FEJ 1/7 F-18.....need some help!?
04-13-2014, 02:58 AM
#26
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Pretty much the same as Davids on throws. I kept flaps at no more than 20% degrees on landings. I probably could have done some more but I found "the sweet spot" for landings right there at those flap settings and stayed with them. Keeping final short really helped a lot, along with the Flap settings, I just had it down perfect! I too, had the heavy FG airframes but, as much as they were heavy on the ground, they sure felt light and flew great in the air! I did use a Tam pipe though!!! A BIG and important point in my opinion!!! The pipes, especially bi-furcated ones...Tam is the best for these and well worth the added expense...but it sounds like you are doing a twin setup, so no matter on that.
I never really needed to mix Stab since my flap settings weren't as aggressive as David's. The positive AOA for takeoff is a MUST though!!!
Fender...sending you more pics of the build today. Progressing in "steady eddie" pace. Was in Africa for two weeks on mission, but now home.
Rex
I never really needed to mix Stab since my flap settings weren't as aggressive as David's. The positive AOA for takeoff is a MUST though!!!
Fender...sending you more pics of the build today. Progressing in "steady eddie" pace. Was in Africa for two weeks on mission, but now home.
Rex
04-13-2014, 06:30 AM
#27
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A Tam pipe is a must if it's a single. I put the fej pipe in at first and did some engine runs and taxi tests. When I put the Tam pipe in it was noticeably cooler and had more power.
I also had the main gear mod parts that gave the mains a wider stance. And a gyro on the nose gear also helped with tracking. I had a few other mods involving the gear and doors.
As far as elevator flutter goes, from our vantage point we could not see it happening. I'm going by what I felt while flying.
Marc, I hope you have better luck with yours. If i can help in any way i certainly will. pm me
I also had the main gear mod parts that gave the mains a wider stance. And a gyro on the nose gear also helped with tracking. I had a few other mods involving the gear and doors.
As far as elevator flutter goes, from our vantage point we could not see it happening. I'm going by what I felt while flying.
Marc, I hope you have better luck with yours. If i can help in any way i certainly will. pm me
04-13-2014, 11:06 AM
#28
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Did anyone ever open up a stab to see if the anti rotation pins are housed in balsa or hardwood on the older models.
I checked mine with a bore scope and it looks like balsa but it possible that there is hardwood behind it, if its just balsa i'm going to open it up and replace it.
I checked mine with a bore scope and it looks like balsa but it possible that there is hardwood behind it, if its just balsa i'm going to open it up and replace it.
04-13-2014, 11:17 AM
#29
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I'm not sure if any had issues with the stabs on the old models. If you search the old threads it had gear leaking issuses and a few more other issues but it flew great. My f18 flew good, lost due to power/signal loss.
05-10-2014, 04:51 AM
#32
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I had two of the older ones and never had a single issue with a stab or the pivots. One was eventually lost from a flame out that couldn't get the airframe back to a reasonable flat spot to set it down. The second one had two more years of flights after I sold it and he flew it very aggressive with a P-200 in it. His died from a take off issue on steering...right into a fence!
At that point, no one was worried about the stabs since these planes were so heavy and you couldn't push the skin of the stab in at all with any pressure!
At that point, no one was worried about the stabs since these planes were so heavy and you couldn't push the skin of the stab in at all with any pressure!
05-10-2014, 05:16 AM
#34
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Last edited by Paul Turbine Jet Man; 05-10-2014 at 05:22 AM.
05-10-2014, 06:41 AM
#35
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ditto...ALWAYS balance the stabs! It does help the servo load, especially if you end up with a harder landing! I always balance them with just a bit of load toward the leading edge to keep the servo(s) from "bouncing" to find center while on the ground. Once you get some air/load over the surfaces, the bounce goes away but I go about 1.5oz's heavier (including the epoxy to adhere the weight) to get the stab to load towards the leading edge.
Rex
Rex
05-10-2014, 10:08 AM
#37
My advice would be to remove everything from the plane and hang it from the ceiling.
One year ago I was in the same position as you. I set mine per instructions, as limited as they are.
Also seemed advice from fej. That was limited as well.
If you're going to fly it anyway, go without the flaps. That's where mine went south.
Some people get replacement airplanes, if they know the right people. I emailed James after my crash, not looking for another plane but
at least an answer as to what may have happened. His answer basically said " we fly, sometimes we crash. Happy Easter Day".
Good luck.
One year ago I was in the same position as you. I set mine per instructions, as limited as they are.
Also seemed advice from fej. That was limited as well.
If you're going to fly it anyway, go without the flaps. That's where mine went south.
Some people get replacement airplanes, if they know the right people. I emailed James after my crash, not looking for another plane but
at least an answer as to what may have happened. His answer basically said " we fly, sometimes we crash. Happy Easter Day".
Good luck.
Idiocracy has checked in on the thread.
Here is a BRAND NEW F-16 of the "old" kind that I cut into the stab mechanism to investigate. Maybe there was a critical glue and wood shortage in China back then?
Do yourself a favor and save all your precious equipment you have in your jet.
I know I can't afford to burn stuff ad infinitum.
05-10-2014, 10:40 AM
#38
My Feedback: (28)
Looks like my "chip" is just a little smaller than Randy's.
Nice effort to cover.
05-11-2014, 12:31 AM
#42
W T F is the "ruling" class of RCU? Do you really want to make personal attacks about a guy who came from humble beginnings, paid his way through college, and did something with his life???
Last edited by dubd; 05-11-2014 at 08:19 AM.
05-11-2014, 01:33 AM
#43
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The 1/6 version is considerably bigger and I'm only running two merlin 100'S which produce nearly 11 kg of thrust each ( 22 KG) . Whilst it is not what you would call overpowered... but it is most definitely enough to fly around, climb aggressively and use as a fun jet. Being a twin it has good thrust and I don't loose thrust through a terrible Y pipe.
Also you must have some serious nose weight to balance that jet. I would recommend using a single jet cat 160 and buying a tam jet Y pipe. Save a heap of weight from the engines and nose weight up the front.
Last edited by Paul Turbine Jet Man; 05-11-2014 at 02:08 AM.
05-11-2014, 02:27 AM
#44
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Something else I would recommend is putting some Teflon material between the elevator and side of the aircraft. This removes all lateral play and actually supports the elevator when it moves up and down. I put this modification on my 1/6 , mass balanced the elevators and it’s been flying very nicely. Being Teflon it also provides very little restriction / drag.
BUT the biggest modification I would highly recommend getting rid of the original elevator clamp system…… It’s crap. I custom-made billet aluminium extra-long control clamps 300% longer that gives me considerably more torque and it allows me to use 100 % servo travel from my 40 kg servos see pic) . Most people wonder why they get flutter when they use a BIG powerful servo and then dial it down to 30 – 40 % in their servo travel because it moves too far !!!!! That is just throwing away torque ,holding power and servo resolution. In my opinion this is probably one of the major causes of the beginning of flutter. The servo can’t cope with this enormous flying stab because it is mechanically disadvantaged through the linkage setup. Then inevitably those little tiny undersized pins in the elevator twist and let go……….. Don’t get me wrong I believe there elevator pin set up inside the elevator(as seen on the x-rays) is inadequate. However if any linkage mechanism between the servo and a full flying surface is done badly enough / mechanically disadvantaged….. I don’t think it matters how the elevator is built or which brand…………. flutter will destroy a flying surface in seconds.
Another thing I would do is make your own carbon fiber control surface tabs. I used twin plates so that the control linkages is supported either side and I also set them further back into the surface for the flaps. This provides the flap with more support and mechanical advantage in my opinion. I also line the inside surface of the wing with carbon fibre cloth and plywood to increase its rigidity. This is important as the servo is only as strong as the material it is attached to. I have used full flap as seen in the picture on my jet on most landings and it comes in like a kitten with heaps of lift and drag under power. However I do have flaps on a slider switch which I progressively pull on more and more flap as the aircraft slows down. I strongly disagree with having a flap on a switch that aggressively throws down large degrees of flap with the flick of a switch.
I’ve done the same thing with my big 3m FEJ F16 and A10. Mass balanced the elevators / custom-made linkages, proper servo installation.
Fly Eagle jet builds some nice looking jets but there engineering and mechanical understanding in most areas is very poor. You can get away with a lot of this in small jets but the really big ones 2.6m + just can’t cope in a lot of areas without modification. If you can overcome these issues and redesign them you will have safe flying aircraft……….. That being said now that I can afford the nicer things I will be buying sky master or tomahawk from now on.
BUT the biggest modification I would highly recommend getting rid of the original elevator clamp system…… It’s crap. I custom-made billet aluminium extra-long control clamps 300% longer that gives me considerably more torque and it allows me to use 100 % servo travel from my 40 kg servos see pic) . Most people wonder why they get flutter when they use a BIG powerful servo and then dial it down to 30 – 40 % in their servo travel because it moves too far !!!!! That is just throwing away torque ,holding power and servo resolution. In my opinion this is probably one of the major causes of the beginning of flutter. The servo can’t cope with this enormous flying stab because it is mechanically disadvantaged through the linkage setup. Then inevitably those little tiny undersized pins in the elevator twist and let go……….. Don’t get me wrong I believe there elevator pin set up inside the elevator(as seen on the x-rays) is inadequate. However if any linkage mechanism between the servo and a full flying surface is done badly enough / mechanically disadvantaged….. I don’t think it matters how the elevator is built or which brand…………. flutter will destroy a flying surface in seconds.
Another thing I would do is make your own carbon fiber control surface tabs. I used twin plates so that the control linkages is supported either side and I also set them further back into the surface for the flaps. This provides the flap with more support and mechanical advantage in my opinion. I also line the inside surface of the wing with carbon fibre cloth and plywood to increase its rigidity. This is important as the servo is only as strong as the material it is attached to. I have used full flap as seen in the picture on my jet on most landings and it comes in like a kitten with heaps of lift and drag under power. However I do have flaps on a slider switch which I progressively pull on more and more flap as the aircraft slows down. I strongly disagree with having a flap on a switch that aggressively throws down large degrees of flap with the flick of a switch.
I’ve done the same thing with my big 3m FEJ F16 and A10. Mass balanced the elevators / custom-made linkages, proper servo installation.
Fly Eagle jet builds some nice looking jets but there engineering and mechanical understanding in most areas is very poor. You can get away with a lot of this in small jets but the really big ones 2.6m + just can’t cope in a lot of areas without modification. If you can overcome these issues and redesign them you will have safe flying aircraft……….. That being said now that I can afford the nicer things I will be buying sky master or tomahawk from now on.
05-11-2014, 06:30 AM
#45
Thanks for all the tips will use them in my build ,I have the older fiber glass version 1:6 scale and is heavy that's why I was thinking about the p-160 for power I have the the older p-180 but no y pipe ,I'm going to extend the arms for the elevators using two aluminum extension . Do you using one servo for the elevator or just one? I have the two servos mechanism and if the arms not perfect the servos fight on bigger angles .
11-12-2014, 11:35 AM
#46
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I have an old fiberglass one and its years old now i have moved the c/g to 190mm and its so nice to fly.Took it flying last month a and as soon as it landed we put more fuel in and went again it ways a tone and i have a tams pipe in it with a merlin 160 .Had afew retract and gear door problems at first but now sorted i coud go to the plane tomorrow and put air in it and fly with no problems
love this plane
love this plane
11-12-2014, 03:18 PM
#48
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