This idiot just fried his TAC-1 chute!

[glenbo]

I feel like I deserve the idiot of the week award.

After wrestling with the inconsistancies with ground testing Pyrodex I finally get my hand on GOEX 4F black powder.
So back to ground testing again. The Talon 4 has approx 14 in. of space in the upper section to pack a main chute.
Since it weighs in at 12 lbs. fully loaded with engine and laundry I used a 60 IN. TAC-1 CHUTE. It does pack snug no matter how I
try but I used a kevlar protector that I burritoed the end of the chute with as well as a good hand full of dog barf against the top bulkhead.
1.5 grams pushed the nosecone out but didnt move the laundry. So I tried 2 grams and it fired perfectly! Until I saw my smouldering TAC 1
southern fried. The guys at Giant leap are giving me a break on the price of a new one & are downsizing to a 48 chute. What the hell did I do?
Thought I did everything right. I had a feeling about the chute being too snug but hey what do I know?

[Salvage-1]

Did you unfold the chute and shake it out fully after the first 1.5gram test? I have had embers from unsuccessful test lie around and do this. Now I take the whole thing apart and give it a damn good shake out before resetting the ground test.

Nice to hear that you are being looked after!

[glenbo]

Yup it was perfectly fine after the 1.5 gram test.

[CarVac]

I would use a Spherachute or something not TAC-1. TAC-1's are incredibly bulky for their size: a 48" Spherachute packs in 4 inches of 54mm tubing, and a 48" TAC-1 takes like 21 inches of the same tubing. Strong, yes, but the TAC-1 we have in my club is fraying, and it hasn't even been flown (because we don't have anything that it fits in!)

[llickteig1]

I use a kevlar/nomex protector or deployment bag on all my "nice" 'chutes. 'Chutes seem relatively expensive compared to a lot of the other components and I hate burning them.

If you're using dog barf, here are a few tips:
1) Make sure the charge is BELOW the level of the dog barf significantly. Having plenty of dog barf between the charge and the 'chute is critical - having dog barf around the charge doesn't help. The type of charge holder method you use will dictate how much. If you use a canister, the charge might be as much as 2" above bulkhead - this means more dog barf is needed.
2) Use plenty of dog barf. I usually aim for one full body diameter of dog barf above the charge. If you have space issues, IMO it is OK to pack down the dog barf and the charge will still pressurise the compartment and blow out the nosecone and 'chute.
3) If using kevlar recovery harness, put just enough dog barf into the BT to cover the charge, then most of the harness on top of the charge (the charge won't hurt the kevlar), then your full body diameter of dog barf, then the rest of the kevlar and the 'chute. This gets the 'chute as far away from the charge as possible.

Personally, in a 4" rocket I would start with 2 grams and possibly 2.5 depending upon if you use shear pins or not. Again, I'm really partial to nomex/kevlar protectors - burned 'chutes make me very sad.

--Lance.

[troj]

Again, I'm really partial to nomex/kevlar protectors - burned 'chutes make me very sad.

Not to mention that a $20 chute protector is way cheaper than an $80 parachute....

-Kevin (who needs to buy more chute protectors)

[glenbo]

Yeah no kidding! I am using a kevlar harness & chute protector.I could have used another handfull of dog barf. I believe what happened was
1. The parachute was right against the ejection canister despite the kevlar protector & dog barf due to lack of extra space or me not knowing how to pack a big chute in a small space.
2. The way I wraped the kevlar protector around the end of the chute facing the charge. There was blow by which means I need to use more caution next time.
Perhaps having the kevlar protector against the ejection charge rather than way up the harness cradeling the chute. What do you think? I am ordering a a 72 spherachute
as they pack so much nicer & will keep the 48 TAC 1 as a backup. Julie at Spherachutes is so nice to deal with! I highly recommend her company. Also an honorable mention to Giant Leap
for being understanding & helping me out on the price of another TAC 1.

[cwbullet]

Not to mention that a $20 chute protector is way cheaper than an $80 parachute....

Yup. I think several of use have learned this lesson. Some times dog barf is not enough

[llickteig1]

Yeah no kidding! I am using a kevlar harness & chute protector.I could have used another handfull of dog barf.

Maybe the TAC 'chute is just too bulky for you application. Those 'chutes are great, so save the replacement for another project and get as suggested get one that takes less volume.

I have packed some pretty bulky 'chutes in some pretty small spaces. I roll them up really tight and then burrito them in the protector - again rolling really tightly. Because of potential blow-by, keeping the protector up by the 'chute is better, IMO, and encasing the whole ''chute roll in the protector seems like the most effective protection. On 3" and 4" rockets I use the protector ONLY and no dog barf. My protectors are PLENTY big and can wrap up the 'chute and lines completely. Is your protector large enough? Put the harness in first (wrap it around your fingers to make a nice tight coil), drop it in on top of the charge, push it down witih a dowel or long screwdriver handle, add dog barf if desired, then put in your tightly wrapped 'chute and protector burrito.

If it comes down to trying to get 5 gallons of stuff in a 4 gallon space, a less voluminous 'chute may be your only real answer.

--Lance.

[troj]

FWIW, I think most vendors who sell chute protectors sell a protector that's too small for a given airframe -- it doesn't allow you to run the protection up high enough around the chute.

-Kevin

[dixontj93060]

I have pretty much quit using protectors/blankets. I bought Nomex cloth and make my own deployment bags. Much better protection and more reliable deployment.

[Adrian A]

[QUOTE=glenbo;354726
1.5 grams pushed the nosecone out but didnt move the laundry. So I tried 2 grams and it fired perfectly! Until I saw my smouldering TAC 1
southern fried. [/QUOTE]

This happens a lot. If you use a piston instead, it will protect your chute better, you need less BP, and it will be more reliable/repeatable than making your nosecone pull the chute out.

[glenbo]

Well now that I have 2 chutes coming my way lets hope one gets here before JULY 12 When I leave for LDRS. Things take a bit longer to arrive at the north side of the border although
there is a rush on both. I have run out of time to test ejection charges. 2 grams seemed to do it on the Talon 4 & if I use the 72 in. Spherachute it should come out even easier. Now for the Talon 3. Any idea what would be a good amount to start with for BP?It has only been tested with 1gram of PYRODEX which wasnt enough. Again I have just switched to 4f BP. It uses a 48 Spherachute which fits nicely. Neither of these rockets have flown yet so it is important to know the magic bp #

[donperry]

This happens a lot. If you use a piston instead, it will protect your chute better, you need less BP, and it will be more reliable/repeatable than making your nosecone pull the chute out.

X2 .

Sorry to hear about your accident. Try and see if you can make or purchase a piston then wrap your chute in nomex or even PAPER (brown paper, computer paper works).

I'm using PVC end cap as my piston in 54mm blueprint tubing.
1g violently ejects chute, drogue, nose and everything in between. Blow it apart or blow it up, they say.

[blackjack2564]

You don't mention what size Kevlar chute protector you use.
12 inch is usually recommended, but 18 is what does the job. Your chute should be totally wrapped by the burrito leaving nothing exposed to hot gases. If 18 won't cover the chute because it's too large then up size till one does or learn better folding technique .

[glenbo]

It was A 12 in. kevlar chute protector. It just covered 1/4 of the TAC 1. 18 in. would have been much better.

[glenbo]

Does an oversized charge usually do this if protected properly?

[blackjack2564]

Does an oversized charge usually do this if protected properly?

No, but you must completely protect the chute. Charge gases can blow right by the nomex/kevlar & into the chute when only partially covered as in your case. You can get away with it in smaller mid power rockets.

High Power all the "shortcuts" come back to bite you in the a$$.

Here is one of the many standard ways to burrito a chute. PUT the fully enclosed end in to the charge!


I have done this with chutes 20ft in diam.

For a 4in tube 12in protector is way too small. For me anyway.
This is a 12 in protector covering a 60 in chute in a 3in tube. BUT I can fold a chute very small!

[glenbo]

nice pics on that one. I need a bigger kevlar or nomax protector thats for sure!