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Old Jun 19, 2010, 07:03 AM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
9,053 Posts
Quote:
Originally Posted by trees View Post
I have the launches down. It launches easily at full throttle with a wingtip launch.

I measured back to 9.5" and balanced the plane there. Due to my build it actually came in very nose heavy so I had to add weight to the rear. I'll double-check the CG after I get the motor mount back on.

Hmm, bummer about the 82MGs. I hope they are up to snuff since I bought 6 of them.

Linkages and horns are nice and stiff.

What do you think about my question on the winglets?

"The only thing I can think of other than the plane being too heavy is the angle of the winglets. I measured improperly when cutting the tip angles resulting in a longer slant on the front part of the wingtip. I am horrible at math but I think the angle formed by the slanted wingtip section and the LE is 160 degrees. Could this improper winglet angle be the root of my problems? One other thing I haven't checked is lateral balance but I'm not sure if that would have such a drastic negative effect on handling."

Looking forward to hearing from Chicken Hawk.
The 82MGs are my favorite servos. I have 20+ of them. They may not have enough thrust for that heavy of a plane, especially if you don't set them up to let them use their full movement and leverage it in to the horns. In other words the servo needs to be set up to have it's full rotation and the elevons need to have the right amount of movement. If you program your radio to decrease the throws rather than put smaller horns on the servos you may bind them up.

I don't think your fins are the problem. Can you post a picture? I don't have fins one one of my Reapers and very small fins on the other. The plane without fins does yaw if the speed gets low especially when coming out of a low speed roll but it flies great otherwise. Look at the angle we cut on the Titan and the Assassin and even on one of the Reapers in the pictures and video. I doubt you have the tips angled more than that. Look closely at the front plane in the picture below. I am flying this plane without fins most of the time but I had an extreme angle and small fins being tested when that picture was taken. The plane flies great that way.

Put your plane facing forward and the elevons touching the wall. Use the wall as a straight edge and a square at the wingtips and see if the wingtips are angled out, straight or toed-in in the front of the plane. The plane will fly best if they are toed in about 1/2" and will still fly great if they are angled in a full inch or more. The more they are toed-in the less yaw there will be because there will be more drag at the tips but the increased drag does decrease the glide of the plane slightly.

Let the plane be a little nose heavy and see what happens.

The plane will glide amazing distance and doesn't burn off speed like most planes. The joke is I now need to take a ladder with me to the flying field to get the plane down. We have a couple of beginners flying the Reaper and they have had to learn to do a slow low approach and fly the plane to the ground for landings because it glides so far it can overshoot the runway.
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Last edited by Lee; Jun 19, 2010 at 07:09 AM.
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Old Jun 19, 2010, 11:12 PM
Plane Insane RC.com
chicken hawk's Avatar
Spanish Fork Utah
Joined Mar 2005
1,327 Posts
Shoot, Mine flies great even with the added weight. During my build I took 1inch off of each of the trailing edge of each wing giving it a bit more sweep. My math sucks too so instead of calculating the toe in toe out of the winglets, I just stuck the suckers on. I used the plastic stuff that 3 ring binders are made of. When I was done building I looked at the wing and thought they maybe toed in too far but I few it and it worked great so I left them.
My CG is 10 inches back from the nose.

Oh ya and I'm using Turnigy MG90S metal gear servos in mine and I haven't had a single problem.
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Old Jun 22, 2010, 06:15 AM
Slope Sauce
trees's Avatar
White Salmon WA
Joined Oct 2009
770 Posts
Quote:
Originally Posted by Lee View Post
The 82MGs are my favorite servos. I have 20+ of them. They may not have enough thrust for that heavy of a plane, especially if you don't set them up to let them use their full movement and leverage it in to the horns. In other words the servo needs to be set up to have it's full rotation and the elevons need to have the right amount of movement. If you program your radio to decrease the throws rather than put smaller horns on the servos you may bind them up.
Quote:
Originally Posted by chicken hawk View Post
Oh ya and I'm using Turnigy MG90S metal gear servos in mine and I haven't had a single problem.
If the MG90S are doing fine the 82s should be able to handle the job. If all other adjustments fail to improve my flight I will revisit the servos and make the horn changes/adjustments suggested by Lee.

Quote:
Originally Posted by Lee View Post
I don't think your fins are the problem. Can you post a picture? I don't have fins one one of my Reapers and very small fins on the other. The plane without fins does yaw if the speed gets low especially when coming out of a low speed roll but it flies great otherwise. Look at the angle we cut on the Titan and the Assassin and even on one of the Reapers in the pictures and video. I doubt you have the tips angled more than that. Look closely at the front plane in the picture below. I am flying this plane without fins most of the time but I had an extreme angle and small fins being tested when that picture was taken. The plane flies great that way.

Put your plane facing forward and the elevons touching the wall. Use the wall as a straight edge and a square at the wingtips and see if the wingtips are angled out, straight or toed-in in the front of the plane. The plane will fly best if they are toed in about 1/2" and will still fly great if they are angled in a full inch or more. The more they are toed-in the less yaw there will be because there will be more drag at the tips but the increased drag does decrease the glide of the plane slightly.
I boffed a launch Saturday night and ripped off both winglets. I had a big crowd so I decided to roll with it instead of gluing them back on. In it's current state I'm too nervous to fly it slow so I didn't really notice the difference without the winglets on. In any case, this picture shows the angle of the winglets when they are attached. As you'll see they are drastically toed in.



Quote:
Originally Posted by Lee View Post
Let the plane be a little nose heavy and see what happens.
Quote:
Originally Posted by chicken hawk View Post
My CG is 10 inches back from the nose.
This appears to be conflicting advice but more people have told me to fly nose-heavy so I'll try that first. I'm currently at 9.5 but I'll remove some of my rear weight (my wing came out nose-heavy) and see what happens.

My night flights at Saturday's party were a hit. Everyone was blown away. I'm very much looking forward to getting this baby tuned in and flying as good as it looks. Thanks for your feedback. I'll report back when I've followed some of your advice, done some test flights and received results.
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Old Jun 22, 2010, 06:44 AM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
9,053 Posts
I flew 6 batteries through the Reapers on Saturday and was thinking of the linkages and servos and flying characteristics.

On one of the prototypes I used older full sized Hitec servos because I think I still have about 40 of them. The difference in how the plane behaved was very noticeable. I pulled out some of these servos and was looking at them and one of the old servos weighs more than two of the HS82s, my ESC and my receiver combined. I hate to add that much weight to the plane again. Maybe there is an in-between servo that will work.

I have one of the Reapers with angled fins like yours. The plane flies very well with very little yaw and seems to glide just as well as the straight fin version although this wouldn't be expected.

CG is something I play with on my planes as I tune them in. I had a Scythe that would do incredible snap rolls that really mellowed out with moving the CG forward. I have to choose where to place that CG by the way I want the plane to fly. The Reaper will do the same but it will be slower due to size. When I set up the plane with a forward CG the plane rolls slower and the loops are bigger. As I move the CG back the plane becomes more aerobatic. If I move it back to far it becomes difficult to control and if it is too far back it won't even track but wants to tumble.
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Old Jun 22, 2010, 08:22 AM
Plane Insane RC.com
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Spanish Fork Utah
Joined Mar 2005
1,327 Posts
I used straight fins on mine (as straight as I could without cutting into the wing that is).
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Old Jun 22, 2010, 05:48 PM
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Prop stitches's Avatar
United States, WI, Avoca
Joined Dec 2003
223 Posts
Lee, I got my Scythe kits today, and should have them ready to fly by the next dry day. Will you tell me where the C/G is on this plane? and maybe where I need to mount the electronics.
Thanks for the wonderful planes that you folks design and get out to us in the hinter lands. Please keep them coming.
Gary C
aka Prop stitches
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Old Jun 22, 2010, 08:24 PM
Registered User
Joined Jun 2010
16 Posts
Grim Reaper

Lee, this is one tough wing! Had a servo proplem and had to bring it in before it got away. The GR hit a bike rack hard,tossed out the battery and a sevo but hardly a scratch other wise. The 1st attempt came out heavy 39oz. I'm using a pair of old standard Futaba servo, motor a Super Mega Jet motor,a Neon reciever and a 4000 3cell.It was a bit nose heavy. Going flying in the morning, replaced the battery with a 4cell 1500. Dropped 4oz and put the cg at 9.5" from the nose. I'll let you know how it goes.Dan
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Old Jun 22, 2010, 08:28 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
9,053 Posts
Quote:
Originally Posted by Prop stitches View Post
Lee, I got my Scythe kits today, and should have them ready to fly by the next dry day. Will you tell me where the C/G is on this plane? and maybe where I need to mount the electronics.
Thanks for the wonderful planes that you folks design and get out to us in the hinter lands. Please keep them coming.
Gary C
aka Prop stitches
I have been flying my Scythes a couple of times a week. They are very agile and fun to fly. Post #3 here has the CG info.

http://www.rcgroups.com/forums/showthread.php?t=1204561

Lee
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Old Jun 22, 2010, 08:30 PM
Lee
PERFECT LANDING !!!
Lee's Avatar
USA, UT, Orem
Joined Jul 2004
9,053 Posts
Quote:
Originally Posted by DJJONES View Post
Lee, this is one tough wing! Had a servo proplem and had to bring it in before it got away. The GR hit a bike rack hard,tossed out the battery and a sevo but hardly a scratch other wise. The 1st attempt came out heavy 39oz. I'm using a pair of old standard Futaba servo, motor a Super Mega Jet motor,a Neon reciever and a 4000 3cell.It was a bit nose heavy. Going flying in the morning, replaced the battery with a 4cell 1500. Dropped 4oz and put the cg at 9.5" from the nose. I'll let you know how it goes.Dan
They are tough. Let us know how it goes!!! Your going to love the glide!!
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Old Jun 23, 2010, 11:17 AM
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There was not a cloud in the sky,but hot and winds 10-15 out of the east. The Grim Reaper flew faster and rolled quicker but still not enough up. Going out Friday AM,recharging now.Dan
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Old Jun 23, 2010, 11:31 AM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
9,053 Posts
Quote:
Originally Posted by DJJONES View Post
There was not a cloud in the sky,but hot and winds 10-15 out of the east. The Grim Reaper flew faster and rolled quicker but still not enough up. Going out Friday AM,recharging now.Dan
When you say "up" are you referring to climb (feet per second) or ability to loop?

I do inside and outside loops and fly inverted most every flight with the Reaper and the HS82MG servos. It is all CG, throws and linkages.
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Old Jun 24, 2010, 02:42 AM
Slope Sauce
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White Salmon WA
Joined Oct 2009
770 Posts
I pulled 1.7oz of lead off the rear, glued my winglets back on and brought the Night Reaper out for another night flight tonight. I'm confident there is room for further improvement but the handling was improved significantly on all levels. It was far more trustworthy, stable and I was able to do some satisfying low and relatively slow passes. Yay!
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Old Jun 26, 2010, 08:34 PM
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Joined Jun 2010
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Lee, I ment up as in trim, this time out I added some more up to the evlons.With enough flying time one knows in the first split second if a plane is right or not, the big wing was right this time. I launch with the radio in my left handand the wing with my right at the leading edgeCG,throttle at 3/4,and off it went.Climed to 50' rolled to a spit S and had a great flight! And now I know about the glide!! Im looking forward to many hrs with this wing......What next ?????? bomb drop or wheels..or both ...first more air time .See ya in the air, Dan
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Old Jun 26, 2010, 08:36 PM
Don't disturb the pilot !!!
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Canada, QC, Quebec
Joined Jun 2008
2,187 Posts
One coming to Canada!

Just ordered a GR. Cannot wait to fly this monster with all my FPV gear!!
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Old Jun 30, 2010, 08:56 PM
Plane Insane RC.com
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Spanish Fork Utah
Joined Mar 2005
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Saucisse, I think your going to love it. They make great FPV planes!
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