Lakeroadster's X-Wing Alpha Build Thread

[neil_w]

Something doesn't seem to add up on the bottom right; perhaps it's me.

1/16" basswood, before paper: 0.297 oz/in³​

Paper: 0.476 oz/in³, which is more than the wood!​

Paper is denser than wood. Where's the problem?

 

[jqavins]

Where's the problem?

In my brain. I've edited the post away, as I found my own error moments before you posted. Would that you had not read so fast, my foolishness might never have been discovered.

(The error, for the record, is that although the table clearly listed standard (volumetric) density, by brain processed it as area density, oz/in² or g/cm². 11 mil thick paper can't be heavier by area than 62 mil thick basswood. And the calculations on the left side clearly show that it is not heavier, so the right side had to be wrong. But all that is irreverent, since it's all related to the wrong quantities.)

 

[lakeroadster]

I did a strength test on the wood glue papered fins. It feels so strong I just had to know how much stronger.

I tested the bending strength, in the weak axis, bending it along the wood grain.

The raw 1/16" basswood piece failed with 851 grams of weight. The basswood snapped into (2) pieces.​

​

The papered 1/16" basswood failed with 6,988 grams of weight. The basswood snapped, the top paper ripped across, the bottom paper was still intact.​

So that's about an 8:1 increase in bending strength. Pretty amazing, right?

 

[lakeroadster]

In my brain. I've edited the post away, as I found my own error moments before you posted. Would that you had not read so fast, my foolishness might never have been discovered.

(The error, for the record, is that although the table clearly listed standard (volumetric) density, by brain processed it as area density, oz/in² or g/cm². 11 mil thick paper can't be heavier by area than 62 mil thick basswood. And the calculations on the left side clearly show that it is not heavier, so the right side had to be wrong. But all that is irreverent, since it's all related to the wrong quantities.)

It's all good.. no worries.

 

[Sandy H.]

I did a strength test on the wood glue papered fins. It feels so strong I just had to know how much stronger.

I tested the bending strength, in the weak axis, bending it along the wood grain.

The raw 1/16" basswood piece failed with 851 grams of weight. The basswood snapped into (2) pieces.​

​

The papered 1/16" basswood failed with 6,988 grams of weight. The basswood snapped, the top paper ripped across, the bottom paper was still intact.​

So that's about an 8:1 increase in bending strength. Pretty amazing, right?

View attachment 515483 View attachment 515484 View attachment 515485
View attachment 515487 View attachment 515488 View attachment 515489

Similar, but not the same for sure:

Shame RP is gone (for more reasons than just this example). . .I'll have to figure out what the heck the acronyms I was using meant. . . DOH!!!!

I was doing the water bucket method the whole time. Apparently I was losing hair back in 2011 and never noticed. Oddly enough, I'm currently wearing those exact glasses (blue color clued me in) as I grabbed the wrong pair the other day and these are the backup. I'd say that means I'm doing awesome eyesight wise, except i have to backspace every few characters to spell the words you're reading as well as I have so far. My fingers are getting tired!!!!

Sandy.

 

[lakeroadster]

Similar, but not the same for sure:

Shame RP is gone (for more reasons than just this example). . .I'll have to figure out what the heck the acronyms I was using meant. . . DOH!!!!

I was doing the water bucket method the whole time. Apparently I was losing hair back in 2011 and never noticed. Oddly enough, I'm currently wearing those exact glasses (blue color clued me in) as I grabbed the wrong pair the other day and these are the backup. I'd say that means I'm doing awesome eyesight wise, except i have to backspace every few characters to spell the words you're reading as well as I have so far. My fingers are getting tired!!!!

Sandy.

Sandy,

So the test you posted, it was used to compare different adhesives being used to attach a fin to a body tube?

1. What was the material of the fin?
2. What was the material of the body tube?
3. What is USC?
4. What is CA1?
5. What is CA2?

I'd love to glean some information from the video, but as presented, I can't.

 

[lakeroadster]

Cockpit Prep & Attaching the Cockpit to Fuselage

The wiffle ball had such a smooth surface I doubted that paint, or glue, would stick to it very well, in the long haul. Using my trusty wood lathe, I sanded it with 220 grit.

Mentally I did some flip flopping in regard to what glue to use. The ball cockpit has no structural contribution in regard to the success of the rocket, it's just there for looks. There are gaps that needed to be filled in, therefore CA doesn't seem to be a good choice. I thought about using Duco Cement, but the instructions state it's not recommended for polyethylene, and that's what the wiffle ball is made from. I ended up settling on wood glue. All the glue joints are double sided, accessed via the wiffle ball slots.

To help ensure the wood glue had plenty of surface area to adhere to I bored some holes, using an x-acto knife, through the ball near the wood glue joints.

 

[Sandy H.]

Sandy,

So the test you posted, it was used to compare different adhesives being used to attach a fin to a body tube?

1. What was the material of the fin?
2. What was the material of the body tube?
3. What is USC?
4. What is CA1?
5. What is CA2?

I'd love to glean some information from the video, but as presented, I can't.
View attachment 515563

Well. . . I wish I could answer 100% factually, but at best I'll give it a shot. I WISH there was a way to access the old Rocketry Planet forums. I tried the Wayback Machine, but no joy. I can only imagine that someone, somewhere has access to the server, but likely the content will never surface again. . .very sad.

Anyway, around that time, I was learning to do fiberglass stuff and that is likely what I was experimenting with. There is another video on my channel that goes over the set-up. I think the fin material was just balsa.

It was a fiberglass tube that I hand wrapped, not commercial fiberglass. I *think* all I was doing was testing different adhesives to attach to the fiberglass tube. I am 99.9% certain that USC means US Composites, 5 means Bob Smith 5 minute epoxy and CA means. . . CA. Regretfully, I don't know what CA1 and CA2 might mean. Could be brands or could be CA once and attach vs CA once, let it dry then CA again to attach. Totally just a guess, here.

Green vs Cured would most likely be the state of the tube when the fin was attached, i.e. I made the tube and while it was still green and not fully cured, attached the fin and let it finish curing. Not sure why I said wet 5, as I can't imagine I would have tried to attach a fin to wet fiberglass with 5 minute epoxy. . .

Sorry I don't have more info. I wasn't posting the video as a recommendation of a material to use, just showing how it was similar in method to what you had posted (i.e. weight break test). When I initially looked at the pics, I thought the orange bucket was being filled with water, but later saw that you were adding metal to a hook. You might want to give the water bucket method a try sometime as well.

Sandy.

 

[lakeroadster]

Anybody else use this technique?

(184) The Model Rocket Wood Glue Centrifuge - YouTube

 

[lakeroadster]

Gluing Fins To The Fuselage

The pictures are pretty self explanatory. I used playing cards to shim the solar array wings to their correct vertical locations.

 

[lakeroadster]

Wing Glue Fillets and Front Spar

Tightbond Quick and Thick for the fillets. The TIE Starfighter self-balances for wing fillets... yeah... it was designed that way for ease of maintenance lol jk


Cut and sanded the front spars from 1/16" Basswood, then cut part way thru the center of the spar, formed the peak over a scrap piece of wood, and then applied Gorilla Wood Glue into the split. Saves a bit of weight over using a 3/16" piece that is beveled, like was originally planned.

 

[lakeroadster]

Front Spars

Just about ready to lash this up to the X-Wing and do a swing test.

 

[lakeroadster]

I've been thinking about how to swing test the "Luke and Vader Dog Fight Rocket" such that the string at the CG won't buckle the interconnecting tube.

Think this would work, or will the extra mass result in a bogus test? My mindsim say it should work as long as the CG is representative of the flight ready rocket.

I'm thinking about adding a "grid" panel that goes all the way across the back of the TIE, from solar array to solar array, then decreasing nose weight as much as possible.

 

[Sandy H.]

I've been thinking about how to swing test the "Luke and Vader Dog Fight Rocket" such that the string at the CG won't buckle the interconnecting tube.

Think this would work, or will the extra mass result in a bogus test? My mindsim say it should work as long as the CG is representative of the flight ready rocket.

View attachment 516063

Broom handle seems like it would weigh a bunch. If nothing else, it would be harder to get swinging, I'd think. Maybe some used motors glued together. I think you're wise to be concerned, though. Not sure i would have thought about it before kinking it. Maybe if the motors or broom stick are too heavy for practicality, you could split a few tubes lengthwise and snap them over the outside of the real tube and tape them back together.

Just a few thoughts, not sure if they are valid at all.

Sandy.

 

[lakeroadster]

Broom handle seems like it would weigh a bunch. If nothing else, it would be harder to get swinging, I'd think. Maybe some used motors glued together. I think you're wise to be concerned, though. Not sure i would have thought about it before kinking it. Maybe if the motors or broom stick are too heavy for practicality, you could split a few tubes lengthwise and snap them over the outside of the real tube and tape them back together.

Just a few thoughts, not sure if they are valid at all.

Sandy.

Thanks for the input. FYI: A 12" long piece of spruce broom stick only weighs about 3 ounces

 

[jqavins]

I think your solution is fine. Carefully locating the broom handle may be more effort than adding nose or tail weights as necessary. As long as the CP and CG are in tne right places and you're able to swing it, you're good to go.

If it gets really heavy, be sure to upgrade the string to 1/4" Kevlar.

 

[BABAR]

Any chance a Kite like bridle (one string attached at two points, one fore and one aft) with your main line attached to the bridle would work?

 

[lakeroadster]

Any chance a Kite like bridle (one string attached at two points, one fore and one aft) with your main line attached to the bridle would work?

A kite bridle. Sure, that "crossed" my mind, but will that interfere with the rockets ability to freely pitch and yaw about the cg. Sure if everything is mounted perfect it probably would work, but if the alignment is slightly off it'll induce some loadings (side slipping etc.) that are not real world.

The cg location on the interconnecting tube makes it super easy to attach the string at the cg, but the nose is pretty heavy and would hate to do a David's slingshot with either the X-Wing or the TIE.

The rear grid fin should greatly reduce the nose weight needed. Think spool, with a sustainer attached, as long as the base drag doesn't cause separation. I can easily make the grid fin detachable. Excuse my 3rd grade sketch..

 

[lakeroadster]

Rear Stability Screen

Went ahead and started to build the rear stability screen so I could use it during the swing test.

The perimeter is made from 1/8" poplar dowel stock, the plan is to use some screen material (used for windows and doors) attached to frame.

My mind sim shows this will perform almost like a parachute, adding a high level of stability.

 

[lakeroadster]

Swing Test Dowel

Cut a 3/4" dia. dowel to length and added green painter's tape to fit it to the BT-50H tubes. This dowel will only be used during the swing test and the rocket will be weighted so the CG with the dowel mimics the flight ready CG of the finished rocket.

 

[dhbarr]

Tether them together, then tractor pull from the x wing tips.

CAUTION: contains no actual advice

 

[lakeroadster]

Rear Stability Screen... Redeux
We washed the windows on our house today.... And the Windex bottle inspired me.

My in-process home brewed stability screen (see posts 378 & 379 above) just didn't mindsim as durable enough. I had thought something clear would be neat... and the shape of that Windex bottle is just funky enough to work. It even has reinforcing spokes built into it.

It'll be retained by a few wraps of masking tape around the motor.

I was planning to swing test the rocket today... but we're having 50 mph gusts.. 🌪 .. so perhaps that dictates a postponement?

Maybe tomorrow or Sunday I can get the X-Wing's nose into the wind for some hot laps.

Tomorrow, tomorrow, I'll swing you, tomorrow, it's only a day away.

 

[lakeroadster]

 

[Daddyisabar]

Wow! Vader's TIE is a real drag queen! Be cognizant of Booster motor lift off capacity. Don't want to stage too low or without enough momentum resulting in a veered staging.

You must feel the force flowing between the rocket, the motor, the atmosphere...Gravity well you have found! Oh the mindsim of the Youngling Swing Kids! Found Master Kenobi's stability issues have we!

 

[lakeroadster]

Wow! Vader's TIE is a real drag queen!

Didn't he wear a black dress? I'm not judging, merely an observation. Rumor has it he started Trans World Airlines.

Be cognizant of Booster motor lift off capacity. Don't want to stage too low or without enough momentum resulting in a veered staging.

​

All good points:

D12-0 Motor Lift Off Capacity: 14 ounces. Rocket weight 10.5 ounces.​

​

Stage Separation​

Altitude: 83 feet​

Velocity: 44 mph​

​

 

[Daddyisabar]

Didn't he wear a black dress? I'm not judging, merely an observation. Rumor has it he started Trans World Airlines.

​

All good points:

D12-0 Motor Lift Off Capacity: 14 ounces. Rocket weight 10.5 ounces.​

​

Stage Separation​

Altitude: 83 feet​

Velocity: 44 mph​

​

View attachment 516509

The drag will be less in the thin Rocky Mountian air on a hot, dry, summer's day. Like me droogs say; the mindsim is as clear as the azure sky of a mid summer's day. Time for a little ultraviolence down in the trench and then off to the Korova Milk Bar for some milk plus. I like mine with drencrom, but vellocet is nice too.

 

[Daddyisabar]

Didn't he wear a black dress? I'm not judging, merely an observation. Rumor has it he started Trans World Airlines.

​

All good points:

D12-0 Motor Lift Off Capacity: 14 ounces. Rocket weight 10.5 ounces.​

​

Stage Separation​

Altitude: 83 feet​

Velocity: 44 mph​

​

View attachment 516509

With this rocket Vader could show up in a pink sith suit and the ultra conservative, hardened Cold Warrior Top Men would grant a pad assignment to see it fly! With a new an interesting rocket they all seem to find their deeply repressed, inner oddroc scuminess.

 

[lakeroadster]

Swing Testing

The extra weight of the wooden coupling dowel (used only for the swing test) made the rocket lethargic, slow to react. I feel this test was sufficient to prove that the stability screen does in fact make the rocket stable. However, another test will be performed of the flight ready rocket, using A C-50 coupler tube, before launch.

The video's are best viewed at 1/4 speed, where you can see the orientation of the rocket.

Luke and Vader Dogfight Rocket Swing Test With Stability Screen - YouTube ​

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Luke and Vader Dogfight Rocket Swing Test Without Stability Screen - YouTube ​

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[Daddyisabar]

It whistles with the rear deflector shield engaged! Only Vader gets hyper drive and deflectors on his TIE fighter.

 

[lakeroadster]

It whistles with the rear deflector shield engaged! Only Vader gets hyper drive and deflectors on his TIE fighter.

I'll admit, when I put the rear shield on... I thought about Captain Kirk ordering the shields raised.