Gary Larsen's Bovine Farside Rocket - A BT-80H Scratch Build

[lakeroadster]

Here's the Farside cartoon:

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So can this rocket be made to fly? I took a quick look at it in OpenRocket.

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That huge front nose cone is wreaking havoc with the simulation. I guess a swing test of a mock up is in order?

 

[MarsLander]

Reel him in Frank, he bit!

 

[lakeroadster]

Reel him in Frank, he bit!

View attachment 636301

I felt compelled. Didn't want you to get all depressed.... :-(​

 

[MarsLander]

I felt compelled. Didn't want you to get all depressed.... :-(

When you dismissed it, I was crestfallen...I wanted a Bovine vs. Rocket Scientist drag race...or at least altitude contest...

BTW, you have MAD skeeeeeels...

 

[lakeroadster]

When you dismissed it, I was crestfallen...I wanted a Bovine vs. Rocket Scientist drag race...or at least altitude contest...

BTW, you have MAD skeeeeeels...

It's all good....​

 

[BABAR]

Here's the Farside cartoon:

View attachment 636295
​

So can this rocket be made to fly? I took a quick look at it in OpenRocket.

View attachment 636302View attachment 636303View attachment 636304​

That huge front nose cone is wreaking havoc with the simulation. I guess a swing test of a mock up is in order?

Udderly ridiculous!

 

[Daddyisabar]

You will have to hard input some base drag hacks behind that huge witches hat nose cone. Otherwise the sim is just sour milk. That computer machine will melt faster than ice cream in July.

Are we talking real aged barn wood planking? Real galvanized metal, silo top styled nose cone? Tiny hidden tractor motors?

 

[jqavins]

The nose cone of a rocket always tends to move the CP forward, so that sim might not be too far off. And that's without any base drag effect of the overhang pulling it further forward still.

 

[neil_w]

Nothing a little bit of depleted uranium in the nose can’t cure.

 

[Blast it Tom!]

Nothing a little bit of depleted uranium in the nose can’t cure.

Gee whiz, I laugh, but you're actually quite correct!

 

[lakeroadster]

Nothing a little bit of depleted uranium in the nose can’t cure.

I'll get in contact with Putin... He'll hook me up. He has more flexibility, since he just got re-elected.​

 

[Blast it Tom!]

I'll get in contact with Putin... He'll hook me up. He has more flexibility, since he just got re-elected.​

Ooooh, nice burn!

 

[lakeroadster]

Are we talking real aged barn wood planking? Real galvanized metal, silo top styled nose cone? Tiny hidden tractor motors?

A metal nose cone on a MPR? Oh, the horror. ​

You Sir have been reported to NAR Compliance, NARC for short. ​

 

[lakeroadster]

To demonstrate the impact of that huge nose cone I dropped the lower diameter of the cone down to 3"... and look at the stability difference.

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[jqavins]

Nothing a little bit of depleted uranium in the nose can’t cure.

Are you kidding? That stuff isn't even as dense than gold. What you really want is an osmium-iridium alloy. It's a little spendy, but might be easier to obtain.

 

[jqavins]

To demonstrate the impact of that huge nose cone I dropped the lower diameter of the cone down to 3"... and look at the stability difference.

View attachment 636354View attachment 636353​

So if you fudge a little - after all, measurements from a cartoon are not all that precise - you could reduce the cone's base diameter, and increase the body tube length. How much nose weight have you got in there? You could also raise the CG by building the fin can a little lighter; try "heck for sturdy" for a change.

 

[lakeroadster]

You will have to hard input some base drag hacks behind that huge witches hat nose cone. Otherwise the sim is just sour milk. That computer machine will melt faster than ice cream in July.

If I add a BDH behind the nose cone, it increases stability to 0.92 calibers. Again... a spin test is needed. ​

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[lakeroadster]

So if you fudge a little - after all, measurements from a cartoon are not all that precise - you could reduce the cone's base diameter, and increase the body tube length.

Sure, I could do that, but nope... not gonna do it. It's the principle of the thing. Make it to scale, or don't make it.​

Kind of like putting Lexan fins on a rocket... ​

How much nose weight have you got in there?

1" dia steel bar x 3-3/4" long, or about 13.4 ounces.​

You could also raise the CG by building the fin can a little lighter; try "heck for sturdy" for a change.

Design for Manufacturability... I already have the materials. Surface mounted 1/4" plywood fins, using the minimum diameter fin attachment method.​

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[BABAR]

You will have to hard input some base drag hacks behind that huge witches hat nose cone.

Is it still a BASE drag hack if it is the NOSE of the steed?

Does the FLARING of the structure affect the hack, as opposed to a cylindrical fat bottom rocket?

 

[BMcD]

Post removed.

 

[jqavins]

Sure, I could do that, but nope... not gonna do it. It's the principle of the thing. Make it to scale, or don't make it.​

Kind of like putting Lexan fins on a rocket... ​

Yes, I totally get that. I'm just saying that what scale is exactly, from a hand drawn cartoon panel, may be open to a little bit of "interpretation". I mean, if you squint, maybe you can take a quarter inch off here and add a half inch there. Every little bit helps.

On the serious side, I'm more than a little uneasy about the result of the base drag cone under the nose cone. Since that drag is acting on the base of the nose cone (up front) instead of the the base of the rocket (down back) I'm pretty sure it should have made matters worse, not better. The bottom line is, since you swing test everything, it's all academic.

 

[DirkTheDaring]

I would say that the problem is that your nose cone is too well centered, if you look at the cartoon, you’ll see it is quite far off center.

 

[lakeroadster]

I would say that the problem is that your nose cone is too well centered, if you look at the cartoon, you’ll see it is quite far off center.

Really.. well, I scaled it. Look at this:

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[lakeroadster]

Is it still a BASE drag hack if it is the NOSE of the steed?

Base of the nose cone... since it overhangs the body.​

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I'm simply looking at known tools that may help to explain a stability.​

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[OzHybrid]

Just hurry up and get it to the swing test and launch video. We all want to know whether to say "well done" or "I told you so" and although I'm betting on the latter, I'd like it to be the former.

 

[DirkTheDaring]

Really.. well, I scaled it. Look at this:

View attachment 636410​

Thanks, I can see it better now. I withdraw my suggestion.

 

[Daddyisabar]

All that base area under the cartoon nose cone is just screaming for some tiny plugged 13mm or micromax canted tractor motors if they could fit. AND, if it looks good with hiddenmotors, all problems solved. Turn those nasty vortices into lovely up front weight and thrust, both of whom are great friends of the silly oddroc flyer.

To quote from the Holy Grail: "and suddenly the animator suffered a fatal heart attack and the cartoon peril was no more." The quest to fly accurately proportioned cartoon rockets could continue.

 

[lakeroadster]

All that base area under the cartoon nose cone is just screaming for some tiny plugged 13mm or micromax canted tractor motors if they could fit. AND, if it looks good with hiddenmotors, all problems solved. Turn those nasty vortices into lovely up front weight and thrust, both of whom are great friends of the silly oddroc flyer.

To quote from the Holy Grail: "and suddenly the animator suffered a fatal heart attack and the cartoon peril was no more." The quest to fly accurately proportioned cartoon rockets could continue.

Heck, D motors would fit up there. Quan. (6), with an F-15 BP motor at the rear. But the altitude is only 255 feet.​

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Let me ponder the cost and complexity of this. Doesn't seem like a hill I want to climb.​

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And trying to get BP motors to fire at the same time as composite motors... very, very problematic​

 

[lakeroadster]

Wrong Thread... Moved to: Gary Larsen's Farside Rocket - A BT-80H Scratch Build

Nose Cone Repair​

The day after I turned the nose cone I noticed the crack was opening up... like considerably. I used a band clamp and clamped the bottom for 24 hours, periodically checking and re-tightening to close up the crack.​

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Then I applied wood glue and clamped it again. I'm pretty sure it's back to where it was when I initially turned the piece.​

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[Azamiryou]

I think this nose cone is for the other Larsen Rocket, isn't it?