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  #21  
Old 08-03-2018, 03:47 AM
autoglide autoglide is offline
 
Join Date: Aug 2009
Location: Rockport,TX
Posts: 358
Default -4 Question

I fly a -4 with a Sensi FP prop (43# w spacer). Empty wt is 1000#.
Am thinking about selling the Sensi, and installing a wood Prince, Pacesetter, or Catto. Will lose about 23-25# on the nose. I weigh 135#. Wife weighs 125#.
With half to full fuel, will I notice much difference solo vs 2 up?
With the Sensi, don’t notice much diff......
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  #22  
Old 08-03-2018, 03:42 PM
Dayton Murdock's Avatar
Dayton Murdock Dayton Murdock is online now
 
Join Date: Jan 2005
Location: Carson City NV
Posts: 528
Default

This is the CG/ Weight and Balance for my RV-4


WEIGHT & BALANCE DATA

Make: Van’s Aircraft
Model: RV4 Serial # 4354 Registration # N359DM

Datum= 60 inches forward of wing leading edge. (L.E.)
Design C.G. Range = 15% to 29% of wing chord, or 8.7” to 16.8 inches from L.E., or 68.7 to 77.4 inches aft of Datum.
Wing L.E. = 60”aft of datum.
Main wheel, right = 60”aft of datum.
Main wheel, left = 60.3”aft of datum.
Tail Wheel = 237.5”aft of datum.

Aircraft weighed empty in level flight attitude.

Weight (lbs) Arm (ins) Moment (lbs. in)
Right Wheel 484 60 29040
Left Wheel 499 60.3 30089.7
Tail Wheel 50 237.5 11875
Total: 1036 70997.08

CG=70997.08/1036 / = Empty moment of aircraft 68.53” aft of datum



Weight and Balance Work Sheet

Datum= 60 inches forward of wing leading edge. (L.E.)
Design C.G. Range = 15% to 29% of wing chord, or 8.7” to 17.4 inches from L.E., or 68.7 to 77.4 inches aft of Datum.
Wing L.E. = 60” aft of datum.
Oil = 40” aft of datum.
Fuel = 70” aft of datum.
Pilot = 82.5” aft of datum.
Passenger = 107” aft of datum.
Baggage = 130” aft of datum.

Gross Weight CG

Weight Arm Moment
Aircraft 1036 68.53 70997
Fuel 192 70 13440
Oil (8 qts.) 15 40 600
Pilot 180 82.5 14850
Passenger 160 107 17120
Baggage 5 130 650
Total 1588 11765.7
CG 11765.7/1588 74.09”

Most Aft C.G. (Gross Weight Min)

Weight Arm Moment
Aircraft 1036 70997
Fuel 30 70 2100
Oil (8 qts.) 15 40 600
Pilot 180 82.5 14850
Passenger 160 107 17120
Baggage 5 130 650
Total 1426 106317
CG 106317/1426 74.56” aft


Most Forward C.G. (Two Occupants.)

Weight Arm Moment
Aircraft 1036 70997
Fuel 192 70 13440
Oil (8 qts.) 15 40 600
Pilot 180 82.5 14850
Passenger 120 107 12840
Baggage 0 130 0
Total 1543 112727
CG 112727/1543 73.06 aft

Most Forward C.G. (Std. Pilot Wt.)

Weight Arm Moment
Aircraft 1036 70997
Fuel 30 70 2100
Oil (8 qts.) 15 40 600
Pilot 170 82.5 14025
Passenger 0 107 0
Baggage 0 130 0
Total 1251 87722
CG 87722/1251 70.12” aft


RV4 Weight and Limits – easy Reference
Recommended Gross Weight 1650 lbs
Aerobatic Gross Weight 1375 lbs
Forward CG Limit 15% of cord or 8.7” aft of leading edge
Aft CG limit 30% of cord or 17.4” aft of leading edge
Aerobatic Aft CG limit 27.5% of cord or 15.9” aft of leading edge
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Dayton Murdock
VAF#408 RV4 N359DM Flying 985 hrs. 8/15/18
Builder Log
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  #23  
Old 08-03-2018, 08:12 PM
smokyray's Avatar
smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,731
Default Four-ward CG...

Quote:
Originally Posted by berniematic View Post
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.
Bernie,
Good considerations. I finished my RV4 25 years ago after reading a magazine ad from Vans touting "Total Performance." The plans back then were pretty specific concerning aft CG and Aft of Datum loads. Building an RV4 gives you a distinct advantage as to the CG loading but it varies greatly depending (as mentioned above) on weight out front.
If nothing else, find a builders manual and read it through. You'll be glad you did.

My RV4 weighs 945lbs with an 0-320WD firewall mounted Odyssey battery, lightweight starter/alt and Catto prop out front. I set my max weight aft of the roll bar of 200 lbs. This was attained after several flights with a heavy passenger or some large parts I carried with the back seat removed. This included an air compressor, a disassembled 0-320, Honda Trail 70, etc...
I've flown just about every RV4 iteration over the years. The 0-360/Hartzell combo airplanes are a bit nose heavy solo but fly sweet with a 100lb pax. The 0-320/composite or wood, fly incredible solo or with a lighter weight pax. (pretty girls, grand kids etc)
I personally use fuel to manage CG as the tanks are forward of the datum which is right under your butt. Heavy load? Add fuel, empty back seat, fly lighter.

Like the F16, the RV4 for me is the most fun CG-wise approaching relaxed static stability, or the aft datum.

V/R
Smokey

PS:Personally after 3000 hours, 25 years and alot of "yanking and banking", the 0-320/fixed pitch composite or wood is the preferred mode, but again, my mission may be different than yours.
I like simplicity, light weight and enjoy the occasional 1V1...

Last edited by smokyray : 08-03-2018 at 08:24 PM.
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  #24  
Old 08-03-2018, 11:20 PM
mr.sun mr.sun is offline
 
Join Date: Aug 2006
Location: Wet, Western Washington
Posts: 99
Default Weight in back ?

I have been trying to shift weight forward in my RV7. Vans tool box kit was a fun project for my son and I and it fits well on the floor between our feet. I made some hold down brackets and painted it so it blends in with the floor. Now, all the tools I used to keep in back are up in front. Shifted CG forward with no change in flying weight.
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Greg RV-7 flyer
Donated Again
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  #25  
Old 08-03-2018, 11:21 PM
mr.sun mr.sun is offline
 
Join Date: Aug 2006
Location: Wet, Western Washington
Posts: 99
Default Weight in back ?

Now to figure out a mount for my O2 tank up front.....
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Greg RV-7 flyer
Donated Again
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