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976.2 LB RV-8A - Lightest one ever?

judoka5051

Well Known Member
Hey All,

I just weighed my plane and it came in at 976.2 in ready to fly condition. The plane is not stripped down. It's day/night VFR with autopilot. I paid close attention to keeping the weight down. Anyone else with a RV8/A this light?


Lance
 
Hey All,

I just weighed my plane and it came in at 976.2 in ready to fly condition. The plane is not stripped down. It's day/night VFR with autopilot. I paid close attention to keeping the weight down. Anyone else with a RV8/A this light?


Lance

Will be interesting to see the weight after installation of your engine!!
 
Van's claims an empty weight of 1067# and up for an 8A. Where did you shave those almost 100 pounds at?

It is not uncommon to get a grossly incorrect weight. Not saying that these are incorrect, but I've learned to doubt all empty weight claims unless I see the planes weighed with my own eyes on known, calibrated scales.

We recently had a light plane at our airport that the logbook W&B claimed had a 461# empty weight, which I knew was awfully light. When weighed on known, calibrated scales, it weighed 525#. If I had to guess, it was either never actually weighed, or it was weighed on bathroom scales.

Not accusing anyone here on this forum, just shining a light on a very easily overlooked discrepancy. It's worth renting or borrowing known, calibrated scales. Your life may depend on it, especially if you are misled to load it outside the envelope. Ugh.
 
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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
 
Sounds great Lance!

With the items you listed in weight savings that certainly adds up to what mine weighed in at 1128 with paint and a lot of wires :eek:

Good job!
 
Great Job! (My -9 was 991 lbs on its first flight.)

I've got a few questions for you:

Which engine did you use? (Please include the dash number.)
Which prop?
Carb, fuel injection, throttle body, or something else?
How did you equip the instrument panel?
Auto fuses or breakers?
Leather or cloth?
Auto Pilot?
Parking brake?
Intercom? (Is that part of your radio?)
Manual or electric trim?
 
Hey Bill,

Here's some answers!

O320-E2D (Upgraded to 160 buy previous owner and used on an RV6)
Currently a Sensenich wood, but I'll be changing to a Catto.
Rotec TBI
Trutrak EFIS with AP, and backup 2 1/4 steam gauges
Auto fuses
Cloth
AP yes indeed! 2 axis
No parking brake... chocks
Separate intercom, the radio has one, but I don't like it.
Manual Trim of my own design. I re-tasked the aileron trim control to elevator trim.
 
My -8 has io-320, 3lb battery, dual pmags, 200rv prop/Jihoistroj gov, cloth seats/light weight crow belts, dynon glass, very thin paint, 6 qts oil in the sump plus prop/filter. Total 1092. I could see 1060, 1050. Maybe 1025 with the altered frp tips, etc. Just can't buy 976. Was there any oil in the engine?
 
Hey Bryan,

Yes, oil in the engine. If you go back and read my second post carefully you'll see there's more weight coming off than just the electrical system. I also forgot some other things I did. For one I deleted the right console and have my switches in the panel. Several switches do double duty. For instance the Nav and strobe are combined. Flip on once for all on and, then toggle off/on for strobes. I also don't have a solenoid for master power. Two reasons, one I didn't like the constant 1 amp draw, and two it was heavy. I have a manual battery switch that's a lot lighter and doubles as a key switch (another small savings). Additionally, I read something interesting in Bon Nuckolls book about not adding on/off switches for equipment that already had one. So I deleted those switches too. So buy 976, or don't, but that's what it weighs.

Lance
 
1030 lbs all in. Wrapped in 100% vinyl.

Thought I was the lightest:(

Congrats on a sure to be amazing flyer!
 
RV7-O-360-Dual EI-Catto-SD8 and Planepower 60 amp alt-Leather-Carpet-no fairings-no paint-did not build as light as possible=1038
 
NOT 976.2 any more.

Hey Guys,

I just had the planed weighed again today, this time at the A&P's shop on the field. The plane officially weighs exactly 975 lbs with wheelpants and all.

It lost another 1.2 lbs when I went through the W&B numbers and realized that I had a more aft CG than I wanted. So I removed the ELT from back there and was planning to move it forward some. Well, it sure felt heavy, plus I couldn't find a place that I liked; so I replaced it with an EBC 502 moved to the area between the seats on the left side. I also pulled the sticky feeling manual trim (of my own design) and installed the Ray Allen system.

After all that, it still has a more aft CG than I'd like (limits aft baggage). I guess you can get too carried away with a weight loss program!
 
I'm at 1080lbs with Paint, all pants and fairings, an IO-360 (parallel valve), a Constant Speed prop (WW 200RV), fire extinguisher and oil.

I've managed to maintain that pretty well over the last 6 years. I added a pitch axis to the AP, but switched to LiFePo batteries, removed the last mag in favor of a second lightspeed, and switched to a Beringer nosewheel.
 
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:rolleyes:
 
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
 
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.
 
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.
 
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 :)
 
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