Cirrus Dart???? - Northern Colorado Rocketry

This topic has 41 replies, 7 voices, and was last updated 17 years, 7 months ago by Adrian.

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May 16, 2008 at 8:36 pm #40270
mule
Participant
Ok, you guys gotta stop me…. Smead, take the gun, Smead, take the gun. 😛 (if you haven’t seen Hook w/ Robin Williams – you won’t get that part)

So, I was getting a coupler and happened to look down and BANG. It grabbed me, well, Ok, I picked up the bag. A PML Cirrus Dart says the label. Not thinking, I bring it to the counter – as I’m replacing the newly dead servo on my RC Rock Crawler – I contemplate the purchase…. Luckily I put it back down and ran from the store – after paying for the servo…..

Now that dang thing has been calling to me. buy me, buy me…….
The lure is too great, h i g h a l t i t u d e (Homer Simpson drooling sounds) uhhhhhhhhhh.

SOOOO, tell me why I don’t need this…. Do not tell my wife….
Smead, TAKE THE GUN! 😛
May 16, 2008 at 8:43 pm #47998
new2hpr
Participant
It’s small and cheap for HPR (justification for the wife)

It won’t take up much room.

It won’t take too long to build.

Go on, buy it! You know you want to.

Just wait for the altitude junkies to chime in. I haven’t even broken a mile yet!

Ken
May 16, 2008 at 9:04 pm #47999
Anonymous
I say hitch up ‘yer skirt and buy that sucker (old NCR joke for those of you not familiar with the phrase! cross-dressing probably not really a good idea with this group – end of disclaimer).

Actually, DON’T buy the PML kit, but scratch build something better! By going scratch you can use a lighter, hollow nosecone and put a transmitter up there. You can also shorten the build and go higher than the PML kit would go on it’s own. The fins are also a bit larger than you might want to fly.

I flew “Beyond Consolation” at MHM. It is essentially a Cirrus Dart with the above modifcations. I got 13K on an I600. Chris LaPanse did pretty much the same thing, so phenolic will sure work.

For me, the most influential rocket I ever built was a PML “Nimbus” – from that I learned about minimum diameter, dual deploy, and fiberglassing all at once. The Cirrus Dart will open similar doors for those wanting to go really high – though I still say lose the solid nosecone and use smaller fins. If I can help you I am glad to do it. 14 of the last 15 rockets I have worked on have been minimum diameter (fin tabs seemed like a good idea on our “O” project).
May 16, 2008 at 10:20 pm #48000
Warren B. Musselman
Moderator
The next O project is going to be minimum diameter… hehe 😯
May 16, 2008 at 10:20 pm #48001
mule
Participant
Dual deploy on a min diameter….
you had me at dual deploy…..

I am a member of the mile high club with a single deploy L2 flight (7012′), that was what got me thinking about high altitude….

Humm, I do need a hollow nose cone anyway for my Beeline/Pico-P1 combo.

I’m not too up on scratch designs for high power, I’m still at work so I’m fumbling through this a bit.

So, if I use a 1.525″ tube, will the case slide in? What is the actual OD size on the 38mm case? I want to go with G10 fins or is that bad medicine? How about tubing? Filament wound fiberglass or phenolic with fiberglass? I’ve never seen a H.A. rocket up close and never been in a discussion on one.

I think I’ll set down with rocksim and plug in some designs this weekend…
May 17, 2008 at 1:35 am #48002
Warren B. Musselman
Moderator
I’ve done min diameter birds from 18mm up through 54mm so far. My preference is to work with FWFG (filament wound fiber glass), but that’s purely a labor convenience. On 29mm and 38mm you can definitely go with phenolic – even for a J350 or hotter so long as the airframe isn’t too long. Personally, I do everything with composites now – I have a helluva carbon over Estes paper tube airframe material for 24mm. The nice thing about FWFG is that finishing is a snap – a little wet sanding, probably no filling except where you’ve tip to tipped… easy and low labor by comparison.

Warren
May 17, 2008 at 4:14 am #48003
Ed Dawson
Don’t waste your time if the kit is the gray plastic, Quantum tube, version.

Like JW said, a scratch built is just as good if not better. For my SSSS bird, I started with the Cirrus Dart, but strayed a bit by cutting down the overall length and fins a bit. It’s also glassed phenolic. I’ve flown it once with the 5:1 conical cone from Performance Rocketry and once with their 6:1 version. Both have been fun flights the 6:1 shot went to 11,784 and 12,361 for the 5:1 (but I left a bit of the twist & tuck wires hanging out so I sure I could have gone higher.)

The reason I say this is that I’d strongly suggest you get the nosecone from Performance. You will DEFINITLY want to get that tracker in there for your for your shot.

G10 fins will be fine, and you probably want to lay in some glass in the fin root, or a tip to tip. On that small rocket you will likely sand through much of the glass at the tip & edges of your fins anyway.

No need to buy an expensive sheet of G10 when you only need a small amount. I’ve bought G10 in 4ft x 8ft sheets so I’d be glad to cut of a chunk for you for this project.

BTW, the altimeter was a PerfectFlite MAWD using the coin cell batteries.
May 17, 2008 at 1:49 pm #48004
Ed Dawson
Greg,

Do you notice how no one offered to take the gun away. Pretty much everyone one here would be handing you ammunition instead.

Tell your wife how much money you would save by scratch building. Yeah, that’s right…. your saving money….
May 17, 2008 at 2:14 pm #48005
mule
Participant
GEEEEE Thanks guys.
That dang guns a smoking right now. And to top it off I get a call from Jeremiah last night saying he’s got it on the brain too. Now I have to deal with HIS wife…..
Mine won’t really care, she thinks it interesting and the kids do too.

So, now to business.
I’m thinking the 1.525″ Phenolic and a 5:1 from GLR is a good place to start.

Recovery:
What about dual deploy? I’m assuming that is a must. I have a choice between an RRC2-mini and a Perfectflite Hi-Alt45k to choose from.

Tracking:
I have to take a picture of it, but I “removable” mounded the P1 to the mount on the Beeline and it is a nice compact design. But, I don’t need the P1 since both the computers log peak altitude. And I will save a tiny bit of weight and space…..

Time to get to work on the house, I have to head East today for work…
Greg
May 17, 2008 at 3:24 pm #48006
Anonymous
I’m thinking the 1.525″ Phenolic and a 5:1 from GLR is a good place to start.

Recovery:
What about dual deploy? I’m assuming that is a must. I have a choice between an RRC2-mini and a Perfectflite Hi-Alt45k to choose from.

Conical cones will do you better if you are really pushing things (which you are in this case). I don’t think G-Leap has conical cones? if not, http://www.performancerocketry.com

Given the outstanding recovery area, you can save an ematch and a couple inches in airframe (plus 0.2g of black powder!) by going with apogee deploy. I recovered from 13K at MHM on an apogee deploy. Note that I had a chute the size of an apple 😯 but that is why you build them tough.

Always — ALWAYS — check the CG/CP on these things. When you make shorter rockets with smaller fins, that can be an issue. Manageable, but an issue nonetheless. Be safe!
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