Working on a F-35 Lightning II
09-06-2011, 11:55 AM
#101
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RE: Working on a F-35 Lightning II
Stig,
Too much elevator I think.
But moving C o G forward and limiting elevator might be bad move.
Good luck.
Pete Powell
PJPJets
Too much elevator I think.
But moving C o G forward and limiting elevator might be bad move.
Good luck.
Pete Powell
PJPJets
09-06-2011, 01:16 PM
#102
RE: Working on a F-35 Lightning II
ORIGINAL: DCM
Just a heads up. Moving the C/G forward will make the model stable,that is the right move. Unless you know exactlly where that point of perfect balance is it is easy to go into the land
of nose heavy. Just make sure you don't reduce too much elevator throw you could need it. As you know the simple act of moving the C/G forward reduces elevator sensitivity.
Its best when testing to adjust one thing at a time then when change is affected you know what changed it.
By the way your doing a super job.
David Hudson
ORIGINAL: Stig Andersen
Thanks Fritz.
I'm planning to move the CG forward by 50 mm (2 inches) and reduce elevator throw. We'll see after the next flight if I am able to cure the problem.
Thanks Fritz.
I'm planning to move the CG forward by 50 mm (2 inches) and reduce elevator throw. We'll see after the next flight if I am able to cure the problem.
Just a heads up. Moving the C/G forward will make the model stable,that is the right move. Unless you know exactlly where that point of perfect balance is it is easy to go into the land
of nose heavy. Just make sure you don't reduce too much elevator throw you could need it. As you know the simple act of moving the C/G forward reduces elevator sensitivity.
Its best when testing to adjust one thing at a time then when change is affected you know what changed it.
By the way your doing a super job.
David Hudson
In any case, if the model was pitch sensitive....fwd CG will help. Now, if the model wanted to dive violently....could be a combination of incorrect elevator trim, perhaps a wing incidence problem?
I hope you figure it out man, I love that model.
David
09-07-2011, 08:52 AM
#104
RE: Working on a F-35 Lightning II
LOL, just finished building a wing servo box!!! At this rate I will finish when my kids are ready for College! 
I'm also sorting out the servo's I need. Looks like I will need Thin Wing servos for rudders, as there really isn't a whole bunch of space in there! I'm usually a Hitec guy, but for the rudders I may need to go the JR High Voltage route.
I also set my eyes on a Rhino in the ads section. We'll see.
I'm also sorting out the servo's I need. Looks like I will need Thin Wing servos for rudders, as there really isn't a whole bunch of space in there! I'm usually a Hitec guy, but for the rudders I may need to go the JR High Voltage route.
I also set my eyes on a Rhino in the ads section. We'll see.
09-07-2011, 09:30 AM
#105
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RE: Working on a F-35 Lightning II
First of all, congrats for the great save. I and many others here measure the pilot skills based on how he reacts in a emergency.
And about the video: The plane took off and right after you eased the elevator it pitched down all the time in the flight. It doesn´t seems to me a cg issue of too much throw in the elevator, but a severe aerodynamic downtrim condition based on wing incidence or elevator.
This picture has a clue.. considering the wing washout, the MAC has a significant down incidence relative to the fuselage and elevators. Quick fix is setting up the elevator with a lot of up trim, but this will let the airplane fly with the fuselage pointing up and it is not pretty.. it would be better to review the wing incidence for a definitive fix.
And about the video: The plane took off and right after you eased the elevator it pitched down all the time in the flight. It doesn´t seems to me a cg issue of too much throw in the elevator, but a severe aerodynamic downtrim condition based on wing incidence or elevator.
This picture has a clue.. considering the wing washout, the MAC has a significant down incidence relative to the fuselage and elevators. Quick fix is setting up the elevator with a lot of up trim, but this will let the airplane fly with the fuselage pointing up and it is not pretty.. it would be better to review the wing incidence for a definitive fix.
09-07-2011, 07:07 PM
#108
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RE: Working on a F-35 Lightning II
Stig,
Good project!!!, and Good save!!!!, I flew the Flyeagle F-35, it did have a high nose attitude during level flight , similar to an F-16, elevators were very sensitive ( effective), the plane was a bit nose heavy, take off was abrupt,
sold the plane early this year, hope this helps....
Good project!!!, and Good save!!!!, I flew the Flyeagle F-35, it did have a high nose attitude during level flight , similar to an F-16, elevators were very sensitive ( effective), the plane was a bit nose heavy, take off was abrupt,
sold the plane early this year, hope this helps....
09-07-2011, 10:31 PM
#109
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RE: Working on a F-35 Lightning II
Thanks for all the input.
I will try to describe the flight in words.
Before the flight I had trimmed a little up elevator on the model as I was under the impression that the model was nose heavy. After rotation I felt that the model was climbing slightly without any input from me, so I pushed the stick slightly forward, and then all h.ll broke loose. The sensitivity of the elevator took me by surprise. After regaining control, I found that the model flew fine without any input on the downwind flight. In the turn the nose pitched up and I struggled to get the model lined up for a landing. I didn't touch the stick much on the landing, but added a little elevator twice toward the end of the flight. The nose pitched up every time I touched the elevator.
I will move the CG forward for the next flight and keep the control throws the same. I will program some dual rate on the elevator and aileron, so I can switch to 50 % throw if the model is still too sentitive. We'll see how it goes this coming saturday, if weather permits. [8D]
I will try to describe the flight in words.
Before the flight I had trimmed a little up elevator on the model as I was under the impression that the model was nose heavy. After rotation I felt that the model was climbing slightly without any input from me, so I pushed the stick slightly forward, and then all h.ll broke loose. The sensitivity of the elevator took me by surprise. After regaining control, I found that the model flew fine without any input on the downwind flight. In the turn the nose pitched up and I struggled to get the model lined up for a landing. I didn't touch the stick much on the landing, but added a little elevator twice toward the end of the flight. The nose pitched up every time I touched the elevator.
I will move the CG forward for the next flight and keep the control throws the same. I will program some dual rate on the elevator and aileron, so I can switch to 50 % throw if the model is still too sentitive. We'll see how it goes this coming saturday, if weather permits. [8D]
09-11-2011, 10:00 AM
#110
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RE: Working on a F-35 Lightning II
I flew the F-35 yesterday. The flight went very well, although there was a nasty cross wind. I switched to 50% throw very shortly after take off and left it there for the rest of the flight. I still need a little more weight in the nose, but overall I'm happy with the flight. I screwed up the landing because of the cross wind and the relativly slow spool up time of my 8 year old SimJet 2300.(Pilot error ) The 35 ended up in the corn field next to the airfield with minor damage to the wings and the nose section of the fuselage. I will fly it again soon after Jepower and hope to do more flights to get the ideal settings for CG and control throws.
Video of the flight was made by Henrik Christiansen and can be seen her: http://www.youtube.com/watch?v=MzaKzfktH9k .
) The 35 ended up in the corn field next to the airfield with minor damage to the wings and the nose section of the fuselage. I will fly it again soon after Jepower and hope to do more flights to get the ideal settings for CG and control throws.Video of the flight was made by Henrik Christiansen and can be seen her: http://www.youtube.com/watch?v=MzaKzfktH9k .
01-08-2013, 11:28 AM
#111
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RE: Working on a F-35 Lightning II
Hi all.
Over the past year I have built a new F-35 from my molds, and finished it with nice paint job and some scale detailing. Here are a few pictures of the finished model from last weekends New Years flying in Beldringe, Denmark. The model didn't fly but hopefully I will be able to maiden it soon.
Btw. The decals are from a Skymaster 1/6th scale F-16. Thanks Anton/John.
Over the past year I have built a new F-35 from my molds, and finished it with nice paint job and some scale detailing. Here are a few pictures of the finished model from last weekends New Years flying in Beldringe, Denmark. The model didn't fly but hopefully I will be able to maiden it soon.
Btw. The decals are from a Skymaster 1/6th scale F-16. Thanks Anton/John.
10-09-2014, 01:14 AM
#113
