Interceptor-M with Booster

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PunkRocketScience

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Over the last couple of months, I have talked some tall tales about the group project for DART and TRASD for Plaster Blaster 2008.

Now, it's time to put our collective money where my mouth is!:D

We have had our first planning meeting and will be having another this coming Saturday to start to nail down some definite details.

We are working on the premise that our main airframe will be a 10.5" OD sonotube, which gives us an upscale factor of 7.92. The booster airframe is either going to be 10.5" or 12.5", depending on whether or not we can fit the 12.5" tube between the lower fins.

I'm posting a PDF from the initial CAD drawings.

View attachment Upscale Interceptor_7.92x.pdf
 
Okay, here's my first pass on the Rocksim file... I installed 3 Pro54 6 grain XL (L730) motors in the main and 3 Pro 54 6 grain standard (K660) in the booster. Not sure off the top of my head without doing the math if that really comes in in the M range, but that will be what we get it trimmed out to for the final flight.

Any of the Rocksim masters out there, feel free to tweak the file for better appearance or flight accuracy.... :D

View attachment 7.92x Upscale Interceptor.rkt
 
Nice! The 12.5" will fit. 15,600Ns by my calculation (mid-size N). Where are the build pictures?;)
 
Oh come on now Guy, you know very well there aint' gonna be no "N" at PB.

Would be nice though huh... I've got an "N" casing that will never see that launch site.. it's really too bad.

Brent
 
Nice! The 12.5" will fit. 15,600Ns by my calculation (mid-size N). Where are the build pictures?;)

Hey Guy-

Ummm... Yeah... Give me a few of weeks and we will probably have some pics for you... How is the Pleiades coming? I haven't even seen design calcs yet...

Okay, so I might have overshot on the power a little... Guess we'll have to trim the booster back a bit... :cry:
 
I have a 4x testbed (proof of concept) in work. The booster is almost ready for paint and the sustainer is still in subassemblies. The first test flight for electronics and system integration is slated for the SSS March launch. First flight will be 3 H242T's in the booster and a J90 in the sustainer. The team is still debating participation since big-build burnout is setting in along with individual projects each member is pursuing this year absorbing a fair amount of time. Ask me in May.
 
You may (or may not) know that you will need to calc a three-axis center of gravity for this project to make sure that the thrust vectors for your motors all pass straight through. The lower motor will need to be tilted to achieve this alignment.

If the motors are each simply pointed straight forward, then the net thrust force (from the combined upper and lower motors) will very likely be offset underneath the vehicle c.g.
If you have enough fin area you may get away with mis-aligned thrust but you will probably have a pretty swervy flightpath. The rocket may curve over and go "cruise missile" or may even impact at/near deployment time.
If you don't have enough fin area you will probably end up with a flying (briefly) pinwheel.

Do your math, and have fun with the project!
 
Powderburner - the USS Pleiades does not have an offset booster so it does not have that issue. Other challenges abound in the build and system integration, however.

Todd - I thought the CA limits were M for single motor and N for clusters and/or staging? And Powderburner does bring up an issue that needs to be considered and accounted for if necessary with the offset booster in the Interceptor.
 
Okay, Okay Todd,

I attached the 4x Pleiades rocksim. The actual booster weight is about 4 oz heavier due in part to the 3 layers of heavy glass I added to the coupler section (needed to deal with engine out loads just in case one or two motors fail to light in the cluster).

View attachment pleiades-4x-long-booster.rkt
 
It may be my mis-understanding, but I thought that TRA chastised Andy for exceeding the full M limit with his cluster?

Brent
 
It may be my mis-understanding, but I thought that TRA chastised Andy for exceeding the full M limit with his cluster?

Brent

You understand VERY correctly. The last time I talked to him he was understandably really upset about it still. I hope that the TRA board realizes what an asset that they have lost.

But, that being said, please let's not let this thread turn into a discussion of the X-wing fiasco...

Powderburner-

Thanks for the info. I have not done anything remotely on this scale before and wil not turn away any reasonable advice! I'm more than big enough to realize that this is a group effort, whether or not people are working directly on the airframe or not!
 
Todd

Looks like a neat project!! Let me know when the build sessions are and I will try to make it down. I will also donate some $$$ when you are ready but lets talk about that off line.

I can hardly wait until PB. I am glad that you stepped up to lead this years special project!!!
 
It may be my mis-understanding, but I thought that TRA chastised Andy for exceeding the full M limit with his cluster?

Brent
Not quite right. A full 'M' is 10,240 N.S., the California limit is 20,480 N.S., or a full 'N'.
 
Ken,
Then why aren't we allowed to launch "N" class motors at PB?

I know it's not a TRA thing as people launch "N"'s everywhere else.

Or does it go back to what Guy said about the rules in CA. being no single "N"'s but a "N" cluster is allowed?

Brent
 
Or does it go back to what Guy said about the rules in CA. being no single "N"'s but a "N" cluster is allowed?

Brent

Yes. I have no idea who made the law, or who to talk to about it but I'd like to get it changed somehow. It's a nonsense rule to begin with.

OK, back to our regularly scheduled ON TOPIC build thread!

Nice concept guys! This looks like it's gonna be another fun PRS project!
 
Okay, Okay Todd,

I attached the 4x Pleiades rocksim. The actual booster weight is about 4 oz heavier due in part to the 3 layers of heavy glass I added to the coupler section (needed to deal with engine out loads just in case one or two motors fail to light in the cluster).


Wow, Guy, that's gonna be awesome as well!
 
Nice concept guys! This looks like it's gonna be another fun PRS project!

This one isn't just PRS, it's for DART and TRASD... The more the merrier! While you are at the wrong end of San Diego, you are more than welcome to come and filll and sand fiberglass tube... We're gonna have a lot of it...
 
The 4x Pleiades will definitely be at this next PB. In all likelyhood the 8x will not be ready for this next PB - but it will fly when it is ready.
 
Todd

I just sent you an E-mail. You going to Plaster City this weekend. Jonathan and I started prepping the THOR tonight. We can hardly wait!!

We are hoping to see your level 3 attempt!!

Lee
 
Todd, L3 attempt this weekend? SWEET!

I have a buddy who is gonna attempt his L1.

Lee- Whatcha flying the Thor on? I think I'll be there for Saturday only, depending on if I can shake this friggin flu or not.
 
Look forward to seeing you. I am bring plenty of food and a few adult beverages. Hopefully you will stay for awhile on Saturday night and have some.

I hope Todd will launch his level 3. I think he has had plenty of time to go through his check list a few 1000 times!!

We are planning on launching it on a K1275R and then air start 3 - J400ss. Should be fun. I am hoping to get everything ready at home so we can sit back and relax at the launch.

Are you going to bring anything?

Hopefully Todd wil jump in here soon!!
 
Hey guys... Just sent Lee an e-mail...

Unfortunately, I'm swamped with stuff to do this weekend (and for the next month... If you want the gorey detail, PM me, but you probably don't want to know...) so I'm not going to make the launch. I'm gonna shoot for March for the L3. Hopefully the weather will hold off for me to run my checklist the prescribed 1000 times... ;) Fat Tires all around if I make it!
 
WOW!! I am on the wrong side of the country apparently.......this is SWEET!! I am STILL *rolls eyes* working on my Interceptor G, strengthening the fins, improving the recovery system, etc..... Even that has proven to be quite a project.....but, this....this REALLY is great! Do us all a favor though, post up the flight video whenever that takes place!!

Thanx,
spacemonkey )O(
 
Hey SpaceMonkey-

Welcome to TRF! I'm sure that there will be PLENTY of video (including on board), but the flight won't happen until October. Stay tuned for updates...
 
Todd,

Extra credit if you build the entire thing from pieces from the EMRR Box-o-parts competition;)
 
Thanx for the welcome! I will be honest.....I LURK!!! *grins* I guess I just had to say something finally! See ya around!!

spacemonkey )O(
 
Todd,
Got the T-H cam today, it’s friggin' awesome. It uses a standard SD card expandable memory so no need to start the camera at the last min. Just pop a 1Gig in there and leter' run. I'll bring it to the next DART launch so you can check it out.
 
So do we shoot the video looking up from the bottom or down from the top? Either way it will add some sweet shots!
 
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