Water ballast filling contraptions

908 views
Skip to first unread message

Jim M

unread,
Dec 24, 2024, 12:22:25 PM12/24/24
to RAS_Prime
I'm considering my options to do a fill up.  As far as I know the ballast bags are 25 year old originals and have been used successfully in the past but I haven't tried them out yet.  I figured that I'd fill them up to my max gross, test out the drain system then check for leaks and go fly.

The DG-800B flight manual has some good advice but is curiously quiet on exactly how to get the water in there.

I'd like to see what kind of plumbing ideas people have put together to fill up a measured amount without blowing up the wing.  It would be ideal to have something that would fit in the glider, maybe disassemble-able since I kinda need to taxi to the water hose on my way to the runway.

I was thinking something like this with an open ended vertical riser pipe to prevent over-pressure.


Thanks!

Mark Mocho

unread,
Dec 24, 2024, 2:29:38 PM12/24/24
to RAS_Prime
I have built a number of standpipe systems for myself and others. They are made from PVC with a sight gauge to prevent overflow from the top of the pipe. They come apart with no tools for trailer storage. For water measurement, I have tried a number of the digital types, from cheap sprinkler counters like the one you listed to expensive digital types as sold by sailplane dealers. Invariably, the digital meters vary widely in accuracy, especially at the low flow rates we use to fill ballast tanks or bags. I hooked several in line and filled a known volume (15 gallons). The variance was from 11 to 17 gallons.

Since wing repair after a screw up is VERY expensive, I elected to discard the digital devices and bought an actual metal-body flow gauge from Craggy Aero. I just looked for it on his website, but do not see it. Craggy used to provide the meter with the fittings necessary to connect to a garden hose. It is very accurate, even when the flow is just a trickle.

If you are interested in a takedown standpipe, let me know and I will provide a photo. I could also be talked into fabricating one.

Mark Mocho

unread,
Dec 24, 2024, 2:49:26 PM12/24/24
to RAS_Prime
Note: Some wing bags do not have a vent, which makes it more complicated to fill because there is no way for air to escape and the bag can expand to fit the space available before the desired quantity of water is filled. Check with others to find the best method to fill these. A standpipe will prevent overfilling and over pressurizing the wing, but it can be tricky to get the right amount in the wing.

Jim M

unread,
Dec 24, 2024, 6:16:59 PM12/24/24
to RAS_Prime
Good stuff, thanks Mark.  I would like to see some photos or a drawing maybe if you have them handy.  I found this one, good to as little as .25 gpm:


But, I wonder if using a hose at all is a good idea given the risk?  Maybe I'd be better off with a funnel and a 5 gal bucket, but that sounds tedious.



On Tuesday, December 24, 2024 at 10:22:25 AM UTC-7 Jim M wrote:

Mark Mocho

unread,
Dec 24, 2024, 7:27:05 PM12/24/24
to RAS_Prime
Craggy Aero no longer offers the water meter, but it is here on Amazon:


Higher price than when Craggy offered it, but that was several years ago. It's still cheaper than the one from McMaster, and the DLJ meter has a metal body and already has the garden hose fittings. To keep the flow down to a rate that the wings or wing bags can take, I use a small ball valve on the end of the hose on the inlet side of the meter. The outlet goes into the standpipe and any air from the hose goes up the standpipe and not into the wing. The standpipe is about six feet tall, or around 40 inches above the wing. Therefore, it cannot get enough head pressure to overstress the wing if the bag gets completely full. It only takes a few psi to break the wing! Remember, it's not the "P" it's the "SI"

I use the ball valve on the hose to regulate the flow, keeping the level in the standpipe just below the open top of the pipe. The water will overflow out the top long before the pressure gets to a dangerous level. A clear vinyl tube on the upper section acts as a sight gauge so you can see how full the standpipe is. This system has worked well for me for several years. I've built the system for several other pilots, and they all like it. The only hassle is that the water meter cannot be reset to zero, so you have to remember what the reading was when you started filling and know when to shut off when the desired volume has been reached. That means you have to use third-grade arithmetic. At least it was third grade when I was in school. Today, it's probably High School level math.

I'll take a couple of pictures next time I am out at the airport.

Nelson Howe

unread,
Dec 25, 2024, 10:07:30 AM12/25/24
to RAS_Prime

Jim M

unread,
Dec 25, 2024, 12:24:07 PM12/25/24
to RAS_Prime
I like the simplicity of this, but I have to wonder how long I'll need to stand there holding my bucket?  Or, if I spill some then who knows how much got in there.

IMG_3594.jpegIMG_3596.jpeg

Dennis Vreeken

unread,
Dec 25, 2024, 4:00:12 PM12/25/24
to rasp...@googlegroups.com
Jim , that was the system I had on the Lak 17 that I owned previously. Just needed a water meter on the fill line and it worked great . Merry Christmas!     Dennis
Sent from my iPad

On Dec 25, 2024, at 9:24 AM, Jim M <jimmur...@gmail.com> wrote:

I like the simplicity of this, but I have to wonder how long I'll need to stand there holding my bucket?  Or, if I spill some then who knows how much got in there.

<IMG_3594.jpeg>
<IMG_3596.jpeg>

--
Thanks for using RAS_Prime!
---
You received this message because you are subscribed to the Google Groups "RAS_Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rasprime+u...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rasprime/a8f5c832-a518-4f35-b9e9-d7cc8690c761n%40googlegroups.com.
<IMG_3596.jpeg>
<IMG_3594.jpeg>

Jim M

unread,
Dec 25, 2024, 8:39:58 PM12/25/24
to RAS_Prime
Good idea, eliminate the bucket.  I found this one on W&W, all I would need is a short hose after the meter.  Merry Xmas to you!

Paul Remde

unread,
Dec 25, 2024, 9:47:33 PM12/25/24
to RAS_Prime
Hi,

I sell a complete water meter kit with the needed output "backpressure" hose, and a volume/weight conversion table.

I tried selling low-cost garden hose water meter systems for a while, but wasn't happy with the performance.

Happy Holidays,

Paul Remde
Cumulus Soaring, Inc.

Mark Mocho

unread,
Dec 26, 2024, 6:34:45 AM12/26/24
to RAS_Prime
IMI Gliding sells an interesting programmable water system that will fill to a pre-set level. Kind of expensive, but it is an interesting product. However, I would not trust any "automatic" filling device without a reliable pressure shutoff. If it doesn't shut off when the wing reaches capacity, the result could be a VERY expensive "CRACK!" noise as the wing splits. This can be avoided by running it through a standpipe as mentioned earlier.

I am going to take a couple of photos of my standpipe today and will post them here on RAS_Prime soon.

Watermeter - automatic water ballast meter | IMI Gliding

Mark Mocho

unread,
Dec 26, 2024, 9:25:30 AM12/26/24
to RAS_Prime
One thing I noticed about the Great Plains Industries (GPI) digital water meters is that they became less accurate after a few years with unfiltered or high mineral content water. (hard water) Moriarty water is pretty lousy when it comes to mineral content. I don't make my coffee or cook with it for sure! And I hate washing my glider with it too! After about three years of using a GPI meter, the turbine wheel inside had started to stick, and it got so bad that it was only registering about 70% of the water flowing through it. This was at a flow rate of 2 gallons per minute, which is about as fast as my wing bags will fill without overflowing the standpipe. I couldn't figure it out until I hooked it in line with another new GPI meter and tested them by filling three measured five-gallon buckets. I also learned to make sure ALL of the water was emptied from the ballast system before trying to refill. Occasionally, if I hadn't initiated the dump early enough on final glide, I could still have residual water draining after landing and rollout. As I came to a stop with one wing down, there would sometimes be a couple of gallons left in the low wing. Something to watch for!

Matthew Scutter

unread,
Dec 26, 2024, 3:14:43 PM12/26/24
to rasp...@googlegroups.com
I use the Aquator - https://swiss-sailplane.ch/wp-content/uploads/2023/08/Flyer.pdf
I use it inline with a hose that is less than half the diameter of the top-mounted ballast holes on my glider so I don't believe there is real risk of the wing blowing up if it fails. Why some manufacturers insist on making you fill from below with elaborate contraptions, I'll never know.

Mark Mocho

unread,
Dec 26, 2024, 3:33:19 PM12/26/24
to RAS_Prime
My standpipe. About 78 inches tall overall. The middle joint in the vertical tube is just a slip fit. The lower joint is threaded, but a slip fit would probably work. Just keep the joint lubed with silicone grease or Vaseline to keep it from sticking. The inlet is about waist high and is a 5/8-inch hose barb. Note the garden hose on the water meter that slips over the hose barb. On the inlet side of the meter, I have a garden hose type shutoff valve to regulate the flow and keep the water up towards the top of the standpipe, monitoring the level in the 3/8-inch clear vinyl tube sight gauge. Works very well.
s1.jpg
s2.jpg

Jim M

unread,
Dec 26, 2024, 6:29:47 PM12/26/24
to RAS_Prime
Thanks for photos, could it be shorter?  I’m wondering if a handheld version would work, as long as the riser opening is higher than the wing.  But that may limit the flow and take forever, I guess?

I do like the idea of Aquator though.  It sounds like a ballast filling superhero!

Mark Mocho

unread,
Dec 26, 2024, 8:37:54 PM12/26/24
to RAS_Prime
Yes, it could be shorter. I have it that tall because it allows for slightly faster filling due to the increased "head pressure" imparted by the extra height. How much faster? Probably not enough to worry about, but it makes me feel like I am actually not wasting the extra thirty seconds per wing when the cumulus are popping. A handheld version could be possible, but it seems like I nearly always have to do something with the hand that isn't controlling the flow valve, so I would end up needing another arm, which would be hard to deal with in the cockpit. Plus, it would add weight.

One thing to remember when filling: there is a certain amount of water that fills the system before the flow actually reaches the wing bag. In my case, it is about 3/10 of a gallon, so I allow for that before calculating how much I want to add as ballast. My wing bags will take about 18 gallons per side, but I generally only fill to 12 gallons (each) plus 1 gallon in the tail tank for CG adjustment. This takes me up to maximum allowable weight (1,003 lbs.) I don't much like how it flies when it is heavier, but sometimes when the day is really rockin' I wish I had some more ballast. Like, maybe another arm.

Eric Greenwell

unread,
Dec 28, 2024, 9:10:32 AM12/28/24
to RAS_Prime
The bottom fill gliders are usually ones with bags instead of tanks, but not always. It does save the cost of installing the top fill port if you use the dump port to fill the tank.

Chip Bearden

unread,
Dec 30, 2024, 11:24:54 PM12/30/24
to RAS_Prime
I have bags in my ASW 24 and dealt with them in my old LS3 and Libelle 201s. Three items I haven't seen mentioned:

1. There always seems to be some air left in the bags after you dump. I suck the air out using a handheld vacuum. I close the valves after exhausting the air with the vacuum still running, then open them only after letting water into the fill hose to minimize the amount of air I inject into the bags. This is less to ensure a complete fill (mine are the larger set for 24s, so about 44 gal total, which I have seldom used) than to minimize the air that might be entrapped in the bags that could expand as the altitude increases.

2. Depending on whether you fill wings level or the "down" wing, the difference in head can be significant and result in a different pressure in the bag/wing with a standpipe of a given height.

3. For years, I left the bags in the wings year around. I discovered trailering long distances was wearing certain spots on the outer surface of the heavy-duty bags. So now I install them only after I arrive at a contest and remove them before I trailer home. It's about 30 min for each operation. As a lazy, aging, Eastern pilot, I seldom use ballast (only at wet contests) so frequently a year or more will go by without installing them. 

I almost always fill one wing at a time (the down wing) even though it means having to prop the first wing up for a while until there's enough water in the second wing to overbalance the first one. My system has separate valves for each wing but they connect to a common dump port, where I insert the fill hose. The last step before I disconnect is to level the wings carefully, then close the valves, hoping they will balance on the line. That said, occasionally one wing will still be slightly heavier. Either dump a little from that wing, or make VERY sure the wing runner balances--not levels--the wings before the takeoff roll begins. Crosswind takeoffs with ballast, especially partial ballast, are another subject. 

FWIW, I use a water meter I acquired in Hobbs at the nationals back in 1992. An employee of the local water company was selling them (legally, I'm sure!!). It's the one they used to connect homes to the water system: metal, very substantial, very accurate, and almost immune to the impurities in well water. You can't zero it so you have to note the beginning reading when you start to fill, and then again after you finish the first wing (full or partial). 

Chip Bearden
ASW 24 "JB"

Jim M

unread,
Dec 31, 2024, 11:30:58 AM12/31/24
to RAS_Prime
It looks like most newer gliders have integral tanks for a bunch of good reasons.  I probably should pull the bags and inspect them at least, maybe a bench test too.  I wonder if one could have bags made with baffles of a size and shape so that cracking the wing skin would be less likely?

Mark Mocho

unread,
Dec 31, 2024, 2:06:00 PM12/31/24
to RAS_Prime
Baffles won't prevent the expansion of overpressure. The area of the bag when overfilled pushes against the top and bottom of the wing and will delaminate the top and/or bottom skin from the spar. The expansion can also split the leading edge. It only takes a few psi to cause the damage.

John Ackerson

unread,
Dec 31, 2024, 8:03:12 PM12/31/24
to RAS_Prime
I created my own water buffalo using a 12v water pump designed for an RV with a pressure valve.   I control the water flow with a 1" sprinkler ball valve hooked to the water flow meter.    I purchased a garden cart off of amazon and found the used 60 gallon tank on the Facebook marketplace.  My 60 gallons tank can fill my glider twice.   I have a 20ah lithium style glider battery that powers the pump.   I use a electric water meter to measure the exact volume for each wing and never wait for the bags to be full as I would be overweight in my DG800S.   My engineer brain decided to make the most complicated solution possible with the quickest and most convenient fill time possible.   Most likely excessive design but it was a fun build and engineering challenge. 
IMG_6372.JPEG

*Eric Greenwell1*

unread,
Jan 1, 2025, 9:22:56 AM1/1/25
to rasp...@googlegroups.com

Your solution avoids the need for a vehicle to take the water to the glider, or to take the glider to water - a good feature. When I was flying contests, I could always take a vehicle to the glider, so I used an air mattress of the correct volume, placed on the roof for the "perfect" head pressure, or on the hood of my truck when I had a slide-in camper. The air mattress cheap and easy to roll up and carry in the trailer.

Jim M

unread,
Jan 1, 2025, 11:04:38 AM1/1/25
to RAS_Prime
Does your set-up limit the pressure in some way, or have you done the math?

Daniel Mockler

unread,
Jan 1, 2025, 11:07:06 AM1/1/25
to rasp...@googlegroups.com
mgh

From: rasp...@googlegroups.com <rasp...@googlegroups.com> on behalf of Jim M <jimmur...@gmail.com>
Sent: Wednesday, January 1, 2025 9:04:38 AM
To: RAS_Prime <rasp...@googlegroups.com>
Subject: Re: [RAS_Prime] Re: Water ballast filling contraptions
 
--
Thanks for using RAS_Prime!
---
You received this message because you are subscribed to the Google Groups "RAS_Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rasprime+u...@googlegroups.com.

*Eric Greenwell1*

unread,
Jan 1, 2025, 11:32:53 AM1/1/25
to rasp...@googlegroups.com

The height of the roof minus the height of the glider fill point sets the pressure. With my mini-van and my gliders, that was about (5' - 2.5') = 2.5' of water column, or about 1 psi (1 foot column height produces 0.43 psi). That's not a fast fill, but it's safe. On my motorhome, I'd mount a tank on the ladder, and a foot or two higher to speed the filling.

--
Thanks for using RAS_Prime!
---
You received this message because you are subscribed to a topic in the Google Groups "RAS_Prime" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/rasprime/4zI8tGUBoeU/unsubscribe.
To unsubscribe from this group and all its topics, send an email to rasprime+u...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rasprime/f97e3894-1ecf-4330-961e-90f43acd20ddn%40googlegroups.com.

ka...@uplink.net

unread,
Jan 1, 2025, 12:08:28 PM1/1/25
to rasp...@googlegroups.com

The height of the water source above the glider wings doesn’t matter as long as there is no sealed connection. I use a truck inner tube with the supply nozzle inserted loosely into the wing fill ports.

 

If the connection to the tank is solid you can add an L with the outlet about three feet above the wing to limit the pressure.

 

From: rasp...@googlegroups.com <rasp...@googlegroups.com> On Behalf Of *Eric Greenwell1*
Sent: Wednesday, January 1, 2025 9:23 AM
To: rasp...@googlegroups.com
Subject: Re: [RAS_Prime] Re: Water ballast filling contraptions

 

Your solution avoids the need for a vehicle to take the water to the glider, or to take the glider to water - a good feature. When I was flying contests, I could always take a vehicle to the glider, so I used an air mattress of the correct volume, placed on the roof for the "perfect" head pressure, or on the hood of my truck when I had a slide-in camper. The air mattress cheap and easy to roll up and carry in the trailer.

--

Thanks for using RAS_Prime!
---
You received this message because you are subscribed to the Google Groups "RAS_Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rasprime+u...@googlegroups.com.

Chip Bearden

unread,
Jan 1, 2025, 2:27:24 PM1/1/25
to rasp...@googlegroups.com
Agreed. The solid connection is more likely with bags than hard tanks, I think, but back in the old days I used 5-gallon cans and a funnel to fill the bags in my LS3, which avoided any chance of overpressurizing. That was when 20 gallons was a full load. Hahaha. I've never had hard tanks but a fill hose loosely inserted into the upper fill port makes a lot of sense. I've also found that the natural gum rubber hose I insert into the lower fuselage dump port pops out instantly when the pressure rises but I don't rely on that to keep my wing skins attached. 

I also used a truck inner tube (works great, with very low risk of overfilling the tube from the spigot; it just gets bigger, alarmingly so if you walk away and forget it) and an air mattress. I had a solid connection by then and can't recall the specs but I recall measuring to confirm that I wouldn't exceed the allowable "head" with the inner tube on the roof of my van and the wings level, but might come close if one wing was down. Fairly soon, I added a standpipe T'd into the solid connection to avoid even the possibility of overpressurizing the system.  

I didn't start filling from a spigot at the launch airport until that became common practice and the organizers began to provide enough fill stations for the entire field (kudos to Bruno, et al., at Nephi for running pipes out to the tiedown lines so no glider was ever more than a T-connection and a couple of garden hoses from filling!). 

We haven't talked about it but one hazard of the inner tube or mattress on the rooftop is that a hard stop when pulling up to the glider can cause the water container to roll off the roof onto the vehicle hood (from experience, awkward) or even the ground (from experience, even more awkward). Since there's no way even a handful of strong men are going to lift 350 lbs. of flexible rubber inner tube back onto the roof, from experience, it is possible for several people sitting on the full inner tube to create enough pressure to eventually fill up the glider, especially if they can be persuaded to lift the partially emptied container as it becomes lighter to finish filling. :)  

This could spark the recounting of any number of "amusing" (or horrific) water ballast stories, including ones like a friend who plugged a hose into the fill tube of an LS4 (with bags, IIRC) and popped the wing skins off the spar on a practice day at the nationals. He managed to get it repaired in time to fly the contest.

Chip Bearden
"JB"


You received this message because you are subscribed to a topic in the Google Groups "RAS_Prime" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/rasprime/4zI8tGUBoeU/unsubscribe.
To unsubscribe from this group and all its topics, send an email to rasprime+u...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/rasprime/017801db5c6f%24c56e7f80%24504b7e80%24%40uplink.net.
Reply all
Reply to author
Forward
0 new messages