Van's Air Force
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Fuel load with pax
- Thread starter FlyFastJP
- Start date
Offloading fuel?
Hi
I would never do this. In the UK max gross is 1550lb. That means I can have full fuel, me 160 lbs, a passenger of max 196 lbs.
You will find the 4 becomes much more sensitive in pitch as the c of g moves rear. Fuel load is pretty much on the c of g, so in my case trading fuel for a heavier passenger would just make the aeroplane much more twitchy in pitch, that is not good especially when landing, so for me is a big no, no.
There are a number of W and B calculators available for the 4 online, use of these will keep you safe. Bear in mind the 4 is really a 1 plus 1 sports car, not a load lugger. It will carry two adults but is then not aerobatic unless the PX is very light.
Again in my 4 if I take my wife in the rear seat 115lbs, after we have burned off fuel to 10 gallons a side we just come into the aerobatic envelope.
So, the simple answer is if you are determined to take heavy loads dont fill it up to the top!
Hi
I would never do this. In the UK max gross is 1550lb. That means I can have full fuel, me 160 lbs, a passenger of max 196 lbs.
You will find the 4 becomes much more sensitive in pitch as the c of g moves rear. Fuel load is pretty much on the c of g, so in my case trading fuel for a heavier passenger would just make the aeroplane much more twitchy in pitch, that is not good especially when landing, so for me is a big no, no.
There are a number of W and B calculators available for the 4 online, use of these will keep you safe. Bear in mind the 4 is really a 1 plus 1 sports car, not a load lugger. It will carry two adults but is then not aerobatic unless the PX is very light.
Again in my 4 if I take my wife in the rear seat 115lbs, after we have burned off fuel to 10 gallons a side we just come into the aerobatic envelope.
So, the simple answer is if you are determined to take heavy loads dont fill it up to the top!
fixnflyguy
Well Known Member
full fuel for me.
I always load full fuel with pax. Better CG, plane Flys fine. I have a 200 lb. max for back seater and I'm 205. As other comment, pitch control is very light, and you need to be tender when flaring out. Acro is not recomended 2 up, and as fuel level goes down, CG will move aft. I am almost always flying with a pax...making RV grins happen!
I always load full fuel with pax. Better CG, plane Flys fine. I have a 200 lb. max for back seater and I'm 205. As other comment, pitch control is very light, and you need to be tender when flaring out. Acro is not recomended 2 up, and as fuel level goes down, CG will move aft. I am almost always flying with a pax...making RV grins happen!
rv7charlie
Well Known Member
My bare bones -4 (320, wood prop) weighs 910. Have you considered offloading some airframe mass, instead of fuel? And is any of your mass offloadable? (Some can't afford to lose any weight; others can lose 20-30 lbs & never miss it.)
And (not to start a big debate here) if you're willing to remain in 'normal' category instead of utility or acro, there is the option of going back to phase one & testing at a bit higher gross weight, to gain some flexibility in loading. Note that I'm *not* saying to go out and pull g's at higher than recommended weight. And there are other hazards, like landing loads, spin resistance, etc. But raising gross weight limits has been done successfully by others. Just educate yourself on the limits and hazards.
Charlie
And (not to start a big debate here) if you're willing to remain in 'normal' category instead of utility or acro, there is the option of going back to phase one & testing at a bit higher gross weight, to gain some flexibility in loading. Note that I'm *not* saying to go out and pull g's at higher than recommended weight. And there are other hazards, like landing loads, spin resistance, etc. But raising gross weight limits has been done successfully by others. Just educate yourself on the limits and hazards.
Charlie
Mark Albery
Well Known Member
CG is a lot more important than gross, as suggested. A phase 1 increase to 1550 or 1600 (the RV-6 is 1600 and structurally similar), would increase utility quite a lot.
I believe Jon Johansson was about 2000lbs over gross on his planned flight from New Zealand to South America!
I believe Jon Johansson was about 2000lbs over gross on his planned flight from New Zealand to South America!
777Dave
Well Known Member
Good advice
Some very important points raised here. C of G more important than max weight. My airplane is 990# empty. I am 180#. Max takeoff weight 1650#.
To stay in the envelope I limit pax weight to 200# and no baggage. Also full fuel.
A friend mentioned that returning from OSH years ago with his teenage son and wet camping gear, on approach with 1/4 fuel, he had trouble controlling the airplane (pitch).
Cheers.
Some very important points raised here. C of G more important than max weight. My airplane is 990# empty. I am 180#. Max takeoff weight 1650#.
To stay in the envelope I limit pax weight to 200# and no baggage. Also full fuel.
A friend mentioned that returning from OSH years ago with his teenage son and wet camping gear, on approach with 1/4 fuel, he had trouble controlling the airplane (pitch).
Cheers.
FlyFastJP
Well Known Member
I didn't build the plane, so I'm not sure on regs about redoing test flights. Mine has an O-360 and wood prop. Bare bones otherwise. CG is of course a concern...but I was just thinking about gross right now. Did some calculations and came up with only being able to take a 12 year old when tanks are full.
rv7charlie
Well Known Member
Anyone can do anything to a homebuilt experimental (repairs, maintenance, mods, etc), *except* the annual condition inspection, which must be done either by the builder holding the 'repairman's certificate', or the holder of at least an A&P ticket.
So you can do pretty much anything you want, then submit a letter (usually a fax) to your FSDO stating that you need to return the plane to phase one for testing and requesting a test area. After flying the tests, you make a log book entry detailing results of the tests and new limits, if any. The exact procedures/requirements vary slightly depending on when the oplims were issued (various versions have been used over the years), but that's basically all there is to it.
Having said that, if you really aren't familiar with the plane, its construction, etc, getting help from someone with experience would be smart, for safety and to help the process go more smoothly. There should be someone in a local EAA chapter that would be willing to help you.
So you can do pretty much anything you want, then submit a letter (usually a fax) to your FSDO stating that you need to return the plane to phase one for testing and requesting a test area. After flying the tests, you make a log book entry detailing results of the tests and new limits, if any. The exact procedures/requirements vary slightly depending on when the oplims were issued (various versions have been used over the years), but that's basically all there is to it.
Having said that, if you really aren't familiar with the plane, its construction, etc, getting help from someone with experience would be smart, for safety and to help the process go more smoothly. There should be someone in a local EAA chapter that would be willing to help you.
Infidel
Well Known Member
It doesn't hurt to do a new weight & balance on your plane. Planes will and do get heavier over time. As already mentioned, CG's IMO are more important than gross. Granted you fly utility and casually.,
I've hauled a 205 lb passenger in the back seat, still within parameters, and with full fuel its not so bad. But I do limit my cross country's with him to half tanks, which requires more stops for fuel. Yes, we are heavier with full tanks but, pitch is easier with half tanks plus.
I've hauled a 205 lb passenger in the back seat, still within parameters, and with full fuel its not so bad. But I do limit my cross country's with him to half tanks, which requires more stops for fuel. Yes, we are heavier with full tanks but, pitch is easier with half tanks plus.
Hmmmm, what does a 12 year old child weigh. In my experience the come in different sizes and weights??
keijidosha
Member
I agree. I’m also a new second owner of an RV4. I have also heard that rear CG is touchy to fly, and original calcs have kept my back seat empty. After mods and paint, I’m now at 994# empty weight (O320, Sensenich FP prop, long gear). I re-did the Weight and Balance and mine is kind of nose heavy (67.59”). Be sure to check your main wheel Arm distance as I have long gear and it is ~1” behind the leading edge, not in front. With new calcs, it is almost impossible for me to hit aft CG limit. Just did a test flight today with 140# in the rear passenger seat at 1500# gross and no problem.
