x- 15 upscale driving me crazy

Hello just doing this for fun . May build later on but in OR it scales up nice . But the cp is in the nose cone . What a puzzle ,try adding mass didn't help . This is just for fun right now to many projects on the table

How big is it? I did one based on Apogee's Dynastar 66mm nose cone and tube. I imagine you are going for much bigger.

it's hard to tell what's wrong without the ork file.

Kevin

I think it was scale was 4" . Will post the Ork tonight when I get home . It maybe something I missed something

Make sure that the CP isn't set by the override value instead of being calculated.

Yes I will check that out this is the file I loaded to work on
Hostile_projectiles_delta_x15.rkt

It said weight over ride by stage . With a j335 ( I think.) It would appogee at 135 ft .way off

It always gives a low apogee for an unstable rocket, so that may be the issue since you describe the CP/CG being odd. Can you try to upload the file again, I only see a name, but it isn't a link that I can download. If I can download it tonight I'll have a look at it. I have made many a messed up OR file, so I have likely donw whatever is causing the issue with your file before.

I will post the file tonight . Thanks

View attachment hostile_projectiles_delta_x15.rkt
here is the or file for the x15 thanks chris

I played with this, problem appears to be that the strakes are too narrow to provide much stabilization. If you delete them the CP does move forward — right to the tip of the nose cone, which seems wrong to me. But they're not wide enough to move it back behind the CG. You have what amounts to almost a 2-fin rocket. Make the strakes wider at the aft end and the CP moves back quite a lot.

OK, I've been playing with the file and I noticed something strange. When you run the component analysis the stability tab shows that the wings are basically being ignored as evident by the CNa being 0. You can get this to increasde either by changing the wind direction toward 90 deg or by adjusting the Mach number way up, but these are artificial adjustments that do not persist when leaving the component analysis screen. When you are playing with them though you will see that the rocket becomes marginally stable.

Note: I played with the file before finding this, I merged the wings and strakes and did away with all the mass overrides, but I can't find a way to get OR to take the wings into account consistemtly, so I'm not uploading the working file as I have messed with quite a few things and wouldn;t want to introduce a mistake in case you build this.

Sorry, I couldn;t be more help, but perhaps someone knows what the magic setting for this is.

Good luck,
Chris

thanks i played with it took the aft to 6 inches . but the weight is still off . still saying over ride by stage , i have set compoent weight where they should be total weight should be around 10lbs but shows 23oz . dont know maybe i will get another file and see thanks for the help chris

thanks chris i am just playing with a delta wing . it for fun right now . i may reload the file at scale and see or just load anther plan file

I had a thought about how to trick OR on this one. Try rotating all fins and strakes 90 degrees from their current position. Don't do it on the slider on the side, but open each fin and rotate the possition by 90 deg. I'm not sure it will work, but I think it has a good chance.

I will try that . Also last night I loaded up the quest plans for there x 15 and scaled up to 4 inch . No problem .

If you decide to do a comparison of the two I would be interested to know what the difference that is leading to the issue is. Glad you have a good file now though.