Mac Performance Arcas 3"

Build pics so far

Interesting idea for the fillets.

Glad to see someone else uses the ole Bob Smith besides me.

Switch in, ebay done need to make sled in nosecone for eggfinder and lastly paint

Interesting way of mounting the 9V battery. I've always done mine with the terminals UP. Is there a reason for mounting it sideways?

Also, I don't recognize the brand, is that a rechargeable? Did that play into your choice of mounting positions?

No particular reason for the way I mounted the battery, and the battey is a Duracell procell and I believe that's a newer version of the copper top.

Rafael said:

No particular reason for the way I mounted the battery, and the battery is a Duracell procell and I believe that's a newer version of the copper top.

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Do they still use the soldered internal connection like the Copper Top? That has been the only 9V I've used because of that.

Yes, from what I have read they are the same but packaged in bulk for the medical field. My wife works for IT at the hospital and that's where she grabbed them for me.

Ready for first coat of primer


First coat done

Arcas stickers from Stickershock will be here Thursday so hopefully will be done by then.

Just got a gift in the mail. Fast service from Stickershock!! Thanks Mark
Drogue chute done, Mom working on main.

Rafael said:

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Just got a gift in the mail. Fast service from Stickershock!! Thanks Mark
Drogue chute done, Mom working on main.

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Wow,,
No kiddin,,
Your mom makes a really nice chute...
My compliments....

Teddy

Good looking build. I've always liked the Arcas. My offer to help still stands. Good luck on it's maiden flight. Oz

Main chute done just need to sew on the shroud lines. I know Mike from Mac Performance told me to go 36" but wanted a slower rate for main so I went 46" and gonna put 12 shroud lines instead of 6

ozwald said:

Good looking build. I've always liked the Arcas. My offer to help still stands. Good luck on it's maiden flight. Oz

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I am definitely going to have questions for you soon. I am going to need help ground testing charges.

paint and vinyl complete.

That looks awesome, great job Rafael!

Rafael said:

View attachment 265749View attachment 265750View attachment 265751Switch in, ebay done need to make sled in nosecone for eggfinder and lastly paint

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Do yourself a favour and scrap the 9v alkaline on your StratoLoggerCF, and go with a 1S Li-Po. It is a better choice and arguably more reliable in your case with the added resistance within your deployment charge harness from the terminal blocks on the altimeter to the terminals on your doghouse charge wells.

I run the StratoLogger SL100 and CF with 1S 350mAh Li-Pos, even though you could get away with lower mAh. The specs on the altimeter are from 4-16 volts and as you may or may not know a 1S Li-Po is 3.7 volts, but that is with less than 50% charge. Fully charged they are 4.2 volts and due to their lower internal resistance you will get much more amperage from them, less discharge when storing them and much faster recovery times between the channel firings.

I had a StratoLogger SL100 fail due to a combination of higher than desired resistance in the wiring using a 9v battery. Since then I upped the gauge of my wiring harnesses to 20 gauge and use Li-Pos exclusively. I have also conducted many back to back bench tests, at this stage, firing dual e-matches per channel within a second or so of each other, with 0 failures. Also the StratoLogger allows you to download the data from the flights, one monitored parameter is the voltage based on the time-line @ 20 samples per second. When I look at my logs the voltage does not drop at all after events. I have seen the same logs for 9v batteries and in many cases you can see a voltage drop immediately.

One thing to be careful of, the SLCF has a 5 amp per channel max current rating, see the following thread I created a while back. Specifically read Bob Krech's response in regards to using Li-Po vs alkaline battery chemistry. https://www.rocketryforum.com/showt...to-terminal-blocks-but-do-direct-on-altimeter