Gross weight, likely revisited
 

As I will likely be making my first venture into the Experimental world after 40> years of flying with an RV-4 purchase, I am as usual a bit confused.:confused: So, does the definition of gross weight and it's legal implications change since the aircraft is certified in the Experimental category? Some are 'certified' with 1500 gross, others with 1600 lbs. I am aware of the fact that aircraft can be safely operated above published gross weight (Alaska FAA regs allow a 10% increase in some situations..) and that yes, once must be careful as always. Results may vary, this is not advice from me, and this remains between you, me, and the NSA. I also know ramp checks can be very rare but one must always be prepared, and that was not the reason for my question. I am just continuing on the path of knowledge to some day reach the lofty goal of being an RV-4 aviator. Thank you very much.

You bust gross, you bust a reg. That said, I've never seen a ramp fed in Wyoming. I think they're all up in Montana rubbing elbows with the glitteratti.

Welcome to the wonderful world of RV's!

A coupla points that may shed some light. First, RV's aren't "certified" at any gross weight, since they are not certified aircraft. Minor grammar point, but may help you understand a key difference.

Regarding weights, you're right. The 'seemingly' same aircraft (i.e. RV-4) can be registered with different gross weights. Think of it this way. Who determines an aircraft's gross weight? The manufacturer. Who is the manufacturer of RV-4's? The builder (i.e. not Van's). Ergo, two different individuals manufacturing two different RV-4's can have two different gross weights.

Now all that said, whether it is smart to diverge from Van's recommendations is a totally different question.

Welcome to VAF!
 

Mike, welcome to the good ship VAF:D

Who Owns the Margin?
 

you should probably read this directly from Van himself:

http://macsblog.com/wp-content/uploa...andbook_v6.pdf

A very good, factual article and well written too. Thanks for the link.

Wow. I had never read that article before. As an Aero Engineer myself, it is information to take to heart for EVERY builder. Thanks for the post.

I saw an RV4 with 1800 gross listed on its id plate, that is the highest I have seen. I can't remember the empty weight but it was pretty heavy.

agreed thats a good read.

Is the -4 really a 2- seat XC machine?
 

I read the article mentioned and I take it to heart.

With that in mind, I begin to wonder if the -4 can really be considered a 2 seat Cross Country machine'.

The Van's web page says that the Gross Weight is 1500 pounds. I'm sticking with that.

Ok so if you take me and my girl in back, we have 180+120 pounds.

32 gallons of gas is 192

say 26 for 2 chutes

50 pounds baggage

And that useful load adds up to 568 pounds.

You get a 1000 pound empty machine and your are 68 over.

And from what I can tell, I bet most -4's are a bit over 1000.

I don't want to bust gross.

I don't like taking off without a full fuel load

So do people really think of -4's as a serious 2 seat XC machine?

And then there's single seat acro with me, full tanks and a chute and I'm 5 pounds over the acro limit of 1375.


I suppose I could fly acro with less than full tanks. But that brings up a totally unrelated question:

Does everyone fill the tanks after a day's flying to avoid condensation? If so then every flight is a full-tanker. Burning off 5 pounds for start/taxi/run-up isn't too hard, I suppose.

Gregg,

I did the same math; I'm 175 and my wife is 125. We plan to take the machine to Michigan 2x yearly and TX or CO once yearly.

Personally, I omitted the chutes and plan for ~25lb baggage. I don't know of a good justification for flying with chutes X/C and we've spent enough time traveling by motorcycle (2-up on a sportbike) that she knows how to pack light.

IMO, launching with less than full tanks is no big deal, in most cases I prefer to.

A -8 is a more humane traveling machine, and makes 2-up acro possible, but without partners is out of the budget range for me.