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  #1  
Old 07-07-2018, 02:05 PM
berniematic berniematic is offline
 
Join Date: Nov 2014
Location: Poysippi, WI
Posts: 15
Default Weight in back ?

Hello -
I'm considering the purchase of a 4. I have little - make that no - experience with them. One thing I've been told is weight and balance can be tricky. Plane weighs about 1000lbs. o-360 and metal prop on the front. What should I expect for the max weight for a passenger, with nothing in the baggage compartment?
Thanks.
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  #2  
Old 07-07-2018, 04:08 PM
Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
Posts: 225
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You will need to run the W&B for your particular airplane, pilot weight and fuel load scenarios. Maybe some -4 drivers can give you an estimate, but it will be just that.
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Jake
RV6 completed 1991 sold.
RV7 #72018 N767T first flight 11/21/2017 170+ hrs.
IO-360M1B MT 3 blade, Dual AFS 5600.
1941 J3 Cub skis floats.
2019 dues gladly paid.
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  #3  
Old 07-07-2018, 04:16 PM
Steve Barnes Steve Barnes is offline
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 545
Default W&B RV4

My RV4 was 980# 0320 and CS up front. Plane sold and don't have my W&B numbers anymore. I could carry a 220# passenger, no luggage and I was fine. When I added a CS prop to the plane it changed the CG a lot.

Steve

Last edited by Steve Barnes : 07-07-2018 at 05:11 PM. Reason: wrong weight. Said 1080# by mistake actually 980#
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  #4  
Old 07-07-2018, 04:47 PM
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n82rb n82rb is offline
 
Join Date: Jan 2007
Location: fort myers fl
Posts: 732
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I have a 360 with constant speed. I can go up to almost 300 in the rear. However, I never would. With my 230lb son in the back it is real twitchy.

You will need to run the numbers on each plane, they very a lot by equipment and equipment placement. The more weight in front the more you can put in back. Prop type and material, battery type and location, starter type, mags or electronic all make a big difference.

Bob burns
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  #5  
Old 07-07-2018, 04:47 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,158
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http://www.vansaircraft.com/public/rv4specs.htm

1080+192(fuel)+220(passenger)=1492 lbs, without a pilot.
Were you a newborn at the time? ;-)

Van says empty weight should be 905-913. Admittedly, not many even come close to that, so unless someone used a higher number for gross weight when they got their a/w certificate, plus-sized passengers are going to be a problem from a legal standpoint, if nothing else.

I've owned two -4s; the 1st was 930 empty, and the current one is around 910. Both are O-320/wood prop a/c. Back when I'd just bought the 1st one, with only a few hours in it (lots of T-18 & Swift time earlier) I unknowingly took up a 235 pounder (he was...densely packed). Let's just say it was an adventure, getting it back on the ground. I was never in doubt that I'd get it right eventually, but he sure was, and he had been a back seater in F-4s.

Since then, with a lot more experience, I've flown several 200+ lb passengers. But absolutely no acro, no short strips (for takeoff), and caution on landing. With that much weight in back, the wood prop versions change from being pussy cats to demanding respect. Pitch forces get a lot lighter, even in normal flight. The 360 & metal prop will obviously help CG, but really eat into gross weight.

If you ignore the legal implications, and you're a good stick (in *that* plane; I've had a Marine fighter pilot scare me in the -4), then it will fly with 200 lbs in back. If it's a c/s prop, that obviously helps with takeoffs at high weights.
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  #6  
Old 07-07-2018, 08:26 PM
Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
Posts: 225
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I recently looked at a -4 for a friend that was originally certified at #1500 gross. Over the course of 15 years the gross weight had arbitrarily been increased to #1600 and then #1700. All of this was done merely by the stroke of a pen. Experimental or not, this is totally illegal and unsafe! As others have stated, they become very twitchy (unstable) in the pitch axis as the CG moves aft. If you are the least bit skeptical about the W&B numbers on a particular aircraft, then have it weighed. They all seem to gain a few pounds over the years, but a glaring discrepancy should raise a big concern.
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Jake
RV6 completed 1991 sold.
RV7 #72018 N767T first flight 11/21/2017 170+ hrs.
IO-360M1B MT 3 blade, Dual AFS 5600.
1941 J3 Cub skis floats.
2019 dues gladly paid.

Last edited by Jpm757 : 07-07-2018 at 08:37 PM. Reason: Addition
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  #7  
Old 07-08-2018, 12:54 AM
berniematic berniematic is offline
 
Join Date: Nov 2014
Location: Poysippi, WI
Posts: 15
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Thanks much!
I realize W&B calculations are necessary. I would not fudge the numbers and want to fly me and anyone else safely. So - I was looking for some idea of how they fly from those who know. Certainly appreciate your help.
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  #8  
Old 07-08-2018, 07:35 AM
fixnflyguy fixnflyguy is offline
 
Join Date: Jan 2006
Location: Winston-Salem, N.C.
Posts: 934
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Setting aside all the WB, gross weight numbers and such, I can say from my experience in my -4, when you have a heavy back seat passenger, you need to learn the light pitch control inputs, as aggressive pulls in flight will easily over G the airframe, and when slow/landing one can end up nose high very quickly. I have a personal limit of 200lbs for a pax, but also have smoke oil tank behind.
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  #9  
Old 07-08-2018, 07:39 AM
foka4 foka4 is offline
 
Join Date: Jul 2009
Location: Ankeny, IA
Posts: 209
Default My experience

I put 500 hours on a -4. In my experience, the Vanís published range is a pretty solid guideline to stay within. The handling feels best at the aft end of the range, but at that point, youíll notice that not much rearward stick pressure is required in the flare.

Push the CG back any farther, and youíll be pushing the stick forward in the flare, which puts you in a pretty narrow window of controllability.

When loaded with aft CG, I always found it best to use little or no flaps and land in a full 3-pt attitude (or even tail first).

I think the long gear setup is a slight advantage in tolerating aft CG landings.

Also keep in mind the CG moves aft as fuel is consumed.

(Opinion alert!) With these considerations, I have a slight preference for a more forward empty CG configuration in any RV-4 with a mission involving travel. Anything you put in the plane besides the pilot moves the CG aft, so a plane optimized for acro with an aft CG really canít gross out in pax or luggage. Not that I would know, but in real safety terms I think most RVs have a much higher tolerance for exceeding gross weight than for exceeding aft CG.

Hope this bit of detail in addition to earlier posts is helpful.

Matthew
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  #10  
Old 07-08-2018, 08:59 AM
Michael Henning Michael Henning is offline
 
Join Date: Jun 2011
Location: Nashua, NH
Posts: 486
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1018 empty weight, 1750 gross, 218 is max weight for rear seat pax. Still easy to fly. No acro, faster on approach.
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RV-4 #2750
N654ML
IO-360
WW150C Prop
1018 lbs
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