Arapahoe-J - Successful L2 Cert!

Cl(VII) said:

Pusher! Enabler! Man who is almost certainly correct...with time though. That will come after a long burn K and a K boost-sustain flight. Believe it or not I have writen out plans for motor progression in each rocket. Found these bigger motors need more forethought and budgeting. Especially now that I have this guy who brings them right to the field.

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Totally can't wait to see the K375NW especially in this rocket.

So I loaded up all the recovery gear and electronics, and got the weight (8 lb, 13.25 oz) and CG sans motor, and put them in OR. I'm trying to decide what motor to load up for the maiden flight/cert flight. Below are the choices:

Notes:
- All simulations done with 10 mph wind.
- Assume 6 ft of rail guidance (7-8 will be closer to reality for the top button)
- Our waiver is 1 mile (5280 ft) AGL
- For 38 mm motors the altitude and stability will be slight over estimates as a 38-54 mm adapter will be required.

J350W (38-720), Apogee: 2530 ft, Stability (cal off rail): 1.64
J460T (54-852), Apogee: 3001 ft, Stability (cal off rail): 1.47
J275W (54-852), Apogee: 3029 ft, Stability (cal off rail): 1.30
J570W (38-1080), Apogee: 4096 ft, Stability (cal off rail): 1.62
J401FJ (54-1280), Apogee: 4369 ft, Stability (cal off rail): 1.39
J415W (54-1280), Apogee: 4600 ft, Stability (cal off rail): 0.99


I'm leaning toward the J570W. It gives nice altitude, high stability off the rail, and should be visually quite fun. The only problem is I don't have a lot of faith in the EZ reloads yet...too new. Alternatively, the J460T looks like the safest bet all around, but I'm not really a fan of Blue Thunder.

True last resort would be a J420R (38-720) I have awaiting pickup, but that is only a gentle stroll to 2291, but is quite stable off the rail (1.8 cal). Like I said, decisions, decisions...

EDIT: went with the J460T. Just the safest flight for the first flight.

SDRiegle

Sorry, don't know how to use this yet

Good luck on the L-2 flight !! I wish everyone could see this--it's just gorgeous!!!

hornet driver said:

Good luck on the L-2 flight !! I wish everyone could see this--it's just gorgeous!!!

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Thanks very much. It was good finally getting to meet you and see one of your creations in person.

Picture perfect day and flight yesterday for a successful L2 certification. Woohoo!

3031 ft on a J460T.

A few pics from the pad. This is why I don't prefer blue thunder, not enough effect. However, it does get the rocket moving NOW, which always makes me feel better on a first flight.

Beautiful! Congrats on L2. Now you put a K550 in it and let er rip

Sweet! Congrats on the cert!


TA

Congratulations. What a great design to do a cert on, and your build looks fantastic!

Cl(VII) said:

Picture perfect day and flight yesterday for a successful L2 certification. Woohoo!

3031 ft on a J460T.

A few pics from the pad. This is why I don't prefer blue thunder, not enough effect. However, it does get the rocket moving NOW, which always makes me feel better on a first flight.

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In person it seemed to have a much larger and brighter flame.

Congrats on the L2, Arapahoe's may just be one of the most beautiful and stylish rockets ever designed.

rharshberger said:

Congrats on the L2, Arapahoe's may just be one of the most beautiful and stylish rockets ever designed.

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X2 on both accounts.

Beautiful build, Nice Level 2 flight, Congratulations !:w:!

Thanks very much everyone. A particular thanks to Chuck (AlfaBrewer) as he has one of my witnesses on a really busy day. I don't think he touched anything of his until about 1 or 2 in the afternoon. He also helped me get thing on the rail, the strakes make it hard to see the buttons when holding the rocket from above.

I was telling Chuck while watching the rocket come down under drogue that I have never been very nervous for a flight, until this one. When that main inflated it was a great feeling.

I must also thank my recovery sidekick, my 6 year old son Wesley. This BAR thing started with a rocket for his 4th birthday, and almost 3 years later this...he and his little brother Casey are excellent enablers.

I am so glad you finally got to launch this bird. Unfortunately, the rest of us has yet to see how it flew. Did no one take a video? I was soooo hoping to see one. Nothing like seeing your scratch build fly like a dream and get a cert, to say the least.

Now I want to reflect on another Thrustline model that got brought up in this thread. I took the given information and did CAD drawings for a BT 60 model and a BT 70 model of the Duster. The BT 60 model comes out about 4' tall. The BT 70 model is a nice 5.5' tall model. This is a build that is only in the queue of possible builds, as I already have a plenty on my plate presently. I even dug up the old Plymouth Duster Logo (less the tornado cartoon character) as a possible decal. The pics below are the design and paint scheme concepts. Opinions?



The one on the right has a different font for the title.

Gary Byrum said:

I am so glad you finally got to launch this bird. Unfortunately, the rest of us has yet to see how it flew. Did no one take a video? I was soooo hoping to see one. Nothing like seeing your scratch build fly like a dream and get a cert, to say the least.

Now I want to reflect on another Thrustline model that got brought up in this thread. I took the given information and did CAD drawings for a BT 60 model and a BT 70 model of the Duster. The BT 60 model comes out about 4' tall. The BT 70 model is a nice 5.5' tall model. This is a build that is only in the queue of possible builds, as I already have a plenty on my plate presently. I even dug up the old Plymouth Duster Logo (less the tornado cartoon character) as a possible decal. The pics below are the design and paint scheme concepts. Opinions?

View attachment 259530

The one on the right has a different font for the title.

View attachment 259531

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There are a few videos that will filter to youtube in the next few days. I'll link them here when available.

As for the duster. When my current 38MD project is complete I will be starting a 2.1" Duster. I have black fiberglass sleeve for the tubing, and the fins will be CF over basswood. This is an attempt to make it look sweet and be tough enough for some aggressive flights. Of course, it will sport a 38 mm mount. It will probably be summer until this gets underway though. I have everything for the build, so you never know when I might get a build thread going.

Gary Byrum said:

Did no one take a video?

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Sadly my video camera was hijacked for an Easter egg hunt.

Congratulations on your L2. See you in a couple weeks.

First video, includes commentary from my wife Brandi, and youngest son Casey.

[video=youtube;bHUdmofn5IY]https://www.youtube.com/watch?v=bHUdmofn5IY&feature=youtu.be[/video]

Congratulations on the flight, sorry I missed it. I had committed me and my wife to babysit before the launch was announced and going to fly would have burned wife good-will I need for my L3. Anyway you do very pretty work.

qquake2k said:

Congrats on the L2! I love the blue flame on the blast deflector.

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It is cool. My favorite pic as I dug through my camera is the one below. I like the amorphous purple flame on startup. Matches the paint well.

AlfaBrewer said:

In person it seemed to have a much larger and brighter flame.

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I thought so too. The lack of blue in the pics may be a digital photography artifact. In any event, I was more than happy with the flight.

robertv2 said:

Congratulations on the flight, sorry I missed it. I had committed me and my wife to babysit before the launch was announced and going to fly would have burned wife good-will I need for my L3. Anyway you do very pretty work.

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No problem. Do not exhaust that good will. I want to see what you come up with for that L3.

Congratulations Chris on a super build and successful L2 flight! And thanks for posting your Youtube video.

Gary Byrum said:

This a great flying rocket. I have two now. Scratch builds of the original size and an upscale to BT-80. I just flew the upscale for the first time this past weekend and WOW! I opted for a different Phoenix design on the upscale, as I really didn't like the original. Don't forget to show us some build pics.

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Hi Gary,

Instead of buying a rocket kit that is L2 capable I was thinking of building one and I really like the Arapahoe design (have 2 in my build pile, just can't see to get caught up...). How do you go about upscaling a design? I've seen the little doohickies that increase the size of something as you trace them and I have RockSim on my other laptop (this is a Mac) that I haven't fooled around with but now that it's winter and my Rocket Lab (garage) is sooo cold.... Fin Wood type, nose cone, Any suggestions would be greatly appreciated.

Regards
Philip

You find, or make a sim (I prefer OpenRocket), then use the scaling tool to upscale (or downscale) the design. You then need to update your values to reflect the new materials (eg cardboard to bluetube, .050" cardstock to .25" birch ply, upscaled 24mm motor mount to your new diameter, etc.). From there, you make any new changes (payload bays, fin tabs, etc.) that the design requires.

Hmm... Where to find a sim?

I currently have a 3" in the works, using the BMS PNC-300K nosecone cutoff for the tailcone, and a Estes Big Daddy nosecone. The longer sloping tailcone is important to the look as is the shorter and fatter nosecone combo.

I have a 3" one that I just need to apply external fillets to the fins and it's ready to go. Made from bluetube, cut down fiberglass nosecone for the tail and 54mm motor mount. Should send it up next spring.