Vulcan: L1 cert glider

Status update: I successfully certify L1 with Vulcan at TCC October Skies on Oct. 19 using a CTI H54 motor.

Vulcan now has 21 flights and counting: 4xG54, 2xG69, 2xH54, 1xH73, 5xH112, 3xH123, 4xI49.

First flight (10/9/2012; video credit: David Springsteen):

[video=youtube;DOoQHrTUDTY]https://www.youtube.com/watch?v=DOoQHrTUDTY[/video]

Second flight (TCC 10/19/2012, L1 flight @ TCC October Skies): https://www.youtube.com/watch?v=-2NGnNFEE9Y (video credit: Steve Sawyer)
Third flight (TCC 10/20/2012 @TCC October Skies): https://www.youtube.com/watch?v=q5Fk8XjnliY (video credit: "Minimum Wage" Mike)
Fourth flight (LUNAR 10/27/2012 @LUNAR Moffett): https://www.youtube.com/watch?v=Qt2NY6224kk (video credit: rbelknap)
Fifth flight (11/3/2012): https://www.youtube.com/watch?v=UOeQk790-yk (video credit: Nolan Leake)
Sixth & seventh flights (11/24/2012): www.youtube.com/watch?v=mTV1_q2oiHw (video credit: David Springsteen)
Eighth flight (1/5/2013 @LUNAR Snow Ranch): https://www.youtube.com/watch?v=sWmTcx7AKP0 (video credit: "qquake2k" Jim)
Ninth flight (1/12/2013 @SARG): https://www.youtube.com/watch?v=RIbdjWSHezg (video credit: "qquake2k" Jim)
Tenth flight (2/16/2013 @LUNAR Moffett): no video
Eleventh & twelfth flights (2/17/2013 @SCCMAS): https://www.youtube.com/watch?v=sTayTlVdOdQ (video credit: Walter Colby)
Thirteenth & fourteenth flights (2/24/2013 @SCCMAS): https://youtu.be/2CNbHRUeeqE (video credit: Walter Colby)
Fifteenth flight (3/2/2013 @LUNAR Snow Ranch)
Sixteenth flight (5/19/2013 @ TCC Dairy Aire)
Seventeen-nineteen: SCCMAS airshow 2013
Twentieth & Twenty-first (7/6/2014 @ SCCMAS): https://youtu.be/8Owa_4T7e68

Photos from October Skies by Martin Hall (hi res versions and many more photos at https://konoctipirate.smugmug.com/Rockets/October-Skies-2012-Friday):



Another photo from Martin, from January 5 Snow Ranch (more at https://konoctipirate.smugmug.com/Rockets/Snow-Ranch-LUNAR-010513/27431147_jvKr9J)

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Below is my original post from 9/13/2012. Read on to follow original and ongoing development.

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I'm building an RCRG for my L1 cert. The basic specs are:

Wingspan: 43"
Airfoil: NACA0015
L1 attempt motor: H54 (3-grain pro-29); 38mm inner tube can accommodate I49 or even I59
Fuselage: 54mm tube
Custom foam cores by https://www.flyingfoam.com/

The name derives from the planform and its superficial similarity to Avro Vulcan.

This build incorporates my experience from this project. The main takeaway is that a small glider is impractical for HPR on two counts: 1, it's difficult to see at altitude; 2, L1 motors can accelerate it beyond structural limits. Simulations suggest the 2' glider might reach 600mph, which is well beyond the airframe's capacity (and my capacity to control it). Therefore my goals with this design is to build a larger, draggier, heavier glider. This is contrary to my intuition and experience and a novel exercise in this sense.

The wings are quite massive--larger than any of my existing models. The 2' glider and my R/C transmitter give a sense of scale.

Ari.

Wow - this is a fascinating and ambitious project. I don't recall having ever seen someone certify on an RC glider before. I'll definitely be following this thread, and let me be the first to wish you the best of luck with this. When are you expecting to fly?

As befits an HPR model, Vulcan has through-the-wall fins. Well, the one fin it has is through the wall. To increase glue area, and to simplify alignment, I laser-cut a fin-can with interlocking centering rings and longerons. The fin is removable; its saddle attaches through the wall. MMT is 38mm. If Vulcan survives my certification flight, I want to try it on I49. I'm planning to use an H54 with a 38-29 adapter for the cert flight.

The launch lug runs the length of the fuselage and under the fin. Putting LL above the CG means that the model hangs right side up on a launch rod. The laser-cut structure accommodates a 1/2" LL tube.

This is the first model where I cut my own TTW holes. I use a pin to prick the corners of my openings to give the knife a definite stopping point.

I cut little supports for the launch lug. The lower radius fits the outside of MMT, the upper radius fits the LL. The height matches the vertical distance between corresponding cutouts in the foam core. The number of dimensions that must fit together is making me think that I'm over-engineering Vulcan.

Dry fitting goes well tonight. Tomorrow I start spreading glue.

Ari.

Thank you for your encouragement cjl.

Two dates are approaching for certification: TCC October Skies (Oct 19,20,21) and LUNAR Snow Ranch (Nov 3). I usually fly with LUNAR, but the November date, the first of the season, is uncertain. We need rain before we can fly at Snow Ranch. TCC, a little farther out of my way, is a year-round site.

I want to fly Vulcan on a G54 before either of these dates. I fly LPR and MPR gliders at an R/C field about 20 miles South of here. There are also LUNAR launches at Moffett on Sept 29 and Oct 27. Moffett restricts us to G motors and 1000' ceiling. I might fly Vulcan there on a G54.

Ari.

Saw my original post didn't go thru. Beautiful bird! As a teen in Britain, I thought these were the most beautiful planes in the world-sleek and powerful. It looks like you're doing a bang-up job-carry on! Best wishes for your cert flight.

Thank you for your encouragement and your wishes fyrwrxz!

Ari.

Cool project! Have you contacted the person that will be signing your paperwork to make sure they'll accept this as meeting the new "active recovery" requirement? The NAR wording of that is at https://www.nar.org/2006/07/definition_of_active_recovery.php

The Vulcans are fantastic planes. Defintely the Brits has a star plane suring that period. I agree with the above posters. I have never seen a glider as a level 1. I am very support of you ingenuity and will continue to follow you buidl and flight. Good luck.

I have though about building a high power helicopter recovery. I just have not had the time.

That looks like a good solid vehicle there, Ari. That H54 seems good for this, especially if your bird is neither too light nor heavy and you can control it on the way up. I've flown some HPR gliders pretty darn fast way long ago, but these were all free flight. A J415 in a 12lb rocket seems 'slow n low', but the same load in a glider seemed *FAST*!! Barely held together too.

Might be doing an I284 in a glider this Saturday, if the motor is available and *someone* loans me the necessary hardware.

I think you'll do just fine, and the I49 would be not very far behind (initial spike on the I59 might be an issue though).

Awesome project. Flyingfoam does awesome work in my experience.

How do you plan to cover the foam cores?

I am still amazed that you get to launch at tomcats!

BTW I launched a phoenix on an F50 once......Scary!

How long did it take to shape the wings out of foam? Did you use a razor plane, or some other method?

AstronMike said:

That looks like a good solid vehicle there, Ari. That H54 seems good for this, especially if your bird is neither too light nor heavy and you can control it on the way up. I've flown some HPR gliders pretty darn fast way long ago, but these were all free flight. A J415 in a 12lb rocket seems 'slow n low', but the same load in a glider seemed *FAST*!! Barely held together too.

Might be doing an I284 in a glider this Saturday, if the motor is available and *someone* loans me the necessary hardware.

I think you'll do just fine, and the I49 would be not very far behind (initial spike on the I59 might be an issue though).

Click to expand...

You didn't cert on a glider, did you? Actually, I'd be kind of surprised if you hadn't.
Fingers crossed for the I284 glider this weekend!

Iter, good luck with your certification-- that's a very sturdy looking glider if I ever saw one. BTW, how much do the electronics weigh? For that matter, how much does the whole thing weigh?

Wow guys, thank you for all your support! Your encouragement is great.

@will: sharp eyes on the lawyering side. The document you quote specifically lists R/C as active recovery and really, it can't get any more active than active control by radio. A parachute "actively changes the physical configuration" once. I continuously change my physical configuration all the way down! And yes, I have a number of people locally who are stepping up to certify my flight.

@chuck: thank you for your encouragement. I like to do things differently. I'm a hacker. I hack software, hardware and rules. Perhaps I'm missing out on a legal carrier :=)

@mike: free-flight HPR gliders sound like an easy way to lose them. A 10:1 glide ratio from 1,000' is a 2 mile walk, assuming I can find it at all. My original motivation for certifying on a glider is losing a LOC Hi-Tech in my first L1 attempt. I want a way to bring it back! Your other observation about low and slow is spot on. J415 would be low and slow in a 12lbs glider. The glider would be hella fast on the way down though!

@matt: I plan to paper the cores and then cover them with New Stuff laminating film. This is a new technique for me. A feature of the design is lack of spars. Strapping tape and covering are the source of torsional rigidity. The key is enclosing the body tube in foam so that tape and covering can go from one wing panel to the other. I'm very happy with how this works out on the 2' glider--that one doesn't even have foll covering, only packing tape across the wings. Do you ever fly at Tomcats? They have turbines and really big gas models there, and Bob Parks flies his Phoenix there. Before I join, I secure the club president's agreement that I fly RCRGs there. The first few times I come there however, countless helpful locals point out that RCRGs are illegal, against FAA regulations, void AMA insurance, against club policies, etc. I have to show them the email exchange. It's a little like flying oddrocs at a certain kind of club launch :=) Eventually, though, people accept me there and I enjoy my membership very much.

@rb: Flying Foam takes between a week and two from when you send you them your drawings to when they send complete cores to you. The electronics are fairly light. 5 servos @19g and RX @10g make 105g. I can use any battery from 50g, though I may need ballast in the nose, so I might use a larger battery as ballast. For all-up weight, I'm toying with the idea of building it under 1,500g with H54 to stay under FAA's "Class 2-High Power Rocket" so that I can fly HPR without an FAA waiver.

Ari.

I glue the motor tube into fuselage and add an AeroPack retainer.

I also glue in the integral launch lug--I include an obligatory through-the-lug photo.

Fin is removable; fin saddle has 3 holes for retaining bolts. I use it now only to align the saddle--hence the clamps.

Ari.

Rocketbuilder said:

How long did it take to shape the wings out of foam? Did you use a razor plane, or some other method?



You didn't cert on a glider, did you? Actually, I'd be kind of surprised if you hadn't.
Fingers crossed for the I284 glider this weekend!

Most of those old HPR gliders were made with two ply foamboard, usually the stiffest subtypes I could get back then. Iter, since he's a 'real aircrafty guy', is going the conventional shaped-foam route, which enables him to mold in an airfoil, something my stuff always lacked

I flew HPR gliders before the current multilevel cert system existed. Wound up lapsing my TRA membership, and had to recert L1, which did indeed use a glider, which I feel is the epitome of 'active recovery'. That was 'only' an H97 in a mailing tube based gliding Bomarc. Have only done a few other H/I flights since, as I cannot afford HPR on any consistent basis.

I do want to use the Maxi Astron SST for L2, though, obviously NAR too. That's why I want a second shakedown flight on the I284, this will lead to either the J350 or J275 in 54mm. Hope someone shows up with the necessary items tomorrow....

Iter, good luck with your certification-- that's a very sturdy looking glider if I ever saw one. BTW, how much do the electronics weigh? For that matter, how much does the whole thing weigh?

Click to expand...

...

Mike--I wonder if you have any photos of your gliders. Sometimes the simpler design is the better one. I keep feeling that I'm overcomplicating things with Vulcan.

I'm curious also about your choice of J350 and J275. Every time I think about L2 gliders, I think about a long-burn J90.

Ari.

That's pretty cool.

Working on the wings.

I cut 1" off the trailing edge of both wings.

I build servo bays out of 1/4" and 3/32" balsa. There are two servos per wing--mostly for redundancy in case one of the surfaces, pushrods, servos or links breaks. With a 2-servo elevon wing, any one of these is a critical path as my experience with my smaller RCRGs teaches me. I might set up the inboard servos as flaps and outboards as elevons. In this case, I might make the inboards wider but set them up with less travel. Still working out the details.

I carve cavities for servo trays into the foam. On Sunday, Leah asks to see how the glider is doing (it's mostly too technical and boring for her) and says she wants to help me. She has a much easier time pulling little bits of foam from the cavities than I do.

Routing servo wires occupies me for a while. Eventually I decide to route them separately and drill the cores roughly along the paths that wires show in the photo. That is a 25" drill bit--I finally have a use for it! Drilling such a long, blind hole is tricky. The first one almost breaks though on the underside of the wing. The last one comes out exactly in the corner of the servo cavity. Amazing what a little experience does. Feels like a waste that I'm only building one of these :=)

After drilling the holes, I glue in the servo boxes. I use white Gorilla glue. It foams up as it cures and expands to fill gaps in the foam. It has a tendency to ooze out of every seam. I use masking tape to contain it. The tape acts as a sort of mold and creates a smooth surface--in this case, flush with the top of the wing.

Ari.

It sounds like you are going to cover and coat the wings. I assume that this will add some strength. I have a parasite glider on my 4x Orbital Transport that has foam wings. Several times the wings have broken. On some of those occasions the wing has broken on ascent. On the latest flight I bonded 1/64" ply to both sides the wings and the wings did not break. This method added a lot of weight, but it was worth it, if my wings do not break again.

Hi Ari,

Great thread. BTW I know a lot of guys at tomcats, including Bob Parks. I fly turbines myself in Southern California.

I have random questions in no particular order:

How do you plan to hinge the ailerons and flaps? And what do you plan to make the ailerons and flaps out of?

Have you simulated this yet? I would think this configuration could be simulated in open rocket fairly easily. I am curious what you think you will hit in top speed. I wanted to make a giant glider with the same motors you are looking at.

And finally how did you cut your parts? Do you have access to your own laser cutter?

Keep posting it is very interesting!

Aerostadt: plywood sounds quite extreme. I plan on paper and laminating film. The goal is to add not only strength but also protection from scratches and dings--especially relevant on a belly-lander. Vulcan has 8 sq. ft. of wing area. Covering double that (top and bottom) in 1/64" plywood can get expensive :=)

I wonder if you ever got your Arcie back flying.

Matt: Bob Parks got me to simulate this. His original concern was top speed, and I'm glad he convinced me to run simulations. Open Rocket doesn't really know how to deal with airplanes or thick "fins." I'm making some assumptions about approximating drag, such as taking the frontal cross-section of my wing and making a round rocket with equivalent cross-section area. Mass however--not drag--seems to be the key in keeping speeds down. My goal is to keep the speed under 130 mph on the way up. My thought process for giant gliders (starting with Vulcan) is this: get a mass that results in a top speed I can handle on the way up, then get enough wing area to get the speed in a range I can handle on the way down. I expect that you're much more comfortable than me with high-speed flying, what with your turbines and all.

I plan to use Sig CA hinges. The ailerons and flaps are balsa, perhaps with NS reinforcement.

I use the laser cutter at Sawdust Shop (https://sawdustshop.com/). They have all kinds of woodworking tools. I recommend this place wholeheartedly.

Ari.

Ari,

I have used Great Planes 3/4" x 1" CA hinges on my 4x OT glider and it has worked for my flight loads. They have pulled out on hard landing loads, but are fairly easy to reinstall. My elevons are 1/2" foam, but framed with something like 1/4" x 1/2" aircraft wood, which might be overkill for your application. If your plane can withstand 130 mph model airplane flights, then similar rocket flight speeds should make no difference. I have not gotten around to flying the Arcie, yet.

I did use 20 pound paper glued on both sides with white glue to balsa wings on my Double Shuttle this past year and it worked flawlessly with two clustered Estes BP E-motors.

Well, this is the point of no return. I join the wing halves. Whatever warps are in there are there to stay.

First photo shows a servo bay with the glue filling gaps quite nicely.

I need unusually long servo wire runs on this model. My first idea is to use long extensions, but they prove hard to snake into my wing wire tunnels. I cut connectors off the servos and solder on 22ga 3-conductr wire. Heavier gauge might reduce losses due to length. I make somewhat crude holes in the BT to let wires in.

I cut a slot for the fin assembly out of the top of the wing halves and dry-fit everything, including wires. I want the servos to be removable in case I need to replace one, but it's a lot easier to snake the wires in while I still have access to the BT.

Well, this is it. The glue is curing on possibly the most significant glue line of this build.

Ari.

Pretty neat to see how you are working with the foam. I have no experience with foam of this type or RC for that matter. I will watch and learn.

How much do the servos weight?

cwbullet said:

How much do the servos weight?

Click to expand...

HS-82MG are 19g a pop, plus the weight of the extra extensions.

kj

iter said:

Matt: Bob Parks got me to simulate this. His original concern was top speed, and I'm glad he convinced me to run simulations. Open Rocket doesn't really know how to deal with airplanes or thick "fins." I'm making some assumptions about approximating drag, such as taking the frontal cross-section of my wing and making a round rocket with equivalent cross-section area. Mass however--not drag--seems to be the key in keeping speeds down. My goal is to keep the speed under 130 mph on the way up. My thought process for giant gliders (starting with Vulcan) is this: get a mass that results in a top speed I can handle on the way up, then get enough wing area to get the speed in a range I can handle on the way down. I expect that you're much more comfortable than me with high-speed flying, what with your turbines and all.

I plan to use Sig CA hinges. The ailerons and flaps are balsa, perhaps with NS reinforcement.

I use the laser cutter at Sawdust Shop (https://sawdustshop.com/). They have all kinds of woodworking tools. I recommend this place wholeheartedly.

Ari.

Click to expand...

Hi Ari,

Well you have in my opinion one of the best guys in the world helping with this (Bob). That was my concern, very high speed. In my experience, 130 mph is not that high, and the flutter resistance of those relatively thin trailing edge devices is helped by the fact that they are shorter (because you have 4 of them) and you are driving them near their center. I think you will be more than fine at 130. I would start to worry at 180 to 200+.

Even though I fly turbines, they don't accelerate like these rockets!! I found that setting a trim onto the throttle stick was helpful on launch, full throttle is nose down trim. And remember the mass helps slow you down most when going vertical, you need to keep it going straight up until you know the speed characteristics on these long burn motors (don't ask me how I know!)

Boy between the TechShop and the Sawdust shop you bay area guys have it made <<insert jealous smilie here>>

BTW I assume that Flying Foam was able to cut the root profile (the fore/aft profile that hugs the body tube) as well? I have never seen that done, very slick.

You have a nice kit in the making if this thing flies well!

mr_matt_II said:

BTW I assume that Flying Foam was able to cut the root profile (the fore/aft profile that hugs the body tube) as well? I have never seen that done, very slick.

You have a nice kit in the making if this thing flies well!

Click to expand...

Yes, the foam in its entirety is Coby's work. This is a more complex cut than most of his work--it requires re aligning the foam between the two passes. The wonderful lines at the front and rear are simply the intersections of the airfoil and the cylindrical BT form. I recoil in horror at the thought of having to lay out these lines by hand :=)

Ari.

mr_matt_II said:

Even though I fly turbines, they don't accelerate like these rockets!! I found that setting a trim onto the throttle stick was helpful on launch, full throttle is nose down trim.

Click to expand...

This is what I do now. Glider pilots often set up the throttle stick to control the flap channel. This is how I treat it on my RCRGs: forward throttle stick is zero lift. It's consistent with how I think of all stick inputs--push to go faster, pull to slow down. I usually let my gliders fly themselves vertically on the way up, then as they start to nose over, I start easing back on the throttle (flap/elevarot trim) stick. Also, my ignition controller is a brushed ESC that I plug into the throttle channel on a separate receiver on the ground. Now that I have this setup, I can only launch when the throttle stick is in the zero-lift configuration. This is experience talking. Taking off with glide trim produces very exciting inside loops right off the pad. My setup helps me avoid that.

Ari.

I pull the tapes off and weigh the wing. As it is in the photos--without covering, fin, motor, nosecone, RX, battery and probably a metric ton of nose weight--it clocks in at 954g. The 1,500g dream weight seems unlikely now. On the flip side, the higher mass is going to slow it down on the way up and make it easier to control.

Ari.

Ideas for trim scheme--flames on top, checkers on bottom.

Ari.