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Old Sep 28, 2012, 01:39 PM
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He did not know the name but the receiver was very small, about the size of a cell phone an looked home made, very low frequency, transmitter was postage stamp size with button battery, looked hot glued on. He was talking much lower price.

And yes the beepers have their place, I use them on foamies we fly over a large field of 3 ft high grass, it makes it easy to find them if they drop, even far away, you know the general area because you see them go in, so when you get there you can hear them, but only again if battery stays connected! Just don't think they are good enough for gliders.
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Old Sep 28, 2012, 03:50 PM
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Originally Posted by kaptondave View Post
I don't know what you mean by "20 knot climb speed". Flying directly into a 20 knot wind with an airspeed of 20 knots the plane would remain stationary with respect to the ground but would not necessarily be going straight up. It could be gaining or losing altitude, or neither, depending on angle of attack.
Well if the plane is climbing, and not moving forward because its speed has been adjusted for no forward movement, then how else would it be climbing if not straight up?

The fellow who I was quoting originally implied that Rate of Climb was a distance measurement. I replied that, no, rate of climb is measured in FPM. He then said that there were other rate of climb measurements, something I'd never heard before, and said further that glider pilots have a rate of climb incorporating a distance measure. So I gave the illustration that I did which was correct in the context of our discussion.

In any case in my example I stated that the plane was going into the wind at a speed with no forward movement AND climbing, So yes, if the plane is not moving forward and it is climbing it has to be climbing straight up from the standpoint of a ground observer.
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Old Sep 28, 2012, 04:17 PM
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kaptondave and cliffkot,

I think you are talking about the same things, using different terms from each other and from what is typically used by full scale aviation pilots. (CAVEAT, I am NOT a full scale pilot, though have studied it a fair bit as a hobby.) There are two measures of climb rate on take off for pilots. In any particular aircraft there is Vy and Vx. Vy is the best rate of climb where as Vx is Best ANGLE of climb.

Remember in full scale flying the plane has a set take off power, so the amount of thrust is the same regardless. What changes is the ANGLE of climb out. You trim the angle to achieve a stable indicated airspeed. (Not above ground speed, where wind IS a factor) If you want to gain altitude in the most efficient manner, and obstacles are NOT an issue, each aircraft's Vy will allow it to gain altitude as efficiently as possible.

IF however there are obsticles that must be CLIMBED OVER before you go a certain distance, you then trim for Vx, or Best Angle of Climb. You will be moving more slowly, and therefore covering ground less quickly, while you are climbing more steeply. In the end, over time, you are not gaining the altitude as EFFICIENTLY, but you get higher over a shorter distance, in order to get over the obsticles.

I suspect the term "best rate of climb/distance" that was being used probably would equate to Vx ...

To try to bring this back on topic, I know that I can go up quite steeply with the RP when WOT on launch, so it does not get very FAR from me horizontally while it is climbing out vertically. That would be a launch at Vx. I do, however, find that it actually tends to gain altitude MORE EFFICIENTLY if I shallow out the angle and keep the speed up and just do gentle turns while climbing, to keep it close. That would be a Vy climb out. Both have their purposes in aviation.

Wind, on the other hand, simply affects GROUND SPEED, not indicated speed. Your pitot tube would still indicate 20 km/hr into or with a 10 km/hr wind, but your ground speed would be either 10km/hr or 30 km/hr. NEITHER changes the Vx or Vy, which is dependant upon indicated airspeed, or the speed of the air across the lifting surfaces.

Not sure if this has helped or hindered, but it's always entertaining.

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Old Sep 28, 2012, 04:47 PM
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Originally Posted by Fish99 View Post
kaptondave and cliffkot,

I think you are talking about the same things, using different terms from each other and from what is typically used by full scale aviation pilots. (CAVEAT, I am NOT a full scale pilot, though have studied it a fair bit as a hobby.) There are two measures of climb rate on take off for pilots. In any particular aircraft there is Vy and Vx. Vy is the best rate of climb where as Vx is Best ANGLE of climb.

Remember in full scale flying the plane has a set take off power, so the amount of thrust is the same regardless. What changes is the ANGLE of climb out. You trim the angle to achieve a stable indicated airspeed. (Not above ground speed, where wind IS a factor) If you want to gain altitude in the most efficient manner, and obstacles are NOT an issue, each aircraft's Vy will allow it to gain altitude as efficiently as possible.

IF however there are obsticles that must be CLIMBED OVER before you go a certain distance, you then trim for Vx, or Best Angle of Climb. You will be moving more slowly, and therefore covering ground less quickly, while you are climbing more steeply. In the end, over time, you are not gaining the altitude as EFFICIENTLY, but you get higher over a shorter distance, in order to get over the obsticles.

I suspect the term "best rate of climb/distance" that was being used probably would equate to Vx ...

To try to bring this back on topic, I know that I can go up quite steeply with the RP when WOT on launch, so it does not get very FAR from me horizontally while it is climbing out vertically. That would be a launch at Vx. I do, however, find that it actually tends to gain altitude MORE EFFICIENTLY if I shallow out the angle and keep the speed up and just do gentle turns while climbing, to keep it close. That would be a Vy climb out. Both have their purposes in aviation.

Wind, on the other hand, simply affects GROUND SPEED, not indicated speed. Your pitot tube would still indicate 20 km/hr into or with a 10 km/hr wind, but your ground speed would be either 10km/hr or 30 km/hr. NEITHER changes the Vx or Vy, which is dependant upon indicated airspeed, or the speed of the air across the lifting surfaces.

Not sure if this has helped or hindered, but it's always entertaining.

Well I wasn't talking about that. I am a pilot and quite familiar with those speeds. The original poster was talking about best climb over distance covered, something I'd never heard before, not best climb over obstacle.

I indicated that such a measure would have to incorporate wind speed because the best climb in a given distance would be ANY climb without forward movement. In fact such a performance measure would have an infinite value, regardless of how fast you were moving upward, which suggests to me that such a measure doesn't really exist and that I was correct when I asserted that rate of climb is measured in FPM. But I try to keep an open mind so I gave it some thought. I just don't see how that kind of measure would exist.

This is an interesting problem. Vx is a measure of best angle of climb, and has to do with thrust available for climb vs. the energy required for forward movement. But if we observe from the ground (or are concerned about flying into a box canyon) we could use wind to our advantage if it was available, by adjusting power and angle of attack so that we climb but don't move forward. That way we go up like an elevator, clear the canyon, and then resume our merry way. Interesting idea, just never thought of it before the fellow posted it.

I'm not talking about wind affecting the performance of the aircraft. Everyone who has flown a glider in a stiff wind has hovered at some point (or even look ma, I'm going backwards), But if you added power when in that condition, and pulled up to keep your forward speed the same, you'd climb without moving forward over the ground. In a box canyon, you'd save everybody and be the hero. Of course I've never heard of a stiff breeze blowing from the closed end of a box canyon, but who knows.

If Vx means least forward distance through the air, with max altitude gained, then any headwind would be to your advantage and improve the situation because naturally you'd be covering less ground. By implication minimum distance through the air would be related to minimum distance over the ground but that distance covered would of course be proportional to wind. The problem is in how it is stated and it seems to me that the dictionary definition has something assumed (understood) in its the statement.
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Old Sep 28, 2012, 06:15 PM
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Mystery solved. I found the answer. All the performance graphs I've been able to find that involve some distance over ground measurement are predicated on zero wind. It is written right on the graph in bold type and plain English. I just never noticed it before.

So any performance measure that is based on ground reference must consider wind and the actual performance will vary with the wind. That is obvious of course, but when you only consider how the spec is stated, the implied wind component isn't so obvious because it isn't necessarily implied in the name.

So you climb at a certain airspeed and you are guaranteed to clear the trees at some distance, but if you have a head wind you will naturally exceed the guaranteed clearance.
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Old Sep 28, 2012, 07:07 PM
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Quote:
Originally Posted by Fish99 View Post
kaptondave and cliffkot,

... In any particular aircraft there is Vy and Vx. Vy is the best rate of climb where as Vx is Best ANGLE of climb.....

Wind, on the other hand, simply affects GROUND SPEED, not indicated speed. Your pitot tube would still indicate 20 km/hr into or with a 10 km/hr wind, but your ground speed would be either 10km/hr or 30 km/hr. NEITHER changes the Vx or Vy, which is dependant upon indicated airspeed, or the speed of the air across the lifting surfaces......
+1..well stated.
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Old Sep 28, 2012, 07:55 PM
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Absolutely correct, but the discussion was about the distance over ground covered for altitude gained being a performance expressed as a rate. I had never heard of this expressed as a rate. That is what I was trying to figure out. And I don't think that this is an actual rate measure. At least I haven't found it expressed that way in any literature.
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Old Sep 28, 2012, 10:09 PM
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http://expertaviator.com/2011/02/03/...rate-of-climb/
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Old Sep 28, 2012, 10:52 PM
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Originally Posted by Gerry__ View Post
No. As cuff said, rate of climb is measured in feet per minute. You are confusing rate of climb with angle of climb.
The aeronautical term is gradient, but it is indeed a rate of climb over distance.

It appears (based on your blog) that you enjoy proving folks wrong, but it would be nice if you would not try to embarrass a fellow who is new here and who has just smashed his plane into the ground. He obviously did not know to chop his throttle.
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Old Sep 29, 2012, 12:15 AM
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Originally Posted by JumpySticks View Post
All that flight planning stuff boils down to rate of climb in feet per minute. This argument is about correct terminology. You didn't use correct terminology, and that's what I picked you up on.
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Old Sep 29, 2012, 12:22 AM
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Quote:
Originally Posted by kaptondave View Post
Terminology is confusing enough without people inventing new ones, but "rate" is the ratio of any parameter to any other parameter. Rate of climb can be expressed as feet per minute or feet per mile.
Agreed, but it's the mashing up of terminology to produce something non standard that I don't like.
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Old Sep 29, 2012, 06:56 AM
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Dsx9

I am new to sailplanes (well 6 servo ones anyway) well hopeing someone will be able to give me some tips on setting the Radian pro up on the JR Dsx9 I have it set on Acro and have it all working inc flaps but no other mixs, when I put it on the sailplane setting I couldnt even get the motor to run, maybe the RX channels are not the same?.
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Old Sep 29, 2012, 09:01 AM
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Originally Posted by Gerry__ View Post
Agreed, but it's the mashing up of terminology to produce something non standard that I don't like.
If you visit threads where not everyone is an expert (radian pro is not a professional plane) you can expect to see a lot of language that is not up to your standard of perfection. There is no reason to make beginners feel like they don't belong or are not welcome.
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Old Sep 29, 2012, 09:14 AM
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Originally Posted by JumpySticks View Post
If you visit threads where not everyone is an expert (radian pro is not a professional plane) you can expect to see a lot of language that is not up to your standard of perfection. There is no reason to make beginners feel like they don't belong or are not welcome.
I've not done that. Stop with the personal attacks already!
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Old Sep 29, 2012, 12:28 PM
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Relax guys!

(I'm on the east coast and your rocks are falling short in both directions!)
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