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Weight and Balance numbers??? RV-7

F

float208

Well Known Member
Would any of you RV-7 Drivers be willing to share what your aircraft weight is and who much of that is on the tailwheel, and last what kind of prop do you have... I am working on the weight and Balance and am finding the plane to be extreamly tail heavy 93# to be exact... This puts me way out on the CG.... in all but solo light on gas situations....

Thanks
 
-7 Tail Weight

I ended up at 1128, 69.25 on the tail with the Hartzel BA c/s prop/ and an AeroSport XP-360 injected.

What did you get for your mains?
 
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RV-7 W&B info

Here's my data...

Rt Main 483# @ 68.5"
Lt Main 501# @ 68.5"
TW 70# @ 248"

Empty Wt 1054
CG = 80.45

This is with an IO 360 with Hartzell C/S prop.
 
Weight

My Empty is 1130#. 93# on the tail, and about 518# on each main. I have a Whirlwind Prop which is light, but the Battery is on the firewall and eveything else is in normal locations, nothing but 1 small strobe powerpack in the tail. I cannot figure out why the tail is so heavy. My -8 was only 55# on the tail This is strange... If I add the wieght of a Hartzell on the front the tail still weighs 87# so a prop swap isn't going to do the trick either.
 
Painted RV-7 w/ pants and fairings, IO-360, WW200RV prop w/2.25 spacer, James long cowl, plenum, seats and front carpet, light duty panel. ELT and Strobe pak behind Pax seat. oversize main tires(+5#)

PA130534.jpg


Certified aviation scales.

right main 511# at 68.5"
left main 514# at 68.6"
tail wheel 70#

Total 1095# @ 80.2"c.g.
 
RV7, O-360 ND with Hollow Crank, Dual Mags and Carb. Metal FP Sensenich Prop, battery on firewall, Minimal Flightline Interior, Dual Dynon EFIS/EMS, VFR only radio/GPS gear. Bell TW Fork, rest all Van's. No paint...

484 lbs right main
476.5 lbs left main
71 lbs TW

1031.5 total

80.89" empty CG (full of oil)



RV7's tend to be tail heavy (well not tail heavy but not on the fwd limit) empty. Wait till you see what this is going to do to your baggage limit! (Remember to run the numbers at minimal fuel)
 
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Float208, are you leveling the plane prior to weighing it? The longerons at the cockpit must be level (fore - aft and side - side) prior to weighing anything.

If you're weighing the TW with the tail still on the ground, you're going to get a heavy weight! See Hydroguy's photo to see how the plane should look when you're weighing it. (You probably already know all of this, but someone else reading this thread may not know it yet...)
 
weight..

Weighed it level, just like in the photo. Just pulled the tail fairing off looking for hidden weights... nothing....
 
Tare

You're not inadvertently weighing the blocks holding the tail up, by any chance? Zero the scale after adding the blocks.

Just thinkin' out loud..................:eek: Not that I would ever do anything like that. Or mismeasure by exactly 10".............:(
 
tail heavy

OK, So I set it up and weighed it again... perfect 0.0 level, the tailwheel is the only thing on the aft scale on top of a benchT tried different scale (bathroom target scale) and also read 92# on it... I even weighed myself on each scale to see the same correct number show up each time... The only thing I can think of is for some reason something is different placing the wheels farther forward than normal or something that would change the measuring points. If the main wheels were just a couple inches aft it would have a big difference in the weight distribution... Is there any way I have gear legs or an engine mount that would change this... I guess in the morning I am going to have to start dropping plumb lines and find the actual datum and where the wheels fall into all this mess. 20# is a huge difference. My RV-8 was 56# on the tail. For me to offset this I would have to add #45 or so to the spinner.... Anyhow thoughts again???
 
Where is Dan C's website?

I'm having problems with my RV6 CG and someone mentioned Dan C's web-site for examples. Can anyone tell me who he is and where his website is?

Thanks
 
**** heavy tail

OK, so I can't leave things alone... Went out and we leveled the plane again, droped lines measured Datums, and the wheels are right where they should be for doing the weight and balance. Everything seems to be where it should be... I am flustered because I have finished 3 RV's and never have I seen a tail this heavy...
 
I have a W & B spreadsheet already set up for the RV-7 (includes arm distances based on Van's specs). It gives a picture/graph to show if your weight/balance is ok for Normal/Utility/Aerobatic category of flight at take-off and landing weight. You should be able to plug in weights for each wheel and get correct results - as long as your wheels are all where they belong!

Send me your email if you want the file.

WeightandBalancescreenshot.png
 
I had a similar problem with my RV7 originally. Mine has an O-360 and at the time I had a Sensenich prop. My tail wheel weighd 85 lbs! Like you I did not like that and had very little lugage capacity. The Sensenich prop probably weighs more than your Cato (float208). These airplanes are designed for a Hartzel weight up front. I then added a 22lb prop spacer instead of the AL one. This did two nice things. My tail wheel went to 79 lbs and the engine ran real smooth. Still I had to be careful with baggage weight. Eventually I installed a Hartzel and have the same tail wheel weight that Scott reported, 70 lbs. Hope this helps.
 
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RV-7 needs weight up front

RV7AV8R said:
I had a similar problem with my RV7 originally. Mine has an O-360 and at the time I had a Sensenich prop. My tail wheel weighd 85 lbs! Like you I did not like that and had very little lugage capacity. The Sensenich prop probably weighs more that your Cato. These airplanes are designed for a Hartzel weight up front. I then added a 22lb prop spacer instead of the AL one. This did two nice things. My tail wheel went to 79 lbs and the engine ran real smooth. Still I had to be careful with baggage weight. Eventually I installed a Hartzel and have the same tail wheel weight that Scott reported, 70 lbs. Hope this helps.
Click to expand...

The weight-and-balance data that Dan Checkoway collected and posted on his website showed that the RV-7 tends toward tail heavy unless it has a Hartzell prop, an IO-360, and no accessories installed aft of the baggage bulkhead. In order to use the 100 pound baggage capacity, you should try for an empty weight CG of 80 inches or less.
 
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one more for reference

Here are my numbers -- one more for comparison. I would consider mine on the heavier side. A/p servo & Strobe power pac is behind the baggage bulkhead. Two batteries just inside of the firewall. Full up classic aero interior.
Total empty - 1131#
L Main W - 538#
R Main W - 521#
TW - 72#

Empty CG - 80.0
 
DakotaHawk said:
I have a W & B spreadsheet already set up for the RV-7 (includes arm distances based on Van's specs). It gives a picture/graph to show if your weight/balance is ok for Normal/Utility/Aerobatic category of flight at take-off and landing weight. You should be able to plug in weights for each wheel and get correct results - as long as your wheels are all where they belong!

Send me your email if you want the file.

WeightandBalancescreenshot.png
Click to expand...

I would love a copy of that spreadsheet! I will send a PM with email.
 
'Nuther data point for you...

Right main 480#'s
Left main 492#'s
Tail 73.5#'s

Rounded up weight 1046 empty, cg 81.59"

Full Flightline interior, O-360, three blade Catto prop with AL 4" spacer AND the 2" longer O-320 engine mount.
 
another data point

Same issue with -7 and sensenich FP prop, could not carry full baggage at min fuel as would be aft of CG. Added landoll which moved everything back in range.
Just switched to Catto 3 blade which with the Sabre spacer weighs 24 lbs versus the sensi with spacer that weighed 42 lbs, added sabre 14 lb crush plate and kept the landoll which looks like it will bring it all back to spec (had some margin with the landoll)
Full interior with tonneau cover and elt and strobe power pack aft of baggage compartment.
 
The graphical W&B spreadsheets shown above are on my website as I created them based upon others I had seen on the web with slight improvements and by requests by others to create spreadsheets for other models.

I was just made aware of a typo on all of them today. I've fixed the typo and hope they are now error-free. RV-4 through RV-10 are represented including A models. No RV-12 yet.

Please feel free to download and use at your discretion. Just make sure you verify all the numbers you get. All are located here:

http://www.rv7-a.com/n447rv_documents.htm
 
What did you do for a cowl...

cjensen said:
'Nuther data point for you...

Right main 480#'s
Left main 492#'s
Tail 73.5#'s

Rounded up weight 1046 empty, cg 81.59"

Full Flightline interior, O-360, three blade Catto prop with AL 4" spacer AND the 2" longer O-320 engine mount.
Click to expand...

... Chad, and how much work was it fitting the cowl to the wider 360 engine?

We exchanged e-mails a long time ago, so I was aware of your (good) decision to use the 360 on the 320 mount. Nice, light plane - good for you.

LarryT
 
uk_figs said:
Same issue with -7 and sensenich FP prop, could not carry full baggage at min fuel as would be aft of CG. Added landoll which moved everything back in range.
Just switched to Catto 3 blade which with the Sabre spacer weighs 24 lbs versus the sensi with spacer that weighed 42 lbs, added sabre 14 lb crush plate and kept the landoll which looks like it will bring it all back to spec (had some margin with the landoll)
Full interior with tonneau cover and elt and strobe power pack aft of baggage compartment.
Click to expand...

I have to ask, What is landoll?
 
Landoll

It is a harmonic balancer ring made by Mark Landoll, weighs about 12 lbs and bolts to the flywheel/starter ring. Smooths out the engine pulses and seems to work well in my 7 at cruise settings. Does not require any cowl mods.
 
LarryT said:
... Chad, and how much work was it fitting the cowl to the wider 360 engine?

We exchanged e-mails a long time ago, so I was aware of your (good) decision to use the 360 on the 320 mount. Nice, light plane - good for you.

LarryT
Click to expand...

Hey Larry,

I didn't have any issues with width on the cowl, SJ by the way, but I did have Will make an extension to the aft end of my cowl to allow for the longer mount, and that's why I didn't have any issues with the width.
 
Thanks Chad

I wasn't planning to use an SJ cowl, but maybe that would simplify things. I think I would like to go with a low compression 375 on a 320 mount w/ Catto prop and lightweight engine accessories. Trying to make up for my personal 240 Lbs. of ballast aft of the empty CG and still be able to have lots of baggage capacity.

Larry
 
Larry,

While the SJ is tight, it will fit around the O-360. However, if you are going to use SkyBolt fastners, make sure to space them so they don't hit the front two cylinders.
 
1115 pounds

with a Lycoming IO-390 and 72" Hartzell

P9095826.jpg


Left main: 525 lbs.
Right main: 535 lbs.
Tail wheel: 55 lbs.

Bill
RV-7 N151WP
Lees Summit, MO
 
walter said:
The graphical W&B spreadsheets shown above are on my website as I created them based upon others I had seen on the web with slight improvements and by requests by others to create spreadsheets for other models.

I was just made aware of a typo on all of them today. I've fixed the typo and hope they are now error-free. RV-4 through RV-10 are represented including A models. No RV-12 yet.

Please feel free to download and use at your discretion. Just make sure you verify all the numbers you get. All are located here:

http://www.rv7-a.com/n447rv_documents.htm
Click to expand...

Walter, I would allow the user to enter the arm as well as each individual aeroplane is slightly different from the factory quoted measurments.

Just a suggestion.

Here is my RV-3B weight and balance calculator. Please use it if you want to complete your library of calculators for Vans Aircraft.

RV-3B Weight and Balance
 
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There are two tabs on the spreadsheet (bottom left corner). The Data tab allows the user to customize the spreadsheets to their airplane(s). If you are unfamiliar with Excel just shoot me an email or pm and I'll see what I can do to help.
 
billgill said:
with a Lycoming IO-390 and 72" Hartzell

P9095826.jpg


Left main: 525 lbs.
Right main: 535 lbs.
Tail wheel: 55 lbs.

Bill
RV-7 N151WP
Lees Summit, MO
Click to expand...

Bill, Is the 0-390 heavier than an O-360? That light tail weight makes me jealous. Maybe the RV7 is made for the O-390 and Harzell.
 
if you're still looking for more data.....

Below is copied from my weight and balance spreadsheet. The plane is painted, has a Sensenich and aerosport 0-360, firewall battery, 2 dynons, autopilot, no prop weights, and includes a few pounds of tools, control locks, and flashlights. We weighed it totally full and had to calculate the empty wt. and empty wheel weights after subtracting an average full usable fuel wt.

Tailwheel came out to 70.3 pounds. With my tiny wife as passenger, we can only take 89 pounds of baggage on a normal cross country trip, so I'm considering that harmonic balancer. Seems odd to add weight in order to carry more, but.... Also, the way I see it, when you're light on fuel, you're closer to the worst case for rearward CG on the -7.




Weight and Balance RV7, full tanks, canopy closed,
all tools, flashlights, charts, headsets, GPS onboard
weight arm moment % of wt. calc. Mom. calc..Wt.
Tailwheel 86.1 249.25 21460.43 0.200529486 17514 70.27
Left Main 615 69.25 42588.75 0.397955780 34756.98 501.91
Right Main 620.5 69.25 42969.63 0.401514734 35067.82 506.39
Full fuel CG 1321.6 80.98 107018.8
fuel wt. -246 80 -19680
EmptyCG 1075.6 81.2 87338.8
sample CG:

fuel lbs 240 80 19200
pilot 175 97.48 17059
pass 100 97.48 9748
baggage 89 126.78 11283.42

takeoff weight, CG 1679.6 86.11 144629.22
fuel used -175 80 -14000
landing weight,CG 1504.6 86.82 130629.22
Forward CG limit 78.7
Rear CG 86.82 Utility Category
Rear CG 84.5 Aerobatic, 1600lbs.
 
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