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#1
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
I've been told (and witnessed) that aerotow on CG hook is initially difficult for someone who has trained for aerotow with a "nose hook" (aka hook-forward-of-CG). Suppose this CG-hook-newbie were to take winch tow training (with CG hook). Would the winch training reduce the initial difficulty of a CG hook aerotow?
Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? What sorts of misadventures are reasonably attributed to aerotow on CG hook? I understand why CG hook is superior for winch tow. No need to rehash that explanation. |
#2
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On Thursday, May 24, 2012 7:54:00 PM UTC-7, son_of_flubber wrote:
I've been told (and witnessed) that aerotow on CG hook is initially difficult for someone who has trained for aerotow with a "nose hook" (aka hook-forward-of-CG). Suppose this CG-hook-newbie were to take winch tow training (with CG hook). Would the winch training reduce the initial difficulty of a CG hook aerotow? Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? What sorts of misadventures are reasonably attributed to aerotow on CG hook? I understand why CG hook is superior for winch tow. No need to rehash that explanation. There is increased risk that come from the directional squirliness. Can you reduce this with training. Sure. Can you eliminate any risk, no. Can you reduce it enough to feel comfortable. Maybe, but that is a personal risk decision, not something somebody else can tell you. But I've seen a few departures to the weeds with folks aerotowing with a CG hook. The attention getting ones involve crosswinds and narrow strips and/or tall grass... ending in ground loops. That cross wind handling, need to be ready to quick release etc. should be things to look at with an instructor. Its not clear what you are flying or where, but some flight manuals do prohibit aerotowing with a CG hook (e.g. my ASH-26E does). Darryl |
#3
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On May 24, 8:54*pm, son_of_flubber wrote:
I've been told (and witnessed) that aerotow on CG hook is initially difficult for someone who has trained for aerotow with a "nose hook" (aka hook-forward-of-CG). *Suppose this CG-hook-newbie were to take winch tow training (with CG hook). *Would the winch training reduce the initial difficulty of a CG hook aerotow? Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? What sorts of misadventures are reasonably attributed to aerotow on CG hook? I understand why CG hook is superior for winch tow. *No need to rehash that explanation. Most glass two seat trainers (Grob, ASK-21, etc.) have both nose and CG hooks so you can arrange to get some flight instruction in one aero towing with the CG hook. Some countries prohibit aero tow with CG hooks or require special training to do so. I can't say that 100% of the dangers go away with training and experience but very nearly so. I think winch training will improve any pilot - sometimes substantially and not just with a CG hook. For pilots trained on aero tow, the main danger with a CG hook is a ground loop on the takeoff roll - a nose hook tends to keep the glider rolling straight if a wing drops but the effect is small. If seen many if not more ground loops with nose hooks. A glider aero towing with a CG hook can easily climb above the tug creating a very dangerous situation for the tug pilot but these upsets happened primarily to pilots who had mostly winch experience and little aero tow experience. It's as easy to stay in position behind the tug but you have to be aware of the need to do so - you have to really fly formation on the tug. The rope will not pull you back into position. |
#4
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On 5/24/2012 7:54 PM, son_of_flubber wrote:
I've been told (and witnessed) that aerotow on CG hook is initially difficult for someone who has trained for aerotow with a "nose hook" (aka hook-forward-of-CG). Suppose this CG-hook-newbie were to take winch tow training (with CG hook). Would the winch training reduce the initial difficulty of a CG hook aerotow? No, and I suggest it may make you worse at aerotowing, because you learn to put the glider in a steep climb. "Kiting" on tow is a bad problem; "kiting" during a winch launch is normal operation. Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? No, but you can significantly reduce the risks with training and experience. What sorts of misadventures are reasonably attributed to aerotow on CG hook? The worst is the increased potential for the aforementioned kiting; the rest tend to happen on the ground with a chance for damage, but not less risk to people. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#5
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On Friday, 25 May 2012 03:54:00 UTC+1, son_of_flubber wrote:
I've been told (and witnessed) that aerotow on CG hook is initially difficult for someone who has trained for aerotow with a "nose hook" (aka hook-forward-of-CG). Suppose this CG-hook-newbie were to take winch tow training (with CG hook). Would the winch training reduce the initial difficulty of a CG hook aerotow? Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? What sorts of misadventures are reasonably attributed to aerotow on CG hook? I understand why CG hook is superior for winch tow. No need to rehash that explanation. Also, CG hooks can back release if you get a lot of slack in the rope. The manual may suggest a method for blocking the back release - make sure you remove it before winching. |
#6
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
In the spirit of embarrasing admissions here.
I transitioned to aerotow at around 300 flights. Only ever winch launched for the first part of my career. By then I was a happy and reasonably competent Std Cirrus driver. (no nose hook) I found aerotow difficult to get right because of over controlling the Grob Twin Astir - I was not used to the momentum in those heavy wings, and we were towing on CG hook so that I would be used to it when I transited to the Cirrus - and we wallowed all over the place behind the tug. To the despair of my instructors who no doubt started wondering how I had flown solo... Trying to simultaneously transition to aerotow, on CG hook, with a completely new class of glider to me - put me back at ab-initio competence for a while. To shorten a long and frustrating experience - the winch experience on the CG hook was little help. In fact the winch training can impede progress. If you can fly aerotow competently the CG hook makes it only a little more difficult. The aircraft will not self correct nearly as much as on nose hook, so sloppy flying will be rewarded with diverging excursions. Then the good news - to get back to your questions - as soon as the CFI let me go fly my own nimble little Cirrus it all went a lot better. There is no substitute for experience - on type, and yes training will help. The control harmony of what you are flying will influence the outcome and what really counts is experience with aerotow in general, and experience with what you are flying. Specifically the ability to fly very precisely, and experience on the type you plan to fly on the CG hook. CG hook specific misadventures: If you get too high - especially with some designs, there is danger of kiteing. On the ground run, crosswinds are much more of an issue. No correcting force on the nose so the grass at the side of the runway exerts an inexorable attraction. You have to be on top of lateral control all the time and be prepared to release the moment if goes sideways. Lateral diversions on the ground run that are recoverable on nose hook tow will result in a ground loop on the CG hook. If your mount has airbrakes behind the CG you can help with directional stability at any point by cracking them open. Nose up pitch - the CG hook is below the centreline, so jerks on the tow rope will tend to rotate the nose up. Especially on a light high drag single seater like a Ka8. (this is one way to go kiteing) (PS: The Grob STILL flies like a pig on CG hook - just my biased personal view.) On 2012/05/25 4:54 AM, son_of_flubber wrote: I've been told (and witnessed) that aerotow on CG hook is initially difficult for someone who has trained for aerotow with a "nose hook" (aka hook-forward-of-CG). Suppose this CG-hook-newbie were to take winch tow training (with CG hook). Would the winch training reduce the initial difficulty of a CG hook aerotow? Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? What sorts of misadventures are reasonably attributed to aerotow on CG hook? I understand why CG hook is superior for winch tow. No need to rehash that explanation. -- Bruce Greeff T59D #1771 |
#7
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
CG hook specific misadventures: On the ground run, crosswinds are much more of an issue. No correcting force on the nose so the grass at the side of the runway exerts an inexorable attraction. You have to be on top of lateral control all the time and be prepared to release the moment if goes sideways. Lateral diversions on the ground run that are recoverable on nose hook tow will result in a ground loop on the CG hook. Yes, to all of the above. Plus, the glider type seems to make a difference. The Pegasus 101A that I used to own a piece of always wanted to head for the weeds in any kind of cross wind (and I've seen two others get damaged like that). OTOH, the LS6-b that I now fly simply tracks straight under the same conditions - no fuss. Be sure that the glider is perfectly aligned before the take off roll on a normal launch. On an unassisted launch (read 'land out'), I put the down wingtip slightly ahead, expecting the tip drag to straighten me out by the time the wings level. How much of a lead depends on the surface type. A nose hook is clearly superior for aero tow. Tony "6N" |
#8
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On May 24, 7:54*pm, son_of_flubber wrote:
Do the difficulties/danger of aerotow with CG hook go away completely with training and experience? What sorts of misadventures are reasonably attributed to aerotow on CG hook? It all depends on the glider. There is no generic answer. To put my reply in context I have 456 aero tow launches with CG hook in ASW19b and 243 aero tow launches with CG hook in ASW 28. Neither glider has any issue at all with pitch stability or directional control while in flight. The ASW 28 has no issues at all with directional control on the the ground. However, the ASW 19b with its small tail wheel could be tricky in moderate to strong cross winds at the start of the takeoff roll. I have no way of knowing how much better it would have been with a nose hook. With proper positioning of the glider and with proper pilot technique I was able to make takeoffs in any wind condition other gliders or pilots could handle. Unless you are planning to fly a vintage glider that is prone to kiting, and if you are competent at aerotow with a nose hook, the only issues you are likely to experience with a CG hook a 1. Risk of rope over-run and back release if the tug takes up slack quickly. That's easily avoided by using the wheel brake. 2. Inadequate directional control at start of takeoff roll with cross winds. This can be reduced by positioning the glider to compensate or by using a wing runner who understands the problem and helps to keep you straight. The other side of the coin is that, as a tow pilot, I have been subjected to moderate to severe abuse by pilots learning to fly the Std Cirrus. As I said it depends on glider type and pilot skill level. A final data point - My ASW 28 has both a forward belly hook and a CG hook. I choose to always use the CG hook for aerotow. Andy (GY) |
#9
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On May 24, 10:18*pm, Eric Greenwell wrote:
On 5/24/2012 7:54 PM, son_of_flubber wrote: No, and I suggest it may make you worse at aerotowing, because you learn to put the glider in a steep climb. "Kiting" on tow is a bad problem; "kiting" during a winch launch is normal operation. A pilot would have to be pretty stupid to let that happen. (Learning is where you ADD knowledge - not replace what was already there.) Learn winch launch - you WILL become a better pilot. |
#10
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Compare/Contrast: CG hook on aerotow vs. CG hook on winch
On May 24, 11:05*pm, b4soaring wrote:
On Friday, 25 May 2012 03:54:00 UTC+1, son_of_flubber *wrote: Also, CG hooks can back release if you get a lot of slack in the rope. The manual may suggest a method for blocking the back release - make sure you remove it before winching. If the CG hook is functioning properly (i.e. no weak springs), it would take a LOT of slack to get a back release. So much so that you'd be in front of the tug and probably want to release anyway. Don't mess with the hook or you might make it malfunction completely. Uncommanded releases are not a problem. |
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