Kit chutes too small

[Azamiryou]

I've found that many of my kit LPR rockets (Estes, Apogee) land hard — hard enough to be damaged — if I use the chute that comes with the kit. I've taken to making my own chutes an inch or two bigger, or sometimes just grabbing a chute from a bigger kit, and that solves the problem (at the cost of increased drift, of course).

Why are the provided chutes too small? Is it the thinner air here a mile above sea level? (Would seem odd, since both Estes and Apogee are in Colorado!) Does anyone else have this issue?

 

[CalebJ]

I've found that many of my kit LPR rockets (Estes, Apogee) land hard — hard enough to be damaged — if I use the chute that comes with the kit. I've taken to making my own chutes an inch or two bigger, or sometimes just grabbing a chute from a bigger kit, and that solves the problem (at the cost of increased drift, of course).

Why are the provided chutes too small? Is it the thinner air here a mile above sea level? (Would seem odd, since both Estes and Apogee are in Colorado!) Does anyone else have this issue?

What surface are you flying from?

 

[sr205347d]

Is it the thinner air here a mile above sea level?

Yes. I learned how to skydive in Colorado. I was amazed how cushy the thick air is at sea level.

 

[Azamiryou]

What surface are you flying from?

Most of my landings are on mown grass (city parks or schoolyards).

Well, not counting the tree landings...

 

[MClark]

Small chutes are cheaper.
Their business is making money not rockets

 

[Daddyisabar]

Go up to Hartsel with Tripoli Colorado at 8800 feet elevation and it gets even worse! Everywhere the rockets are flying higher and coming down faster. Same when launching at the SLV gravel pit in Alamosa. Where is the thick, humid air of the East Coast? Where is the soft green green grass of home to land on? Where are the rocket eating trees? Where are the bugs and skeeters? Where are the cloudy skies?

Mr.Greeley told this young man to GO WEST. Now I am a Space Cowboy. YIKES! Take me home, country road. But then the big critters show up at the launch and they only like the BIG MOTORS!

 

[neil_w]

That is not my experience at sea level. Yeah, the thinner air there is going to make a big difference. Also the particular rocket design (eg fins that extend behind the rocket).

 

[ljwilley]

Mr.Greeley told this young man to GO WEST. Now I am a Space Cowboy. YIKES! Take me home, country road. But then the big critters show up at the launch and they only like the BIG MOTORS!

Wow! Did you take that pic?

 

[Buckeye]

I've found that many of my kit LPR rockets (Estes, Apogee) land hard — hard enough to be damaged — if I use the chute that comes with the kit. I've taken to making my own chutes an inch or two bigger, or sometimes just grabbing a chute from a bigger kit, and that solves the problem (at the cost of increased drift, of course).

Why are the provided chutes too small? Is it the thinner air here a mile above sea level? (Would seem odd, since both Estes and Apogee are in Colorado!) Does anyone else have this issue?

The designer likely uses the dry mass of the rocket parts (not including glue, paint, hardware, payloads, and other stuff that you may add) when computing the chute size. Also, sea level air density is pretty standard in the calcs.

 

[jadebox]

Where is the thick, humid air of the East Coast?

It's counter-intuitive but humid air is actually less dense than dry air.

 

[Daddyisabar]

Wow! Did you take that pic?

No, it was George Barnes IV. I missed that day the critters came by to inquire about a Junior Level one. More of George's photos for your entertainment.



The Great White Bison came by to RSO the EX O motor launch. Looked over the propellant mix formula and commented "GOOD MEDICINE. "

Been to rocket launches from one side of the State to the other. Seen a lot of strange things. But nothing that would tell me a descent calculator on my fancy phone will tell me the right chute size to prevent landing damage up here in South Park.

 

[Daddyisabar]

It's counter-intuitive but humid air is actually less dense than dry air.

And that super cold air can be a bugger too! Why do I hear the motor sound so much better? What happened to my awesome performance that I got just a few weeks back in autumn? Dang it! Can't figure it out! Rocket science is soooo hard!

 

[Daddyisabar]

The designer likely uses the dry mass of the rocket parts (not including glue, paint, hardware, payloads, and other stuff that you may add) when computing the chute size. Also, sea level air density is pretty standard in the calcs.

Go to SCORE in Pueblo and ask the designers themselves! They will tell you stories of things flying great at Penrose and then just awful at Sea Level. So much that it impeads on the "Idiot factor " they have to calculate into each design. YIKES! Never knew so much effort required to design at kit! And that is before the hardest part: Getting the naming rights from the legal department! Now that is a real PAIN!

 

[Daddyisabar]

The Top Men designers also say they oversize the chutes for LPR kits for Sea Level. The kit must have adequate recovery room. But flying on a Rocky Mountian High...you are on yer own partner!

 

[jadebox]

And that super cold air can be a bugger too! Why do I hear the motor sound so much better? What happened to my awesome performance that I got just a few weeks back in autumn? Dang it! Can't figure it out! Rocket science is soooo hard!

For me, having lived all my life in Florida, when I visited Denver and worked in a building on the side of a mountain it was:

Hey! Why can't I breathe!

 

[Hobie1dog]

a seasoned veteran told me," You know they deign LPR chutes for asphalt parking lots, so our chutes could be smaller" As we watched a rocket hang in the air and heading for the trees.

 

[Daddyisabar]

For me, having lived all my life in Florida, when I visited Denver and worked in a building on the side of a mountain it was:

Hey! Why can't I breathe!

The Top Men are back in those windowless buildings on the side of the mountain in Waterton Canyon designing the real big rockets to take up "THE PACKAGES" For the NRO. No chutes needed!

 

[jadebox]

The Top Men are back in those windowless buildings on the side of the mountain in Waterton Canyon designing the real big rockets to take up "THE PACKAGES" For the NRO. No chutes needed!

The rooms I worked in had windows. Seeing mountains out the window makes it really hard for a guy from Florida to pay attention during meetings.

And I really did get winded walking up stairs.

 

[Daddyisabar]

a seasoned veteran told me," You know they deign LPR chutes for asphalt parking lots, so our chutes could be smaller" As we watched a rocket hang in the air and heading for the trees.

Yeah, the designers live close to Penrose, so they forget about rocket eating trees. Just give the gentlemen East Coasters a spill hole to cut out. That should do!

 

[Azamiryou]

a seasoned veteran told me," You know they deign LPR chutes for asphalt parking lots, so our chutes could be smaller" As we watched a rocket hang in the air and heading for the trees.

Sooo... they design for the middle elevations, leaving sea level flights to drift over the horizon, and Rocky Mountain flights to smash themselves to bits on the ground.

Seems reasonable.

Glad it's not just me! I'll keep swapping in bigger chutes.

 

[Daddyisabar]

The rooms I worked in had windows. Seeing mountains out the window makes it really hard for a guy from Florida to pay attention during meetings.

And I really did get winded walking up stairs.

I know what you mean! I worked in a building where the conference room had a mountain view then back to my office that had a view of the airport and planes taking off/landing. Knowing Apogee Components was only a stones throw away to buy lots of stuff, I had to buckle down and make lots of money to cover the high cost of living and support my model rocketry habit.

 

[Daddyisabar]

Sooo... they design for the middle elevations, leaving sea level flights to drift over the horizon, and Rocky Mountain flights to smash themselves to bits on the ground.

Seems reasonable.

Glad it's not just me! I'll keep swapping in bigger chutes.

Just watch out for those windy days. Slow descents close to the pad are always a crowd pleaser. Get the Apogee SHX kit with the huge stock chute for slow descent. A Shrox design, nice and light, no wind, big chute, on a D12 3 in the school yard. Awesome!

 

[Daddyisabar]

Seek out the Jedi parachute duration masters. They will show you the way. Huge custom designed chutes made of the finest, exotic materials. Full length folding tables, superb packing techniques, mysterious powders and swivels.

 

[cwbullet]

I have not found the chutes to be too small. I am near sea level so maybe that actually makes a difference.

 

[jadebox]

I have not found the chutes to be too small. I am near sea level so maybe that actually makes a difference

Same here. Many at our local club launches reef up the shroud lines or cut a spill hole in the 'chute to increase the descent rate a bit to keep the rockets from drifting into the trees near our field.

 

[cwbullet]

Same here. Many at our local club launches reef up the shroud lines or cut a spill hole in the 'chute to increase the descent rate a bit to keep the rockets from drifting into the trees near our field.

Trees bad. Reef good. Same here.

 

[lakeroadster]

I've found that many of my kit LPR rockets (Estes, Apogee) land hard — hard enough to be damaged

Brittle rockets.... break easily. Upgrade to papered balsa, basswood, or basswood ply.
<-----

 

[Astrobuf]

I live in mn at about 900ft elevation. If anything zi find the standard chutes to be bigger than I like. I usually cut out the estes logo hole in the chute to increase chances of recovering the rocket. If you are at a higher altitude (say Denver) your experience might make sense. Your problem could be fabrication though. Are your fin fillets well done? Are your chute lines cleanly aligned, crossed or tangled? It's possible your chutes are not opening fully. What kind of damage are you experiencing?

Astrobuf

 

[smstachwick]

It’s not just the chutes, it’s also your choice of materials and your build technique. Are you using CA? Wood glue? White glue? Epoxy of some kind?

That question is mostly illustrative but I’m always up to watch a good glue thread!

With balsa surface-mount fins, are you using a double glue joint to fill in the porous balsa surface and tack the fin better? Are you using a jig to (gently, please) clamp things together? Are you making any fillets to strengthen the attachment points? Have you considered upgrading to through-the-wall mounting?

What kind of payloads are you flying, if any? How heavy are they?

Lastly, are you looking at the quality of your tubes? Some types can reliably compress with rough handling or a solid bonk delivered to the end on landing.

 

[Azamiryou]

What kind of damage are you experiencing?

Everything from popped off fins to broken fins and bent body tubes.

It’s not just the chutes, it’s also your choice of materials and your build technique. ...

Materials are almost always whatever came in the kit, and I usually use the adhesives recommended in the kit instructions unless I know better (like staying away from CA in any use that will be subject to shocks). I double glue and fillet my fins, usually with epoxy putty.

One modification I almost always make is to put a spill hole in the chute. It's small, though, just the size printed on the chute, so it doesn't speed up the descent much — but it does reduce any impact from wildly swinging under an unstable chute.

I've had fins come off both through the wall and surface mounted. I've had thick balsa fins that cracked or broke. (I'm not counting the inevitable dings, dents wnd chips here, I mean legitimate big cracks or chunks broken off.)

It seems when I strengthen the build, the damage moves from simple repairs (popped fin) to more complex repairs (broken fin, damaged tubes). But when I make the chute a little bit bigger, the problem goes away.

In short, I believe that my construction techniques are superior to what Estes should be expecting from the average kid building one of their kits with no guidance other than the instructions. And even that kid would be reasonable to expect their rocket to survive landing. (Which they probably can, if they live below 5000' elevation. And compared to lower elevations, hardly anyone lives up here.)

For what it's worth, I didn't have this problem flying from 4000’ as a kid in the 1970’s. I'm pretty sure my building techniques now are better, not worse! Which is why I thought it must be that the chutes are too small for the thin air, but found that surprising since the kit companies themselves are at high elevations. It makes sense though for them to design for the vast number of people at lower elevations rather than a handful of people who live in the mountains.