976.2 LB RV-8A - Lightest one ever?

[Bruce]

Lance,

Can you tell us about priming.

Rivet lines only or all.

Great Job.
That is what I will be shooting for.

Should be fast and agile

[judoka5051]

Hey Bruce,

The interior is all primed. If I were not near the ocean I probably would only do the rivet lines. I wonder what that would have saved?...

Lance

[SHIPCHIEF]

Lance;
I just found your thread when I searched the archive for "lightest".
My RV-8 weighed 1097 before the first flight, sans wheel pants.
I have some of your light weight ideas, and powered my ship with a carefully crafted Mazda Turbocharged Rotary Engine. Considering the cast iron turbo housing and a water filled radiator, I feel I did well.
Now I've decided that flying the plane is more to my liking than continued engine development, so I'm aiming for the lightest O-360 powered RV-8 that I can reasonably make.
Thanks for the improvement list and the contributions it has attracted.
I recently received a Personal Message regarding my 3.5 lb alternator post encouraging more info on weight savings, so there are many who continue to follow VAN's advise for a lighter, better flying ship!
I hope more contributions will be posted.

[kjlpdx]

true performance based on weight includes a pilot, that's the real number.

[David-aviator]

Originally Posted by judoka5051

I do know where the weight was saved. I guestimated the weight pretty close considering I had a pretty good idea of what a standard, simple RV8A weighs.
I should have posted what I did to shave all that weight off. I'll do it now...

Most of the weight was lost in the electrical system. I used a Lithium battery at 4 lbs, a skytech 6.4 lb starter, an B&C SD20 alternator (only), LED lighting everywhere, including strobes (so no strobe pack). A lightweight 2 1/4 Trig transponder, lightweight 2 1/4 radio. Since I used used a light battery, I was able to put it up front and used short cables. My entire electrical system demand is right at 10 amps so the alternator will never be stressed.

I also installed dual PMags which are quite a bit lighter than standard mags.

Just those items saved me about 65-70 lbs.

I deleted the ventilation system and installed rotating vents directly in the fuselage. Expensive at $95 each, but save a lot of weight (in relative terms).

My project came with the "Batwing" wingtips. I shortened the wingtips and squared the back of the tip. That saved 6 pounds.

I didn't paint it and I'm not going to. It's getting polished. That's about another 25 lbs.

It goes on and on like that, but you get the idea.

The plane was weighed with the pants on and ready to go.

Hope this helps someone, Lance

Lance,

Your weight is believable, it just takes focus on building a light weight airplane. You've shaved a pound here and there and it adds up in the end.

My only thought is on no paint, all polish. I had my machine painted where polishing is difficult, like the bottom of the wings and fuselage, also cowling pink fiber glass is tough for me to live with. As best I can tell, the painted parts added 9 pounds.

That being said, I've decided to paint the top of the wings also. The glare of the sun off of a bare aluminum surface in flight is a hazard, it can blind the pilot.

Nicely polished airplanes are pretty, but not very practical. The weight saving of no paint certainly adds to the effort, but like everything else it comes at an inconvenience.

[SHIPCHIEF]

Kevin is right about pilot weight (and weight of junk in plane).
My 108lb wife is a climbing fool in her 160HP RV-4!
I've lost 35lbs since last New Year. 15lbs to the target weight.
I weighed the original 50 amp Delco generator on the bathroom scale: 15lbs! It's easy to save 8.5lbs right there, possibly 12.5lbs.
Anyway, I don't think it would fit above / in front of the Superior Cold Air Sump's forward facing injector, and still have room for an air box.
My 8 has painted fiberglass and the cowl deck in front of the windshield. The rest is polished. I'm working with an arrangement of hats, sunglasses and different course headings :-)