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Old Jul 09, 2012, 05:16 PM
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Thanks Harm, great tips. Did you cut off the nose of the K8 to install the tow release? Did you tie the nose into the rest of the fuse with more reinforcements?

Regarding strengthening the vertical fuselage ribs, did you make up doublers for them, more bracing, etc.?

Steve
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Old Jul 09, 2012, 06:28 PM
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FEMA or Robbe wheel

Anyone know where to purchase a FEMA or Robbe wheel, preferably in the US? (110-112mm seems about right.) I doubt the larger Dave Brown or Dubro foam ones are stout enough. Thanks. Bob
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Old Jul 09, 2012, 06:45 PM
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Quote:
Originally Posted by flyingfever View Post
Anyone know where to purchase a FEMA or Robbe wheel, preferably in the US? (110-112mm seems about right.) I doubt the larger Dave Brown or Dubro foam ones are stout enough. Thanks. Bob
Try the big sullivan with the alloy hub, having said that my alloy one that came with the model is already 150+ flights old now and working well.
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Old Jul 09, 2012, 06:58 PM
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I have two 150mm FEMA in stock. Please send PM if interested
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Old Jul 09, 2012, 07:07 PM
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One thing that I am adding tonight. Olythom thought of it. We are putting the clear mylar used by rc car guys to protect the bottom of their chassis on the skid areas. This is very tough stuff.


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Old Jul 09, 2012, 07:58 PM
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Originally Posted by iflytailies View Post
I have two 150mm FEMA in stock. Please send PM if interested
Thanks. The 112-114 mm ones (4.5 ") are close to scale, and just fit with a little clearance. The 150mm would require cutting out the supports & opening, and re-building the receiver box. Love the pilot I got from you a while back, tho. Thanks, Bob.
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Old Jul 10, 2012, 12:45 AM
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here is a link to video of our first tows.On first one we learned our tow line was not strong enough. We switched to a stronger line and got several flights in. The second and third flights on the video were the maidens of each of our planes. The tows were short to get the gliders trimmed.
RC Video: Phoenix K8b Glider & Piper Pawnee Tow Plane (4 min 10 sec)


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Old Jul 10, 2012, 06:11 AM
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Great video Mark, If I may make a couple of observations, during your tow you look to be dragging the glider off the deck beofore the glider has reach flying speed, let it rotate buy itself, the model does this really well and helps to stop wind getting under it on a windy day. Lastly I found that with the 10% down elevator mixed into tow release the model sits at a really nice height above the tug and makes it easier for the tug to climb, 1-1/2 models above the tug looks cool and works best for me as well as helping not to stall the tug and makes the tug pilots job much easier to climb. Please don't take my observations the wrong way, just trying to help out so you guys can get as much fun out of your KA combo we have over the past 8 months.

cheers Rossco.
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Old Jul 10, 2012, 09:16 AM
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Rossco, I am open to any advice. We are very new to this. We are letting it take off on it's own, the only control input is keeping the wings level. These things just want to fly. I will try the down elevator mix.

Mark
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Old Jul 10, 2012, 10:31 AM
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No worries Mark as long as your having fun and buy the look of it your doing a good job.
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Old Jul 10, 2012, 05:55 PM
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Anyone understand why planes like the K8 and Minimoa benefit from a bit of down elevator on tow? I ask as I used to struggle with my 4.8 meter Mini. It used to wag from side to side until I tried a little down and now it tracks perfectly. Still don't understand the dynamics.

Steve
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Old Jul 10, 2012, 06:15 PM
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Steve, Wagging on tow is a sign of the plane being tail heavy. Which of course would be helped with the down elevator.

Len
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Old Jul 10, 2012, 06:40 PM
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Sorry... "wagging" was a bad choice of words. It oscillates and at time almost to the point of doing a barrel roll. I would think if it's tail heavy, the plane would still require a bit of down elevator to fly level once off tow, yet the elevator is quite neutral and the plane pulls out of a dive test in a very predictable gentle arch upwards.

The only reason I tried a bit of down on tow was because someone once commented that the plane appeared to be stalling...maybe a high speed stall?

Well, all of this is a bit academic since the plane was destroyed last fall due to a TX failure...the second for that radio which is now confined to the junk heap.

A new Mini will be ready for SKSS. We'll see how it behaves...along with a different radio!

Steve
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Old Jul 10, 2012, 06:53 PM
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hi Steve the closest explination I can come up with is the relation between the tow point, low down relative to the wing up high, kind of like winch launching at higher speed, the other is the higher airspeed in relation to the wing incidence, effectively the model is kiting. I remeber being told the 1-26 schweizer coud be winch launched from the nose hook, not sure if this is true or not but just my thoughts.
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Old Jul 10, 2012, 07:30 PM
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I think airspeed has a lot to do with it as the problem seems to get worse the faster the tow.

And now that I think about it, I had the same experience at JR this year with the 5.6 meter Lanyu Minimoa which was balanced per other pilots' experience but needed down trim on tow.

Well, whatever it is, at least we know how to deal with the situation.
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