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Top Flight thin mil vs X chute

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BABAR

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I have an Interceptor E weighing in at 376 grams without motor, with stock 24” chute.
Did the Pursley skin thing and really want this back in one piece.
My field is about 300 yards square.

Any advantages of the thin mil over the X chute? I have been told I need a swivel for the X chute.

Was going to go with 36” chute. My recovery section is about 9” long by 2” diameter. Planning on e20-4 motor.
 

Mugs914

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I really like the X-form chutes myself. They pack easily, pack small and they will work fine without a swivel. Some say they drift less, but I can neither confirm nor deny that. Besides all that, they look cool! Top Flight does make X-form chutes in Thin Mil form. (I have quite a few of them. Good stuff!)

Based on the weight you posted, I think I would go with a 30"-36" X-form, or a 24"-30" conventional type. I'm afraid ~1 pound rocket under a 36" conventional chute could be in for a long ride with any kind of breeze. Of course a chute release changes that equation...

Edit to say that the recommended chute sizes should still bring you down pretty slowly; ~15fps or less.
 
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AfterBurners

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I really like the X-form chutes myself. They pack easily, pack small and they will work fine without a swivel. Some say they drift less, but I can neither confirm nor deny that. Besides all that, they look cool! Top Flight does make X-form chutes in Thin Mil form. (I have quite a few of them. Good stuff!)

Based on the weight you posted, I think I would go with a 30"-36" X-form, or a 24"-30" conventional type. I'm afraid ~1 pound rocket under a 36" conventional chute could be in for a long ride with any kind of breeze. Of course a chute release changes that equation...

Edit to say that the recommended chute sizes should still bring you down pretty slowly; ~15fps or less.
ditto
 

BABAR

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I really like the X-form chutes myself. They pack easily, pack small and they will work fine without a swivel. Some say they drift less, but I can neither confirm nor deny that. Besides all that, they look cool! Top Flight does make X-form chutes in Thin Mil form. (I have quite a few of them. Good stuff!)

Based on the weight you posted, I think I would go with a 30"-36" X-form, or a 24"-30" conventional type. I'm afraid ~1 pound rocket under a 36" conventional chute could be in for a long ride with any kind of breeze. Of course a chute release changes that equation...

Edit to say that the recommended chute sizes should still bring you down pretty slowly; ~15fps or less.
Size for size, are drag coefficients the same between standard and X chutes? I think that’s the right term, essentially is a 36” X chute going to be functionally equivalent to a thin mil or standard 36”?
 

teepot

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Size for size, are drag coefficients the same between standard and X chutes? I think that’s the right term, essentially is a 36” X chute going to be functionally equivalent to a thin mil or standard 36”?
No, you need a bigger x-form than a conventional chute. The x-forms don't sway like a regular chute. For 13.4 ounces you would need a 28 inch round chute, a 32 inch x-form or a 20 inch hemispherical chute. For a 15 fps descent.
 

RobertH3

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My "E" will be a 30" thin mil. The 24bit came with is a little undersized IMO. It went into the Goblin 4x24
 

Buckeye

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I assume the X form chute looks like an "X" or "cross?" Oddly, there is no picture on Topflight website.
 

BABAR

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Interesting

“Durable, Nylon X-Form Parachutes for Model and High-Power Rockets. Designed to reduce drift compared to standard parachutes.”

I always think of drift as being pretty much proportional to descent rate and wind speed. Is there something special about this chute that it provides relatively less lateral drift with the same descent rate? I.e. slows down the fall as well as other chutes but doesn’t drift as far?

Also saw this

The manufacturer recommends the use of a Swivel with the X-Form Parachutes. Use SW-225 up to SW-600 for the 30" size.

A guy from my club launched an Estes Pro series on an X without a swivel, perfect deployed chute started twisted and turned into a streamer. It wasn’t a pretty flight after that......

Are fishing swivels okay for these, or do I need something stronger?
 

neil_w

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Interesting

“Durable, Nylon X-Form Parachutes for Model and High-Power Rockets. Designed to reduce drift compared to standard parachutes.”

I always think of drift as being pretty much proportional to descent rate and wind speed. Is there something special about this chute that it provides relatively less lateral drift with the same descent rate? I.e. slows down the fall as well as other chutes but doesn’t drift as far?
This is an issue that has been debated here before. I believe it is correct that drift is proportion to descent rate and wind, period. What alternate parachute geometries can do, as far as I understand, is produce a more stable descent, with less rocking and swinging.
 

BABAR

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What alternate parachute geometries can do, as far as I understand, is produce a more stable descent, with less rocking and swinging.
As opposed to just using a bigger chute with a spill hole? I guess that’s a bit more challenging to do with a nylon chute than just cutting out the center of a plastic one.
 

neil_w

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As opposed to just using a bigger chute with a spill hole? I guess that’s a bit more challenging to do with a nylon chute than just cutting out the center of a plastic one.
Detailed performance comparison of different parachute geometries is above my pay grade. Heck, I mostly use plastic chutes with spill holes (never had one fail on me), and some thin-mill nylon.

I should mention (before someone else does) that there are obviously other benefits and drawbacks to different parachute types. Was just focusing on the question of drift for the moment.
 

Banzai88

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This is an issue that has been debated here before. I believe it is correct that drift is proportion to descent rate and wind, period.
Based on empirical evidence, and some simple math, most folks would agree with you. Anything that slows the descent rate necessarily increases descent time, and therefore drift regardless of the form factor. Stability, and drag, are functions of design and execution.

I find x form parachutes over rated, as they attempt to provide the stability of a larger parachute with spill hole in a different form factor.......and usually fall short of expectation, as they're especially prone to spiraling themselves up into streamers without a 'good' ball bearing swivel. Essentially an answer in search of a question that's better answered with a smaller parachute, or the same size parachute with a larger spill hole.

Yes, x form reduce drift over compared to the same size flat sheet without spill hole. BUT, in doing so, they INCREASE descent rate. If you're already at the high end of acceptable descent rate, a same size x form will only make things worse. If you go UP in x form size, you're back where you stared in descent rate, BUT you now have all the x form 'issues' inherent in the design.....and perhaps added bulk that you don't have physical room and/or newtons for.

Yes, x form may reduce swaying compared to the same size flat sheet without spill hole. BUT, in doing so, they are prone to rotating, and without a swivel are prone to rolling up the shrouds and acting like a streamer. They are also prone to causing the whole rocket to rotate, so if your fins are prone to damage 'swaying', they'll be put MORE at risk of damage twirling.

The answer to 'Should I use an x form?' is almost always answered with 'No, tune the parachute that gives you acceptable descent rate with spill hole size FIRST to prevent swaying. If you find you need more parachute to slow things down, go up one size, and continue tuning with spill hole size."
 
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crossfire

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Yes Xtype chutes are prone to rotate its because lines need to be tied off as equal as possible. That is why a swivel is recommend. If get lines tied equal a swivel is not needed.
 

crossfire

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I assume the X form chute looks like an "X" or "cross?" Oddly, there is no picture on Topflight website.
There is a XType picture on page showing XT sizes.
 
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