Flakbait

My Feedback: (20)

Nice job uncle Joe. Really a beutiful bird!!

JPate147

Nice job Unclejoe - it's beautiful.

Paul: I did mount the servo in the wing rib, after gnashing my teeth for a couple of hours with each one figuring out how to do it. . I never thought about the potential for the wing skin to flex. These planes are very thin skinned. That could very well be the problem.

I am building the Vogelsang AT-6 now and it is thinner than the Corsair. The entire fuselage weighs about a pound !

luckyb001

My Feedback: (8)

Here are some photos of my plane, still has alot of rigging to go. Mike

luckyb001

My Feedback: (8)

More

JustJets

My Feedback: (15)

Have been working one one of these for six months.  Have had two Hydraulic pump assemblies fail so far, both seem to work for a while before failing.  Last night after a month of sitting around I decided to do a wing test before a test run on the Motor.  So, as per the instructions I filled the air tank to 80psi, and checked for oil in the system.  When the pump came on line it would not shut off.  Thinking there must be air in the system I cycled the wings up and down several times.  This had no effect, the pump will not shut off when full travel is reached.  If allowed to pump the main pump line ruptures...  Again this system was working fine on initial test, but after a month of bench time things have changed.  Yes, the system was put into long term storage, all air pressure removed from accumulator and the battery was disconnected...  I have lost total confidence in this system...  Has any one had any success with this airplanes folding wing system?  

Side note: My Comp ARF Sales Rep has been very supportive with this reoccurring  problem but is also at a loss.

samparfitt

My Feedback: (43)

justjets,
If I'm 'reading you right', you're putting 80 psi into the accumulator: page 40 of the manual says 3-4 'bar of pressure' which I read as 3-4 psi. I use a hand pump as to not over pressurize the system.
I start with a low pressure, turn on the folding wings system: if the motor doesn't operate, I give a couple of manual 'pumps' until the motor operates.
You also have to insure no air bubbles are in the hydraulic system as I don't think the wings will move (or will move sluggishly).
I found that too much pressure causes the pump to run continuously (which will burn up the motor).

JeffH

My Feedback: (43)

1 bar equals 14.5 psi. Its another way of measuring pressure.

Illusion258

I have a fei bao F-18, or aviation design scorpion I would willing to trade for one these.

They are both RTF

rcwarbirdbuilder

My Feedback: (104)

I thought I had to have one to, but after reading about the airlron flutters and a crash I well wait on this airplane and move to some other project for now.

JustJets

My Feedback: (15)

Hi Sam,
That pressure sounds too low according to the Manufactures recommendations. MTH, the manufacture recommends 8 Bar, a range from 5 to 10 Bar allowable. Keep in mind 1 Bar equals 14.5 PSI. With that said 80 psi is approximately 5.5 bar. I'm glad your system is working and you have peace of mind with it. At this point we must have we different system design... Mine will not shut off at any pressure, High or Low...

Also I run a pressure gage on my pump in PSI, and one in the Plane itself which reads out in Bar, this is a stand alone air-system in that it provides air to the folding wing system only...

Phil

samparfitt

My Feedback: (43)

There's no way that I have that much pressure in mine: I probably have 10 lbs (or less) and mine works at that low pressure. When I put a higher pressure in the system, the motor would 'kick on' every few seconds.
Air in the hydraulic lines would also give you problems.
You're correct on the bar pressure: I just 'googled' it and it says 1 bar = 14.7: possibly, the translation got hosed and it should really say 3-4 psi as a starting point!
Perhaps, other owners will 'chime in' and say what pressure that they are using.
I have no idea how the accumulator works but I'm guessing that a rubber bladder separates the oil from the air and if the oil is not present (or not in a closed loop), a large air pressure may damage the bladder.

JPate147

Hello All,

I had the problem of aileron flutter, and I worked through a fix for it with everyone's help.

I replaced the Hitec 5645 with a JR 8711 but still had the flutter on the next flight. I then moved the aileron servo to a seperate hatch cut into the wing. I built a 'box' of 1/8 hard balsa to stiffen the wing skins, and moved the aileron horn to the outside - ala traditional construction. The slop was reduced, but still present. I just couldn't figure out where the remaining slop was coming from, but then noticed there was a slight movement in the servo arm, even under electrical load. I struggled with this, as the servo has metal gears and is so powerful, but I went ahead and changed it out. That fixed the problem.

The last flight on the 8711 experienced flutter, and that must have weakened the gear train, just enough to introduce a little play. I have ordered two new servo gear sets and will change out the bad gears.

Thanks again for everyones suggestions.

Jerry

docgboy

I use about 100 psi. Anything less and the wings go up to slow. The only problem I have had is if I let the plane sit a while it will lose its prime. If it does the motor will run continuously. Usually moving the wing panel by hand will reprime the system.

The way you need to look at this system is what is the min amount of pressure you need to move your wings at a resonable pace. I have no idea how Sam was moving those wings with 3-4 lbs of pressure, but mine don't move at all untill about 80psi. The value that you set will be the pressure that needs to accumulate to shut the system off. /when the pressure is below that inside the system the motor runs until it reaches an end point and build up pressure.

Scott

JustJets

My Feedback: (15)

It appears that you have a bigger problem than we do...

docgboy

I have no problems the system has been reliable for over a year now and has had over 100 cycles

guido123

Hello JPate147

what you can try is to balance the ailerons with lead in the leading edge. Full scale warbirds always have control surfaces balanced, because tailheavy control surfaces always have a natural tendency to flutter.

Guido123

uncljoe

My Feedback: (8)

Been conversing with owners of the bent wing bird,who have quite a few flights on the F4U,all have said that the key to NOT Getting Flutter is to keep the SPEED down, Fly the Aircraft at a Scale speed . These guys have at least 25 to 40 flights,and none have experienced flutter.I believe even the manual states not to fly too fast. Brian O'Meara lost his F4U due to wing flutter Not Aileron flutter. (these aircraft are or were powered by a Moki 250)
Semper Fi
joe

JPate147

Good advice. I regret not being able to fly with the option of a high speed pass, or even a descending turn without reducing throttle but that beats losing your plane.

wind junkie

My Feedback: (1)

Is flutter an issue with the NON FOLDING wing version also? It seems surprising a full composite wing can't be made stiff enough to withstand full speed passes. I have to believe there is an artifact with the folding wing mechanism that allows flexure.

Comp ARF has plenty of scale aerobats that don't have this problem.

JPate147

My version is the non-folding wing - ARF. It was factory built. The flutter began with the ailerons and I changed the servos out to JR 8711's. The next flight I actually had flutter in the right outboard wing.

uncljoe

My Feedback: (8)

There are Two Folding wing version that I know have yet & I doubt they will have Flutter.
Semper fi
joe

busuttil

Hey Guys,

I have found this build thread very usefull throughout my corsair build.
I only have the folding wing hinge covers to fit on and sort out the wing folding plumbing.

I wonder if you could post photos of how you attached the wing hinge covers as there is not much space were to attach the hinges due to the wing folding mechanism.
Thank you.

Regards,
Brian.

IFLYBVM2

My Feedback: (360)

For the guys who have completed and flown the folding wing version-What is opinion on the folding wing system, ie, is it worth the hassle or if you had it to do over would you opt for the non-folding version ?
Also, it seems the Moki 250 being WAY more power than this bird needs is contributing to the flutter issues. Would restricting the throttle travel to limit RPMs be an option to keep guys out of trouble ? Kinda like a block of wood under the pedal I guess. Also, would the 215 be a better option with it offering a little less power ?
It will be hard to always remember to keep the throttle in check, especially when you want to do a low fly by. Opinions ?
Thanks-Mike Oberst

wind junkie

My Feedback: (1)

Ok, then can I ask the question this way: Does anyone have either wing version and a Moki 250 that does NOT have a flutter issue during a full throttle pass?

I don't have the cash yet, but this dream plane is on my bucket list and I've been watching this tread for a while. As some are saying, needing to limit the throttle really takes away from one of the prime attractions in flying this bird with that radial. The sound during a low pass is amazing even in the videos and I can only imagine what it must be like in person.

mick15

I have been following this thread for some time now and the last thing I want is for you to think I’m gloating but this is typical of CompARF everything seems over complicated just as it was with their Mig.

I have built and am flying a Bates quarter scale Sea Fury, which has hydraulic folding wings and hydraulic landing gear. Now believe me things don’t have to be this complex!

I am attaching a drawing of the oil circuit with regard to the u/c, the wings are controlled with another 5-way distribution valve but utilise the common pump/accumulator.

Therefore I am convinced my system could be made to work on your Corsairs and if so your difficulties would be over.

regards m