BOOM XB-1

[neil_w]

Oof, that looks like when I came back to my Ragnarok and found all the cuffs on the wings looking like.... well, like that. Good luck with the glue, and get a whole mess of pictures before and during the flight(s)!

 

[jqavins]

Oh, man, now I regret suggesting tape. Sorry.

 

[mbeels]

Oh, man, now I regret suggesting tape. Sorry.

No, I think it was a good idea. Definitely easier than masking and painting. The tape worked fine on the leading edges of the horizontal stabilizers. I think that the issue with the vertical stabilizer is that I had to clear coat it after I applied the water transfer decal (it was fragile). And for whatever reason this tape doesn't stick as well to the clear coat, as it did to the flat black paint. I don't know why. I also clear coated over those tape strips on the horizontal stab, so maybe that is helping to hold it down.

 

[mbeels]

The XB-1 "flew" today at MDRA on a D24. Recovery was good, although it ejected my 18/20 motor case, so that's gone. But flight was... well... watch:

 

[neil_w]

There's so much asymmetry in the design, I don't know how you begin to diagnose what is happening. But it went up and came down in one piece, so it is now officially a rocket.

 

[mbeels]

Yeah, this rocket has literally no straight lines or flat surfaces, so probably the airfoil shape came out differently on each wing or something like that. It would have been really easy to get something out of alignment. It did more "flying" than a ballistic trajectory, I guess it is an airplane after all. But I beat Boom to get it in the air .

And thanks to Tom for the photos!

 

[H. Craig Miller]

That is an amazing build... I can’t believe the construction skill and finish detail...

I like the “Cheaper Than Dirt” stealth rocket on the far right too.

 

[Senior Space Cadet]

It started with neil_w's "imagination fuel" post, it got me firing on all cylinders, so to speak. I really love airplanes that look like rockets, and rockets that look like airplanes. As he observed:



and that challenge makes these candidates for an even more fun scratch built project. I started thinking about how to get away from cylinders and recreate the look of some of these exotic shapes. There is a lot that can be done with cylinders and planes (such as @lakeroadster 's slick F-79 Lone Wolf) , but I wanted to do some compound curves.

There are quite a few nice examples of non-cylindrical rockets here on TRF, such as @jqavins Elliptical Rocket, @boatgeek Spruce Goose, the current Steamship Barbicane build by @Ted Cochran , and I'm sure there are more. So this is nothing new, just my attempt at it.

View attachment 421157

This appears to be a concept image of a supersonic jet that is currently in production. There is a website with photos of the current progress as well as some descriptions and a 3D model:

https://boomsupersonic.com/xb-1/
The XB-1 will be a demonstration plane for their future Mach 2+ commercial jet liner ("Overture"), but it looks like a fun build. I don't expect this will be a quick build, there will be some experimentation along the way.

I really like the look of the XB-1.
The XB-1 looks like it has three engines and most fighters have two, I have to figure out what can be done on Open Rocket.
I'm trying to keep the build simple, but having genuine air intakes and two engines would be cool.

 

[Senior Space Cadet]

I turned off the scroll saw, put down the X-acto knife, and stepped away from the work bench.

Instead, I needed to sit down at the computer and come up with a plan. Between the website and 3D model, I picked out some views that would be helpful for getting more careful measurements.

View attachment 421293

With GIMP, I scaled a top view and side view to match, and then used the measure tool to get dimensions in units of pixels. Then I played with the scaling to figure out what size I wanted.

View attachment 421294

I placed purple lines on the side view where I'm going to put bulkheads. The forward most section will be a solid balsa nose cone, and behind that will be a BT-55 stuffer tube transitioning to BT-20 at the tail cone.

I then used the 3D model to infer what the cross section shape looked like, and sketched those shapes in boxes drawn to the dimensions I determined. That sets the height and width of each station.

View attachment 421295

I cut out half of the shape, and used that to get symmetric bulkheads drawn on 1/8" plywood by flipping it over a centerline.

View attachment 421296

Then I traced out a BT-55 hole through the middle, and cut them out on a scroll saw.

View attachment 421297

Ok. This seems more promising.

Ah, so some of you do use scroll saws! Something I'm considering buying.

 

[Senior Space Cadet]

Not particularly, I have a long, wide aluminum straight edge, and press it down firmly on the balsa sheet with one hand, and cut with a sharp #11 blade using the other hand. This particular sheet of balsa is particularly light and soft, so it is cutting very smoothly and easily. Some of the harder sheets tend to pull the blade with the grain, but this sheet isn't doing that.



With the strip laying on the surface, I'm using a pencil point to approximately mark the intersections with the adjacent plank, slicing it off with a sharp blade, trimming if necessary, and then counting on some sanding and filler to cover everything up . The last piece in a section take the most time, it has to wedge against the top and bottom plank. So it takes some fiddling with a blade and swipes of sandpaper. There will be some sanding. Ok, there will be a lot of sanding. I'm starting at a corner (the bottom edge has a pretty well defined corner), and working towards the centers. More photos tonight.

I bought a little gadget for cutting strips, called a Balsa Stripper. I don't know how they came up with that name.

 

[Senior Space Cadet]

You guys are making me feel really inadequate again. Thank god it's only rockets and not something else.
I've got to kick up my building skills and figure out how to download Rocksim.
I'm looking forward to seeing finished builds and I need to get cracking on mine.

 

[BABAR]

The XB-1 "flew" today at MDRA on a D24. Recovery was good, although it ejected my 18/20 motor case, so that's gone. But flight was... well... watch:

Somehow I missed this when it came out.

Congrats on multiple successful flights. I went to NSL in 2019, brought a bunch of LPR rockets. The ROC guys were great, although the event caters to HPR. Not being a HPR guy, I am afraid after the first 40 HPR launches, it seemed to me that if it wasn’t your rocket or someone you knew, it got kind of redundant (although the HPR rocket that did a full loop at about 150 feet got just about EVERYONE’S attention! I think it was on an M motor)

For a sport rocket where you just want to see it fly and recover it intact, a little bit of a squirrel when the rocket is NOT a typical 3FNC is okay and even kind of fun, as long as net trajectory is vertical, ejection close to Apogee, and rocket recovers safely and preferably close by. I’d say you chalked up a huge win, the slightly less than nominal flight was like icing on the cake of a FAR from nominal rocket!

Ironically it was Bare Metal (which looks like a great paint job on a slick but pretty pretty straight forward symmetrical rocket) that tried to sign your name in the sky on its gazillion and first flight!

 

[mbeels]

For a sport rocket where you just want to see it fly and recover it intact, a little bit of a squirrel when the rocket is NOT a typical 3FNC is okay and even kind of fun, as long as net trajectory is vertical, ejection close to Apogee, and rocket recovers safely and preferably close by. I’d say you chalked up a huge win, the slightly less than nominal flight was like icing on the cake of a FAR from nominal rocket!

Thanks! It felt like a less-than successful day, given the number of flights I had do odd things. But I think you're right, although slightly unpredictable and surprising, it was basically a safe flight, and good recovery. Definitely exciting to watch.

Ironically it was Bare Metal (which looks like a great paint job on a slick but pretty pretty straight forward symmetrical rocket) that tried to sign your name in the sky on its gazillion and first flight!

I know, that surprised me. I think that is the first time I've had a rocket go skywriting like that. It's a pretty simple design. I think I'll retire this booster section (it's getting worn out and ragged anyway, and the shock cord needs replacing), and rebuild it with 4 fins (instead of 3).

 

[BABAR]

Thanks! It felt like a less-than successful day, given the number of flights I had do odd things. But I think you're right, although slightly unpredictable and surprising, it was basically a safe flight, and good recovery. Definitely exciting to watch.



I know, that surprised me. I think that is the first time I've had a rocket go skywriting like that. It's a pretty simple design. I think I'll retire this booster section (it's getting worn out and ragged anyway, and the shock cord needs replacing), and rebuild it with 4 fins (instead of 3).

Also ironically your best pic included a pencil rocket.
Great to see and hear you end your son enjoying being together at the launch. Savor every moment, they grow up waaaay too fast.

 

[Daddyisabar]

Airplane rockets rule!

 

[jqavins]

Ironically it was Bare Metal (which looks like a great paint job on a slick but pretty pretty straight forward symmetrical rocket) that tried to sign your name in the sky on its gazillion and first flight!

I know, that surprised me. I think that is the first time I've had a rocket go skywriting like that. It's a pretty simple design. I think I'll retire this booster section (it's getting worn out and ragged anyway, and the shock cord needs replacing), and rebuild it with 4 fins (instead of 3).

My first such experience was with a mid-power 3FNC that I had built stock from a kit very well and solitly, and had been checked and endorsed by the very experien ed RSO. It should have been a perfect launch, but it went skywriting and "landed" hard under power. The concensus on the field was that the issue was with the motor, the nozzle either defective or partially blocked. All of which I mention because it may be the same issue is what bit you.

(It's a tough rocket. The damage was minor and has been repaired. But the finish will never be the same.)

 

[mbeels]

Also ironically your best pic included a pencil rocket.
Great to see and hear you end your son enjoying being together at the launch. Savor every moment, they grow up waaaay too fast.

Oh hey! Thanks for posting that photo, I really like it and had almost forgotten about it. Good to see it again. Yeah, we're having fun, and you're right, it seems to be going by too quickly. His enthusiasm is contagious and it helps get me going each day.

The concensus on the field was that the issue was with the motor, the nozzle either defective or partially blocked. All of which I mention because it may be the same issue is what bit you.

Ah, I should have kept the nozzle for that motor, someone else mentioned the same thing and I forgot to check it out.

 

[jqavins]

It might be worth giving the rocket another chance as is. Just pick an engine that keeps it low and fly on a grass field.

 

[BABAR]

My first such experience was with a mid-power 3FNC that I had built stock from a kit very well and solitly, and had been checked and endorsed by the very experien ed RSO. It should have been a perfect launch, but it went skywriting and "landed" hard under power.......The damage was minor and has been repaired. But the finish will never be the same.)

Hence the adage, “The probability of a rough landing is proportional to the effort spent finishing it, squared” (roughly )

 

[jqavins]

Doesn't that mean that after enough effort is put into finishing, the probabilityof a hard landing will exceed 1? (The answer is yes, it does.)

Perhaps the probablility of not experiencing a hard landing inversely proportional to the effort. That way it asympotically approaches zero.

 

[Ronz Rocketz]

If you integrate the derivative for the area under the curve as x approaches infinity, then you're effed.

 

[boatgeek]

Hence the adage, “The probability of a rough landing is proportional to the effort spent finishing it, squared” (roughly )

I don’t paint badly, I ensure safe flights!

 

[BABAR]

Doesn't that mean that after enough effort is put into finishing, the probabilityof a hard landing will exceed 1? (The answer is yes, it does.)

Perhaps the probablility of not experiencing a hard landing inversely proportional to the effort. That way it asympotically approaches zero.

In the extreme example, definitely true. If no time is spent in building the rocket, it will never land and never be damaged. (In fact, it will never be built or launched. In case someone claims the rule is violated by RTF rockets, even if BUYER didn’t put any effort to finish it, the manufacturer put in at least MINIMAL time )

 

[mbeels]

Make sure you tweet your model build to Boom .

Hey this is cool, checkout Boom's Twitter and Facebook page:



https://www.facebook.com/boomsupersonic

 

[Nytrunner]

Thats great PR! Not onky did they help provide info for your build, they share and displayed your work too!

 

[neil_w]

Hey this is cool, checkout Boom's Twitter and Facebook page:

Outstanding!

That model is worthy of recognition for sure.

 

[kuririn]

Way to go Marten!

 

[Mugs914]

That is awesome Marten!!!!!

(Not to mention well deserved!)

 

[lakeroadster]

Every time I see a photo of Boom XB-1 I think... man... what an awesome rocket.

Congrat's Marten.

 

[mooffle]

I know you were concerned about the flight profile but they thought the flight was awesome enough to share on their official twitter. Kudos