David Jackson

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Jack,
Did you maiden your F-16? If so, would appreciate your comments on the handling characteristics of the JL Falcon , specifically as it relates to take-off, slow speed handling, high speed performance provided by the P-180, and landing.

Thanks

mikedenilin

My Feedback: (67)

Hi Jorg,

I ordered mine about the same time in December 2008. They had shipped mine to my club facility in China last weekend. I am now in China for my business projects, so I am able to get in touch with Mr. Yang quite easily. I even talked to him one hour before the big earthquake hit. Both of us survived. And his factory is OK and received no damages! He has no excuse not to produce the planes for us. I speak Chinese so communication is very easy. He told me that it's very time consuming for him to write a good email and there are tons of emails that he needs to reply so he rather tried to get things fixed then just ship the products when he believes they are reliable enough.

The biggest challenge they have is to make their landing gears more reliable. I would rather wait for a set of nice, reliability L/G than get a bad one in a rush.

About the paint scheme, I am gonna roll a dice and decide. I love all these paint schemes, Can't decide on which one.

I will try a couple of these for our club members and Just pick one of them for myself

Mike
Global Jet Club

gooseF22

the desert dress is the most visible. Ive flown the real scale paint jobs and the blue cammo is hard to see. The tigre scheme will blend in the air.

Here is one I like too

sweetpea01

My Feedback: (10)

In CA the desert scheme won't be that easy to see against the mountains. Blue camo is the hardest to see against clouds and blue sky. The artic scheme is also hard to see The grey/white/black blends in better than you think. Guess that is why they are considered Camo

RCISFUN

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Capt Crackers (Thumbnstick's) JL F-16 before its maiden flight at Titusville PA Airport (home of the OC-Turbofest).

RCISFUN

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More...

mikedenilin

My Feedback: (67)

Hi Goose you are right about that.

The place I would be flying at is foggy in the morning, so the Arctic one is not going to cut it. I might go with the more controversial color paint scheme that I did for my 1/8 Scale JL f-16 too.

Mike

David Jackson

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Any comments regarding the handling characteristics, specifically, slow speed, take off, and landing? What powerplant are you using?

thumbnstick

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Well it's been over a week since the first flight. Here is what happened. She went down the runway straight as an arrow. Lifted off with about 50% up elev. CG was on the plans and seemed OK. I turned away after take off and it was great, all controls seemed fine. Went downwind and truned slightly toward me when we saw the vertical fin wave and flutter wildly. I pulled the power off and set up ito a landing pattern. My mind was going a thougsand miles an hour, with now time to consider anything else but to get her back down. The power off soon reduced the flutter ( the fin is fluttering, not the rudder as far as we can see). I pulled the nose slightly and the nose came up, but the aircraft did not climb,,,,,, good, I added a little power and pulled the nose some more while turning it onto base. The nose was up good and I got to at least 50% power before I noticed any decrease in sink rate or speed. Awesome...... it was plowing nose high and power on and SLOWING itself. If I had not grwon up with Byron F-16's, I would have not had the experience to do this. If the fin was not flailing in the wind, I would not have had the gnochies to do it either! The aircraft came onto final working the throttle from 25 to 50% and 20 to 30 degrees nose high. Awesome! This baby landed 30 degrees nose high and less than 40mph. The base of the main wheels axle assembly came off of the strut and did damage to the strut. (I will give a fix for this in a later posting.
The facts and the failures. The fin is attached to the fuse with the same double carbon fiber spar as the wings. (JL and Mr Yang still are strong believers in this system). 1. The rudder servo had stripped gears (Fut 9204). 2. The outer spar to the fin failed, it broke above the mounting joint, and seperated into two pieces, the outer cf tube was loose from the inner cf tube. 3. The front spar ( aluminum rod ) remained in tact. 4. The inner tube "bent and split" instead of breaking in two. Thank God!
Here is the conclusion of JL's and my findings on the fin failure. 1. The spar did not have a good glue joint in the critical area. 2. The fin has very little stress on it in the flight conditions that is had, so it needed something else to make it break. I am 100% sure I did not over tighten it or see any stress on it from shipping or pre-flight assemblies. There had to be rudder flutter ahead of the fin spar failure to make it break. Had to be! The wings are the same spars and 100 times more stress on them. They did not fail.
So like most failures, there most likely was a series of conditions that occured. JL is getting me the needed parts post haste. Mr Yang has been corresponding with me fine. I am satisfied.
Now for what to do in the future. Why would I have a warm a fussy feeling about the double CF spar system. On the positive side, JL is not alone in using the system and type of material, and there are hundred of non-failures. On the negative side, one failure (especially mine LOL ) is too many. Here is what I am doing to any CF tube Jet that I will fly. The inner diameter is slightly larger than .375 " ( about .382"). I purchased the best alluminum .375" solid rod I could. These double spars are approx 7" long. Hysol is used to glue them into the existing spar. I rough grit sanded the aluminum and gently got a mild sanding int the interior of the spar. A .25" rod was used to apply the epoxy into the spar. Lightly coat the .25" with epoxy and keep it turning and moving as you slowly move it into the spar. When you remove the stick, you should see an even coat on it, indicating an even coat alo in the spar, next put a thin coat of hysol on the rod to insert. Take your time and turn it alot as you insert it. This will keep the glue moving and filling the slight gap between the two.
Also a new and higher torque servo is going in the rudder.
I would recommend this to ANY Mfg that uses the double CF spar system. Hope this report gives a solution. I will report on the next flight. Hope to debut this at the OC Turbo Fest in Titusville, Pa on June 21st.

XCaliber

My Feedback: (104)

Thank you for posting your 1st flight experience, sorry about your incident and glad you got it back.
When I noticed how the rudder was to be installed without any type of bearing to secure it to the fin I had a funny filling that it would fail.
So, I managed to install a bearing with aeropoxy on the base of the fin so that the rudder aluminum rod would not have any type of side movement and it is solid with a JR 8611. I am also going to install aluminum rods on all c/f rods.
Please post pictures of the failed rudder & fin and also the landing gear axle that you talked about.
Thanks again,
Mario

thumbnstick

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Your right about that bearing thing on the rudder. I am going to do that on the new one too!
I'll post more stuff latter this week.
Jack

F106A

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The JL L-39 thread has described the failure of the tube spars that JL uses.
http://www.rcuniverse.com/forum/m_63...30/key_/tm.htm
Unfortunately, it was the main spar that broke resulting in a total loss of the aircraft, engine, etc.
After reading the thread, I've got a JL L-39, and this recent post about the F-16, I can't understand why JL continues to use this system instead of solid c/f rods like SM uses.
BRG,
Jon

David Jackson

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After hearing about the issue with your F-16, I plan to insert a 3/8" diameter solid carbon fibre rod in the fin and wing tubes of my plane. I will also install a bearing for the rudder torque rod. I hope these modifications will help. Thanks for the post.

Just wondering, has anyone considered permanently gluing the fin to the fuse?

thumbnstick

My Feedback: (169)

To answer the question about JL changing the design. Mr Yang feels the design is good, but will personally monitor the glueing of the two spars together in all the kits. That's all I can say about that. At least inserting the solid rods makes us feel better about it anyway. The bearing is a good upgrade too. I had some K&S brass tube that will do the trick perfectly.
Jack Graham

XCaliber

My Feedback: (104)

I don't think it's necessary gluing the fin to the fuse.
By doing the rod & bearing mod, securing all hardwear and a very high torque metal gear servo like the JR8611 servo will do the trick.
XCaliber

thumbnstick

My Feedback: (169)

I agree that glueing the fin on is not necessary. In my case, I can not fit the plane in my van with the fin on. So I do perfer the removable fin.
Hopefully the parts will show up soon and I can report on many favorable flights.

mikedenilin

My Feedback: (67)

Hi David, can you please show me where i can get the 'bearing' for the rudder torque rod?

Mike

RCISFUN

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Here is a photo of the broken upper landing gear assy on Jacks F-16

David Jackson

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My plan is to use a brass tube with a diameter large enough to slide onto the rudder torque rod. I will then use either Hysol or epoxy to secure it in place.

David Jackson

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Jack,

I am in the process of making some modifications to the fin and the wing tubes. Can you provide a bit more information regarding the issue with the main gear axle? I hope to maiden my plane by the June 14th, but would like to address all areas of this plane that you have found to be possible points of failure.

Thanks,
dlj

David Jackson

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moderator, please delete

thumbnstick

My Feedback: (169)

The failure on the part that RC is Fun shows is because the static strut loosened from the main strut assembly and put a rearward bending force on the main strut. The strut is not designed to bend backward, something has to give when all the struts are not attached. Just check all the set screws and lock tite them. Do braking test and taxi test. If you go through hard taxi and brake test manuvers, you should be fine. I do not think a Mod is necessary on this part. By the way, set the brake levals low, they lockup and you will flat spot the tires easily. The brakes work too good if anything. Nice brake design, straight and true, lockup in tandum with no side sway. Best handling ground jet I have had.
I'll be flying this baby this weekend at OC TurboFest this weekend. Check out that forum for updates and Pics.
Jack

David Jackson

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Thumbnstick,

Are you using the P-180 for power? If so, are you using the pipe that came with the kit? I am going to use an engine with the same power output as the 180 on my 16, and wanted to make sure the diameter of the pipe was adequate.

XCaliber

My Feedback: (104)

Finally the maiden flight today!!! Thanks to Marvin A. who did the honors & trimed it out for me. All went outstanding. No flutter what so ever on control surfices, couple of left trim clicks on the JR12X. C.G. between J/L & S/M recommendations. Landed at no more than 25mph nose high.
35-37Lbs dry. 43Lbs wet.
JetCat Titan SE, no need for more weight. Power was there. Now to send in my Titan for a check up as it's giving me more failed starts than I can handel[:@]
Thanks Jack for your tips.
Mario

David Jackson

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Did not get to maiden my JL 1/6 scale F-16 at Jets Over Kentucky due to an ecu problem. Glad to hear that your flight went well. I would appreciate any information you can provide on the control surface throws used for the maiden flight. Since there was no information with the plane regarding control surface set-up, I chose to use the set-up provided with the Skymaster 1/6 scale F-16. If all goes well, I hope to maiden the plane by the 12th and have it ready for Cincinnati.