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Old Jan 26, 2009, 02:28 PM
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fnnwizard's Avatar
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Quote:
Originally Posted by jrerickson
Tuan,

Taking a video of your yaw string is an interesting idea. I've got news for you, however. To keep that string straight you can't just do it with your right thumb. Unless you can program your radio to take speed and diameter of turn into account you are not going to have a fully coordinated turn.

I fly uncoupled with very little differential. I use my left thumb a lot. Sequence for a turn is right thumb to establish bank, add rudder, reduce rudder and bank out.

Flying at really high altitude or when you are just flying casually you can throw on the rudder/aileron mix, but I really think it makes you a better pilot to work on the coordination of thumbs. In hand launch this becomes really apparent, especially when turning close to the ground.

Excessive yaw, either in or out, is as bad as excessive bank. Both are lift killers.

John
Exactly John, I emphasize left thumb... did I write right thumb somewhere... ?

You scared me thinking I had written right thumb somewhere... I looked and see that I didn't so there.
Am really glad you are confirming what I am experiencing.
Tuan

Quote:
Originally Posted by fnnwizard

Anyhow, I still use A/R mix but mixed at rate that makes rudder move lots in beggining of ail movement, but it's on a switch and it gets turned on when I am at limits of my vision without height and for when I let others try my plane. Also, in normal flying I will start the turn will rudder just before adding ail as needed to keep bank angle. So far the X needs almost zero ail once in a thermal bank or even opposite, I just thought about this now, when in opposite your diff is actually working against you.

Tuan.
I need to clarify "lots in beginning..." lot's here was meant to say lots more in beginning of ail movement then say middle of ail movement... if that makes any additional sense... Also trying to say when adding opposite ali to hold a bank, diff is working against .
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Old Jan 26, 2009, 02:44 PM
agony sweetns the victory
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Where can I buy a yaw string for my Xplorer Wouldn't that be great to have a yaw string on these birds! Maybe that's a business I could start during these economic hard times Ahhhhh, the feds would probably come after me.....
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Old Jan 26, 2009, 02:53 PM
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United States, CA, Midway City
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Quote:
Originally Posted by atjurhs
Where can I buy a yaw string for my Xplorer Wouldn't that be great to have a yaw string on these birds! Maybe that's a business I could start during these economic hard times Ahhhhh, the feds would probably come after me.....
Well, I just picked up 5 more of the flycam this morning to do the Xperiment. I'll hook up 4 cams to the Xplorer to record and will post. Should be interesting and fun.

Here's a youtube video of someone:

http://www.youtube.com/watch?v=Ri6dnjrq8Lg
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Last edited by fnnwizard; Jan 26, 2009 at 03:19 PM.
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Old Jan 26, 2009, 03:09 PM
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Johns comments are pretty much right on, as are Tuans observations. I am thinking that John's Hand Launch experience is being applied to his thermal flying. I too advocate less Rudder to Aileron mixing. When I have other people take a turn on my models, I often see them stalling around as they try to tighten up the circle. I suggest you use as much Rudder to Aileron mixing as necessary to suit your comfort level. Learn to recognize that too much Rudder added to a circle will speed the model up and screw it in to the ground. You are better off to use less rudder coupling and add Rudder in to the circle as you need it. The restriction will be your vision, since you have to really be able observe your model to be able to circle out at the limits of your vision uncoupled. If you find the model getting out of sorts at the fuzzy range, you can add a little more R-A mixing to keep it easier to manage. If you find yourself out there to often you might consider a little expo to soften the control jabs a little too! Remember Handling Trumps Max performance,since unintended inputs kill performance. Larry
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Old Jan 26, 2009, 03:55 PM
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Larry, do your R/A mixing comments go along with a model that requires outboard aileron to keep from continuing to roll? Not my Xplorer but another model wants to continue to increase the roll angle as it goes around the turn, so I have to feed it outboard aileron while holding elevator. Or is this more related to aileron differential???

Todd
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Old Jan 26, 2009, 04:58 PM
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Todd,
I would have to fly the specifice setup , but the indication you have mentioned sounds like spiral instability, to much dihedral or to little vertical tail volume. I am trying to think where to much Diff might cause the problem but the negative aileron is usually much more benign, compared to much positive Aileron causing Nose swings. For further discussion contact me offline, I don't want to discuss a model I have no experience with. In regards to the Explorer it is a very well mannered airplane that should reward their owners with many satisfying flights. LJ
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Old Jan 26, 2009, 05:03 PM
jrerickson
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Valencia, CA
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Quote:
Originally Posted by fnnwizard
Also add that using Mark's theory, if you do this with no diff, more rudder, the "decresase in altitude" should happen over a longer peiod of time, so in essence x% better. The important part is; is this x% better worth the extra effort of using left thumb more and having more pilot workload?
I thought when you were talking about "pilot workload" it meant you didn't like using your left thumb. That's where I was coming from.

John
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Old Jan 26, 2009, 05:17 PM
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Oh yes indeed Larry, the Xplorer is an amazing flying airplane!

Here's a pic of mine before or after her maiden flight. Can you see me smiling

A friend (who's very good searching RCGroups and Mark Drela posts) pointed me to a number of Mark's posts on the differential debate. I guess I'll have to give it a try.......

And now back to our Xplorer specific postings....
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Old Jan 26, 2009, 05:39 PM
or F, J, K, or even TD
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Hey guys, for what it's worth, the tendancy for a glider to increase its bank while in a circling type of turn, really any turn for that matter, is that the outboard wing has a faster airspeed than the inside wing, and thus it generates more lift. If the turn is properly coordinated this will happen. When applying opposite aileron to maintain wing bank angle in a turn the coupled A/R acts to yaw the glider out of the turn, or cause slip, not tighten the turn to cause skid, or spiral it out of the sky. More A/R coupling helps to coordinate the roll manuever to enter the turn. Once in a constant energy, constant bank angle turn, then less A/R mix would be helpful. But you could simply push on the rudder stick to keep the fuselage level throughout the turn as you apply outside aileron (called cross control) Easy to learn to do too.

2 cents from me.

Cheers,

Mike
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Old Jan 26, 2009, 06:43 PM
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Quote:
Originally Posted by atjurhs
Oh yes indeed Larry, the Xplorer is an amazing flying airplane!

Here's a pic of mine before or after her maiden flight. Can you see me smiling

A friend (who's very good searching RCGroups and Mark Drela posts) pointed me to a number of Mark's posts on the differential debate. I guess I'll have to give it a try.......

And now back to our Xplorer specific postings....

So leadfoot, thats the face behind all the questions.
JT
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Old Jan 26, 2009, 07:04 PM
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JT, you know "atjurhs" is aka grasshopper, or did I graduate to MudMinow???

Yes, that the ugly mug that's been taking the conventionally accepted aileron diff approach, but after reading many of MD's posts on the topic may just give the alternative method a shot.

BTW, that bright orange really showed up nicely in the gray sky!
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Old Jan 27, 2009, 06:40 AM
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Birmingham, AL
Joined Sep 2003
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Todd:

Did you decide on any trim colors for the bottom of the Explorer wing? I saw where you were considering vinyl tape for a white stripe on the underside of the wing. I tried some vinyl tape I got from an auto custom shop for some stripes on my Superior wing tips. It went on easy enough but was kinda thick. I ended up taking it off and using the monokote stick on trim. It worked well and is still on there and looks good.

John
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Old Jan 27, 2009, 10:24 AM
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Hey John,

I was planning on trying the monokote stick on trim on a leftover wingtip panel (from a different plane) later tonight. You just used Windex and monokote stick on trim, right?

The other question I have is chrome or white? I'm leaning towards white, unless someone stands up and swears how wonderful chrome stands out???
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Old Jan 27, 2009, 11:25 AM
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No Windex needed. There is a good adhesive surface present after you peel off the paper backing. Sticks firmly right to the gelcoat with some gentle pressure. I used a credit card to smooth it on and avoid bubbles.

I have been underwhelmed with reflective surfaces on the underside of the wing. It just mirrors the ground most of the time and shows up dark at altitude. The leading edge if trimmed with chrome does provide some flash on turns into the sun, but I always worried about dirtying up the leading edge with trim material. Maybe unfounded.
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Old Jan 27, 2009, 04:30 PM
Fly R/C writer
Redlands, Ca
Joined Dec 2004
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Hi Sleep4,

You can use a thinner vinyl that is just as opaque but thinner. Most of the vinyl used by sign shops and the like is known as intermediate vinyl. This is anywhere from 3-mils to 5-mils thick, on average. If you go for high performance vinyl, it will be from 2-mils to 3 mils thick. You can feel this difference quite easily. Also, high performance vinyl typically has a better finish to it and will withstand direct sunlight for up to 7 years without peeling, cracking, or fading. I use this stuff for cutting vinyl lettering on my planes, like AMA number, aircraft name, tail lettering, etc. People who attend Visalia normally see me out there cutting lettering for them in a small booth. High performance vinyl is more expensive, but you get better handling, stability and it is thinner...and I would recommend white, as the reflective stuff just doesn't providde the effect you are looking for, which is contrast so you can see the plane easier.

Mike
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