Results 1 to 28 of 28
  1. #1

    is there a max wind speed you should not launch you rocket in?

    I live in north central IL and it is always windy, I was just wondering is there a certain MPH that I should stop launching at? I know that the more wind the more chance for it to float away.... but how much would say a 17-20mph wind move a rocket?

  2. #2
    Join Date
    13th November 2009
    Location
    Katy, Near Houston (still Texas, though)
    Posts
    3,550
    According to NAR code:

    9. Flight Safety. I will not launch my rocket at targets, into clouds, near airplanes, nor on trajectories that take it directly over the heads of spectators or beyond the boundaries of the launch site, and will not put any flammable or explosive payload in my rocket. I will not launch my rockets if wind speeds exceed 20 miles per hour. I will comply with Federal Aviation Administration airspace regulations when flying, and will ensure that my rocket will not exceed any applicable altitude limit in effect at that launch site.
    The drift is a function of the wind speed, descent rate, and mass. The heavier the object, the less it will want to move horizontally. On windy days, think smaller chute, or even streamer.

    Greg

  3. #3
    Join Date
    18th January 2009
    Location
    west Ft Worth
    Posts
    2,293
    It really is as simple as that, just like Greg G just posted.

    When it's a 19-and-a-half mph day, and you want to improve your chances as much as possible, you need to use a longer launch guidance system and a more rigid, stiff launch guide. This usually means going up in size to 1/4 inch diameter launch rods (or bigger) and using a 4, 5, or 6 foot length. (Yeah, you need 1/4 inch launch lugs on your rocket too.) You can find steel round rod at a lot of local hardware stores, in the section with angle stock, bar stock, and all-thread.

    Even better, a launch rail (properly built) is a rock-solid system. These can be used even with model rockets, although most guys probably use them for mid-power motors and larger. The rail (and the rest of the launcher) needs to be well built, but you can find lots of designs for sale and more designs posted on the web that you can build yourself. With a 6 or 8 foot long guide rail, your rockets will get a much better chance to build up safe flying speed on a windy day before they leave the end of the rail. You will have to change your launch lugs for rail buttons, but that's usually no big deal.

    One other option: you might want to look into a tower launcher. You can build one with an old bucket, a sack of concrete, and three straight pieces of electrical conduit (metal pipe). You won't need a launch lug, and if you pot the conduit into the bucket with concrete (permanently) it won't be adjustable for different sized rocket diameters. But then, if you want to get fancy, there are plans available for adjustable towers.

    I'm sure these guys can pitch in with a ton of suggestions for launch hardware.
    This is the country that built the transcontinental railroads, the Hoover dam, the Panama canal, coast-to-coast interstates, and put men on the moon....but we can't build a fence.

  4. #4
    Join Date
    4th May 2010
    Location
    Pensacola, Florida
    Posts
    151
    I'm like NASA. I don't launch if it even looks like the wind speed will be 10 knots.

    And I fly "chunky" rockets.

  5. #5
    Join Date
    28th September 2009
    Location
    Seattle, WA
    Posts
    411
    Most I've done 10-15 mph and rocket came back where I wanted. With correct wind correction.
    -Andy

  6. #6
    Join Date
    26th January 2009
    Location
    Odenville, Alabama
    Posts
    430
    Quote Originally Posted by jpbell View Post
    I live in north central IL and it is always windy, I was just wondering is there a certain MPH that I should stop launching at? I know that the more wind the more chance for it to float away.... but how much would say a 17-20mph wind move a rocket?
    As you might imagine there are many factors involved as to the maximim speed you can fly safely and it pretty much comes down to the rocket you want to fly. The larger your rockey the more sensitive it will be to surface speed as it leaves the rod. Rod whip quickly becomes a factor and has been stated the safety code suggests all operations cease at 20mph. Personally, I think 20 mph is too high most of the time and for most rockets. Getting it back is a minor factor, being safe is the main concern.

    I have found short or stubby rockets do not fly well in winds over 12 mph and tend to go ballistic not far off the rod. I once saw 8-9 different Fat Boys launched in winds above 15 mph and 100% went horizontal about 50' off the ground and most hit and skimmed the ground before ejection.

    I have flown rockets like an Alpha in winds over 15 mph with no problem because they leave the pad quickly and have little side surface area for the wind to act on in a cross wind. On the other hand we never launch an Estes Saturn V size rocket when the surface winds exceed 8 mph, even if it's clustered.

    If you're at a launch and you see tables and tents being buffeted or collapsing, you might want to think twice about flying that day.

    Verna
    www.vernarockets.com

  7. #7
    Join Date
    6th June 2009
    Location
    Metro Motown, MI
    Posts
    1,658
    You're also under the limits of the 30-degree-from-vertical rule for launch rod orientation, so your options to compensate for a crosswind by launching into the wind are limited.

    So you better a) have a large open launch area and b) be ready to take a hike to track down your drifting rockets. As Greg Gleason points out, streamers are a real good idea on breezy days.

    As Jordan Rochella says, my own personal rule-of-thumb is anything over 10 mph is Scrub City. Over the years I think I have launched a couple times in 15-20 mph breezes, but it usually results in some real cross-country hiking or lost rockets.

    Certainly I wouldn't launch anything, a) I expected to go very high, or b) was any kind of 'irreplaceable' rocket I really didn't want to lose.

  8. #8
    Also bear in mind stability. Wind speed affects that too and what would be stable in low wind could be very unstable in high winds.

  9. #9
    Join Date
    16th August 2011
    Location
    Edmonton, Alberta, CANADA
    Posts
    2,913
    Quote Originally Posted by donperry View Post
    Also bear in mind stability. Wind speed affects that too and what would be stable in low wind could be very unstable in high winds.
    Oh yeah. BIG TIME!

    Me? I don't fly in winds over 25 km/hr (15.5 MPH). But I always sim my rocket builds at 25 km/hr winds and adjust the rocket so it has good stability off the launch rod at those speeds. Better safe than sorry.
    Plays with wood, cardboard, and carpenters glue at home.

    "We have done the impossible and that makes us mighty"
    -rocketeers vs. BATF

    Ego intentio parumper perficio fuga , tamen Ego peto a perficio reverto.

  10. #10
    Join Date
    18th January 2009
    Location
    Back up in the woods
    Posts
    7,644
    Quote Originally Posted by Verna View Post
    The larger your rockey the more sensitive it will be to surface speed as it leaves the rod.
    Ironically, the same holds true for the smallest rockets, powered by MicroMaxx motors. They have so little mass that many of them are easily blown around by mild wind gusts. And even if the rocket boosts straight, a breeze can really carry it far as it recovers.
    Mark S. Kulka NAR 86134 L1, ASTRE 471, Adirondack Mtns., NY
    Opinions Unfettered by Logic • Advice Unsullied by Erudition • Rocketry Without Pity
    In the forest no one can hear you order a grande caffè misto.
    Warning: I brake for invisible squirrels

  11. #11
    Join Date
    18th August 2010
    Location
    Belvidere, IL
    Posts
    70
    Quote Originally Posted by jpbell View Post
    I live in north central IL and it is always windy, I was just wondering is there a certain MPH that I should stop launching at? I know that the more wind the more chance for it to float away.... but how much would say a 17-20mph wind move a rocket?
    I live in north central Illinois too (Belvidere) and we have a windsock on a tripod that we use to gauge the wind at the launch site. A "no fly" day is when the tripod blows over in the wind.

    As it gets windier, we launch with smaller engines and have smaller parachutes and streamers for recovery. We'll also angle the launch rod into the wind, but you have to be careful not to overcompensate. Just a couple of degrees off straight up will compensate for a steady 10 mph wind.
    SPIT: Space Program in Training
    Official Site of Bob and Daniel's Model Rocket Flights

  12. #12
    Join Date
    18th January 2009
    Location
    Back up in the woods
    Posts
    7,644
    Quote Originally Posted by RadioFlyer View Post
    I live in north central Illinois too (Belvidere) and we have a windsock on a tripod that we use to gauge the wind at the launch site. A "no fly" day is when the tripod blows over in the wind.

    As it gets windier, we launch with smaller engines and have smaller parachutes and streamers for recovery. We'll also angle the launch rod into the wind, but you have to be careful not to overcompensate. Just a couple of degrees off straight up will compensate for a steady 10 mph wind.
    We flew in rather gusty conditions yesterday (never more than the MRSC max, though) as well, but we tried the counterintuitive technique of angling the launch rods slightly with the wind. One flyer had a nice vertical launch of his Estes Night Wing (notorious for weathercocking) by using this technique. My Der Fat Max on a D12 landed within arm's length of the pad when I angled the launch rod this way. I used to be skeptical of this recommendation but now I'm a believer. The wind apparently pushes the rocket into a more vertical path if you angle the rod slightly with the wind.
    Mark S. Kulka NAR 86134 L1, ASTRE 471, Adirondack Mtns., NY
    Opinions Unfettered by Logic • Advice Unsullied by Erudition • Rocketry Without Pity
    In the forest no one can hear you order a grande caffè misto.
    Warning: I brake for invisible squirrels

  13. #13

    Question about the NAR code

    Assuming there is not an anemometer at a launch, and during the course of the launch the wind speed seems to be increasing, how would you know if the wind was 18mph, or 22mph?
    SEVRA - Southeastern Virginia Rocketry Association


    Photo is Greg Gardner's K-Bomb ll
    Taken by Patrick McConnell at RED GLARE V

  14. #14
    Join Date
    19th January 2009
    Location
    Southern California
    Posts
    3,619
    Quote Originally Posted by Joe V View Post
    Assuming there is not an anemometer at a launch, and during the course of the launch the wind speed seems to be increasing, how would you know if the wind was 18mph, or 22mph?

    Good question. If you do not know you are safe and legal, then you cannot launch.

    You cannot say "I'm not sure if I'm legally complying with the maximum wind speed part of the safety code, but I'll go ahead and launch anyway."

    Windmeters are cheap. Every NAR section should have one with the plentiful safety grants available. Individuals can afford them as well.

    https://www.google.com/search?q=wind...archBox&ie=&oe=

  15. #15
    Join Date
    19th January 2009
    Location
    Washington D.C.
    Posts
    4,279
    Quote Originally Posted by Joe V View Post
    Assuming there is not an anemometer at a launch, and during the course of the launch the wind speed seems to be increasing, how would you know if the wind was 18mph, or 22mph?
    There are some very inexpensive surprisingly accurate hand held Anemometers or wind meters available through Edmund Scientific and others on-line. I've carried one of the old time Dwuer floating ball windmeters in my range box from almost launch day #1, At the time they were offered through either Estes or Centuri catalog don't recall which. I think it was under 5bucks. Today I seem to recall seeing them listed at about 12 or 15 Still a deal for our purposes. Into-the-Wind Kite stores carry a couple different electronic models ranging 65 to 150 bucks.

    Micro's really don't much care for surface breezes over 10mph, our NAR sporting code has us hold launching over 20 mph.

    These day I use a little more involved Weather Station at launches

    or There is Always an Old BSA Hold-Over the Weather Rock. always fun
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Dwyer floating ball windmeter-sm_07-20-86.jpg 
Views:	61 
Size:	86.6 KB 
ID:	78896   Click image for larger version. 

Name:	Weather Station-3d2-sm_3 pic pole & tabletop mts_03-27-88.jpg 
Views:	62 
Size:	79.0 KB 
ID:	78897   Click image for larger version. 

Name:	The Weather Rock-b_ECRM-34_04-21-07.JPG 
Views:	85 
Size:	256.5 KB 
ID:	78898   Click image for larger version. 

Name:	Weather Rock-d_3pic pg_10-83.jpg 
Views:	85 
Size:	141.7 KB 
ID:	78899  
    Keep em Flyin Micronzied
    John
    Mrcluster/Micromeister
    Nar-15731
    Co-moderator MicroMaxRockets yahoo group.
    http://groups.yahoo.com/group/MicroMaxRockets/
    Narhams Section 139 - ROMCC

  16. #16
    Join Date
    19th November 2009
    Location
    Brooklyn, NY
    Posts
    854
    Above 15 and I only fly Applewhite kits as they don't drift far. They sure do fly funny in the wind!

  17. #17
    Join Date
    10th November 2011
    Location
    Northeastern Maryland
    Posts
    779
    Just to clarify a point, relating the NAR's safety code to doing something "legally" is not accurate. The NAR safety code is a set of guiding principles established by a non-profit organization and IS NOT law.

    Launching when a bit windy? Use a higher thrust motor and lower drag recovery system such as a smaller chute or streamer.

    As for determining windspeed? I have one of these:

    -James Hamilton
    L2
    https://sites.google.com/site/disasterguysrocketry/
    I love America but I also love Canadian bacon, whiskey, and MOTORS.

  18. #18
    Join Date
    19th January 2009
    Location
    Southern California
    Posts
    3,619
    Just to clarify a point and avoid having some random forum poster advise you to do something that may very well be illegal: the NAR Model Rocket Safety Code is part of the NFPA code and the NFPA code is indeed fire code in many states.

    Do not take legal advice to go ahead and do something that is very likely illegal from forum posters who are not your attorney on retainer.

    You can search this forum for many past discussions of law and NFPA. No need to repeat the past threads.


    Quote Originally Posted by Disaster_Guy View Post
    Just to clarify a point, relating the NAR's safety code to doing something "legally" is not accurate. The NAR safety code is a set of guiding principles established by a non-profit organization and IS NOT law.

    Launching when a bit windy? Use a higher thrust motor and lower drag recovery system such as a smaller chute or streamer.

    As for determining windspeed? I have one of these:


  19. #19
    Join Date
    10th November 2011
    Location
    Northeastern Maryland
    Posts
    779
    Perhaps you misunderstand my point... I am not advising that it is particularly prudent not to follow the safety code however the fact remains that it (in itself) is not law. NFPA is not (in itself) law. Adopting a NFPA standard (such as NFPA 1 and 101 that most states have adopted in whole or part) does not imply that all NFPA standards have been adopted or enacted into law. In fact, even if a state adopts a NFPA code does not in many states translate to that same full standard being applied in all counties and/or municipalities. My point is that stating that the safety code is law is a broad generalization.

    Am I a lawyer? Nope... Am I responsible for interpreting NFPA codes and other standards as they apply to lifesafety on a daily basis as a core part of my full-time job? You bet... Am I certified as a fire inspector and plans examiner to determine what does and doesn't meet code and if it has the force of law in that given situation? Once again, you bet...
    -James Hamilton
    L2
    https://sites.google.com/site/disasterguysrocketry/
    I love America but I also love Canadian bacon, whiskey, and MOTORS.

  20. #20
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
    Posts
    1,615
    If your rocket really scoots off of the pad, you can get a way with flying up to the 20 mph limit. But slow-liftoff, long-burn rockets are a bad idea above about 10 mph. (E9 in a Blue Ninja, for example).
    It's all about A) the angle of attack when the rocket leaves the guide and B) how much pitch inertia it has.
    For a low angle of attack, the rocket speed needs to be a lot higher than the wind speed to have a low wind angle of attack. Angling the rod with the wind really does help to keep the flight more vertical, too.
    It's true that long, skinny rockets are better than squat ones when the wind picks up, because they don't pitch over into the wind as quickly. If you have a rocket that you might fly on an E9 on a good day, fly it on a C11 (or better yet, an E75) when it's windy and it will be fine.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  21. #21
    Join Date
    6th June 2009
    Location
    Metro Motown, MI
    Posts
    1,658
    Quote Originally Posted by MarkII View Post
    We flew in rather gusty conditions yesterday (never more than the MRSC max, though) as well, but we tried the counterintuitive technique of angling the launch rods slightly with the wind. One flyer had a nice vertical launch of his Estes Night Wing (notorious for weathercocking) by using this technique. My Der Fat Max on a D12 landed within arm's length of the pad when I angled the launch rod this way. I used to be skeptical of this recommendation but now I'm a believer. The wind apparently pushes the rocket into a more vertical path if you angle the rod slightly with the wind.

    If you tilt your launch rod with the wind, the rocket will indeed weathercock into a more vertical trajectory, i.e. likely to reach a higher altitude. Which will result in a longer recovery hike as it drifts downwind.

    The old-rocketeer rule of thumb is to tilt the launch rod into the wind, which ususally results in the rocket weathercocking even more significantly into the wind, possibly ending up with near-horizontal boost, with ejection taking place upwind (from your vantage point at the pad) at a relatively low altitude, and then, at least hopefully, drifting right back down into your lap.

    Of course all this beautiful theory goes out the window if you misjudge the speed or exact direction of the wind (or if it gusts or shifts). If you think the wind is coming at 5 mph from the E and then it shifts to 15 from the SE, you could be in for a hike.


  22. #22
    Join Date
    18th January 2009
    Location
    Oviedo, FL
    Posts
    3,269
    Quote Originally Posted by JStarStar View Post
    The old-rocketeer rule of thumb is to tilt the launch rod into the wind, which ususally results in the rocket weathercocking even more significantly into the wind, possibly ending up with near-horizontal boost, with ejection taking place upwind (from your vantage point at the pad) at a relatively low altitude, and then, at least hopefully, drifting right back down into your lap.
    I usually don't tilt the launch rod at all (unless other rockets have flown over people or have drifted into the wrong areas for recovery).

    My thought is that the rocket will arc into the wind during flight, then drift with the wind during recovery - cancelling out the effect of the wind. Of course, the rocket drifts under the parachute or streamer for a longer period of time, so it usually drifts farther horizontally than it flew. Tilting the rod a little into the wind would reduce the distance I have to walk to recover the rocket. But, using my technique, I don't need to predict which way or how hard the wind will be blowing at launch and it usually seems to work out well.

    -- Roger

  23. #23
    Join Date
    22nd January 2009
    Location
    Palo Alto, CA
    Posts
    1,615
    Quote Originally Posted by JStarStar View Post
    If you tilt your launch rod with the wind, the rocket will indeed weathercock into a more vertical trajectory, i.e. likely to reach a higher altitude. Which will result in a longer recovery hike as it drifts downwind.

    The old-rocketeer rule of thumb is to tilt the launch rod into the wind, which ususally results in the rocket weathercocking even more significantly into the wind, possibly ending up with near-horizontal boost, with ejection taking place upwind (from your vantage point at the pad) at a relatively low altitude, and then, at least hopefully, drifting right back down into your lap.

    That way also results in a lot of horizontal airspeed at parachute ejection, often leading to a zipper or worse. IMO, it's better to locate the launcher at the farthest upwind part of the flying field and tilt it downwind a bit. It's a longer walk, but a nicer, more vertical flight and a lot less chance of damage.
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  24. #24
    Join Date
    19th November 2009
    Location
    Brooklyn, NY
    Posts
    854
    Also guilty of aiming the launch pad into the wind, been doing it for years... and it works wonders. If you get a feel for it, you can get the rocket landing close to the pad even on a windy day.

  25. #25
    Join Date
    6th June 2009
    Location
    Metro Motown, MI
    Posts
    1,658
    I've never had any big problem with zippers when tilting the launch rod into moderate wind.

    My completely unscientific guess is that tilting into a moderate wind increases the relative airspeed of the rocket. When powered thrust ends and you go into delay, drag on the rocket is higher and thus you lose airspeed faster until the point of ejection, reducing the likelihood of a zipper. Although in all honesty probably those two factors cancel out to a large extent.

    If the wind is strong enough that even launching straight into it significantly increases your chances of a zipper, my guess is you probably shouldn't be launching anyway.

  26. #26
    Quote Originally Posted by Adrian A View Post
    .....
    It's true that long, skinny rockets are better than squat ones when the wind picks up, because they don't pitch over into the wind as quickly. If you have a rocket that you might fly on an E9 on a good day, fly it on a C11 (or better yet, an E75) when it's windy and it will be fine.
    That is the general understanding, but what makes this problematic is that there is research that says something else!
    What Barrowman Left out - http://projetosulfos.if.sc.usp.br/ar...l39-galejs.pdf
    Last edited by donperry; 17th April 2012 at 04:11 AM.

  27. #27
    Join Date
    18th January 2009
    Location
    Back up in the woods
    Posts
    7,644
    Quote Originally Posted by shreadvector View Post
    Good question. If you do not know you are safe and legal, then you cannot launch.

    You cannot say "I'm not sure if I'm legally complying with the maximum wind speed part of the safety code, but I'll go ahead and launch anyway."

    Windmeters are cheap. Every NAR section should have one with the plentiful safety grants available. Individuals can afford them as well.

    https://www.google.com/search?q=wind...archBox&ie=&oe=
    Weather Underground...

    ...but having club members who work at the Atmospheric Sciences Research Center also helps.

    We consult the meteorological data and forecast to get a general sense of the wind pattern for the day at the site. If the range is marginal (gusts of 15+ mph), we don't launch. Usually when the air is that turbulent, other associated meteorological events (existing or incoming storm systems, for example) prompt launch cancellations anyway. No need to parse out whether the current wind speed is 18 mph or 22 mph, because if it's anywhere above ~15 mph, it's always a bad day weather-wise. Our field limit is G, so we are not going to be launching anything that can punch through a moderately strong wind.
    Mark S. Kulka NAR 86134 L1, ASTRE 471, Adirondack Mtns., NY
    Opinions Unfettered by Logic • Advice Unsullied by Erudition • Rocketry Without Pity
    In the forest no one can hear you order a grande caffè misto.
    Warning: I brake for invisible squirrels

  28. #28
    Join Date
    18th January 2009
    Location
    NE Illinois
    Posts
    647
    I live in a suburb of Chicago, so you guys are west of me. But I do notice the windmill farms when I get out your way. Sure must be windy!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •