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  #21  
Old 12-20-2019, 07:18 PM
plehrke's Avatar
plehrke plehrke is offline
 
Join Date: Sep 2006
Location: Defiance, MO
Posts: 1,828
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Of coarse the obvious. If you want to be light, best way is cut the comforts and nice-to-haves. Adds up way faster than titanium fasteners and lightening holes.

Empty Weight items (all weights below are quick guesses)
-Fixed pitch wood prop -25 lbs
-No interior except seat cushions (cloth not leather) -20 lbs
-No carpeting or sound/fire proofing -3 to 10 lbs
-No vacuum system -5 lbs
-No autopilot -5 lbs
-Electronic ignition vs mags -5 lbs
-Cheap (less ply) tires. Some of the RVs are using the high ply 200 mph ones because they get longer life. -6 lbs
-No cabin heat -2 lbs
-Day only (no position lights) -3 lbs
-Polished, not painted -30 lbs
-small and thin fairings (gear to fuse, gear to wheel pant, fuse to tail, fuse to wind screen) -5 lbs
-no redundant displays, back up instruments, and back up batteries. -5 to 10 lbs
-no Dual breaks -2 lbs
-no Dual stick -1 lb
-no electric trim and/or flaps -1 lb

Don’t forget items probably booked in useful load. All adds into weight in flight. None required though they are nice-to-have. Many of these Maybe should not be in plane all the time.
-Supplemental air
-tools
-iPads
-chocks, gust lock, tie downs, covers
-fire extinguisher
-manuals
-logbooks
-blankets, pillows, and cushions
-remote ADSB In

And a big one but very emotional and safety related.
-fly with min fuel required for expected flight. -100 lbs. (when flying local for fun don’t need full tanks)
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RV-6A - flying 970+ hours
Based at 1H0 (Creve Coeur)
Paid dues yearly since 2007

Last edited by plehrke : 12-20-2019 at 07:32 PM.
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  #22  
Old 12-25-2019, 11:27 AM
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gmcjetpilot gmcjetpilot is offline
 
Join Date: Jan 2005
Posts: 4,576
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Go on diet and exercise more, get back to your ideal weight.... Losing 10, 20,,,, ahaa 30 lbs on the plane is the same as losing weight on your frame, and it gives you health benefits.... Just a thought. (Merry Christmas, note to self step away from the Pie)

As far as air-frame weight... simple, less.... fixed wood prop, 160/180 HP, modest panel, modest interior, min paint coats.... day only,

In my early RV days I flew a few fixed pitch wood prop, 150/160, basic day vfr only RV's. They were a delight.
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George
Raleigh, NC Area
RV-4, RV-7, ATP, CFII, MEI, 737/757/767

2021 Dues Paid

Last edited by gmcjetpilot : 12-25-2019 at 11:29 AM.
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  #23  
Old 01-07-2020, 11:01 PM
Tdeman's Avatar
Tdeman Tdeman is offline
 
Join Date: May 2017
Location: Salem, OR
Posts: 61
Default Here's a Few

I've been trying to save weight wherever possible on my RV-6 build and will share a few of the things I did. Now, I have a running bet with a few guys on what my empty weight will be, so you'll notice some of these get increasingly maniacal. I'll spare you the full on weight-psycho stuff until I weigh in and either have to use it or not.

A lot of people mention the wood prop saving 25-30 lbs, but then go and put a 18lb crush plate on the nose for CG reasons With that in mind, I focused my weight savings at the tail. Ideally allowing me to run a composite prop without a weight up front.

Starting at the tail:
-Using the classic RV-6 VS and rudder (no counterbalance) (sorry 7/8/9 builders, not an option).
-Built a new set of .016 elevator skins using RV-7 counter balance arms which are longer, and position the CW horizontally, thus requiring less counterweight. (The combination of elevator counterweight and skins will be nearly a 2lb reduction alone)
-Turned a titanium tailspring on the lathe (1lb saved).
-Planning to do a billet tailwheel fork and Ti axle.
-Scallop the mating flange of the fairings and pop rivet instead of screw on.
-MS-21042 instead of AN-365's
-Round and taper those corners on your 1/8" angles and straps in the tail.

I'm hoping that by pulling 4-5lbs out of the aft-most point on the aircraft, I'm able to run a ground-adjustable composite prop without any extra weight up front (saving another 10-15lbs). Engine is a carb'd O-320.


Then of course are all the easy ones throughout the rest of the aircraft:
-Build a taildragger
-MS-21042's instead of AN-365's
-Minimal interior
-Single EFIS Glass Panel with LRU's mounted as close to power/data hub as possible.
-Careful and efficient wiring throughout (See AC-43.13B for calcs and help on minimizing wire size).
-Fuses instead of circuit breakers
-Single (or double) set of seat back hinges. Single seat back angle per side on the cross bar (speaking of which, lighten that piece of angle up!)
-Lithium battery (Easy 10lb saved compared to an Odyssey, 20lb lighter than a concord).
-Aluminum battery box (see RV-14 battery box if using an odyssey).
-Aluminum hard lines instead of rubber hose wherever feasible.
-Single set of brakes. (And throw those master cylinders in the lathe or mill to get rid of all the extruded material between the ports.)

Sometimes I ask myself if it's worth it... However, flying a heavy and lightweight RV back to back often reminds me that it is not in vain.
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  #24  
Old 01-08-2020, 07:01 AM
BCP Boys's Avatar
BCP Boys BCP Boys is offline
 
Join Date: Oct 2011
Location: Kennesaw, Ga
Posts: 881
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Quote:
Originally Posted by gmcjetpilot View Post
Go on diet and exercise more, get back to your ideal weight.... Losing 10, 20,,,, ahaa 30 lbs on the plane is the same as losing weight on your frame, and it gives you health benefits.... Just a thought. (Merry Christmas, note to self step away from the Pie)

As far as air-frame weight... simple, less.... fixed wood prop, 160/180 HP, modest panel, modest interior, min paint coats.... day only,

In my early RV days I flew a few fixed pitch wood prop, 150/160, basic day vfr only RV's. They were a delight.

Funny as heck and True. It's nice to build a light plane but so many focus on buying things that are a few pounds lighter (a battery for example) to save on overall weight and never give a thought about losing 10 pounds from the gut . I know after this past Holidays my plane gained at least 10 more pounds every time I flew
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RV-7 - Regretfully Sold
RV-10 - Sold

Supporting VAF since the first visit
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  #25  
Old 01-08-2020, 01:21 PM
redbaron redbaron is offline
 
Join Date: Aug 2013
Location: Lucerne,Ca
Posts: 272
Default Decrease wt

Fly nude save 1.5 #,s
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  #26  
Old 01-08-2020, 01:48 PM
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N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
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Having built a 998 lb -9, I'll chime in.

The +9 had a longer fuselage and wing, so you are already ahead of me.

Tip-up taildraggers are supposed to be the lightest combination, so start there.

Small engine helps, a narrow deck O-320.
Composite two bladed prop (Catto?)
P-mags (1.5 lbs lighter and no complex electrical system needed.
ECi tapered cylinders (1.5 lbs lighter than stock, IIRC.)
Smallest starter you can find.
Punch lightening holes on the seat backs.
Punch lightening holes in the bulkheads.
Use the all metal locknuts, not nylocks.
Thin washers, were you can.
Skip the electrical system altogether!
Replace all fiberglass parts with carbon fiber or aluminum, which may be lighter.
Weigh tire, wheel, and tube combinations.
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Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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  #27  
Old 01-08-2020, 04:17 PM
Dugaru's Avatar
Dugaru Dugaru is offline
 
Join Date: Jan 2016
Location: Richmond VA, USA
Posts: 595
Default Wow!

That's a crazy light -9. Climb performance must be insane!

Quote:
Originally Posted by N941WR View Post
Having built a 998 lb -9, I'll chime in.
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Based W96: New Kent International Aerodrome
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2021 Dues Paid
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  #28  
Old 01-08-2020, 05:00 PM
smokyray's Avatar
smokyray smokyray is offline
 
Join Date: Jan 2005
Location: TX32
Posts: 1,966
Default Weight a minute...

Frank,
My Early model RV4 weighed 915Lbs with no fuel or oil when the FAA DE looked at the scales during my inspection. Rather than any cool building shortcuts, I simply did without as my wallet was the LIMFAC (as we say in the military).
No paint, starter, aircraft battery, alternator, lights with a very basic interior and Fly Market avionics.
Flight characteristics with an 0-320A and Sterba Wood prop? Superb.
Cost? Under $25K (1995 dollars)
Even now you could get a RV4 in under 975 with no frills...
Yes, it can be done...
V/R
Smokey

PS: That same RV4 now with paint and avionics MT FP prop 0-320E2D weighs 955lbs, a testament to lightweight accessories and new owner diligence.

Last edited by smokyray : 01-08-2020 at 05:02 PM.
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  #29  
Old 01-08-2020, 07:21 PM
Tdeman's Avatar
Tdeman Tdeman is offline
 
Join Date: May 2017
Location: Salem, OR
Posts: 61
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Quote:
Originally Posted by N941WR View Post
Having built a 998 lb -9, I'll chime in.
Bill, was that with the O-290 up front or was that after the O-360 swap?
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Opinions expressed in this post do not necessarily represent those of my employer.
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  #30  
Old 01-09-2020, 12:52 AM
Capt Capt is offline
 
Join Date: Feb 2017
Location: Australia
Posts: 711
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My 8 is 542kg (1195lbs for you Yanks) M/T. I have all the creature comforts, I didn't want to fly around in a cold noisy T model Ford I dropped 10kg's personally, win win -

Last edited by Capt : 01-09-2020 at 12:54 AM.
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