How to build light?

[N941WR]

In a number of threads there have been some good tips on how to build a light RV and it would be cool to pull them all together.

Without getting into arguments about which is better on such things as CS props vs. FP, wood vs. metal, auto fuses vs. CB's, could we just list the things that you have done which you feel provided weight savings.

Then maybe someone might pick the best of these things and build a supper light RV.

Here is a list of things I feel helped me keep the weight down:

Tip-up taildragger
Took advantage of every weight savings called out for in the plans
Wood Prop
Small engine
Lightweight starter
Duel P-mags
No vacuum system
Electronic flight instruments
Simple electrical system
Simple VFR (one radio, transponder, intercom, handheld GPS)
Limited the interior to paint and seat cushions
Automotive flasher for the strobe power supply
LED position lights

995 lbs Empty weight (It gained 5 lbs with the autopilot installation.)

[Mel]

Originally Posted by N941WR

In a number of threads there have been some good tips on how to build a light RV and it would be cool to pull them all together.

Without getting into arguments about which is better on such things as CS props vs. FP, wood vs. metal, auto fuses vs. CB's, could we just list the things that you have done which you feel provided weight savings.

Then maybe someone might pick the best of these things and build a supper light RV.

Here is a list of things I feel helped me keep the weight down:

Tip-up taildragger Ditto
Took advantage of every weight savings called out for in the plans Ditto
Wood Prop Ditto
Small engine Ditto
Duel P-mags Slick Mags
No vacuum system Ditto
Electronic flight instruments Ditto
Simple electrical system Ditto
Simple VFR (one radio, transponder, intercom, handheld GPS) Ditto plus 2nd com
Limited the interior to paint and seat cushions Ditto
Automotive flasher for the strobe power supply Aeroflash
LED position lights

Manual trim (pitch & Roll)
Manual flaps
No autopilot
Empty Weight w/paint.....1028 lbs.
Flying beautifully for almost 16 years.

[Don Jones]

Automotive flasher for strobes???

[N941WR]

Originally Posted by Don Jones

Automotive flasher for strobes???

Use something like this SkyBright sytem:

[RV6_flyer]

Other tips:

Make all radius on bulkheads and ribs large radius. (Keep minimum edge distance from the rivet hole on the two sides that get cut off.)

Replace AN960 steel washers with AN960PD aluminum where ever possible. Use AN960-XXL and AN960PD-XXL when ever you can.

Use MS21042 all metal lock nuts instead of AN365 (MS20365).

Use the correct length bolts. Do not use bolts that are too long with washers to make them work.

Two saying from 'other' aircraft designers have about building airplanes.

"Only build it as strong as necessary but as light as possible." John Thorpe

"A simple test for everything that you put in the airplane that the regulations do not require. Take the item that is not require in you hand. Throw it up in the air. If it does not come down, it is ok to put in the airplane." Burt Rutan

These are things that I did that come to mind.

My airplane is 66 pounds heaver than Mels and I have a constant speed prop, autopilot, full Gyro panel, IFR radios, and car stereo CD. Would not do the gyro panel or full IFR radios if I were doing it again.

[rvbuilder2002]

Originally Posted by Mel

Manual trim (pitch & Roll)
Manual flaps
No autopilot
Empty Weight w/paint.....1028 lbs.
Flying beautifully for almost 16 years.

Actually Mel,
The manual elevator trim (at least the standard cable supplied by Van's) is heavier than the electric trim. The manual aileron trim is lighter.

[n5lp]

Originally Posted by rvbuilder2002

Actually Mel,
The manual elevator trim (at least the standard cable supplied by Van's) is heavier than the electric trim...

I've wondered how this all nets out? The servo and wire are lighter but then I had to add quite a bit of lead to balance the elevator that has the servo in it. Oh, and then there is the speed controller and wiring. Kind of hard to figure out.

[hevansrv7a]

Originally Posted by Mel

Manual trim (pitch & Roll)
Manual flaps
No autopilot
Empty Weight w/paint.....1028 lbs.
Flying beautifully for almost 16 years.

My -7A before paint and interior was 1051# with an IO-360. Add 20 pounds for that to Mel's 1028 and the difference is 3 lbs. Full GRT instrumentation and strobe pack but no "430". Keep in mind that the 7's wings are longer and 3 tail planes larger and electric flaps and manual pitch trim and installed wing trim. But I did nothing special - did not even drill the lightening holes in the VS spar.

However, I later added paint and interior and weighed 1129#. It's a heavy, full interior with Oregon Aero cushions. FYIO.

My thought would be, if I cared much, to skip the paint, alodine the interior as did Roberta and use lightweight cushions - maybe inflatable like the old Morgan automobiles. Helium? That's the big stuff.

My point is that all the tips in this thread are valid but I don't see that they produce much weight savings. Maybe I'm just not enough of a perfectionist. For most flights if I really want to save 75 pounds I can just leave out 12 gallons of fuel and still accomplish the mission quite well. Or just fly with a smaller passenger!

This is not aimed at Mel (who I greatly admire) but his numbers were convenient for this reply.

[Mel]

Originally Posted by rvbuilder2002

Actually Mel,
The manual elevator trim (at least the standard cable supplied by Van's) is heavier than the electric trim. The manual aileron trim is lighter.

I understand that. I was simply stating what I have. Manual trim is one of the things I chose in spite of the weight.

[allbee]

lay off the donuts helps.