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Old Aug 03, 2012, 11:12 AM
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United States, TX, Keller
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Rim,

That wasn't a crash, just a head first slide into second ! Looks like you're getting close.

As soon as I can find a flat field like yours, I'm going to try the Airliner again. Will try with flapperons down. Last time on grass, the retracts grabbed and spun it out. Need a good roll with all the wing loading on this thing.

Good Luck !

Hawk
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Old Aug 03, 2012, 01:06 PM
Chino Renegade oh-gee, yo
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Originally Posted by rimshotcopter View Post
Two Failed Flight test of my Air Hogs Conversion with a V-tail modification. The Second attempt, was more piloting error because I don't recall giving any left stick when the plane rolled right. I do recall giving the plane up elevator and the plane rotated the nose upward for takeoff. After that, things happened so quickly and I don't recall giving it any left stick to counter the right roll. As bad as the crash looks, it is repairable however I have another one waiting and will incorporate lessons learned here. Stay Tuned. ]
Aw man, bummer about the crashes
That was definitely a low speed stall on both accounts...... I would imagine the CG is just a leet-tell rearward from optimum causing her to roll over as one wing stalled. The way her nose immediately lifted off and up before the wing had enough lift makes me wonder about it.
Giving too much up elevator can also cause this (first flight of my old GWS C47 looked much like this, to my surprise) as some planes like just a little up stick to rise off the ground......of course take off speed is needed

Good luck,
--Ray
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Old Aug 03, 2012, 04:35 PM
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Thanks Guys for the words of encouragements. Well, I hope you guys don't mind me using the thread as a (sounding board) but I repaired her and she fights onwards. I know I stated I was going to start in on the new build but I figures to get the best out of the old girl before retiring her.

To help me out here, I am thinking about adding a rate gyro to the Roll and maybe to the Pitch axises just until I get her all trimmed correctly, any opinions?

thank you.
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Old Aug 03, 2012, 08:05 PM
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Originally Posted by rimshotcopter View Post
Thanks Guys for the words of encouragements. Well, I hope you guys don't mind me using the thread as a (sounding board) but I repaired her and she fights onwards. I know I stated I was going to start in on the new build but I figures to get the best out of the old girl before retiring her.

To help me out here, I am thinking about adding a rate gyro to the Roll and maybe to the Pitch axises just until I get her all trimmed correctly, any opinions?

thank you.
Sorry to hear of all the troubles getting her airborne... we've all been there... but it makes it all the better when you do finally get that successful flight.

From the video, it looked like a combination of the following:
- rearward CG
- too much elevator on takeoff
- not enough takeoff speed

I've had models do that before, and it was always one of the above.

Here's my $0.02!!!
CG - Make the airframe as light as possible -- throw the model into some bushes or tall grass. Move the CG forward uintil you get a good glide.

take off speed - How much does your model weigh? From that, you can figure out the wingloading and stall speed. Good info to know so you can stay within the proper flight speed envelope for your model.

Also check how you model sits on the ground. Perhaps raise the front landing gear a bit to ensure air is getting under the wing.

Elevator on Takeoff -- I've been guilty of too much elevator on takeoff A LOT! try putting in a few clicks of up elevator, advance the throttle, and let the model takeoff on its own. Once she is in the air, then throttle up and input up elevator.

Hope this helps... best of luck -- and keep us updated! You'll get her up!
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Old Aug 03, 2012, 08:14 PM
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Wow, thank you SNice, going to give it another go maybe as soon as morning.
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Old Aug 03, 2012, 08:28 PM
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Thank you everyone for your input! Now that I think about it, I am trying to progress to quickly. With that last run, it was the first run that I did not have to apply YAW to keep it running straight and true. I really need to take this in SMALL steps, something that I know I should be doing especially being I am experimenting and have never done this before.

Thanks again!!!
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Old Aug 03, 2012, 11:06 PM
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United States, CA, Corona
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Originally Posted by rimshotcopter View Post
Thanks Guys for the words of encouragements. Well, I hope you guys don't mind me using the thread as a (sounding board) but I repaired her and she fights onwards. I know I stated I was going to start in on the new build but I figures to get the best out of the old girl before retiring her.

To help me out here, I am thinking about adding a rate gyro to the Roll and maybe to the Pitch axises just until I get her all trimmed correctly, any opinions?

thank you.
All you guys are giving good feedbacks! This forum is the place everyone presents and discusses their rc experience.

As I recall, most guys here in this forum reduced the wing dihedral, with various success. Wing dihedral really matters not as much in this Titan, and too much dihedral reduces lift, so does the swept wing layout reduce lift. More lift a wing can generate, takeoff speed will not be as demanding.

Any added weight is not good for flying rc plane.

I am also experimenting a Titan-based flying wing, so far not successful. She accelerated well, but perhaps too much elevator caused her nose up and stall right away.
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Old Aug 04, 2012, 06:42 AM
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Edwen,

It makes sense to me that given a 0 dihedral angle, a swept wing will generate less lift than a straight wing. But the swept wing will create less drag for speed and fuel economy. The F-14 Tomcat and F-111 Aardvark come to mind. On the Titan, seems like the airfoil profile generates a large pressure differential. After all, it's a glider.

-Hawk
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Old Aug 04, 2012, 08:27 AM
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Hawk, so if the idea is to SLOW down the Titan, sweeping the wings straight and removing the dihedral is the solution?

thank you.
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Old Aug 04, 2012, 08:55 AM
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FYI Guys, I like to experiment and try things that have not been done before. I really appreciate all that has been done before. Kudos to one and all!
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Old Aug 04, 2012, 09:25 AM
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Rim,

She does want to glide cause thats what she does and at least for me, she comes in kind of hot. On the puller version, I really had to fly her tall the way to the ground. But what you may want to try is programming flapperons. Deploy them at a good altitude before establishing final. With futaba. I plug the right lead lead into Channel 1 and the left aileron into channel 6 . Activate and trim flapperons on TX . Slows her down nicely.

I've experimented with this on some of my other planes nd it works pretty good.
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Old Aug 04, 2012, 09:30 AM
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Thank you Hawk, I actually have flapperons already, I used a V-tail mixer because I like to keep the transmitter simple because it a cheap CT6. I know and understand the goal is to keep the Titan is light as possible however, I would like to place a camera on it one day and maybe some FPV equipment. So I am trying to increase the load bearing of the wings and the slowness will help with the FPV. I know, I know, I should just get an aircraft that already is proven to work.
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Old Aug 04, 2012, 10:36 AM
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Quote:
Originally Posted by dahawk47 View Post
Edwen,

It makes sense to me that given a 0 dihedral angle, a swept wing will generate less lift than a straight wing. But the swept wing will create less drag for speed and fuel economy. The F-14 Tomcat and F-111 Aardvark come to mind. On the Titan, seems like the airfoil profile generates a large pressure differential. After all, it's a glider.

-Hawk
You are right about the drag with wing swept angle. If the plane is having problem taking off with not enough speed, then less wing sweep would be easier to take off. At takeoff speed, wing drag may not be an issue. At high speed, swept wing would be significantly superior than no wing sweep since lift is no long an issue. Guess the swept wing at least has some advantage for Rim's case: the cg would be backward and makes it easier to adjust as a pusher.

Now I am more convinced about the less dihedral mod for Rim's plane. With V tail, stock dihedral just doesn't seem necessary for stability.
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Old Aug 04, 2012, 10:45 AM
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Now I am more convinced about the less dihedral mod for rimshoot's plane. With V tail, stock dihedral just doesn't seem necessary for stability.
Just came upon this nice little gem.
dihedral is OUT!




http://www.rcgroups.com/forums/showthread.php?t=1197961
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Old Aug 04, 2012, 10:56 AM
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Originally Posted by rimshotcopter View Post
Thank you Hawk, I actually have flapperons already, I used a V-tail mixer because I like to keep the transmitter simple because it a cheap CT6. I know and understand the goal is to keep the Titan is light as possible however, I would like to place a camera on it one day and maybe some FPV equipment. So I am trying to increase the load bearing of the wings and the slowness will help with the FPV. I know, I know, I should just get an aircraft that already is proven to work.
Rim,

If your goal is just to have a stable platform for FPV stuff, you can creat more undercamber by bending down the foam on where normally flap will be installed, or just tape or glue some extra foam pieces there like my Titan trainer. You will probably need to adjust the elevator as the added 'fixed flap" on the stock layout cause the pitch down. I don't need a lot of ground speed to take off this trainer and she is so stable and floats on landing.
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