CG 4"s become a handful(pitch sensitive) at low speeds. If you load anything in the back seat larger than girls or kids, be wary.
Acam(Arlie) If you only have big guy friends, maybe you should look at the RV6, 8 or 180CS RV4"s only. (Or find a cute girl to fly with you )

V/R
Smokey

 

[WAM120RV]

I like it!

Smokey,

I like the way you have put this .... very diplomatic but with a cheeky grin. Personally I felt a bit insulted when it was suggested the RV4 was a single seater......... well I guess it is if you require two seats to sit down

 

[smokyray]

Changing with the times...

Smokey,

I like the way you have put this .... very diplomatic but with a cheeky grin. Personally I felt a bit insulted when it was suggested the RV4 was a single seater......... well I guess it is if you require two seats to sit down

Thanks Steve,
The farther my Fighter Pilot past gets behind me, the more diplomatic I seem to have become...scary.

When I was flying my Harmon Rocket I stopped through Bakersfield to eat at John Harmon"s restaurant on the field. He was there and sat down with my wife and I. One of the questions I asked him was "why" did you build the first HR2? His answer? "My wife felt cramped on long trips in our RV4." So I drew a chalk line on the hangar floor with the dimensions I thought a "big RV4" should have and accommodate an IO540". The result was historic.

Rumor has it that Van took a tape measure to an airshow where the prototype HR2 was parked and took some measurements. A few months later the first RV8 prototype was unveiled.
If you measure the 2 airplanes dimensions they are very close....

V/R
Smokey

 

[acam37]

Thanks guys, you pretty much confirmed what I already knew. I just needed to hear it from an unbiased source. Maybe it was wishful thinking that I could fly the -4. The purchase is basically a done deal. The initial reason for buying this plane was to get it flying again and sell it for a bigger RV. My partner has been trying to convince me to keep the -4 because it would suit his needs almost perfect. But from reading these posts and doing more research this would be foolish on my part. I need an RV-? That can carry a passenger with a little meat on his bones. I think a -6 or -7 is more suitable for me.

 

[dealfair]

I need an RV-? That can carry a passenger with a little meat on his bones. I think a -6 or -7 is more suitable for me.

You've made a wise decision for loads like that. Don't look back & enjoy your flying Arlie.

Best to you,

 

[Bill Phillips]

Buy a RV-8

Go buy a RV-8 or A, put a big 200 hp mill in the front with a CS metal prop, then you can fly 260 pound Buds in the back and not worry much about it. My limit is right under 270, Best regards,
Bill Bluebird RV-8A