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-   -   How do you estimate height? (https://www.rcuniverse.com/forum/beginners-85/2824531-how-do-you-estimate-height.html)

paul_c 03-30-2005 06:15 PM

How do you estimate height?
 
Just curious how people estimate height. A telephone pole is 30 feet, but that's all I have for reference.

efergie72 03-30-2005 09:19 PM

RE: How do you estimate height?
 
Just curious as to why you need to get a heigth estimate?

Pilot Chad 03-30-2005 09:23 PM

RE: How do you estimate height?
 
I normally take a wild guess, after about 150 i have no idea.

paul_c 03-30-2005 10:04 PM

RE: How do you estimate height?
 


ORIGINAL: efergie72

Just curious as to why you need to get a heigth estimate?
For one reason, I've been looking at sailplanes, and people talk about reaching "x" number of feet in 60 seconds, etc. Just wondering how they are coming up with these numbers.

Fly-guy 03-30-2005 10:07 PM

RE: How do you estimate height?
 


ORIGINAL: paul_c



ORIGINAL: efergie72

Just curious as to why you need to get a heigth estimate?
For one reason, I've been looking at sailplanes, and people talk about reaching "x" number of feet in 60 seconds, etc. Just wondering how they are coming up with these numbers.
ever heard of an eagletree Flight data recorder? Google it then you will know how.

Fly-guy

paul_c 03-30-2005 10:08 PM

RE: How do you estimate height?
 


ORIGINAL: Fly-guy



ORIGINAL: paul_c



ORIGINAL: efergie72

Just curious as to why you need to get a heigth estimate?
For one reason, I've been looking at sailplanes, and people talk about reaching "x" number of feet in 60 seconds, etc. Just wondering how they are coming up with these numbers.
ever heard of an eagletree Flight data recorder? Google it then you will know how.

Fly-guy
Yeah, now that wasn't so hard now, was it?

GRANT ED 03-30-2005 10:35 PM

RE: How do you estimate height?
 
Height and distance are the most difficult things for a person to judge. I have heard of people saying " I flew my model to 2000 feet the other day". I would suspect that most people would overestimate height. I have flown over my model field at 1500 feet and the models on the ground were little specks. Way to far away to control properly.

britbrat 03-31-2005 10:08 AM

RE: How do you estimate height?
 
Our runway is 200' long, so I try to visualize the number of runway lengths (or fractions) above ground. Crude, but it works (I think).

Crashem 03-31-2005 11:52 AM

RE: How do you estimate height?
 
Estimating hieght and or distance accurately usually requires a reference. Britbrat uses the runnway I use the tree line surrounding the field.

jcankur 03-31-2005 11:55 AM

RE: How do you estimate height?
 

ORIGINAL: britbrat

Our runway is 200' long, so I try to visualize the number of runway lengths (or fractions) above ground. Crude, but it works (I think).
Human eye has different depth perception in the horizontal and vertical planes. Objects 150' high seem much far away than 150' away in the same horizontal plane. So a plane visualized to be one runway length (200') high might be at 80' or who knows how high.

jcankur 03-31-2005 11:59 AM

RE: How do you estimate height?
 

ORIGINAL: Crashem

Estimating hieght and or distance accurately usually requires a reference. Britbrat uses the runnway I use the tree line surrounding the field.
IMO that's a better reference. When flying low I use other people (6' to 7' tall) as reference. A plane flying as high as my eyes are is 5' to 6' above the ground.

Commander_Drake 03-31-2005 01:35 PM

RE: How do you estimate height?
 
For sailplanes I have seen people use reference cards that they hold at arms length. You match the picture on the card with the apparent size of your sailplane and it gives you an estimate of the height (or distance from you). I think they made these cards up themselves. I don't know if they can be purchased.

You could easily do it by setting the sailplane on the ground with its nose toward you and measure out a distance like 100 feet, then hold up an index card at arms length so that it looks to be just under the plane and mark the ends of the wingtips on the card and write 100 feet under it. Repeat for other distances.

Not too accurate but it's cheap.

iacolb12 03-31-2005 01:53 PM

RE: How do you estimate height?
 
I haven't got a plane yet but a piece of advise I heard was to fly as high as you can comforatbly see the plane. Meaning still being able to tell the direction and not give you neck pains when you do venture closer to your position.

The guy who told me that was training someone that day. The plane was some high wing homebuilt trainer that had a 76" wingspan and the plane looked as small as a parkflyer they had it so high.:D

I think that'll be my rule of thumb when I start crashing... err, flying.

paul_c 03-31-2005 02:04 PM

RE: How do you estimate height?
 


ORIGINAL: Commander_Drake

For sailplanes I have seen people use reference cards that they hold at arms length. You match the picture on the card with the apparent size of your sailplane and it gives you an estimate of the height (or distance from you). I think they made these cards up themselves. I don't know if they can be purchased.

You could easily do it by setting the sailplane on the ground with its nose toward you and measure out a distance like 100 feet, then hold up an index card at arms length so that it looks to be just under the plane and mark the ends of the wingtips on the card and write 100 feet under it. Repeat for other distances.

Not too accurate but it's cheap.

Thank you all, good info. I like Commander_Drake's idea. I might try this with a slow sailplane that I'm getting; any other plane might be too difficult (I usually need both hands on the controls!)

FLYBOY 03-31-2005 02:50 PM

RE: How do you estimate height?
 
As you can see, most people use the WAG method. In all realistics, if you don't use some sort of data recorder that uses a GPS or something to measure dist acurately, you won't be close. I have had people call the tower many times when I am doing jobs over town and they always say we are 50 feet above their roof. The tower usaully tells me about the call, but I am on radar and am at between 1000 and 1500 usually.

Very very few can accurately judge distance when it gets more than a few feet from them.

britbrat 03-31-2005 02:55 PM

RE: How do you estimate height?
 
Golfers are pretty good at measuring horizontal distances. I can tell when my plane is a 5 iron away.

SwampFlier-RCU 03-31-2005 04:24 PM

RE: How do you estimate height?
 
ROFLMAO BRIT BRAT :D:D:D

FLYBOY 03-31-2005 06:40 PM

RE: How do you estimate height?
 


ORIGINAL: britbrat

Golfers are pretty good at measuring horizontal distances. I can tell when my plane is a 5 iron away.

Never thought of that, but then when I go to a new course, I suck at it again, so I think it goes back to the point of ref. I know the course pretty well at the lake, so I can do it well there, but the ones here, I can never get it right because I only play them once or twice a year. the 150 bush moves every time I get to it so I can never hit the green. Yea, thats it. :)

britbrat 03-31-2005 06:50 PM

RE: How do you estimate height?
 
The problems come when it's in an inverted flat spin -- a lob-wedge high.

Pilot Chad 03-31-2005 08:19 PM

RE: How do you estimate height?
 
britbrat, I would say a wood tee high and many of them:D

britbrat 04-01-2005 07:10 AM

RE: How do you estimate height?
 
The tee-high stuff is for low-inverted passes -- but ya gotta stay awake.

FLYBOY 04-01-2005 10:14 AM

RE: How do you estimate height?
 


ORIGINAL: britbrat

The tee-high stuff is for low-inverted passes -- but ya gotta stay awake.

But your rudder can only be 3 paint thicknesses from the ground on that pass. [8D]

britbrat 04-01-2005 12:51 PM

RE: How do you estimate height?
 
Agreed:D

rcjon 04-01-2005 04:42 PM

RE: How do you estimate height?
 
If you spot a tall communications tower drive to it, if possible. The tower owner and a tower number will be on the fence. You can then use your friendly Internet and Google to find the company and the data for that tower. I found that the one behind my office is 540 feet tall. I look at it frequently and try to take that reference to the flying field.

Our flying field is within a couple of miles of an airport. Purportedly, we are supposed to not fly over 400 feet (and so you know that never happens.) This has lead to several discussions at the field about how high 400 feet was. So when I'm on break behind the office I studied this communications tower that is approximately 1/4 mile from the office. One day we used a laser range finder and trigonometry to estimate a height of just over 500 feet for the tower. I didn't believe the estimate - I didn't think it could be that tall - but we rechecked the calcs - and eventually I drove over to the tower and got information from the gate that enabled me to look the tower up on the Internet and get all its vitals.

All I can say is that when you translate that tower height to our flying field, 400 feet ain't very high.;)

I've heard that on occasion the control tower has sent the sheriff's department over to the field to caution R/C flyers to fly lower. Our field is not under the usual landing pattern, but sometimes we have Cessnas coming right over us on their base leg and we start screaming "Full Scale! Full Scale!"

paul_c 04-02-2005 08:22 AM

RE: How do you estimate height?
 


ORIGINAL: rcjon

If you spot a tall communications tower drive to it, if possible. The tower owner and a tower number will be on the fence. You can then use your friendly Internet and Google to find the company and the data for that tower. I found that the one behind my office is 540 feet tall. I look at it frequently and try to take that reference to the flying field.

Our flying field is within a couple of miles of an airport. Purportedly, we are supposed to not fly over 400 feet (and so you know that never happens.) This has lead to several discussions at the field about how high 400 feet was. So when I'm on break behind the office I studied this communications tower that is approximately 1/4 mile from the office. One day we used a laser range finder and trigonometry to estimate a height of just over 500 feet for the tower. I didn't believe the estimate - I didn't think it could be that tall - but we rechecked the calcs - and eventually I drove over to the tower and got information from the gate that enabled me to look the tower up on the Internet and get all its vitals.

All I can say is that when you translate that tower height to our flying field, 400 feet ain't very high.;)

I've heard that on occasion the control tower has sent the sheriff's department over to the field to caution R/C flyers to fly lower. Our field is not under the usual landing pattern, but sometimes we have Cessnas coming right over us on their base leg and we start screaming "Full Scale! Full Scale!"
Very interesting story. I would have thought that most people overestimate height, but you say that in your experience, 400 feet isn't very high. I'm going to try to find some frame of reference also. Thanks.


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