12" Talon on a P

GiachiG aka Typico said:

you guys are very funny, your post makes me smile alot

and don't worry about my opinion, mi knowledge costs too much for you.... i'll keep all for wealthy builders

enjoy your risky flights and forget about me

Click to expand...

In all seriousness, we appreciate your concern, but we've used this method before. Last time we flew this rocket, we had no less than three people come tell us the fins would rip off. And they didn't. The downward force of the fins won't be enough to rip the hinge and it's rivets though the airframe, which is made up of thick sonotube and fiberglass. Plus, the fins are butted up to a bulkhead on both sides inside the tube, so even if they did start to rock back, the fins would have to literally disintegrate before coming loose.

In short, while we know it ain't pretty, we also know the fins are as stong as can be while meeting both objectives of keeping the thing light enough to fly in CA and allowing the fins to be removed for storage purposes.

GiachiG aka Typico said:

you guys are very funny, your post makes me smile alot

and don't worry about my opinion, mi knowledge costs too much for you.... i'll keep all for wealthy builders

enjoy your risky flights and forget about me

Click to expand...

Besides.. If something does happen and the fins rip off, just remember- Cool guys don't look at explosions:

[youtube]Sqz5dbs5zmo[/youtube]

SpartaChris said:

In all seriousness, we appreciate your concern, but we've used this method before. Last time we flew this rocket, we had no less than three people come tell us the fins would rip off. And they didn't. The downward force of the fins won't be enough to rip the hinge and it's rivets though the airframe, which is made up of thick sonotube and fiberglass. Plus, the fins are butted up to a bulkhead on both sides inside the tube, so even if they did start to rock back, the fins would have to literally disintegrate before coming loose.

In short, while we know it ain't pretty, we also know the fins are as stong as can be while meeting both objectives of keeping the thing light enough to fly in CA and allowing the fins to be removed for storage purposes.

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I can't resist asking, why not just bolt on aluminum angle instead of the piano hinge? It would be stiffer, lighter, and you have to unbolt it to get the fins off either way, right?

Adrian A said:

I can't resist asking, why not just bolt on aluminum angle instead of the piano hinge? It would be stiffer, lighter, and you have to unbolt it to get the fins off either way, right?

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Truth is I don't know that we thought of using angle iron. The piano hinge worked great the last time, so we didn't feel the need to change it this time. It's certainly an interesting idea though, one that could be explored for future rockets.

One benefit to the piano hinge right off the top of my head is once the fins are removed, we can fold it down and avoid the possibility of cutting ourselves or damaging anything when the airframe is loaded. Can't really do that with the angle iron, unless we were to make it removable as well.

It is an interesting thought though. Maybe Charlie can chime in as to why we went one way over the other.

Adrian A said:

I can't resist asking, why not just bolt on aluminum angle instead of the piano hinge? It would be stiffer, lighter, and you have to unbolt it to get the fins off either way, right?

Click to expand...

Ok, I just got off the phone with DJ SpeedyWeez, and he jogged my memory. I now remember the conversation like it was yesterday.. Or was that today.. Hell, I dunno.

Anyway, we explored the possibility of using the angle iron with our initial build. The problem is you have a 90 degree object trying to rest flat on a cylinder. When you pop the fin into the slot and put the angle iron in place next to the slot, there would be a gap on both sides. Take a look at this pic:



The black represents the airframe and the fin. The yellow is how the angle iron would be mounted if it were flush against the fin. Note the gap below where the angle iron isn't flush with the airframe. Since the angle iron would be mounted directly to the airframe, that gap you see would be where it should mount to the fin. Basically, it wouldn't be a flush fit. The piano hinge was the best way to compensate for the angle needed to securely mount the fins.

So that's why we went with the hinge as opposed to angle iron.

SpartaChris said:

Ok, I just got off the phone with DJ SpeedyWeez, and he jogged my memory. I now remember the conversation like it was yesterday.. Or was that today.. Hell, I dunno.

Anyway, we explored the possibility of using the angle iron with our initial build. The problem is you have a 90 degree object trying to rest flat on a cylinder. When you pop the fin into the slot and put the angle iron in place next to the slot, there would be a gap on both sides. Take a look at this pic:

The black represents the airframe and the fin. The yellow is how the angle iron would be mounted if it were flush against the fin. Note the gap below where the angle iron isn't flush with the airframe. Since the angle iron would be mounted directly to the airframe, that gap you see would be where it should mount to the fin. Basically, it wouldn't be a flush fit. The piano hinge was the best way to compensate for the angle needed to securely mount the fins.

So that's why we went with the hinge as opposed to angle iron.

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Yeah, that makes sense. And since you guys only have a 5" diameter airframe, I can see how that's a problem. Ever think about making one a bit bigger?

I love the thread, by the way. That progression of ugly was classic. And yes, I agree the piano hinge will do its job just fine, since the slots are doing the hard part of holding the fins on.

Thanks for the kind words, I'm glad to hear folks are enjoying the thread. The project really is a lot of fun to work on, especially with the cast of characters we have. Well, not so much our resident n00b, but everyone else is cool.

J/playin James.


As for a bigger one, we'll build it if you sponsor it! :cyclops:

Adrian A said:

And since you guys only have a 5" diameter airframe, I can see how that's a problem. Ever think about making one a bit bigger?

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This is a 12" airframe, hence the name.

SpartaChris said:

In all seriousness, we appreciate your concern, but we've used this method before. Last time we flew this rocket, we had no less than three people come tell us the fins would rip off. And they didn't. The downward force of the fins won't be enough to rip the hinge and it's rivets though the airframe, which is made up of thick sonotube and fiberglass. Plus, the fins are butted up to a bulkhead on both sides inside the tube, so even if they did start to rock back, the fins would have to literally disintegrate before coming loose.

In short, while we know it ain't pretty, we also know the fins are as stong as can be while meeting both objectives of keeping the thing light enough to fly in CA and allowing the fins to be removed for storage purposes.

Click to expand...

understood..
but it's not the downward force that makes me doubful, what can't convince me is how they beheave with vibrations(flutter or wathever may occour)
it's strange to see a P motored rocket using this solution... even the use of mat is not what everyone will do(not always what everyone do is right, i know)

BUT.... the video you posted rocks!!! ahahahahhahah it's hilarious!!!!!

tell something about my project if you have time

bye

(humor attempt)--->whoosh-->
...............................

.

GiachiG aka Typico said:

understood..
but it's not the downward force that makes me doubful, what can't convince me is how they beheave with vibrations(flutter or wathever may occour)
it's strange to see a P motored rocket using this solution... even the use of mat is not what everyone will do(not always what everyone do is right, i know)

BUT.... the video you posted rocks!!! ahahahahhahah it's hilarious!!!!!

tell something about my project if you have time

bye

Click to expand...

The fins are gonna flutter a bit, sure, but the channel mounted to the inside tube will keep the fins secured in place. In order to mount the fins, they'll have to be firmly seated to the bottom of that channel. The channel extends like 2" up along either side of that fin, so if they become unseated, we're probably experiencing a much bigger problem than the fins.

Have a link to your project?

Because a project like this doesn't come cheap, it's with a tremendous amount of gratitude that we say thanks to our sponsors.

First we'd like to thank Greg and Aaron from Ecology Auto Parts, The Original Serve Yourself Wrecking Yard:



Visit their website, www.ecoparts.com for more details and information.

Next we'd like to thank Jeff and Eric at Trading Addicts:



If you're looking for a top notch investor education, Trading Addicts is by far the best place to go. Visit them at www.tradingaddicts.com. Tell them SpartaChris sent you.

This project would be a lot harder to accomplish without your help, so again, thank you very much!

yes of course, is in this forum, the SpeedWeiser project

https://www.rocketryforum.com/showthread.php?t=2856

it's an upscaled Budweiser bottle
weight and dimension... 94" and 55lb

enough for any kind of thirst
it will flight mostly with K thru L motors but i can use a cluster of one central M and four 54mm moonburners(K250) to reach 13-14Kft

GiachiG aka Typico said:

yes of course, is in this forum, the SpeedWeiser project

https://www.rocketryforum.com/showthread.php?t=2856

it's an upscaled Budweiser bottle
weight and dimension... 94" and 55lb

enough for any kind of thirst
it will flight mostly with K thru L motors but i can use a cluster of one central M and four 54mm moonburners(K250) to reach 13-14Kft

Click to expand...

Oh yeah, I did see that when I was browsing. It's a very cool project, but there's only one problem with it. It's a problem so big that unless you fix it, your rocket is destined for despair each and every time it flies:

You're not using a Fat Tire bottle:



Fat Tire- The beer of Gods amongst men. And stuff.

Very cool project!

I guess marketing on the 6oz shorties didn't quite work out?

We do have a lot of fun with this thing. Why, we didn't even consume a single beer yesterday during our build session... It's like we just enjoy what we're doing even without the Fat Tire. (We just enjoy it more WITH Fat Tire.)

@ our Italian contributor --> Chris' point about the piano hinge is solid. There will be no flutter in these fins. Flutter in general is the result of aerodynamic forces inducing vibrations into the fin material which, when a harmonic frequency is reached, causes fins to flutter -- often to a point of failure.

While we often dumb down our explanations because the technical jingo just isn't funny and we like to abbreviate our absurd names for things like CGDCF (Charlie's G!D! Composite Fins), remember this: the construction principles here are sound. You see, the fins are neither a single material nor a single layer. They are five-layer composite fins consisting of fiberglass (I take exception to your notion that foam & glass is anything but a standard in sport rocketry), foam, plywood, foam and fiberglass. As your sophisticated construction methods are apparently reserved for wealthy Mediterranean builders, I'm sure you're well aware that such a construction not only helps to ensure that a harmonic vibration as outlined above is never achieved -- especially in a subsonic flight regime -- but that each of the multiple layers & materials actually serve to dampen harmonics within other layers.

I'm fairly certain we'll make it just fine. If not, it won't be due to our fin construction and I'm pretty sure it won't be due to our fin mounting methods, either.

/removes tongue from cheek

speedyweasel said:

I'm fairly certain we'll make it just fine. If not, it won't be due to our fin construction and I'm pretty sure it won't be due to our fin mounting methods, either.

/removes tongue from cheek

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Hey, things could always get worse:

Always quick with a warm and helpful thought.

While the rest of the country is off at LDRS having what I hope will be a great time, I figured I would use this time to do an update on It Burns When I P.

I wanted to start by paying homage to the unsung hero of Project Talon. Our hero has been with us since before Talon one. He's been used and abused without complaint and has graciously stuck by us as we embarked on this latest endeavor.

So it's with out sincerest gratitude we say thanks, Mr. Rocket Trailer of Demise, for without you we'd never get our rockets safely to the launch:



And because you're such a trooper, the HBWOTA found it prudent to provide you with an upgrade- A bottle opener!



So thanks for all your service. It is much appreciated!

As you recall from last update, we ran into a bit of a problem when we put our fins under vacuum. Learning from our mistakes, we decided to compensate for the raw power of Tim's Mystery Device of Doom by making each fin a bit thicker:



We expect each fin to be normal thickness once the vacuuming is done.

Some other things we did different this time around- For starters, we made sure Joe had some peel ply covering him up so we could un-stick him:





We also made sure to draw the vacuum a bit slower this time, so as to ensure we didn't peel the glass or foam off the edges:



By the way, anyone wanting to build a California Raisin themed rocket is welcome to these fins:

With the fins set aside to cure, we began the process of trimming and fitting CGDBT. The first step was to cut off a piece of sonotube to make this step a bit more manageable:



The piece we'll be using to fit the shoulder of CGDBT to the rocket:



Next, Charlie marked a couple of reference points on the tube to indicate where the half way point was. This will aid us in trimming any excess from the sides of the boat tail cone parts:



With the reference points marked, we did a test fit of one of the halves to the tube, and using the marks on the tube as a reference, made a mark on the part. We extended that mark along the entire length of the part using a chalk line:



Everything below, and including the chalk line will be cut:

Now it's time to gear up. Here's Joe and I preparing for our upcoming roles in the latest slasher film called "Flaming Rockets of Fire and Death and Carnage and Stuff," Due out in October. It's sure to be an Oscar winner, so check local listings for show times:



Since Charlie did the last bit of cutting, Broseph opted to give him a break and take over the trimming of the boat tail cone. Go BRO!



Chants of "BROSEPH, BROSEPH, BROSEPH" could be hear ringing through the neighborhood as he made the final cuts:



That Broseph, he's so hot right now. He's a real American Hero!

Now that the trimming is done, it's time to test fit the two halves into the tube mold thingie and see if any more trimming needs to be done. Unfortunately the parts came out a bit flat, so to make sure we got the proper contour and shape, we used a clamp to squeeze it together:



Charlie takes a moment to make himself a snack:



Kids, don't do drugs:

The two halves in the mold. We noticed both parts are a bit flatter than we would have liked:



But some quick thinking brought us to our boat tail cone part squeezer together jig. It'll be for sale through our website soon, so be on the look out for it:



Kids, remember what I said about not doing drugs? Yeah, it's because this happens. Here's Charlie, looking normal:



Or maybe like Condor Man. Could it be?

After we confiscated Charlie's "Wings", we put the two halves together again and secured the seams with Chuck Norris approved power bonding fabric of death:



Even wrapped a little around the boat tail cone for good measure:





Since we had to re-do the fins, that's all we had time for this session. With the day coming to a close, and James needing to high tail it home, he gives us a quick goodbye:



And he's off! Bye James!



Stay tuned, more to come..

Wanted to give a huge thanks to Mark at StickerShock23.com for stepping up as a sponsor!



We greatly appreciate everyone who's coming through for us to help us with this project. Thanks again for your support!

Figured this was suited for a 4th of July update. Last weekend I was able to pick up the motor casings from David Reese. Wow I forgot just how huge these things were!

On the right is the casing we used for the O motor last time we flew this. It stands at 38" long. On the left is the P casing for this upcoming flight, standing at 52" long:



And of course, what build thread would be complete without the obligatory hot chick posing with the motor casing shot?:



More to come..

SpartaChris said:

Figured this was suited for a 4th of July update. Last weekend I was able to pick up the motor casings from David Reese. Wow I forgot just how huge these things were!

On the right is the casing we used for the O motor last time we flew this. It stands at 38" long. On the left is the P casing for this upcoming flight, standing at 52" long:

And of course, what build thread would be complete without the obligatory hot chick posing with the motor casing shot?:

More to come..

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SpartaChris,

Is the motor case custom made? if so, where did you get it made from?

BB-ROCK

BB-ROCK-

If I told ya, I'd have to kill ya. :cyclops:

The casings were made by TDK Propulsion. https://www.tdkpropulsion.com/

SpartaChris said:

BB-ROCK-

If I told ya, I'd have to kill ya. :cyclops:

The casings were made by TDK Propulsion. https://www.tdkpropulsion.com/

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Thanks... I won't tell a soul.