Summer Buildoff: Roc n Roll Flying V guitar

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I wasn't totally sure what this build was going to be when it started, but now that it's really taking shape... awesome. Just the fact that it'll fly with two fins makes it a winner, but now I'm really spoiling to see what the finished product is going to look like.

Too dang many good builds going on right now, there's gonna be some kind of hangover in the fall when the contest is over.
 
Looks like you're strumming along!

Of course the builder is definitely showing some pluck!

Which gives me an idea for a name for this... "What the Pluck?!"
 
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The bottom, curved main portion of the neck is being sheeted in two halves. I took a 1/16 balsa sheet, wetted it with water, and let it dry while taped in a curved position. As you can see here, the first half is being held in place while I get the second half cut to size. Thankfully 3M 77 sets up very quickly.

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For the parachute, may I suggest 4 chords?

Some language might not be suitable for younger members

[video=youtube;Co9mW_9hH2g]https://www.youtube.com/watch?v=Co9mW_9hH2g[/video]
 
Detail work. I cut two 1/8" ply plates; one to cap the front of the body and one to cap the aft end of the neck. The one on the neck really helps reinforce the joint between the BT-55 coupler and the foam. Also a couple shots of how the rocket is looking now, including a semi-profile view showing how much base drag will be generated from the body.

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Man, that's looking really good! How do you intend to finish it? I was thinking a nice red metallic Monokote would look nice on the body and head, with a black or graphite neck.
 
Now we need someone to do a flying cowbell cause you always need more cowbell:) that Guitar sheeting looks excellent! Based on mindsim, the base drag idea seems like it should work given the width of the guitar body..

Frank
 
I was really wanting to do Monokote, but I am a little concerned about the weight and may have to just use paint. I have a launch this weekend and should have it ready for a test flight then. Based on how it performs, I can decide on finishing materials. Of course it could be a total failure and there won't be a need to pick up finishing supplies - we'll see.
 
I wasn't totally sure what this build was going to be when it started, but now that it's really taking shape... awesome. Just the fact that it'll fly with two fins makes it a winner, but now I'm really spoiling to see what the finished product is going to look like.

Too dang many good builds going on right now, there's gonna be some kind of hangover in the fall when the contest is over.

I have read the Apogee Newsletter that says two finned rockets are dynamically unstable, so how can this work?. You don't see anyone flying 2FNC! At least the fins and motor are in the right place for this one. Not like those crazy guys with two fins way up front along with the motors.

https://www.apogeerockets.com/Peak-of-Flight?pof_list=archives
 
Combining the best of Model Rocketry and Luthiering...Awesome job!
Would be neat if you could actually get a working pick-up and strings attached to this thing -

WHOOSH...POP...GARAGE JAM.....
 
Just have a couple more small sheets to add to the head and neck, then it's all done. I added the launch lugs and eyebolt, just need to add a shock cord and parachute. I balanced the rocket with a D12-3, and it came in just a little under 3" behind the break. So I tied a string 3" behind the break so the rocket could rotate in the yaw axis and took it outside for a swing test. I've never done a swing test before so I didn't know what to expect. Well after getting some speed and letting the line out a ways, the rocket stabilized with very little wiggle in the yaw axis! So, all is looking good for a test launch at my club launch on Saturday. I'm not sure if I'm going to be able to get to our August launch and was hoping to at least get a basic finish on the rocket before this weekend, but it doesn't look like that's going to happen. I could probably do it in Monokote by then, but having the time to make it happen might be tough. Besides, I don't really want to spend 40 dollars on covering just to find out the rocket doesn't fly. So, test launch naked first, then make it look pretty. Pretty pumped to see how it goes on Saturday.
 
All shaping, sheeting, and sanding is complete. The rocket measures 36.5" long with a 14.125" fin span. Weight without motor is 8.6oz. All is set for a test launch or two on Saturday. According to the swing test it'll fly, but I am still full of anticipation.

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Just too cool.

Are you going to paint-on a fret board and strings?
 
How do you intend to finish it? I was thinking a nice red metallic Monokote would look nice on the body and head, with a black or graphite neck.

I was really wanting to do Monokote, but I am a little concerned about the weight and may have to just use paint...
I was thinking a classic sunburst like these would be cool:
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Or just a simple blond stain. In either case, remember that balsa absolutely needs a pretreatment such as this before any staining.
 
I too vote to keep the wood grain finish. It is a guitar for cryin' out loud! What do folks think this is?. . . Some sort of flying model rocket? Look, he isn't going to play it, he is going to fly it!
 
I was really wanting to do Monokote, but I am a little concerned about the weight and may have to just use paint. I have a launch this weekend and should have it ready for a test flight then.

I was wondering if we might see it tomorrow. Cool!

What size launch rod will you need?
 
I have read the Apogee Newsletter that says two finned rockets are dynamically unstable, so how can this work?. You don't see anyone flying 2FNC! At least the fins and motor are in the right place for this one. Not like those crazy guys with two fins way up front along with the motors.

https://www.apogeerockets.com/Peak-of-Flight?pof_list=archives
I'll see your PoF article, and raise you two others. (Actually, it's a two parter.) The idea with the Flying V is base drag stability. It's explained, along with how to simulate it, in a pair of articles in issues 154 and 158. (Of course, that's simulating round rockets with lots of base drag, so no help here.)

The tricky bit, that part that bothers my mind sim, is that if there's enough base drag to make it stable in the yaw direction, those two giant fins are liable to make it radically overstable in the pitch direction. But my mind sim is way less experienced than lots of other people's, so you probably shouldn't listen to me.
 
Yeah, base drag is yer friend. I have no fear on this one. Fear is the mind killer! In calm conditions I would stand up and watch this one launched, no problem. Knees bent, moving side to side during the count down, having scoped out a ditch or some good cover close by. Keeping my eyes on the prize and making sure my bowels have been recently emptied, just in case. Yeah, no fear, confidence is key! Trust in thrust and lots of lovely, wonderful nose weight. There is going to be a big delta shining in the sky, like a national guitar!
 
I was wondering if we might see it tomorrow. Cool!

What size launch rod will you need?

Just a 3/16 rod for this one. Hoping to do a lob on a D12-3, so if it ends up impaling a cub scout or CAP cadet it shouldn't go all the way through :) .
 
OK..... The CAP kids have a couple of things they fly off of 3/16 as well (me, too) so I'll be sure to have plenty available. I just needed to know in advance if you needed 1/4 since I usually don't bring one of those.

See you tomorrow.
 
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I would go 6' quarter inch. Lifting 10 oz, is OK but lot's of drag to get up to speed. But then again I have to fly under supervision who is extremely critical of any hint of rod whip or slow speed off the rod.
 
An E20-4 is planned, pending a successful test flight. Wimpy is good for a test on a design like this.
 
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I think wimpy is OK for decent 4fnc, but not necessarily silly odd rocs. It might be better with more power and balance up front. But who am I to question the long held validity of first flights on lowest motor possible. If a D12 off a shorter rod is good, go for it! Maybe more power and nose weight is just a crutch.
 
I'm not sure why you're going on about nose weight. It already has nose weight and has been balanced and test swung already. The reason I want a wimpy motor is because 1) the rocket has proven to be stable at low speed through my backyard tosses and swing tests, and 2) if it does happen to go wonky, I don't want it pointed at a cub scout while under composite motor power.
 
[video=youtube;a1hZjhQ9Ps0]https://www.youtube.com/watch?v=a1hZjhQ9Ps0[/video]
 
Well done, sir! I admit I had my doubts, but you certainly showed me who knows what he's doing. Hats off. (Once again I ask, why is there no imoji for that?)
 
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