Falcon 9 - Has anybody played around with the computer models?

[Peartree]

Reading the threads about the Falcon 9 and the upcoming Falcon Heavy, and then looking at some of the F9 models being built started me wondering, how big would a model have to be to use a cluster of 9, 13mm, 18mm or 24mm motors and would a model that size be too heavy to fly on a cluster of that size?

I don't currently have any of the modeling software running but I know we have a few folk who build models like that for fun.

Have any of you tried this?

 

[LithosphereRocketry]

Reading the threads about the Falcon 9 and the upcoming Falcon Heavy, and then looking at some of the F9 models being built started me wondering, how big would a model have to be to use a cluster of 9, 13mm, 18mm or 24mm motors and would a model that size be too heavy to fly on a cluster of that size?

I don't currently have any of the modeling software running but I know we have a few folk who build models like that for fun.

Have any of you tried this?

Awhile ago someone was building a 9x24mm F9 cluster in the scratchbuilt section with hand-wrapped FG tubes. There hasn't been much done on the build lately- not sure why.

I don't think weight will actually be much of an issue- multiple motors add up fairly fast in terms of thrust: 9xA3 is a full D20, and fits in a 2" PSII tube. 9xC6 is a full F42, doable for a 3" PSII rocket if you build light. 9xE9 is a 50% H81- would be fine for a lightish paper 4" rocket. If you leave put the motor blocks you can put in G65s... Baby K582, plenty pretty much however you build it.

 

[dhbarr]

CTI g65 holding in 8x AT d2.3 in a bt80 (?) or 3in (!) gets my nod.

 

[Peartree]

Awhile ago someone was building a 9x24mm F9 cluster in the scratchbuilt section with hand-wrapped FG tubes. There hasn't been much done on the build lately- not sure why.

I don't think weight will actually be much of an issue- multiple motors add up fairly fast in terms of thrust: 9xA3 is a full D20, and fits in a 2" PSII tube. 9xC6 is a full F42, doable for a 3" PSII rocket if you build light. 9xE9 is a 50% H81- would be fine for a lightish paper 4" rocket. If you leave put the motor blocks you can put in G65s... Baby K582, plenty pretty much however you build it.

This sounds like fun. If I ever find the top of my workbench again, I may have to consider this seriously.

Thanks.

 

[LithosphereRocketry]

CTI g65 holding in 8x AT d2.3 in a bt80 (?) or 3in (!) gets my nod.

If you airstart them and cant them at 45ish degrees you can get a bit of overexpansion plume effect... You need a lot of BT space but it might be doable with smaller motors.

Starting around 1:50:
[video=youtube;r4XJS_oftH8]https://www.youtube.com/watch?v=r4XJS_oftH8[/video]

 

[Steve Shannon]

If you airstart them and cant them at 45ish degrees you can get a bit of overexpansion plume effect... You need a lot of BT space but it might be doable with smaller motors.

Starting around 1:50:
[video=youtube;r4XJS_oftH8]https://www.youtube.com/watch?v=r4XJS_oftH8[/video]

Of course, canting them like that costs 30% of the vertical thrust component also.

 

[LithosphereRocketry]

Of course, canting them like that costs 30% of the vertical thrust component also.

True- but D2.3s have barely any thrust anyway...

 

[dhbarr]

True- but D2.3s have barely any thrust anyway...

That initial thrust spike is 10N, always surprises me.

 

[markkoelsch]

Make it big. 9 54mm mounts. Make the out side ring if motors AT i65, and the central motors something higher thrust to get it moving. No motor tubes- just centering rings to cut down in weight.


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[dhbarr]

Make it big. 9 54mm mounts. Make the out side ring if motors AT i65, and the central motors something higher thrust to get it moving. No motor tubes- just centering rings to cut down in weight.


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L2050 you say? :-D

 

[LithosphereRocketry]

L2050 you say? :-D

Of course not! M1378, obviously!

 

[Nytrunner]

8 D2.3s? That's a big investment in 18RC hardware!

 

[Peartree]

So, at the scale sizes required for various motors, how tall would this model be?

 

[dhbarr]

8 D2.3s? That's a big investment in 18RC hardware!

You could do the c6's, just would have 2s thrust vs. 8 or so

 

[dhbarr]

So, at the scale sizes required for various motors, how tall would this model be?

For funsies, I whipped up an ultra-crude g65/d3.2 sim. That tells me it's got to be a 3incher, but it also opens up the possibility for a 29mm center core with 18mm outers. I get a length in the neighborhood of 1.5m OAL and about 1km for height, about 1kg MTOW. Did I mention this was a terrible sim?



Well can we do 13mm outers and keep it all LPR? Yup, about a meter long, about 54mm OD, flight of about 230m with d21 center and a3 outers.

 

[Peartree]

Cool!


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