doxilia

My Feedback: (3)

Thanks Mitch.

Yea, I was considering a narrow (1" probably) strip of cloth and epoxy or simply CA. I don't think weight in this area will be an issue in either of our builds since you're using a 4 stroke and I might use a tuned pipe. I noticed that you placed your empennage servos in the rear. This will presumably help to offset the 4 stroke weight.

I'm not sure if you had in mind placing your battery above the landing gear under the tank but I would imagine that might be option if necessary. Somehow I suspect that yours might end up just aft of F2 for CG purposes and mine probably too. In any case, space is not an issue.

I don't recall but I believe Jim doesn't make a point about the stab junction. Between thick fuse sides, triangle stock and fillets I'm not too concerned about the strength of the stab junction once glued in place. I don't plan to install the bottom block until the stab is in place allowing the glue joint to be strengthened. One thing I did consider was to make an extension to the fin bottom so that it would notch into the top block but I ended up not doing it.

David.

jmb52760

David,

Check my thread and you'll see how I used the microglas. I put it only in the area of the empennage interface. You don't even need to make it smooth that way, just scuff it up so it'll stick.

I've been trying to decide if I want to notch the vertical to the top block as well. I haven't built a plane in a long time that just called for a simple butt joint here. I guess on the original design a glass layer may have added strength. It is a fairly wide interface.

Mitch

jmb52760

Oh, on CA: I avoid using CA on foam wings/stabs. If any of it gets thru the balsa it will eat the foam. (unless you are using foam-safe, I suppose)

doxilia

My Feedback: (3)

Of course - good point Mitch.

I actually have been using foam safe on the wing prep build. It's funny stuff. I hadn't used it before. It indeed doesn't smell nor fume but aside from that it isn't quite like regular CA either. The catalytic moisture effect is much slower which actually is helpful in positioning the sheeting pieces and holding them until they dry.

Re the fin, yes, I believe that Jim never considered using film on the plane - he always glassed the whole thing and then painted so a notch was probably not a high design priority.

David.

doxilia

My Feedback: (3)

A little more progress today...

Stab is ready for elevators (need some 3/8" sheet balsa) to be cut and sanded followed by stab tips which are ready to be glued and sanded.

Wing prep is finally complete. Servo wells, lead tunnels and retract linkage tunnels done. Given the small dimension of the wing, routing the pushrods in the wheel bays was impractical. There was also not enough of an angle to allow the rods to route away from the center of the wheel in order to clear the axle and collar. After staring and thinking of how to do this 100 different ways, I finally concluded to route the rods through the wing and over the top of the bays toward the center mounted servo. In manual tests it appears to work well.

Because the wing has had foam removed in the wheel area on the top and bottom, I've decided to reinforce it prior to sheeting using carbon tape. I'll run one strand along the bottom CG line between the aileron servo bays (ie below the servo lead tunnels) and another along the top between the servo lead tunnels and the gear pushrod tunnels. These strips will effectively act as spars.

Wing sheeting, LE, TE, and tips are ready for final assembly. In order to save a few $ on the wing/stab tips, rather than buying thick blocks, I bought two thinner balsa sticks - 1" x 1/2" (soft) and 1" x 3/4" (medium). The latter was used as is for the stab tips. For the wing tips I cut laminated the 1/2" and 3/4" sticks to form a 1" x 1-1/4" block and then cut the tips from this. The soft inner balsa will allow me to hollow the tip insides more easily while the harder outer block provides some resistance to knocks.

I'm looking forward to finished wing panels!

David.

doxilia

My Feedback: (3)

On the fuse side,

final cutting and shaping of formers has been finished. 4 oz tank fits nicely with about 1/8" on either side of it for some foam padding. Space below tank floor provides room for a 1-3/4" nose wheel if desired but I'll use a 1-1/2" Lectra Lite to provide more space for the nose gear servo. I hope to be able to Y-connect the retract servos to channel 5 (will depend on required travel for each) leaving me with two channels for aileron servos. Still waiting for the engine mounts and the nose gear in order to install onto FW.

Quick trial assembly of fuse to check parts fit and alignment. I discovered that one of my two fuse upper 1/2" triangle stock was actually 9/16" . Back to the LHS for elevators and triangle stock.

David.

alcarafa

Great job David it's coming up nice, what retract servo are you using on wings ? I bought same manual retracts you order for your plane, think std retrac servos are 2 big for this babys.

Carbon fiber acting as spars is a very good idea, will try it in mine.

Regards.
Rafa

doxilia

My Feedback: (3)

Hey Rafa,

thanks for your comments.

What retracts did you order? Are these for the Magic 20?

Standard servo's are definitely too big for these birds, especially the 15 sized. For the 30 sized, they can be considered but there are good, inexpensive digital servo's out there with some torque for those birds. I like the Hobbico digital TS-30 and 35's shown in my Nanorare thread.

For mains retracts a low profile standard aileron servo is possible but not necessary - the gear is very light. I'll be using a Hitec HS-65 for the mains and HS-55 for the nose. I'll also use HS-65's on the ailerons and empennage and another HS-55 on throttle for a total of 5 HS-65's and 2 HS-55's. I'll also probably use a 400 mAh NiMH sub AAA pack - very light.

I'm feeling optimistic about weight today!

David.

alcarafa

Daid I ordered the Hbbico 10 size mains for the Magic , if this are not strong enough then I'll switch to build a deception 10 with magnum 15 xls first.
and use Hex 9 grm sevos .

( http://www.hobbycity.com/hobbycity/s...ec_Micro_Servo )

Are excellent ones and center better than hitec and futaba micros, also very strong gears compared to hitec or futaba wich are very weak and price is 3.65 dlls each.

You think I can use this ones for retracts ? strong torque 1.6 kg.

Batteries I make my own packs , last one for the TIPO was made with AAA NiM 2000 mah [X(] yes they last long.

doxilia

My Feedback: (3)

Rafa,

the Hobbico 10 sized mains are nice. They use 3/32" struts so are intended for 10-15 sized models including 1/2A. For the 20-30 sized models we want 1/8" struts and a stronger retract body much like the Robart's, MK's and Spring-Air 600's discussed above.

I have no experience with those servo's but they sound good. Anything with the torque equivalent of an HS-65 should be fine on the Hobbico 10's.

Since you already have a Picorare (Tipo 15), the Magic 20 sounds like a nice project. I wouldn't let some retracts or servo's affect your building plans! I'm basically building the D15 as building practice with foam wings and mechanical retract installation. A larger model would have been easier though. I'd venture the cost difference between a 15 and 30 size model is about 20%.

Having said that, the D15 is a fun model to build. Simple design, clean lines and straight forward build. I was actually hoping to find a Webra .12 RE engine for it which were designed for ducted fans. I could have put a pipe on it running under the canopy! I'm not sure that I'll use a pipe on it now though as I have complete ST G20's with muffler and a K&B 18 with muffler.

We'll see.

David.

doxilia

My Feedback: (3)

A few images should tell the story.

Carbon tape applied to top and bottom. Laminated wing cores drying overnight. Resin smoothed out with alcohol applied to the retract pushrod foam tunnels to seal and provide a running surface for the rods. I might add outer shafts to the rods to keep the spacing snug but probably not needed.

I think I have about 100 lbs on it - perphaps a tad too much

David.

rv7driver

My Feedback: (105)

David, that wing is really looking nice! still waiting on mine to show up sure does take a long time from Canada to the US. by the way I'm back from Singapore, will get your stuff togeather and let you know when they are ready for shipment. Pete

rainedave

My Feedback: (1)

David, I might have missed it in an earlier thread, but what adhesive did you use for your wing skins?

Looking great.

David

doxilia

My Feedback: (3)

Gents,

thanks for the continued interest. I'm eager to get this one framed up so I can focus solely on the GP Tipo's. I'm finding I have to pretty much cut/assemble all the wood pieces from scratch (that's what its about though, right? [:-]) as even the aileron stock I picked up won't work. I didn't quite have all the dimensions with me when I bought most of the wood (not the sharpest pencil in the room... ) so I winged some of it thinking it would work. A simple sheet of 3/8" balsa should do nicely for the ailerons and elevators after some good old shaping.

BTW, I don't have any power tools other than an $8 Dremel knock off which is off balance so I tend not to use it (my birthday is coming up though so perhaps the family will kindly donate an XPR 400 kit... ). I do all cutting/shaping with a small saw, a #11 and some nice, recently acquired sanding blocks. Of course sometimes it shows, but that's ok. Maybe Santa will listen to my wish for a jig saw next xmas...

Pete,

welcome back! How was the flight? Your usual aluminum tube displacement?

Wow! I would have imagined the cores would be there by now. Could be holidays and all. Let's check that tracking number to see where they're at (I have to find it):

http://www.canadapost.ca/Personal/To...temSingle.aspx

Looking forward to those Singapore goodies. BTW, did you pick up any fuel tanks?

David.

doxilia

My Feedback: (3)

David,

I've used a mix of foam safe medium CA for the 1/16" balsa lining (wells) and 5 (stabs) or 30 (wings) min epoxy for attaching LE, TE and tips (well eventually). For laminating the CF strands and for attaching the sheeting I'm using straight Pacer Z-poxy laminating resin - very nice stuff. First time I use Pacer. I guess the price is not just for the brand ($15 for 12 oz up in this neck of the woods). To build the sheeting from 1/16" stock I used GP aliphatic resin.

The CF tape is actually not tape but what I believe is referred to as CF mat - a series of hair thick strands. First time I use this stuff too (The pack is actually about 20 years old [8D]). When applying you have to be careful not to let the ends loose from masking tape and the backing or else it can wind up in a serious mess fast. So you have to apply tape and then cut at the mid point of the tape so both ends always have tape on them. I believe today there are perhaps better alternatives like straight flat CF sections that can be glued on easily and then wet with resin to solidify. However, the tape takes the worry out of warping until you lay up your core sandwich.

I applied laminating resin to the core with a brush locally, then I took my CF strands taped at each end and removed the root end tape while holding the CF very close to the end. Then press down into the resin at the root. Once the CF is wet, it doesn't bunch up. Then with a finger I laid down the remainder toward the tip removing the tape at the very end once it was all wet. I then smoothed it out as much as possible with a finger dipped into alcohol pulling excess epoxy off the tape into a paper towel.

Although it does add perhaps 1 mm of thickness to the core, I hope the deformation of the airfoil won't be something that will be registered by the sheeting. In retrospect, I could have used far less CF - I think a simple 1/4" wide strand in 3 or 4 places along the span would do the trick. I might have added 1/8 oz too much with the amount of CF I used - it's very light stuff. I suspect the cores will be hard as a rock by tomorrow morning...

In applying the laminating resin to sheet the stabs and wings, I paint the epoxy onto the sheeting only using a brush (no need to apply to the cores too like with contact cement. The cores tend to make epoxy disappear fast!) A roller can be used too for larger sheet surfaces but they can also soak up a great deal of glue. Once the entire sheet has been brushed I take a Bondo scraper (I think there's some Teflon in there) and pass it over the sheets. This spreads out the glue nicely and pools up considerable amounts of glue. I actually end up removing about half of the applied epoxy leaving the sheets with a wet sheen to them. One sheet at a time as you proceed building your sandwich.

For reference, I mixed two batches of 1/2 oz of resin for each wing panel (two sheets). The first sheet takes up about 3/4 of the resin brushed on but returns about 1/4 ounce scraped back into the container. In short, the resin used to laminate a 40" wing is about 1 oz (a tad less actually).

I weighed my CF prepped cores just before sheeting to 42g each (<1.5 oz). The steel retract pushrods and clevises are put in place prior to laying down the top sheets. We'll see how much the no contest skins adds to the cores but I'm feeling confident that I can probably come in with a finished wing at about 8 oz leaving me with another 8 oz or so for the fuse and empennage. My goal is a 16-18 oz airframe unfinished with no gear.

That was a tad long.

David.

rv7driver

My Feedback: (105)

David, thanks glad to be home, got in New years eve, had several cold beverages and was out for 12 hours never saw Newyears. I did check, looks like the wings are close by: maybe tomorrow or Monday. The Holidays did slow things down. I did buy a couple of 190cc tanks and had Ron order me 4 150cc tanks they were out of them. will pick them up next trip. I sent the only one I had to zubba.

Keep up the great work on the D10 its really looking good. do you want one of the 190cc tanks???????

Pete

doxilia

My Feedback: (3)

Pete,

Oh yes... both on the tank and the cold beverages. In fact, I might just pour the beverage into the tank and sip it so [8D]! If you're willing to part with one of the 190's it would make a nice tank for another 20 build (too many lined up so I won't mention which).

I've been out a tad with a flu of some sort - sore muscles and blurry vision from headaches. So no beverages recently for me. New Years came in with lemonade as we watched the apple fall in bed. That's life with small kids for you [sm=drowning.gif]. Gotta love the little buggers though. On the plus side, attempting to build with blurry vision and a head ache takes your mind off the details.

Thanks for the nice comments on the D10. Soon I'll be out of the foam world and back to wood - a friendlier element.

I just checked on your cores. They apparently were out for delivery on the 27th. You must have received notice from USPS if they attempted delivery. Otherwise they should be there any day now. I'm hoping they treated them nicely!

David.

zubba

Pete,
If you need that 150cc tank back let me know i can return it asap, i can wait till they get some more in.
I ended up getting a 190cc tank in the c20, also i have a few 190cc tanks if you guys need one.

-Jason

rv7driver

My Feedback: (105)

Jason, thanks but I'm good on the 150cc will pick up 4 of them when I go back to singapore, had Ron order them last trip will not start the Cosmos 20 for a while. Got any pic's of the 190cc in your C20?? David by the way the wings are at the post office my wife was not @ home when they tried to deliver them on the 27th will pick up Monday, thanks again.

Pete

zubba

Few pics its tight as it gets in there i still have to do a little more sanding on the fuse sides and smooth sand the rails.
-Jason

doxilia

My Feedback: (3)

Pete,

glad to hear.

Progress...? [8D][sm=tongue_smile.gif]

P.S. This may seem a little obsessive but I'll do it anyways:

Left Core Prepped CF = 42g
Right Core Prepped CF = 42g

Left Panel Sheeted (w/ gear rod) = 91g
Right Panel Sheeted (w/ gear rod) = 89g

Left Panel w/ LE&TE = 99g (3.5 oz)
Right Panel w/ LE&TE = 94g (3.3 oz)

Total cut LE/TE weight before application = 25g
Total Wing Tips before attaching and sanding = 20g

Total Wing Weight wo/ ailerons & tips = 193g (6.8 oz)

Total Finished Wing Weight w/ ailerons & tips = 225g (< 8 oz) - expected.

Response of builder? [sm=shades_smile.gif]

'nough said.

David.

rainedave

My Feedback: (1)

Straighten up your bench before you lose something in all that clutter!

Absolutely beautiful work!

David

doxilia

My Feedback: (3)

Bottom work...

Wells begin 90 mm in and run for 112 mm. First cut... very slooowwwwly...

Servo wells centered at 235mm along CG line just forward of front gear plate. Make littlest hole possible - hollow - good, we're in.

Ailerons & elevators, here we come!

Tack glue, sand to contour, mark aileron line. Next, tack glue tips, sand to contour and pop off. Hollow tips, glue permanently.

Pop off TE, cut ailerons, glue center TE portions, hinge ailerons. Bevel ailerons. Wing done! Follow suit with stab.

We're almost there.

David.

doxilia

My Feedback: (3)

... he, he...

I actually loose stuff all the time - don't ask why.

I suppose habits force fed by one's grandmother at age 7 has a lasting effect: "clean up before you present!"

'night gents.

David.

doxilia

My Feedback: (3)

Before I tuck in and forget, I should mention:

I cut the retract rod wells in the wing as two opposing triangles with a common side along the LG axis. When retracted, the pushrods on either side line up along the LG axis with the rod connectors at 90 deg to the servo axis and in line with each other. When the LG is extended, the pushrods rotate and the connectors line up with the servo axis causing the rods to move diagonally along the wing chord - forward for one panel, rearward for the other. The rod openings in the gear servo bay show this assymetry (see photos above).

Now, we just have to hope it works as crudely tested... we'll need a joined wing first.

David.