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D2A-5005

Received my plans set earlier in the week. Very quick shipping, and excellent packaging.

Initial impressions - looks like plenty of information to get it built. Will take some studying to understand how things are depicted. As hand-drawn plans (from before any CAD technologies), the drawings are minimal but convey the information.

So until we have a pathfinder build or builds where many photos are generated, it's going to take a while to figure out how all this goes together.

They do include a materials list. Not a hardware list, so I'll still need to go through and count rivets, bolts, washers, nuts, etc., but the quantity of the different sheet and plate thicknesses is called out.

Seems to be very simple construction & low parts count.

I did a quick survey of A65 engines for sale on Barnstormers. Looks like it's fairly easy to get a mid-time removed-from-flying complete for about $2k. Less than that, and most of those are missing carb, mags, or both, or don't have any logs to confirm time. But at $2k-$3k for a usable engine, this could stack up to be much more affordable than other single-seat options on the market now.

Before getting too far in, though, I'll probably build a wood mockup of the cockpit to see how I fit.

Lower aft fuselage skin in paper at 30% scale. Can see now how the upper edges of the skin are bent to form longerons on each side. Pretty clever. The upper aft skin has more bends - it forms more than 3 sides. Starting to see how these are dimensioned.

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Made up the upper aft fuselage skins. The extra bend in one of the sides changes the proportion of 5-sided structure at the forward and aft ends. Also looked through the plans some more. If the welded parts were available, that would be a big time/effort saver for me. I'm not picturing how the center fuselage frame is completed since it's shown in a couple of partial views.

The gear appears as if it could use some influence from Sonex, perhaps. Copy what they did for nose gear suspension and main gear axle attachment. Comments in the Davis build guide seem to indicate some improvement could be made to the rubber donut front spring. A Sonex-style main gear axle attachment would avoid having to make the bend in the tapered steel gear leg, might allow for easier adjustment of axle toe in/out, and allows for simple addition of Azusa cable brakes & wheel pants. I'm a little surprised that in the photos for the DA5 that it doesn't have wheel pants - for such a high-efficiency / low drag machine. On the Sonex, wheel pants + gear leg fairings added about 10mph in cruise (from 140 mph to 150 mph). Difference might be even more pronounced on the DA5 since the wheels are proportionally larger.

In the wing drawings, I was trying to figure how the wing attaches. Near as I can tell, the wing is built as one piece, all the way across. The fuselage has a slot that the wing fits up into. With the fuselage set down on the wing, the wing spar is then bolted through to the fuselage frame, and the bottom of the wing spar slot is covered over with a skin. The main gear mounts in the wing. So to move the fuselage around in the workshop, I'd probably build a temporary "main gear" that fits into the wing slot.

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Eric,

Harold Davis (Leeon's son) can fabricate most any parts needed. He actually built the first DA-5 with Leeon when he was in high school. Send him an email to haroldedavis AT yahoo DOT com

Harold has a well equipped shop, does excellent quality work and is an A&P IA.

Bryan

Good to know there may be a source of some parts. I found the attached article yesterday. From 2011, and written about a DA5 built in the 1980's. Says they were selling kits, so some fixtures for the welded parts probably existed, and may still exist.

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Started mocking up the cockpit for size. If I'm going to invest the time & money, I should have a good idea whether it "fits" or not. Initial impressions - it seems big enough. I'll see if I can get representation of the actual seat position & canopy height added to this.

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Added a representation of the wing spar and seat back. It's pretty deep to get up out of, and I might really want to raise the bottom of the panel - I haven't got up out of it without knocking that cardboard panel off. Shouldn't be that big of a deal with modern all-in-one instruments to shrink the panel.

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Added the seat bottom. Comfortable angles on the seat back & bottom.

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Been a while, but I haven't been doing nothing. I've been working on a parts list / materials spreadsheet. I found a spreadsheet like this when I did my second Sonex project starting in 2005. The spreadsheet helps with material quantity planning. A big help in getting the project done comes from sorting the spreadsheet by material type. With that sort, I could go through each material and make all of the parts for that material regardless of what plans pages they are found on. This was a big help with the Sonex. After writing this posting, I find that it doesn't allow Excel files as attachments. So I'll put .pdf's when I get a chance.

File for the parts list. Had to generate the .pdf on another computer w/ a different version of Excel.

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I am so glad to see someone doing this! I have a set of plans too and I was/am mystified as to how the sheet metal was bent in the aft fuselage as well. And I agree with you about how the Sonex-designed (or a Sonerai) gear would be a better idea. Keep up the good work!

The aluminum gear may be a bit heavier but if your interested I just recently got some pictures from a guy that is building the DA-?. He was a good friend of Leeon's and they worked together this design. He is using 7075 gear legs. Maybe you can get some ideas from the pictures.

Also I posted some pictures of the DA-7 trim on the Yahoo group. Very nice design and it eliminates the trim springs.

 

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