Fliplock build, J&H Aerospace kit

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I’ve been looking forward to this model since I first saw it on YouTube. Having built the Switchblade S, another J&H Aerospace model, I was impressed with the clever engineering and out-of-the-box solutions to the now decades old mechanisms for triggering wing deployment and creating rotary hinges that traditional swing-wing gliders still use.

The Fliplock, in addition to being just darned cool looking, attracted my attention because it appears to have what in my opinion is a very innovative wing folding mechanism and deployment apparatus . Hopefully it lives up to expectations and deploys reliably and glides well (by “well”, I mean any glider that has a drop rate at least as good as a paper airplane and is reliable, since I’m a sport flyer and aren’t looking for competition level flight times. I’m easy to please in that respect—but I suspect it just may surprise me and prove quite competitive). I’m in it for the fun, and this is definitely an attention-getter.

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Pics courtesy of J&H Aerospace/Joshua Finn

So enough with the chatter, on with the build.
 
OK, now the kit “unboxing” part. Lots of small parts. That’s not a criticism, it’s only nerve wracking for folks like me with fat finger syndrome that are prone to losing small parts. I’ve had pieces of music wire catapult out of my hands when cutting or holding with tweezers and take impossible-to-follow trajectories somewhere into my model building room. Sometimes I find them months later when they embed themselves in my foot or I step on—and smush them—in some unlikely corner of the room.

BTW, there are no paper build instructions included. Instead there is a very comprehensive HD YouTube build video here: https://youtu.be/B1vOoLpH8MI
I’d suggest viewing it through several times to totally familiarize yourself with the build steps before starting. If you assemble things out of order you could find yourself in quite a bit of trouble.

The kit does come with parts templates though, a nice touch in case you should damage some parts during landings or construction. I appreciate that, as I’m prone to doing both.

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First order of business: installing the swing wing hinge axle. The fuse is a pretty complex laser-cut shape. Be extra careful not to damage it, since it’s something very difficult to duplicate with a hobby knife if you mess up. I’m also taking the precaution of keeping everything in a plastic bin and occasionally assembling any tiny parts inside as I don’t want to lose or misplace any of them. (That’s a likely situation since I tend to work on more than one model project at a time).

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Next come the plywood doublers to reinforce the forward end of the fuse and lock the hinge wire in place. I had to carefully run my hobby knife along the compound curve edges to release the doublers because I didn’t want to damage them by just bending the carrier sheet around it. Just my own personal preference, if you have nimble fingers proceed as you wish.

When gluing these pieces on, make sure the slots and holes in it match up exactly with the corresponding openings on the fuse.

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Just a little tip when working with CA: rub a small amount of petroleum jelly into your fingers. A thin layer is all you need (and not to the point of being greasy). It’ll keep your fingers from instantly bonding to what you’re working on if you get CA on them and give you enough time to wipe it off. Learned that the hard way. After losing far too much skin on builds I switched to using nitrile gloves. Guess what? Nitrile gloves stick just as tight and after far too many pieces having to be sanded off, I realized that a tenacious waterproof skin barrier like petroleum jelly would probably work.
 
Eric,

Thanks for doing a build thread on this. It's definitely the most difficult model I've yet designed, not from a complexity standpoint, but rather from making it work. I lost count of how many times I had prototypes come apart before even leaving the launch rod, let alone those that came apart in flight. Ironically the first prototype functioned flawlessly other than catching on fire on the second or third flight when the wings dried and warmed enough for bits of expelled fuel to ignite the upper wing (flew fine the whole time it was burning :wink:).

Anyway, I released the kit after finally getting through all that nonsense. Hopefully it'll serve you as well as mine has served me (well, did, until it spend a rainy night in a tree and the wings warped).

-Josh
 
Very cool build. Yes, the other night I had the 'dropsies' while working on my Switchblade-XL.

So, this is a NON-RC model, correct? And does the Fliplock use the same wing mechanism as the Swingshot?
 
Eric,

Thanks for doing a build thread on this. It's definitely the most difficult model I've yet designed, not from a complexity standpoint, but rather from making it work. I lost count of how many times I had prototypes come apart before even leaving the launch rod, let alone those that came apart in flight. Ironically the first prototype functioned flawlessly other than catching on fire on the second or third flight when the wings dried and warmed enough for bits of expelled fuel to ignite the upper wing (flew fine the whole time it was burning :wink:).

Anyway, I released the kit after finally getting through all that nonsense. Hopefully it'll serve you as well as mine has served me (well, did, until it spend a rainy night in a tree and the wings warped).

-Josh

Who doesn't want to be the 1st kid on the block with the newest hippest gadget? Seriously though, you must have mad engineering skills. Don't know how you come up with these intriguing, outside-the-box solutions that also look so cool. Looking forward to trimming and maidening it once the weather decides to cooperate.
 
Very cool build. Yes, the other night I had the 'dropsies' while working on my Switchblade-XL.

So, this is a NON-RC model, correct? And does the Fliplock use the same wing mechanism as the Swingshot?


Thanks, it's a fun build, especially because I couldn't quite wrap my head around how things worked until I actually began to assemble stuff, like finally getting the idea of the whole picture as you piece together a jigsaw puzzle. Yup, it's non-RC and uses just a single hinge for both wings. The Swinshot uses kevlar thread to keep the wings in launch position whereas the Fliplock uses a trigger wire to lock things in position.


As a 2nd year BAR I've come up to speed (almost) by downloading tons of build plans/templates and old publications and I've never seen this technique used before. The design is a definite attention-getter too.
 
Thanks, it's a fun build, especially because I couldn't quite wrap my head around how things worked until I actually began to assemble stuff, like finally getting the idea of the whole picture as you piece together a jigsaw puzzle. Yup, it's non-RC and uses just a single hinge for both wings. The Swinshot uses kevlar thread to keep the wings in launch position whereas the Fliplock uses a trigger wire to lock things in position.

Slight correction: Switchblade uses kevlar; Swingshot uses the same trigger mechanism as Fliplock except with hinged outer wing panels. Confused about names yet? Even I get them mixed up on occasion and I'm the guy that named them! :blush:

As a 2nd year BAR I've come up to speed (almost) by downloading tons of build plans/templates and old publications and I've never seen this technique used before. The design is a definite attention-getter too.

Yeah, I'm pretty sure the overall compilation of Fliplock is completely unique, but then the idea was to solve the problem using the shortest path to goal possible: on hinge, one trigger. Not an easy task on a free flight model. I reverted back to three hinges on the Swingshot (center pivot, hinged outer panels).
 
Slight correction: Switchblade uses kevlar; Swingshot uses the same trigger mechanism as Fliplock except with hinged outer wing panels. Confused about names yet? Even I get them mixed up on occasion and I'm the guy that named them! :blush:



Yeah, I'm pretty sure the overall compilation of Fliplock is completely unique, but then the idea was to solve the problem using the shortest path to goal possible: on hinge, one trigger. Not an easy task on a free flight model. I reverted back to three hinges on the Swingshot (center pivot, hinged outer panels).


Oops...I stand corrected. Must've had an A.D.D. moment, I thought Maxout was referring to his Switchblade XP but I know see he said Swingshot.
 
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Didn't have as much time as I hoped for today.
Got the engine pod in place along with a generous fillet. Carefully installed the Guide Tube (on the right side of the glider) that the Trigger Wire will be threaded through. Because it’s nestled against the engine pod it’s easy to ensure it’s straight. Since the Trigger Wire locks the wings in boost position and releases it when the ejection charge blows the nose cone forward at apogee, any binding here would be a disaster.

The Trigger Wire will butt up against the Wing Lock Guides (again on the right side of the glider), which go into the conveniently provided slots.

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Insert the Trigger Wire into the Guide Tube until it bottoms out against the Wing Lock Guides. Insert the nose cone and bend the Wire at a right angle toward the nose cone centerline. Note that because the Trigger Wire falls near the bottom of the nose cone, you have to angle your bend “upward” slightly (see the two pics). Yes, I made the mistake of initially just bending it at a 90° angle as in the first pic, but that way it wasn’t buried securely in the nose cone and could split the lower section of cone away at ejection. Once embedded , the Trigger Wire is wrapped with the Kevlar thread provided and coated with CA to lock it securely into the nose cone.

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Per the YouTube build video, heed the warning to coat the nose cone base and shoulder liberally with CA. I have other gliders where the nose cone got really char broiled by the over-zealous ejection charge and one actually disintegrated after several flights because I didn’t know to do this. Oh, and sand the shoulder after to make sure the NC slides in and out easily.
 
Here’s the setup as it should be. A bending template is thoughtfully provided to give you an idea of approximately where the bends will end up being located. Since each build will differ slightly, adjust to fit your situation.

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I opted to go with a 3/16” launch lug instead of the stock 1/8” because the thickness of the Kevlar wrap on the aft end of the nose cone looks like it would make for a somewhat snug launch rod fit. Also I’ve had other gliders hang up on the launch rod more than once before. At least a CATO is spectacularly impressive; a rocket hung up and fizzling on the pad impotently is just plain, well…embarrassing.


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Stab and rudder went on today. If you’ve been paying close attention to the build video you already know that the small slot in the stab should be on the right side of the fuselage boom. The wing hold down piece goes here. The rudder gets mounted to the left side below the stab.

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I masked off each wing at the 50% chord location and sanded in an airfoil (make sure you sand on the top side of each wing; it’s marked either “L” or “R”—if the letter appears reversed you have the wing upside down). You don’t need to sand the area beyond the dihedral indicator on the wing root side. Once the trailing edge was done I lightly sanded down the leading edge from the ¼ point on the chord forward, then rounded all the edges.

Hopefully you can make out from the 2nd pic how the wings get thinner toward the TE and tip (highlighted in red). The reason for airfoiling is not only to increase performance, but also to allow flexibility so the wings can bend. This is because the tips will need to be tucked into the hold down piece previously installed on the stab so the glider will boost straight.

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I lightly scored the right and left wings on the thoughtfully pre-marked dihedral line with a razor knife and carefully bent them upward, supporting it with the dihedral gauge that comes with the kit (I klutz-proofed the gauge by gluing it to a piece of scrap so it would stay upright and support the wing at the correct angle while the CA I put in the joint dried).

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Each wing then got a light sanding at the dihedral joint to remove the excess CA and balsa dust crud that squeezed out.

Note that the dihedral break location differs on each wing because they need to overlap.

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The Wing Doublers were then installed on the bottom root edge of each wing. Again they’re conveniently marked so the correct one goes on each wing. In addition to adding strength and reinforcement to this area, they’re also a vital part of the swing wing mechanism.

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Glued the Wing Bearing into the left wing and set it with some kicker. The Bearing's shaft then goes through the hole in the right wing and the hinge Axle Wire is then inserted through the wing/Bearing assembly. Forgot to snap a pic but so far everything is going smoothly.

The Wing Retainer, a small aluminum tube, goes over the Axle Wire and the wire is then bent 90° to lock the hinge into place.
But of course I spoke too soon—minor calamity when there was a space between the top of the Axle Wire bend and tube after bending it and the wings ended up too sloppy loose. Ended up having to cut off the bent part.


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Made sure I buttered the top of the Bearing head with petroleum jelly to prevent any CA from getting down into the Bearing shaft then made sure the Retainer tube got a good dose of thick CA inside. Held the wings in folded position while making sure there was no binding, then hit the CA with kicker. Also topped it with a small ball of epoxy putty to make sure nothing comes loose later. Whew, everything seems to be in working order. Wings rotate, things are snug but not too tight.
 
Had to do a bit of sanding on the left wing tip since it was getting hung up on the Wing Hold Down hook.
I’ll fine tune things after I get the elastic band on that deploys the wings.

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The Fliplock tends to be nose heavy. No surprise there; of the dozen gliders I’ve built, all 6 rocket gliders were. Unlike boost gliders that drop the excess weight of the engine and motor pod, RGs have to contend with that excess mass when they transition to glide mode, which is why in my opinion they’re always more challenging to design.

In launch mode with wings locked back by the Trigger Wire and Wing Hold Down.
I opted to use a #16 rubber band to deploy the wings only because I have a bag of several dozen on hand for various helicopter rockets, and it happened to be the right size. I may use the supplied elastic to fashion a slightly larger band since the opening force is a little too—well, assertive for comfort. (I’ve fractured more than one rotor blade stop on my helicopter recovery rockets by using elastic bands that were too short). I want this little gem to last a good long time.


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In glide mode with some permanent marker color to help me find it easier in the balsa-hued crop stubble of the fields I fly in. (Normally the rubber band actuator would be attached to the wing but I was in a hurry to snap a pic and didn't bother).

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Final trimming and its maiden flight will have to wait till the weather gets better. Unfortunately we’re entering hurricane season around here and the rain has kept everything wet for weeks. Will get a timed flight hopefully within the next 2 or 3 weeks.
 
In glide mode with some permanent marker color to help me find it easier in the balsa-hued crop stubble of the fields I fly in. (Normally the rubber band actuator would be attached to the wing but I was in a hurry to snap a pic and didn't bother).

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That's it. I'm stealing that color scheme. That is absolutely awesome!
 
Watching with great interest........:pop::pop::pop: :eyepop:

Thanks Gary, have you had a chance to maiden your Switchblade XP? I'm looking to get into RC on down the road and I'm pretty sure you can double the flight time of my Switchblade S with hands-on control, maybe even 3x or 4x with a good thermal.
 
Thanks Gary, have you had a chance to maiden your Switchblade XP? I'm looking to get into RC on down the road and I'm pretty sure you can double the flight time of my Switchblade S with hands-on control, maybe even 3x or 4x with a good thermal.

Not yet. Hope to maiden the Switchblade in the next day or two, because I hope to take it to S.M.A.L.L.

The Small Model Airplane Lovers' League [SMALL] is an RC airplane fun-fly held in Little Rock, Arkansas, in early June. The only rule is that all the models must use glow motors of less than .25 cui, or any electric of similar power.

Strangely enough, there is a history of RC rocket gliders at SMALL. I hope to do several flights of my rocket gliders.
 
Great build, Eric. Looking forward to some launch pics or video when the weather cooperates.

Thanks, appreciate that. Finally caved and ordered a stopwatch so I can get some accurate flight times. Now if only the weather gods would cooperate...
 
Are you gong to fly the klingon? BTW I just recently came to the brilliant conclusion I can use my radio timer stopwatch setting activated by the throttle position to measure my glide times, don't know why I didn't think of this before....when I flip in my up trim I push the throttle up at the same time....and shut off the throttle when I land.


Not yet. Hope to maiden the Switchblade in the next day or two, because I hope to take it to S.M.A.L.L.

The Small Model Airplane Lovers' League [SMALL] is an RC airplane fun-fly held in Little Rock, Arkansas, in early June. The only rule is that all the models must use glow motors of less than .25 cui, or any electric of similar power.

Strangely enough, there is a history of RC rocket gliders at SMALL. I hope to do several flights of my rocket gliders.
 
Finally had time to trim the Fliplock in the late afternoon when the humidity was low. My honest opinion is that if you get the CG where the build video recommends, you'll be far ahead of the game when it comes to fine tuning things to match the flying conditions of your launch field. I spent all of 5 minutes tossing the plane just to see if I could mess up the smooth floating glide. I ended up not having to adjust anything.

I used an expended A10-3T casing instead of the recommended 1/2A3-2T because that's all I had, and because the A10 might be a tad heavier (and the clay cap is further forward) I may have to fine tune the trim on hot humid days or cold dry winter launches, but my guess is that you won't need to unless you're using it for competition and want to wring out every last second of air time. I'm hoping to fly it next weekend, and it's a good excuse to try out my new stopwatch.
 
It's awesome to hear you're getting closer to a launch. I really want to hear how this one flies for you.
 
It's awesome to hear you're getting closer to a launch. I really want to hear how this one flies for you.

I don't think I'll be disappointed. My Switchblade flew on a 1/2A3-2T and stayed up long enough for me to start getting concerned I'd never get it back.
And the coolness factor of having something that changes shape more than makes up for uber long flight times.
 
Follow up

Maidened it yesterday on a 1/2A3-2T but the motor didn’t have enough oomph to get it much higher than about 40’ (unless the motor malfunctioned?). Fortunately the short delay deployed the wing opening mechanism before it hit the ground but…unfortunately it also ejected the engine (my bad, apparently didn’t use enough tape to friction fit it tight enough) so it wasn’t glide-stable. Was glad to see the wing deployment method worked flawlessly and the only maintenance I’ll have to do is to sand the nose cone shoulder a bit. Seems the heat of the ejection charge swelled it up some.

So a re-do with an A10-3T is planned for next month.
 
Follow up

Maidened the FlipLock yesterday on a 1/2A3-2T but the motor didn’t have enough oomph to get it much higher than about 40’ (unless the motor malfunctioned?). Fortunately the short delay deployed the wing opening mechanism before it hit the ground but…unfortunately it also ejected the engine (my bad, apparently didn’t use enough tape to friction fit it tight enough) so it wasn’t glide-stable. Was glad to see the wing deployment method worked flawlessly and the only maintenance I’ll have to do is to sand the nose cone shoulder a bit. Seems the heat of the ejection charge swelled it up some.

So a re-do with an A10-3T is planned next month.
 
Hmmm.......so, does the model NOT have an engine hook? Can you add one?

Non-engine hook setups have worked badly for me. Either I don't put enough tape on to hold the motor, or I put too much tape on, and I can't get the used motor out without damaging the model. :confused:
 
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