LOC Expediter

Well, I couldn't launch anything today.... But I did buy a LOC Expediter..... I am going to beef it up a little as I am planning on making it a Hybrid Rocket...... A longer motor mount tube and a few extra centering rings are the main upgrade.....

I got it home and looked at all the pieces of the kit...... I quickly noticed that the fins (3 each) come in two pieces.... The main fin and the Fin Tab extension......

I really don't like this idea........ Has anyone else build this kit? I am thinking that I may want to build the fins as one whole piece out of G-10....... What does anyone think???

I plan to take pictures of each of the main steps in construction........

I just used the two pieces as provided. This was the second kit I ever built -- if I were to do it again, I'd do it the same way (cause I'm too lazy to cut out new fins) and just put a strip of glass over the fin tab joints. Without the glass, they've held up to 20+ flights on mine.

Good kit choice, BTW. My dad did his Level 2 Cert with one

The stock fins are fine. Last launch mine did the good ole lawn dart on a J350W. Utterly destroyed, but the fins are all still there...It might be because I foamed the fincan

Great kit, you'll love it!

I just wanted to post a pic or two as I got started.... I have enjoy seeing people like Carl show how they build something..... So I am going to copy that idea.....

With that, the first pic is of the main parts of the kit.

And here are the parts with the addition of a longer motor mount tube and two extra centering rings....

That's all they give you for a motor tube?!? Seems kinda short to me...

Originally posted by gothique_97
That's all they give you for a motor tube?!? Seems kinda short to me...

Click to expand...

It's plenty long for AP motors - just need to hold it straight.
He wants to hybridize it though.

Originally posted by gothique_97
That's all they give you for a motor tube?!? Seems kinda short to me...

Click to expand...

Rocketjunkie is right..... This is my newest adventure..... Hybrid Motors...... You need a much longer tube......... This one is 24" long.......

And besides posting a lot of pic...... I plan to weight everything that goes into the final rocket......referring back to a thread a while ago about finding the CG and CP, Powerburner said the most accurate way is to weight each component along the way, thus enabling you to determine the amount of epoxy etc that goes into it......

I have weight the parts of the kit...... They total a little over 37 oz, the kit says the rocket weights 40oz..... I guess they are figuring 3 oz for epoxy........ The items that I have already "added" to the kit have added almost 5 oz........More updates to come............

Originally posted by Rocketjunkie
It's plenty long for AP motors - just need to hold it straight.
He wants to hybridize it though.

Click to expand...

<strike>Hybridizing or not</strike>, a motor tube that short leaves an awful lot of interal volume for the ejection charge to fill. That's always been my school of thought when designing a motor mount for a scratch build AP motor burner.

Despite several of you saying that the standard 2-piece fin was ok, I decided to make my own..... I ordered some 3/16" birch plywood..... Overkill? Maybe.... I just want it to be build as good as I can..........

I have been working on the motor mount tube.... I would post a pic, but my cheap digital camera only takes pictures with daylight.......

I did a little work on the motor mount........ I'm using some 1" webbing for the shock cord mount....... I've cut a small bit of the centering ring out (on the inside) so the webbing can run along the motor mount tube..... I'll epoxy the webbing the whole lenght of the tube.........

Here's a pic with the webbing......

Cool. Keep the build pics coming - I'm hoping to get one of these for my birthday or Christmas! Have you given any though to making it dual deploy? Any ideas how to do that with the transition there?

Loopy

Originally posted by Loopy
Have you given any though to making it dual deploy? Any ideas how to do that with the transition there?

Loopy

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I have to make it dual deployment..... Hybrid motors don't have ejection charges...... I think I will get a LOC electronics bay, just trying to figure out if I should put it on the 4" selection right before the transition or the 3.1" selection right after the transition......

Cool. Let me know what you decide so I can copy off of you later...

Loopy

I have now epoxy'ed the webbing onto the motor mount......

Loopy, I guess if you are going to copy me, I better not fall on my face with this one

Yikes! Potential gotcha with fin alignment and the end of the webbing. Looks good so far.

Potential gotcha, but you should be ready for it if you've ever built a PML kit.

Don't worry about falling on your face...lol I'm just messing with you! I just wasn't sure if DD was possible with the transition in the way there. I'm interested to see your solution.

Loopy

Originally posted by Rocketmanic
Here's a pic with the webbing......

Click to expand...

Kind of like PML and PE. A tip here is to replace the nylon with kevlar. The 5/8" tubular kevlar Magnum sells is a good replacement. And its fireproof too.


Al

Originally posted by rbeckey
Yikes! Potential gotcha with fin alignment and the end of the webbing. Looks good so far.

Click to expand...

Ok, tell me in more detail where the gotcha is....(before I mess it up)

Here is a pic of the motor mount going into the body tube......

And this is what it looks like all the way in....(2 aft centering rings left out for beter pic)

I once had an Expeditor, and it does bring back some good old memories. Make sure you epoxy those fins in place before you attach that last centering ring! Also, I did my best to epoxy the inner fin tab to the motor tube to make it more durable, and I added fillets internally after I got the fins on. I added the external fillets after I finished working the interior motor mount.

I kept my Expeditor used it for just about all of my launches. It got stuck in a tree once, suffered a lot of bumps and bruises but would come back for more every time I fixed it. I think the last time I used it, it had more then a good three heavy coats of paint (well, it's like railroads do to locomotives, use 'em, repaint 'em, and use 'em again, and repaint 'em....).

An interesting thing about the Expeditor: They are very efficient. Mine ran with an I motor, and I would have to chase it like a runaway labrador retriever! The standard amount of powder for a reload for chute deployment is usually sufficient. The rocket is usually at a low enough pressure to where the chute should open up relatively easily. Of course, with a hybrid motor, I'm not sure where you'll place your charges, but I assume you're going to use an altimeter to ignite the powder.

Good luck, and have fun with your Expeditor!

MrCoffee

Originally posted by MrCoffee
Make sure you epoxy those fins in place before you attach that last centering ring! Also, I did my best to epoxy the inner fin tab to the motor tube to make it more durable, and I added fillets internally after I got the fins on. I added the external fillets after I finished working the interior motor mount.

Of course, with a hybrid motor, I'm not sure where you'll place your charges, but I assume you're going to use an altimeter to ignite the powder.

Click to expand...

This project is on hold while I wait for my fin stock..... I didn't like the 2 piece fins that came with the kit..... The guys at my club gave me a few suggestions as far as the fins and fillets.......Here's the plan;

Extend the fin slot to the end of the body tube....... put the motor mount tube in and tack the fins to the motor tube (only)........ slide the motor tube and fins out........... epoxy the fins in real good, kind of like a fin can....... reinstall it into the body tube and epoxy the external fillets and centering rings...... install the aft centering rings........

And for the ejection charge...... Still trying to decide where to put the electronics bay (before or after the transition).......

Originally posted by Rocketmanic
Ok, tell me in more detail where the gotcha is....(before I mess it up)

Here is a pic of the motor mount going into the body tube......

Click to expand...

If you put the motor mount in the way it is in the picture, you avoided the gotcha. With the mesh where it is, if the tube was put in incorrectly, you could end up with the mesh under a fin slot, which would interfere with fin attachment. Like I said - I think you avoided it nicely.

I've been thinking about where to put the altimeter - I think putting it above the transition would be best. Two reasons - smaller diameter tube, less needed for the charges. Also, this would allow you to easier fly it on motor ejection if you ever wanted to. If you put the alt bay below the ejection, you might be limiting yourself in motor length as well. Just a couple of thoughts.

Loopy

Originally posted by Loopy
I've been thinking about where to put the altimeter - I think putting it above the transition would be best.

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Put the altimeter just above the transition or *in* the transition with the vents above the transition. You don't want the vents in the turbulence produced by the transition.

You can separate at apogee at the transition and the main chute in the smaller tube above the altimeter bay.

Ah- ha! That makes sense!

Loopy

Originally posted by Rocketjunkie
Put the altimeter just above the transition or *in* the transition with the vents above the transition. You don't want the vents in the turbulence produced by the transition.

You can separate at apogee at the transition and the main chute in the smaller tube above the altimeter bay.

Click to expand...

So, I get a LOC 3.1" electronics bay, put it just above the transition........ At apogee separate the rocket with lower body tube on one half and the transition, electronics bay and upper body tube on the other half? The ejection charge could be attached to the transition (pointing to the rear) When I set off the main ejection charge, I would push out the nosecone and chute? (ejection charged attached to the upper end of the electronics bay)

Using this method, I would need to secure the transition, electronics bay and the upper body tube... I could use t-nuts and screws right (t-nuts epoxied on the inside and screws from the outside......

Originally posted by Rocketmanic
At apogee separate the rocket with lower body tube on one half and the transition, electronics bay and upper body tube on the other half?

Yes.

The ejection charge could be attached to the transition (pointing to the rear) When I set off the main ejection charge, I would push out the nosecone and chute? (ejection charged attached to the upper end of the electronics bay)

Click to expand...

Again yes. The apogee charge would push the transition out of the 4" booster section.

What I would do is mount the altimeter in the transition with a 4" plywood disk as a cover. Mount the altimeter on a carrier that fits into the transition. Use screws to secure the 3" body tube to the front of the transition. The vents would go through the 3" body tube and shoulder of the transition.

Check stability of the booster section with a burned out Hypertek K240 in it. You don't want it stable. (Simulate it with a .001" long nose cone.) If it comes up stable, you will need a small drogue to prevent streamlining in.

The only rocket I have with a transition is my Cyclotron. I cut the larger tube in half and put the altimeter in the coupler holding the 2 sections together. Long motors don't fit though, I have to hang them out the rear somewhat and also coil the booster shock cord around the front of the motor.

(Call me if you want clarification.)

Well, I got my shipment of supplies in today...... Started work on the new fins...........

Here's a pic of the first one, just a rough cut........