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User avatar
By brian scharp
#396990
So is the wheel rotating directly on the base tube?
Yes. Maybe someone who's using them could chime in as to the wear and tear they may cause and prevent.
User avatar
By red
#396991
dbotos wrote:
Nice. So is the wheel rotating directly on the base tube? I always imagined some kind of sleeve that sat in between the base tube and wheel for the wheel to rotate on. With it directly on the base tube, I guess the plastic of the wheel would wear long before any damage to the base tube.For people with wheels on their gliders, do you do some kind of periodic (e.g. yearly) wheels-off inspection to check the condition of the the base tube, wheel bores, etc.?
Campers,

Periodic basetube inspections (at any intervals of time) may not be enough, really. For any round basetube with wheels, wear may be an issue, if there is no solid bushing (bearing) and the wheel rotates directly on the aluminum. Still, bending stresses caused by wheels are far more important there. If the wheels bend the basetube at some point, and the tube is straightened later, the damage (inside the metal) is concealed from any future inspection. The basetube is still damaged, and the damage may be dangerous. The problem is, the basetube looks okay, after straightening.

In either case, you can greatly reduce the risks of a basetube failure by installing a Basetube Safety Cable. I would want every flexwing glider to have one, if possible. This mod is not expensive, and can even be a one-evening DIY project. From my web page:

https://user.xmission.com/~red/#gm

:mrgreen:
User avatar
By sunnyjim
#397111
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User avatar
By sunnyjim
#397982
It just will NOT stop raining here in the NW. Have not been able to get outside to make a "how to" video yet but soon. Someone asked about measurement and I will be happy to share all that in the "how to" but hell, it just will not stop raining.
Went a little nutz last night making music....it turned out mediocre but I really don't care....I am posting it here because towards the middle is a good view of the "roll in landings" I am now doing.....later...SJ
[youtube]
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User avatar
By NMERider
#397983
sunnyjim wrote:....Went a little nutz last night making music....it turned out mediocre but I really don't care....I am posting it here because towards the middle is a good view of the "roll in landings" I am now doing..
:mosh: :mosh: :mosh: :thumbsup:
User avatar
By dbotos
#399679
As I'm approaching my H2, I'm realizing I'm going to need to buy a harness of my own at some point. That got me thinking about suprone again. I'd like to weigh that (and hopefully try it out) against a prone harness before plunking down the money on one setup or the other. I've got a local pilot that flies suprone who gave me his number to talk to him about it (I'll probably call him this weekend), but I thought I could pick everyone else's brain too and get a larger sample of opinions. So here are my questions:

1) Required components. From what I understand, you trade a traditional prone harness for the following:

a) PG harness
b) spreader bar with appropriate risers
c) add-on handles or bar setup that go on downtubes
d) stirrup setup for feet (optional)

Anything else I'm overlooking?

2) Parachute.

a) I like the idea of a front-mounted chute that you can pull with either or both hands. How well does a front-mounted chute do with suprone HG, from both the standpoint of normal flying (does it get in the way) and having to deploy it in an emergency (any more difficult than from a chest-mounted chute on a prone harness)? I was googling around and saw they make front-mount PG chute containers that also have an integrated instrument deck, which seemed like a nice feature.

b) How big of a parachute do I need? Are HG reserve chutes bigger than PG chutes to help carry the weight of the glider? My glider is a Wills Wing Falcon 3 195 with 10" pneumatic wheels and I'm about 175 lb in my birthday suit (which is not how I plan on flying).

3) Legs above base tube or below? Below has the advantage of lower CG and more roll control, but above seems like you could pull in more (the base tube doesn't get stopped by your body) and you have the option to wheel land. From Jim's videos, it seems like roll control is sufficient even being above the base tube. Any rule of thumb for how much clearance to keep between legs/butt and base tube? I've been using the fist-and-a-half to two-fists rule between my chest and the base tube when hang checking with a traditional training harness.

4) Launching and landing. Watching some more videos, it looks like people are launching from behind the risers so they can just sit back into flying position once airborne. For a foot landing with flare, does it generally work better to stay behind the risers or get up in front of them? If the latter, when is generally a good time to make the transition from behind to in front of the risers?

I'm sure I'll have more questions, but those are the big ones I can think of for now. My Falcon has a round speedbar base tube and round downtubes if that makes any difference to setting it up for suprone. I need to stick a cable in the base tube one of these days, like red mentioned.

Thanks,
David
User avatar
By dbotos
#399681
Thought of another couple:

5) Harness features. What features would one look for (or avoid) in a PG harness to use on a hang glider? Assume recreational H2 kind of flying, mostly mountain sites. If you could have a custom suprone HG harness made, would it incorporate anything not available on (or somehow be significantly different from) available PG harnesses?

6) Truck towing. Where you launch from the back of a pickup truck with a payout winch. Anyone done that suprone? If so, how did the bridle and release setup go.

Jim - I hope I'm not hijacking your thread. Let me know and I can start a new one if so.

Thanks,
David
User avatar
By DMarley
#399682
Wheels on control bar:
I have the 8" Finsterwalder pneumatic tire/wheel/bushing assembly on my Falcon 3 195.... though slightly modified after I discovered the anodizing beginning to slightly wear. I had purchased the glider from a friend who had flown it five times after he purchased it new, along with the wheels, and I replaced the bearing surface after my first flight.
The wheels come with a black plastic bearing insert on each side of the wheel. These 'bearings' are so tight that they do not rotate within the wheel, but they do rotate on the control bar, causing the anodizing to wear.
I pulled these bearing off the wheels and substituted an approximately 3" long piece of schedule 20 1.25" diameter PVC pipe as the bearing surfaces, one per wheel (Schedule 40 will not fit). These fit quite loosely within the wheels, as well as over the control bar. I wrapped the control bar with some vinyl electrical tape so that the PVC pipe sections would have a friction fit. The wheels are held on the PVC pipe with PVC pipe couplings that were cut on the band saw into 3/8" long rings, which in turn are glued onto the 1.25" PVC pipe on both sides of the wheel with PVC cement. I can knock these wheel assemblies on and off the control bar in a mere second or two for easy storage and transport.
In countless flights, these have held up perfectly, and the rare rough-landing impacts are not only softened by the pneumatic tire, but also distributed better by the layers of vinyl tape and the PVC 'bearing' surfaces.

As for suprone flying position ...
To each his own. :roflcat:
#399685
b) How big of a parachute do I need?
HES Q 330 would be just fine. If you don't have Dealer in your area send me a PM. I can ship direct.

8)
User avatar
By dbotos
#399688
Doug,

My wheels are currently rotating directly on my base tube:

viewtopic.php?f=16&t=35450

I'm planning to make full-width HDPE bushings to go in the wheels to help spread things out. At some point, I may make it like you're talking about where the wheels rotate on some sacrificial piece that is cheaper to replace than the whole base tube.

David
User avatar
By dbotos
#399690
As part of considering the suprone position/setup, I thought it might be good to discuss some of its potential drawbacks:

1) Drag. The sitting position (as compared to prone) presents a larger frontal area to the airflow and most likely a higher drag coefficient (i.e. not as streamlined). Could be lessened somewhat by getting XC/race style PG harness.

2) Downward visibility. Reduced since your legs are in front of you. Guessing you can just lean your head over to one side if you need to see below you better. Paraglider pilots would face the same issue and they seem to manage.

3) Added weight / setup time. Spreader bar and downtube handles adding weight. Attaching and removing downtube handles would add a little bit to setup/breakdown time.

4) Harder to try out. Being less common, you'd either have to invest the money in a setup of your own (probably not economically feasible unless you could find a good, cheap used PG harness (maybe resell later, if not your cup of tea) and then DIY the rest of the parts) or find someone within a reasonable distance willing to let you try their setup. Further potential difficulty with the latter if their body side and/or glider significantly different than yours (e.g. big pilot trying to fit in a small harness, downtube handles don't fit you glider correctly, risers too long or short, etc.).

5) Stigma. It's certainly not the mainstream way of flying. Some probably view it as being for old pilots or those with a bad neck and/or back. Like Doug said, to each his own. I'd like to try both ways before investing in a setup. Who knows, maybe I'll eventually buy both and then just decide which way to fly that day once I get on site and assess conditions and mood. Interesting listen here on the Threshold Model of Collective Behavior (which I happened to hear on the podcast while driving on one of my trips to go train):

https://www.thisamericanlife.org/radio- ... act=1#play
User avatar
By TjW
#399706
I'm not convinced drag in a supine rig is necessarily greater than prone for one reason: most people don't fly with their heads down all the time. There may be a few pilots that do, but the majority I see don't.
Prone the way most people fly it is better than upright seated, but a comfortable head-slightly-up supine rig is unlikely to be worse than head-slightly-up prone.

For visibility and weight, you've got a point. Visibility upward is going to be restricted by the relatively long keel lengths of the lower aspect ratio gliders this kind of flying is usually suggested for. On something like an ATOS, it's possible your head would be far enough behind the trailing edge that you could see up.

If you have to re-rig a glider to fly supine or suprone, then yes, it would be a hassle to try out. If all you do is clamp something to the control bar and borrow a harness, then demo flights on your own glider become possible.
User avatar
By dbotos
#399723
It looks like some European manufacturers have different wire sets to change the rake of the control frame. I would just keep mine stock.

I talked to the local pilot who flies suprone this weekend. He offered to let me try out his harness. Which means I'd either need to be experienced enough to fly at the local mountain sites or if he came out to where I'm training (which he did mention might be a possibility).

In the meantime, I've been looking at spreader bar designs. It'd be nice to make one out of somewhat more aerodynamic tubing. Maybe one of these elliptical / kayak cross sections with the stiffening ribs inside:

https://sc01.alicdn.com/kf/HTB15ii_HVXX ... tangle.jpg
User avatar
By dbotos
#400158
Jim,

Good stuff. :thumbsup: Looks like the racier PG harness still has okay clearance from the rear wires while launching (I had been wondering that about harnesses that have the big back protectors or the streamlined tail). Guess that would be a good thing to check on the ground with each particular setup. Is that an Avian brand spreader bar in your setup?

http://www.avianonline.co.uk/spreader-p-1882.html

David
#400276
yes, but probably going to end up building our own harnesses for Suprone. Reason is two fold. 1. all that padding under the pilot in the PG harnesses and that large area under the pilot for a parachute are not really needed if we are flying suprone above a base tube with wheels are they? :punch: No, not really, and if all that stuff was gone would I have to turn a base tube downward so much to get back my roll control?. Probably not...and that would give my wheels more clearance! I like it.
Also, ALL these PG harnesses, because our lines do not spread outward like a PG does in launching but two lines run up and over our shoulders kinda "drop" you into the seat on that last step. The reason for this is the main suspension lines are running OVER the shoulders and BACK towards ones hips. AS soon as the legs come off the ground...."plop'....the hips swing forward.
Remedy for that Scotty mentioned in the above video...a hinge plate about three inches forward of the hip built into a carbon fiber seatplate.....I agree....that is going to make launching feel totally positive throughout the launch run....BTW...I did put out another video...shorter...here it is...
:wtf:
User avatar
By Nicos
#400280
Nice one, I have also ordered the Avian spreader for the same reasons (BTW, don't google "spreader bar" at work BTW!).

Didn't Finsterwalder used to make a comfy supine/suprone harness?
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