zolotiyeruki

5 hours ago, zolotiyeruki said:

As an aside, I've also wondered what would happen if you got really ambitious and built giant molds for fabricating a monolithic wings-and-spar combination. You'd lose trailerability, but also a bunch of overlapping spar length, the wing attach bolts, etc.

I couldn't get the idea out of my head, so I dug into the plans and made a first pass at determining how much weight could be saved.  It's...not much.  Between the LWA's, extra spar caps, extra shear web, reinforcing layers of glass for the LWAs, hardware, etc, it looks like you'd save a whopping 10 lbs.  And in the process, you'd have to do some design rework--the spar caps on the wings are aft of the spar caps on the center section spar, so you'd have to rework the wing design to move the spar caps forward of the shear web, and that sounds like an awful lot of design and fabrication work to save 10 lbs.

And further into the weeds, the wing's top spar cap is 7 layers of UNI tape, compared to 5 on the bottom.  Is that connected with the g limits of +3.8/-1g listed in the POH?

I'm pretty sure you can sign up for a free account at HBA, although there are paid options to help support the forum.

Below is a quote from the linked post.  The short version: for the size airplanes we're talking about, the wing weight is a few (~3%) lighter using a massive foam core and moldless construction, vs a molded wing with the same dimensions.

So if you're thinking of doing it for weight savings, hollow wings won't do it, and as Marc says above, vacuum bagging the other parts will save some weight, but not a ton.

If you're looking to make more than one copy of a part, and want to reduce the amount of time for filling/sanding/paint prep, then the molded approach may be more attractive.

Quote

I was not talking equivalents for a 60 knot Vne airplane. The OP talked about a replacement wing for the Luscomb. Luscombs have a Vne much higher than the Aluminum Dragon and have been flown upward of 180 knots. No one is admitting to this illegal flying, but a rewinged Luscomb should probably be designed for that. When q is 9 times higher, you need a lot more torsional stiffness to keep flutter at bay. When you design for the upper end of an improved Luscomb, you must have a much stiffer structure and much stiffer skins. For a 900 pound airplane with a 1500 pound gross weight that must survive at three times the airspeed and 9 times the dynamic pressure, the wing areas may be close, but there is a lot more glass in spars and skins than you might use in your foot launched glider. In the OP's airplane range, he will usually save weight with massive foam cored wings.

Let's run some numbers. Let's say a 48 inch chord, 15% thick, one foot long piece, for a fast airplane. Flaps and ailerons are 25%, so the wing proper is about 70%, let's say 33.6" with a 7.2" thickness. Total cross section area is about 219 in^2 and our foot long piece is 2632 in^3.

Spar is the same for both. Let's say 8.16 in^2, 97.92 in^3, and 4.70 lb.

The rest of the approximations: Full cross section is about 80% of spar depth times chord of the piece. Perimeter of the piece is about 2.2*chord of the piece - we have an overlap at the leading edge for bonding and a drag spar to close out the back edge. Glass-epoxy and adhesives are about 0.048 lb/in^3. Blue foam is 2 lb/ft^3. PVC foam is 8 l/ft^3.

Skin of the solid cored section is 3 UNI, about 0.022 thick, so 1.63 in^2, 19.51 in^3, and 0.94 lb;

Foam is about 183.75 in^3, 2205 in^3, and about 2.55 lb;

So the solid foam wing is 4.70 + 0.94 + 2.55 = 8.19 lb/running foot.

Now for foam cored skins. The outside is still 3 UNI, the inside is 2 BID, total thickness is 0.045", 3.33 in^2, 39.92 in^3, and 1.92 lb.

Foam cores are about 18.48 in^2, 221.8 in^3, and 1.03 lb.

Next we have adhesives. Each side of each spar has a glue line that does not exist in the solid core wing. I get about 0.36 in^2, 4.32 u\in^3, and 0.21 lb.

Flanges are applied at the leading edge and at the drag spar. I get 16 plies 2" wide and 0.009" thick for 0.29 in^2, 3.46 in^3, and 0.17 pounds.

Ribs, are still needed, let's say one is used every three feet. Each will have about 171 in^2 of area, and they run about 0.5 lb/ft^2, or about 0.59 pounds. Each one foot section has about 1/3 of that or about 0.20 pounds.

Each rib also has flanges, I count 10 plies per rib 2" wide and 0.009 thick, at about 0.75 pounds per rib or 0.25 pounds per running foot - Yeah the flanges weigh as much or more than the ribs themselves. Seen it over and over.

Hmm, 4.7 + 1.92 + 1.03 + 0.21 + 0.17 + 0.20 + 0.25 = 8.46 lb/ running foot.

I have run these sorts of numbers over and over. In faster airplanes - where you can justify a 100% composite structure - massive foam is lighter. In an airplane with much lower wing loadings and tiny q, the composite amount drops, but the foam amount won't and yeah, the foam might weigh more than the internal parts to replace it. But not in faster airplanes.

Billski

As an aside, I've also wondered what would happen if you got really ambitious and built giant molds for fabricating a monolithic wings-and-spar combination. You'd lose trailerability, but also a bunch of overlapping spar length, the wing attach bolts, etc.

LONG EZE PROJECT • AVAILABLE FOR IMMEDIATE SALE • Long EZE Project, Major Fabrication Completed - Needs Instruments/Engine • Contact Gary Hall , Owner - located N. Lauderdale, FL 33068 United States • Telephone: 954-979-9494 Txt only

COZY MK IV 2004 • $79,000 • PRICE REDUCED • 2004 Cozy MK IV, 465 TTSN on Airframe and Engine, Lycoming IO360 , New Cato 3-Blade Propeller, 70 TT, Original Performance Prop Included as Spare, Garmin 250XL GPS/COM, ICOM IC-A200 COM, Garmin GTX 327 Transponder, Engine Instruments All Electronics International, New MGL Avionics EFIS Lite 8,5 Inches Touch Screen, ELT 406 MHZ with new battery, Extremely well built, Went 3rd at Oshkosh 2011, Canopy Cover Included, Professionally Maintained Last 10 Years, No ADSB.Price is in U.S.$. Canadian annual inspection just completed. • Contact Benoit Magnan , Owner - located St-Jean-sur-Richelieu, QUé J3B 8T6 Canada • Telephone: 514-833-4093 • 450-357-1257 • Posted September 6, 2023 

1 hour ago, mrphyslaw said:

Defiant project on barnstormers, no photos.

https://www.barnstormers.com/classified-1330181-Defiant-project.html?catid=18671

That listing has been on Barnstormers for years and years.

COZY III • FOR SALE • Cosy 3/Classic project. Lots of parts. 90% done, 90% to go. Asking $7,500 obo. Due to (insert excuses here), I have decided to sell the Cozy 3 project. Its on its gear and has the strakes, both wings and the canard. A lot of metal parts and a European (wider) style canopy are included. I’ll also include what foam and resin I bought. Asking $7,500 obo in South Bend In. • Contact Spencer Boesch , Owner - located South Bend, IN 46614 United States • Telephone: 5748507726 • Posted September 3, 2023 

Someone took Ryszard's forum about canard pricing at Airventure seriously:

AN EXCEPTIONAL LONG EZ • $125,000 • RARE OPPORTUNITY • N316NM, is one of the highest performing and well built Long ez's on earth. 200hp on board and every luxury available. • VISIT MY WEBSITE • Contact Nathan Mullins , Broker - located Converse, TX 78109 United States • Telephone: 6155453776 • Posted September 4, 2023 

9 hours ago, Marc Zeitlin said:

Hahaha. It's cute that you think that Burt had "plans" for any plane that didn't become an RAF product... There were no "plans" for SS1, for Cthulhu's sake.

You're right, "plans" isn't the right word.  Perhaps "designs" would be more apt?

IFR RUTAN LONG EZ N974EZ • $49,900 • FOR SALE • Rutan Long EZ. 1400 hrs airframe time. Dynon HDX w/ EMS, ADAHRS, Rem Magnetometer, GPS, dual-axis A/P, stereo intercom & VHF Transceiver, dual-band ADS-B in & out, AOA pitot probe. Garmin GPS175 IFR navigator, VAL NAV2000 VOR/ILS. Electric pitch trim & nose gear retract. Lycoming O-320-E2D with carb heat, dual Electronic Magnetos, 400 hrs since top end Overhaul. Includes aircraft cover, tie downs, gust locks & exhaust port plugs. • Contact Charles Bretana - ARETE INDUSTRIES LLC , Owner - located Prescott, AZ 86305 United States • Telephone: 8052080080 • Posted September 2, 2023

I want a Catbird, too.  Anyone here have an "in" at Scaled?    I heard a story a while back that new hires get to paw through all of their old records, and that includes plans for all of Burt's unpublished designs.

Kent's post from 2021 is still valid.  The plans are available on this forum for free

AREOCARD -COZY • $2,500 • ACCEPTING OFFERS • fuseleage, windshield fron wing landing 3 pod • Contact Rance Evans , - located Newburgh, IN 47630 United States • Telephone: 18124577815 • Posted August 16, 2023 •

COZY-3 PROJECT FOR SALE • BUY IT • BUILD IT • FLY IT • Amazing opportunity to build your own Cozy -3. I have the kit and I am available to answer all questions regarding the Cozy -3 kit. • VISIT MY WEBSITE • Contact Murdo Cameron - CAMERON AIRCRAFT , Owner - located Post Falls, ID 83814 United States • Telephone: 208-699-7518 • 208-640-1620 • Posted August 14, 2023

This one was also cross-posted to Facebook:

COZY MKIV PROJECT • $7,000 • AVAILABLE • Time for the project to head out of my garage and into the hands of a builder! • Contact Trevor Orr , Owner - located Cupertino, CA 95014 United States • Telephone: 14088775829 • Posted August 14, 2023

No photos, but if you're near FL:

LONG EZE PROJECT • AVAILABLE FOR IMMEDIATE SALE • Long EZE Project, Major Fabrication Completed - Needs Instruments/Engine • Contact Gary Hall , Owner - located N. Lauderdale, FL 33068 United States • Telephone: 954-979-9494 Txt only • Posted August 9, 2023

COZY MK IV 2004 • $85,000 • FOR SALE BY PROUD OWNER • 2004 Cozy MK IV, 465 TTSN on Airframe and Engine, Lycoming IO360 , New Cato 3-Blade Propeller, 70 TT, Original Performance Prop Included as Spare, Garmin 250XL GPS/COM, ICOM IC-A200 COM, Garmin GTX 327 Transponder, Engine Instruments All Electronics International, New MGL Avionics EFIS Lite 8,5 Inches Touch Screen, ELT 406 MHZ, Extremely well built, Went 3rd at Oshkosh 2011, Canopy Cover Included, Professionally Maintained Last 10 Years, No ADSB.Price is in U.S.$ • Contact Carole Morrissette , Owner - located St-Jean-sur-Richelieu, QUé J3B 8T6 Canada • Telephone: 514-833-4093 • 450-357-1257 • Posted August 9, 2023 

This Vari showed up on Facebook: https://www.facebook.com/marketplace/item/1149629756051965/

IFR RUTAN LONG EZ N974EZ • $49,900 • FOR SALE • Rutan Long EZ. 1400 hrs airframe time. Dynon HDX w/ EMS, ADAHRS, Rem Magnetometer, GPS, dual-axis A/P, stereo intercom & VHF Transceiver, dual-band ADS-B in & out, AOA pitot probe. Garmin GPS175 IFR navigator, VAL NAV2000 VOR/ILS. Electric pitch trim & nose gear retract. Lycoming O-320-E2D with carb heat, dual Electronic Magnetos, 400 hrs since top end Overhaul. Includes aircraft cover, tie downs, gust locks & exhaust port plugs. • Contact Charles Bretana - ARETE INDUSTRIES LLC , Owner - located Prescott, AZ 86305 United States • Telephone: 18052080080 • Posted August 7, 2023

FOR SALE LONG EZ PROJECT • ACCEPTING OFFERS • For Sale – Long EZ project. Would like to sell everything as a package. • Contact Jeff Sobel , Owner - located Montpelier, VA 23192 United States • Telephone: 804-852-8264 • Posted August 3, 2023

Thank you for your efforts in keeping the forum running, Jon!

A Cozy Mk IV - N141MD  Apparently ran out of fuel, landed on a road, and a road sign damaged a wing.  Has a new wing and passed CI in March 2022.  Current bid is $25k.  Oddly, the listing doesn't have any recent photos, and includes a spec sheet for...A Corvette?

https://www.ebay.com/itm/325740222552?

This seems like a pretty good deal, what with the included engine and all:

https://seattle.craigslist.org/see/avo/d/seattle-long-ez-o-230/7644443697.html

This one doesn't come with any photos:

LONG EZE PROJECT • AVAILABLE FOR IMMEDIATE SALE • Long EZE Project, Major Fabrication Completed - Needs Instruments/Engine • Contact Gary Hall , Owner - located N. Lauderdale, FL 33068 United States • Telephone: 954-979-9494 Txt only • Posted July 14, 2023