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humptybump

Well Known Member
I'm. Of sure why he other thread was closed. It may happen here too. Anyway, two tips for how to build light ...

Battery - there are some new technologies for lighter batteries.

Wood prop - it was suggested if a Catto might be lighter than a wood prop. I can say that Craig just finished a "bolt on replacement" for my Aymur Demuth. The wood prop is a few pounds lighter that Craig's composite (not that I'm complaining).

Other tangible ways to stay light?
 
No wheel pants or fairings. Lighter tires (fewer plies). One Comm radio, remote very lightweight transponder (the Trig weighs almost nothing). Fuses only - no breakers or VP system. SD-8 alternator? That would save a few pounds for sure!

How about leaving the wingtips off and just closing them with flat aluminum plates? Fibergalss isn't all that light. Oh - isn't the taildragger lighter than the tricycle? You could put a lightweight DJM tailwheel on it and save another 14 ounces....
 
I'd still like to see the path to an 888 lb empty weight for a -6.

Single Skyview (or GRT, etc) with both flight and EMS info.
Remote transponder and com, controlled via Skyview.
Lightweight interior.
Wood prop.
No paint.
Tailwheel.
Slider vs. tip-up - Any weight savings there?
Lightweight starter.
Lightweight Li-ion battery.
No carpeting or interior panels.
Lightweight foam/fabric seat cushions.

That's all I can think of!
 
Snowflake said:
I'd still like to see the path to an 888 lb empty weight for a -6.

Single Skyview (or GRT, etc) with both flight and EMS info.
Remote transponder and com, controlled via Skyview.
Lightweight interior.
Wood prop.
No paint.
Tailwheel.
Slider vs. tip-up - Any weight savings there?
Lightweight starter.
Lightweight Li-ion battery.
No carpeting or interior panels.
Lightweight foam/fabric seat cushions.

That's all I can think of!
Click to expand...

I've looked at mine time and time again with the idea of cutting weight. It weighs 1031 pounds with a light prop and engine, a PC 680 battery, and a lightweight alternator. I'd guess there are 40 pounds of paint, primer, and filler in the airplane. That weight could have been saved. I could get rid of 9 pounds if I swapped starters, 5 pounds if I took out the carpet, and probably 5 pounds of stuff in the panel if I switched to glass. After that, I could save another 10 pounds by eliminating all external lights. So let's say all of that stuff is 70 lbs. If I eliminated all of it, the airplane would weigh 960 lbs, or thereabouts. That's roughly Van's factory weight claim for an RV-6.

At that point, what is left is the opportunity for a lighter (than 13 lb) battery, a composite sump, and eliminating the comm radio, transponder, and intercom. Beyond that, you have to start leaving airframe components (wheel pants, wingtips, etc) behind to save more weight.
 
Using some of the new glass instruments will make a difference. When it comes available, I'll be removing my DFC-250 AP head unit, electric DG and electric Horizon - replacing with a Gemini AP. This will remove about 8+ lbs.

... or ...

going the next step and removing (almost) all of the individual engine instruments for an engine monitor. This might remove an additional 4+ lbs.

When my battery gives out, I'll be checking in with rocketbob to get his opinion on the new LiFePO4 (or similar) batteries.
 
If you are building an -8:

Grove aluminum gear

For everyone else and RV-8s:

NO PAINT! :D

Also skip the extra electrical system/backup battery. Most new glass has internal batteries to keep things powered. Unless you are running electronic ignition.
 
humptybump said:
I'm. Of sure why he other thread was closed. It may happen here too.
Click to expand...

+1 on that.

Great ideas here...glad to see this out of the box thinking. Especially like the ones that are not obvious, like Paul's suggestion of going with fewer ply tires. Fantastic.
 
When I swap my Aymur Demuth prop for the Catto, I'll be weighing them both. Depending on the delta, I may or may not remove the 12lb inertia ring.

I spoke with the original builder. He said the tipping point for him would be if the Catto were 6lbs heavier. I don't think it will be that much but I'll find out soon enough.
 
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