what is difference between these parachutes

[yucel]

hello everyone

we will buy a parachute but we are undecided between two parachutes.

first one is this parachute
https://www.apogeerockets.com/Build...rachutes/High_Power/72in_Iris_Ultra_Parachute

second one is this
https://www.csrocketry.com/recovery...standard-parachutes/70in-topflight-chute.html

first one is heavy and expensive why? what is difference?
does anyone use the Top Flight Recovery is it safe we will buy this item from turkey is there any problem about shippment?

thank you.

 

[Bat-mite]

Iris Ultra is made by Fruity Chutes. It is designed to give a high coefficient of drag but pack in a smaller space. Top Flight Recovery chutes are very good and not as expensive. Send an PM to pnobile here on TRF. He owns Top Flight.

 

[yucel]

Iris Ultra is made by Fruity Chutes. It is designed to give a high coefficient of drag but pack in a smaller space. Top Flight Recovery chutes are very good and not as expensive. Send an PM to pnobile here on TRF. He owns Top Flight.

thank you for your answer and advices i will send pm now.

 

[manixFan]

Also it's important to realize that the Fruity chute is much more 'powerful' in slowing down a rocket. For example, for a 25lb (11.3 kilos) rocket, the Iris chute will bring it down at a safe 19fps (5.8 meters per second), but the Topflight chute would be an unsafe 32fps (9.8 m/sec). So you can see that for the same size of chute the Fruity chute is much more effective, but at a far greater cost. The 70" Topflight chute would be great for a rocket up to about 9lbs. (4 kilos)

I use both kinds of chutes. For most rockets I can use the less expensive chutes and they work just fine. But I fly a lot of minimum diameter rockets that are tight on space so the Fruity chutes work great for those and are worth the extra expense.

Fruitychutes has a great descent rate calculator:

https://fruitychutes.com/help_for_parachutes/parachute-descent-rate-calculator.htm

It allows you to compare their chutes to other brands. There are other similar calculators available. It is really important to make sure the chute is correctly sized to how heavy your rocket is and for the space you have available. While the two chutes you are looking at are the same diameter, they are not meant for rockets of similar weight.


Tony

 

[yucel]

Also it's important to realize that the Fruity chute is much more 'powerful' in slowing down a rocket. For example, for a 25lb (11.3 kilos) rocket, the Iris chute will bring it down at a safe 19fps (5.8 meters per second), but the Topflight chute would be an unsafe 32fps (9.8 m/sec). So you can see that for the same size of chute the Fruity chute is much more effective, but at a far greater cost.

I use both kinds of chutes. For most rockets I can use the less expensive chutes and they work just fine. But I fly a lot of minimum diameter rockets that are tight on space so the Fruity chutes work great for those and are worth the extra expense.


Tony

Thenk you for your reply Tony
actually we are a team for a competition and we calculate the size of parachute with a formule and it must be 180 cm and competititon rule say you cant use under 180 cm and it must be bring down 9 m/s . so if their packing volume is same ı should use the cheap one right? in top flight recover site is no information about packing volume. our parachute areas diameter is 12.2 cm and 20 cm high so 70" top flight recovery parachute is okey for this size what is your opinion.

 

[manixFan]

Thenk you for your reply Tony
actually we are a team for a competition and we calculate the size of parachute with a formule and it must be 180 cm and competititon rule say you cant use under 180 cm and it must be bring down 9 m/s . so if their packing volume is same ı should use the cheap one right? in top flight recover site is no information about packing volume. our parachute areas diameter is 12.2 cm and 20 cm high so 70" top flight recovery parachute is okey for this size what is your opinion.

Well, since this is a competition, here is a great paper that discusses packing density:

https://fruitychutes.com/files/blog/NARCON 2013 - Rocket Recovery Technology.pdf

You will find information on parachutes and their density and packing. I can't answer if the chute will fit because it depends on how much space your recovery harness and chute protector will take. Don't forget that you much protect the chute from the ejection gases or it will get burned and melt. Generally it is wrapped in a Nomex cloth - that will take up extra room. If you are using tubular nylon for your recovery harness that takes up a lot more room than a Kevlar harness. Also add in things like quick links and the overall space required can be quite a bit more than just the chute itself.

You haven't said how heavy your rocket is - that is really the best way to determine what parachute to use. You can have several chutes that are 180cm in diameter but they can have very different descent rates. A simple flat sheet chute compared to a domed panel chute will perform very differently, as will an Iris chute. Some of that is discussed in the link above.

A simple test would be to get a large sheet of plastic, like a heavy duty garbage bag or a thin plastic drop cloth like used for painting, and cut a circle out of it that matches your estimated size. Even if you have to use several pieces that's ok. Then you can use that to get a rough estimate of how large a volume you need to pack your chute, keeping in mind the other things you'll need to get in that same space. To estimate the Nomex cloth, you can use the material from a cotton t-shirt (but only for the estimate!)

Good luck,


Tony

 

[Nytrunner]

If I recall correctly, this Turkish competition uses non-pyro deployment, so that's a bonus

 

[yucel]

Also it's important to realize that the Fruity chute is much more 'powerful' in slowing down a rocket. For example, for a 25lb (11.3 kilos) rocket, the Iris chute will bring it down at a safe 19fps (5.8 meters per second), but the Topflight chute would be an unsafe 32fps (9.8 m/sec). So you can see that for the same size of chute the Fruity chute is much more effective, but at a far greater cost. The 70" Topflight chute would be great for a rocket up to about 9lbs. (4 kilos)

I use both kinds of chutes. For most rockets I can use the less expensive chutes and they work just fine. But I fly a lot of minimum diameter rockets that are tight on space so the Fruity chutes work great for those and are worth the extra expense.

Fruitychutes has a great descent rate calculator:

https://fruitychutes.com/help_for_parachutes/parachute-descent-rate-calculator.htm

It allows you to compare their chutes to other brands. There are other similar calculators available. It is really important to make sure the chute is correctly sized to how heavy your rocket is and for the space you have available. While the two chutes you are looking at are the same diameter, they are not meant for rockets of similar weight.


Tony

thank you so much

 

[yucel]

If I recall correctly, this Turkish competition uses non-pyro deployment, so that's a bonus

exactly we are using mechanical deployment and ejection

 

[ibanerjee20]

Hi Buddy!

It's good that you have shortlisted these two parachutes for your purpose. And now you're seeking information in order to decide which one will suit your purpose. I will suggest you to test both of the designs according to your application. You do not need to make your decision based on mere theoretical explanations. Try them out on Simulations. There are some platforms where you can do that without having to dig deep into the literature. You’ll definitely make a better judgement if you see the dynamics on a computer simulation or data visuals.



Best wishes

Ishan Banerjee
Zeus Numerix