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Old Jan 20, 2013, 06:59 AM
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Siggy101's Avatar
Switzerland, VD, Chéserex
Joined Jan 2011
246 Posts
Question
Hook position on Sloper

I have been flying my NAN Models Alex XXL (also known as Spider XXL and Speed XXL to you guys across the pond) 2.6m for a year or so and all is well however when building it, it did not put in the tow hook as I didn't expect to use it.
Well, I have come to realise that the wind does not always blow strong enough here in Switzerland to keep her aloft so I am now looking at a little up-start / hi-start / zoom / bungee type thing to get me some speed/altitude. I am just talking about a setup that pulls the glider forwards and I then come off the end and pull up giving me the desired speed / altitude boost. This would be on the slope for a change to hand launching and on the flat to just get flying time and practice.
The hook was included in the kit and looks to be a pretty substantial bit of kit.

My question is simply where to put the hook.

I am not looking for the traditional 'just forward of the cg' position that people would use for winch launching to gain maximum altitude but instead is it ok to position it as per the photos? I really don't have any other options as I have kind of painted myself into a corner with the build. I had a look at positioning it up in front of the servo tray however I can't then get the battery in again.

Is this position likely to be stable enough in pitch or am I too far aft? I would ideally put it way up front but that's no longer an option...

If anyone happens to have the same model and uses a bungee to start on the slope, I would be really grateful of a few photos.

Many thanks guys!
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Old Jan 20, 2013, 08:44 AM
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mdennis's Avatar
Shawnee, Kansas
Joined Nov 2002
1,138 Posts
If there is a slot back by the CG where it would normally go, I would put it there. Then just position the hook all the way to the front of the slot.

Your bungee will still pull it pretty flat, but if you ever want to sell this plane in the future, you will have a much bigger group of people who will wish to buy it because they won't have to patch it when they move the hook back to where it goes for a winch launch.

Just my opinion
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Old Jan 20, 2013, 09:52 AM
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Siggy101's Avatar
Switzerland, VD, Chéserex
Joined Jan 2011
246 Posts
Quote:
Originally Posted by mdennis View Post
If there is a slot back by the CG where it would normally go, I would put it there. Then just position the hook all the way to the front of the slot.

Your bungee will still pull it pretty flat, but if you ever want to sell this plane in the future, you will have a much bigger group of people who will wish to buy it because they won't have to patch it when they move the hook back to where it goes for a winch launch.

Just my opinion
There is no slot anywhere as yet. It did not come with any holes anywhere.
I can't imagine anyone wanting to winch launch this as it is a slope sailplane as far as I know. It is a bit heavy for TD.

By the sounds of what you are saying, if the furthest forward position in a winch launch slot would work fine then my proposed location is further forward still so should be alright...
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Old Jan 20, 2013, 10:13 AM
Registered User
Joensuu, Finland
Joined Mar 2002
1,531 Posts
Yes, for your intended use it will be fine. But if you wanted to winch it on flat land, you might run out of elevator before reaching an efficient climb angle. In other words, with a forward hook position, it will launch more horizontally rather than climb.
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Old Jan 20, 2013, 11:12 AM
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Siggy101's Avatar
Switzerland, VD, Chéserex
Joined Jan 2011
246 Posts
Thanks Jkettu, that is just the info I was after.
I don't have access to a winch nor am I likely to in the future so I think I should be safe to attack her with the Dremel.
Do I just draw out the marks from the outside and get drilling or is there a different way I should do this? Any epoxy needed on the inside or are the screws enough to hold everything tight?
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Last edited by Siggy101; Jan 24, 2013 at 08:30 AM.
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Old Jan 20, 2013, 01:53 PM
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BigSwede's Avatar
United States, CA, Thousand Oaks
Joined Feb 2007
1,771 Posts
Here's what I would do. Put the hook in the standard high start position near the CG. Why? Just because, haha! That's where it belongs. This thread tells you a lot of info;

http://www.rcgroups.com/forums/showt...zip+start+hook

Use a piece of music wire to make a tape on hook extension;



Now you can adjust the length of your wire to get the hook wherever you want, and you can still have a "standard" winch hook. Just my two cents.
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Old Jan 24, 2013, 08:45 AM
No risk, no fun
Siggy101's Avatar
Switzerland, VD, Chéserex
Joined Jan 2011
246 Posts
Thanks for all the pointers guys.
That link was really helpful Swede and it has lead me out to the German forums where people talk about 'Flitschenstart'. That is exactly what I am trying to achieve so I have been on a mission yesterday and got the parts needed and have now manufactured a little threaded rod and tube system that allows me to have a small 'straight hook/pin' sticking out that can then be wound back inside when not needed. Seems perfect for my needs!

Let's hope I can brace it sufficiently so that it stays put. It looks like some serious energy can be harnessed in that rubber tubing! I feel a bit of carbon tow and epoxy is in order!!
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Old Jan 24, 2013, 10:52 AM
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satinet's Avatar
Warwickshire, England
Joined Sep 2006
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I would put the centre of the hook slot on the CG. That way you can go forwards or back from there to get a good launch.

Good winch launches don't have forward hook positions.
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Old Jan 24, 2013, 12:29 PM
No risk, no fun
Siggy101's Avatar
Switzerland, VD, Chéserex
Joined Jan 2011
246 Posts
Quote:
Originally Posted by satinet View Post
I would put the centre of the hook slot on the CG. That way you can go forwards or back from there to get a good launch.

Good winch launches don't have forward hook positions.
I think we are at crossed purposes here.
This is for a slope soaring glider and I am not using a winch. I am not after altitude by virtue of a winch and lift from the steep angle of attack but instead using rubber tubing to give me horizontal velocity followed by a steep climb once detached.

Thanks for the hint on the winch launch though. An entirely valid point for that sort of launch.
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Old Jan 24, 2013, 12:32 PM
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perttime's Avatar
Tampere, Finland
Joined Nov 2004
4,343 Posts
If it is for Slope, I'd ask the question in the Slope forum. There's people there who do bungee launches: horizontal for speed, not high-starts for altitude.
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Old Jan 24, 2013, 01:13 PM
cq cq de kr4is
flexsphincter's Avatar
USA, VA, virginia beach
Joined Jan 2011
277 Posts
When we slope virginia beach ocean front high rise hotels while standing on boardwalk we use short bongy 20 ft long tied to railing. Hook lil forward of cg. This makes plane gain suffient speed and wants to naturally achieve a lil up alfa
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Old Jan 25, 2013, 11:37 AM
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Evan D's Avatar
Charlotte, NC
Joined Jan 2004
6,184 Posts
From my past experience where yo have it is a tad forward of where I would put it. I'd go about two inches (50mm) further back. I think it will only go straight out flat where you have it now and you want some up.
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