Fly Eagle F-15 (1/9) Building Thread
03-19-2009, 10:04 AM
#401
RE: Fly Eagle F-15 (1/9) Building Thread
ORIGINAL: sskianpour
On another QC note, anybody WITH THE ORIGINAL (IN PRODUCTION A YEAR AGO) , NOT NEW ADVANCED MODEL F-15's had any structural integrity issues regarding cracks in wings? wings splitting in 2 in flight? Bulkheads or formers falling out? Or in general having concerns over structural integrity and airworthiness of their aircraft?
On another QC note, anybody WITH THE ORIGINAL (IN PRODUCTION A YEAR AGO) , NOT NEW ADVANCED MODEL F-15's had any structural integrity issues regarding cracks in wings? wings splitting in 2 in flight? Bulkheads or formers falling out? Or in general having concerns over structural integrity and airworthiness of their aircraft?
I have one of the first 1/9 F-15's to come out of the FEJ factory. I have the exact same problems with the structure in the wings that jimngu reported above ([link=http://www.rcuniverse.com/forum/fb.asp?m=8489647]http://www.rcuniverse.com/forum/fb.asp?m=8489647[/link]). I don't know if his is the older one like mine or if the new one is still having the same problem. On mine, the cracks in the wing ribs has weakened the structure enough that I'm starting to get cracks in the actual wing skin - particularly where I used to pick it up. I now no longer pick the model up by the wings at all - only the fuselage. I have fixed the inner wing ribs that have broken primarily because I could reach them (although I had to cut holes in the root ribs to get in there), but there are breaks in the outer ribs that I can not get too.
As I've mentioned before, I had a JL F-15 and it was much more robust. I am more concerned with the structure of the FEJ F-15 than I was with that one (even the layup in the fuselage of the FEJ F-15 is thinner and weaker than the JL), but I've decided to keep flying the FEJ F-15 and just keep an eye on it.
That, BTW, is what gives me quite a bit of pause in FEJ building all of the big models that they are - although guys who have them keep *insisting* that they are structurally up to the task. Time will tell in all cases...
Bob
03-19-2009, 12:04 PM
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RE: Fly Eagle F-15 (1/9) Building Thread
ORIGINAL: rhklenke
Shaz,
I have one of the first 1/9 F-15's to come out of the FEJ factory. I have the exact same problems with the structure in the wings that jimngu reported above ([link=http://www.rcuniverse.com/forum/fb.asp?m=8489647]http://www.rcuniverse.com/forum/fb.asp?m=8489647[/link]). I don't know if his is the older one like mine or if the new one is still having the same problem. On mine, the cracks in the wing ribs has weakened the structure enough that I'm starting to get cracks in the actual wing skin - particularly where I used to pick it up. I now no longer pick the model up by the wings at all - only the fuselage. I have fixed the inner wing ribs that have broken primarily because I could reach them (although I had to cut holes in the root ribs to get in there), but there are breaks in the outer ribs that I can not get too.
As I've mentioned before, I had a JL F-15 and it was much more robust. I am more concerned with the structure of the FEJ F-15 than I was with that one (even the layup in the fuselage of the FEJ F-15 is thinner and weaker than the JL), but I've decided to keep flying the FEJ F-15 and just keep an eye on it.
That, BTW, is what gives me quite a bit of pause in FEJ building all of the big models that they are - although guys who have them keep *insisting* that they are structurally up to the task. Time will tell in all cases...
Bob
ORIGINAL: sskianpour
On another QC note, anybody WITH THE ORIGINAL (IN PRODUCTION A YEAR AGO) , NOT NEW ADVANCED MODEL F-15's had any structural integrity issues regarding cracks in wings? wings splitting in 2 in flight? Bulkheads or formers falling out? Or in general having concerns over structural integrity and airworthiness of their aircraft?
On another QC note, anybody WITH THE ORIGINAL (IN PRODUCTION A YEAR AGO) , NOT NEW ADVANCED MODEL F-15's had any structural integrity issues regarding cracks in wings? wings splitting in 2 in flight? Bulkheads or formers falling out? Or in general having concerns over structural integrity and airworthiness of their aircraft?
I have one of the first 1/9 F-15's to come out of the FEJ factory. I have the exact same problems with the structure in the wings that jimngu reported above ([link=http://www.rcuniverse.com/forum/fb.asp?m=8489647]http://www.rcuniverse.com/forum/fb.asp?m=8489647[/link]). I don't know if his is the older one like mine or if the new one is still having the same problem. On mine, the cracks in the wing ribs has weakened the structure enough that I'm starting to get cracks in the actual wing skin - particularly where I used to pick it up. I now no longer pick the model up by the wings at all - only the fuselage. I have fixed the inner wing ribs that have broken primarily because I could reach them (although I had to cut holes in the root ribs to get in there), but there are breaks in the outer ribs that I can not get too.
As I've mentioned before, I had a JL F-15 and it was much more robust. I am more concerned with the structure of the FEJ F-15 than I was with that one (even the layup in the fuselage of the FEJ F-15 is thinner and weaker than the JL), but I've decided to keep flying the FEJ F-15 and just keep an eye on it.
That, BTW, is what gives me quite a bit of pause in FEJ building all of the big models that they are - although guys who have them keep *insisting* that they are structurally up to the task. Time will tell in all cases...
Bob
On a practical note, a possible fix where cracked ribs are inaccessible is to use aerosol foam which you squirt into the cavity - you may need to drill a hole to get the applicator tube into the cavity. The foam expands and fills the cavity and then sets. Provided that there is an escape path for the excess foam, the curing process does not lead to a pressure build-up and thence a deformed wing. I have used this fix in several i/c powered models where the thin l/e sheeting has collapsed with handling. The weight penalty is negligible and you are left with a rigid wing - effectively a foam core wing with internal ribs - cracked or otherwise, and wholly sheeted. The foam is marketed in the UK as gap filling foam for builders' use. BTW it is a bugger to clean off and acetone is useful for cleaning off spillage.
03-19-2009, 07:25 PM
#403
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RE: Fly Eagle F-15 (1/9) Building Thread
SPERX I was actually mulling over the idea of foam as a possible solution to reinforcing questionable wing structures. I thought of it the other night when I contemplated the effectiveness of mixing some gorilla glue up and pouring it into the wing (as you may know, the stuff expands, foams up and then turns rock hard with not much weight added). Your idea seems a whole heck of a lot more intelligent.
What is this foam called exactly and where can I order some?
TIA
Shaz
What is this foam called exactly and where can I order some?
TIA
Shaz
03-19-2009, 10:13 PM
#404
RE: Fly Eagle F-15 (1/9) Building Thread
Shaz,
I think he's talking about urethane foam sold at places like Home Despot for sealing gaps in your wall, foundation, etc. I think I might look into that too and see how it works. You do have to be VERY careful with it though, as it expands like crazy and almost nothing can stop it. For a structure like a wing, you'd better fill it in a little at a time and let it harden because if you fill the entire space, even if it has a hole to get out of, it may cure unevenly and the uncured stuff at the bottom will continue to expand. That's OK in a foundation where it will not move the concrete, but in a weak structure like a wing, it will deform it...
Bob
I think he's talking about urethane foam sold at places like Home Despot for sealing gaps in your wall, foundation, etc. I think I might look into that too and see how it works. You do have to be VERY careful with it though, as it expands like crazy and almost nothing can stop it. For a structure like a wing, you'd better fill it in a little at a time and let it harden because if you fill the entire space, even if it has a hole to get out of, it may cure unevenly and the uncured stuff at the bottom will continue to expand. That's OK in a foundation where it will not move the concrete, but in a weak structure like a wing, it will deform it...
Bob
03-19-2009, 10:51 PM
#405
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RE: Fly Eagle F-15 (1/9) Building Thread
Good Idea Bob. Perhaps also not a bad idea to develop a long nozzle for the tip of the foam can kind of like a can of WD-40 has but more flexible. Cheap fuel line would do the trick, that way we can get the line down into the narrow recesses that are hard to reach and go a little squirt at a time like you said. Hmmm...now how to NOT screw this up...I can see myself walking into my workroom with horror on my face the next morning as my wing is split in 2 and foamy goo is oozing out [&:]
03-20-2009, 12:50 AM
#406
RE: Fly Eagle F-15 (1/9) Building Thread
Over the years I've used the expanding foam to fix many wings and always have some in the shop. With my older gassers with foam core wings the smoke fluid and gasoline would eventually seep into the wing and dissolve the foam. It comes with a tube applicator but you can extend it to reach far into the wing. I usually buy the "super expanding" variety but they also sell medium and low expanding versions. It's the same thing as the polyurathane Elmers or Gorilla glue. As a matter of fact, years ago they also advertised it as insulating foam AND/OR glue in one can.
As long as it has somewhere to escape it won't bulge the wing and it foams quickly so it won't have you guessing if you've used too much. Use acetone for cleanup and it CAN get messy. Once you use it you may as well go around the house and fill all the gaps because it will only last a month or two on the shelf if you're lucky.
As long as it has somewhere to escape it won't bulge the wing and it foams quickly so it won't have you guessing if you've used too much. Use acetone for cleanup and it CAN get messy. Once you use it you may as well go around the house and fill all the gaps because it will only last a month or two on the shelf if you're lucky.
03-20-2009, 02:30 AM
#407
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RE: Fly Eagle F-15 (1/9) Building Thread
Yes thats the stuff - it has a variety of Brand Names in the UK - most DIY stores have an own label variant but its all yellow, gooey and soluble in acetone. Bob clarifies my point about an escape path - it is essential that there is a route out of the wing for the excess volume of expanding foam to escape. I also think that the rate of expansion is affected by ambient temperature - the higher the temp the greater the rate of expansion. I have also used this stuff to fill vac-formed nose cones on EDF as well as filling in voids in polystyrene moulded fuselages on EDF models such as gear wells if I have junked the gear and gone for a hand-launch alternative - I fly off grass strips so EDF with gear is a non-starter.
03-20-2009, 12:56 PM
#408
RE: Fly Eagle F-15 (1/9) Building Thread
A big factor in expansion is moisture. The more moisture the more it expands. If you spray a light mist of water in the wing it will expand more.
03-26-2009, 08:54 PM
#409
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RE: Fly Eagle F-15 (1/9) Building Thread
Hey All,
Would people mind chiming in on the eventual CG that everyone agreed upon?
What is the concensus? 170 mm back from LE at Fuse? 180mm? 185mm?
I would rather be obviously a little nose heavy than tail heavy but would a few of you who really wrung this plane out mind telling me what your CGs are?
TIA
Shaz
Would people mind chiming in on the eventual CG that everyone agreed upon?
What is the concensus? 170 mm back from LE at Fuse? 180mm? 185mm?
I would rather be obviously a little nose heavy than tail heavy but would a few of you who really wrung this plane out mind telling me what your CGs are?
TIA
Shaz
03-26-2009, 08:57 PM
#410
My Feedback: (2)
RE: Fly Eagle F-15 (1/9) Building Thread
Hey All,
Would people mind chiming in on the eventual CG that everyone agreed upon?
What is the concensus? 170 mm back from LE at Fuse? 180mm? 185mm?
I would rather be obviously a little nose heavy than tail heavy but would a few of you who really wrung this plane out mind telling me what your CGs are?
TIA
Shaz
Would people mind chiming in on the eventual CG that everyone agreed upon?
What is the concensus? 170 mm back from LE at Fuse? 180mm? 185mm?
I would rather be obviously a little nose heavy than tail heavy but would a few of you who really wrung this plane out mind telling me what your CGs are?
TIA
Shaz
03-27-2009, 11:03 PM
#411
My Feedback: (2)
RE: Fly Eagle F-15 (1/9) Building Thread
Hello again all,
Nobody seemed to have an opinion on the CG. Would people who have successfully flown this plane mind telling me what CG worked best for them?
Around pages 7-9 there are some discussions on it. I know 165mm seemed too nose heavy according to some people, but it doesn't seem like everyone here ever picked up that discussion again. Please people CG? 175mm from LE? 180? 185?
Thanks,
Shaz
Nobody seemed to have an opinion on the CG. Would people who have successfully flown this plane mind telling me what CG worked best for them?
Around pages 7-9 there are some discussions on it. I know 165mm seemed too nose heavy according to some people, but it doesn't seem like everyone here ever picked up that discussion again. Please people CG? 175mm from LE? 180? 185?
Thanks,
Shaz
03-29-2009, 05:17 AM
#412
RE: Fly Eagle F-15 (1/9) Building Thread
Hello,
I think that the good CG is 185 mm on the f15 avandced version.
I have a big problem with the retract gear (scale rotative gear).I must put a big presure (125 psi min) to have a slow retraction;James send me tomorow the main retract parts!
I think that the legs and wheels are too heavy for the cylinders.
I am disapointed by all "air system" (many leaks and retract gear don't work correctly).The weight of the plane is very heavy and the turbine is minimum p120 or p160 to hope flight well.I have the f15 3 month ago and i have always problems!!The price is good but the quality of air system is low;
Fej have a goog comunication after sales but i think that they must upgrade the quality of accessory.
I think that the good CG is 185 mm on the f15 avandced version.
I have a big problem with the retract gear (scale rotative gear).I must put a big presure (125 psi min) to have a slow retraction;James send me tomorow the main retract parts!
I think that the legs and wheels are too heavy for the cylinders.
I am disapointed by all "air system" (many leaks and retract gear don't work correctly).The weight of the plane is very heavy and the turbine is minimum p120 or p160 to hope flight well.I have the f15 3 month ago and i have always problems!!The price is good but the quality of air system is low;
Fej have a goog comunication after sales but i think that they must upgrade the quality of accessory.
03-29-2009, 12:09 PM
#413
RE: Fly Eagle F-15 (1/9) Building Thread
I flew my FEJ F-15 last weekend and for the umteenth time, the main gear did not work correctly. I am now replacing them with Robart units, so I will have NO FEJ air system parts in the jet at all. The total additional cost is now over $700, but the gear will work now. The FEJ landing gear and air system parts are complete JUNK.
Bob
Bob
03-30-2009, 04:22 PM
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RE: Fly Eagle F-15 (1/9) Building Thread
Hey guys i talked to James chen about two weeks ago and he said thet build their air cylinders at there factory now so he said the leaking problem should come to an end, we will see?[8D]
03-30-2009, 04:23 PM
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RE: Fly Eagle F-15 (1/9) Building Thread
Hey guys i talked to James chen about two weeks ago and he said that they build their air cylinders at there factory now so he said the leaking problem should come to an end, we will see?[8D]
03-30-2009, 05:43 PM
#416
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RE: Fly Eagle F-15 (1/9) Building Thread
I spoke to James and he was very nice in sending me 2 new cylinders for my mains however, they also leak (about 10 psi every 10 minutes, which I suppose is not that bad but if that is how bad it is at first, we all know it is a matter of time before they get worse. I have called Shaun at Yellow Aircraft San Diego and sent him a photo of the F15 mains. He believes they are an identical knock-off of the Yellow Gears and believes they have the same exact footprint too. So I ordered for $300 two Yellow Mains complete with cylinders. i will let you all know how they fit. If it is a perfect match, probably not a bad investment...
03-30-2009, 09:53 PM
#417
RE: Fly Eagle F-15 (1/9) Building Thread
Even if the gear don't leak when the cylinders are at rest (i.e., when the gear is up or down), the problem is that they leak while in transit. When this happens, the gear get slowed, or stopped in transit by the airflow after the plane lifts off and the air pressure drops, the gear don't cycle all the way, or get caught on the doors, the air all leaks out, and you're stuck with a gear up landing. I have well over 30 flights on my FEJ F-15 and I can count on one hand the number of times the gear worked correctly in the air - even when they worked perfectly on the ground.
The complete switch to Robarts will solve the problem...
Bob
The complete switch to Robarts will solve the problem...
Bob
03-30-2009, 10:43 PM
#418
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RE: Fly Eagle F-15 (1/9) Building Thread
Good luck with the Robarts Bob. I am hoping the Tam Wheels and Brakes I already have mounted on the original FEJ retracts will transfer over smoothly to the Yellow Retracts. Anybody tried Tam Wheels & Brakes on Yellow Retract gear?
03-31-2009, 11:06 AM
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RE: Fly Eagle F-15 (1/9) Building Thread
ORIGINAL: rhklenke
The complete switch to Robarts will solve the problem...
Bob
The complete switch to Robarts will solve the problem...
Bob
I Finally started the Construction of My F-15 last weekend. So far I changed the Nose Gear steering , I mounted the Servo on the gear trunnion, where the servo moves with the gear. and had a solid set of Push Pull linkages. My cell pix aren't good enough to really see it.
I spent 2 hours trying to get the stab attach horns ball link bolt to NOT rub the fuse. No matter how I installed the crank they rubbed. So I ground off the head of the bolt.
04-02-2009, 06:42 AM
#421
RE: Fly Eagle F-15 (1/9) Building Thread
ORIGINAL: drdoom
What Robart set are you going to use?
What Robart set are you going to use?
Bob
04-02-2009, 07:36 AM
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RE: Fly Eagle F-15 (1/9) Building Thread
ORIGINAL: rhklenke
I've been flying with a Robart 630 nose gear that came off my son's old A10X for awhile now. A friend of mine had a NIB set of 630 main gears that I bought cheap. If I ordered a new set, I'd go with the 635's.
Bob
ORIGINAL: drdoom
What Robart set are you going to use?
What Robart set are you going to use?
Bob
Marty
04-02-2009, 09:07 AM
#423
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RE: Fly Eagle F-15 (1/9) Building Thread
Stay away from return spring. I have them on my falcon 120 and if the tire touches anything, I Know,,, They will not come down.
Phantoman: I made it out of "L" Aluminum Drilled and taped the trunnion and Bolted it to the trunnion. Really the best way the most Positive steering possible. No tangled lines.
My jet doesn't have the servo boxed for the ailerons and flaps. Also Wal-Mart sells a bottle of orange acrylic paint that is a very close match to the orange tiger paint.
Phantoman: I made it out of "L" Aluminum Drilled and taped the trunnion and Bolted it to the trunnion. Really the best way the most Positive steering possible. No tangled lines.
My jet doesn't have the servo boxed for the ailerons and flaps. Also Wal-Mart sells a bottle of orange acrylic paint that is a very close match to the orange tiger paint.
04-08-2009, 09:14 AM
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RE: Fly Eagle F-15 (1/9) Building Thread
Hello,
I am building the F-15 Fly Eagle and I am having some issues with the build. what is the best way to hinge the wings? I see a brief description of how to do this in this thread, but I am still not quite sure the best way to do this. Also, when I build the wooden boxes for the servos in the wings and stabs, the boxes do not fit inside the box. am I supposed to build the box while it is inside the wing? Or do I need to open up the opening a little? It is highly frustrating that there is no manual. It is taking me alot longer to build this plane than I had hoped... Any help would be greatly appreciated. Thanks!
I am building the F-15 Fly Eagle and I am having some issues with the build. what is the best way to hinge the wings? I see a brief description of how to do this in this thread, but I am still not quite sure the best way to do this. Also, when I build the wooden boxes for the servos in the wings and stabs, the boxes do not fit inside the box. am I supposed to build the box while it is inside the wing? Or do I need to open up the opening a little? It is highly frustrating that there is no manual. It is taking me alot longer to build this plane than I had hoped... Any help would be greatly appreciated. Thanks!
04-08-2009, 09:25 AM
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RE: Fly Eagle F-15 (1/9) Building Thread
Hi,
pls have a short look at this... http://www.rcuniverse.com/forum/fb.asp?m=8375300
pls have a short look at this... http://www.rcuniverse.com/forum/fb.asp?m=8375300