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21m tipped Lak 17b!



 
 
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  #21  
Old November 7th 13, 02:14 PM posted to rec.aviation.soaring
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Default 21m tipped Lak 17b!

Yes. You can fly 13.5 as well!
  #22  
Old November 7th 13, 02:16 PM posted to rec.aviation.soaring
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Default 21m tipped Lak 17b!

Good point on the article but the HC committee should be smart enough to figure these obvious things out on their own. It's as if they did not think about or research this glider in any way vs a pure glider.
  #24  
Old November 7th 13, 03:24 PM posted to rec.aviation.soaring
Dan Daly[_2_]
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Default 21m tipped Lak 17b!


According to an article I read (Gliding International I think) you will

not be able to fly 13.5/15/18/21. The 13.5 will have a different

fuselage than the prototype, in order to keep within class limitations.



Luke


Article posted on company website at http://lak.lt/index.php?option=com_c...1&Item id=145.

DD
  #25  
Old November 7th 13, 04:31 PM posted to rec.aviation.soaring
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Default 21m tipped Lak 17b!

On Thursday, November 7, 2013 8:16:56 AM UTC-5, wrote:
Good point on the article but the HC committee should be smart enough to figure these obvious things out on their own. It's as if they did not think about or research this glider in any way vs a pure glider.


Having worked as part of the US handicap subcommittee for many years, I would as the writer where the data for this "obvious" thing would be located? The factory claims minimal loss of performance. I would be inclined to agree. If an owner was to request a review by the HC, and provide basis for requesting it, I'm sure it would be looked at. A rough guess would be it may reduce cross country speed by a tenth of a percent or two. That would make a scoring error of a couple points a day.
UH
  #26  
Old November 7th 13, 05:22 PM posted to rec.aviation.soaring
Sean F (F2)
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Default 21m tipped Lak 17b!

On Thursday, November 7, 2013 10:31:19 AM UTC-5, wrote:
On Thursday, November 7, 2013 8:16:56 AM UTC-5, wrote:

Hank,

I have heard the performance is degraded 1% at low speeds and 2% at high speeds from the factory. I have also heard as much as a 2-4% degradation was found on a recent non factory sponsored test.

The airflow of the Lak17b FES is clearly disturbed at the nose and that turbulence very likely impacts the wing root slightly, more at higher speeds. I would take a bet that claimed only .1% performance impact. I am almost certain that it is much more than that. It just takes a simple look at the system itself to see the disturbance that is created by the root of the propellers when folded, not to speak of the 18 inch propeller blades lying on the fuselage nose when folded back in gliding flight. They have done a wonderful job trying to make it clean, but that folding propeller it is not perfect by any means.

Here is a thought! If the ASG29 had FES as a standard offering I can bet the handicap adjustment would be under more serious consideration!

A handicap adjustment for the Lak17b is absolutely needed in the US. The fact that their IS a performance impact IS NOT DEBATABLE. The only debate is how much.

Here are some photo's that clearly show the structure of the folding propeller system and its impact to the airflow: https://www.google.com/search?q=fron...w=1706&bih=781


Good point on the article but the HC committee should be smart enough to figure these obvious things out on their own. It's as if they did not think about or research this glider in any way vs a pure glider.




Having worked as part of the US handicap subcommittee for many years, I would as the writer where the data for this "obvious" thing would be located? The factory claims minimal loss of performance. I would be inclined to agree. If an owner was to request a review by the HC, and provide basis for requesting it, I'm sure it would be looked at. A rough guess would be it may reduce cross country speed by a tenth of a percent or two. That would make a scoring error of a couple points a day.

UH

  #27  
Old November 7th 13, 06:13 PM posted to rec.aviation.soaring
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Default 21m tipped Lak 17b!

On Thursday, November 7, 2013 11:22:21 AM UTC-5, Sean F (F2) wrote:
On Thursday, November 7, 2013 10:31:19 AM UTC-5, wrote: On Thursday, November 7, 2013 8:16:56 AM UTC-5, wrote: Hank, I have heard the performance is degraded 1% at low speeds and 2% at high speeds from the factory. I have also heard as much as a 2-4% degradation was found on a recent non factory sponsored test. The airflow of the Lak17b FES is clearly disturbed at the nose and that turbulence very likely impacts the wing root slightly, more at higher speeds. I would take a bet that claimed only .1% performance impact. I am almost certain that it is much more than that. It just takes a simple look at the system itself to see the disturbance that is created by the root of the propellers when folded, not to speak of the 18 inch propeller blades lying on the fuselage nose when folded back in gliding flight. They have done a wonderful job trying to make it clean, but that folding propeller it is not perfect by any means. Here is a thought! If the ASG29 had FES as a standard offering I can bet the handicap adjustment would be under more serious consideration! A handicap adjustment for the Lak17b is absolutely needed in the US. The fact that their IS a performance impact IS NOT DEBATABLE. The only debate is how much. Here are some photo's that clearly show the structure of the folding propeller system and its impact to the airflow: https://www.google.com/search?q=fron...w=1706&bih=781 Good point on the article but the HC committee should be smart enough to figure these obvious things out on their own. It's as if they did not think about or research this glider in any way vs a pure glider. Having worked as part of the US handicap subcommittee for many years, I would as the writer where the data for this "obvious" thing would be located? The factory claims minimal loss of performance. I would be inclined to agree. If an owner was to request a review by the HC, and provide basis for requesting it, I'm sure it would be looked at. A rough guess would be it may reduce cross country speed by a tenth of a percent or two. That would make a scoring error of a couple points a day. UH


From the FES web site:
We developed a special very light carbon fibre foldable propeller. The propeller opens quickly using centrifugal force when rotation starts. It has 1.0m in diameter and each blade weighs only 240 grams. The blades are slightly bent to take the shape of the front surface of the fuselage. During propeller folding, pitch of blades is automatically reduced when they rotate closer to the fuselage. Additional drag of the folded propeller is really minimal as proved by accurate Idaflieg flight performance measurements.

Obviously it would be useful for an interested party to provide the Idaflieg data to the handicap committee so that an appropriate adjustment could be made.
That would certainly take my WAG or Sean's "I have heard" info out of the picture. It certainly is a cool approach to the sustainer issue.
UH
  #28  
Old November 7th 13, 06:37 PM posted to rec.aviation.soaring
JS
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Default 21m tipped Lak 17b!

Seems like an interesting multi-span glider.
Without having flown one, have to wonder how the Lak feels compared to the familiar handling of AS or JS.
Too bad it isn't possible to enter 13.5m comps too. The ASG29 and V2Cx could also have 13.5 tips fitted. The ASW17B was fun in 15m, And an inexpensive mod if there ever was one.
Jim
  #29  
Old November 8th 13, 01:17 AM posted to rec.aviation.soaring
Dan Marotta
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Default 21m tipped Lak 17b!

As to handling, I have about 650 hours flying the LS-6a and find the LAK-17a
(about 350 hours, so far) to be every bit as pleasant and responsive to the
controls. It also has a better rudder.


"JS" wrote in message
...
Seems like an interesting multi-span glider.
Without having flown one, have to wonder how the Lak feels compared to the
familiar handling of AS or JS.
Too bad it isn't possible to enter 13.5m comps too. The ASG29 and V2Cx
could also have 13.5 tips fitted. The ASW17B was fun in 15m, And an
inexpensive mod if there ever was one.
Jim


  #30  
Old November 9th 13, 09:09 PM posted to rec.aviation.soaring
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Default 21m tipped Lak 17b!


Here is a thought! If the ASG29 had FES as a standard offering I can bet the handicap adjustment would be under more serious consideration!


Sean, you just have to stop with the unsubstantiated allegations of unethical behavior by the US handicap committee. Have you approached them directly about the FES handicap? Have you provided them any data they can use? Have you been rejected in a request for a handicap adjustment? Or are you just sitting at your computer imagining some big anti-LAK conspiracy by the evil lords of the handicap committee? C'mon, for once be reasonable. It's going to be a long winter.

John Cochrane.
 




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