Falcon Heavy! BT60-based with separating boosters

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You guys may be all over this already, but I found the AXM paper model site with Falcon 9 models in 1:100 scale. Printing the patterns at 100/87.97 scale might be handy for body wraps, legs, and other fiddly bits. I have been beating my head against the monitor trying to CAD model some of this (the legs are crazy!!). Note the Falcon Heavy will use different grid fins--the larger titanium fins on the outboards, and the smaller aluminum (modeled in the link I provided) on the center core [I think I have that combination right...might be flipped from what I wrote]

EDIT: yep got it right! See photo I just attached....

FalconHeavy.jpg
 
You guys may be all over this already, but I found the AXM paper model site with Falcon 9 models in 1:100 scale. Printing the patterns at 100/87.97 scale might be handy for body wraps, legs, and other fiddly bits. I have been beating my head against the monitor trying to CAD model some of this (the legs are crazy!!). Note the Falcon Heavy will use different grid fins--the larger titanium fins on the outboards, and the smaller aluminum (modeled in the link I provided) on the center core [I think I have that combination right...might be flipped from what I wrote]

EDIT: yep got it right! See photo I just attached....

That's awesome! Thanks for that. I'll just scale it from 1:100 to what I need.
 
For the fins, I drilled five holes along the bottom. Two of these holes had dowels inserted to hold the stack straight while I sanded the edges even.




Then for each one I sanded along the bottom with 60 grit so the epoxy will have a better hold.




Taking burkefj's suggestion, I'm going to try half-slots on the fins and CRs so that they interlock. While being held straight with the dowels, I used the completed motor mount to mark exactly where the half-slots will go.




After lots of cutting with a hacksaw and some trimming with an x-acto...




Now, to measure(twice) the body tube slots and mark out where the CRs should line up. I took my time thinking this step through as once the body tube slots are cut, there's no going back.




Eight fin slots later... I used a metal ruler to help get the cuts as straight as I can. Looking back, I should have used my aluminum angle. Then I would be 100% sure the slots are cut perfectly parallel. These will have to be in the 99% close enough category.




Here I used each numbered fin to make some cuts into the black fiber CRs that they will go into so that it lines up perfect later when glued in.




After cutting slots in the CRs, I tried a test fit and everything fits really well at this point. I'm feeling confident this will be rock solid once complete. A bit overkill as well though, but that's OK.




And now the all-important dry fit. There will be a gap between the boosters and core once I build the attachment points though. That part will be next.

 
Imitation is the highest form of flattery. Build your own :)

Maybe after the Shuttle, Glen. I was looking at a BT80 design with BT100 fairing. Or BT70-BT80. I toyed with the idea of making a dreamchaser model for the top - but that's just silly. A FH could toss a dreamchaser to Mars - except the air's too thin to use it there. A simple F9 could handily get a dreamchaser to LEO. I suppose I could use my T344 and put a Dragon-for-people capsule on top - the translunar honeymoon cruise config.
 
Wow that must have been expensive. Three Falcon 9 kits put together it seems. As far as I know, you can only buy 1 at a time, so $30 plus shipping x 3 = $$$

Very cool nonetheless.

It wasn't mine, but I did rig the recovery for it a little over 2 years ago.

The kits were not obtained at market price, and there was no shipping needed. Call it creative use of intern perks.

We also knew nothing of cluster ignition, so that was a real fun launch attempt.

Yours will work better!
 
Any reason not to leave the noses on shock cords? I would think they would act like mini-streamers and improve the descent speed as well as being easier to find.

You can leave the nose on as long as the streamer slows the nose cone enough so nose falls slower than horizontal rocket body. If nose falls too fast will pull rocket body to vertical tail up position and you loose horizontal drag effect.
 
That looks nice and solid.

For the fins, I drilled five holes along the bottom. Two of these holes had dowels inserted to hold the stack straight while I sanded the edges even.




Then for each one I sanded along the bottom with 60 grit so the epoxy will have a better hold.




Taking burkefj's suggestion, I'm going to try half-slots on the fins and CRs so that they interlock. While being held straight with the dowels, I used the completed motor mount to mark exactly where the half-slots will go.




After lots of cutting with a hacksaw and some trimming with an x-acto...




Now, to measure(twice) the body tube slots and mark out where the CRs should line up. I took my time thinking this step through as once the body tube slots are cut, there's no going back.




Eight fin slots later... I used a metal ruler to help get the cuts as straight as I can. Looking back, I should have used my aluminum angle. Then I would be 100% sure the slots are cut perfectly parallel. These will have to be in the 99% close enough category.




Here I used each numbered fin to make some cuts into the black fiber CRs that they will go into so that it lines up perfect later when glued in.




After cutting slots in the CRs, I tried a test fit and everything fits really well at this point. I'm feeling confident this will be rock solid once complete. A bit overkill as well though, but that's OK.




And now the all-important dry fit. There will be a gap between the boosters and core once I build the attachment points though. That part will be next.

 
I've been splitting my rocketry time between this build and helping with the next OR release, so this build is going slowly so far. But that's OK, it's only February, no need to rush.

I decided to epoxy the fins to the motor mount before gluing in the mounts so that I can have better control over my attempt at making internal epoxy rivets. No better way to learn than to just try it. The end result are some very solid fins that aren't coming off any time soon.




One(well two) takeaway(s) from my first attempt at clear fins and epoxy rivets is(are): Drill smaller holes closer to the root. Having to use more epoxy to reach up to the large holes ends up adding weight. The other is that sanding down the fin edges even more with finer grit will result in a much cleaner appearance once done.
 
I've been splitting my rocketry time between this build and helping with the next OR release, so this build is going slowly so far. But that's OK, it's only February, no need to rush.

No could ever rush you. Heck, how long has the real one been "3 months out"? Lol
 
I started on the upper half tonight. First thing was to make the bulkhead for attaching the shock cord. I sandwiched together layers of balsa with a center fiberglass layer for ease of fabrication and strength, cut with a hole saw very easily. Total width is 1/2" (1/8+1/16+2oz+1/16+1/8). The eye bolt is bolted on and epoxied. I then sanded it a bit to fit inside the coupler.




I then epoxied the transition to the upper half of the core. The coupler with the bulkhead will go on the other end. This will separate in the same place as the real thing.




Same part as in the SpaceX Falcon 9 kit, the transition has this cross piece that I might use as a way to secure a removable payload section.

 
Last night I was pondering one of those with a little Starman inside and an 808 cam attached, let it loose with a parachute at apogee...
 
Now you need a Matchbox/Hot Wheels Tesla Roadster to go on top!

The prices seem to be coming back down, but on Tuesday the red ones jumped to $20+ after the livestream mentioned that the real Roadster had a Hot Wheels Roadster on the dash. I got mine for $0.99 plus shipping a couple weeks back, it's definitely worth it.

One thing to note is that it doesn't stick well to epoxy, so it has to be screwed in.
 
Imitation is the highest form of flattery. Build your own :)

I've got tubes ready and parts for ejection/side booster anchoring in hand for a 54mm version. It'll be HPR with electronic deployment of side boosters while the center is under thrust. Flies in 3 months plus a little bit. :)
 
Here is the upper section, which on the real rocket would be the 2nd stage + payload. The transition comes with a small 3/16" ring that would normally be used for a 3/16" rod, but on this model I think I'll have to go with 1/4" lugs due to the expected finished wight and thrust at liftoff.




Turned out good. I have no doubt that this won't be a failure point.




Recovery system for the boosters was next. I glued on a retaining ring that will hold dual 220# kevlar cords as a leader. Below the edge of the tube, they will tie off to a single 1/4" elastic cord. I want quite a bit of stretch since these will be deploying at high speed. I think I might build in some reinforcement into the top edge of the booster tubes since they will likely take some stress.

 
The motor mounts/fins have all been epoxied into their tubes. I still have to do some external fillets, however I'm going to wait on that until later. I'll make them very small since the fins are adequately held in underneath and fat epoxy fillets wouldn't look good with clear fins...

I spent a couple hours working out some details about the booster attachment points. The base(shorter one), is made from two strips of 3/32" balsa with a 1/8" short L-shaped piece in between. The booster(longer piece) is a strip of 1/8" balsa with a matching tab at the bottom. This is more or less the same principle as in Apogee's booster pod kit.




Here is a closer view of the little notch inside the slot that will hold the boosters in place.




I'm going to glue these parts on the core first, and then glue the booster's parts on after so that I can be sure to get a good fit and alignment.

 
I can post the .ork file late tonight, however it only works with one of the recent developer versions(17.11-rc2 or 18.01-rc3) and may need to be re-done when the next release is finally out to the public.

As for the booster separation mechanism, I'm going to try it with the same simple method as in Apogee's kit. Nose cone hook that releases on ejection.

As for the issue of booster separation and deployment at high speed, I'll have to check the sim plot for approx speed at that point and see what I can get away with. Last time I did separating boosters, they were built stout and had streamers. I would like them to come down on chutes this time if they can.

How do you get the developer versions? I want to do a high power 54mm main & 38mm boosters version of the Falcon Heavy.
 
How do you get the developer versions? I want to do a high power 54mm main & 38mm boosters version of the Falcon Heavy.

Being a contributor, I just build my own jar from the latest source. If you have some Java programming experience you could go to GitHub and pull the source and build your own custom version if you like. Otherwise later tonight I could probably post a dropbox link to a jar of the latest version, which at this point still has some wonky things going on so I would take sim results with a big grain of salt until the next version is actally released.
 
Thanks. I got the file downloaded. Haven’t fully got the sim completed but getting close. I need to figure out how the separating boosters will work in OR. Maybe it doesn’t in this development build. I’m not a programmer so I’ll just wait. This most likely won’t get built this year anyway. I design a lot of rockets and some never get built or they end up changing first.


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In 17.11, there is a built-in example. Go to File/Open Example/Parallel Staging Example. From that, you can highlight the Booster Set under Core Stage, click edit, then in the edit dialog under the Separation tab, you can select when the boosters separate.
 
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