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Old Apr 24, 2010, 11:42 AM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Icon 2 launch help....

Dan,

You wrote: "My first launch was close to disaster"

What is your CG? Where is your towhook? Have you given it a hand toss to make sure the elevator is close to the neutral point? About 2.75" up from fuse bottom to trailing edge of stab for the latest thick stab....
What happened on launch? correct appropriately.....

You wrote: "Right now my flaps are at 10mm down and ailerons follow them."

This is a good starting point for AG airfoil. Similar to the Supra, about 1 degree per 1 mm which puts you at about 10 degrees. After you figure
out the above then start playing with you flaps for optimization.
My launch flap setting is optimized at about 12 degrees....for my CG and towhook position for my Icon 2.

You wrote:"The elevator is 1.5mm down or perhaps a little more."
I like to get all my planes to launch well with a cruise elevator setting that I have determined through flight testing. Thus there is little if any change in elevator setting for launch.

Also sometimes a bad throw on launch can cause disaster on a well tuned model. Once you do the hand toss and get everything where you want it, have someone else (you trust) to throw it for you first time on the winch.

Hope this helps.

Jon
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Old Apr 24, 2010, 01:04 PM
Registered User
Tuomo's Avatar
Jyvaskyla, Finland
Joined Aug 2003
2,449 Posts
Quote:
Originally Posted by JP-Soar View Post
You wrote:"The elevator is 1.5mm down or perhaps a little more."
I like to get all my planes to launch well with a cruise elevator setting that I have determined through flight testing. Thus there is little if any change in elevator setting for launch.
Maybe he refers to the very common way of mixing little down elevator with launch camber? This is done to compensate the nose up effect of flaps/ailerons down. When you pull the flaps up to neutral, elevator goes down, keeping more pressure on the wing. I trim my lauch camber elevator setting with flying around at lauch mode. Plane should keep floating nicely with all launch camber settings, trailing edge down and neutral.

Sorry, this is not spesific to Icon 2
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Old Apr 24, 2010, 01:22 PM
They call me Crash!
Kaw1000's Avatar
Ohio
Joined Jun 2006
1,693 Posts
I'm at work but the cg is where the Manuel said it should be. The tow hook is pretty far in front of cg. The end of the tow hook is even with the cg. I have 4 flights on it and I feel it flies straight and level. I did do quite a few hand launches and it settled on
the tow hook on landing with no transmitter input.

My 1st launch on a gusty day, it went almost vertical and then tip stalled to the right.
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Old Apr 24, 2010, 01:24 PM
They call me Crash!
Kaw1000's Avatar
Ohio
Joined Jun 2006
1,693 Posts
Quote:
Originally Posted by Tuomo View Post
Maybe he refers to the very common way of mixing little down elevator with launch camber? This is done to compensate the nose up effect of flaps/ailerons down. When you pull the flaps up to neutral, elevator goes down, keeping more pressure on the wing. I trim my lauch camber elevator setting with flying around at lauch mode. Plane should keep floating nicely with all launch camber settings, trailing edge down and neutral.

Sorry, this is not spesific to Icon 2
Yes that is what I was refering to.
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Old Apr 24, 2010, 02:03 PM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Icon 2 Launching

Dan,

You wrote: I'm at work but the cg is where the Manuel said it should be."

My manual is version 2.2 and suggest a 106mm starting CG. This is very conservative for the 4 generation stab. Check yours to be sure. Do you have a 4th generation stab? Very thick in middle and should weigh about 2.4 oz. Round part of V-mount should face back torward the fin.

I fly at cg 112 which I like for long distance F3J flying. It indicates lift well but the pilot load is still low and I don't need constant adjustments when thermals/active air is encountered.

There have been many suggestion of CG for the different versions of the ICON 2 in various versions of the manual. These had a wide range from 106 to 119 which is crazy back....

I think Don Peters needs to update the current manual as their are a few discrepencies due to the continuous tinkering/evolution of this bird...

Jon
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Old Apr 24, 2010, 02:43 PM
They call me Crash!
Kaw1000's Avatar
Ohio
Joined Jun 2006
1,693 Posts
I have the 3rd generation stab. When I get home tonight I will check the cg and let you know!

Dan
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Old Apr 25, 2010, 03:35 PM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Successful Maiden Flights!

I had a couple of hours to play today. Weather was cooperative, 5-7 mph from the north which allows me to fly in the open space behind my house.

I put the towhook all the way forward as a precaution since the Icon 2 rotates hard and goes vertical with this large center section.

Radio check at 40 paces with reduced Tx output checked OK. Hand toss went well. Elevator neutral setting is very close. Launched on the short start in this wind and it pulled the rubber nicely on the way up and had a good zoom. Yea!

Proceeded to have a 20 minute ride and adjusted the elevator settings for the different flight modes.

Handling was excellent, especially in roll, due to the light tips and the ailerons going all the way to the end. Mixes and throws I gave are a good starting point. I also used my templates to set the different flight modes on these Dreal foils. See pic. The wing is built in the mold in reflex so in speed mode the flaps are in alignment where they are cut out at the middle. Cruise Mode is 2.0 degrees down. Min sink is 6 degrees down. Launch is 10 degrees down. I used some templates that I printed out that I had for the Supra. See Pic.

Second and third flights were similar. At this light wing loading in 5-10 mph wind, the plane would slowly move forward in cruise and penetrate nicely in speed mode. Flew with a couple of hawks for 5 minutes on the last ride.
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Old Apr 25, 2010, 03:42 PM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Some more maiden flight pics..

Pics
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Old Apr 25, 2010, 05:25 PM
They call me Crash!
Kaw1000's Avatar
Ohio
Joined Jun 2006
1,693 Posts
Woo Hoo!! Congrats!! Love the color scheme! Thanks for all the info!

Do you have the templates in pdf form? I sure could use them.
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Old Apr 25, 2010, 05:56 PM
Yep, Naza-controlled Tricopter
tonyestep's Avatar
St. Louis
Joined Apr 2002
1,454 Posts
Jon, do you use dual-rates and/or expo on elevator in different flight modes? I found that I wanted a fair amount of elevator throw (plus snap-flap of course) for dive & zoom, but quite a bit less in cruise and thermal. Is that consistent with what you're finding?
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Old Apr 25, 2010, 06:29 PM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Camber Templates for Drela Airfoils

Dan wrote: "Do you have the templates in pdf form? "

See attachment. For Supra and Icon 2.

Enjoy your Icon 2!

Jon
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Old Apr 26, 2010, 11:03 PM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Quote:
Originally Posted by tonyestep View Post
Jon, do you use dual-rates and/or expo on elevator in different flight modes?"
Yes.

To be Specific: Speed Mode 55% DR Up and Down, Linear
Cruise Mode 75% DR Down, 55% DR Up, 35% Expo
Thermal Mode 70% DR Down, 50% DR Up, 25% Expo

Here 100% is actually no dual rate reduction. A JR thing.

The difference in Up and Down has to do with the extra down I need when landing in either Cruise Mode (most of the time) or Thermal Mode to drive the nose down to the spot when flaps are deployed. The big stab really helps at these slow landing speeds. I don't use a landing mode.

Quote:
Originally Posted by tonyestep View Post
"I found that I wanted a fair amount of elevator throw (plus snap-flap of course) for dive & zoom, but quite a bit less in cruise and thermal. Is that consistent with what you're finding?"
For me I actually dial back the elevator on launch and zoom (DR %55 for both up and down for launch and speed modes. I do use snap flap to help me in these modes though. Makes sense to get the wing and elevator working together. I don't do this in thermal mode as the trailing edge is drooped quite a bit allready and working hard.
IMHO...... I know there are others ideas on this...... This works for me..........
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Old Apr 26, 2010, 11:24 PM
Just an earth-bound misfit, I
Littleton, CO
Joined Feb 2007
300 Posts
Dp?

DP you lurking? Are you coming in May to Denver for both contests?

Any special things you noticed about the Icon 2 and radio settings?

Jon
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Old Apr 27, 2010, 01:28 AM
Yep, Naza-controlled Tricopter
tonyestep's Avatar
St. Louis
Joined Apr 2002
1,454 Posts
Thanks for the info, Jon. Despite the very long time I've had one or another version of the plane, I've actually had only one day of actual set-up flying. Hoping for another day this week.
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Old Apr 27, 2010, 11:34 AM
Daryl Perkins's Avatar
United States, VA, Falls Church
Joined Mar 2007
1,372 Posts
Hey Jon,

Yeah, lurkin' away... ;-) The I2 is a pretty straightforward model. Doesn't seem to require anything special -now that we've got the moments and stab sizes right. I don't run differing pitch throws like you guys in the varying setups - but that's my F3B experience. If I do alter the pitch throw, it's very subtle. I like the model to feel the same through all flight modes. The only real difference in my models through the flight mode regimes are TE settings, rudder coupling amounts and diff settings. And possibly a very slight pitch offset.

And yes, I am coming in May. We can compare models then...

Right now, mine is under 73 ounces, and I have the newest stab on the way that should get about 2 1/2 more ounces out of the model. I'll be bringing that stab for J testing.

D
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