smokejohnson

How's it going Ron?

Sky Sharkster

Hi James,
Sorry to say I haven't worked on the glider since I put the dihedral in. I crunched my Corben Super Ace micro and have been repairing it. Should be back to the QF II in a couple of days.

Hi Brian, Thanks for the update on the kits, mine has the full-length spars. Got my Scorpion motor and Rx batteries Saturday, Thanks!

Matt, Welcome to the QF II club! Hope you enjoy the build, it's fun.
I'll be posting here soon, building goes a lot faster if you don't have to stop for repair work!
Ron

Sky Sharkster

Back to work!
Here's the hinging process for the stab and rudder. Although MM recommends packing tape, I had some clear hinge tape from Hobby-Lobby.com, so that's what I used.
First I sanded the 45 degree bevel on the rudder (yes, I'm left-handed) and elevator.
Wiped the dust off the surfaces, pinned in place.
Put tape on the side away from the bevel.
Done!
Ron

Sky Sharkster

Here's the next step on the tail surfaces; Glue in the ply control horns, for this I used thin CA so it would wick into the small joint.
Then, sand a channel into two pieces of cross-grain strip stock, glue these pieces to the stab and fin. Here I used thick CA ((Medium), these pieces provide a solid mating surface to later attach the tail to the F/G boom.

Sky Sharkster

The last preparation to the tail surfaces before joining to the boom is to add triangle stock beside the mounting strip. Two pieces alongside the elevator mount and one under the fin block. After I glued these on, I re-shaped the channel by wrapping sandpaper around the boom and using it as a shaped block.
Then, sand the rear 5-5/16" of the boom with wet sandpaper, I used 320 W + D paper. The tape is to mark the length to be sanded. Lots of carbon dust!
Here's the dry-fit of the stab and fin.
Ron

Sky Sharkster

Here's the stab glued to the boom. I used 30 minute epoxy.

Sky Sharkster

After looking at a couple more photos in the instructions, apparently there's a piece of triangle stock on each side of the fin mounting blocks. It only shows one piece on the first photo, but two later. So I added one, and epoxied the fin to the boom.
The instructions show a nifty method of using aluminum "L" stock to align the fin, but I didn't have any. So I rigged up a 90 degree triangle and eyeballed it. I'll keep checking the alignment until the epoxy cures.
Ron

Sky Sharkster

Here's photos of the fin-to-boom joint.
Next I sanded the section of the boom that joins with the pod, again 320 W + D paper.
Epoxy the boom into the fuselage.
The pod is weighed down flat and the stab aligned with the board. I also put a 24" ruler across the wing mount to aid the alignment with the stab.
The rear of the boom should be raised 3/16" above the board.

Sky Sharkster

Time to cut the battery hatch away from the nose pod. First I probed to find the join line, then cut it thru with a 45 degree angle. Next, slit the tacked-on hatch loose.
Now, the application of the 2 oz 'glass cloth (also supplied with the kit) and Minwax Poly.
Cut the 2 pieces to size.
Brush on the Minwax.
Done!

Sky Sharkster

Photos;
(1) After an over-night drying, I trimmed the excess cloth off the nose and hatch. In a few spots it had lifted, generally near the corners and edges.
(2) After brushing on a 2nd coat, I let the Minwax set up a bit, until it started to get tacky. Then I used a scrap of plastic sheet (backing sheet from Microlite) to rub the loose sections back down. I also flattened the tip of the nose, where the overlaps had bubbled up slightly.
Ron

Sky Sharkster

After a busy week at work, I finally managed to squeeze in a little work, the upper wing sheeting.
(1) First I trimmed some of the epoxy that had oozed out from the clamps.
A slight step or ledge between the doubler and spar was cleaned up.
(2) And the dihedral joint is shaped up.
(3) After a dry fit, I was disappointed to find a few slots didn't match up with the alignment pegs or "feet" that stick up. Whether this was due to not gluing the ribs in perfectly vertically, the wood swelling and shrinking (it's been alternately hot + dry, then raining here) or plain old poor workmanship on my part (most likely!), it bothered me. So I made a "slot enlarger" by trimming an emery board.
(4) Here's the fit of a couple enlarged holes. Guess I'll have to live with it.
(5) A couple more. There were 5 altogether on the right wing.
(6) Slow CA on the spar. Next I kept pressing/sliding my fingers along the spar/sheeting joint until it was dry.
(7) End view before gluing the front of the sheet to the ribs. I dripped fast CA (from the leading edge) along the rib/sheeting joint while holding the sheet in place. One rib at a time!
(8) Done!
(9) End view of right wing. Although I was wearing goggles, had a window open and a small fan going, the "fast" CA fumes were strong enough to make me glad to be done with one wing.
Ron

Sky Sharkster

Here's the left wing top sheeting, after it dried I sanded the entire wing with # 320 wet or dry, using only a sanding block. The CA leaked through the alignment holes in a few spots.
(1) Medium CA on the spar, next I'll spread it out evenly.
(2) Sheeting glued to spar, but not to ribs, yet.
(3, 4, 5) After gluing all ribs with fast CA and sanding.

Murocflyer

Looking really great Ron! You do good work. Nice build thread also. I don't think you have left one stone unturned.

Frank

smokejohnson

Agreed, nice build and thread. Thanks for sharing Ron.

Sky Sharkster

To Frank and James. thank you for the kind words. It's not going fast, but sooner or later I'll get this plane done! Haven't had the free time to really keep working on it.
It hasn't been a hard build at all, just a couple of places I didn't understand the directions fully. After I got a few steps along, they became more clear.
Just got my RX batteries in the mail, Hobby-Lobby had one backordered and it came in. Also got a couple extra from Mountain Models.
http://www.mountainmodels.com/produc...d7ebd16580b7a5
Ron

jb48

A friend of mine and me are scratchbuilding each one a QF-2. My friend made a mistake and glued the carbon tube through the second bay from rear, which means that the tail is now about 3 inch nearer the fuselage than the design spec. So instead of a distance of about 20 inch from rear of fuselage to stab, it`s now around 17 inches.
Our question is: Can this «shorter» tail moment can affect the flight caracteristic seriously? What to expect?

Sky Sharkster

Hello JB,
Well, I hate to say it, but the answer is "Yes". It will adversely effect the flying ability. You've modified the "Tail Volume Coefficient".
http://www.djaerotech.com/dj_askjd/d...s/formula.html
The size of the tail surfaces, the length of the tail moment arm, the center of gravity and some other factors (like the wing airfoil, area, tail airfoil) all work together to increase stability, control response, surface deflections and so on.
If you change any one factor (and three inches is a substantial change) you change everything.
I've never flown this design before, but have flown many gliders, from scratch, plans, kits and ARFs. Based on these experiences, I would say the shorter TMA will reduce the pitch stability, stall response, rudder response and lateral stability.
I don't know of a way to (now) increase the boom length without adding unnecessary weight, or making it too weak. At this point the most efficient way to correct this would be to remove the boom from the nose, trying to do as little damage as possible, and re-glue it in the correct location.
Sorry, but that's my best advice!
Ron

jb48

Thanks for the quick answer Ron. I`ll transmit your comments to my friend who, I think, will make a new fuselage...a one evening proposal for him.
For myself, the building of my own QF-2 is going well, especially considering that I (we) use no kit, a somewhat challenging proposal since the plans sheet drawings are intended for kit building. But with the Paul Daniel`s building manual (around 76 pages) it`s doable. More on that later on.... Thanks again.

Sky Sharkster

Hi JB,
I think building a new nose is the best solution, or making the best of a bad situation. I forgot you were building from plans instead of a kit, now you're a real "Scratch" builder!
Here's the beginning of the sequence for adding the leading edge to the wing.
(1) The sheeting is slightly oversize, sorry the first photo is blurred, but you get the idea.
(2) Another shot of the L.E. Sheeting
(3) Here I started cutting the sheet down and bevelling the front edge to mate with the angled L.E. placement. Some builders call this a "Diamond" L.E. I'm only working on a couple of rib bays at a time, starting at the tip.
(4) End view
(5) Bottom view
(6) Top view

Sky Sharkster

Another busy work week, but I managed to get in a few hours this morning. After slowly cutting to shape the L.E. sheeting (to accept the "Diamond" L.E.) a few bays at a time, I decided to try a different and hopefully faster method. Is there a tool that will remove long, straight layers of balsa, very thin sections and is easy to control? Why, yes!
(1, 2) Razor plane, shaving off extra material
(3) Right wing L.E. sheet, cut to size
(4) Front view
(5) End view
(6) Bevelling the inside edge of sheet 45 degrees, used an emery board
(7) Top view, L.E. held in place, not glued
(8) Bottom view, not glued

Sky Sharkster

Here's the right wing L.E. installation.
(1) Rubber bands, glue, wing propped up
(2) Titebond along the L.E. sheet, next I'll even it out with a toothpick
(3) Close-up of one section
(4) Done, let it dry

jb48

Hi Ron. I have 2 questions for you and/or other QF-2 kit builder(s). Since I am building a QF-2 entirely from scratch and since it will be my very first experience with discus launching glider, I will like to know how long has to be the launching pin glued in the wingtip? Same length top and bottom of the wing?
Another question concerns the rudder and elevator pushrods exit from fuselage: would it be a good idea to direct them (or at least the rudder one) tru the carbon tube? How do you intent to route the pushrods from servo arm to tail control horns? I wonder how to nicely do that part of building. Ah yes, a last question: could routing the antenna tru the carbon fiber tube be detrimental to radio signal?
Thanks a lot for your appreciated help.

Sky Sharkster

Hello JB,
I haven't gotten to the tip peg or servos yet, but according to the instructions the pushrod guides are glued inside the fuselage. Starting from the rear, about 1-1/4" inch in front of the stabilizer, up to F3, there are a couple of slots in F3 for the guides. They exit the boom (at the rear) one on each side. Depends on whether you're right-handed or left-handed. The plans have a small detail of this on the boom side view.
Here's a photo of the launching peg, it's about 2" long and 3/16" diameter C/F tube. No mention of how much sticks out on each side, but most of the DLG's have it even, top + bottom. Index finger around the top, middle finger around the bottom.
Also no mention of where to route the antenna, I plan to tape it to the bottom (outside) of the boom.
There are also 2 long C/F ribbons that are CA'd to the top and bottom spar, tip-to-tip. This is done after the wing is sheeted, will post photos soon. The peg goes through the C/F at the tip.
Good Luck!
Ron

Sky Sharkster

Here's some photos of the wing sheeting, top + bottom. I'm not too happy with my workmanship, some gaps where the L.E. angle meets the sheet. For some reason I had a hard time matching this up.

buzzbomber

Looks good to me! My kit's still in the bag, unfortunately I have a few more important non-hobby related projects holding me up at present.