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Old Mar 20, 2013, 02:52 PM
in awe of glide...
Kirkerik's Avatar
United States, NY, DeRuyter
Joined Dec 2012
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DlG maximum airspeed

I understand that it depends on the structure and drag of the craft, not to mention many other factors.

But has anyone ever measured or simply have a good idea of the maximum airspeed of a dlg in a dive?

Kirk
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Old Mar 20, 2013, 02:56 PM
hot air rises...
jfinch's Avatar
Pleasant Grove, UT
Joined Jul 2005
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I don't know but I think it's less than launch 'cause if I dive vertically from say 500 ft and pull up just before I splat I don't end up as high as I do from a launch.
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Old Mar 20, 2013, 03:02 PM
Will fly for food
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Bellevue WA,
Joined Dec 2003
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I have measured DLG's at release doing 70+ MPH. I would think in a down line they may get to 60mph but I have not measured it.
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Old Mar 20, 2013, 03:59 PM
G_T
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Joined Apr 2009
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I've achieved far higher than launch speeds with the original Zone, ballasted. But, I don't have measurements. One can estimate it from wing drag coefficients and putting in a healthy margin for tails and fuselage. Within reason, max speed is proportional to the square root of the weight.

Gerald
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Old Mar 20, 2013, 04:16 PM
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United States, CA, Tehachapi
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Never clocked a DLG in a dive, but I know that the 14oz Blaster 2 I used to fly would really haul. Certainly faster than I was launching it. My 7.5oz Mystic prototype I don't think could quite reach launch speed in a dive.

Basically, at terminal velocity in a dive the weight of the plane is equal to the total drag force on the plane. Drag increases with the square of velocity, so if you do a little algebra you can see that terminal velocity is proportional to the square root of the weight, just like G_T said. So if you ballast a plane it'll have a higher terminal velocity.
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Old Mar 20, 2013, 06:06 PM
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Reno Nevada
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Normally, the max speeds I get are a fraction of a second before the plane blows up.
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Old Mar 20, 2013, 07:05 PM
a.k.a. Bob Parks
Glendale, AZ
Joined Jun 2008
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Mine is always an inch above ground!
BP
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Old Mar 20, 2013, 08:06 PM
Who needs a pilot??
danstrider's Avatar
Alexandria, VA
Joined Jul 2002
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Someone should put in a How-Fast, catch a boomer, then bail at altitude and hold a vertical downline as long as seemingly possible! Video is of course a requirement so we can all witness if there is destruction or not :-) I somewhat think we might throw close to or over terminal velocity anyway. So that means if someone mails me a loaner how-fast, I'd be happy to volunteer.

Dan
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Old Mar 20, 2013, 09:03 PM
in awe of glide...
Kirkerik's Avatar
United States, NY, DeRuyter
Joined Dec 2012
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Thanks for all your replys. I did a search but was surprised i did not find any threads on maximum airspeed. The airspeed indicator is something to definitely keep an eye on.
Quote:
Originally Posted by G_T View Post
I've achieved far higher than launch speeds with the original Zone, ballasted. But, I don't have measurements. One can estimate it from wing drag coefficients and putting in a healthy margin for tails and fuselage. Within reason, max speed is proportional to the square root of the weight.

Gerald
Quote:
Originally Posted by bwill6 View Post
Never clocked a DLG in a dive, but I know that the 14oz Blaster 2 I used to fly would really haul. Certainly faster than I was launching it. My 7.5oz Mystic prototype I don't think could quite reach launch speed in a dive.

Basically, at terminal velocity in a dive the weight of the plane is equal to the total drag force on the plane. Drag increases with the square of velocity, so if you do a little algebra you can see that terminal velocity is proportional to the square root of the weight, just like G_T said. So if you ballast a plane it'll have a higher terminal velocity.
It makes sense, the more weight, the more velocity. More velocity in turn more drag...which at some point terminal velocity is acheived. That's my simplified version...
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Old Mar 20, 2013, 09:05 PM
in awe of glide...
Kirkerik's Avatar
United States, NY, DeRuyter
Joined Dec 2012
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woo hooo!

Quote:
Originally Posted by Thermaln2 View Post
Normally, the max speeds I get are a fraction of a second before the plane blows up.
Quote:
Originally Posted by bbbp View Post
Mine is always an inch above ground!
BP
That sounds like some balistic flying!!
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Old Mar 20, 2013, 09:10 PM
in awe of glide...
Kirkerik's Avatar
United States, NY, DeRuyter
Joined Dec 2012
170 Posts
NIce find!

Quote:
Originally Posted by danstrider View Post
Someone should put in a How-Fast, catch a boomer, then bail at altitude and hold a vertical downline as long as seemingly possible! Video is of course a requirement so we can all witness if there is destruction or not :-) I somewhat think we might throw close to or over terminal velocity anyway. So that means if someone mails me a loaner how-fast, I'd be happy to volunteer.

Dan
That is great! Maybe we buy one or two of them, send them around to whoever wants do the vid and record their maximum airspeed.

i can't say i'm up for organizing it, but that would be fun. Good idea Dan.
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Old Mar 21, 2013, 12:33 AM
a.k.a. Bob Parks
Glendale, AZ
Joined Jun 2008
2,383 Posts
It could be calc'd off a BTOA graph. It shows min/max heights and time between two points, but on my setting only to the nearest half second, so not very accurate. If I did it correctly, my partially flapped descent from altitude was about 32 MPH.

What does the vario number between two points represent?

BP
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Old Mar 21, 2013, 09:21 AM
Chuck 'Em and Chase 'Em
Fly2High's Avatar
United States, NY, Plainview
Joined Aug 2005
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Why?

For what purpose would this be important?

Afterall, sailplanes are designed to find lift. As with everything, there are tradeoffs. If you want to work lift, you can do it more easily if you are light but light weight without a power source means that flightspeeds tend to be slower.

then again,if there is some fascet that might be interesting, please enlighten us all so we all may partake!!!
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Old Mar 21, 2013, 09:26 AM
Time for me to Fly...
Mr. Wiz's Avatar
United States, MI, Fenton
Joined Jan 2000
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Quote:
Originally Posted by Fly2High View Post
Why?

For what purpose would this be important?

Afterall, sailplanes are designed to find lift. As with everything, there are tradeoffs. If you want to work lift, you can do it more easily if you are light but light weight without a power source means that flightspeeds tend to be slower.

then again,if there is some fascet that might be interesting, please enlighten us all so we all may partake!!!
Sometimes it's fun just to satisfy a curiosity. I'd like to know how fast they can fly too.

I wonder how fast you could get one to go with one of your rocket engines on it, Gerald.
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Old Mar 21, 2013, 11:38 AM
G_T
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Vaporized.
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