HPR X Wing T70 Scratch build

I’m kicking off another Starwars themed build. I’ve decided this time to build the T70 model X-Wing as seen in the force awakens and the last Jedi. I had intended to only post on the Australian Rocketry forums, however it has been requested that I keep people here on TRF informed so I will post major milestones here as well. If any of you would like to contribute to the build thread I would prefer it if you could do so on the Aus Rocketry forum, but will take whatever feed back is on offer.

The T70 model X-Wing varies from the original X Wing in the engine design and outer wings. This will be approximately double the size of the previous scratch built X Wing I built so will be about 1.2m or 4 feet long. In keeping with the size doubling it will also use a single 38mm motor. I’m aiming to be able to typically fly G or H motors, but there will be room in there for a 3 grain CTI so potentially I motors too.

So here’s a reminder of what I’m trying to achieve. Note the T70 has the engines that seperate when the wings are apart


Detailed build thread is here
https://forum.ausrocketry.com/viewtopic.php?f=10&t=6017&p=69388#p69208

Yeah, well don't go too large. Those wings have a tendency to flutter badly. Some years ago there was a very large version of an X-Wing Fighter that was launched under dubious safety conditions. The rocket disintegrated. Fortunately no one was injured. There's a video floating around out there and there was a lot of criticism as the launch site was pretty crowded and the Builder had their doubts about flight worthiness. Not a pretty picture. Kurt

Do you have a pic of your smaller version?

I was also worried about wing twist on this version due to the large cutout compared to the original xwing design.

Looks good though.

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ksaves2 said:

Yeah, well don't go too large. Those wings have a tendency to flutter badly. Some years ago there was a very large version of an X-Wing Fighter that was launched under dubious safety conditions. The rocket disintegrated. Fortunately no one was injured. There's a video floating around out there and there was a lot of criticism as the launch site was pretty crowded and the Builder had their doubts about flight worthiness. Not a pretty picture. Kurt

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That was a full scale x-wing.


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While the full scale version had that issue so have two smaller J and K powered versions I have seen flown and both had fin spans about 3' long. Both ended in shreds.

markkoelsch said:

That was a full scale x-wing.

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I believe it was 1/2 scale. It definitely wasn't full scale. But, yeah, it was big. And, yes, it wasn't successful.

It was 21 feet long per this article.

https://www.google.com/amp/s/gizmod...del-actually-flies-updated-built-in-r2-d2/amp


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Fin span and thickness have the most theoretical impact on flutter according to an Airforce article where they ripped the fins off a Mach 4 rocket. Span had a higher influence than thickness. Material selection is important and get AeroFinSim if in doubt.

I think you could build one to take a 29mm H or I motor. You may have to play with FinSim program for material type and thickness. If it still wants to flutter by too much span you could model with wings in a folded configuration to shorten span. Aluminum 6061T6 wouldn't flutter as bad as G10 in FinSim from my experience playing with program. G10 was rather stout material. Out.

My logic is if you scale it for a smaller diameter motor you are reducing the fin span of the model which seems excessive. It would reduce costs too. You could even play with 24mm L-1 G motors in CTI 24mm 6 XL casing. So you could reduce thrust and lower the model maximum velocity also if needed. Or you could go semi scale and model the fins shorter span than exact scale. Many ways to solve problem.

I would fold a fin over itself at midpoint of span or make as solid piece to reduce flutter and try to call it a stored configuration. It would look awkward. You would double thickness to fins while halving the span too. My opinion.

Here's what really happened to it.

[YOUTUBE]QgF9hBL-CuA[/YOUTUBE]

Thanks for the feed back guys.

My previous build thread can be found here for those who are interested https://forum.ausrocketry.com/viewtopic.php?f=10&t=5704

I used balsa on the original version for the fins so am reasonably confident that the 3mm ply will do the job. However one of the fins was cut with the grain in the wrong direction so I’m thinking of reinforcing it with a thin layer of wests. Also rest assured, like the previous model there will be at least one trial flight on a quiet launch day.

Handeman said:

Here's what really happened to it.

Click to expand...

I could guess what was coming, but still awesome.

Your other build looks good, impressed with how straight it flew on the multi motors. I think if you cheat a bit like you did on that one and have a wider than standard "X" you can avoid the fins and be stable. Again, I think my only worry is the stiffness of the long span wings, expecially with the T-70 version with the major cutouts of the wings compared to the earlier version will be a problem. I'd not push the model too fast.

Frank

This looks great. Largest X-Wing I've flown is an Estes Maxi-Brute. Well, actually 2 of them. Both crashed, partly due to insufficient motor, partly due to delays that were far longer than nominal, though I did get one good flight out of the first one!

burkefj said:

Your other build looks good, impressed with how straight it flew on the multi motors. I think if you cheat a bit like you did on that one and have a wider than standard "X" you can avoid the fins and be stable. Again, I think my only worry is the stiffness of the long span wings, expecially with the T-70 version with the major cutouts of the wings compared to the earlier version will be a problem. I'd not push the model too fast.

Frank

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Agreed, the idea is to tweak the design so it’s stable yet still looks acceptably close to the real deal (especially as viewed during flight). Opening the wings a little wider was a better option IMO than adding vertical stabiliser as I’ve seen on other models. As for wing strength this is definitely as big I would build without adding fibre glass, probably also a layer on the body (then were talking J or K motor). It’s not supposed to be a super fast model, the whole point of the thing is put on a show. Quick off the pad sure, but sort burn only up to about 2000 feet or so, no point going high people what to see it.

SpaceManMat said:

Agreed, the idea is to tweak the design so it’s stable yet still looks acceptably close to the real deal (especially as viewed during flight). Opening the wings a little wider was a better option IMO than adding vertical stabiliser as I’ve seen on other models. As for wing strength this is definitely as big I would build without adding fibre glass, probably also a layer on the body (then were talking J or K motor). It’s not supposed to be a super fast model, the whole point of the thing is put on a show. Quick off the pad sure, but sort burn only up to about 2000 feet or so, no point going high people what to see it.

Click to expand...

I'm confused, are you planning on fiber glassing the body?

What about g10 for the wings then you could add a layer of glass from wing to body.

What do you think your AUW will be? I would think in a model that size you should be able to fly on G-H motors if you manage weight. It's pretty draggy so you will probably need to keep your weight in the 3 pound range maybe. In my experience, even a good straight flight to 1000' in a model that size is still nice, and you can see the entire thing. In that mindset I think the majority of strength needed will be for landing. To reduce tail weight, you may design for long 29mm motors instead of short 38mm motors, it gets the weight forward especially in a model like this where the cg won't be that far forward.

Frank

Well this build has finally seen some traction...

Over Christmas holidays I 3D printed a BB8 unit and maintenance cockpit.

BB8 in Cockpit on Flickr

I’ve also done the first dry fit of the wings

First Fit Wings on Flickr

Plenty of additional details and pics on the build thread...
https://forum.ausrocketry.com/viewtopic.php?f=10&t=6017#p72482

burkefj said:

What do you think your AUW will be? I would think in a model that size you should be able to fly on G-H motors if you manage weight. It's pretty draggy so you will probably need to keep your weight in the 3 pound range maybe. In my experience, even a good straight flight to 1000' in a model that size is still nice, and you can see the entire thing. In that mindset I think the majority of strength needed will be for landing. To reduce tail weight, you may design for long 29mm motors instead of short 38mm motors, it gets the weight forward especially in a model like this where the cg won't be that far forward.

Frank

Click to expand...

Frank, my simulation is for up to 1.8kg (under 4 pounds) that’s with a I180 Sparky which is as big as I think I would go, should be a nice scenic flight to 1300 feet. But will probably start out with a G motor and work my way up... As for drag, my experience is that the X Wing really isn’t as bad as you might think. The main issue I had with the low power model was getting the chute out at the right time, I will be flying a raven on this model so chute deployment should not be an issue.

Mendal said:

I'm confused, are you planning on fiber glassing the body?

What about g10 for the wings then you could add a layer of glass from wing to body.

Click to expand...

I was not, but if I did then I’d probably fly J sparkies, would be a sight to behold

Some more progress, 3D printed nose with electronics.


Nose Cone on Flickr

Wing have been attached and rear body has been build.

Body Pannels on Flickr

Lots of other details and pics can be found at Aus Rocketry Fourm https://forum.ausrocketry.com/viewtopic.php?f=10&t=6017&start=15#p72647

Lots of progress on this build.
Cast a lead nose weight using 3D printing technique

Nose Weight Cast Result on Flickr[/quote]

Body is nearly finished.

Nose Completed on Flickr

Hopefully flying next month. More details of the build can be found here https://forum.ausrocketry.com/viewtopic.php?p=73781#p73544

Following

It’s been over 2 years in the making but I’m pretty much ready for the first test flight hopefully later this month.

X Wing Ready for testing on Flickr

More details https://forum.ausrocketry.com/viewtopic.php?f=10&t=6017&start=30#p73812

Very well crafted!

SpaceManMat said:

It’s been over 2 years in the making but I’m pretty much ready for the first test flight hopefully later this month.

Click to expand...

All you need is a good blaster by your side.

Flight on May the 4th?