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General control line discussion => Open Forum => Topic started by: Paul Taylor on July 21, 2013, 07:06:14 AM

Title: That was different
Post by: Paul Taylor on July 21, 2013, 07:06:14 AM
Late yesterday afternoon I took my force out to put in a few practice Flights. Winds were light. As I started the second outside square the plane seem to just fall off the corner I had no control but caught it halfway down in time to make the second turn. Never had that happen before but it made be get a lower bottom. Joe Gilbert gave me some good advice once, he said to fly down but not for very long. :-)


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Title: Re: That was different
Post by: Bill Little on July 21, 2013, 07:39:11 AM
Hi Paul,

Lots of things happen to us with these models that we cannot always identify the source.  The bottom turn on the outside squares (both in the "loops" or the Sq. 8.) is definitely a "timing event". 

I once went to a meet with a fairly new model and once I got into flying "Official Flights", the model seemed to not be able to turn an outside square.  Wow was I dancing on that handle just to keep the model out of the asphalt.  Never acted that bad ever again!  (but it really caused long term problems with that part of the pattern)

BIG Bear
RNMM/AMM
Title: Re: That was different
Post by: Bob Reeves on July 21, 2013, 08:33:22 AM
Sounds like wake turbulence to me. Why you see pilots steeping back in the middle of consecutive manovers in light or calm winds. The step back moves the airplane out of the previous flight path.
Title: Re: That was different
Post by: Paul Taylor on July 21, 2013, 09:22:24 AM
I think that was it Bob. I just never experienced it in that spot before. But then I've not been flying in the same spot twice in a row.  Guess my pattern is improving.  ;D
Title: Re: That was different
Post by: phil c on July 21, 2013, 11:46:38 AM
It can also have something to do with how hard you hit the upper left corner.  Depends on the model of course, but hitting the corner harder can slow the model down enough to affect the bottom corner.  If it slows too much it won't have enough energy to zoom through the bottom corner.
Title: Re: That was different
Post by: Paul Taylor on July 21, 2013, 12:36:41 PM
It can also have something to do with how hard you hit the upper left corner.  Depends on the model of course, but hitting the corner harder can slow the model down enough to affect the bottom corner.  If it slows too much it won't have enough energy to zoom through the bottom corner.

Maybe so. I've been known to bang a corner.
Title: Re: That was different
Post by: Randy Powell on July 21, 2013, 01:38:29 PM
Yep, I'd say wake turbulence. I had a USA-1 that came to it's end on second turn of the outside squares. Bounced it right off the tarmac.
Title: Re: That was different
Post by: Sean McEntee on July 21, 2013, 03:48:52 PM
Could have been wake turbulence, prop wash, an odd thermal, lots of factors when flying out in Mother Nature :)
Title: Re: That was different
Post by: John Stiles on July 21, 2013, 04:40:32 PM
I'd hafta agree with the wake turbulence, I've done that too many times to have an accurate county...makes a Ringmaster S-1 wallow pretty drastically. Also messes up a Super Clown bad enough it makes you wanna say a bad word. ;)
Title: Re: That was different
Post by: Curare on July 21, 2013, 07:42:26 PM
Yep, I'd say wake turbulence. I had a USA-1 that came to it's end on second turn of the outside squares. Bounced it right off the tarmac.

I did that this weekend, only mine didn't bounce.
Title: Re: That was different
Post by: RknRusty on July 22, 2013, 03:13:27 AM
Does a fair breeze at your back, say 7-10 mph eliminate wake turbulence?
I was doing consecutive 8s with my Shoestring yesterday with a good breeze. I don't remember the lines ever feeling light, but when I watched the video, I saw that I was taking a step back on each loop. I didn't even know I did it until I saw the video evidence.
Title: Re: That was different
Post by: Steve Helmick on July 22, 2013, 11:58:05 AM
Does a fair breeze at your back, say 7-10 mph eliminate wake turbulence?
I was doing consecutive 8s with my Shoestring yesterday with a good breeze. I don't remember the lines ever feeling light, but when I watched the video, I saw that I was taking a step back on each loop. I didn't even know I did it until I saw the video evidence.

The breeze would easily take care of it if it was really 7-10 mph, but people often overestimate wind speed. For mere mortals, 12 mph is a LOT to fly in, whether F1A or F2B. Many will say that a 12mph breeze is a 20 mph gale. I would speculate that if the model looked like it was hitting wake turbulence, you were actually hammering the controls too hard on corners, or making the round tricks too small, stalling the wing or tail to some degree. Avoid that! Flying 25' "bottoms" and 45 deg. "tops" is asking too much of the airplane.

When you get more comfortable with doing the tricks, start concentrating on what you do with your feet, before and during the trick. For example, moving your feet in the OH8 is NOT what you want to do (Attn: Rex Abbot). You really don't WANT to move your feet during any of the tricks, BUT when you do any consecutive maneuvers (except the OH8, obviously), you need to beware of wake turbulence when the wind is calm. When the wind picks up to where it accelerates the model and makes the line tension increase, you'll need to practise positioning yourself at the upwind side of the pilot's circle at the start of the trick and then following it downwind as the trick unfolds, to reduce line tension and reduce model's speed buildup. This is an important pilot skill, and I'm working on mine.  In the OH8, you can start at full height, arm extended, and do the 2nd OH8 a bit crouched with arm less extended, to give your plane "cleaner air".  There are a lot of flying tips in the Judging Clinic Forum, if you care to read up. Tho that really isn't the intent of the forum, it just seems to happen and is also helpful for those learning to be judgemental!  

One day, you'll find that your plane has excellent line tension in the OH8 on one flight and very little line tension on another flight. That there is the difference between a "thermal" and a "downdraft". As the breeze blows, the "lull" marks the downwind side of the thermal as it comes to you, and the stronger than normal breeze following the lull is the "infill". A thermal is a miniature twister or dust devil, which is in turn a miniature tornado. I've seen lawn chairs 50' in the air at free flight contests in California! Not good!   H^^ Steve

Edit: Flying on a pilot's circle that isn't flat and smooth makes all this stuff a lot harder...grass any worse than a soccer field is really tough, and tiring.
Title: Re: That was different
Post by: RknRusty on July 22, 2013, 01:26:22 PM
Thanks, Steve. I was no doubt making my loops too tight. I'm having some difficulty breaking my old sport freestyle 1/2A habits, where thrills and chills and blinding speed are the theme. As the day went on I gradually started using more air... until that last vertical 8 that wasn't quite high enough when my engine coughed. I was so enthralled in learning that trick, I neglected another lesson; keeping track of my fuel. HB~> Boy I have a lot to learn. Nothing worse than bent LG though.
Rusty
Title: Re: That was different
Post by: Steve Helmick on July 22, 2013, 02:49:28 PM
One of the benefits of flying "the pattern" is that you'll know when you're close on fuel. You can also tweek the tank to make it give more or less advanced warning of the impending shutdown. After doing that, you will cut your crashing and bashing a whole lot.

"Letting the airplane fly" (not making stuff too small and stalling it) will also help tremendously, because your line tension will be much more reliable. Altitude and line tension are good!  ~> Steve
Title: Re: That was different
Post by: john e. holliday on July 22, 2013, 07:38:30 PM
Thanks, Steve. I was no doubt making my loops too tight. I'm having some difficulty breaking my old sport freestyle 1/2A habits, where thrills and chills and blinding speed are the theme. As the day went on I gradually started using more air... until that last vertical 8 that wasn't quite high enough when my engine coughed. I was so enthralled in learning that trick, I neglected another lesson; keeping track of my fuel. HB~> Boy I have a lot to learn. Nothing worse than bent LG though.
Rusty


If all you got was bent landing gear,  you are luckier than me.   LL~ LL~ LL~
Title: Re: That was different
Post by: Steve Helmick on July 22, 2013, 09:41:35 PM
Right, John! I think I crashed more out of the V8 than any other maneuver. Sometimes it was PE, sometimes turbulence plus PE.

This weekend, we were relentlessly yelling "Watch the wind" (direction). Bad stuff often happens when pilots are not putting their tricks downwind. OTOH, sometimes it's calm and thermally and the wind is going different directions on every side of the circle. That's when judges have to relent to the pilot's opinion...and pilots need to signal the judges where they want to do their tricks. Often, judges are not aware of the signaling.  :o Steve