mrsand

Gentleman,

Below is a message sent to Futaba about my retract problems on the Hellcat..I should have stated that I was using a JR 791 retract servo instead of Hitec. A representative replyed and wanted to know if I had tryed a Futaba retract servo...After reading below Does anyone have any advise? The JR has 260oz of torque...the Futaba S136 has 92...don't even know if that would solve the probelm anyway.


I have been using the 7C 2.4 transmitter with 617 receiver for a year or so on 4 channel planes using basic setups with no problems. I now have a 5 channel plane from Hangar 9. The plane appears to be properly setup. All channels appear to work but there are two problems. The retract gear is set up on channel 5 to switch E on the transmitter. Sometimes all works fine..then the next day the switch doesn't work the gear. The retract servo appears to be ok (Hitec 791). I have plugged it directly into the receiver or a 6 inch extension..I have changed extensions....sometimes the switch won't operate the gear. Then after fittling with it the gear works...but only when I flip the switch then move the elevator stick..then the switch is flipped again and the elevator stick is moved and the gear moves back. This might go on for several minutes...after which the switch again works and the gear goes up an down on the switch only. The parameter is set for channel 5 switch E. All mixes are Inhibited. I have tryed moving the connections around to see if shorts occur but that didn't seem to matter. Thats my main problem. The other is channel 1 won't work with a 2 into 1 wire harness from the dual ailerons. I can use channel 1 and 6 though..is that normal? I appreciate any help you can give me.

aghost

My Feedback: (13)

I have the Futaba 7C 2.4 transmitter with the JR 791 retract servo in the H9 Hellcat. I forget which receiver but its a 617 or the equivalent. The JR retract servo is on Channel 5, switch E just like yours. Its been in service since May, 2008. I haven't had any trouble whatsoever. No stray gear movement at all. Have you run the JR servo on anything more than a 4 cell receiver pack? That can ruin the servo.

I doubt the Futaba S136 is really strong enough. Seems like I had a Hobbico with about the same power as the Futaba on the H9 Corsair. It worked OK most of the time, but any problem (battery not fully charged, wheel touching the wheel well, etc.) and it wouldn't complete the retract movement.

Channel 1 should work with the 2 into 1 wire harness. I have that setup on a couple of other planes with Futaba 2.4 stuff. That seems like a receiver problem. The retract problems may also be receiver related. Do you have another receiver to try or have you done that?

Brian

mrsand

Brian,

The receiver is new and I have only used 4.8v with the jr 791..I do have another futaba 617..I'll rebind the existing one first then try the other receiver. thanks for the reply.

Mr.Sand

aghost

My Feedback: (13)

Mr.Sand, another note - I have 7 or 8 Futaba 2.4 receivers (606, 607, 617s). Over a couple of years, I have never had to rebind one other than moving it to a different transmitter. I would be kind of suspicious of mine (receiver or transmitter) if suddenly I had to rebind one, even if re-binding did seem to make it work.

Brian

mrsand

Brian

I exchanged 617 receivers....now the 2 into 1 connector for the airleron works in channel 1...and the gear seems to retract/deploy ok...for now. I am sending the transmitter and receiver to Tower for checkover. Unfortunately the trans. was dropped about 2 feet and jammed a toggle switch that has to be fixed. thanks for the help.

MrSand

aghost

My Feedback: (13)

MrSand: Looks like you have things headed in the right direction.

Happy New Year.
Brian

rcavi8ter

My Feedback: (19)

Has anyone hooked up the little gear doors on the LE to the stock retract with full gear doors? I have everything on and working with Robart struts and Chads doors but I can not figure out a good way to hook up the little door to lay flat with the gear retracts and be slightly canted forward when down.

RBean

I installed the small front doors on Century Jet Retracts. I use control hinges and used JB Weld to attach brackets to the non-rotating part of the retracts, a used a section of push rod wire as a strut, and use soft wire and two small holes in the door to attach the orther end. The slant of the door depends on length of the strut and location of the bracket on the door. Sorry, did mine by trial and error and didn't calculate the geometry. Here are some pictures but they don't show it real well.

mrsand

Retract servo problem,

Referring back to post 1401

I have a Futaba 7C 2.4 transmitter, a futaba 617 receiver and a JR791 Retract servo. The transmitter and receiver have been checked out all wiring is connected correctly. The Hellcat has been sitting in my garage a few months. It was flown on its maiden flight a month ago when operations checked out during pre-flight. But there has been a intermitent problem with the aileron and retracts not working during pre-flight. As explained in the other post...the retract gear is defaulted to switch e channel 5....the airlerons are on channel 1. Today the old problem appeared again. The retract wouldn't work unless the airleron or elevator toggle was moved. The gear wouldn't work on the switch alone. This seemed to be a programing issue. My buddies were perplexed. We connected the hellcat wing to my buddies hitec receiver transmiter on his corsair. The same event happened on that system...the retract would only work on the hitec transmitter when the rudder was moved!!! It wouldn't work on the hitec gear switch either..Puzzling. We now think the retract is bad. Can anyone think of a solution...or perhaps I need a new retract...any suggestions for a new retract servo for the hellcat stock landing gear that are adequate??

Thanks for any help

Mr. sand

bignasdy

im using the hiteck servo....no probs with it.....dont rally know what else to tell Ya...sorry... good luck though
d

mrsand

What model Hitec are you using Bignasdy!

Mr.Sand

bignasdy

hs 75 http://secure.hobbyzone.com/catalog/...HRC31075S.html
.....30 bucs...havent had any probs...hundreds of flights on the hellcat...
I gotta say, i did burn a couple out while installing them....I really dont remember why at this point in time...seems like I had em reversed or something, and they got bound up...but , after my lesson learned, no probs at all...
d

mrsand

Referring to posts 1401 and 1409,

I took the cat back to the garage and left it alone for a while. A few hours later went back out and I couldn't get it to fail again...all worked fine. I may not understand the radio programing. I intend to not have any mixes set up in the radio. Now I know (aghost) has a similar setup to mine....2.4Futaba 7C, Futaba 617 receiver and JR 791 retract servo. That being said...If anyone has that setup..what does your mix on P-mix1 say? heres what is in my transmitter-
P-MIX1 CH16
RT + 0%
+ 0%
OFS SET

P-MIX1 OFF
MAS CH1
SLV CH6
SW A

I apologize for this questions format...if I need to move to another part of this blog..I can...but thanks for your help in advance.

Mr.Sand

mrsand

I may have solved my programing problem. I found that by setting up...Inhibite...on each mix on the Futaba transmitter the mixes will not work whether programed or not.

Mr. Sand

aghost

My Feedback: (13)

Hi Mr. Sand, You could have a bad retract servo. I don't really see that the P-Mix1 should be doing anything based on the readings. However, "Inhibit" is a good place to start. I think you are only using 5 channels. If so, you should be able to inhibit all the mixes P-Mix1,2,3, Flaperon, FL-Trim, Air-Brake, etc just to be sure they are not interferring somehow.

On another item - Be sure you set the fail-safe throttle setting to idle.

Brian

mrsand

Brian

I had some unintentional programing in the mix...I removed it all by inhibiting every mix. It seems to work fine in the garage, I've cycled it a dozen times wiithout fail. I did however hook it up a few days ago unintentionally to a 6 volt system on a friends corsair to check it for a few minutes. That was before I inhibited the mixes. If I bought another retract servo other than the jr 791 do you have a recommendation? I would have bought futaba..but it appears their servo only puts out about 1/3 or less of the 791. Thanks for your help

Steve

aghost

My Feedback: (13)

Since my JR retract has worked well, I haven't done any research on others. I think I had a HS-75 (Hobbico or Hitec?) on the H9 Corsair (several years ago, now history). The Cat has the same retract. The HS-75 has much less torque than the JR. Even though the HS-75 must have worked for me then, I would not go back to a servo with much less torque than the JR.

Glad to hear your radio system seems to be working OK.

Brian

mrsand

Battery Overcharging

Is it possible that on-site overcharging of the receiver battery and or transmitter battery causes malfunction of plane servos? My Hellcat flew fine last week after charging up at the house and flying 45 minutes later. But yesterday I was charging up at the setup table and ground checking and once again no airleron or retract operation. After a couple of minutes the airlerons started working again and the retract would operate off the airleron toggle or rudder toggle like I reported in post #1401. After a few more minutes operating the controls the problem was gone and all worked fine. The receiver battery usually tops off a 5.8 volts. I measured the load at 5.5 volts when all seemed to be working again..
Does anyone have experience with this situation. Thanks for any help

MrSand

skorman

My Feedback: (3)

I would try another receiver and see if you have the same issues.

aghost

My Feedback: (13)

mrsand: Here's a link to an old thread about fully charged 6V batteries causing servo jitters. I suppose a 4.8V or 9.6V battery could do it also.
http://www.rcuniverse.com/forum/m_18.../tm.htm#186805

However, it seems to me that something is still not right, especially toggling the retracts with the aileron or rudder toggle. from your post it sounds like you charged both the TX and RX at the field, then saw the problem. You might try charging just one battery at a time to see if you can isolate the problem to just the RX or TX. Then try another RX or TX with the same battery and see if the problem still occurs.

my two cents worth.

as noted before my Hellcat and Futaba setup has been rock solid. Sure hate to see you having so much trouble with yours.

Brian

bignasdy

I have had to replace a few extentions over the years....Had aileron servos that when centered, the aileron would " barn door" back and forth a few times before coming to a stop....have only had the problem with my 6 volt systems.....faulty aileron extentions caused this problem, and I'd guess it has something to do with Yours...try that and see if it changes...I have a bundle of bad extentions in my drawer.... good luck...

BuschBarber

My Feedback: (2)

I have had more than my share of problems with Y Harnesses and Reversing Extensions. The Bouncing servos was very common and resolved by either switching to 4.8v or switching to a 20-22ga harness. I have a couple of JR 791 Retract servos in an H9 P47-150. They are not compatible with 6v. Horizon told me not to use 6v when I called about them being jittery at one end of travel. I use 5v regulators for each servo and no problems since then.

I try and avoid a Y harness or Servo Reversing wires. I use a JR Matchbox or Mix Channels in my Tx.

mrsand

I did some load testing on the receiver battery. I peaked charged it and it topped off about 5.8 volts...this is a 4.8v 2000 mah nimh battery. The JR 791 retract servo wouldn't work off its designated channel 5 and switch. When the battery finally discharged down to about 5.5 volts under load all worked well. This could explain why the system operated ok charging up at the house and checking out the system 45 minutes later and all working well. I would be interested to hear if this is the case for other Futaba transmitter/Jr 791 servo owners using 4.8 receiver batteries.
Perhaps if someone could also load test a fully charged 4.8 battery and see if the retract servo works when the voltage is over 5.7 or 5.8 volts.

Thanks for your comments to all.
MrSand

BuschBarber

My Feedback: (2)

I should have mentioned that I am using 2cell 2500mah LiPo Rx packs on all my aircraft, with either 5v or 6v regulators. I have not had a problem with the 791 Retract Servos since then.

mrsand

Flying the Plane

Got to the field the other day after charging up the batteries. I had to wait a while until the receiver battery discharged down to +- 5.3 volts under load..all began to work..I flew the plane twice...Now I have to fiqure out how to get a steady idle working the low speed needle. Plane comes in hot and roooollls across the runway. I did enjoy flying it. Maybe a on-board glow system would help...anyone have suggestions?

MrSand