Anduril Roadrunner

[lakeroadster]

Here's a Twin-Turbojet VTOL Autonomous Air Vehicle (AAV) Anduril Roadrunner

Lot's of potential as a powered glider, or as a rocket. Way cool.

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[BABAR]

Hmm, something @burkefj hasn’t done yet (to my knowledge, but I may be wrong!)

 

[lakeroadster]

A OpenRocket simulation shows it's a good performer using 24mm black powder motors. Screen grabs below don't show the elliptical body tube over the rear of the fuselage.
This simulation uses an internal stuffer tube with rear eject, something similar to a Sky Dart.

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[lakeroadster]

A bit more refining... I used a dual pod with an opacity of 0%, then used a wrap with a 50% gray color to give the illusion of the rear elliptical body tubes. Also profiled the edges of the fins to look more like the real thing.

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[BABAR]

So the dual motors will be ducted to a single central tube to the forward end?

The effect may be similar to my experience with ducting 18 mm to BT-5 and 24mm to BT-20, except worse because of the angle change, as inertia will tend to direct the hot clay particles forward indirectly off the ductwork’s internal wall.

Definitely do-able, may consider smearing the inside generously with JB Weld or other protectant if you plan to fly it more than once.

 

[lakeroadster]

So the dual motors will be ducted to a single central tube to the forward end?

The effect may be similar to my experience with ducting 18 mm to BT-5 and 24mm to BT-20, except worse because of the angle change, as inertia will tend to direct the hot clay particles forward indirectly off the ductwork’s internal wall.

Definitely do-able, may consider smearing the inside generously with JB Weld or other protectant if you plan to fly it more than once.

Wood Glue ​

 

[burkefj]

Hmm, something @burkefj hasn’t done yet (to my knowledge, but I may be wrong!)

No, it's a little dumpy looking, I have some standards......well maybe not

 

[lakeroadster]

More Updates

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[lakeroadster]

No, it's a little dumpy looking, I have some standards......well maybe not

Yeah... it really is too short for one of your birds. And stretching the tube changes the look.​

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Dumpy? One man's "dumpy" is another man's "bad ass".​

 

[burkefj]

Yeah... it really is too short for one of your birds. And stretching the tube changes the look.​

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Dumpy? One man's "dumpy" is another man's "bad ass".​

Its not too short for cg, just dumpy but if you like "big butts and you cannot lie"

 

[lakeroadster]

Its not too short for cg, just dumpy but if you like "big butts and you cannot lie"

Short and well proportioned...​

 

[BABAR]

Yeah... it really is too short for one of your birds. And stretching the tube changes the look.​

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Dumpy? One man's "dumpy" is another man's "bad ass".​

True. Of the two nuclear bombs dropped in anger, the less sleek one had a greater yield.

 

[lakeroadster]

Build This Thang...

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[BABAR]

Short and well proportioned...​

 

[Daddyisabar]

Its not too short for cg, just dumpy but if you like "big butts and you cannot lie"

The Desert Eagle might be manly but the ubiquitous 38 Special can get the job done!

 

[lakeroadster]

Nose Cone

Started with a 4 x 4 piece of scrap cedar. I lagged it to the headstock and turned the piece to 1-3/4" dia. and then bored a 0.90" dia hole x 5" deep. Finish cut O.D. to 1-5/8" dia. and then turned the shoulder for a C-55 and turned the taper.​

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[lakeroadster]

Motor Header

Two 24mm motors feeding into a BT-5 ejection tube.... so I needed some way to neck the ejection charges down. I took a piece of 3/4" plywood and made a header. I used plywood to avoid the wood splintering when the ejection charge fires.​

Plan is to glue the two body tubes to the header, and to themselves, and then use some wood glue on the inside surfaces as fire proofing.​

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[Daddyisabar]

I forsee a four motor header for a Nike Hercules! An 11 motor header for a Tantive IV Rebel Blockade Runner!

 

[BABAR]

FWIW, I’ve fed ONE 18 mm motor straight into a BT-5, and burned through in 2-3 flights. May need more than glue.

My rolled up aluminum can trick has worked.

Even aside from the heat, that’s a LOT of ejection charge to blow through an overgrown straw. Overpressure may raise it’s ugly head.

I’ve done a SINGLE 24 mm to BT-5 and it blew out the motor right through the motor hook.

That’s why my Tank Killer is no longer rear eject.

 

[lakeroadster]

FWIW, I’ve fed ONE 18 mm motor straight into a BT-5, and burned through in 2-3 flights. May need more than glue.

My rolled up aluminum can trick has worked.

Even aside from the heat, that’s a LOT of ejection charge to blow through an overgrown straw. Overpressure may raise it’s ugly head.

I’ve done a SINGLE 24 mm to BT-5 and it blew out the motor right through the motor hook.

That’s why my Tank Killer is no longer rear eject.

All this rear eject needs is just a nudge... I'll friction fit the motor, and if it ejects that'll be fine. Should be fun, blow or go.​

 

[BABAR]

I know, I’m chicken little…..

 

[jqavins]

Motor Header

Two 24mm motors feeding into a BT-5 ejection tube.... so I needed some way to neck the ejection charges down. I took a piece of 3/4" plywood and made a header. I used plywood to avoid the wood splintering when the ejection charge fires.​

Plan is to glue the two body tubes to the header, and to themselves, and then use some wood glue on the inside surfaces as fire proofing.​

View attachment 642371 View attachment 642372View attachment 642373 View attachment 642374View attachment 642376 View attachment 642375​

Mmmm, toasty!

I know, I’m chicken little…..

That makes two of us. It may be overkill, but I'd use thick walled BT-5 (buy if possible, make if need be) for strength, and swab it with thinned JB Weld for flame resistance.

 

[lakeroadster]

Motor Mount Day 02

Glued the 24mm tubes to the header, and started building fillets. Also started fireproofing the header internal parts with wood glue.​

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[lakeroadster]

.... It may be overkill, but I'd use thick walled BT-5 (buy if possible, make if need be) for strength, and swab it with thinned JB Weld for flame resistance.

Good advice. I'll be using a BT-5 with an internal Starbucks Straw. Should make for a Hell-For-Stout Ejection Tube.​

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Those folks at Starbucks... man, they got everything.​

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[jqavins]

And here was I, thinking of spending good money on a piece of coupler stock. I am such a sucker!

 

[lakeroadster]

.... I am such a sucker!

They have suckers too.... ​

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The straws were in the common area... I grabbed 2 or 3, they come in pink or blue.​

 

[BABAR]

They have suckers too.... ​

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The straws were in the common area... I grabbed 2 or 3, they come in pink or blue.​

I smell MicroMaxx fodder.

Don’t tell @kuririn !

 

[lakeroadster]

Wings & Motor Mount Day 03

I cut the wings from 1/4" plywood and the Vert. Stabilizers from 1/8" Basswood.

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[lakeroadster]

Gluing the Wings

Once I laid out the wings and the body tube I found that the motor mount was wider then the distance between the fins. So I modified the fins slightly.​

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The body tube was cut so the fins could glue to the inner coupling.​

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I used the 1/2" thick (actually 0.4375) plywood fin alignment fixture that I made for my Level One rocket. A few playing cards were added under the body tube to get the fins on C/L.​

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Wood glue was applied to the tube, then Wing #1 was set into it and removed. The procedure was repeated for Wing #2. The tube was placed in the fixture, and then the wings were set into place. The 12" Steel Scale holds the wings flat.​

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Now.... we wait.​

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[lakeroadster]

Attaching Nose Cone to Body Tube

Gorilla Wood Glue to the rescue...​

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