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Old Jan 20, 2007, 07:41 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
Fuselage

Well, back to business... I'll post about the Dragonfly tomorrow on another thread if I get to fly it.

I have the lower tray in, along with the wing saddle and the nose block. My nose block is laminated from 4 pieces of 1/4" poplar, with a couple of pieces of 1/8' bass added on the sides for fill. It may be a bit hard to see but the lower tray is parallel with the wing saddle until it gets to the front of it. Then it bends down to meet the nose block in about the middle. It's already got the cutouts for the radio gear. I don't have a piece of wood big enough for a full block canopy so I may have to improvise, some... The control system has to be worked out next, and I need to get out my table saw so I can make some diagonal grain triangle stock. After the control system and aft bulkheads get installed, I'll do the wing bolt system, and then close up the bottom. I ended up with 5/8 clear space for the ballast bar area. I figure that a bar of sheets that are 5/8 X 1 X 8.5 will be enough ballast for this beast. Again, these will be made from sheet lead and will go in flat. That way they can be balanced and not effect the CG. If they're 1/16 thick, that gives a lot of flexibility in the weight gain department. The wing bolt will go down through them to keep them from shifting the CG. I never heard anything back about that balast system, so I am assuming it's acceptable...
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Old Jan 20, 2007, 07:47 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
A bit more...

This fuselage is still just a bit fat, so I'm probabaly going to take just a bit more off the bottom of the front area, beginning just behind the battery, and ending about mid-wing. Probably only 1/4" or so, but that sometimes makes a real difference in appearance... My wife says my fuselage could use some slimming down, too... wonder what she means by that?
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Old Jan 20, 2007, 07:59 PM
Flying = Falling (Slowly)
dharban's Avatar
Tulsa, OK
Joined May 2004
2,491 Posts
Nice workshop Jack

Don
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Old Jan 20, 2007, 08:07 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
Oh... it's so warm in the kitchen... and SOOOO COOOLLLLDDDD in the garage... shoulda never left Houston. However if I was still there, I'd be rantin' about the freakin' traffic... Beginning vertical tails tomorrow. I have to make templates so don't expect it to go too fast... Delores just threw in a bathroom tile project, too. AAAAAHHHHHH!!!!
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Old Jan 21, 2007, 09:06 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
Main Wing Bolt...

This needs to be done accurately... and while that should go without saying, keep in mind that some inexperienced folks may be looking through this. I start by drilling the center for the bolt head with a Forsner bit. In this case it's a 1/2". I went a touch deep but there's plenty of 3/4 laminated plywood rib under there, so nothing's realy amiss. I may decide to go to a 1/4 X 20 allen-head, steel bolt when flying with ballast. Next I used a sharp, 1/4 Forsner bit down through the center of the larger hole, and out the bottom.

Here's how she looks. As you can see, I had no 48" wood so I did a bit of splicing...
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Old Jan 21, 2007, 09:16 PM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
The fuselage part...

... needs to be done now. Trying to do it later would have you sending me hatemail and grams...

Under the tray, I put in a piece of 1/4" poplar, cross grained to the fuselage. I tapered it... just because... and fit and drilled it before gluing. I had to measure carefully because the fuselage needs to be drilled from the bottom up. That way the wing saddle can sit flat on the drill press and you won't be trying to prop things up to get a straight hole. Measure twice, and drill once... again with a sharp Forsner bit... 1/4". Go ahead and drill the cross-grained, poplar nut brace when you drill the fuselage. Check with the wing and the bolt to make sure you're centered. Now use a 5/16" bit to ream the bottom hole only, so the 1/4 X 20 Blind nut will slip fit. Leave the hole in the wing saddle at 1/4" so it will index the wing properly as you assemble it. I went ahead and marked my brace and drilled 1/16 holes for the blind-nut keepers that penetrate up into the wood, and prevent it from turning under torque. Now epoxy in the brace, sparingly around the hole, and add just a touch of epoxy in the holes for the blind nut. Place the wing on with the bolt and tighten it up. That will clamp the cross-grained brace until the epoxy is cured.
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Old Jan 21, 2007, 09:26 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
Back Bolt

The back bolt will be done tomorrow night. I can't seem to find the smaller bolts I have for that purpose... they're here somewhere...

Anyhow,,, the first glider sounds were emitted from my garage this evening... ... Couldn't resist puttin' the wings on. I didn't do anything else except getting the control system figured out. It's pretty straight forward. Gotta make some bulkheads for the aft portion to stiffen it up a bit.
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Old Jan 21, 2007, 09:37 PM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
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One more detail...

The ballast box gets penetrated by the bolt, as I have said before. This pic is a bit blurry, but it should give you a better idea of what we're trying to accomplish... Remember... it's gotta be accurate!
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Old Jan 22, 2007, 10:38 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
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No back bolts...

... tonight. I can't find them. I am going to Lowe's tomorrow anyway, so I'll pick some up...

Anyway, I started the bottom of the fuselage nose this evening. We'll look at properly made corner blocks, and discuss why we'll be able to make those pretty curves. First look at the block. Notice that the grain runs diagonally across the joint it's going to reinforce. If we are going to shape this thing out right, the wood's going to be sanded down to the joint so that instead of a 1/4" wide glue line, we may sand past the glue line altogether. It's already strong enough along it's length. It needs to be heald together. If we just use triangle balsa stock, we'll be repainring the splits so often that I'll be getting hate mail... can't have that...

These are just 1/4" sheet and were done on my jigsaw. They're not as clean as the ones I do on the table saw, but it's too cold to get it out...
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Old Jan 22, 2007, 10:55 PM
Hot Dawg Glider Pilot
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United States, TX, Weatherford
Joined Nov 2002
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The nose...

... is done on the bottom with 1/4" cross-grained hardwood. In this case, poplar, like the nose block. It's plenty strong and we're adding weight where the strength is needed... my mantra... On the other side, the inside, are the corner blocks. In the nose, they're poplar, too. The hardwood goes back to the aft of the servo cutouts. It's balsa from there on, with 1/8 ply added in the tow hook area. We'll get to that.

Be sure of the fit. I used epoxy on all the stuff forward of the trailing edge. But no amount of glue or putty will make up for a poor fit or sloppy work. That makes it weak and heavy, while we want it strong and light.

At the trailing edge of the wing, we stop being so particular and just use triangle stock...This will be one tough fuselage, and it won't be too heavy. The weight is building, but remember... there's going to be lots of carving and shaping. Besides, this is the nose... better strong stuff than lead... right?
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Old Jan 22, 2007, 11:04 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
Sorry...

... it's taking so long. Between documentation and weather, I'm surprised I'm this far along. It's amazing what I have to do just to get a little epoxy to cure...
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Old Jan 23, 2007, 06:41 AM
Make Flying Fun
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United States, MD, Lutherville-Timonium
Joined May 2003
1,451 Posts
Hey jack, did you say that the triangle stock in front of the trailing edge is hardwood ? Great thread...thanks.
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Old Jan 23, 2007, 07:28 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
The first 7" or so from the nose block back is hardwood, both the bottom and the triangle stock... nice for those "landings"... It is still cross-grained but goes to balsa at the aft edge of the servo cutouts. So does the bottom sheeting. It will be cross-grained balsa to the trailing edge. In the towhook area, there will be a piece of 1/8 plywood on top of the 1/4 balsa, with a 1/4 plywood insert right around the hook. At the trailing edge, the bottom and the triangle stock will be normal with the grain running lengthwise. May not need much lead to balance...

Hope that helps...

Jack
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Old Jan 23, 2007, 11:04 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
Tow Hook

If you want an adjustable tow hook... and who doesn't... This little section of fuselage is important. It's actually 3/8 thick, and has the cross-grained diagonals, and just enough room between for a plywood/blind nut. Here's what it looks like. This hook is actially for my Hawk, and I'll be using one from Hilaunch, but the slot's the same size. I started by figuring out where the tow hook should be, and cut about a 4" section of 1/8 plywood to fit that portion of fuselage. I marked the center, and made a 1/4 ply insert for the bottom. That prevents the nut/washer on the bottom from crushing balsa. Mark the center of that, and glue them together. When dry, make your slot for the hook to travel fore and aft. Add the 1/4 balsa filler to the bottom, surrounding the insert, and you're done... oops... we also need to add the triangular bracing. This one won't pull out of the fuselage... or at least I don't think it will...
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Old Jan 23, 2007, 11:18 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,744 Posts
This assembly...

... gets epoxied in and then the rest of the bottom fore section can be completed to it. It's much easier to add the diagonals after the bottom pieces have been fitted, and before they're glued. They will look like the tow hook section and there's lots of glue area there. The 1/4 bottom sheet will be flexed a bit due to the bottom contour, but the diagonal stuff will flex with it, unlike plain triangle stock. The tow hook section needs to be epoxied in. In my opinion, the entire nose section, from the trailing edge foreward, should be built with 30 minute epoxy, or perhaps West Systems or whatever slow-setting, deep-penetrating epoxy you choose... none of that 5-minute stuff...please...
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