Its a FAQ(t), Sunday Slopers wanted

[GLIDERGIDER]

Sunday is starting to shape up for sloping. We are getting set for a trip to the PowerLineCut. Hope to get some interest. I've got 3 other guys that are going, so if you want some fun, put a devit on your calender for Sunday.
Dave

[GLIDERGIDER]

So what, 12 looks and nobody replys? Where did all my slope buds go?

[FlyH2O]

Any time on Sunday is good for me. :D

Larry O

[SU Jags]

I should be able to make it, got directions?

[atjurhs]

You know I'm in. I'll be "Oscar Mike" at 1pm. That's Marine talk for on my way.....

[Miderror]

Looks like the wind is on for Sat. 17 with a 170 azimuth at noon and 37%rain.

I might take my Tx,a batt and a roll of tape to the retrieval sight.

Don

[GLIDERGIDER]

Looks like the wind is on for Sat. 17 with a 170 azimuth at noon and 37%rain.
I might take my Tx,a batt and a roll of tape to the retrieval sight.
Don
Yeah, I'll go help you with the retrieval. Noon is good.
SUJag: PM if you want to go on Sat. Have you done a hand launch yet?

[atjurhs]

Dave,

Will there be a BPS at the Cut Line Sunday?

[GLIDERGIDER]

Dave,
Will there be a BPS at the Cut Line Sunday?
Todd,
Yes, I'm still planning to fly on Sunday.

I'm supposing you are kidding about the BPS- to windy for those. Although next summer, when the winds die down, the BPS might just be the ticket for a cheep and easy light wind sloper.

[SU Jags]

Nope, no handlaunch yet. I plan to do that in hallway of my Dept. this evening. So today is no good for me.

[Miderror]

Dave, you have a Google Earth point for Power Line Cut?

[SU Jags]

And driving directions from Meridian St. in North HSV.

[dee-grose]

Dave, I never heard a flight report on this...did ya'll go?

[atjurhs]

Dave, Larry, Wallace and myself flew, or tried to. The winds were very on-off. There were massive elevators and then nothing. Light floaters did fine, wish I had my mini-weasel with me. Wallace tried to maiden his coroplast Beetle, but there wasn't enough wind for it. Larry had a chance to fly his giant "Mother Ship", but all of us went down the cliff several times in retrieval mode, some more times than others. Oh yes, I think I got the award for most times hitting a power line with 9, twice I had double hits.

The best part of that flying day was the beer and burgers that followed afterwards. We had a nice BBQ over at Dave's. Too bad you missed out.

BTW, three of us also flew Friday night at the quarry. My Moth got her first injury (but just cosmetic), and I hit Don with my Raider (don't believe if he tells you otherwise). Dave took down Don's Zagi by knocking off one of his control horns. Although it was NW winds that started off smooth they too became a bit shifty, turbulent, and spotty. Goes to show you never know what you're going to get when you got to the slope - part of the fun.

[GLIDERGIDER]

Todd,
Good writeup on last Sunday. Larry is the only one of us that had a light wind sloper. Although we get lots of unlimited lift days, last Sunday was not one of them. I will repeat a message I hear from Don Miller about every time I fly with him. Build it light, fly it light.

That message was brought home last Sunday to all of us fliers, and particularly to Wallace. Wallace had his coroplast plank. It was a maiden flight day for him, but just as soon as I hefted the plank I knew it wasn't going to be good. Given the light lift conditions, a successful maiden flight was not possible. Also, this coroplast bird configuration is very difficult to get a CG dialed in. To compensate for the CG location, Wallace had to add nose weight. Because there is no fuseage, that weight had to be large.

For those reasons, I don't recommend a plank wing for a first time sloper. Instead, I say to get a delta wing EPP kit. The Weasel Pro might be the only exception, and it does have a fuselage to help balance and keep the bird light. Still, the CG location for a plank is very critical and not recommended for the first time sloper.

Dave, I never heard a flight report on this...did ya'll go?

[SU Jags]

For those reasons, I don't recommend a plank wing for a first time sloper. Instead, I say to get a delta wing EPP kit. The Weasel Pro might be the only exception, and it does have a fuselage to help balance and keep the bird light. Still, the CG location for a plank is very critical and not recommended for the first time sloper.

You mean one like this? Yes, this is the Overlord I got from Todd. It's now wearing the official SU color pattern :D ; the re-build required a good amount of glue so it's not super-duper light. The test glides went extremely well though, ~ 40-50yds hands off. Now I just need that wind to blow.

[atjurhs]

The OverLord Flys again! Yea baby :D

Except for the ugly UCLA color scheme :p (I'm from USC), she'll fly beautifully!

[GLIDERGIDER]

Wallace:
That Overlord is exactly what you need. If you can go 40-50 yds, you are ready for the slope. The rebuild looks great.

Todd, It looks like you found a perfect home for your Overlord.
Think big wind
Dave

You mean one like this? Yes, this is the Overlord I got from Todd. It's now wearing the official SU color pattern :D ; the re-build required a good amount of glue so it's not super-duper light. The test glides went extremely well though, ~ 40-50yds hands off. Now I just need that wind to blow.

[SU Jags]

The OverLord Flys again! Yea baby :D

Except for the ugly UCLA color scheme :p (I'm from USC), she'll fly beautifully!

You sure you're not just a little bit of a UCLA fan? It did have blue & gold covering on it when I got it from you. :p Thanks again, I'll try to keep it out of the trees. ;)

[atjurhs]

Those colors are why I liked flying it into the rocks of the quarry :D

[wheatfly]

http://www.engineeringvillage2.org.fetch.mhsl.uab.edu/controller/servlet/Controller?CID=quickSearchAbstractFormat&SEARCHID=40afb910a1ee3c82cM3377prod2data1&DOCINDEX=1&PAGEINDEX=1&database=1&format=quickSearchAbstractFormat

Just an artical for someone that wants to really over engineer dynamic soaring.

Hear is another one that might be interesting.

http://www.engineeringvillage2.org.fetch.mhsl.uab.edu/controller/servlet/Controller?CID=quickSearchAbstractFormat&SEARCHID=40afb910a1ee3c82cM3377prod2data1&DOCINDEX=2&PAGEINDEX=1&database=1&format=quickSearchAbstractFormat

[atjurhs]

The URLs lead me to a loging screen for Sterne Library Resources at UAB; apparently, you have to have an account with those folks to log into to retrieve the articles :(

[wheatfly]

hhhmmmmm here is the first abstract


Abstract: This paper presents optimal patterns of glider dynamic soaring utilizing wind gradients. A set of three-dimensional point-mass equations of motion is used and basic glider performance parameters are identified through normalizations of these equations. In particular, a single parameter is defined that represents the combined effects of air density, glider wing loading, and wind gradient slope. Glider dynamic soaring flights are formulated as non-linear optimal control problems and three performance indices are considered. In the first formulation, the completion time of one cycle of dynamic soaring is minimized, subject to glider equations of motion, limitations on glider flights, and appropriate terminal constraints that enforce a periodic dynamic soaring flight. In the second formulation, the final altitude after one cycle of dynamic soaring is maximized subject to similar constraints. In the third formulation, the least required wind gradient slope that can sustain an energy-neutral dynamic soaring flight is determined. Different terminal constraints are used to produce basic, travelling, and loiter dynamic soaring patterns. These optimal control problems are converted into parameter optimization via a collocation approach and solved numerically with the software NPSOL. Different patterns of glider dynamic soaring are compared in terms of cycle completion time and altitude-increasing capability. Effects of wind gradient slope and wind profile non-linearity on dynamic soaring patterns are examined. Copyright © 2004 John Wiley and Sons, Ltd. (23 refs.)

[wheatfly]

and the second one.

Abstract: This paper studies optimal powered dynamic soaring flights of unmanned aerial vehicles (UAVs) that utilize low-altitude wind gradients for reducing fuel consumptions. Three-dimensional point-mass UAV equations of motion are used, and linear wind gradients are assumed. Fundamental UAV performance parameters are identified through the normalization of the equations of motion. In particular, a single wind condition parameter is defined that represents the combined effect of air density, UAV wing loading, and wind gradient slope on UAV flight. An optimal control problem is first used to determine bounds on wind conditions over which optimal powered dynamic soaring is meaningful. Then, powered UAV dynamic soaring flights through wind gradients are formulated as non-linear optimal control problems. For a jetengined UAV, performance indices are selected to minimize the average thrust required per cycle of powered dynamic soaring that employs either variable or constant thrust. For a propeller-driven UAV, in comparison, performance indices are selected to minimize the average power required per cycle of powered dynamic soaring with either variable or constant power. All problem formulations are subject to UAV equations of motion, UAV operational constraints, proper initial conditions, and terminal conditions that enforce a periodic flight. These optimal control problems are converted into parameter optimization with a collocation method and solved numerically using the parameter optimization software NPSOL. Analytical gradient expressions are derived for the numerical solution process. Extensive numerical solutions are obtained for a wide range of wind conditions and UAV performance parameters. Results reveal basic features of powered dynamic soaring flights through linear wind gradients. Copyright © 2004 John Wiley and Sons, Ltd. (26 refs.)