LGM Graphix

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Couple months ago that F4 was being sold as a Bandit haha

invertmast

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LOL... you beat me to it again!

Bob_B

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NOW this IS what RCU is all about, Sharing information that makes the hobby enjoyable.
Great Job Oliver!!!!

vetagator

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Thats the coolest F-4 i have every seen. Its a new series F-4. [sm=72_72.gif] Must of just came out. Who makes it? I like the rounded intakes and the single turbine configuration, saves gas and money. Cool!

David Searles

My Feedback: (49)

WOW!

After all of the negative comments/attacks placed on threads, attempting to impart essentially the same info, regarding individual FEJ aircraft, I am very pleasantly surprised to see this thread remain constructive and positive! Maybe this forum has finally turned a corner!

Well done Oliver!

David S

roger.alli

Great post Oliver.

From what I have read and seen both here and elsewhere, you have a good knowledge of how a well designed model jet should be constructed. These facts should be in the public domain, so please keep them coming.

I personally do not choose to buy Chinese ARFs, (I like to build my planes and pay the extra for BVM), but I understand that they are a fact of life, and now fill a big segment of the market. These ARFs have made the hobby much more accessible, which is a GOOD thing.

I cannot however, understand how a company can release onto the market a product that will definitely fail, when operated as it was designed and manufactured by the factory. Relying on the consumer to fix design flaws is really not acceptable. R&D is the responsibility of the manufacturer, not the consumer.

So, should companies like FEJ be selling untested products into the market? I personally don’t think so. These models are sold as ARFs. Almost Ready to Fly. You should not have to re-engineer major structural components.

A bigger question might be; How will our regulators view an incident involving a model that has crashed, with a known design/construction fault. If there is property damage or personnel injury, there may well be ramifications for all of us.

For this reason alone, I would prefer if untested ARFs (as described in Oliver’s original post), were not on the open market…

(Hope this in not too negative David)


Roger

drdoom

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Just let someone get Killed By any R/C Jet, Especially if it happens in the USA by a US jet... If the jet was made here, They might as well move to China...My .02

Kevin Greene

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Andy, I have some bearing LocTite...It has gap filling qualities and is permanent although a high temp heat gun will loosen it up...I'll get a picture of it tomorrow (11/11/09) afternoon...If you need some I may have a spare bottle laying around...I'll get back to ya tomorrow...

Kevin

Kevin

rbxbear44

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David,
I agree! I pray the "frozen chosen" stay clear and let this thread be as it was started. Always good info from Oliver, Kevin and David.

POWER JET

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Keep up the good work Oliver!!!!!!

Phantoman

My Feedback: (1)

Oliver,

You keep it going. This is the best way to get FEJ to listen up.

THanks for all the help.

Allen

rbxbear44

My Feedback: (86)

I just about finished the build of my F-18F "Bounty Hunter" that replaced the late "Diamond Back" I had before. I can see a marked difference in this newer one versus the other one which was one of the first 10. I feel there is much improvement with airframe weight and gluelines, formers being much straighter. After seeing the inside more closely from the wreckage of my other 18, it seemed more than adequate in structural integrity and would be more than enough for normal flight maneuvers. I lost mine from a flameout, caused by fuel starvation (caved in UAT) and missed the runway by maybe 20 ft. and went into very rough ground. But, as Oliver and others have noted before, the pure inertia of this heavy plane caused considerable damage to the airframe when it hit which I was not surprised of at all. I looked at wing structure, fuse structure, how the fuse joints at the wings and formers faired...and I was impressed! The only part I was a bit surprised at was the very back of the fuse around the vertical fins and Stabs was "egg shelled" but again, I think the inertia had much to do with that.

To say all of this, I have had several flights on the F-18 and with the input from Oliver, David Searles and Kevin Marks and a few others, this is a good airplane and they make good airframes IMO. I assume it is competative enough environment for them to take care of things "under the skin" BY NOW, that what I get in the box is then up to me to add mine and othersbuilding skills to make the package complete! I have had Airworld products with much less structure and was told by them "you Americans don't know how to build planes", expecting us to do things that they have not done.

Saying all of this, I like the FEJ planes. I am not an engineer like Oliver but I was a General Aviation pilot and can understand basic physics and load dynamics BUT I do depend on good threads to help me GET R DUN! These threads are my manual,so to speak. I like James, I like Eric, I like the pricing, I like the fact that while most of our "usual jet suppliers" have not been willing to go BIGGER, these guys have and have proven there is a GIANT JET market out there. I do not like EDF nor the smaller scale stuff.

I just bought the 1/5.5 F-16 in "Artic Aggressor" from my good friend "Whodaman" in CA. Can't wait! I know there are gear issues and wing questions...BUT, I am looking forward to the project and flying their planes.

Rex

David Searles

My Feedback: (49)

Rex,

Glad to hear you got another F-18F. So did I! My original Diamondback is still flying, but showing the wear from the original issues with the gear etc, but the jet flies great, so I got one of the new, improved versions recently, in the AETE scheme. I'll assemble it over the winter and have it ready for spring flying. You will love the F-16. Just make sure it has the new gear upgrade and then only use manual valves like the BVM HiFlow for the retracts and you'll be good to go.

I also built a 1/5 AirWorld F-5 this summer. For what you get and have to do, compared to the FEJ, I'll happily work out the bugs on the FEJ rather than spend the bucks & go thru an Airworld build again!

I'll be flying all of my FEJ aircraft at Buttonwillow next week. F-15, F-16, F-18F & F-100 are all up and RTF, only a few bugs yet to work out on the F-15, but still looking forward to it. I'll try to get some video posted later.

David S

Billy

My Feedback: (15)

Dave , did you get FEJ's new "BIG" F18?? or is it the smaller one.

Thanks,
Billy

AndyAndrews

Ive been using the FEJ 5in1 valve on my Skymaster 1/6th F-16. I took the manual valve I had the screw type and replaced it with 4mm Festo valve. Works fine. I wish they would make the gear lock automatically without the valve but this will work until they do. I forgot to open the valve last weekend on a flight. lol, at least the gear is locked down when that happens ha.

Andy

Andy

David Searles

My Feedback: (49)

Billy,

No this is the 1/7 size. I'm waiting for the 106" F-4. Gonna put twin Rhinos in the Rhino and haul!

David S

yeahbaby

My Feedback: (21)

Dude!!! twin Rhinos in the Rhino. Awesome!!!

they are supposed to have one on display at the AMA convention. take plenty o pix if it shows up

cheers
buck

olnico

Guys, I just had the possibility to review the AT3 recently.

Most of the kit is very well made.
However I have noticed two things:

1) The main formers are made of cheap quality 3 ply plywood. The thickness is 5 mm which would have been fine if the wood was proper aero ply.



2) The wing front and rear spars and wing tube boxes are made of thin balsa with wrong grain once again. Given the weight of the plane and the fact that the main gear is in the wing, it might become a potential problem quite quickly.



Additionally the way the main gear plates have been set up is not optimal. They are just glued on the second and 3rd ribs with no real consideration for the torsion momentum induced in a hard landing.



Given the construction of the wing tube box, there is a risk that the torsion efforts crack the front spars after a while, especially if the plane is used on grass or has a hard landing on concrete.

The grain orientation will make the wing tube box develop horizontal cracks quite rapidly, I would say.

olnico

Here is what I would recommend to do on the AT3 to have a reliable and long lasting structure:

1) Reinforce the rear main former with a small 5 mm plate that is glued and pressed by the wing tube bracket socket head screws ( you'd would have to remove the 4 of them before gluing the plate of course )



2) reinforce the main landing gear area and wing tube box/main spars.

3) put the main gear on flex plates.

olnico

Here is how I would work out the gear area of the wing:

1) Remove the main gear
2) Cut the lower skin around the gear bay to open it up from the front spar to the rear spar and from the wing root rib to the third rib. That would open up a large area and allow you to work out comfortably.



3) Un-glue and remove the gear plates
4) Make a wing root rib reinforcement plate with 4 mm aero ply. This plate should be glued on the inside of the wing and have the opening for the gear strut.
4) Reinforce the area between the first and second rib with a large piece of 200 grs/m2 carbon fiber fabric. It should cover the front and rear spars as well ( U shaped )
5) Reinforce the area between the second and third rib with a large piece of 200 grs/m2 carbon fiber fabric. It should cover the front and rear spars as well ( U shaped )
6) Make a U shaped carbon fiber flex plates with a 2 mm carbon plate and 2 layers of 2 mm aero ply in sandwich. They shall NOT be glued together. The plate shall be running form the third rib up to the wing root rib. Make two square holes in the wing root rib to hold the tips of the flex plate. hold the flex plate from the third rib with two screw and a hard wood block. DO NOT GLUE IT.
7) place hard wood blocks around the gear bay opening to screw the lower skin back ito position.

That would reinforce the wing tube boxes as well as the whole gear area, and offset the torsional efforts into the flex plate...

olnico

Regarding the big F-16, my biggest concern is about the elevator system.

Here is a picture of the brass tube gluing area:



As you can see, the gluing of the elevator frame and load ribs is mostly dry. The whole fuselage section is flexible in this area.
I would strongly recommend every one to open up the speedbrake pods and re-do the brass tube and formers gluing.
I am additionally reinforcing this area of the fuselage with some carbon tapes and rows as well.

I also strongly recommend the owners of this big F-16 do drill the elevator at the rotation tube location and slide/glue in anti-rotation pins, as the gluing method of this tube has been very concerning in the past.

olnico

Chris, what is the takeoff weight of your AT3 ?

SJN

hmm...that is scary stuff [X(]

cairoman

It's still in the box Oly....

I am working on the Nano right now, after which I will start on the AT3, if I will not be able to dump it.

BTW, thanks a lot for the advice.

Chris

cairoman

Well,

It seems that someone is listening at FEJ and whatever Oly has been advising them of, they have fixed (partially at least). I have checked my AT3 and was pleasantly surprised that all the issues mentioned earlier have been dealt with. Even the servo boxes are now made of plywood, not balsa. I wstill don't trust Chinese plywood and will strengthen these with glass cloth.

I will still need to strengthen the main gear mount with some aircraft grade plywood and spread some carbon all around it and also strengthen the main Fuselage former with ply and Carbon. For peace of mind I will also replace all the air rams with UP's and Robarts.

Chris