Building the SoarKraft Roughgen V2

[Wayne]

It's on this page:

Carbon Fiber Strips One Meter Lengths

Available is a variety of sizes and 1 meter in length.

alofthobbies.com

1mm X 4mm x 1000mm

Yes, have used the foaming stuff and am not a fan. Here is a video for reference:

Lighter? Yes. Weaker? Yes. Kind of a pain to print too. Thought I had bought some of the new Polymaker stuff, but I got the wrong one. That stuff sounds much better.

The orange filament in the plane above is a standard PLA from 3Dsolutech (or something like that) and is kind of rubbery. I like it a fair amount. The clear is from the same company but is like a normal PLA. This is one of those fun things, even the same filament from the same company but in different colors can have different properties.

 

[waynesie]

Here is the follow up to the Polymaker LW-PLA stuff. Turned out well.... easy to loose 200g or 1/3 the weight just by changing the print spool.
The flying starts at 10 min in if the details are too boring.

 

[Wayne]

I have a idea for you if you would like an even lighter wing.. Would require changing out the carbon used in the wing. A single 2mm thick carbon strip would be plenty for a single spar for a lighter version of the plane. We have a 2mmx10mm, but could check to see if we could get something like a 2mmx5mm. That should be very strong with a good weight savings. Just a thought.. Can send you a stick of the 2x10 to play with if you like.

Forgot to mention that I finished the plane Friday at our build night. All went smooth except my CA spill ito the EZ connector threads on the elevator. Oh yeah and my total lack of the correct battery. I made up a square AA pack and then found out that would not fit, and we don’t have any AAA cells anymore. So setup a small 2S limo and small UBEC we had sitting around, but the UBEC was not happy and would brown out. After much playing around trying to get that to work, I suddenly noticed a 4 cell NiHM pack we use for testing and it fit. Done! 2/3AA cells I think in a flat pack. Will need a little nose weight for CG.

 

[ORRich]

Hey everyone,
Im new to the Aloft forum, but I designed this model. I am SoarKraft.

I have been flying and crashing RC planes since 1984... I was 12 when I crashed my first Sig Kadet. I've done helicopters, jets, aerobatic, 3D, pylon racing, and slope gliders... mostly gliders for the past 20 years with many a model destroyed learning to do Dynamic Soaring.... many. I have built balsa tissue models all the way to vacuum bagged carbon fiber layups, cutting molds, CNC foam cutter, etc. I have built / bought / crashed / repaired / crashed again so many planes over the years.... and had a great time doing it.

I have been 3D printing parts for plastic design, product design and designs for injection molding for 25+ years. I am a Mechanical Engineer specializing in product development.
3D printers have become inexpensive and much easier to use recently, I use them everyday,
but they are still not for everyday items...
No one is walking around in 3D printed shoes and a store bought $10 cell phone case is way better than anything you can 3D print.

However you can buy a 3D printer for $169 that can print this model and fly it - crash it - and print another. Or print a different model you want to try. Sure, you could try to get someone else to print it... but then you are relying on someone else for replacement parts and or making it worth their time. You can set up the printer to print all of the fuselage parts, or all of the wing parts, and push a button and walk away... come back later and you have parts. This is not insta-plane, it takes ~ 3 days to print everything with one printer, but way easier than many other building techniques. I encourage everyone to look at this as a new and evolving part of this hobby.

To me this is the best reason to own a 3D printer.

- Wayne (yes another Wayne)

Excellent stuff Waynesie - always was curious to own a 3D printer - but now it may be a good reason to actually pull the trigger on this - thanks for sharing this

 

[Wayne]

Finally flew my Roughgen in good weather. Yay! She flew very nice. Really good roll rate as I am using the flaps as ailerons. Landing was CAKE with the flaps. I actually pulled full crow, backing in towards the landing area and settled down very nicely.

I have a little roughness on the leading edges of a few panels I need to sand down. Had not noticed it during the build. Hope cleaning that up will pick up some speed and help with energy retention as It expected a little better speed and energy from her. She is a pretty clean plane otherwise. Not complaining, she is a fine plane, just think my build is holding her back a bit..?

If you haven't made one of these, I'd add it to the list of planes to get. I see myself abusing this a lot more in the near future. Will be used as a trainer.

Also, Wayne, I think this is a good flap slope trainer for folks. I have heard from a few people now that are unsure how to best use flaps when they step up to a flapped airframe. The Roughgen makes for a great trainer. If you can consistently land the Roughgen with no damage, then you will do fine with other flapped planes.

 

[Jman]

Guys id be really keen to try your Prusa MK3S+ settings as i cannot get the wing panels to print without issue....cheers

 

[Agarcia]

Hey, I just downloaded the Roughen V2 and after 15 wing test prints, I got it right. The final print, found the settings for cura in the directions, was perfect. I am using the Prusa slicer, so Cura settings don’t quite match. But 15th test print looked good. Printing right wing tip now

 

[Lee Bonney]

Hi Guys, Lee here from South Africa,

I've printed/flown the PIKA with a self designed power pod.

I could go into detail with some of the tips/tricks/mistakes during printing and assembly.
However, for now, lets skip to the flight properties.
I have the 4 servo wing & 1000 mAh 3S pack, AUW is about 950 grm.
On the first launch it just nosed in, never got "fingers on sticks'. Damaged rear fus & one tail feather.
Repaired and set both tail surfaces at an increased incidence.
Next launch 60° climb out! Corrected attitude to level it out, but two issues:-
Very sensitive/unstable on pitch axis, (CG 3mm fwd of nominal).
Very poor turning response, (adverse yaw).
Implemented "differential" travel on Ailerons, moved CG 1mm fwd.
Better turn properties, but v poor "non axial" roll, still pitch sensitive. Crow flaps very effective in slowing landing approach speed.

Overall, very disappointing compared to my Multiplex Blizzard 1.4m foam v-tail glider.

In a way, predictable, Blizzard has lower wing loading, relatively longer CG to stabs measurement, bigger motor & bigger (2200 3S) pack.

Not really sure how to improve the existing Pika, maybe go for higher power but the increased weight may cause CG issues.

Next Pika, may scale wing to 1.4m, and fus to be longer, new nose design for bigger motor & pack.

Anyhow, maybe someone else can share there experience of a powered Pika, particularly with a comparison to a another
V tail glider?

 

[Wayne]

Have not flown the Pika, but assume it would be about the same as his other designs.

You mention a self made power pod - These will and DO cause issues with a model and the thrust angles must be tuned to limit the problems. In general I am not a big fan of pod mounted power systems for this reason. If and when possible, keep that thrust line as close to the center of the wing as possible. You will be rewarded with much better handling.

I will say that my time with the Roughgen, a very similar design was pretty much on the numbers for CG and throws and was a very good flying model. I think some of these have been pushed close to 200 mph now. Not bad for a printed model.

Adverse yaw is pretty common on gliders and aileron differential is the common solution.

Incidence on this model should be fine, again, I think what you ran into was your high thrust line and no thrust compensation built into your pod.

Similarly, CG on these models is well documented, but not everyone likes the same feel from a model. The suggested CG is intended for slope glider use, and we like rear CG on our slope gliders as it really allows the wing to work for us. A nose heavy plane is very common in the power model side of the hobby as it is safer and you can simply add more power to make it seem like the plane is flying better. But reality is a more aggressive CG will allow the plane to fly better in almost all realms of flight.

Hope this helps some.

 

[Lee Bonney]

Hi Wayne,
thank you very much for your prompt reply.

I think you are assuming my motor is mounted higher than the wing, and I agree this causes thrust-pitch issues, however my motor thrust line is in fact just above the axis of the fus
cross section. It has about 2 deg down thrust and 2 deg right thrust. In fact there is no detectable pitch change between full/zero throttle.
My reference to the MPX Blizzard is long established, been flying these for 10 years and been through about five of them (two remaining) I run CG at about 50% chord on these.
I think my core issue is fitting a 6S drone motor, T-Motor F100, but only running on 3S.

I'm going to fit an e-flite 480 930 Kv, it's a bit heavier, but currently running tail ballast, so this will likely "balance out" to zero net AUW.
Remember that I don't have any slope lift, and sit a more than 5000' altitude, this can make launches challenging with a high wing loading.
I want really good speed, but figure that getting it will need adding a LOT of weight. Frankly I'm only running a hollow 6mm carbon spar, whilst th, e
MH32 aerofoil calls for a 7mm solid spar, with added weight this could be terminal, but wouldn't be the first plane I've had break up md air.
I've ordered 7.2mm/6mm arrows, "carbon mix" material, these will be used to sleeve over the said 6mm spar for the next wing.

So not giving up yet, but a long way to go to match a Blizzard.

 

[Wayne]

Yeah, hard to beat the Multiplex planes at what they do, generally well designed and manufactured products.

Not sure the Pika is really going to get you where you want to be, but sounds like you are having some fun in the process, and no doubt learning a ton with the printing and design side of things. Keep at it, and have fun!

For electrics I really like the "Plane Print" 3D designs. They have some well thought out models that actually do pretty well for 3D printed models. The Soarkraft is really at home on a slope, but honestly have not looked at their newer stuff in a long time, so I could be 1000% off.

For speed on a 3D printed platform, the NuckingFuts was a pretty good airframe in the past. I think it is a free download too?

Nucking Futs - Speed 400 Pylon Racer - RC plane by tahustvedt

Flight videos:https://youtu.be/XXQ9nKR_kTghttps://youtu.be/UxittfJNad4https://youtu.be/3M_5ZInhubwhttps://youtu.be/GIJgPmEvhx4EDIT - 14.04.2019:Added a glider nose and front fuselage piece which is longer and without holes. The new files are Glidernose01 and Fuselage01-gliderEDIT -...

www.thingiverse.com

I printed one of these many years ago. Here is a long build thread.. Hope you have some time:

Speed 400 Pylon Racer - Nucking Futs - RC Groups

Discussion Speed 400 Pylon Racer - Nucking Futs 3D Printed Planes

www.rcgroups.com

Or you may have already done one of these?

 

[Lee Bonney]

Hi Wayne,

thanks for yr reply, and apologies for the delayed response.

Re speed 400 PR, in fact I had a full composite one years ago, the speed was amazing, but landing it was a problem.
Got damaged, but I bought a replacement wing, has been gathering dust since.

Re Pika,

I grafted a Bizzard wing on the Pika (1.4m vs the Pika's 1.2m). Also replaced the 11x8 3S power with 9x6 4S.

Better results, but still rather unstable in pitch, and very unstable on approach, but the wind was turbulent due to the terrain.

Next step, replace rear fus with 12mm carbon tube (longer than original and a lot lighter). Battling to get a top quality print of the stabs.
Hope my P1P printer (arriving next week) will do better.

Rgds

Lee