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Old 11-11-2018, 10:28 AM
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That's the cool thing about multiple axis foam cutters -- those of us with access get what we want and like eventually.

Controlling separation from root to tip is an interesting topic for me and the foam cutters gives us the ability to experiment with angles, laminar, and profile shapes relative to the spar line.

Energizing and de-energizing air molecules at various points along the wing from root to tip is something worth experimenting with because we're dealing with smaller structures relative to the same air density as full scale.

Here are two 8035 14% on top with the 30% laminar at the root with a 25% lam at the tip. I only decreased the leading edge sweep in the second image from 18% to 12.5%.

The 3rd image is the 63 with the same thickness with the tip LE forward to 10%.

I did it the first time only because I really enjoy an Edge 540 for 3D and just wanted to see what happens if I create a wing with some Edge characteristics, but reduced the drag and moving separation at the root while keeping the pressure distribution the same at the tip. Of course, tip stability is very subjective.
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Old 11-11-2018, 02:50 PM
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Originally Posted by Aeroplayin View Post
That's the cool thing about multiple axis foam cutters -- those of us with access get what we want and like eventually.

Controlling separation from root to tip is an interesting topic for me and the foam cutters gives us the ability to experiment with angles, laminar, and profile shapes relative to the spar line.

Energizing and de-energizing air molecules at various points along the wing from root to tip is something worth experimenting with because we're dealing with smaller structures relative to the same air density as full scale.

Here are two 8035 14% on top with the 30% laminar at the root with a 25% lam at the tip. I only decreased the leading edge sweep in the second image from 18% to 12.5%.

The 3rd image is the 63 with the same thickness with the tip LE forward to 10%.

I did it the first time only because I really enjoy an Edge 540 for 3D and just wanted to see what happens if I create a wing with some Edge characteristics, but reduced the drag and moving separation at the root while keeping the pressure distribution the same at the tip. Of course, tip stability is very subjective.

OK I see that you are playing around with the high point position. I have never done that, only thickness and also thicken the TE.
Presumably you are using Profili Pro for this? Have you looked at the CL/Alpha data with these modifications? A bit time consuming as there are so many options to compare. My profili dongle is intermittent, so I can only have short sessions before it crashes again. However I got a comparison between the NACA and Selig foils. Interestingly this graph seems to show a sharper stall for the NACA foil. However I am going to stay with S8035 for now. For the moment I can get much more improvement to my snaps with practice rather than aerodynamics
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Old 11-11-2018, 03:21 PM
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Presumably you are using Profili Pro for this? Have you looked at the CL/Alpha data with these modifications?
No to both. I hit a really nice groove when I did the 63 at the root with a 36% lam and the S8035 with a 25% lam at the tip with a shallow LE sweep with the forward 1/4-cord sweep. I've been playing with the angles ever since and subtle changes don't seem to do that much for what I'm looking for.

I've increased the aileron area and increased the servo torque to initiate snaps and rolls better, and stabilized the wing to stop the snap and roll immediately. It took a while, but I think I'm where I want to be now. But it's all subjective so some may not like it at all.

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For the moment I can get much more improvement to my snaps with practice rather than aerodynamics
I agree and once I feel comfortable with a wing's performance, it's all about getting off the drawing board and spending time with it in the air. I find that getting better with the same plane changes my mind about the performance envelop, so I'd rather fly the plane for a season before making any new decisions about the design. We'll have some great flying weather from now until the end of June again.
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Old 11-12-2018, 04:20 PM
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Mostly finished the drawing. Did my first 3D sketch for the tail wheel leg. The wings and stabilisers get done in the foam cutting software (GMFC) so I only need the outlines in this drawing. I usually edit the profiles for the decks in Autocad but I will try to do it in Fusion this time. I will start extracting the drawings for the ply parts. I'm just going to glue stick the drawings to the ply and cut them out with the band saw and fret saw.
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Old 11-12-2018, 05:00 PM
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That looks great. Are you going to make the canopy yourself?
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Old 11-12-2018, 05:58 PM
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[QUOTE=Aeroplayin;2774916]That looks great. Are you going to make the canopy yourself?[/QUOTE
I'm not set up for large vac forming. I will make the plug. I will get Mike Briggs of PBG fame to do it for me.
Had to get a new sheet of 3.8mm Birch ply.
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Old 11-13-2018, 04:46 PM
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Pretty much finished the drawing. Anything else I will do as I build. Doing the drawing has been a good learning curve. Next time I would do all the parts as components not bodies. This would mean I would have to get better at joints.
I'm now working on getting the parts onto paper.
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Old 11-14-2018, 01:05 AM
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Ugh.. great work! I'm still stuck trying to figure out how to exactly scale/match my top/side/front view drawings
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Old 11-16-2018, 05:29 PM
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Started printing out the parts but there were a few things I wasn't happy about. Like the lack of access to the front wing retaining nuts, also couldn't get the side/down thrust right. So I have started from scratch again. I was able to simplify the basic shape of the fuselage. Also have a nice clean drawing with no error messages. I have the basics worked out now so it has gone ahead quite quickly.
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Old 11-17-2018, 09:29 AM
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I'm not set up for large vac forming. I will make the plug. I will get Mike Briggs of PBG fame to do it for me.
Had to get a new sheet of 3.8mm Birch ply.
I used birch for the beams and firewall, but went with Aspen ply for the rest of the plane. Was thinking about poplar to get it really light since all but two formers were 6.33 mm, but stayed with Aspen. I was still able to bring the 102" plane in at 25.54 lbs with the heavy electric setup and high capacity main pack, and the ply density had a lot to do with it. I also went with 7mm stringers and longerons.

Tony Tan from Pilot was nice enough to send me the carbon tubes and sleeves I needed, plus the carbon undercarriage. I also went with the J&J titanium tailwheel which seemed scale. But I eventually went to a 51g tailwheel so the expensive J&J is still sitting in one of my parts draw with no less than a dozen other tailwheels I never used or are good enough to recycle.

I also went with Kavan 5" main wheels. They are only 142g for the two, and although I was concerned about durability, they actually hold up really well on our turf runway. I went ahead and bought two more sets since I want to put another one of these planes together this season.

The final strength test for me was to test the modulus for the wings, as in the images I posted, but to also have my buddy hold the wing tube down while I twisted the stab tube, looking for any significant flex in the fuse. The wing held my weight and there was no noticeable flex in the fuse that either of us could see.

The other places I dropped weight was in the fiberglass and PETG. I was able to do that since the plane was purpose built for electric, and would go with thicker PETG for the canopy if I decided to go gas with the next one. No wheel pants or spats, titanium axles, and that brought the 35% scale plane in at 14.19 pounds standing on the wheels with no power and control components.

I'd still like to think there's the right radial out there for me.
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Old 11-17-2018, 10:19 AM
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You 2 are absolutely nuts (in a good way)... I understand about 3% of what yall are talking about. lol

-Craig
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Old 11-17-2018, 11:58 AM
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You 2 are absolutely nuts (in a good way)... I understand about 3% of what yall are talking about. lol

-Craig
You don't know nuts....

Nuts is deciding you don't like the gap between the spinner back plate and the cowl on your custom-built plane with a radial front, then design and build a shroud to eliminate it. That's crazy.

I eventually painted both white, but you get the idea.

Then a builder I know from overseas, who is equally as nuts, said he could weave Kevlar and carbon into spinner cone to fit my shroud, and I said, "ok, let's see it". And so he did. Sickness, for sure.
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Old 11-17-2018, 06:43 PM
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Haha, wow... that’s nutty on a new level. But pretty freakin cool too
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Old 11-18-2018, 06:52 PM
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Still working away at the drawings.Not far off now. I'm much happier with this. I've hidden the right side for clarity. When it is done I will start on the lightening holes.
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Old 11-19-2018, 11:37 PM
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More work on the motor box/internal structure. Quite time consuming but it is nearly done.
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