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  #1  
Old 11-26-2013, 02:03 PM
ao.frog ao.frog is offline
 
Join Date: Sep 2006
Location: Manstad, Norway
Posts: 866
Default My -7 weighed in on the heavy side today, but that's OK.

Today, we performed weighing of my new -7.
As I expected, it came out on the heavy side.

Here's the base:
Basically built acc to the manual, except for dual heatmuffs and a defroster-system.
Lyc IO-360, 8,5 compression
Dual P-mags
WW 200RV prop
Single landing light
Vans RV-7 light system incl Whelen strobes
Elec trim
Manual rudder trim
Rudder pedal extensions
Full interior incl full floor math set, by Classic Aero Designs
Smoke-system by Smoking Airplanes
VFR panel, incl dual AFS EFIS: 4500 + 3400.

First ZFW with empty smoke-oil tank:
LMLG: 246.5 kg
RMLG: 247.0 kg
TW: 38.5 kg
Total 532.0 kg

Then ZFW with full smoke-tank (13,2 litres)
LMLG: 253.0 kg
RMLG: 250.0 kg
TW: 42.0 kg
Total 545 kg

Note: the plane is built with the R/H seat as pilot seat, thus the smoketank is placed behind the left seat.

Just for fun, I also noted the weights BEFORE we added all the removable parts: hatches, covers, panels, seats, interiors, wheelpants, fairings, spinner etc. (in other words all the things which are removed during annual)
LMLG: 222.5 kg
RMLG: 222.5 kg
TW: 34.5 kg
Total 479.5 kg

Quite a difference....


It came out about 21 kgs heavier than my first -7 and that makes sense: my first -7 does not have the full floor math set, nor the smoke-system.

I haven't done the math to figure out the CG yet, that's tomorrows task.
For now, just by looking at the figures, it looks like the CG will be within limits at ZFW. Then we'll see how the CG goes with different load-configurations.
__________________
Regards Alf Olav Frog / Norway
First RV-7 completed, (bought partly finished from a US-builder) 305 hrs per July 2014, SOLD
Second -7 had first flight Feb 25th 2014. 220 hrs pr July 2019. Life is good!

Last edited by ao.frog : 11-26-2013 at 02:11 PM.
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  #2  
Old 11-26-2013, 02:30 PM
MarkW's Avatar
MarkW MarkW is offline
 
Join Date: Sep 2011
Location: Edgewater, FL. X50
Posts: 1,176
Default

Can that be correct?
92.6# on the TW.
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RV9 - N14MW - Flying
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  #3  
Old 11-26-2013, 02:56 PM
Steve Barnes Steve Barnes is offline
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 593
Default Heavy T.W.

Are you weighing in level flight attitude with the level?

Steve
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  #4  
Old 11-26-2013, 03:28 PM
ao.frog ao.frog is offline
 
Join Date: Sep 2006
Location: Manstad, Norway
Posts: 866
Default

Flight attitude: level at the longeron according to the manual.

My first -7 has about 35 kgs on the TW, so I guess 38.5 kg on the TW with a lighter prop makes sense...
__________________
Regards Alf Olav Frog / Norway
First RV-7 completed, (bought partly finished from a US-builder) 305 hrs per July 2014, SOLD
Second -7 had first flight Feb 25th 2014. 220 hrs pr July 2019. Life is good!
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  #5  
Old 12-10-2013, 04:13 PM
Smilin' Jack Smilin' Jack is offline
 
Join Date: Jan 2011
Location: Cumming, Georgia
Posts: 906
Default

I had to get out the calculator but it is 1171 lbs complete. just a tad heaver than mine which came in at 1119.

If I got the conversion right approximately
246 kgs equals 542 lbs
247 kgs equals 544 lbs

38.5gs equals 85 lbs almost

Total weight is 1171 lbs.

I'd say your just a tad tail heavy... wonder why... I have the complete interior also except the front side panels but I have the arm rest. full carpet with the pads from Classic aero. Constant speed blended airfoil prop, One 10 inch Skyview and One 7 inch Skyview. ACK ELT, MGL V6 radio, Icon Com. 1 back up battery. One ADAHARS, ADS-B, IO 360 with cold air induction. 4 pipe exhaust dual heat muffs.
I am at
523 Right wheel
530 left wheel
66 tail wheel
1119 Total with a CG of 79.11

Take care using the numbers that Van's uses on their sample 1110 pound sample. A couple of their calculations are in error on the moments. Do the math yourself with an excel spreadsheet. That way you can copy and paste various examples and keep a record of the all.


Smilin' Jack
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Smilin' Jack & Anita Hunt
N507H RV7, KJZP Jasper, GA
EAA690
APRS/ WB4JKY
Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
Hunt Aviation, LLC.
Pilot Service, IPC's Biennials.
Comm Glider
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  #6  
Old 12-12-2013, 10:44 PM
jongurley jongurley is offline
 
Join Date: Dec 2011
Location: North Carolina
Posts: 94
Default

Jack this is slighty off subject, but could you post some pics of your panel with the skyviews.. were thinking about going with 10" and 7" skyview.
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  #7  
Old 12-12-2013, 11:35 PM
ao.frog ao.frog is offline
 
Join Date: Sep 2006
Location: Manstad, Norway
Posts: 866
Default Math done now

An update:

Yesterday, I finished the W & B calculations and as expected the CG was alittle further aft on this plane, compared to my first -7.

We measured the actual lenghts according to section 14 in the manual and here's the numbers:
(all calulations where done in metric/kilos and converted to inches/lbs afterwards)

Datum: 70 inches forward of wing LE
RMLG: 69,37 inches
LMLG: 68,94 inches
TW: 249,41 inches

Empty smoke-oil tank:
RMLG: 544,53 lbs
LMLG: 543,43 lbs
TW: 84,88 lbs
Total: 1172,84 lbs
Empty A/C CG: 82,20 inches aft of datum. (design range: 78,7-86,82)

Full smoke-oil tank (3,5 US GLS)
RMLG: 551,15 lbs
LMLG: 557,76 lbs
TW: 92,59 lbs
Total: 1201,50 lbs
Empty A/C CG: 83,04 inches aft of datum

I used Vans numbers for these items:
fuel: 80,00 inches aft of datum
Pilot and pax: 97,48 aft of datum
Baggage: 126,78 aft of datum

Summary: since the WW prop is lighter than the M/T prop, it makes sense that the ZFW CG is about 2 inches further aft on this -7 compared to my first -7. The smokeoil-system and the full interiour also moves the CG alittle aft.

I have made up different loading senarios now, and for X country with the wifey and me, it will be sensible to have the smoke-oil tank empty:
At the worst situation; landing with minimum fuel (20 litres), a full smoke-oil tank will allow us to have only 10 kilos of baggage.

An empty smokeoil tank allows us to have 20 kgs of baggage at min fuel.

If we land with half fuel, the allowable baggage is about 30 kgs (also empty smoke-oil)

On my first -7 (which has the heavier M/T prop) we can land at min fuel with 40 kgs of baggage.

During Phase 1 testing, I guess I'll find out how smart it was to select the WW RV-prop over the M/T prop for this plane.
If you look at the allowable baggage at min fuel/empty smoke-oil, 20 kilos of baggage is quite a bit. At least it schould be plenty as long as the wifey doesn't pack "everything" for a longweekend...

On the up-side; this plane will probably be alittle lighter on the stick during aerobatics and heavy maneuvering due to the more aft CG.
Phase 1 will be interesting.
Stand by for updates in a month or two....
__________________
Regards Alf Olav Frog / Norway
First RV-7 completed, (bought partly finished from a US-builder) 305 hrs per July 2014, SOLD
Second -7 had first flight Feb 25th 2014. 220 hrs pr July 2019. Life is good!

Last edited by ao.frog : 12-18-2013 at 11:19 PM.
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  #8  
Old 12-22-2013, 09:01 PM
Smilin' Jack Smilin' Jack is offline
 
Join Date: Jan 2011
Location: Cumming, Georgia
Posts: 906
Default

With your aft CG and heavier weight you have lost the capability of doing acrobatics with anyone else on board since you would only have about 11 gallons of fuel. And with your math you'll land out of rear CG

You plane will be less stable and more easily upset with the aft CG condition. Harder to recover from stalls and require more flying of the aircraft due to the aft CG.

There is are no pluses with an aft CG.. And spin recovery will be can be very difficult.
In this country a builder can specify any Gross weight they want provided if they check the entire flight envelope at that new gross weight. I seriously doubt if most builders test the limits of their aircraft.

During my Phase ONE I I did load my plane up and tested it up to Vne and did the all might acrobatic maneuvers and spins. I was surprised how fast the RV rotates but then again it is a far cry from C150 or Citabrias I had flown in the past. With a lot shorter wing and shorter fuselage.

Just my .02c worth
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Smilin' Jack & Anita Hunt
N507H RV7, KJZP Jasper, GA
EAA690
APRS/ WB4JKY
Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
Hunt Aviation, LLC.
Pilot Service, IPC's Biennials.
Comm Glider
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  #9  
Old 12-23-2013, 12:46 AM
ao.frog ao.frog is offline
 
Join Date: Sep 2006
Location: Manstad, Norway
Posts: 866
Default Good points

Yes, all your points are good ones.

I haven't sold my first -7 yet, so I have one sollution to the CG-problem: swap the WW prop with the heavier MT-prop.
The higher empty weight isn't ideal ofcourse, so I'll do the phase 1 testing and see how it goes, then decide what to do.
__________________
Regards Alf Olav Frog / Norway
First RV-7 completed, (bought partly finished from a US-builder) 305 hrs per July 2014, SOLD
Second -7 had first flight Feb 25th 2014. 220 hrs pr July 2019. Life is good!

Last edited by ao.frog : 12-23-2013 at 12:55 AM.
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  #10  
Old 12-23-2013, 05:40 AM
Smilin' Jack Smilin' Jack is offline
 
Join Date: Jan 2011
Location: Cumming, Georgia
Posts: 906
Default

Great post, I don't want to sound the alarm but being an instructor since 1971, I have seen my share of accidents which I believe most are avoidable. We as a small percent of people who fly around the world owe it to our families and friends that we take flying to do it in the safest maner that we can.
I have made some big mistakes in my life flying an have been blessed to make it to the next day, i showed off, buzzed houses, did rolls over the runways playing Bob Hoover in a Shrike commander and almost died. But somewhere along the line, i realized being the hot shot was going to kill me. There are a few folks that are on this site that flew with me in the 70's i was fearless which today i am not all that proud to say.
I am thankful to God that I made it to 63 and now hopefully give some understanding to younger folks flying so they have the opportunity to share the gift we have of flying with their families.
Yes i still enjoy doing acrobatics, I just do them a little higher, that is one reason I built a Van's aircraft. It is a good X/C plane and you can still have a ball doing some good acrobatic stuff.
Jack
__________________
Smilin' Jack & Anita Hunt
N507H RV7, KJZP Jasper, GA
EAA690
APRS/ WB4JKY
Retired Corporate Pilot CFI-AI, MEL
CE500, LRJT, HS25, C650, SBJT, CL60
Hunt Aviation, LLC.
Pilot Service, IPC's Biennials.
Comm Glider
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