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157" Discus Glider

Old 01-29-2009, 10:36 AM
  #451  
A10FLYR
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Default RE: 157" Discus Glider

Sorry Mate, no one had a video camera in hand for the maiden
Old 02-05-2009, 02:18 PM
  #452  
bladerunner1
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Default RE: 157" Discus Glider

Hi
Can you tell me which way up the elevator is supposed to be attatched to the hinge?is it flat side upwards?
Old 02-05-2009, 04:31 PM
  #453  
iflytailies
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Default RE: 157" Discus Glider

flat side of the elevator should be on the bottom
Old 02-06-2009, 09:52 AM
  #454  
bladerunner1
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Default RE: 157" Discus Glider

Ok then joedoe,flatside down.But flyfalcons says flatside up![sm=confused.gif][sm=confused.gif]
Old 02-07-2009, 02:00 AM
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Default RE: 157" Discus Glider

Technically it should be. On this model, however it mounts better is the way to go. I thought mine was symmetrical; I'll have to check it when I get home.
Old 02-07-2009, 03:44 AM
  #456  
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Default RE: 157" Discus Glider


ORIGINAL: Flyfalcons

Technically it should be.
If the stab is NOT symmetrical it will generate lift if the flat part is on the bottom.

If the stab is turned the flat part on top it will generate negative lift, which I'm pretty sure you wouldn't want.
Old 02-07-2009, 04:50 AM
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Default RE: 157" Discus Glider

That's actually what a horizontal stab is for - to generate negative lift. The reason for this is because for a plane to be longitudinally stable, the CG is in front of the center of pressure (lift) on the main wing. Because of that, the plane has a natural nose-down tendancy. To counter that tendancy, a horizontal stabilizer is placed at the rear of the aircraft, providing downforce for level flight. Alternatively, a canard may be installed in the front of the aircraft, providing positive lift.
Old 02-07-2009, 05:46 AM
  #458  
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Default RE: 157" Discus Glider

I thought the lift in the HS is there to counter the "variable wing lift" - as the speed increases the lift increases- thus the plane pitching up tendency with faster speeds. If the stab has (proportional) lift also it keeps the plane in "neutral" position in any speed.

I am not sure this plane was designed this way, but some are.

P.S. not to confuse negative pitch & negative lift

Old 02-07-2009, 01:30 PM
  #459  
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Default RE: 157" Discus Glider

The reason a stable plane wants to pitch up when speed increases is because the horiztonal stab is producing more downforce, raising the nose until the plane reaches its trimmed speed. If you have a plane that is balanced very tail heavy (like my Edge), when you slow down on landing, the tail will start dropping on its own. This is because the horiztonal stab is actually producing positive lift in flight, and is losing effectiveness (and lift) at the lower speed. In a sailplane this tendancy is not desirable because you want your plane to maintain its trimmed speed. Otherwise it will be pitch divergent; push the nose down a little and it keeps going further and further down, increasing speed. You want to be able to push the nose down and have the plane pitch up as its speed increases.
Old 02-08-2009, 03:49 AM
  #460  
bladerunner1
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Default RE: 157" Discus Glider

Thanx for all your inputs.So who's right??I wanna screw the thing on today!!
Old 02-08-2009, 11:59 AM
  #461  
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Default RE: 157" Discus Glider


ORIGINAL: bladerunner1

Thanx for all your inputs.So who's right??I wanna screw the thing on today!!
Blade, all I can show you is I was right about the negative incidence (pitch)- NOT negative lift...

you be the judge
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Old 02-09-2009, 12:55 PM
  #462  
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Default RE: 157" Discus Glider

If the stab has negative incidence, it's going to have downforce. A very thin flat bottom airfoil shape won't overcome a couple degrees of negative incidence. In either case, that vertical stab is different from my 157" Discus. Mine is an all-flying stabiliator, so you guys might be talking about a different glider anyway.
Old 04-28-2009, 01:20 PM
  #463  
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Default RE: 157" Discus Glider

Hi guys!
Been a wile not been connected....I just brought 2 kits of CMP Discus EP and DG-1000 EP...
Before I start building, as I want to electrify them, does any one as some experience of E-Power used ?
As I am living in flat country as Belgium, I would like to have some good climb.....
Thanks for the advise...

Cool flight....
Old 08-11-2009, 03:55 PM
  #464  
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Default RE: 157

Thank you all for the wonderful posting on this sailplane. I had a two meter thermal sailplane when I first started in RC back around 1980 that I flew in the flatland off a highstart. I had to get out of the hobby for about 15 years for "Life Happens" reasons, and have since moved to the Golden Coast of Michigan. I have been flying nitro and electric power again for three years now, and the 140 foot bluff overlooking Lake Michigan a mile away is starting to becon me.[8D] As I love Scale aircraft most, (I have a 6 foot Beaver on floats, and a Parkzone Spitfire) I am looking at Discus and ASW-27/28 in the 2.5-4m spans for scale slope soaring. Any comments would be welcome.
Old 10-27-2009, 12:29 AM
  #465  
erwin peters
 
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Default RE: 157

Hi there, any sugestions where I can buy this sailplane?

regards

Erwin Peters
Old 04-11-2010, 03:05 PM
  #466  
bladerunner1
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Default RE: 157

Maidened the Discus today and..... wow what a flyer i looks just like the real thing!! she flies inverted well and does nice rolls to boot!.
[8D]
Old 05-09-2010, 03:29 PM
  #467  
markfdmodelplanes
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Default RE: 157

well just maiden this 4 m beast .And get this on a hi start. What a fantastic plane i dident even test throw the thing first.The tow hook was set at 1/2 inch in front of c g And befor you ask the c g was set at 80 mm with 1 lb 2 oz of lead but did need a fair bit of up elevator so some of that lead can come out hope to get some video of all this soon what a ***** cat. well happy
Old 05-10-2010, 10:23 PM
  #468  
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Default RE: 157

On a high start, you say? Details man, we need details... rubber ID/OD, rubber and twine lengths, wind conditions, etc. I have one of these planes in the mail, and I am very interested in launching with a high start myself.
Old 05-12-2010, 12:26 AM
  #469  
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Default RE: 157

Well better late than never. I bought the ARF about 2 years ago and finally got around to building it last month. Used an Aeronaut 14X12 folder, HeadsupRC 4248-08 (http://www.headsuprc.com/servlet/the...tor/Categories) motor, a 100 amp ECS, a pair of 4S2300 A123 packs wired up in parallel made up from a Dewalt pack, standard hitec servos except I added HS225's in the tail for the rudder and elevator. JR 9 channel 2.4 ghz receiver. Did the recommended strengthing of the fuse floor. The motor prop combo pulls 540 Watts. Also 13 oz of #8 shot in a bag as added to get the CG right. Set the tail and wing incidence to 0/0. CG under the wing rod.

Maiden was in 12-14 mph winds at the soon to be closed Bonsall Field, my buddy M-B James threw it out for me and it flies like a big trainer. Climb out was 30-40 degrees it took about 10 seconds to start downwind where I shut the motor down, then flew a left hand pattern till over the field and repeated about 5 times. The wings flapped around like they were maid of rubber.

The only problem is on landing, I threw in the spoilers and landed short of the field into a dirt berm Caltrans dug. I'm throwing the blame to the plane cause it looked alot closer than it was.

The rudder hinges pulled out, the right wing root pulled out of the wing sheeting and there is a small crack on the left fuse where the wing rod fits though.

Easy fixes and now that I see there is nothing behind the wing root ply I'm gonna open up both wings and reinforce them with lots of balsa.

I setup the spoilers, ailerons and elevator on the left stick ala Crow. I ended up having +3 Elevator (that up elevator). Hope that helps someone cause all my other gliders with Crow has down elevator trim.

Its worth $150 just to see this thing fly with the wings flapping in the turbulence. Can't wait to fly it on a calmer day. I put in 1620 mah (810 mah each pack) so I could have flown a dozen climbs.
Old 05-13-2010, 03:03 PM
  #470  
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Default RE: 157

well put a few more launches on the hi start . Very stable and pedictable. the only things is not much wind in England at the moment and the planes not flying the full length of the 300 ft line, so just trimming flights really with a couple of circuits. As for high start set up I bought surgical tubing off the internet adverstised as capable of launching up to 5 kg models (from e-bay) 10 metres of and extended with 50lb fishing line. I have watched a 4metre ash on youtube being launched which put me right off high starts! But this discuss is very normal and predictable, I launch it myself.
So have no worries just go and buy and enjoy! And slope soaring is next! I'll keep you posted
Old 05-15-2010, 07:09 AM
  #471  
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Default RE: 157

WRT that ASH-26 high start launch on YouTube, gotta say... NICE recovery! I'm thinkin' the throws (launches) were ummm.... less than perfect.

Meanwhile, do you know what your 4M ended up weighing, exactly? Also, what did you use for servos?
Old 05-16-2010, 02:51 PM
  #472  
markfdmodelplanes
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Default RE: 157

well got the longest flight today off the hi start 10 mins .Still not getting the full lenght out of the line winds were 10 to 20 mph a bit more practice with me launching it and getting up elevator on .As for set up hitec hs 125 servos in the wings and mini servos on the air brakes and standard servos for rudder elevator.I did bring the elevator servo along side the rudder servo to keep the weight down in the tail .I also have taken some lead out so there is less than 1 lb of lead now and feels more like a glider and less like a guided missile
Old 06-01-2010, 04:47 PM
  #473  
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Default RE: 157

I'm new to 4 m gliders. Been flying scale war birds for a long time and then 3D models and then! and then ! I whent back to where i started back to gliders 20 years later But i didn't notice or i just had not looked how far gliders had gone . I can't believe the speed records ! the endurability the strenght.The scale. Slope soaring. Air towing.Hi starts. trying to find a thermal to extend the flight. knowing that this is the one and only chance to land! And then some one at the local club said to me "why dont you but an engine in it" AHHHHHHHHHHHHHHHHH
Old 09-29-2010, 10:08 AM
  #474  
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Default RE: 157

subscribed!
Old 03-06-2011, 06:56 PM
  #475  
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Default RE: 157

Where can I buy one of these ?

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