gunradd

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here is a pic of the details in the missile bay. It’s not 💯 scale but still a lot better then nothing and gives something to look at when doing static

yeahbaby

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Well done amigo

gunradd

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Thanks B

Weathering is pretty much done. Now to let it dry until Tuesday night before I load it for a Wednesday morning maiden.

more pics. I added 4 missiles into the bottom bay that I had laying around. These are temp but have a good effect on a missile bay open pass at Florida jets.

Before Kentucky I’m thinking about putting dropping bombs into the belly bay like my F15 had.

the little panel behind the cockpit has som small magnets so it’s easy to remove and check UAT.

gunradd

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Had a good time at FLjets. Unfortunately the f22 has rudder flutter on the left rudder and the entire stab came out in flight. I was able to get the plane down but did some damage to her. I spent that night and next day repairing it. Lucky for me I still had the old verticals from the prototype.

so I got her all fixed and flew her 5 times after that. No flutter after I made some changes. When I get more time I’ll go over that.

skunkwurk

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Bummer!

David Jackson

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Wow, that's some scary sh--. Hoping to get info that may help others and myself avoid a catastrophe.

Looping31

Glad you saved it.
Please give us as much detail as you can, we need to know. Mine is almost ready to maiden, but given your probem, I’m now checking the rear fuselage and fins.
Thank you.
Arnaud

skunkwurk

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Gun - is there a video of the flight when the flutter occurred?

Dansy

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I don’t have one but it was quite something to see.....I taught that model was in a much worst condition....

Looping31

Inside the rear fuselage, I added a wood part at the bottom of the fin spar tube and glued some dry assemblies in this area.

Looping31

Also, to prevent flutter, I applied expansive epoxy around the fin spar tubes. And the same on the rudder side.
I solved the free-play issue of the rudder by applying hot glue in the servo drive metal device just before putting rudder in place.
Hope it will be OK.

skunkwurk

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Looks good!

gunradd

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So the issue is the fitting on the left rudder to servo connection. The parts where made slightly undersized creating play. I got the play out by sticking the fitting in a vise and squeezing it in slightly. This worked but in order to have it like that the servo needed to be just on the edge of the fitting because if it went down further is would have the play again. The structure it self is strong on the verticals. Flutter will destroy about anything.

So my recommendations for now.
1. Shim the servo up high so it sits deep into the fitting.
2. Install one or 2 screws into the fitting that you screw the verticals into. they already have 2 holes in them but one might be full of glue.

I am working with the factory to try and get them to make some servo fittings with tighter slots so then the customer will need to file the gap to match their rudder fitting. This seems to be the best option since sending out new rudders would also mean new verticals and the paint will probably not match.

So the flights I had at FLjets where with the old verticals that only have 4 plastic hinges and they did fine. The difference was the pin in the rudder was larger and fit the servo fittings tight and I also shimmed the servo higher into the fitting. The factory is sending new verticals and fittings. So I will see how tight they are when they arrive and undate this thread.

I doubt anyone got video of the first flight. Was not many people around then. The next flight was on video though but no flutter since all that was fixed.

The aircraft flies unbelievable. I did 2 laps and it felt great already. The pass it fluttered I was doing a pass 5 feet off the deck at a decent speed and pulled it into a high G turn staying 5 feet off the deck. About half way through the fin departed.

The AR system is simply unbelievable. This is without a doubt the best flying scale bird I have flown. So much fun to fly.

gunradd

My Feedback: (9)

Her is a pic of the fitting. You can see the pin already left a wear mark on it. That was the flutter.

FenderBean

Not to hijack anyones thunder but if you need more info, I did all the above in my build with videos on it.
My only worry with this setup up is the soft general quality of metals and the aluminum wearing which will result in the same, only time will tell.

Looping31

Thank you for the feedback Gunradd

Len

My Feedback: (3)

Hi Kris,
Have you ever seen or heard about this light controller from T-One in my F-22? I cannot find a thing online and Pacific RC Jets may be closed for a time... Anyway if you have any info I’d sure appreciate it! Thanks,
Len

gunradd

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hello Len!

i have not seen that one before. It’s possible mine is the same but it’s an early version of that.

if it is it’s super simple and simply works. I’ll see what I can find out.

if it’s like the one I have you will need a channel to turn lights on and off or they won’t come on.

Len

My Feedback: (3)

Hi Kris,
I had a servo tester (Tx channel driver) in the ‘switch’ socket and drove it from 100 to 200 but it had no effect. I felt that as normal the controller and the servo driver needed a common ground to be effective but that’s when you can damage the internal parts so I stopped before that. I had 6.6v on the servo channel and 7.4 on the controller’s input power, but still nothing. I did run 7.4v direct to one of the slime lights and it works fine so no joy on the controller at this point. I asked Dirk for info back in the fall, was told a manual for the plane was coming by Xmas, and at that time I was also told to use 12v but never had a sheet on it. I have asked again very recently (like a couple of days ago) with this same photo and have not heard anything yet but that could be COVID-19 related or just not enough time yet... My online search was fruitless too unfortunately. Anyway whatever you can find would be most appreciated. I look forward to the new rudder ‘linkage’ parts too!!!
Thanks Kris,
Len

FenderBean

nvm

ravill

My Feedback: (11)

Hmm, again, I’m thinking moving the rudder servos into the vertical stabs....

FenderBean

Its not that easy, I looked and without an Arm on the current rudder rod it would be more than anyone is going to do. Again here we go with having to do major modification to make a model safe. Not playing this game again, there should be no issue sending a drive unit with 1mm smaller groove cut in it to solve this problem.

Len

My Feedback: (3)

Unfortunately the tighter(est) existing slotted drive will not stop the flutter, but it will reduce it some. That’s all we can ever do with flutter: increase the holding power of both the servo and the linkage and increase the strength of the fins and rudders and their hinging to a level capable of withstanding the speed of the air over the surface. I had this issue in both JL F-22’s and the Der Jet F-35A.

Fortunately I had friends with better hearing than I listening for it and we also knew up front that the JL F-22’s Vne was 170mph. I saw at least 5 of them have fin and/or rudder departures during my 20 years in Hawaii. Luckily mine never did, but Mine only had a Titan SE (160) while some of the other guys had 180’s and 220’s! The DJ F-35A experienced the same rudder flutter issue using an internal coupling for the rudders to maintain a linkage free exterior. It was on an onboard Xicoy GPS that we could plot on Google Earth later and see the flight points and speeds, and flutter occurred at a relatively low speed!

The JL F-22’s had an external linkage but it was designed right at the bottom of the rudder. The JL F-22 fix was to increase the torque on the rudder servo and to move the linkage and hence the servo upwards to enable a mid line for the rudder linkage. No one wants an external rudder linkage, but we desire a crashed plane even less.

To be fair, I have not examined these fins and rudders for this conversion as yet, but I currently see no reason it cannot be done as long as one accepts that it will be much less attractive scale-wise. I will be examining them today though! One other option is to pin the rudders solid (no longer an AMA legal plane)...

On the DJ F-35A, I split the rudders in two at the mid section since I knew the DJ Factory was building a new set of fins and rudders and re-engineering the linkage!!! I solidified the upper half rudders so the lower halves would still function, allowing the plane to still qualify under the AMA regs for turbines. After test flying at moderate speeds and not hearing any sound we tried it at max thrust over an upwind pass and still it was silent. The post flight inspection showed no damage, so we assumed it was ‘fixed’. I flew that plane in Hawaii only a few more times. Then with our winter home move from HI to AZ, I shipped the F-35A back to Canada and have not yet made the time or had the inclination to install the new set of factory fins and rudders...but I inspected their work and it appears well capable of withstanding more than my limited fix on the original design.

Personally I am waiting to see what, if anything, the T-One factory does to combat this flutter issue. The Der Jet factory team was AWESOME and completely re-engineered their rudder linkages internally and made it very strong, and it has withstood the test of time with Dave Wilshire in England as the test pilot.

gunradd

My Feedback: (9)

for the rudders I flew the way it is now many times but I had prototype linkages that where tight and no play. I flew that plane probably at least 40 times and was flying it very hard. So the current setup works it just needs fittings that are properly sized. From what I hear they are going to do my recommendation and give current planes a smaller fitting then we would need to file them to the exact size. To me that should work fine.

I have the demo bird back on the table doing the repairs from Florida jets now. Its flyable but I want her to look new again so she needs some love. The nose was cracked almost off so that's going to be the fun area. Plan on getting her done in the next few weeks and then seeing what the factory plan is. I need to get this bird back in the air so I can be ready for KYjets.

Len

My Feedback: (3)

Sounds great Kris! If they open the borders I may come down for a peek! Dirk says he passed along. My concerns to the factory and will advise their response. I think the easiest thing for me is to disassemble it and see the airline issues. Right now the 4 inputs to the 2 controllers are plumbed to atmosphere so there is an error for certain. I’d like to get a light controller like Keith’s (Fenderbean) and yours as it has a legend and the one they sent me has no documentation at all that I can find. Also Dirk said they are working on the English translation to a comprehensive manual too. Let’s hope the rudder fix will work long term. I still have reservations on any direct to hinge-line driven rudder system as there is no torque arm to support the rudder even though the servo won’t move. It will be fine at least at first, but if there is even a tiny amount of wear that induces any slop, then flutter is likely imminent. Yeah I know too many years doing engineering calculations...a lot can change when things are delved into the real world!!! I hope its good, and your idea of a slightly oversize pin, and we slowly reduce it into a tight ‘fit’, is a perfect way to delve into the real world!
Thanks,
Len