TRF Summer Build Off: Babylon 5 Starfury

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grapetang

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Well, this may be a little foolhardy and I'm likely to crash & burn assuming I can get this done, but I'll attempt the Babylon 5, Earth Alliance Mitchell-Hyundyne SA-23E Starfury:

starfury.jpg <-- Artwork by Randy Asplund for the Revell/Monogram kit.

Blueprints are here: https://www.starshipmodeler.com/b5/b5tech.htm

I don't think I can get it stable without adding something though. And so it begins (at a snail's pace)...
 
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dhbarr

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With those aft fins swept out and a tractor in the main, I bet it'd fly just like a cone / saucer.
 

Screaminhelo

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With those aft fins swept out and a tractor in the main, I bet it'd fly just like a cone / saucer.
I tend to agree but you need to build it to prove the tbeory:wink:
 

Salvage-1

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OMG....!!!

YES

yup swept wings ... pods... drag queen
 

KenECoyote

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Ooooh...I like! :grin:

The overall shape somehow reminds me loosely of the Guardian of the Galaxies' Milano (except for the outer pods obviously):

I had gotten one of the toy ships on clearance meant for a PMC (Plastic Model Conversion), so I may be able to gain from your experience. :)
 

jqavins

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The overall shape somehow reminds me loosely of the Guardian of the Galaxies' Milano (except for the outer pods obviously)
I've always that those things look suspiciously like Star Wars X-Wings, which are another mandatory PMC. I've never done a PMC, but an X-Wing will be my first or second.
 

dhbarr

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I've always that those things look suspiciously like Star Wars X-Wings, which are another mandatory PMC. I've never done a PMC, but an X-Wing will be my first or second.
Of note, last time I was at Walmart they had a huge stack of epVII X-Wings for a pretty steep discount.
 

Cabernut

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No-waaaayyy! That is going to be awesome!

Are you thinking of having four motors just like in the pic?
 

grapetang

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With those aft fins swept out and a tractor in the main, I bet it'd fly just like a cone / saucer.
I tend to agree but you need to build it to prove the tbeory:wink:
OMG....!!!
YES
yup swept wings ... pods... drag queen
I'm not quite sure but we'll find out. The 4 wings aren't equally spaced. I was planning to build to the CG model but it occurred to me that it's stubbier than the artwork so it may need some help. The pitch control might be OK but the yaw isn't. I hope I don't have to deviate too much. The Thunderbolt would've been easier.

Whoa. This is the best contest. That things awesome looking.
I agree about the contest! Everyone has such innovative designs! I hope I can do this one justice, or have it die trying. :)

Ooooh...I like! :grin:
The overall shape somehow reminds me loosely of the Guardian of the Galaxies' Milano (except for the outer pods obviously)
Nice ship! It was a candidate too though the starfury looks easier to convert to rocket power. I'd love to see your take on it.

I've always that those things look suspiciously like Star Wars X-Wings, which are another mandatory PMC. I've never done a PMC, but an X-Wing will be my first or second.
I'd love to see that too! :) More things on the list...

No-waaaayyy! That is going to be awesome!
Are you thinking of having four motors just like in the pic?
Alas, no. The torque on the ship would be horrible if all 4 main engines don't light simultaneously. Just one main tractor motor in the front with lots of nose weight. I'm hoping for 18mm if possible, 24mm as a backup.

Thanks for the comments, guys. I need to get this going! :)
 

grapetang

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Darn, running out of time. Life is hectic right now and I don't think I can make the deadline but will try anyway...

OpenRocket pseudo-sims aren't working. The starfury was designed really well in that the CG and CP land almost on top one another despite any nose weight I attempt to add (reduces rotational stress on the pilot?). I've tried sweeping the wings more but it's not helping much. This thing would make a great booster though.

The still-in-progress boilerplate test vehicle is made from rolled tubes and scrap cardboard. Still need to add the top & bottom cowling, the inner engine fins, and some wing supports.

I'll add nose weight and try the swing test but have low expectations. Pitch might be OK but yaw may need something like the NCR x-wing supports. Anyone have any suggestions? Add 4x aft ring fins or 4x aft circle-shaped exhaust fins in addition to the NCR x-wing-like supports?

DSC_0376.jpgDSC_0377.jpgDSC_0378.jpg
 

jqavins

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With the engine that far forward, I'm shocked if it's not stable. If you'll forgive a stupid question, you did get those sim results with a motor in place, yes? Usually that hurts, but it looks like this time it would help.

Please post your design file(s).
 

Cabernut

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Looks like it would be stable to me as-is. I'd do a test flight with as small a motor as possible, with no one else around just in case.
 

hornet driver

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Very,very ,very cool !! If I had to call it, I'd say your close on stability but good to go! Fin alignment will be everything on this baby. Hope there's no flutter!--H
 

rstaff3

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Ack, another cool build I had missed. If this one (a Nick 'EMRR' Esselman kit) flew, yours should be doable.

lambda_1.jpg
 

Flyfalcons

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If anything you could add some small vertical fins on the back of the wings, midway out like how the Estes Crossfire ISX fins look. That would help with yaw stability and preserve the look of the ship.
 

grapetang

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Thanks for all the suggestions & words of encouragement! I've included my OR sim below, fixed since I originally forgot the fin radial offset. Responses to comments:

- yes, the sim includes the motor (always good to check! :) )
- the NC+BT combined is very short (2.75"); since the cone is so short, the motor isn't as far forward & extends out the back about 3/4" :(
- fin flutter will be an issue with the cardboard boilerplate model
- not sure if it really applies but I tried to account for the base drag
- haven't accounted for the little fin drag which should pull the CP back
- small Crossfire-like fins will help - thanks!

That lambda shuttle is neat! It'd be nice if the starfury had a longer nose to put the weight, like the B5 thunderbolts. I'll need to check the weights too.

<sigh> "Real Life"(tm) is getting in the way...

View attachment starfury5a.ork
 

grapetang

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You guys were right!!! In Valen's name, it's stable!!! I added 20g of nose weight and it swings properly in pitch & yaw!

I'm using a bolt, nut, & washers for now since I don't have BB's nor lead sinkers around. The nut & bolt unfortunately have to recess into the motor itself (due to lack of space) so I won't be able to use C6's until I change the arrangement. The top of the bolt currently butts directly against the cone.

I'll see how it does after adding the cowlings, small fins, and some details. I don't know if I'll have time to test with pods...

DSC_0379.jpgDSC_0380.jpgDSC_0381.jpg
 

jqavins

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With the bolt and nut stuck in the top of the motor, how will you manage recovery?
 

grapetang

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Recovery?!??? D'oh!!! :facepalm:

Good question. The thought was to do rear-eject:

- motor taped to the motor/engine mount at the back
- motor mount w/ or w/o tethered bolt, tethered to the starfury with chute

Option 1: permanently attach the bolt to the cone like a typical rocket;
simpler setup but heavier starfury on recovery & possibly more likely to come in ballistic on a recovery failure

Option 2: the bolt is tethered to front of the motor mount via kevlar (if I can find any) or elastic, and is also pulled out;
slightly more complicated but the starfury itself will be lighter & perhaps less prone to damage on landing

An additional option would be for the motor mount assembly to come back separately from the starfury. For option 2 with the bolt, there's a possibility of entanglement from the bola-like motor mount assembly. Glide recovery had also crossed my mind for the starfury itself, but I need to take things one step at a time.

I'm open to suggestions! :) Thanks for question and the interest!
 

jqavins

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One possibility, if you can get the motor and bolt both ejected then what's left looks like it might tumble adequately. And you shoud have a streamer attached to the motor-bolt combinaton, or that thing might really hurt someone.
 

grapetang

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Congrats to Flyfalcons, EXPjawa, KenECoyote, and all the participants (cool designs!) and big thanks to Scotty Dog & helpers (blackbrandt, others?) for putting on the contest. Good motivation to get me building!

As expected, I'm way late but I'd still like complete the design. I have a small window to launch that I'm aiming for.

Some progress: top cowling & side supports added (more corrugated cardboard):

DSC_0385.jpgDSC_0386.jpgDSC_0387.jpg
 

grapetang

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Main engine pods & centering rings:

- Centering rings glued to cereal box cardboard
DSC_0388.jpgDSC_0389.jpg

- Parts slit to allow sliding onto wings
DSC_0390.jpgDSC_0391.jpg

- Centering rings attached
DSC_0392.jpg

- Main engine pods (transition) attached
DSC_0393.jpgDSC_0394.jpg

She currently weighs in at ~58g and I haven't put on the bottom details and engine front & end caps. I'll probably omit the directional thrusters for this boiler plate. She's getting a little heavy. and no recovery gear yet.

Still stable with a B6 in pitch and yaw though the CG has move 0.5" rearward. :( Hope I can make more progress! :)
 

Scotty Dog

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THANK YOU !
Glad you are finishing this bird.
LOOKING AWESOME!!!!!!!!!
 

Cabernut

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I'm glad you're finishing post-contest. That is really looking cool!
 

blackbrandt

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The contest was really fun to run. I loved seeing the really cool ideas. I have a feeling if you had finished yours it would have scored really high. :) Looks AWESOME!!
 

grapetang

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Thanks for the encouragements, guys! I had to rush it to fly this morning.

- Making 5mm ring in front of rear exhaust cones
DSC_0395.jpgDSC_0396.jpg

- Front caps & rear cones
DSC_0397.jpg

- Slots cut for wing & for ion suppressors (lots of trial & error)
DSC_0398.jpg
 

grapetang

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Been rushing the past few days... it's as done as it's going to be.

- front engine caps & rear exhaust cones added
- greebles & nurnies added to underside
- launch lugs added to upper side (upper cannons)

No time to add the lower cannon details nor the smaller ion suppressors, along with omitting the directional thrusters.

View attachment 302160View attachment 302161View attachment 302162View attachment 302163
View attachment 302164View attachment 302165View attachment 302166

Edit: weird, pics aren't showing unless you click them. Now displayed on next two posts.
 
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