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Apr 02, 2019, 08:35 PM
demondriver's Avatar
I love the Cinder-Block Sandwich wing method Sir! Your really making solid Progress! keep this up and you'll have her in the air this summer!
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Apr 03, 2019, 01:35 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Yes sir, I hope so. Now waiting to get a 5/16 basswood spar from Hobby Lobby (craft store) to finish up my incidence meter. I have been very ill the last couple of weeks and managed to get better (no big deal, no long-term issues). Haven't been able to do much of anything.

Opening in the parts is 8 mm and this should match up perfectly.
Apr 03, 2019, 11:01 PM
It's a fine fiddly business.
Robert R's Avatar
DD and Kevin. It is good to hear from you both.
Apr 04, 2019, 12:28 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Same to you sir... Just getting through some health issues right now. I stumped my GP last week when all the glands in my face and neck were swollen... not the mumps though. Gotta have a procedure next Thursday too...
Oct 14, 2019, 12:24 PM
AMA 986339 FCC KB5LAM/4
davidterrell80's Avatar
Praying all is well.
Oct 14, 2019, 06:07 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Thanks David, I appreciate your prayers. Had some more things going on, much better now.

Update. I have two Robart incidence meters, one I converted to a phone setup. They work well.

Still need to continue to work on incidence of the wing.

Maybe I can get back out into the shop soon.

Frankly, I don't know how well it will fly. I made some boo boos along the way, mainly with the wing. I have learned a bunch though. I do have a person helping me to make it flyable; he is very qualified to help.
Oct 19, 2019, 07:14 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Now attaching control surfaces. I need these attached and secured to set the horizontal stabilizer and wing incidence. Working with someone, we figured 1.5 positive on the wing, 0 on the stabilizer.

The stabilizer fits snugly into a cutout at the proper angle, so I'll be gluing that up soon, using the wing attached for tramelling. Initial measurements with strings show it very close.

I'm short two hinges, so I'll get the last aileron attached late next week. Once that is set, I'll secure the control surfaces so I can place the incidence meters. I converted a Robart 404 to work with my phone with this part. Seems to work well.
Oct 26, 2019, 07:36 AM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Not much to report, but here goes...

Picked up a nice solid Turnigy 3000 mah 4S 40 C battery, should work well for the power set up. An earlier test with the same spec battery showed plenty of power, even at 80% throttle.

I may be able to use 9050x3 props, as the club now has a Bad Boy ZTR mower, and it cuts the grass so low I can fly off the runway with 1.5 inch tires. I have some 8040x3 props, but I think the 9 inch will do better if we aren't in grass cutting mode. Test taxiing will show us where we are.

All control surfaces except rudder have been attached. Gaps are not as good as I would like them to be, but with the performance envelope of this airplane they should be ok.

I'm waiting on some parts to arrive before I can attach servos to the control surfaces. Once this is done I'll be able to focus on getting the wing and stab incidences correct. I still have some issues with the wing; I will be able to evaluate these better once I have control surfaces secured and I can run the incidence meter down the length of the wing to check various points.

The curved surfaces on the wing and stab will make getting them aligned a bit tricky, but I should be able to id and mark reference points by measuring off the fuselage.

Probably too late to maiden this year, so I'll work on finishing her up for the spring. No paint work until I know she flies ok. With a wing cubic loading of 9.5, she shouldn't need to scoot along fast to fly, stall speed should be around 17-19 mph.
Nov 11, 2019, 07:37 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP

Flaps - Not Real Happy With Them

Connected up flaps today, I'm not real happy with the hinge outcome. Some play in them, they seem to flex a bit too much for my liking. Might have been better to use heavier-duty ones. I dropped some Titebond II into the area where the hinges go into the attachment point just in case it didn't get them filled in. I see the hinge plastic flexing, so I'm not confident it will help.

The hinges were inserted at a 45-degree angle into both the flap and mounting point.

This won't be any kind of speedster, but I need to make sure I avoid flutter.
Nov 29, 2019, 05:44 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP

--> Update

I was able to use some Titebond II to build up the exposed hinge area. No significant flex now so they should be good.

I attached the control rods today, I have about 3/8 inch up and down motion with the default 100 % endpoints on the ailerons and elevators. Flaps have 22 degrees on first down position, 44 degrees full down. I can dial in a lower endpoint if this is too much.

Next up is to glue the horizontal stabilizer in place. This will give me the baseline to set the wing incidence.
Nov 30, 2019, 05:42 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP


Since the control surfaces are installed, it is time to align the horizontal stabilizer to the wing. The stabilizer will be glued in, and it has alignment pins.

To get the fuselage stable and prevent it from moving I used a small styrofoam ice chest and a ruler to shim it up under the wing box with a couple of tie-down straps to hold it steady. Incidence meter over the wing area of the fuselage shows 0, and with a bit of shimming of the stabilizer it shows 0. Measuring reference points from the stabilizer to the wing has them within 1 mm. Good enough, I'm happy the way this is looking.

Wing is at 1.5 degrees positive incidence, right where it needs to be.

I'll do some gluing of the hard points on the stabilizer to set the alignment, then when dry add pieces underneath the stabilizer for strength and shape. Small pieces on the top of the stabilizer will fill in to the fin; still need to make those.
Dec 08, 2019, 10:16 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Had a flying buddy come by and check my findings, all good.

Horizontal stabilizer has been glued into the hard points, including filling the gap between the stab and fin. The gap was a result of having to cut some underneath to get the stab incidence right.

Checked motor down thrust, 3 degrees on both, no side thrust. We'll go with this on maiden.

I'll be working the underside stab blocks first, as they have the proper transition into the tail end. I can then fashion up the topside stab blocks to match the underside transition. This is going to be very strong.

I need to laterally balance and fill in a few seam gaps on the wing, plus a bit of tip shaping.

Once the tail area is complete, on to grabbing my 3000 mah 4S and setting CG. I hope the battery position will be somewhere over the battery box.

After that I think she's ready for taxi test and possible maiden. If New Years Day is nice enough amd I have her ready we'll try for that.

Looking back, it has been almost 7 years to the day I began this build. I have the utmost respect for anyone who designs now. So much you need to know...
Dec 14, 2019, 04:18 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Glued in the shaped blocks on the underside of the horizontal stabilizer. The 4-0-4 has most of the area in-line with the stabilizer underneath, unlike similar Convair aircraft. The blocks are solid carved, matching the one-piece spine, the bulkhead, and the underside of the stabilizer.

They went in nicely with minimal gap all around. I did some more shaping after the glue dried, I'm happy with the results.

Next up is righting the fuselage and carving out pieces to go on top of the stabilizer. They'll go up against the fin, and they will be solid just like the bottom pieces. That has the caboose done, then it is on to placing a battery to find CG. it should be about 95 mm from the leading edge. I'll confirm that number.
Dec 14, 2019, 05:07 PM
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Dirty Dee's Avatar
Getting closer!
Dec 14, 2019, 05:29 PM
A Day @ a Time - Matt. 6:25-34
ruff1's Avatar
Thread OP
Ooops, forgot I need to install the rudder and control wire, then on to CG. That's up after the pieces that go on the top of the stabilizer.

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