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Aug 07, 2019, 05:11 PM
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F3res plank in xflr5:

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Aug 08, 2019, 10:14 PM
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Thor F3 res plank


Thank you for the go ahead.
I've been designing for the last few day's, so continuing on, Thor's vertical tail was drawn with the pod and the full size root section on the drawing table. I considered many ways of designing the pod and what kept coming to mind was the beam method. The pod from nose to leading edge of wing is 10 inches. The pod is 7/8 inch wide.
I determined these beams to be 1/2 inch tall x 12 -1/2 inch long sheets . The possiblities are 1/16 ply wood or a laminations of 1/64 ply wood and 1/16 balsa. The 2 beams are conected by small bulk heads and a hollowed out nose block of hard balsa or soft bass wood or pine block. 2 -1/2 inches of the fuse pod end is a double sideded beam right side and a left side that are glued into slots in the wings sheeted leading edge but much later. Next is 1/2 inch balsa blocks added top and bottom , ((only tack glued at this point)). These 2 blocks are contour sanded for the side veiw contours using a template and then carfully rounded on top and bottom using templates as well. The top and bottom blocks are now removed and hollowed out on the inside to 1/8 to 3/16 thickness with calipers and gadges. A small dremel tool works well here, slowly removing material and measureing as you go. The pod's bottom block is then reglued on and the radio gear is fitted. Then the top block is marked for the radio gear access hatch and then glued on. final sanding will be needed and small touch up if required . The pod is then glassed on the outside and the hatch is cut free. Or a box shape can be made simply of light balsa or 1/16 sheet ply wood, instead of the above shape and rounded design.
The vertical fin is designed for carbon tube spar and carbon rod leading edge, balsa ribs and balsa trailing edge as well.
I will scan in these drawings soon and any ideas or input is welcome.
Kyle.
Aug 09, 2019, 07:52 AM
You know nothing....
Stuart A's Avatar
I’d be tempted to make both the balsa and pine nose blocks,to see which suits the balance best.
Look forward to your drawings.
Aug 09, 2019, 08:35 AM
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EdSoars's Avatar
Thread OP
Kyle, this is getting better and better. I build planks for flying over slopes and landing on rocks, so your structures are much less crash-proof than mine... and lighter!

Do you have a simple formula for calculating the vertical fin volume? Would it be similar to a conventional planform?

The European planks tend to have large, tall fins right behind the wing TE (the Amokka), but there are successful planks with long tail booms and small fins (the Artemis). Both of these are good DS planks.

Is one design better for thermal flying?
Aug 19, 2019, 11:55 PM
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Thor F3 res plank


I have only flown a zagii THL and that's what I have to go on and what I've seen here. I have read alot over the years on flying wings and just think alot about all these differant stratigies others have done already. I am willing to take chances by building the structures all day in my mind while I'm at work. I think of what if this happens? Or that and from RCSD issues I have something to go on. I think of all the frame work and landing aproaches that go wrong that I've seen over the 45 or so years of rc gliders. Both my own creations as well as flying with the club I really have seen almost every possible screw up at the field. I do a lot of analyzing. I just can't seem to spell very well.
I finaly completed a few peices the last couple of days. The side beams and a keel for the bottom of the pod. I am working on the 4 bulkheads that link the side beams together and then things will start to take shape from there.
Probably by this friday I'll glue stuff up and you should know I've been taking photo's along the way. My goal is by Friday to have the drawings and photo's up loaded here or sooner. I've never built a keel pod rounded fuse before.
I draw it up in my mind thinking of the top veiw, bottom, side, cross section and test things physicaly over and over until I'm saticfied I've slightly over engineered it to not break under normal flying plus a little bit more.
I am not a computer guy so that should answer your question. I just really enjoy engineering and flying.
Kyle.
Aug 21, 2019, 07:51 AM
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EdSoars's Avatar
Thread OP
Kyle, as long as your readers can figure out what you mean, spelling doesn't matter much. And if you, like I, used a slide-rule in college, then you ARE a computer guy. Just because they had bamboo on the inside and not printed circuits doesn't mean a slip-stick isn't a computer.

Looking forward to the photos and drawings.

I have am looking for a very-easy-to-learn CAD program for my design work. 2D would work. I've been using MicroGraphix Designer 7 for over 15 years and it's getting hard to get it operating on new computers.

Any recommendations out there?
Aug 21, 2019, 05:34 PM
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2 meter, built up balsa, plank, for F3 res competion. Using the PW106 airfoil.


My friend told me about a few, (Design Sparks ) I think that's what's it called and also E machine shop. If you google the top 10 easiest or best CAD programs there will be a list. I have used E machine shop and also YouTube video's show you how to, from the very beginning. I am just being pulled in too many area's at the moment to really implement it.
Last night I got an email from Peter W and he told me about a few mod's that would improve the design so I am going to do that.
Increase the span of the elevon's to 75% of span = 29 inch elevon's.
Relocate the spoiler to 50% of cord
Optional airfoil using the PW BRETT RES he developed for this type of model.
CG at 5.5 centimeter's to 6 from the leading edge. Requiring more nose weight or a longer nose over all or both.
All this input from Peter is wonderful because you go from a hand drawn sketch to some thing firming up, to implementation of actual data that makes changes that you have to go with. This means I learn some thing which is wonderful indeed! Yes I am smiling.
By increasing the elevon's to 29 inches this makes a situation occur that I was not looking forward to. If I want the spoiler to be in the middle of the wing and one piece then this makes the wing totally flat. He suggested They start sooner inboard and this means there is ether a very short center section that stops at the spoiler (12 inches) and then the dihedral starts there or no dihedral and I could raise the wing tips, the last 3 1/2 inches if I desire. I would only raise the wing tips for better thermaling. The Zagii THL I flew was flat also so not a big deal there. Also in the video I watched on the sample plank over in Germany, it's also flat and thermals just fine. It's a beautiful micro DLG you should see it.
Last night I decided to go with the AAA 4 cell packs that I already have and they weigh 2 ounces roughly (950 mAh) and this sets in stone where the bulk heads go and this tells me the final weight goes up.
The increase in span of the elevon's means the servo's requirements need to be more so instead of 4.5 gram servo's I end up using 7.5 gram one's. I'm using gear in my shop and not buying if possible.
I truly love the working out of design challenges.
Kyle
Aug 23, 2019, 06:45 PM
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Thor F3 res plank


The Pod for my Thor res plank front half.
Kyle
Aug 23, 2019, 06:50 PM
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Thor F3 res plank


The Pod back half.
Kyle
Aug 23, 2019, 07:00 PM
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Thor F3 res plank


Thor's vertical fin, Balsa ribs, trailing edge. CF rod leading edge, CF tube spar. Boom is wood 1/32 sheet ply sides, Basswood spar on top and on bottom with balsa fill in the middle. This is a removable assembly or to be glued in to wing trailing edge, optional. The boom can also be CF tube.
Kyle
Aug 23, 2019, 07:07 PM
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Thor F3 res plank


The larger elevon's and slightly smaller spoilers.
Kyle
Aug 24, 2019, 07:58 AM
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EdSoars's Avatar
Thread OP
I'm be interested to see what effect that spoiler has on pitch. Did you design and locate it in a way that pitch inputs are minimal?

Is there a way to put the servo in the wing? it might be less prone to damage.

I am enjoying your hand-drafted drawings.

ed
Aug 24, 2019, 04:16 PM
Registered User

Thor F3 res plank


Peter W emailed me to put the spoiler at 50% cord for that very reason.
The spoiler servo is next to the reciever and it can be relocated in the wing, also not in stone yet.
I am enjoying the process. Thank you.
Kyle.
Aug 25, 2019, 05:43 PM
Registered User

Thor F3 res plank


Well it took alot of teaching from my wife and now I know how to load photo's from an old hand-me-down out dated smart phone to the lap top. Progress I do believe. I am a cave man and I am trying to get up to speed with the rest of humanity. Any way I have about 60 plus photo's to select from and I will start at the reasons why I desided to build the pod this way, all scupted and shaped nice and not just a box. I really like structual integrity and not just barely enough and it must be beautiful. So the 1/32 sheet ply and basswood beams were a way to do the desired finished pod but this would require an additional keel located on the bottom to add the nessesary strength for landings (2 layers of 1/16 basswood with 1/32 plywood in the middle). I knew I had to tie together the three load bearing members and this would require bulkheads but I was unhappy with the 1/16 ply wood for the strength and the juelers saw I like to use to cut things out. I don't like jaged edges after a cut. So I laminated 2 layers of 1/32 sheet plywood at 90 deg. to each other. I was happy and every thing came together just fine. I was able to get the strength required and at a very light 23 grams so far. I may be able to achieve my goal of a 1 ounce pod or come close to that target wieght.
Kyle
Aug 25, 2019, 06:26 PM
Registered User

Thor F3 res plank


There is a slight bevel cut on the top of the 2 beams that enable a beter rounding on the top of the pod.
The strangest part of the construction of the pod was the use of the extreme contest 1/4 thick balsa sheet and how it was used for all the rounded parts. Each part was cut to a length of about 1/32 inch longer, then fine sanded to fit really nice in its space between bulkheads, then fitted at the 45 degree angle, then cut 1/16 inch smaller than the beams and keel (to sink deep into the space) then faccet cut on the out side, ruff sanded, fine sanded, then hollowed out to the desired thickness internally and a final fit and then glued and cleaned up. All excess glue wiped away inside and out on each one, nice and neat.
I used a combination of a small diameter sanding tube in the dremel tool and a rounded tapered file. With the use of the digital calipers from the hardware store this became really easy. I was not looking forward to hollowing out all those parts. The long sections on the pod bottom are thinned down to 3.45mm. in the back only 2.25mm thicknes.
If I need to add nose wieght the nose block is hollowed out before being glued on to the pod.
all radio gear fit beter than expected.
Kyle


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