Petepala1961

What's your highest altitude with an electric glider? I owne the Spectra with 1800mah and stick gold fire motor.

thanks in advance.

pete

Petepala1961

Petepala1961

No one has any idea how high they've own?

hattend

My Feedback: (20)

Electric glider, 100 inch span, specked...occasionally out of sight. Modified Airtronics Aquila, geared Astro .05

Regular glider, 10 foot span, specked in binoculars while I lay back in a lounge chair.

I have no idea how high either of those flights were. Way up there.

Don

1320Fastback

Gone as high as I could see with a Easy Star. Maybe 2000'????

aeajr

My Feedback: (2)

Not really important to me. My goal is flight duration, not altitude. The higher I go the more chance to interfere with full scale aircraft.

Typically, on my 3M gliders I top out around 2000 feet. No real needto go higher than that.

Petepala1961

Thanks guys. I was figuring a couple thousand.

Sometime Im going to sitdown, work out the wingspan apparent width for a given distance then scale out as it'd appear at given distances beyond that point. Its a simple exercise. It'd be interesting to see how it factors out . There's gotta be a point where the speck is visible but situationally unrecognizable. A neat paper exercise anyway.


again my thanks folks!

Pete

aeajr

My Feedback: (2)

Petepala1961

Ha. Look at that!

thanks many!

Pete

da Rock

That theory was used by the military for a couple of wars at least. They even created devices for the observers to use. They tested them and came to the conclusion that the methods weren't anywhere close to reliable enough to bother with the devices. They of course, continued to use the observers but didn't rely upon the altitudes they "measured". They found that experience of the observers with a bit of training was just as valuable.

However, once upon a time, in a land far to the north of here...............

da Rock

Once upon a time, in a land far to the north of here...............

I spent a good number of years in Minnesnowta, land of sod farms and slopes. For quite some of that time, my primary hobby was gliders. Every aspect of model gliding was sampled and savored. Well, almost every. anyway...

While flying thermal gliders up there, it was discovered that some sort of method was needed in order to cut down on the number of lost gliders, lost by flying them out of sight vertically. Even if you're smart enough to realize before doing it, unless you come up with some plan, flying them out of sight happens way too easily. After a couple of losses, and some intense thought.............

The 2-dot rule was devised.

But first.... consider what is required and how impossible it is to do to base your rules on any system that requires knowledge of the model's true altitude. Also remember that we fly models with different planform silhouettes, models with different wingspans, and more importantly different wing chords. For example, 2m's are going to be harder to see than 14' Unlimiteds when they are at the same altitude. So the specific altitude isn't the key. Also, each person's eyesight is of major importance.

So...... now for the 2-dot rule.

Have you noticed what your glider looks like when it's way up there? At some distance from you, the fuselage can no longer be seen. Right about there what do you see? Most would describe what they see as a dash and a dot. The dash of course is the wing while the dot is the horizontal tail. Have you noticed how impossible it is once your pride and joy has become just a couple of dots how hard it is to tell if it's still in lift? That is, unless it's not. When it's not, it's pretty easy to tell because you not only lose the scary feeling but the sucker is getting larger. But when it is in lift..............

You will notice that the dash that's been providing you some comfort has lost some of it's dash. It's now just a darker dot. And the other dot is really a dot.... and a small one at that. And then...........

You realize that you no longer see two dots. That's when the 2-dot rule kicks in. It's time to do what you normally do to safely lose altitude. It better be a way to safely lose height because you really can't tell much about the attitude of a dot, can you. You safely lose altitude (with luck) until you can see 2 dots again.

What is the rule? I never worked out formal wording for it.

I will tell you that the rule was worked out one evening. It was the evening of the day I flew my most favorite 2m of all time out of sight straight up. I yelled for help and had half the field searching the skies for it for A VERY LONG TIME. (my estimation of time, that is) It happened that a good buddy of mine spotted sunlight flashing WAY OFF TO THE EAST and used binoculars to spot that sucker. I flew it back following his "ground control."

I still got that plane. And use the 2-dot rule whenever luck permits.

da Rock

I've got a TX/RX setup with telemetry. I actually bought it to explore altitude questions for power planes at my favorite club field. We happen to be almost perfectly 270 from a private airport that's about 2 miles east of us. It's one runway is 9/27. Ain't that interesting. More interesting is since the runway isn't level, most of the regulars there prefer to land in one direction even when the wind isn't exactly cooperating. Guess which direction. So we often get local traffic coming over. In fact, I think they use our windsock and runway to guide on. anyway....

I also bought the telemetry stuff in case I ever get another chance to fly some RC glider cross country. I used to have a radio variometer that was used back in Minnesnowta in an unlimited for cross country. It's sound from the earbud was annoying. I figure to raise the technology bar given the opportunity. And to lose that painful tone.

I've used the radio to check out what 2K AGL looks like above my favorite field. It's quite easy to get to with even a .46 powered trainer. In fact, the test of the radio's telemetry included verification of altitude using something else that's available and useful. Hand held weather stations often have altitude readouts. My Kestrel 4000 not only gives a digital reading of altitude but graphs it as well. It's ridden aloft a number of times in a few different models. It's fun for everyone to guess how high the model went and have a way to prove who was closest. It's interesting also how seldom anyone is anywhere close to the right answer.

But if you are interested in knowing altitude nowadays, it's pretty easy to get the tools to find out.

da Rock

BTW, for those who plan to "measure" the size of the dot they see in the sky, it's not going to be easy or very accurate.

The sky has something to do with what we see. So do our eyes.

Our eyes are going to see the dot differently when the dot has white clouds behind it. They are going to see the dot differently when there is dark blue sky, and a third "differently" when it's light blue sky.

When I lost my 2m that fateful day.... The sky was about 40% cloud. It was one of the "cloud street" days. Lines of cumulus were up there from horizon to horizon. Awesome day for lift. The puffies were lined up like Crispy Crème Donuts coming out of that patented machine in parallel lines. Sort of like cobblestones with gaps. And above us instead of under our feet. The winds aloft were moving all the streets along in the same direction. Each donut/puffie followed exactly in the path of the one ahead. The one behind followed in line.

I was steering the dot straight down one of the streets and it seemed to move along under one of the puffies at it's same pace. No worries. (ignorance is bliss, right) When the dot and cloud were passing me overhead, I decided to put the nose down and run ahead to the next puffie. That worked like gangbusters. Unfortunately I didn't take notice of one thing. It was gonna cost me. I did that a couple of times in fact.

What I didn't notice was the dot was harder to see when it was in the blue between puffies.

Your eyes see a dot differently when it's in front of bright white compared to deep blue. In fact, you'd probably say the dot was smaller in front of blue than when in front of white. If you had really good eyes, you'd also notice a difference when the dot was up-sun compared to down-sun. And therein lies the problem.

The last run from one puffie to the next was the last run because the dot had gotten smaller and I hadn't noticed. It had gotten small enough that when it moved in front of the blue, it was too small for me to see. Of course, it wasn't really smaller at all. But my eyes could no longer see it thanks to the background.

So measuring what you can see in the sky isn't reliable at all.

Petepala1961

What kind of altitudes were you hitting when you recorded it and how far off were the guesstimates?

thanks and I enjoyed your posts.

pete

TexasAirBoss

My Feedback: (22)

1700' - 1800' with GPS telemetry.

jcstalls

My Feedback: (7)

HI,

About 6,000' AGL or so for me with a 100" slope racer.



Naturally I was standing at about 4,700' AGL. A little tougher flying at altitude.


Jared

SpeedsterDEN

14 days ago one from the club was in 3356 feet,with a 2,5 meter pure glider in termals, under a cumulus.
Measured with Jeti telemetri, and it was just a small .

Maylon

2340 ft. AGL measured with "How High" altimeter in a Radian. It specked out and I lost sight of it. Pulled stick to the corner and just kept my eyes on the spot in the sky where I lost it and got lucky and spotted it spiraling down. Exciting. Enjoyed ever minute of it. My 1st speck out.