Hello all I am interested in using the pirhana line cutter but I need to know how many grains it uses in triple 7 powder so I can get it passed by safety in my company. Does anyone actually know if not could someone measure? Thanks in advance.
The Piranha cutter uses the cavity in the base of the cutter to measure the minuscule pyro charge. No weighing of the pyro powder is necessary or advised as the actual weight of the pyro powder is different depending on which pyro powder you are using. In this case, Triple 7 in the 3f granulation, when using the cavity in the cutting piston as the powder measure, weighs about 1.2 grains, not grams but grains. As I said, Quite minuscule.Hello all I am interested in using the pirhana line cutter but I need to know how many grains it uses in triple 7 powder so I can get it passed by safety in my company. Does anyone actually know if not could someone measure? Thanks in advance.
Look again late this week or the first of next week...OT but speaking of the Tinder Rocketry Improved Pirhana Line Cutter ...
They've been out of stock for a while, does anyone know where I can buy a set ?
Thanks !
-- kjh
Still OOS as of today. Update to when back in stock?Look again late this week or the first of next week...
Hey William,Still OOS as of today. Update to when back in stock?
Thanks
William
Got it, thank you! Should ship today!Well, let's see if I can beat the geezers on this one. E-mail sent
Edit:
Thank you! If I could dump this head ache, I'd be good as gold!Thanks! Best wishes for a speedy recovery.
Hope you get to feeling better!Thank you! If I could dump this head ache, I'd be good as gold!
So...@Cameron Tinder --
I am about ready to start building Hedley Babar which is designed around a pair of your Improved Piranha Line Cutters.
Do you think they'll be available later this month ?
Thanks !
-- kjh
@jgarbus --So is the idea with the line cutter to throw out the entire recovery package at apogee and contain the main with the cutter?
Yes, with a little strain relief ( tape the ematch leads with a few humps so the shock cord takes the jerk.Do you just tape the ematch wire to the harness to keep them from getting tangled?
Never thought to compare it with a JLCR. That makes sense@jgarbus --
I am no expert -- in fact I'll be building my first HED rocket soon: It's Hedley, Hedley Babar !
But, yes, that is the general idea: kick out the main in a wrapped bundle, maybe along with a drogue and then use the line cutter to release the main at a reasonable altitude.
If you're familiar with the JLCR, it is conceptually the same idea except that the line cutter is fired by the main channel on a dual deployment altimeter / flight controller.
Yes, with a little strain relief ( tape the ematch leads with a few humps so the shock cord takes the jerk.
There are a lot of threads here on TRF with details and better explanations than I could provide
HTH
-- kjh
I had an arrangement to purchase a pair from someone, but after he accepted my offer, came back and told me that he sold them to someone else. Looks like I've missed out on my chance at getting a pair.So...
Another guy on this thread wrote to me wanting the last pair of Piranha cutters. I offered them to him but I mentioned that another guy on TRF also wanted a pair for a project that was fast approaching. When he found out it was you, he most graciously "bowed out" and has allowed me to offer them to you. (Thanks Stephen!) So, if you are interested, let me know here and send me your email address so I can get these out to you!
--Cameron
Cameron told me more are coming soon.I had an arrangement to purchase a pair from someone, but after he accepted my offer, came back and told me that he sold them to someone else. Looks like I've missed out on my chance at getting a pair.
I hope so.Cameron told me more are coming soon.
Hi Cameron, Had a chance to use the line cutters this last Saturday. One ground test and one flight test. Both worked great. However, I wrapped up the chute in a Nomex blanket held closed with a zip tie. At deployment I could see the cutter fire but the chute never came out from the "burrito". Upon examination, the cut portion of the zip tie was still wrapped around the nomex loosely preventing chute release? Additionally, when I cleaned the line cutter, a small piece of the zip tie had worked its way past the "piston" and was found in the lower part of the cutter. Is this normal??Hey William,
Production has begun, yet they are still not back in stock on the website and still may not be for another week.. I have been sick so I am moving quite slow. I have however finished 8 pair (4 kits) and am offering to those that ask. 1 set ships today. Send me an email if you are interested...
Hey William,Hi Cameron, Had a chance to use the line cutters this last Saturday. One ground test and one flight test. Both worked great. However, I wrapped up the chute in a Nomex blanket held closed with a zip tie. At deployment I could see the cutter fire but the chute never came out from the "burrito". Upon examination, the cut portion of the zip tie was still wrapped around the nomex loosely preventing chute release? Additionally, when I cleaned the line cutter, a small piece of the zip tie had worked its way past the "piston" and was found in the lower part of the cutter. Is this normal??
One last thing, what is the black cord, included in the box, intended for?
Great product thank you very much.
William
That is a VERY thoughtful change, @Cameron Tinder !Hey William,
When the cutter cuts the zip-tie or cord, it does indeed cut and stuff a portion of what the piston cuts into the cutter itself. This is normal and intended. The brown cord packaged with the Piranha cutter is waxed cotton cord intended to be used instead of the zip-ties. Unlike the nylon zip-ties, the cotton cord is quite bio-degradable. Also, when ingested by wildlife, cattle or horses, the cotton cord is a bit more digestible than the nylon zip-ties. This is especially important if you fly on grass or alfalfa fields that will be made into hay or fields that horses or cattle feed on. I changed this when it occurred to me how many of these zip-ties I was sending out in the kits and realized that a lot of flyers fly on these sorts of fields. I would hate to hear about the loss of livestock and quite possibly the loss of a launch site as a result of this sort of thing!
To be perfectly honest with you, I do not fly this way. It's either all out at the top (Low flying typically H motors) or tether and release, historically with the Tender Descender and now exclusively the bolted TD-2. So, really, I can only tell you what I THINK not what I have done in regards to using a "burrito wrapped" chute and a Piranha cutter to release it.That is a VERY thoughtful change, @Cameron Tinder !
I see in your Video: Improved Piranha Dual Mason Twine Constrained Parachute Simulation that you wrapped the chute + protector like an old-timey package and the twist passes thru the line cutter.
Is there any more to it than that ?
Thanks !
-- kjh
I have seen quite a few do it that way. That is a great way to have redundant with a cutter.Here's an example of a bundled main ready to insert into the upper end of the airframe with redundant Mako paracord cutters.
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