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  #1  
Old 01-21-2014, 12:24 PM
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digidocs digidocs is offline
 
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Lightbulb Nuts about saving weight

A fun weight saving fact:

There are about 425 AN365-1032s in your RV-10. If you replace them all with MS21042-L3s you'll save about 1.7 lbs.

If you return the AN365s to Van's and buy the MS21042s from Spruce, it will cost about $109 or $64/lb.

David
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  #2  
Old 01-21-2014, 12:54 PM
David Paule David Paule is offline
 
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Those particular nuts are lubricated and need different torques than the nuts in the kit. It's not merely the locking torque that't affected, it's the basic torque.

Anyone have any idea what the torque shuld be?

Dave
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  #3  
Old 01-21-2014, 02:35 PM
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digidocs digidocs is offline
 
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Dave,

It looks like the spread between a -3 and and dry film lube -L3
is small and much less than the natural variation among different nuts of the
same type.





David

Citation: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA024893

Last edited by digidocs : 01-21-2014 at 02:45 PM.
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  #4  
Old 01-21-2014, 03:23 PM
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Quote:
Originally Posted by digidocs View Post
A fun weight saving fact:

There are about 425 AN365-1032s in your RV-10. If you replace them all with MS21042-L3s you'll save about 1.7 lbs.

If you return the AN365s to Van's and buy the MS21042s from Spruce, it will cost about $109 or $64/lb.
Another option to consider is AN364 nuts. Everywhere that I've needed a nut where clamping force isn't critical and bolts are loaded only in shear (adel clamps, seat belt attach bolts, etc.), I've used these. I imagine there are quite a number of other places on the airframe that could use these, but I would want to run those past Van's or a sufficiently qualified engineer.
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  #5  
Old 01-21-2014, 03:36 PM
N15JB N15JB is offline
 
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Quote:
Originally Posted by digidocs View Post
A fun weight saving fact:

There are about 425 AN365-1032s in your RV-10. If you replace them all with MS21042-L3s you'll save about 1.7 lbs.

If you return the AN365s to Van's and buy the MS21042s from Spruce, it will cost about $109 or $64/lb.

David
That is cheap compared to high end bicycles. Figure on about $1000 per pound to lower the weight on a good bike. We have a 21 lb. tandem that cost more than 4 years of college(back in the 60s)

Jim Berry
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  #6  
Old 01-21-2014, 05:44 PM
chrish chrish is offline
 
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I think most reading this could reduce the weight of the total take off weight by at least 1.7 lbs by going for a walk every day
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  #7  
Old 01-21-2014, 06:17 PM
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JonJay JonJay is offline
 
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Quote:
Originally Posted by chrish View Post
I think most reading this could reduce the weight of the total take off weight by at least 1.7 lbs by going for a walk every day
And add "do your business" as part of you preflight

I would gladly pay $64 a pound if you find another 60 of these changes to shave #100 from my 6. ( I'm not giving up my 180hp or CS etc....)

The reality is, the basic bare airframe is pretty well designed and all the little things I see posted, when added together, still make very little overall difference.
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  #8  
Old 01-21-2014, 06:51 PM
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All the little savings add up! Here are a few others that seem to be good wins:

- LiFePO4 battery (~10 lbs, $30/lb) over a PC680
- 2 blade composite CS prop (10-15 lbs, ~$100/lb)
- Cheap tires with less rubber (can be 2+ lbs per wheel, $0/lb)
- ECI tapered fin cylinders (~3lb, $???)
- Lighter and less instruments/avionics (TT22 transponder weighs 0.8 lbs, MGL V6 com or similar weighs 0.5 lbs, no vacuum pump, simple EFIS instead of steam gauges)
- Replace engine hoses with SS hardlines (one -8 builder reported 7 lbs)
- Less interior/insulation

Saving weight is so fun!

David
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  #9  
Old 01-22-2014, 07:05 AM
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HIIFLY HIIFLY is offline
 
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Default CHEEP THIN TIRES !

Ever had a FLAT at a field away from home base ? That day I wish I had solid rubber tires ! Ha . and I would have paid plenty $$$$$ to have them .
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  #10  
Old 01-22-2014, 07:19 AM
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Low Pass Low Pass is offline
 
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Quote:
Originally Posted by digidocs View Post
All the little savings add up! Here are a few others that seem to be good wins:

- LiFePO4 battery (~10 lbs, $30/lb) over a PC680
- 2 blade composite CS prop (10-15 lbs, ~$100/lb)
- Cheap tires with less rubber (can be 2+ lbs per wheel, $0/lb)
- ECI tapered fin cylinders (~3lb, $???)
- Lighter and less instruments/avionics (TT22 transponder weighs 0.8 lbs, MGL V6 com or similar weighs 0.5 lbs, no vacuum pump, simple EFIS instead of steam gauges)
- Replace engine hoses with SS hardlines (one -8 builder reported 7 lbs)
- Less interior/insulation

Saving weight is so fun!

David
I'm guilty of several of the items above. Just reduced hose weight by 15 oz (one long run) by rerouting. Saved 5 lbs (yes, 5!) going from heavy, Hooker harnesses to Crow. New starter time after 1500 hrs (good excuse anyway), saved 1.8 lbs with the new XLT Sky Tec. Oh yea, two P-mags as well... Next step, Grove gear legs.

And yes, I need to get out and walk more to reduce front seat occupant loads. But these other things are icing on the cake!

Thanks for the work on the MS21042 nuts. Excellent idea!

Last edited by Low Pass : 01-22-2014 at 12:19 PM.
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