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2 Post flight questions..
It's a bit difficult to acurately diagnose what I believed to be possible issues with my F-16....Not ever having flown another jet but here' goes anyway.
-The ailerons felt weird, Both Jeff and I thought so, Jeff more importantly having flown 16's for 10 years or so. They seemed to "wander" a bit if that's the right term. Sometimes they would roll faster than others given identical input, If you saw the video, after takeoff halfway through the downwind there were 2 sharp rolls to the right, Those rolls were a result of the same aileron imput I gave later in the flight, Which had much milder re****s. I have 20% expo running 5645's. I don't know if that little bit of slop in the 5645 has anything to do with it, I plan to change them to 5955's anyway. -The stabs are not flush with the speedbrakes, The airplane needed about 10 clicks of up elevator for straight and level flight. The TE of the stabs are roughly 3/8" above the speedbrake. Jeff thinks its slightly nose heavy, CG is at 155mm right now. On that note, If I was willing to live with the CG situation which I probably am because the elevator feels great, How do you think the addition of a pilot would affect things? Thanks! Pete |
RE: 2 Post flight questions..
The up trimmed stab is pretty normal for straight flight on the 16
Check that your ailerons are not drooping any, and both sitting even with the te of the wing at 0 trim. Sometimes if one is drooping a bit, it will want to wander |
RE: 2 Post flight questions..
Thanks Ronnie, I will check that ASAP. Do you think this could be caused by the 5645?
Pete |
RE: 2 Post flight questions..
Sorry, no idea, I never used those
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RE: 2 Post flight questions..
Ok, Just asked because there seems to be a love hate relationship with those servos.
Pete |
RE: 2 Post flight questions..
Add more expo...maybe 35% and or reduce the travel by 10%.
V.. |
RE: 2 Post flight questions..
Strange, very strange. I use 5645's on flaps only, and with the speed dailed down to 50%. They do seem to run a little rough, but I wouldn't expect what you experienced either.
Give it another try with any servo's you have that you know are good. You really don't need much torque at all on ailerons. |
RE: 2 Post flight questions..
Dump the 5645's, they are know for poor centering and spongy feel. Personally, I would never use a hitec servo again... Swap out for a JR 3421 or 9411 and your problem will vanish....
JMO |
RE: 2 Post flight questions..
Ya see, I hear from some that the 5645's are fine, Others say they are paper weights. Im am a Hitec guy so I am going to the 5955's on the ailerons and I'll let you know what happens after capitol jets.
Thanks for the ideas, Pete |
RE: 2 Post flight questions..
What Todd says is pretty accurate i think. Also, usually, f-16s work great with the stab at neutral almost at the bottom of the strake at the leading edge of the stab...Just my .02
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RE: 2 Post flight questions..
ORIGINAL: Pete737 Ya see, I hear from some that the 5645's are fine, Others say they are paper weights. Im am a Hitec guy so I am going to the 5955's on the ailerons and I'll let you know what happens after capitol jets. Thanks for the ideas, Pete Try swapping Hitec for JR and you will no longer be a "Hitec Guy" ;) You dont know what your missing! |
RE: 2 Post flight questions..
ORIGINAL: lov2flyrc ORIGINAL: Pete737 Ya see, I hear from some that the 5645's are fine, Others say they are paper weights. Im am a Hitec guy so I am going to the 5955's on the ailerons and I'll let you know what happens after capitol jets. Thanks for the ideas, Pete Try swapping Hitec for JR and you will no longer be a ''Hitec Guy'' ;) You dont know what your missing! Pete |
RE: 2 Post flight questions..
Wait a minute though.. I forgot all about my TF cessna 310, I have a 5645 on the elevator and that feels fine?? Weird..
Pete |
RE: 2 Post flight questions..
Pete,
I would agree with Todd, the centering could be the issue. I have used DS3421`s in many jets and its a superb servo for that job. I am running them right now on ailerons and rudder in my FB Mig-21, 100flights and counting. My Tams A-4 has 3421`s on every surface and 140flights with no issues, my BVM F-86 the same. V.. |
RE: 2 Post flight questions..
you can only lead a horse to water.....;)
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RE: 2 Post flight questions..
As I recall, Pete has a Futaba radio. Any issues running a JR servo with Futaba? I Think only the connector will be a concern but I'm only guessing since I run only JR in my JR system.
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RE: 2 Post flight questions..
Pete,
I would just swap out the 5645's for the 5955's and it will probably solve your problem. The 5645 is ok for smaller prop 3D and scale models or for something like the flaps where you need some grunt but are not as particular about the centering. I put 7955's in the tail of my Aviation Design F-16 and they seem to work fine. I have JR 8611's in my Boomerang and they work just as well but not any better (at least to me). On the plus side it is so much easier to set up the internal linkages for the elevators using the 7955's that can be programmed. I haven't been into jets all that long so can't comment on how long servos last for this applicaiton. But I can tell you that my 3 year old 35% Wild Hare Sukhoi is on it's original set of 5955's with no failures or gear slop and that I have already had to replace the gears in the JR 8611's in the tail of my 35% Comp Arf Extra due to gear wear after only one year. In the end run I think you are pretty much shooting yourself in the foot if you try to set up something as fast and expensive as a Jet with anything less than the best servo offered by JR, Hitec, Futaba or whoever you feel comfortable with. Just my 2 cents worth. |
RE: 2 Post flight questions..
ORIGINAL: Square Nozzle As I recall, Pete has a Futaba radio. Any issues running a JR servo with Futaba? I Think only the connector will be a concern but I'm only guessing since I run only JR in my JR system. |
RE: 2 Post flight questions..
Well Ive got 2 5955's coming. That should take care of it...
Oh, One more thing, For the maiden my main gear doors didn't close, Both of them hung wide open, So we put the gear back down.. Is there a max operating speed for the gear on a 16? Jeff was well into the flight before we attempted to bring the gear up, Probably doing around 110-120mph or so, Just guessing. Probably close though. Thanks! Pete |
RE: 2 Post flight questions..
Pete,
What F16 do you have? Sorry I might have missed it? I have a FE F 16 and my main doos sometimes stay open after gear up comand. I think this is due to speed at time of gear up and not enough PSI in tank. I find if I slow the jet the doors close and they then stay closed. The leverage point in the first part of ram travel is not much, but once closed the leverage angle changes and it is able to stay closed. Also I fly with a tad of up on the elevator as well. Oh JR 9711's on elevators bought from Todd!! :) the F16 is my first and only scale Jet. I must say I love the way it flies and have no need for any other scale jet! Mav |
RE: 2 Post flight questions..
Hi Mav!
Its a skymaster and I have a slight leak on gear down, Nothing on gear up though. I probably should have topped it off before takeoff, the nose gear door did close though. Next time Ill try it with a higher PSI and pull it up just after lift off. The 16 Is my first jet and happens to be scale but I have an insane need for more :D. Pete |
RE: 2 Post flight questions..
ORIGINAL: Pete737 It's a bit difficult to acurately diagnose what I believed to be possible issues with my F-16....Not ever having flown another jet but here' goes anyway. -The ailerons felt weird, Both Jeff and I thought so, Jeff more importantly having flown 16's for 10 years or so. They seemed to ''wander'' a bit if that's the right term. Sometimes they would roll faster than others given identical input, If you saw the video, after takeoff halfway through the downwind there were 2 sharp rolls to the right, Those rolls were a result of the same aileron imput I gave later in the flight, Which had much milder re****s. I have 20% expo running 5645's. I don't know if that little bit of slop in the 5645 has anything to do with it, I plan to change them to 5955's anyway. -The stabs are not flush with the speedbrakes, The airplane needed about 10 clicks of up elevator for straight and level flight. The TE of the stabs are roughly 3/8'' above the speedbrake. Jeff thinks its slightly nose heavy, CG is at 155mm right now. On that note, If I was willing to live with the CG situation which I probably am because the elevator feels great, How do you think the addition of a pilot would affect things? Thanks! Pete Like you, I am about to maiden my new SM F-16 1/8 after a fatal crash on Aug. 10, 2008. Regarding your question about CG, read this thread: http://www.rcuniverse.com/forum/m_77...tm.htm#8280992 About your ailerons, has you set aileron differential as stated in the manual? Pleas post your maiden flight video Guillermo |
RE: 2 Post flight questions..
Hey Guillermo,
I don't have any aileron differential, I was informed that it was not necessary on the F-16. I did see how the model dives in a steep turn although I did not find it that frighting. Im pretty happy with how it flew other than the roll situation so I think Ill leave it alone for now and get more time on it. Remember though, This was my first turbine flight so take my advise with a grain of salt ;) Heres the vid: Pete [youtube]http://www.youtube.com/watch?v=7fqCJI-MLvY[/youtube] |
RE: 2 Post flight questions..
ORIGINAL: Pete737 Hey Guillermo, I don't have any aileron differential, I was informed that it was not necessary on the F-16. I did see how the model dives in a steep turn although I did not find it that frighting. Im pretty happy with how it flew other than the roll situation so I think Ill leave it alone for now and get more time on it. Remember though, This was my first turbine flight so take my advise with a grain of salt ;) Heres the vid: Pete [youtube]http://www.youtube.com/watch?v=7fqCJI-MLvY[/youtube] Nice video Congratulations Nice Jet and nice flight Hope my maiden will succeed as yours. |
RE: 2 Post flight questions..
I actually trust the tialerons of my TJ F-16 to 5955's and they are really good servos. I used to have JR 9411's but they were not cutting it, so I went for the extra juice of the 5995s. I'm a happy Hi-Tec guy. [8D]
JR is also ok, although you see all these $20K+ models go down and guess which servo brand the pilots where using. ;) |
RE: 2 Post flight questions..
Hey Pete,
First off congrats on a nice maiden. Your servos are not the issue with the roll. The issue lies in the fact the gear remained down the entire flight. Once you get the gear up and the doors close you bring the real aerodynamics into play with the Viper. The wings don't give the lift like a normal bird, the fuselage is responsible for better than 58% of the lift on the Viper. Now keep in mind the gear doors were open, acting like two big holes in your wing, each catching air and causing a change in lift. Retract the gear and the roll issue will go away; I promise. Also the stab trailing edges will will end up above the speedbrakes if the model outline is correct and the CG is close. Real Vipers are the same way. Suck up the gear and enjoy the ride!! Your Hitecs will work fine for you. I do believe you would love the feel of 8611a's back there on the flaperons and stabs, but what you have will work without issue. |
RE: 2 Post flight questions..
Pete, use some expo and double check your ailerons to make sure nothing is binding ... either the linkage or the control surface. I had this same situation a while back and it turns out the control surface, which was live hinged, was catching on the gap cover occasionally. This is probably not the issue, but you should eliminate it as a potential cause.
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RE: 2 Post flight questions..
ORIGINAL: John Redman Hey Pete, First off congrats on a nice maiden. Your servos are not the issue with the roll. The issue lies in the fact the gear remained down the entire flight. Nice catch! That has got to be it. They are pigs with the gear down!!! |
RE: 2 Post flight questions..
Hey Keith, I did check, the ailerons are not binding. The live hinging was catching but I took care of that a while back. Ive got 20% expo.
So it was the gear, Wow, I never would have guessed. Thanks! Pete |
RE: 2 Post flight questions..
Fine job pete...congrats...smooth landing. Like John said, clean her up and see how she goes then. I have owned 7 F-16`s over the many years in the hobby and they all flew crappy with the gear down.
V.. |
RE: 2 Post flight questions..
ORIGINAL: Vincent Fine job pete...congrats...smooth landing. Like John said, clean her up and see how she goes then. I have owned 7 F-16`s over the many years in the hobby and they all flew crappy with the gear down. V.. |
RE: 2 Post flight questions..
Hi Pete,
Got to agree with John. The differance in handeling between an aircraft with gear down, and gear up is night and day. Especially a high performance jet which at speed, will put very high loads on doors etc. ... I follow full size pratice and clean up the gear as soon as the model breaks ground. That way the aerodynamic loads are at minimum, and should the worst happen and you loose an engine on climb out, the aircraft is nice and clean for the best glide angle. There is no real reason to have the gear down at any stage of a flight, unless you are in the landing pattern, or showing off to the judges. Enjoy it. Roger |
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