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Old Nov 21, 2012, 05:21 PM
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Ontario, Canada
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EFlite 60-120 retract issue

'Lo all...I've got a problem I'm scratching my head on and can't seem to figure it out...
I've got a set of 60-120 eflite 90 degree retracts installed on a H9 P47 60size...using a 6v Nimh to power the rx and retracts both...
Both units retract into the fuse fine, but the issue is when I hit the switch for them to come down, 1 of them stays up. Quite a rush when you discover this on final approach. I managed to get both down by going inverted and toggling the gear again as I heard that sometimes does the trick. It did thankfully...
I got it in and tested again on the bench, sure enough both retract fine, but 1 of them sticks coming down. When I toggle it on the bench a small tap will indeed let it come down with no issue. I've checked for binding everywhere and nothing seems to be grabbing anywhere, the wheel is completely clear of the well when retracted as well.
Now the funny thing is, when I invert the plane on the work bench and toggle it, there are no issues, both go up and come down nicely...
I do have a set of HK struts I put on instead of the stock piano wire and it fits in the cut-out without touching the sides or bottom of the tract...

I initially thought it might be a voltage issue and was going to run a separate pack for the retracts and I may still do that, however with the consistency of it failing when upright and not having any problems when inverted almost leads me to believe the weight of the strut (which is nothing) is holding the retract down when in the closed position, therefore tripping the overload protection....
I can't see any adjustment screws on the unit other than the 2 holding in the strut itself...


Has anyone come across anything like this? I'm almost out of ideas...


Thanks
Jazzbone
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Old Nov 24, 2012, 06:20 PM
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United States, TX, Leander
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How about loosening the mounting screws on the offending retract, see if it works then. If it does, the retract mount is not true and is torquing the retracts causing a bind. That's where I would start. If that's not it, swap sides with the retracts to make sure it follows the retract. Once you know that, you can zero in trouble shooting the retract or the mount. You fix an untrue mount by re-beding it with either epoxy or JB weld. Smear the glue down, lay some cling wrap on it then set the retract in place (make sure its straight) until is cures. Re-drill the holes.
Edwin
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Old Nov 25, 2012, 08:06 AM
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I would second Edwin's recommendation. The alloy side frames on these units seem to be less forgiving than plastic.

I flew Rare Bear last week and the RH unit bound up half way. Strange as they worked fine on the ground. Had to belly land.

Anyway, with a bit of detective work I found the source of the problem. During a wing rebuild I fabbed gear mount assemblies that had the units fit tightly into a pocket for strength. Unfortunately with the long legs the plane had the tendency to nose over on grass at the slightest opportunity. I added shims to the aft mount surfaces to angle the legs forward a bit and did not realize the side loads this would impose on the frames. As soon as the stress was relieved by loosening the mount bolts the retract worked fine again.

In my case as the main mount surface is 1/4" ply and perfectly straight an easy fix as simple trimming of the pocket is all that is required. You may have to use a flat block or other methods to check if the surfaces are parallel and true. You also need enough clearance to the side plates to allow the trunnion to travel AND above and below the side plate motor extensions to ensure the motor does not bind when pivoting to follow the trunnion geometry.
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Old Dec 08, 2012, 10:27 AM
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dont know if this the right place to post but am build a corsair electric w/ retracts and nav lights am wondering about installing lights on retract channel as this was the only time i believe during wartime that they used kifgts how bout some help here
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Old Dec 08, 2012, 10:29 AM
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ps,am using electric retracts from wing span and absolutely luvem no issues as of this date
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Old Dec 08, 2012, 08:12 PM
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I'm glad to hear about the wingspanretracts. I've been eyeing them for awhile and am planning on using some on a future .60 size corsair build. Then maybe upgrade my H9 F6F and P40.

What kind of nav lights are you thinking about, the flashing strobe. Electrically, you can do it, but it might cause interference. I followed a thread a few weeks back about a guy having interference problems using the RAM flashing strobe light kit. He was getting servo jitters. Just an FYI, you might want to search on RAM flashing strobe and see what you find. I forget exactly what he did to solve his problem.
Edwin
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Old Dec 10, 2012, 12:40 PM
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United States, IA, Rockwell
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Quote:
Originally Posted by oedjrplanenutz View Post
ps,am using electric retracts from wing span and absolutely luvem no issues as of this date
I also am looking at the retracts from WS. If i continue with the build, ( think I will) of my Zlin 526 I was going to use the WS units.

How is the speed. I was thinking they might be a bit slow, but I don't really have anything to judge by. The Zlin is an 83 inch wing and I'm told about 12 to 15 pounds. Do you think any issues with this plane?

Ken
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Old Feb 17, 2014, 01:07 AM
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eflite 60-120 retracts

I have just seen this thread. When I tried my eflite retracts I found them to be very intermittent. One leg would move and the others would not. the leg that moved was not the same one every time. I was using the tri lead and plugged it into the gear channel.. I tried a higher voltage on my regulator but no help. I have an Orbit Power Jack 6014, that plugs into my 6014 RX. it provided a stable 5v signal voltage to all the channels and also provides full input voltage to all servos. They worked perfectly every time. All legs move every time. So it seems that the Futaba signal voltage will not drive three retracts,(or 3 servos for that matter). The Orbit gives 5v to signal all channels.

Perhaps this might help someone who having the same trouble.
Regards

Tom Watson
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Old Feb 17, 2014, 04:34 AM
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I had the same intermittent operation with mine until I ran a separate pack for them.
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Old Feb 17, 2014, 02:53 PM
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Hi Bob, I tried that but it did not fix the problem. My problem was low or variable Signal voltage. The actual servo voltage did not make any difference.

Glad yours worked OK.

Regards

Tom Watson
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Old Feb 17, 2014, 05:07 PM
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Tom, do you think it was the units taking a higher signal level or just a high resistance in the tripple Y? I use FrSky rxs and conventional Y leads chained to allow for hooking in a battery and I seem to get clean switching.
Something to bear in mind though.
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Old Feb 17, 2014, 05:25 PM
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I have only the main sets of the 60-120, so only use a Y-connector for them. However, you may want to ensure you have good connections at the plugs AND a good quality and gauge wire.

tommywatson, I have used Futaba receivers for years with no servo signal issues. In your case I would suspect a faulty or loose terminal in the plug. bad solder job where the leads are tied together, or what I call the "Star Wars" problem.

"Using the Force, Luke" can push the pins into the receiver body. This may either prevent full contact in the plug or break the solder at the base of the pin, (or even crack the board, but not too common). You can also have a loose or bad connector inside the plug body. If they were misaligned during crimp either the insulation was stuck into the conductor portion of the crimp or the spring portion may have been damaged.

Any of these can prevent a good signal transfer.

Another may be created if your gear channel ATV is not wide enough or if that is the case if you have another channel mixed in for a secondary gear output. If the ATV is borderline one way or both, then you may find one of the gears not as sensitive to the signal flipping over center.

One last issue is wide spread, gets ignored and is more important now than ever, (and may be what BrumBob was experiencing). Most of the switches supplied with radio systems and aftermarket replacements are basic and really only rated to 4A. That may have been fine years ago with the common setup using 4 analog servos fed by a 4 cell NiCad. If you start adding on long servo leads, digital servos and the high current demands of servoless retracts when either the extend or retract cycle begins then you are pushing the capabilities of the system to deliver clean, reliable power. Due to that I opted for aviation grade micro switches in my power panel for Rare Bear and others with more than stock system demand.

You can see a pic of it here. Both the switches are DPST, meaning ON-OFF with two independent sets of contacts for redundancy. Investing in good grade switches mean the spring pressure allows for higher vibration before you encounter contact bounce, as well as coated contacts and a solid switch action that minimizes arcing.

NOTE: The Rx power is separately fed with a small 4-cell NiMH pack, (monitored to the left) while a 2S LiFE through a 20A regulator set to 6V supplies the rest of the system. Rock solid reliable with no brownout vulnerability.

p.s. One last thing I forgot to mention was what is called "Black Wire Disease". If a system has been plugged into a battery for a LONG time, (usually measured in years) EVERY negative conductor can actually start to oxidize inside the insulation, hidden from view. The same can occur to the switches inner components and plugs. All of this can add to high resistance to current flow. You may still show normal voltage when idle, but start asking for current and the power system will sag. The same can occur with bad solder and crimp work, so the only way to tell is to measure voltage under load at the component showing the issue.

This is why if I ever grab a used aircraft the power system is the first to go. Same with old servos. They may simply need lead and plug replacement to get them back up to snuff, but never trust them without testing.
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Old Feb 17, 2014, 06:26 PM
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I just installed these in a TF Spitfire and ha similar issue with one retract. I found that if the mounting plate isn't perfect, then you may have to tweak the mount with a washer under one mounting screw or just - like in my case- a 1/4 turn loosening one mounting screw will fix the problem. I know someone already mentioned this... but just experiment with the mounting plate on the offending strut. In your case, being inverted must straighten out the plate allowing for release of the gear.
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Old Feb 17, 2014, 08:38 PM
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A relatively easy way to ensure perfectly parallel mounting flanges is to mix some epoxy with FLOX, AEROSIL or even microballoons to a relatively thick paste and apply a thin bead on each flange. Then lay on some thin plastic sheet and lube the bolts, (and perhaps the retract bodies as well) with grease or Vaseline before dropping the retracts into place. LIGHTLY tighten the bolts and check operation to ensure no binding, wait till the epoxy mix sets.

Once this is done you can remove the retracts and plastic, then trim any excess. The final result should be a very thin layer of epoxy to make up for any low spots. Reinstall the retracts and tighten everything down. They should work fine now.

If you follow the pics, you will see how I made complete mount assemblies with the flanges one piece relatively thick ply. This ensures I have a solid and flat base. First three are Rare Bear, (I countersink set the flanges on that one) second set is of a Harvard, (Canadianized AT-6). Stock, the Harvard is notoriously weak since there is no continuous front mounting system, with that mount block open-ended at the wheel well.

In both sets rib patterns from soft balsa sheet were transferred to ply and cut to shape. The large slots fit the sides of the retracts to prevent loads from transferring to the flanges and causing stress cracks or bending. Everything slides together like a puzzle and dropped into the wing. A lot of test fitting to ensure the ribs fit closely to the skin and match the original rib position, then the ribs are tacked to the mount with thin CA. Final installation has the epoxy/FLOX mix used to bond everything together. It has the capability to fill any gaps and is structural, so once cured is EXTREMELY permanent. Also, since it is a module, the mounting should remain perfectly flat for life.

If you have the nerve to gut the original mounting, this process is adaptable to pretty much any wing type and far exceeds anything I've seen in kit or ARF form.

Also make note the final pic shows what I hope is the last of 4 complete design changes, with custom fabbed trunnions, (a few hours with a Bridgeport) and some very altered Robart struts. Still waiting for weather to test fly.
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Old Feb 18, 2014, 03:56 PM
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Quote:
Originally Posted by BrumBob View Post
Tom, do you think it was the units taking a higher signal level or just a high resistance in the tripple Y? I use FrSky rxs and conventional Y leads chained to allow for hooking in a battery and I seem to get clean switching.
Something to bear in mind though.
I think it was the futaba signal level and perhaps the fact that futaba signal level drops when trying to supply several servos. I had a similar problem years ago with a 1/4 scale Christian Eagle. It had 4 aileron servos and they displayed the same problem. Anyway the Orbit Signal booster fixed the retract problem permanently even when using a 5 volt NiCad pack to power the units.


Regards
Tom Watson
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