Demo Jump Flag Specifications?

[JohnRich 4]

I've got a corporate demo jump coming up in June, in which they want me to jump-in with a company flag. They offer to make the flag themselves in their shop, if I'll just provide them with the specifications as to how it is to be made.

So, does anyone have any specs already made up that they are willing to share with me?

I'm thinking some kind of engineering blueprint type drawing would be ideal.

Specs I can think of:
- Fabric: lightweight nylon that will flap in a 15-mph breeze.
- Reinforcing tape on leading edge.
- Type of thread, stitching?
- Grommet set in top and bottom of leading edge. Size/type?
- Top lanyard (length?) with quick release shackle.
- Weight bag on the bottom grommet. Filled with lead shot?
- What is the ratio of weight to surface area to load it with?
- Is there a ratio of length to height that is ideal?

I'm a bit uncomfortable with a non-skydiver constructing this. But I'm going to try and get ahold of it a couple of weeks in advance so that any necessary modifications can be made for safety, before the jump.

I'm working with a rigger for a container to put the flag in, freefall safe and ready. To be filled with foam as necessary to fill it out.

The specs have to be exact enough so that someone completely unfamiliar with skydiving and parachute rigging can make it.

Any info or recommendations you can provide would be greatly appreciated.

Yes, I've done demo jumps and flag jumps before...

[PhreeZone 15]

I've seen a design that is far better then the shot bag and that to have the leading edge made out of tublar nylon and have the lead shot in there. That way when the flag is stood up the edge is stiffened and can be flown with less weight. The tube was sewn into sections and only part of the lead was in each section so it would fold up easly still. Big thing to consider is to make sure the stitching is strong or you'll leak shot out everywhere.

Yesterday is history
And tomorrow is a mystery

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[ZigZagMarquis 8]

John,

Contact MJOSparky. He'd be the guy I'd go to if I wanted to jump a flag and wanted to get schooled up on all the stuff you ask.

[JohnRich 4]

Quote

I've seen a design that is far better then the shot bag and that to have the leading edge made out of tublar nylon and have the lead shot in there. That way when the flag is stood up the edge is stiffened and can be flown with less weight. The tube was sewn into sections and only part of the lead was in each section so it would fold up easly still.

Yep, that's a great idea, and if I was to build one myself for repeat useage, I'd do it that way.

I've done something similar with some small flags I have, by simply attaching linked chain down along the leading edge. It's flexible for folding, and distributes the weight along the entire edge, with nothing dangling down below the flag.

But this will be a one time flag, as it is a "100th anniversay" message. And I want to keep it simple for the company that is going to construct it.

[airtwardo 6]

Quote

I've seen a design that is far better then the shot bag and that to have the leading edge made out of tublar nylon and have the lead shot in there. That way when the flag is stood up the edge is stiffened and can be flown with less weight. The tube was sewn into sections and only part of the lead was in each section so it would fold up easly still. Big thing to consider is to make sure the stitching is strong or you'll leak shot out everywhere.

Hummmm.....wonder where ya got THAT idea?!

~ If you choke a Smurf, what color does it turn? ~

[airtwardo 6]

Specs I can think of:

- Fabric: lightweight nylon that will flap in a 15-mph breeze.
Strength and cost are the only considerations...how big ya wanna go?


- Reinforcing tape on leading edge.
Most of the variables you're addressing change with the flag's size John, As a rule of thumb though if it's going to be of any significant size / weight, then I wouldn't recommend using reinforcement 'tape' to the leading edge.

Instead, I would go with a light webbing, all one piece from the cut away ring to the weight attachment, you then attach the flag to that 'structurally sound' lanyard.

Using the flag itself at a load bearing part is asking for trouble.

- Type of thread, stitching?
If it's constructed as above...again size is a determining factor, but for a one time use banner attached to a solid lanyard, very lightweight materials and stitching can be used....a savings in time and materials, I've even hot glued them for a single presentation.


- Grommet set in top and bottom of leading edge. Size/type?
Again, I wouldn't recommend using grommets, a single lanyard is best and safest.


- Top lanyard (length?) with quick release shackle.
Depends on the flag size and the speed of the canopy, if you're using your classic...a short lanyard combined with minimum weight will fly it straightest.

- Weight bag on the bottom grommet. Filled with lead shot?
As Phree mentioned, the tubular nylon system is the best thing going, we've been doing it that way for 25 years, the flags fly incredibly straight, pack up well, with the weight spread like that you need less, banner won't don't 'swing' during turns, safer for the ground crew, and we've never dropped a BB.


- What is the ratio of weight to surface area to load it with?
Depends on the flag size, canopy speed and lanyard length.

There are also some 'aerodynamic' tricks that you can do to less the weight requirements.



- Is there a ratio of length to height that is ideal?
1:1.5

~ If you choke a Smurf, what color does it turn? ~

[tkhayes 126]

depends on the size of the flag. a 4'x8' flap with 10lb shot bag under the leading edge will fly nicely and can all be stuffed in your jumpsuit for the jumps,

hang it with a caribiner (sp?) from either your lift web or chest strap.

Also consider what canopy you are flying. If you want to present the flag nicely, you need a LARGE parachute. faster airspeed just makes the flag streamer, even with more weight under it. 220-260 sq ft at least is nice. - do a test jump or two

Larger flags, 10'x20 require an external container, usually something like Mark Schlatter designs, and they deploy down between your legs from the front and the weight bag can be 20-40lbs. a Y strap connects the flag to your laterals, and has a cutaway system, be very aware of the length of stuff below you and what you are flying over when on final. Snagging a power line at 70' will be horrible, no time to do anything about it.

Again LARGE parachutes to make it fly nice.

[airtwardo 6]

Quote

hang it with a carabiner (sp?) from either your lift web or chest strap.

Just a word of caution T.K.~

ALWAYS be very careful when hanging anything from your MLW's...if it has any weight there is a concern that on opening shock you possibly are putting forces against the stitching that was never designed for a load of that kind.

That goes DOUBLE for the chest strap, it's designed for sideways stress not downward.

A very well known and highly experienced demo jumper was absolutely shocked when I mentioned that to him and we went over his rig carefully, there was loosened stitches at the top of two Box X patterns, and several discoloration marks on the chest strap where the webbing had been surface abraded by the hardware from the angel of stress.

Even a 20 pound flag gets pretty heavy during the G's of opening.

Also, if carrying a folded flag in your jumpsuit...never have it 'preconnected', I saw one snake out on a guy once, a 'flag in tow' is just as bad as a pilot-chute in tow!

~ If you choke a Smurf, what color does it turn? ~

[tkhayes 126]

I was not talking about during deployment, the flag gear needs to be in a container on the front of you, attached appropriately to your harness, or stuffed in your jumpsuit.

Either way, there should be no load on your harness from opening shock, sure

TK

[airtwardo 6]

Quote

needs to be in a container on the front of you, attached appropriately to your harness

I know, that's exactly what I'm talking about, and to be clear I meant parachute deployment not flag...

It's the 'attaching appropriately' that's the gray area.

A lot of demo jumpers use carabiners or detachable D rings on the MLW.

The flag in a container, is weight not factored in during the design phase of a sport harness.

That is what was tearing the stitching in the case I mentioned above, a 20X40 flag of about 30 pounds, on a front mounted belly wart type container attached to the MLW with detachable D rings.

A lot of demo jumpers with mid to heavy flags & banners, have switched to a tandem harness utilizing the upper attachment rings, just for that reason.

Others use a 'climbing' type harness with the 'rescue' chest mounted D rings to attach the heavier flags, and I've seen several systems lately that have the flag in a tubular type container running down the jumpers left side from mid rib cage to boot top.

Our team had a couple sport rigs made up with tandem rings up high, and even incorporating a drogue for when the performance requires a terminal speed jump...we've since gone to a unique system 'designed' for that type of shock load without compromising the harness's structural integrity.

I'm not saying attaching a banner to a sport rig is certain death, just that the jumper needs to be aware of what can and has happened...and hopefully spark some thought.

~ If you choke a Smurf, what color does it turn? ~

[GrabGrass 0]

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Either way, there should be no load on your harness from opening shock, sure

***

If anything is hooked on your harness, how can there be NO load from it?

Am I missing something, my visualization skills aren't very good.

~ "Pack Fast, Pull Low... and Date Your Riggers WIFE!" ~

[tkhayes 126]

y'know, i am just going to step out of the conversation. I was offering simple advice based on years of experience and dozens of flag jumps. i do not need it to be over-analyzed, thanks anyway

TK

[GrabGrass 0]

Quote

y'know, i am just going to step out of the conversation. I was offering simple advice based on years of experience and dozens of flag jumps. i do not need it to be over-analyzed, thanks anyway

TK

Sorry if I pissed you off, not my intention.
I was serious about my question, it might seem like simple advise to you, but my not getting what you mean and asking for a clearer idea about your way of doing something souldn't get you mad?!

Accept my apology, and a , I won't ask anymore questions.

~ "Pack Fast, Pull Low... and Date Your Riggers WIFE!" ~

[tkhayes 126]

I'm not pissed off, I just get frustrated.

there is NO reason in the world one cannot hang a 10lb shot bag, with a 4x8' flag by a caribiner from your chest strap OR main lift web. If you gear is that weak, then you should probably buy a different rig.

I have never seen any damage from such a move.

And yes, you can hang D rings from your lift webs too, with a large 30x30 banner using a harness that connects to the lift webs/rear laterals and/or to the legstraps. I know because I have done it on many occasions.

And again, if your harness cannot handle that - get a different harness. The stresses are bugger-all compared to opening shock. You are talking about a hundred pounds hanging off a harness designed to handle a thousand of pounds of stress.

TK

[airtwardo 6]

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there is NO reason in the world one cannot hang a 10lb shot bag, with a 4x8' flag by a caribiner from your chest strap OR main lift web. If you gear is that weak, then you should probably buy a different rig.

I have never seen any damage from such a move.

And yes, you can hang D rings from your lift webs too, with a large 30x30 banner using a harness that connects to the lift webs/rear laterals and/or to the legstraps. I know because I have done it on many occasions.

Guess we're going to have to kind of agree to disagree on that one T.K.

Yes it can be done, yes I've done it...yes, I've most definitely seen rigs damaged because of it,
and NO...I won't ever do it again.

I've hung flags from every place you can, on a sport harness over the last 30 years....guess I'm getting TOO conservative.


Then again, my gear is subjected to more demo's than most...and that will increase the wear.
I have right at 300 flag jumps, but I prefer to jump smoke, it weighs less!(got just over 900 demos jumping smoke only)

Like I said above, I just want to put it out there for consideration.

~ If you choke a Smurf, what color does it turn? ~

[JohnRich 4]

I'm going to post here the rough draft of my document that I'm putting together, and I'm asking for any comments, suggestions, corrections, etc. that anyone can offer.

The perspective here is is to describe to a whuffo how to construct a demonstration jump flag or banner. So it has to be simple, and cannot presume any knowledge of skydiving or rigging.

---

How to build a flag for an exhibition parachute jump.

Introduction:

The purpose of this document is to explain to someone unfamiliar with the sport of skydiving, how to construct a display flag or banner that can be safely employed by a parachutist for an exhibition jump.

An exhibition parachute jump is one that is made outside of a normal skydiving operation, for the purpose of providing a visually pleasing performance for a crowd of spectators.

The flag or banner to be carried on this jump must meet certain requirements in order to provide for the safety of the parachutist who carries it, as well as for the crowd of spectators down below.

The safety aspects include security of the jumper while he is in freefall prior to deploying his parachute, security under canopy while the banner is deployed for display, security for the parachute landing, and safety for spectators on the ground who could be injured by the banner if it were to go astray.

With that in mind, let’s jump right in to the details.

Nomenclature:

For simplicity sake, I’ll use the term “banner” here to refer to either a flag of some type, or any other kind of display banner.

The key components are identified on the following photo:

(see the attached photo)

The banner is the actual display piece to be presented to the spectators in the aerial show.

The lanyard is a length of fabric webbing, which is the load-bearing component to which the banner is attached, and which is itself attached to the parachutist.

The lanyard is connected to the parachutist with a quick-release shackle, so that if anything goes awry at any time, a simple pull on the shackle will release the banner from the parachutist, to allow him to land safely.

A weight is located at the bottom corner of the leading edge of the banner, to hold the front edge firm against the blowing wind, so that the banner displays properly without folding in on itself.

(To be continued...)

[JohnRich 4]

Construction:

Now we’ll move on to the construction of the individual components of the exhibition jump banner.

The Banner:

Banners vary widely in size, from small enough to be stuffed down into the front of the parachutist’s jump suit, to giant ones as shown in the photo, above – that one is 20’ tall by 40’ long. The maximum size is limited by the amount of bulk that will fit in the deployment container, which is an old military surplus belly-mount emergency parachute container. (The exhibition jumper himself will provide this component, attach the banner to it, and pack the banner inside it. If the banner doesn’t fill the container properly, the exhibition jumper will add spacer foam to fill it out.)

The banner should also be sized so that the spectators on the ground can identify the logo and/or lettering, while the parachutist is at a height of several hundred feet above the ground.

An ideal ratio of height to length is about 1:1.5. If the banner is too long, the trailing edge will flutter wildly in the wind, and any logo or lettering on it may not be easily visible to the spectators.

A recommended banner size, then, which fulfills all of these requirements, would be one of the following:

1) 10’ high by 15’ long.
2) 15’ high by 23’ long.
3) 20’ high, by 30’ long.

How large you choose to make the banner depends upon the resources and time you are willing to devote to the construction. It should be no larger than 20’ x 30’, as that is about the maximum size that will fit into the deployment container.

The fabric from which the banner is constructed should be very lightweight, so that it will spread out and flutter easily in a 15-mph breeze. If the fabric is too heavy, it could potentially droop and not flutter horizontally properly. The other major consideration is bulk and weight, both of which need to be kept to a minimum for ease of operation by, and safety for, the parachutist. A lightweight nylon is the most common material used, weighing only about 1.1 ounces per square yard. This allows a large surface area to be packed-up into a small container. The colors are entirely your choice.

Nylon fabric should be cut with a “hot knife”. This tool is like a soldering iron with a razor blade on the end. The heated blade melts the edges of the nylon as it cuts, so that fibers are fused together to prevent fraying.

(See photo #1)

The fabric will come in a certain width on the bolt, or roll. To obtain the desired height and width, you will have to sew several lengths together to achieve the desired size. A recommended joint seam technique is shown to the right.

(See photo #2)

The outside edges of the banner should be rolled and double-stitched for strength, and to help prevent the fibers from fraying. A common edge finish pattern is shown to the right.

(See photo #3)

The type of thread to be used for the banner depends upon the durability needed. For a banner that will only be jumped once, lightweight thread can be used. If it is to endure repeated usages, then heavier thread should be used.



To add a corporate logo and/or lettering to the banner, there are several techniques.

For a single-use banner that only needs to withstand one jump, you can hang the blank banner fabric on a wall, draw the design on a clear plastic sheet, and use an overhead projector to display the image onto the banner. They you can trace the image outline onto the banner, and finish up with air brush painting.



For a multiple-use banner that will need to withstand repeated jump rigors, the logo and lettering can be cut from fabric and sewn in place. This is very durable, but also very time-consuming.

(To be continued - next up: the lanyard.)

[JohnRich 4]

The lanyard:

(Reference the attached image)

The lanyard should be constructed from a single length of 1-inch wide webbing, with a breaking strength of at least several hundred pounds. It should be lightweight and flexible, yet strong.

The lanyard will have a loop at the top end, for attachment of a shackle to connect the lanyard to the parachutist, and a loop at the bottom end for attachment of a weight bag.

None of the following measurements need to be matched exactly, but they should be close. So don’t worry if you’re off by a few fractions of an inch.

Both loops, top and bottom, can be made identical. So the following will describe how to make one loop, and then you’ll repeat the same procedure at the other end.

Start with a total of 20” of webbing above where the banner will be attached. At a point 12” up, fold the remaining 8” of webbing back onto itself. Stitch down 4” of webbing at the end, with heavy thread. This has to support the lanyard, banner and bottom weight. This will leave a 4” loop on each end, to which the shackle and weight will be attached.

This is the load-bearing component, so make it strong.

The banner can then be sewn to the lanyard to complete the assembly.

< types of stitching and thread? >

Here is a nifty bonus to this lanyard construction: it’s reusable! After the exhibition jump is complete, the banner stitching can later be unpicked to remove the banner from the lanyard, and the banner then hung for display proudly on your company premises. The lanyard can then be re-used at some future date for another exhibition jump with a different banner.

---

[JohnRich 4]

The weight bag...

You know what, I don't have a clue how to describe the building of a lead shot bag for about 7 lbs. of weight. You guys help me out! Please describe how you've built a simple, but strong, shot bag for a demo flag...

[SpecialKaye 0]

the last bag we built, we used a soft cotton that we were able to get a bit of flexibility and covered it with a cordura sleeve to keep the shot from leaking. it works great. We put grommets in the top and bottom of the cordura sleeve for an attachment to the flag and bridle.

hope this helps.
kaye

[JohnRich 4]

Quote

the last bag we built, we used a soft cotton that we were able to get a bit of flexibility and covered it with a cordura sleeve to keep the shot from leaking. it works great. We put grommets in the top and bottom of the cordura sleeve for an attachment to the flag and bridle.

Thank you for that idea - it sounds simple, and effective.

[skysurfcam 0]

http://apf.asn.au/Documents/Rigging/RACs/200Series/222B.pdf

Brother Wayward's rule of the day...
"Never ever ever go skydiving without going parachuting immediately afterwards."
100% PURE ADRENALENS

[bob.dino 0]

Go on, show off the flags you jumped with last weekend...

[JohnRich 4]

Quote

http://apf.asn.au/Documents/Rigging/RACs/200Series/222B.pdf

Nice!

I knew I couldn't be the first guy in the world to try and put this stuff down on paper.

Thank you very much for that contribution.

- John Rich

[skysurfcam 0]

Show off? Moi?

Ohh, you mean this...

C.

Brother Wayward's rule of the day...
"Never ever ever go skydiving without going parachuting immediately afterwards."
100% PURE ADRENALENS