Sky Sharkster

Hi Matt,
Thanks for the kind words, I'm pretty picky about my building and my own worst critic! But overall it's coming along OK.
I know about the non-modeling time, seems every time I get some spare minutes, another "chore" or errand pops up. But I hope to have this done before the cold weather sets in!
Hope you get to yours soon, it's a fun build and not difficult at all.
Ron

jb48

Yesterday night, I just completed the building of my QF-2, entirely from scratch (sorry no picture at this time). I made my very best to keep weight as low as possible, following the plan sheet and reading Paul Daniel`s building manual. I was aiming for 8 to 8.5, 9 oz at most.
What a deception when it tipped the scale at 340 grams (12 oz), including a 7 grams lead ballast in the nose.
The heaviest component is the rx battery (4x750 mAh AAA nimh cells) which tips the scale at 51 grams (1.8 oz), the 2 servos are Hitec 55 (around 9 grams each), the receiver is a 11 gram Berg Micro Stamp. Covering is standard Monokote left from previous project, weighting 1.06 oz (wing before covering: 127 grams (4.48 oz); wing after covering: 157 grams (5.54 oz). Tail and fuselage are fiberglass covered per instructions but not painted.
What I would like to know is: what is the flying weight of a completed kit built QF-2, compared to the advertised 7.5 to 8 oz.
My only departure from the plans specs is the carbon fiber rod; mine is a 8 mm rod and I read somewhere that the kit furnished rod is a 6 mm tapered rod. But that cannot explain such a weight difference, I think.
I`ll make my first gliding tests today, if the wind calms down.

Sky Sharkster

HI JB,
Wow, you built your glider fast! I'm still struggling to get mine done. But I only have a few hours on the weekend to work on it.
From your description I can see where about 1-3/4 ounces came from. The battery is larger than recommended by MM. I ordered their 370Mah 4-cell, it weighs 32 grams. This is 29 grams less than the 750 Mah battery.
And Monokote is much heavier than Microlite;
http://www.wattflyer.com/forums/showthread.php?t=10443
The "Micros" (Solite, Microlite, Nelson Litefilm) weigh about 1.9 grams per square foot. With a wing area of 1.88 square feet, this would result in a covering weight of 3.54 grams to cover one surface, twice that weight to cover the top + bottom= 7.08 grams.
Monokote weighs between 5.5 and 7.5 grams per square foot, depending on the color. Your net weight gain for covering was 30.0 grams.
30.00 grams covering weight, Monokote
7.08 " " " MicroLite
------
22.92 grams difference in covering
29.00 grams difference in battery weight
----------
51.92 grams

I don't know if you want to strip off the wing covering at this point and re-cover with Microlite, but doing that and using a smaller battery would knock off nearly 2 ounces.
I didn't weigh my stock F/G boom before I glued it to the nose, so can't say if your boom is heavier.
I would guess that your model will fly OK at that weight, but may not thermal as well as a lighter model.
I'll keep you posted on my weights as I finish my model, I'm hoping to keep it near the published weights, but you never know!. I'm planning to use the same Rx and servos as yours.
Ron

jb48

Thanks for your answer Ron. I agree with you about the weight saving from a lighter battery pack and Microlite. For the 8 mm (5/8) carbon tube I used, for 22 inches its weight is 16.23 grams. I have a carbon fiber arrow blank that is 7/32 diameter and that fits exactly in the 8 mm carbon tube. I first thinked about cutting the bigger tube at the fuselage exit and glue the smaller tube in the remaining piece up to the tail to save some weight. But I made calculations that showed it was not worth the the work involved: surprisingly, the most weight saving from the swap would be only 3.38 grams (1/9 of an once) and that would be for the entire 22 inch length!
So, I think I`ll try harder to find a real light battery pack and recover the wing with something real light.

On the other hand, I made about 25 short test flights. I hand launched in a straight line for about 15 flights and tried discus style launchings about 10 times. On every discuss launch (my very first experience on this particular technique), the glider climbed to about only 30 feet at most and finished the climb flying inverted over the top every time! It was easy to turn it on the right side but this trait is very annoying to say the least. A friend of mine gave me a clue: wing not balanced wingtip to wingtip. Once at home, I laboriously checked that and I found the left wingtip (the one with the launching pin) was in fact heavier. I now have a few grams lead weight under this wingtip and the whole wing balance perfectly, sitted on a 7/32 rod! I did not have time to launch again the QF-2, but as soon as I can I`ll keep you informed.
Note: my friend (as much a rookie at discus launching as I am) discus launched my QF-2 for me and got the same result: inverted flying at 20 to 25 foot high!

Sky Sharkster

Hi JB,
If you can get a lighter battery and re-cover the wing, the weight savings will surely be worth it.
But I forsee a problem; A lighter battery may not give you the correct C.G. And if you have to add ballast to correct it, you've gained nothing.
Again, mine isn't finished, either. I may well run into the same thing. But if yours does turn out tail-heavy after the modifications, the lighter boom might help. Yes, it's only a few grams, but they're all behind the C.G.
As for the launch height, practice should improve the height (at any weight) and a launch "setting" might help, also. This is typically a bit of down elevator (one click or so) and a small amount of turn away from the launch peg. Your weight in the other wing might eliminate the rudder correction, but the looping (almost) tendency is caused by the higher airspeed of the launch. In other words, the glide trim (of the elevator) is too high for the launch. This is very common on powered gliders, the usual correction is down elevator and some right trim (to compensate for torque reaction) linked to the throttle.
For DLG, the "Launch" setting is normally linked to a toggle switch, one you can reach with your thumb easily. One postion is the launch trim and the other is glide trim. Some flyers like to use the index finger, so pushing "up" towards your body is better. For a thumb-activated switch, I like to push "Down" away from my body.
Anyway, good luck!
Ron

jb48

Here iare a few pictures of my QF-2

jb48

Thanks Ron. I`ll reconsider what you said about the arrow tube slight weight saving behind the cg. I also wonder if lightening holes in tail surfaces would be a good move?
Next time I test fly my QF-2, I`ll try a little bit downtrim instead of the small uptrim I had on my first test (!)... my inverted flying problem maybe came from there. I`ll keep you informed of any development.

Sky Sharkster

Hi JB,
Great build on the QFII! I hope mine comes out that well.
The lighter boom might help, but I'd be reluctant to cut holes in the tail surfaces at this point. The problem is, then you'll have to re-cover them, offsetting any weight savings.
About the only other option (if it's severely tail-heavy) would be a new set of tail surfaces, maybe built up "sticks". But I notice virtually none of the DLGs use this method, it may not be strong enough for the launch stresses.
Ron

Sky Sharkster

Here's some details of the wingtips; On a DLG, this is an important step, since the launching peg is mounted into the tip.
(1) First, test-fit the tip between the upper and lower spars. Mine didn't fit (this was covered in the instructions) so I opened up the slot by using folded-over sandpaper.
(2) Once it's a press fit, the tip is glued in place. It should be even (flat) with the trailing edge.
(3) Close up of the finished joint.
Next, some reinforcement pieces will be glued in place. But I'm going to a Holiday barbeque!
Ron

Sky Sharkster

Hello Everyone,
Sorry it's been such a long stretch between posts, but I had to work two 60 hour-weeks (six 10-hour shifts!) this month. It was a new training period, hopefully it's over now.
Anyway, I dusted off the wing and added the tips, tip reinforcements and C/F ribbon to the top surface. Here's the photos;
(1) Measure the tip spar doublers.
(2) Cut to rough size.
(3) 4 Each, long and short ones.
(4) Glue in place, added 3/32" balsa trailing edge gusset. This was not called for on the plans, but seemed like a good idea.
(5) Right tip, top surface, glued and rough-sanded to shape.
(6) Right tip, bottom " ")
(7) Begin adding C/F ribbon with CA and plastic wrap to protect my finger. Need a fan and ventilation here!
(8) Top surface done.

Sky Sharkster

Again it's been a while since my last post, but finally got some time away from work and household duties.
Here's the wing mounting process. (2) 4:40 nylon bolts hold the wing in place. One of the fuselage plates with blind nut installed, the front one, was installed during the fuselage build, the other (rear plate) left off til now, per the instructions.
First I roughly aligned the wing in place and clamped it down.
Using a 3/32" bit, I drilled from the bottom up through the blind nut, into the wing, there's a laminated center block to accept the bolt. When the bit came through this to the top of the wing, I removed the drill bit and tried the bolt; Perfect!
But it's been my experience that a screwdriver slipping off a nylon bolt usually leaves gouges in balsa, right around the bolt hole. So I cut a small rectangle of 1/32" ply, rounded the edges and glued it over the hole, pressing it down to conform to the dihedral angle until it was dry. Then I re-drilled the hole through the ply.
Next I mounted the front bolt securely and "C" clamped the rear of the wing, per instructions.
Then I used the old "Thread tied to the rudder" trick to align the wing. I taped a length of thread to the rudder top and stretched it to one wingtip. Made a knot where it met the tip/T.E. joint. Swung the thread over to the other tip, found it was off a bit. Adjusted the wing alignment, tried again. After a couple of tries I had the wing exactly 90 degrees to the fuselage.
Now I can drill from the top down into the mounting plate (it's in place but not glued), remove the wing, take the plate out, glue the blind nut to the bottom of the plate and glue the plate into the fuselage.
Here's a few photos to help visualize all this;
Ron

Sky Sharkster

Here's the wing, finished and covered. I used transparent green and opaque white (top only, bottom is solid Trans green). Finished weight, without launching peg, 3.3 ounces, 94 grams.
Ron

Sky Sharkster

This is the start of the control system. First I cleared the pushrod guide tube holes with a 5/64 bit held in a pin vise. This is the same O.D. as the tubes, which are supplied with the kit.
Next I painted the bottom of the servo area with a thin coat of epoxy. I won't be using a servo tray, instead I'll use double-sided tape. This stuff holds great to smooth surfaces (like servo cases) but not too well to bare wood. So, a coat of expoxy for max grip.
Last, a double layer of masking tape around the HS 55's.
When the epoxy hardens, I'll dry-fit the servos, arms and make the "Z" bends in the pushrods. After a test of the control throws, the servos will stuck down with servo tape.
Ron.

Murocflyer

Looking good Ron!

I can't wait to see how she flies. How is the build experience overall? Fun or frustrating?

Frank

Sky Sharkster

Hi Frank,
Thanks for the kind words. The build has been fun, no major frustrations. Some of the changes I've made have been more of a personal choice, not because there was anything lacking in the kit. I do believe the instructions assume a higher level of experience than other M/M kits, it would be difficult (but not impossible) for a new builder.
The main problem has been a lack of time. I got very busy at work and lost a couple of months of "Hobby" time.
hope I get to fly this soon, we just got our first snowfall!
But I'm in the final stages, nearly done. Good thing, too. Just got a new kit, my next build thread. A (shhhh...) secret project!
Ron

Sky Sharkster

Here's a bit more on the control system. First I put the double-sided (Servo) tape on the servos, but didn't take peel the film off the other side, this is a "dry" run. So, in other words, the tape is stuck to the servos but the film prevents it from sticking to the fuselage bottom, until I'm ready.
I did this so I could see the exact height of the servo arm and vertical placement of the pushrod. Even a 1/16" off could cause a bind or poor alignment.
Then I made the "Z" bends in both pushrods, hooked them into servo arms and (after centering the servos) attached the servo arms to the servos.
Now I can see the line the pushrods take when the controls are activated.
It also helps to see where the Rx lead wires need to go to stay out of the way of moving parts.
Last, I cut the outer pushrod tubes to length and taped them to the boom. I'm going to run them outside, it just seems to work out better that way. Plus, I won't have to cut slots into the boom for exits.
Here's the photos, pretty tight fit!
Ron

Sky Sharkster

After setting the throws, I peeled the backing sheet from the servo tape and stuck' em down. The "Z" bends at the tail were next, then I put thread around the pushrod tubes at 3 locations. I checked the throws, about 1" right + left, 1/2" up + down. I had to reduce the elevator movement with the radio, initially there was too much throw.
Last thing, I weighed the fuselage with hatch, battery, wing bolts an Rx.
4.1 ounces, 115 grams. Combined with the wing;
3.3 ounces, 94 grams
-----------------
7.4 ounces, 209 grams
Ron

Sky Sharkster

The last couple of items on the build; Mounting the Rx + antenna, and the launching peg.
I used velcro to attach the Rx to the fuselage. First I routed the antenna, using small-diameter heat-shrink through the bulkheads and (Taped) over the servos. Then I drilled a hole next to the boom exit and taped the antenna to the bottom of the boom.
Then I roughed-up the middle of the peg and drilled out the right wingtip; I'm left-handed. Glued the peg in place by dripping a couple of drops of fast CA into the hole, with peg in place.
Also a photo of my very messy bench!
Ron

Sky Sharkster

After looking at the balsa nose, it occured to me the model wasn't really finished. So, a quick sweep of the benchtop and out with the iron.
Now it's done!
RTF, but wouldn't you know it, snow last yesterday and cold, windy today. Oh, well.
Ron

Sky Sharkster

I ran into a minor snag while aligning the hatch. The instructions suggest a tongue at the front and tape at the rear. This type hold-down has worked for me many times (sometimes using a small screw at the rear), but the small compartment is so tight, the battery touches the top, leaving no room for the tongue.
So, inlay the tongue.
Here's the photos, it should be self-explanatory;
Ron

Murocflyer

Nice job Ron! Looked like you enjoyed building it. Please let us know how she flies. I enjoyed my DLG but she doesn't get much flight time anymore.

Frank

smokejohnson

Did you ever get a chance to fly this one? Do you have any more pics?

Sky Sharkster

Hi James + Frank,
Thanks for the interest, no flights yet, not even a test glide. The firsr real snowstorm of the year came this week, and even after it stopped the wind's been blowing pretty hard. By Sunday it's supposed to be 20 degrees and another storm. May be a while, but I'll keep you posted when I get a chance to fly!
Ron

buzzbomber

Didja get to fly the QF2 yet? I just pulled my kit out of the bag and started reading the manual last night. Unfortunately, I'm in the middle of building a Cub wing, a patio and retaining wall project, and a bathroom renovation, so it might take a while...

Sky Sharkster

Hi Buzzbomber, sounds like you have your hands full!
I haven't flown the glider yet, after it finally stopped snowing, it's been windy and/or raining nearly every weekend. I'll get it going soon and post photos here.
Thanks for the interest,
Ron