WingedFrog

WingedFrog

Well Known Member
... that is empty weight is 747 pounds!
Empty arm is 81.58 inches
Interested in hearing some figures from other builders.
Plane fuselage is painted and I have the flightline interior except for the top bulkhead panel (see recent thread about that). Wings are not painted. I did not prime the inside of the plane, just alodined the inside of the wings.
DAR visit scheduled tomorrow...
 
To be more meaningful, we need to know: wheel pants? Autopilot? Avionics?
Looks like a pretty respectable weight to me!
Good luck on the AW certificate tomorrow!
 
DonFromTX said:
To be more meaningful, we need to know: wheel pants? Autopilot? Avionics?
Looks like a pretty respectable weight to me!
Good luck on the AW certificate tomorrow!
Click to expand...

Good point, Don: no wheel pants, autopilot, light kit, ELS, Skyview.
 
742 lbs - painted, no wheel pants, no interior, Skyview with Autopilot.

In my case: MY 737 IS AN RV-12.


Bob Bogash
N737G
 
Follow-up on Airworthiness

N124BX passed Airworthiness Certification on 08/23/2013.
The main problem I had was to open the cover under the seats so that the DAR could have a look at the controls... about 50 nutplate screws. Overall it was a good thing to do as he found an electric wire rubbing against the control rod and a couple of cotter-pins that were not fully bent.
The hilarious part was when the DAR started moving the sticks which produced an horrible "cling" I had never heard before :eek:. We soon located the noise to be an interference of the flapperon skin (both flapperons) with a rivet head on the fuselage! What happened is that the temperature was in the mid 90s for the first time since I installed the wings and the flapperons grew a tad longer, enough to hit the rivets... I mentioned the precision of my workmanship as both flapperons were affected the same way. You guys in the north better watch your flapperons when you come south!
 
I was alarmed when you said the "panels UNDER the seats". I suspect you meant the center tunnel covers?
 
Are you guys using aircraft scales or bathroom scales? I used three bathroom scales and rotated them for three readings. Then I averaged the readings at each spot. I came up with 736 lbs using wheel pants, interior, dual D180, AP 74 and paint.

I did one over gross test flight at 1350 and still got 400 FPM at 2500 Ft DA on takeoff.
 
RFSchaller said:
Are you guys using aircraft scales or bathroom scales? I used three bathroom scales and rotated them for three readings. Then I averaged the readings at each spot. I came up with 736 lbs using wheel pants, interior, dual D180, AP 74 and paint.

I did one over gross test flight at 1350 and still got 400 FPM at 2500 Ft DA on takeoff.
Click to expand...

Rotating the scales will only average the amount of error difference between the scales. It will not resolve the errors if they are all off in reading slightly. The only way to confirm accuracy would be to weigh a known reference weight on each scale (such as a 30 gal barrel of water)

I have been involved with weighing enough different RV-12's that I feel pretty confident in saying that your weight is probably low by at least 10 pounds.
It is very easy to build an RV-12 heavier than a typically equipped one would be, but it is pretty hard to build it lighter.
 
Scott,

I did adjust them all to read a 200# known weight. Remember even a 10 pound error is only 1.5%. Sometimes I think we are kidding ourselves when we think in terms of a few percent. Or as we used to say in subs: don't sweat the small stuff!



Rich
 
As we used to say (and still say) in Part 121 Air Carrier ops, we operate with "Standard Weights" for passengers, etc. The days of having people and their bags step on the scales at check-in have long since faded into history.

The result for big airplanes can easily be 15,000 lbs or more - difference between calculated weight and actual weight. An even bigger percentage variation than 1.5%. In addition, in service, between weighings, these airplanes can actually acquire thousands of pounds of lint, dust, and assorted detritus (those grungy carpets and seat-back pockets.)

I've noticed my RV-12, in just a short period of time, seems to be "acquiring" detritus in some similar mysterious fashion. Must be an "airplane thing".......

Bob Bogash
N737G
 
I don't mean to suggest anyone should ignore W&B, and I would never fly with CG out of limits, but I don't worry about the effect of a 10 to twenty pound error in gross weight. I've used bathroom scales on 4 homebuilts and never had an issue.
 
RFSchaller said:
Are you guys using aircraft scales or bathroom scales? I used three bathroom scales and rotated them for three readings. Then I averaged the readings at each spot. I came up with 736 lbs using wheel pants, interior, dual D180, AP 74 and paint.

I did one over gross test flight at 1350 and still got 400 FPM at 2500 Ft DA on takeoff.
Click to expand...

RFSchaller said:
I don't mean to suggest anyone should ignore W&B, and I would never fly with CG out of limits, but I don't worry about the effect of a 10 to twenty pound error in gross weight. I've used bathroom scales on 4 homebuilts and never had an issue.
Click to expand...

I can fully understand your point about it only be 1.5 %, but then I can't understand why you would bother to mention rotating and averaging the scale values. If you are willing to accept the 1.5 %, why would the small error difference between the scales matter?

Just to clarify... I wasn't meaning to imply there was an issue with your airplane because of the weight you quoted, just pointing out (since many of the posts in this thread are people mentioning the weight of their RV-12) that in my opinion your quoted weight is probably at least 10 pounds low, so that other people reading the thread have info regarding what an RV-12 equipped the same as yours would likely weigh.
 
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Scott,

I rotated the scales because I don't know the accuracy ( no published number) but I figured the error would be random among the scales and average out. The third scale let's you know if one of the other two is really an outlier.

The nice thing about a design and kit like the RV-12 is that it produces consistent results so if you follow the plans you can't really screw up too bad! :)

Rich
 
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