Building a Balsa Glider With a Precise AG47 Airfoil
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- Опубликовано: 1 авг 2024
- Hey folks! This is one of my most information-dense and thorough videos so far. I walk through the entire process of constructing a very aerodynamic balsa glider, with a focus on shaping the wing into a measured, calculated, highly accurate AG47ct-02f airfoil. I describe some reliable methods for fiberglassing, fuselage and tail surface construction, and finishing aesthetic detail.
This may well be my last video, as I’m going off to university in a couple days and will have less time for producing videos. I do hope you enjoy it, and I would be pleased if you could share it with friends and help me get it viewed. As always, I thank you all for watching!
The music here is the Courante from Bach’s Cello Suite in G Major BWV 1007, played by me on F tuba. 
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![J.P., NLE Choppa - Bad Bitty (Remix) [Official Music Video]](http://i.ytimg.com/vi/rBDa6BCvw10/mqdefault.jpg)
Beautiful build, and such a pure way to bring a plane into existence, great job.
This channel is like a step back in time. The music and the way you speak. Very fun.
Oh! That is perhaps the most wonderful impression anyone has ever expressed to me about my work here. You have no idea how much that means to hear. Thank you very much.
@@AeroCraftAviation you're very welcome! I am excitedly waiting your next project.
A very fascinating and educational build process with entertaining presentation.
Beautifully done! Your voice-over narration of the build process is really entertaining and well thought out. Congrats on the build and I hope you get a lot of good flying out of it.
Thank you! Glad you enjoyed. :)
Really fun no-nonsense build video.
Thanks for sharing, and good luck with University!
Thank you!
Very nice and precious work! You are the master of balsa glider making. Thanks for sharing.
Thank you for your kind words!
If this were Your last video (which I hope You didn’t) to share with us I’m very glad You published one of the most beautiful human creations in the world in the form of a DLG playing some beautiful music.
Dude. Sweet. So creative as well as technical. Props!
Thanks man!
Great to see a new video. You put lots of detail in here 👍👍
Always good to have the detail appreciated. It really was a mountain of editing. Haha.
That’s lovely work, and a fun technique for obtaining a nice wing section that your glider deserves. Good luck in school and thanks for cool clip. -Carl
Nice tuba playing!
Your voice-over sounds like a journal entry in my chemistry lab book. Well done sir.
Awesome build video, best yet.👍
Thank you! Haha I saved my best for last.
Bach for ever!!
Yeah woo!
That's an effective way to shape that wing. I really like your old-school approach. Hand-carving/sanding is a lost art and there is only one way to learn it! I am currently working on improving my wing shaping technique and I will use your ideas.
It really is. Upon further flying and trimming, I was really surprised by how much this glider shares the performance tendencies of composite gliders that use AG airfoils. The systematized sanding really does pay off! I've always loved this kind of hand-working. I hope to always keep at it, at least every now and then, so as not lose my skills.
@@AeroCraftAviation Thanks so much for posting. I have no time to do this kind of video work in my life and appreciate those who do. - great work, BUT... buckle down first semester and get the university habits and life under control. it will serve you well. Once you establish how much time you need to devote to studies, then the hobbies can come back. You may even find some new ones. Great time in life. JHU 1975-79, U Penn Med 1979-1983
@@nategraham9350 Thank you for your compliments. I was very happy to take the time to make these productions when I could. Now at university I find it necessary to devote more or less all of my time to university; whether it is studying, music, making the most of the clubs and organizations, meeting people, or any other university-specific engagement. Really, there is little time for my hobbies as they were during high school. But I am thoroughly enjoying it.
Very clear explain brother 👍🏼👍🏼❤️
As usual great video and great build. Good luck in school. Its obvious that you will be making a difference.
Thank you! That means a lot, truly. :)
Flyboa is the foam master, and you sir is the Balsa master. Thank you for this awesome video.
And thank you for your kind words!
"a filos" is great, too
@@marc_frank I've seen his videos just yesterday, omg now I'm excited about the fiberglass wings! It's a "professional" diy glider, it's really an incredible work, and you can throw it to new heights! I'm gonna try it as soon as I have some time, hopefully also record the whole thing.
@@FTSsjc that'd be cool :)
@@marc_frank He is also a great master of the craft. My composite wings have never been as good as his. He really has the process worked out perfectly. His gliders gp great.
great video!
Świetnie wykonana praca ,
Like the background music😀
Good job mate enjoy Uni
very nice bravo
Nice!
Really like the profiles of this plane. Can't wait to see what you produce with fancy CNC equipment at RPI! Go forth and make a difference!
Thanks man! It's gonna be cool; I'm psyched.
recently discovered your content. Im sad to see you go, but i have thoroughly enjoyed your content
Glad you enjoy the videos. I will really try to keep posting. I just can't ensure that completely. So it's best to say I won't be posting. But maybe... once every now and then. Haha.
I have zero interest in aviation or woodworking, but my god, what a well-made video!
Man you have no idea how much it means to hear that. I have always been rather unsure of my editing skills. It is really great to hear that you enjoyed the video. 🙏🏼
WWWOOOOAAAHHH ... I carve props (microlights) ...bro that was nuts ♥♥♥♥♥♥♥♥
Nice
I didn't understand how you mounted the spring on both rudder and elevators, Would you make a short video showing how it works?
Hey there mister! Just thought I'd drop you a belated "Happy Holidays", And a "Best Wishes" in your endeavors in higher education. I hope life is treating you well.
Good to hear from you. I am doing well. Really busy. I started an indoor free flight group here at RPI, still in the early phase and having to put in a lot of effort to get people into it and get it up and running. And I'm doing 20-credit semesters which leaves me with no time to make videos. But I still do some little builds every week or two when I have a few free weekend hours. All the best to you as well.
@@AeroCraftAviation Thanks for your email. You might want to edit it out now.
@@somethingelse2740 My plan exactly
God bless 3D printing and CNC milling
Shaping soft balsa is actually very difficult to do by CNC milling. I have had only marginal success with it. And 3D printing is far outside the weight margin for sucb a wing (there are some internal lattice designs that come close, but are still at least 30% heavier than a balsa wing of equivalent strength).
To get a more accurate wing shape, the best approach is to go foam-core carbon fiber, using CNC-milled aluminum wing molds -- which ARE quite straightforward to make.
How to make head on view? Is still dont understand, do you have any video of it?
Very well done production and build sir! Now that you are producing your own music for the background it is even more impressive. Keep up the good work and good luck at school! Who am I kidding, you wont need luck, you've got skills and a sharp mind to back them up. Best wishes.
Thank you for such kind words, man, really. I am glad, and in part relieved, to hear that the music is indeed pleasant or at least not obnixious. Haha. Really wasn't sure how the reaction would be to 11 minutes of tuba. I seriously can't wait for college. 3 days away and the suspense is killing me. 😂
@@AeroCraftAviation as long as you keep the narration to background music volume ratio about to about 1/2 of the narration level, you could probably add kazoo music and it wouldn't be too obnoxious. ;-) I went to your music practice section and listened a bit and was quite surprised at a few of the low notes a tuba can output. is that all tuba or more on the lips of the player? Also impressed at your quite fast fingers and how you can voice-over while playing to get those "chords". I had no idea. You keep learning and practicing everything that interests you and there are really no limits (that I can see) for a guy like you.
You shouldn't worry about college, you'll have no problem. Just don't fall into the college partying way of life and you'll be fine. I've seen really smart nice guys succumb to the alcoholic lifestyle in the army and they got dishonorably discharged.
The one guy was literally the nicest guy I ever met, his only vice was addiction to chocolate and he performed magic shows for kids as a teenager just before he joined the army. He didn't last a year once he became addicted to booze. So sad. Addictive personalities, it's thing. Be aware if addiction is part of your personality. As long as you are only addicted to models airplanes or making music it won't be so bad. ;-)
@@somethingelse2740 The low end of the instrument is defined by physics. The instrument's lowest, fundamental open partial is C0 (for a C-tuba) or F0 (for the smaller F tuba). The instrument's valves lower the pitch as: 1st valve: whole step; 2nd valve: half step; third valve: minor third; fourth valve: perfect fourth; fifth valve: flat whole step; sixth valve: flat half step. So with all the valves depressed on my 6-valve F tuba, we can play 2+1+3+5+2.5+1.5 = 15 half-steps below the F0. Of course, with that much tubing opened up, it takes a lot of breath control and a very skilled player to actually get the resulting pitch (a rumblingly low D0) to sound. Also the plethora of curves and squiggles in the slide tubing will cause the pitch to sharpen a lot. On a tightly wrapped instrument, upwards of a whole step may be lost. So we can say physics allows us an E0. A masterful player may be able to lip that back down to the "ideal" D0, or even to the C0. But at that point it's basically elephantine infrasound... Lol.
The high end of the instrument is basically limitless. It's that way for all brass. It is, after all, just vibrating lips. The instrument is nothing more than a tuner and amplifier. Theoretically, with a masterful embouchure technique, every brass note is possible on the tuba, since the entire lips are used in the large mouthpiece and there are no limitations. But in reality the extremely high pitches do not resonate in such a large horn and so they end up sounding like mutant mosquitoes. My high range extends reliably to the D above middle C. Much higher notes are psosible, but not reliable (and often strenuous and uncomfortable). This guy has an insane high range that demonstrates the mutant mosquito sound perfectly: ruclips.net/video/s-bMVbhB9DA/видео.html
I am fully prepared to exercise a new level of discipline and self-policing to keep myself away from the party lifestyle. I have always adamantly told people that such a lifestyle doesn't interest me in the least, but I'm sure aspects of it will have their appeal. I will keep tight control of my time expenditure and habits. I want to use this valuable time at an affluent and high equipped scientific institution to my best advantage. I, too, have known people to fall off the bandwagon at university and perform much more poorly than they wanted to. I have seen it enough to be deeply motivated to avoid it.
@@AeroCraftAviation elephantine Infrasound is delightful. And that guy you linked sure does play some pretty trippy tuba. I made the wife listen to it fairly loud. LOL!
Sounds like you have your mind set in the proper mode for the many accomplishments that will surely be in your future. You've already done and learned a lot more than many your age. Keep at it mister!
@@somethingelse2740 Yes, he really is a master of the instrument. Does jazz and classical and contemporary stuff. I got the opportunity to briefly study with him when he did a week of classes and recitals at DePaul University, Chicago, during his U.S. tour. Experiencing a professional tuba soloist live is... other-wordly. The sound is massive.
Thank you, again and as always, for your earnest compliments. They are well received. :)
I like how the control horn is a Nr.7 blade, or at least it looks like one (:
Good morning gentlemen.
Where can I find the design of this model or likeness?
Thanks
I use a similar idea with tape to protect surfaces next to each other. When the tape starts to get thin, it is time to stop sanding with the coarser grit and move to a finer one. Great work and technique. Noticed your audio sounded a bit low in volume and muffled on this video, had to listen very hard at times. Hope all goes well at uni, may I ask what you will be studying?
Yeah I maybe should've included that detail too: that as the tape thins out one must be careful not to sand through it and so finer grit sandpaper becomes more suitable. It's funny, the audio on this video is globally up about 40% from all my others. Might be something happening with playback on you end. Could be a problem of sound pressure, because voice has a lot of sibilant frequencies and low brass background music has a lot of low frequencies: that sometimes confounds small speakers.
Great work! Curious about the tuba playing in the background?
Thanks! That's me playing Bach BWV 1007 Courante. You can find my music here: open.spotify.com/artist/59EX2unQ4V0xRxes7wQjyQ
Only three tracks for now, but more to come. I will hopefully release a full album of selected Bach cello pieces at some point.
Also find my music content here: ruclips.net/channel/UCllXXtqBrYgYexW4F2YIytQvideos
And also here: instagram.com/tuba_practicelog/
nice music...👍
Thank you!
Thank you for this building video. Very educational building the aerofoil. I will definitely give it a try. Lovely job.
What are you studying at the university?
I am glad you enjoyed it. I will be at Rensselaer Polytechnic Institute, studying Aeronautical Engineering and Chinese Language.
You'll do great at Uni, and that's a great school. My sweetheart's late hubs went there, playing hockey! He was into flying and rc as well.
what would you recommend as a beginning rubber band plane Would like to try some flying with my grand daughter thank you
This was one of my first: sigmfg.com/products/sigff1-sig-cub-kit
Easy to build and flies great. Also this one:
These are fun too: www.pitsco.com/Delta-Dart-Model-Airplane
Can build one in an afternoon, and they will fly about 45 seconds when built well.
These are fun too: jhaerospace.com/product/hangar-rat/
Nice bird and Bach suite in the background was very nice.
What recording is that?
That's me playing on F tuba. You can search my full name Elihu S. Conant-Haque to find more of my music.
@@AeroCraftAviation
Whoaaa. Impressive. I will google that name for sure!
Thx.
@@AeroCraftAviation Elihu,
Would you build me one?
ruclips.net/video/N6WcTuFB6RU/видео.html
I would want it signed ! LOL
That might even help paying your College, tuitions!
Sorry I might have missed it, what radio and battery did you use?
Radio is Spektrum DX8 G2. Battery is 1S 150 mAh 25C LiPo.
Very nice! It goes fast too with that weight!
Good luck in college! That's probable also why it has been 9 months since this video I assume? ;)
Yep that's exactly the reason. I am trying to still build aircraft. But I barely have time for the building. I don't have time for the video editing. Perhaps a couple videos by the end of this summer though. I finally have some free time.
Sounds good, definitely prioritize school! Enjoy building, I'll be looking forward for the reports on the new builds :)
I am intrigued as to why you used AG47 for this. Mark Drela created a range of airfoils for DLG's from AG03 to AG19 to be used progressively from root to tip in "family" combinations, yet you chose a specific tip section from a more advanced combination intended for ailerons, designed for the Apogee 2. Did you check its performance characteristics at appropriate Reynolds numbers with X-foil or W.H.Y. before selection?
Sorry for late reply here. Yeah at the time I checked the performance numbers at low Res. Simply used the Airfoiltools data and interpolated I believe, didn't use X-Foil but actually I don't see why I couldn't have. For other aircraft I use it where needed. I'm not sure what exactly the target performance was -- this was a while ago and all the documentation is scribbled down in a notebook somewhere.
@@AeroCraftAviation I was also in error here. it was used on Supergee! I realised after I posted that you had moved on to Uni and probably would no longer check it. I suppose I assumed you were fairly familiar with Drela's work, because your sanding technique was similar. The main inconsistency is that it was designed for a flapped wing, which as you will now realise usually means a narrower drag bucket with excellent performance over a smaller range. The low number ones were designed for 2 channel, so have a wider speed range at a slightly lower overall performance. It is rewarding to see someone of your age taking this rational, scientific approach compared to much of what is posted . My biased point of view is probably because I have reached the age where I can no longer launch a DLG without going into rehab for a week afterwards! Best wishes.
@@petegarnett7731 Yeah I guess at the time I must've been aware of that. The main consideration was this: Given the thickness and width of my piece of balsa, I was limited a specific relative airfoil thickness of about 5%. So if I want to directly use the data from airfoiltools.com I would have to limit myself to airfoils around that thickness (knowing that at low Re the performance doesn't behave predictably as one stretches or squishes the airfoil vertically) Out of the various airfoils around 5% thickness, the ag47 was the most desirable. And also it was the closest to 5% so its data were most representative of the wing I would buid. I think that's really why I chose it -- the convenience of being able to read data right off a table.
The main wing should not be cut at center. Balsa has a high strength to weight ratio along its length through the grain. You lose all of that when you cut it. Then you have to try to rebuild that strength back with all those methods and extra weight, and it's still not as strong. Soak the center of the wing for a long enough time to get a tiny amount of dihedral, without fracturing the center of the wing. Then ad a layer of fine fiberglass cloth and epoxy fast hardener to the center 3", of the wing top and bottom. It will be so strong you can attach the wing to the fuselage with lateral 1/8" dowels, and rubberbands going over the top of the wing, hooked on the dowels sticking through the fuselage just under the front and back edge of the wing at the outside of the fuselage
Also, on your next plane, try moving the main wing back an inch, and the RC box further forward for more forward nose weight, to help the balance of the glide trim.
You make an interesting observation. The dihedral you see on this aircraft is about as low as possible. We need at least that much. Surely there is no way to bend balsa, especially not 1/4" C grain balsa, to such an angle. And since the trailing edge is sanded so extremely thin, soaking the wood is out of the question; it will warp badly. We could try to heat the wood to weaken the lignin, but then we risk burning it. One method is to achieve the dihedral by gradually curving the entire wing. I have never tried that and it might be a good idea. A slight curve throughout the whole wing might be achievable with minimal steaming. I suspect over time the wing would tend to straighten out, though. Such a curve would also put the wingtip at a pretty steep dihedral angle ralative to the root, which would make the throwing somewhat logistically awkward. But it could be tried.
As for the lateral dowels, that is tricky. They would create a lot - a lot - of drag. So they cannot be allowed to protrude from the fuselage. All attachments must be internal. The problem is that the rigidity of an attachment depends upon the force moments. The extremities of the aircrafrt have a greater moment around the inside of the fuselage. If we're talking about some sort of internal modular wing attachment, we must remember that during the throw, the force moment of the wingtip about the point of wing attachment matters a lot. There is a LOT of force there. Every millimeter of leverage counts. So I think if we put rubber-band-dowel attachments inside the fuselage, they will not be nearly strong enough to hold the wing in position. Besides that, the attachment will add a lot of weight. Rubber is a very heavy material. And to achieve a rigid attachment, we would need a lot of it. Probably 8 or 9 grams of rubber bands to even barely hold the wing firmly enough in place for a light discus toss.
You mention increasing the size of the nose. I am very reluctant to do this, since firstly the aircraft is designed to balance with this configuration and in flight it does balance very well. But more importantly, the fuselage adds a lot of weight and drag. The more we can minimize the non-lifting, drag-inducing, stuff-carrying section of the fuselage, the better. I put a great deal of design effort into minimizing the length, width and breadth of the fore fuselage section. So yes, we can increase the size of the nose and move the wing back, but the aircraft will perform more poorly, so it should be avoided.
Was all the pieces of balsa being heavier on the same size a coincidence?
Yeah, just happened that way. Although I can kind of feel which side is going to be heavier, so I probably subliminally oriented them that way when i picked them up.
Do you think a DLG with a 30 inch wingspan would work?
Yeah, it won't glide terribly well on account of the small size, but for sure it'll work just fine. Here's a really little one I made: ruclips.net/video/7Acb_PBHXWw/видео.html
@@AeroCraftAviation sweet, just wanted to make sure, it's just a concept but I was thinking of making a DLG that would be used for Dynamic soaring in strong winds, it's wings would be made out of carbon fiber plating to handle the strong loads (some dynamic soaring gliders can experience upwards of 100 Gs) the only carbon fiber plates I could find for cheap were only 15" long and I wanted to make sure it would work since I can't find much of anything on 30" dynamic gliders or DLGs. I'd make the wings the same way you make your wings but instead of balsa it would be 1/8" carbon sheeting. I'd have to add a bit of weight to the fuselage though to make it work as a dynamic soarer so it could punch through the wind. Check out dynamic Soaring gliders if you haven't already, it's amazing the speeds these fragile looking planes can reach. The worlds fastest RC plane is a DS, no motor on it at all and it reached 548mph. Anyway thank you again :)
@@RicardoRodriguez-mh7my Yeah well the structural requirements would be very different for your little glider -- you know, square-cube law and scaling effects. So you won't need all the crazy rigidity those big DS gliders like the Kinetic need. But because of lower inertia, what you WILL need is extremely fine aerodynamics. I'd recommend using a very hard sheet of 1/4" thick balsa (a piece weighing 80 grams or more) and sanding an airfoil shape like in the video. (Might need to use a planer for the denser wood). Then, vacuum-bag the wing with a few layers of carbon fiber cloth and 48-hour resin. That'll give you all the strength you need even for really high-G DS. Make sure to get the trailing edge really tightly joined. The most likely place where a homebuilt layup wing will fail is at the trailing edge, where the pressure gradient might pull up the carbon skin. You can also cut a slot down the wing at the airfoil high-point and insert a spanwise carbon spar. Make sure to rough up the carbon spar surface so it really adheres with the wood. Good luck with the build! :)
@@AeroCraftAviation That's true, thanks for the advice, your wing idea with the bagging would probably be cheaper as well XD. When/If I get around to it I'll maybe send a link to the finished product :)
I miss your videos! got any plans for posting soon?
Ah, I don't know, life is just so busy with college. Maybe after Spring break I will streamline my schedule, drop out of some clubs and groups, so as to make time for these builds. Maybe also I should lower my standards, post some simpler videos that are easy to make. I will think about it but realistically probably won't post videos any time soon. In any event, I am certainly glad to hear that you enjoyed my videos. Thank you!
@@AeroCraftAviation i seriously miss this channel
@ Aw man that's very kind of you to say. I have to get back to it, I know. The "too busy" excuse is getting old. Hmm... I dunno. I keep trying to put videos together but it just sucks up too much time.
How i do it... i make 2 metal or printing plate ribs... the base and the tip rip... i glue them on the ends (wings can be made in more than 1 piece) ...so lets say 4 pieces, sanding it into the profile with a plat square iron bar, it has weight, so you use the weight to sand.
And i glue the parts together, and then i make the winglets and glue them on there
Yes that method works well for the shape, but the structure isn't very strong because the wing sections have to be joined end-to-end. So for a hand-launch glider, that method can't be used. But for a motorized aircraft, or for a hi-start glider, or for a slope glider, yes that method works great!
@@AeroCraftAviation i did built a 1m DLG like that😉 works fine if you know how to strenghten it.
I launch mine up to 35-40m with no problems
@@jasmijnariel You must have a spar or something running along inside the wing to join the pieces. Or maybe you do a lap joint where the pieces meet edge-wise? I'm interested in how you can get such a rigid wing that way. Because I have tried that method before but never got a very rigid result. You should post a short video showing the aircraft and some build photos!
@@AeroCraftAviation yes i had a plywood spar in between the joints and fiberglass reinforcement
@@AeroCraftAviation you should check the mimi DLG
you can buy wood flour works great and very light
Oh cool, good idea!
Hey we miss you! Will you ever return?
It's nice of you to say that! But I'm just so busy. Taking 20 credits this semester, applying for internships, participating in research, working on a solo album in the recording studio, the list goes on. Yes, I do still build. And I even take some photos and document some of it. But it never ends up being enough for a full, thorough video, and besides I never end up having the time to edit the videos. Editing and recording the narration is time-consuming, as it turns out. (I've only fully realized this now that time has become such a commodity for me).
@@AeroCraftAviation don't trade your walk on part in the war for the lead role in a cage.
Balsa... 😳
How you make this? 04:33 sorry my english is not good
Hello
Trumpet? Really?
F tuba, but high range mostly so similar to trumpet.
I'd lose the cello...
can you speak a little slower please
I do my best to fit a lot of information into a short video; I don't want to waste anyone's time. But I do apologize if it's hard to understand
This is incredibly annoying. You talk way too fast and the trombone was extremely distracting. I’m sure you had a lot of good advice and information but it was completely lost in the noise.
Agreed thoroughly, along with other commenters.
@@AeroCraftAviation Sorry, they seem not to agree. I found it hard going. Everyone else seems to like it.
@@thethirdman225 Sarcasm, my friend! It makes the world go round. But in seriousness, I do thank you for your feedback. Honesty and clarity like yours is valuable.
Beautiful build, and such a pure way to bring a plane into existence, great job.