Concrete Landing Damage Mitigation?

Our LPR/MPR launch site is a concrete airstrip and landing on concrete is really, really bad. It's no wonder I see lots of bare, unpainted rockets flying as they'll generally end up getting trashed on the landings; there's no reason to spend lots of time of finishing the models.

On a recent launch, my kid's Alpha III plastic fin got smashed & curled badly (straightened in the pic). My tube-fin rocket had a standoff that was mashed & torn away from the tube. The tops of the body tube below the nose cones tend to get shredded too as they are dragged along the cement after landing.

Are there any general tips for protecting and/or minimizing damage on LPR/MPR models landing on concrete?

• bigger parachute (more drift, & we have to land within a target radius)
• dual-deploy (not there yet)
• overbuilding
  • CA hardening of tubes
  • laminating fins (paper, fiberglass, etc.)
  • wrapping packing tape over top of tube, below the nose cone
  • (other)
• bumpers/standoffs/shock absorbers
• flying on grass at the HPR site (not yet...)
• shelve the rocket (not a preferred option)

Keep in mind these are mostly LPR. Any general ideas that are cheap to implement on any rocket without being cumbersome and/or ugly? I'm leaning towards taping on coffee stirrers.

Any comments and/or suggestions would be greatly appreciated. Thanks!

Moffett is a rather unforgiving place to launch rockets.

Snow Ranch really is worth the drive.

Yikes!

I went through some similar issues flying out on a hard-packed dry lake.

First I tried larger parachutes. That ended in very long walks to retrieve them and it also made the on-ground dragging damage more of a problem!

I then tried overbuilding with heavier tubes and plywood fins. Then I needed bigger chutes due to the heavier weight which would in turn make the ground drag more of an issue!

I settled on standard light weight LPR kit materials and lightly fiber glassed the tubes and balsa fins. Using single wraps of 1/2 oz. cloth on tubes and 1 layer on each side of the fins. This adds very little weight and mitigates the hard surface landings and grinding damage of a harsh environment.

Most local hobby shops that sell "wooden" r/c planes and/or boats should carry light weight fiber glass cloth and finishing epoxy.

Good luck!

Jerome

Choose models with fins that do not extend past the aft MMT.

Large chutes help a bit on calm winter days but summer weather pattern means more breeze and smaller chutes.

All of us have the Moffett Fleet, and the Good Fleet.

R/C gliders. I'm telling you, that's the solution.

Ari.

grapetang said:

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Damage? I don't see no stinkin' damage! lol Looks practically new to me. Fly there awhile and we'll compare damage. Moffett is tough on rockets. I have seen some damage. Tough on kids too. That concrete is really rough. I've seen running kids step in a tie down hole and hit the concrete hard. Not pretty results.

Moffett is definitely hard on rockets. I parawadded a 4" rocket there at the last launch and the 1/4" plywood on one of the fins completely shredded (the fin is barely attached). Using heavier materials and oversizing chutes is usually okay as long as you watch the wind.

One thing to possibly consider is painting tips of fins with Plasti-dip or another kind of coating. I'm trying this on a few new builds.

Gliders really do fix the landing damage problem, like iter mentioned, but require R/C flying experience.

Eventually you will probably find you have "Moffett rockets" and avoid flying some at Moffett because of the toll concrete takes on rockets.

o1d_dude said:

Snow Ranch really is worth the drive.

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I'll get there someday!

JeromeK99 said:

I settled on standard light weight LPR kit materials and lightly fiber glassed the tubes and balsa fins. Using single wraps of 1/2 oz. cloth on tubes and 1 layer on each side of the fins. This adds very little weight and mitigates the hard surface landings and grinding damage of a harsh environment.

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Thanks for sharing that and for the helpful tips. Fiberglass is definitely on the roadmap!

cls said:

Choose models with fins that do not extend past the aft MMT.
Large chutes help a bit on calm winter days but summer weather pattern means more breeze and smaller chutes.
All of us have the Moffett Fleet, and the Good Fleet.

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Good points. My upcoming build won't have swept fins, and I'll likely reinforce the bottom end of the tube with a short coupler or tube segment if possible, plus a sacrificial standoff. I like that Moffett Fleet vs Good Fleet separation, though everything will probably end up in the Moffett Fleet (or shelved )

iter said:

R/C gliders. I'm telling you, that's the solution.

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Great solution! Maybe BG/RG for me but I could never get anything other than a standard pop-pod BG to fly properly.

4kids49 said:

Damage? I don't see no stinkin' damage! lol Looks practically new to me. Fly there awhile and we'll compare damage. Moffett is tough on rockets. I have seen some damage. Tough on kids too. That concrete is really rough. I've seen running kids step in a tie down hole and hit the concrete hard. Not pretty results.

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Yeah, you're right but that yellow & black tube-fin rocket is 30+ yrs old and has survived countless launches from my youth. I'd just like to see it survive a little longer before retiring/expiring. Also been warning my kid to watch out for those tie downs. Ouch indeed!

SCrocketfan said:

Moffett is definitely hard on rockets. I parawadded a 4" rocket there at the last launch and the 1/4" plywood on one of the fins completely shredded (the fin is barely attached). Using heavier materials and oversizing chutes is usually okay as long as you watch the wind.

One thing to possibly consider is painting tips of fins with Plasti-dip or another kind of coating. I'm trying this on a few new builds.

Gliders really do fix the landing damage problem, like iter mentioned, but require R/C flying experience.

Eventually you will probably find you have "Moffett rockets" and avoid flying some at Moffett because of the toll concrete takes on rockets.

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Thanks for the tips and sorry to hear about your rocket. Plasti-dip bumpers is an interesting idea. For my rockets, I suspect that all them will end up in the Moffett fleet!

Thanks for the suggestions, everyone!

Where I fly is at an airport, so it seems that a third of the time the rockets find the runway or the taxiway to land on. So I have to build accordingly.

On some rockets where I have fins that extend beyond the base of the airframe, I take thin piano wire and bend it into a long "U" shape and place it on the fin tips as a bumper of sorts. It works ok, if it lands square.

On scratch builts, I fiberglass the fins and the airframe. Otherwise, after a hard landing or two they would have to be retired.

But on these launch sites, you have to understand that they will be brutal and merciless on rockets and that's just the nature of the beast.

Greg

grapetang said:

Yeah, you're right but that yellow & black tube-fin rocket is 30+ yrs old and has survived countless launches from my youth. I'd just like to see it survive a little longer before retiring/expiring. Also been warning my kid to watch out for those tie downs. Ouch indeed!

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I was just kidding. Moffett is really hard on rockets if everything goes well. It can destroy rockets if there is any kind of ejection malfunction. I don't fly any of my hpr rockets there. We know going in with the kids rockets that they will get torn up, but don't have many options for us. Probably whatever I write down, someone will come back and say that they have had one of those rockets damaged at Moffett. We have had a lot of luck with Estes paper tube rockets that have wooden fins like the Mega Mosquito, Executioner, Der Red Max (regular size, have not built Mega yet), Big Daddy, can't remember others. We've had a ton of flights on Estes Blue Ninja, which is cheap, easy to build with no paint, and flies on decent size motors for kids. We've also had a lot of flights with an Estes Maxi Alpha III which has plastic fins. I have had a ton of flights on my Aerotech Sumo and G-Force, although both have numerous battle scars from Moffett. They still fly with G motors. They are not built for hpr. Again, I personally would not build a rocket for hpr and fly it at Moffett. There are people that do. Good luck with your flying. Tough place, but still a lot of fun. Not sure how long launches will continue there since Google leased the hangar there. Has anybody heard anything regarding this?

GregGleason said:

On some rockets where I have fins that extend beyond the base of the airframe, I take thin piano wire and bend it into a long "U" shape and place it on the fin tips as a bumper of sorts. It works ok, if it lands square.

On scratch builts, I fiberglass the fins and the airframe. Otherwise, after a hard landing or two they would have to be retired.

But on these launch sites, you have to understand that they will be brutal and merciless on rockets and that's just the nature of the beast.

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Thanks. I like the piano wire idea and will try not to go overboard on the fin tips & tube ends (guard rails or Centuri flying saucer-styled landing gear). Fiberglass sounds like a good option as Jerome had suggested earlier too.

4kids49 said:

I was just kidding. Moffett is really hard on rockets if everything goes well. It can destroy rockets if there is any kind of ejection malfunction. I don't fly any of my hpr rockets there. We know going in with the kids rockets that they will get torn up, but don't have many options for us. [...]
Good luck with your flying. Tough place, but still a lot of fun. Not sure how long launches will continue there since Google leased the hangar there. Has anybody heard anything regarding this?

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Oh, oh, OK. I'll stop whining. 'Tis but a scratch! Thanks for all the suggestions, hopefully I'll be able to get my kid interested. I do enjoy flying but miss going to the park or playground on a whim and launching over grass. In the end, I'll build to fly and will build the static models for display. No PMCs in the foreseeable future.

Re: Google hangar: no idea but ditch the barges and go for flying dirigibles? A blimp would be awesome! If Google is trying to extend STEM programs, we should still be able to fly.

Thanks for all the comments!

grapetang said:

Re: Google hangar: no idea but ditch the barges and go for flying dirigibles? A blimp would be awesome! If Google is trying to extend STEM programs, we should still be able to fly.

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There used to be a helium blimp in another hanger by the launch. It gave expensive rides around the bay area. It also did a lot of touch and goes during launches which added to the whole launch experience (that and working fighter jets, and other aircraft that took off and landed at the area). Helium got to be too expensive and the company went out of business, within the last 1 - 2 years. It was fun to watch.

4kids49 said:

There used to be a helium blimp in another hanger by the launch. It gave expensive rides around the bay area. It also did a lot of touch and goes during launches which added to the whole launch experience (that and working fighter jets, and other aircraft that took off and landed at the area). Helium got to be too expensive and the company went out of business, within the last 1 - 2 years. It was fun to watch.

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That would've been neat to see! Hopefully we'll have more sights from time to time like that small-scale shuttle which I also missed. Maybe Google will experiment with drone delivery, robots, or their self-navigating vehicles there.

My home launch field is NALF Fentress, an active training air strip for NAVY pilots. Though the field is massive and there is only one runway and one long taxiway beside it with associated driveways for ground support like fire trucks, etc, we seem to hit the concrete about 20% of the time. The percentage of concrete to grass can't be more 1:20, but we manage 4:20 landings on the hard stuff.

That's had me consider some ways to mitigate damage on landing. Sure, we try various launch angles, etc and consider the chute size and the drag across the asphalt that may occur on windier days, but one of the ideas that I've considered is a rubber type bumper on the bottom of the rocket body and/or fins. I haven't yet put this into practice as I always think I can outsmart the rocket-eating runway, but I was wondering if anyone has any thoughts on how this might work.

I was thinking cutting down things like the little clear bumpers that you can buy for cabinet doors from Lowe's or Home Depot. They have adhesive on them and can fairly easily be removed from the bottom of a fin edge/tip after flight. This doesn't really solve the upper body tube and nosecone damage damage that occurs, but I could put one right on the tip of the nosecone...

Thoughts?

Sounds like an interesting solution. It'll work for the fins, and if we put enough around the top of the tube, it'll probably work though it might look a little funny & increase drag. Please post if you try it!

I had an idea to put a roll cage or crow's nest near the top of the tube, but that might look worse.

Good input. Thanks!

Check out Sugru. It is a new moldable silicone rubber that comes in a variety of colors.

Thanks for the suggestion! SCrocketfan suggested Plasti-dip and similar as well, though I may look for cheaper alternatives. Thanks!

I retrofitted bumpers made of toothpicks & tried over the weekend. It adds drag but definitely helped to protect the top of the body tube, though the Alpha III tube still got banged up somehow. Some of the bumpers got ripped off the tube fin and the sacrificial standoff snapped off again but it did its job.

Still working on ideas to protect swept fins on landing...

Edit: Note that there are two bumpers around the launch rod point so as not to interfere with the rod.

I'd give Ari's solution some thought...


If disinclined toward RC glider, maybe give consideration to landing gear?


Later!

--Coop

...Nasa did that bubble wrap bouncy thing with the Mars rover... rear-deploy bubble wrap?! HA! I've no idea how you'd implement that, but it would be awesome.


Later!

--Coop

Hi Coop! Thanks for the comments - I'll get to BG's eventually; not sure about the RC part though. Landing gear & the rear deploy bubble wrap sound like interesting ideas. I'll see what I can come up with. Thanks!

No, no, no, NO. These suggestions are too clever, simple, and cheap. Let me take a Dept. of Defense perspective on this:

Use this:

https://www.ebay.com/itm/New-Ultras...sducer-Sensor-For-Arduino-Robot-/171072011934


Plus this:

https://www.ebay.com/itm/IRF520-MOS-FET-Driver-Module-for-Arduino-/171906892871



With this:

https://www.ebay.com/itm/Adafruit-T...Attiny85-Board-uses-Arduino-IDE-/171639963002



A 7.4V lipo battery and three of these:

https://www.estesrockets.com/rockets/engines/plugged-engines/001505-a10-pt-engines



To do this:

[video=youtube;4uGfOppQD_g]https://www.youtube.com/watch?v=4uGfOppQD_g[/video]

Ha ha! I like your thinking! Ultrasonic is probably better than IR, and I was going to use a plain Atmel microcontroller rather than a fancy, prepackaged Arduino to deploy something (landing gear, ballute, etc). Probably not retro thrusters though. Pretty amazing that they were lobbing tanks out of those carriers!!!

Another thought once the rocket lands: release all but one set of chute lines so the parachute deflates to prevent the rocket from being dragged across the surface.

Thanks for the cool suggestion!

grapetang said:

Ha ha! I like your thinking! Ultrasonic is probably better than IR, and I was going to use a plain Atmel microcontroller rather than a fancy, prepackaged Arduino to deploy something (landing gear, ballute, etc). Probably not retro thrusters though. Pretty amazing that they were lobbing tanks out of those carriers!!!

Another thought once the rocket lands: release all but one set of chute lines so the parachute deflates to prevent the rocket from being dragged across the surface.

Thanks for the cool suggestion!

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The Trinket only costs $7, weighs virtually nothing, and uses the Arduino IDE and most of its libraries. Why reinvent the wheel unless you just want to do so just for the heck of it? However, this was intended as a joke, I have no idea whether NAR or anyone else would have safety issues with it, a large area of concrete or totally non-flammable surface would be the only place to use this, and consider what would happen to a parked car's paint job if it decided to land on one or what would happen if it decided to land on someone's prep table or field motor box.

How about thin strips of styrofoam or foam rubber tubing lining the bottom edges of the rocket? Shouldn't add too much weight and will bring the CP back so that should counter the weight as long as you don't go with heavy stuff. May add more drag, so altitude will be lower. Should be cheap to test out and easily undone as well. Maybe start with the self-adhesive insulating foam for doors; however keep in mind to keep away from exhaust blast (that would be bad).

To protect the fins that extend below the booster (like your son's Alpha) you can try self-adhesive foam sheets (available at major craft stores) and cut squares, then stick on each side of each fin tip (extending down and maybe out a bit). You can even get the foam sheets in matching colors.

EDIT: YO! My 1000th post! :w:

Since Earth will soon be entirely paved with concrete I will immediately begin work on a solution which I can market at an outrageous price. :wink:

Winston said:

The Trinket only costs $7, weighs virtually nothing, and uses the Arduino IDE and most of its libraries. Why reinvent the wheel unless you just want to do so just for the heck of it? However, this was intended as a joke, I have no idea whether NAR or anyone else would have safety issues with it, a large area of concrete or totally non-flammable surface would be the only place to use this, and consider what would happen to a parked car's paint job if it decided to land on one or what would happen if it decided to land on someone's prep table or field motor box.

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Well, I have done some Atmel uC development from scratch so it's not so bad though I haven't looked at the Arduino IDE nor the libs. Joke or not, it's a pretty neat idea!

KenECoyote said:

How about thin strips of styrofoam or foam rubber tubing lining the bottom edges of the rocket? Shouldn't add too much weight and will bring the CP back so that should counter the weight as long as you don't go with heavy stuff. May add more drag, so altitude will be lower. Should be cheap to test out and easily undone as well. Maybe start with the self-adhesive insulating foam for doors; however keep in mind to keep away from exhaust blast (that would be bad).

To protect the fins that extend below the booster (like your son's Alpha) you can try self-adhesive foam sheets (available at major craft stores) and cut squares, then stick on each side of each fin tip (extending down and maybe out a bit). You can even get the foam sheets in matching colors.

EDIT: YO! My 1000th post! :w:

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Good suggestion. I think we'll try that! Thanks & congrats on 1000+ posts!

tmacklin said:

Since Earth will soon be entirely paved with concrete I will immediately begin work on a solution which I can market at an outrageous price. :wink:

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I'm game!

Thanks, guys!

We used to fly at the Lloyd Noble parking lot (aka "The Rock"). It's a nice wide-open space, except that it's paved in concrete. I re-(re-re-re)built a Fat Boy to be able to take repeated landings there (a few were especially hard due to chute problems). What I came up with was a design list of features: no fins or engine hooks below bottom of body tube, re-enforce aft edge of body tube, make the fins tough, don't fly it if you fall in love with it...

Here are some pics (remember, this *was* a Fat Boy at one point)

The aft edge was laminated (rather poorly, this was my first time) using fiberglass. The 24mm mount is set well inside the body tube, the engine hook is inside the aft end. Somewhere in one of the rebuilds, I added plywood fins and a good ejection baffle (the baffle *really* makes flying the rocket nice). That lump of gray stuff in the upper right of the middle picture is the end of a piece of 1/4 kevlar used for the recovery harness.