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Old Jan 29, 2013, 09:06 AM
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Fms ask23

Other than my RZ Radian, this is my first glider. I briefly had the FMS Fox, but sold it to a friend because it seemed beyond my abilities. Now I'm determined to fly a glider and would like some input on necessary mods, techniques, etc. I have added an additional 18" strip in each wing for a bit more stiffness plus changed all the foam hinges to CA hinging. I have several years experience with planes...just no gliders. Thanks in advance.
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Old Feb 12, 2013, 06:15 PM
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It looks very much like the ASW28 from BH and people seem to really like that sailplane. The spec are about the same as the ASW28, BH says the ASK23 is 50mm longer. I also have years of fixed and rotary wing stick time under my belt. I just ordered one so if you haven't gotten one yet I will update you after it arrives. It seems the major complaint is tip stalling when too much elevator is applied. Kind'a like a Super Chipmunk. We will see in a week or two...
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Old Feb 22, 2013, 08:08 AM
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ok. I put it together in less than an hour. Including seperating servo leads for the ailerons and cutting out a space for the ESC. I have been flying nitro and electric birds for years and I gotta say this is different. I now have to practice using the rudder as apposed to bank and yank... I only flew a couple of times and had to make several approaches on each attempt to land because I was not used to the glide slope. It really did not do anything unexpected and actually had pretty stable flight charistics. Over all I like it... Here is the maiden from the top of the canopy with a #18 keyring camera.
ASK23 Maiden Flight wlmp (9 min 13 sec)
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Old Feb 23, 2013, 08:32 AM
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Thanks for the reply, LH. Nice vid too. I haven't flown it since I posted this thread because of the experience my friend had when he flew my ASK and it tip stalled and crashed. I consider him a pretty good pilot and he said "There's something wrong with this thing!". In the back of my mind, though, I just know there's nothing wrong with it...it is learning how to fly it,which I am really researching. Your comment about too much elevator is very interesting. Could you expand on that? It's driving me crazy just looking at this thing hanging on my wall and I want to get it out, but don't want to mess it up because I don't understand quirks of a long, narrow winged glider.
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Old Feb 23, 2013, 12:13 PM
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I will try to explain it. I am sure someone out here has a better explanation so anyone feel free to help .

Those long narrow wings will stall quickly once the angle of attack is too great. By pulling hard on the elevator the nose gets pointed up too far (unless it is being pulled by the motor) there is not enough air flowing over the top and bottom of the wing to create lift and the wing will 'stall' and the sailplane will fall over to one side or the other. Here is an article http://www.trabucorcflyers.com/uploads/Stall_basics.pdf

If you fly planes you will be just fine. My suggestion is to take it off and get up a high and shut the motor off. It will glide. When it get low power back up and get up high again and shut the motor off again. Don't try to slow it down just learn the glide slope, that way when you land you will already know how it will respond.

I think the weather will be good tomorrow so I think I will get back out and fly it again. I think I will put the camera on it again.
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Old Feb 23, 2013, 01:02 PM
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Guys I also was looking at this glider. I had the radian pro and didn't really like it that much cause I felt like the ailerons weren't to effective but on the BH video the ASK seems to fly different and would be more fun. As far as tip stalling the radian pro was bad for that but I thought all gliders were bad for tip stalling to a point. What are you guys overall impression of it??? Or even better compared to a radian pro???
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Old Feb 23, 2013, 02:08 PM
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Hi, guys. I don't have an ASK23 but I can offer a bit of experience with scale sailplanes in general. Pretty much any scale glider needs more care than a purpose designed glider. I trim scale gliders so that the nose will drop to it's best angle of attack for optimizing lift to drag when I release the sticks and then pull the nose up a bit as conditions demand. One also needs to find the optimum CG. Moving the CG on a scale glider even a millimeter or two can make a drastic change in it's handling.

The very high aspect ratio makes them more prone to dropping a wing in turns and/or a true tip stall where the wing will drop even if you are flying straight and level. The remedies are to fly a bit faster than one might think is necessary, aileron differential (with more travel up than down) and learning to coordinate turns with the rudder. I'm not a big fan of mixing rudder and ailerons but some guys do. It has become second nature for me to use the rudder in turns to the point that I have to break the habit when I go back to a stunt plane and want to yank and bank.

Flying faster, though it might be a bit counter intuitive, allows the plane to fly at it's best lift to drag ratio so, even if it seems like the rate of sink is higher, one is covering much more ground which really helps moving from one thermal to another or penetrating into the wind. Think of your flights in terms of distance covered rather than duration. I have also found that it's best not to try and "core" thermals unless they are really large and allow a wider, faster turn. I'll attach my very crude drawing of the egg-shaped flight path that I use with scale gliders under most conditions. With practice one will find that the turn inside the thermal is almost a chandelle or a wingover. One pulls the nose up to slow down and maximize the time in the thermal but then allows the nose to drop as one initiates the turn. In really light lift or when working very small thermals I don't even try and reverse my flight path while inside the thermal. I just pull the nose up to maximize the lift and then go back to my best glide angle when I hit the edge and move on to the next bubble or make a very wide turn back.

Of course, it will take some trial and error at altitude to get a feel for where the plane wants to depart level flight. For landing approaches I almost always use a little "spoileron". Raising the ailerons effectively adds washout for the critical time when close to the ground. I use the 3-position switch for angles of 10 and 45 degrees on my ASW28. One could also use a knob or slider depending on one's radio and how you like to assign the channels. I don't use the full deflection until I'm on final approach and I'm certain that I won't have to do any more turning.

I think that about covers it. Feel free to ask if I didn't explain myself well. I think you will find that any scale sailplane can give very good soaring performance once one learns their quirks.

Cheers!
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Old Feb 23, 2013, 04:33 PM
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@NCflyer- Personally I like it. This is my only sailplane so I can not answer your question about the Radian.

@Peter - I knew someone could explain it. Thanks!!!
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Old Feb 23, 2013, 06:47 PM
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You're welcome, Low Hover. Always happy to help (Or, at least, try to help.) Scale sailplanes can be a bit intimidating but, once one knows their strengths and limitations, they are very rewarding. Plus they look fantastic whistling by in a low pass or doing lazy aerobatics!
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Old Feb 25, 2013, 11:58 AM
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Went ahead and pulled the trigger on this bird. Hope it flys as well as it looks. I got the ARF so at least it wasn't that expensive in case I don't like it. As with all FMS planes they dont list control throws so what throws are you guys using???
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Old Feb 25, 2013, 05:34 PM
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I am using a JR and just about left everything on 100% with the exception of the down elevator where I had to bring it down some because it was too much throw. I also painted my wing tips and rudder orange (these old eyes just don't see like they used to).
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Old Feb 25, 2013, 07:44 PM
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I also have about 25% expo in all the throws.
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Old Feb 25, 2013, 08:15 PM
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Thanks for the info. I hope it fly's better than the radian pro. The ailerons felt totally
ineffective and the turns were almost all rudder. I dont expect to do hard banking turns but do hope I can at least turn using the ailerons
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Old Feb 25, 2013, 09:50 PM
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Hi, ncflyer79.

I don't have the ASK23, it is on my wish list, but I think you will find that adding some differential throw on the ailerons will help a lot with any glider that has a high aspect ratio. It's just the nature of scale sailplanes. I use servo position to add in the differential and I'll post some pictures tomorrow when I have good light because it's much harder to describe than it is to implement. Every scale sailplane I've owned needs substantially more up aileron than down.

I actually use "negative expo" on the ailerons on all my gliders. They move a lot near the center. I want positive control with just a touch on the stick.
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Old Feb 26, 2013, 08:24 AM
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I have only flown this a couple of times but...... I don't think hard banking turns are something you want to do unless you are close to full power.

Differential on the ailerons is a good ideal to reduce drag. I will add that to mine. I have never thought about negative expo on alierons. I have been flying powered planes(nitro and edf's) for so long that I need to find out the 'tricks of the trade' for sailplanes. I like the principle of negative expo for ailerons but.... that's another thing I would have to slowly experiment with to see if it works for me. Different strokes for different folks
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