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servos for IMAC

Old 06-18-2003, 03:34 PM
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Default servos for IMAC

Are 61 in/oz enough for a 1/4 scale plane, or should I go more in/oz on the rudder & elevator Will be doing basic maneuvers with 135 Moki engine. Thanks
Old 06-18-2003, 03:38 PM
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Default servos for IMAC

what does the manual rec? for the bird as oz needed...
Old 06-18-2003, 04:08 PM
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Default servos for IMAC

I dug out the manual and they show JR4131 a core less in the picture with 90 in/oz on the ailerons, does this mean more in/oz for the rudder & elevator as they give no recommendation for these. thanks
Old 06-18-2003, 10:42 PM
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Default servos for IMAC

i run the hitec hs 645mg on all my controls on my 25% sukoi and have had no trouble in over a years worth of flying
Old 06-19-2003, 12:01 AM
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WreckRman2
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Default servos for IMAC

Hey Dick, Is this for the Fiesta?

You might consider the Futaba 9202's or JR4721's also.
Old 06-21-2003, 02:48 AM
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Default servos for IMAC

I've recently been building an IMAC gasser--80"

I spent my last two seasons screwing around with analog servos that had marginal torque for the plane.

I knuckled down and bought some really nice JR coreless servos for my 80" gasser and one JR digital for my rudder. It sure makes a heck of a difference.

I have decided to buy servos that have almost 50-75% more torque than the kit manufacturer recommends. I know it might be overkill, and it's expensive-- especially the JR servos- but I feel confident with my equipment now and that feeling can't be replaced by anything.

I'm running a 6volt pack . My plane recommends 68 ounces on all the surfaces. I've got about 75-80 ounces on each elevator half--thats double the kit recommendations. And I have 4131 on the ailerons. Thats about 110 ounces on each aileron. I have a single JR8411 on my rudder. Thats about 170 ounces.

You can't screw up by using too much torque. As I said- it may be overkill-- but if your running a big engine and your going to fly hard-- it can't hurt to have too much torque.
Old 06-21-2003, 03:19 AM
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Default servos for IMAC

the good thing about buyng better than what is needed servos is, it gives you an excuse to move up to the next bigger bird when you feel the need, sevos will not be what you have to buy to move up...
Old 06-24-2003, 02:58 PM
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Tony Fandino
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Default servos

For me hands down a quality core-less digital servo is the best bet.
I went from using hitec 645 mg to jr 8411 and it is a night and day difference. My 645's center would drift with a varying supply voltage say 5.5v to 5.0 gave me about five clicks of trim to bring it back to its center. no to mention the speed and accuracy.

My recommendation is to spend a little more (well allot more.)
and get the jr 8411 . You will not be disappointed.
Old 06-24-2003, 07:32 PM
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Default servos for IMAC

What controls would give the most noticable difference using digitals vs analog?
Old 06-25-2003, 02:43 AM
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Default digital vs analog?

I would think that it would be noticable on all the surfaces.

With my old Hitec analog servos on all surfaces, you could easily see the poor centering on all the surfaces. It made the plane hard to fly- (Sig Cap 231 EX ARF). The plane was always rolling one way or another and I was constantly making pitch adjustments with my trim tabs in flight. Landings were difficult, because the rudder would be slightly off center and it made the plane track funny on final and on the runway.

The coreless JR servos come back to center perfectly everytime . Maybe not perfectly, but it's about as good as I can see with my eye and a control surface throw meter.

The JR digital 8411 is superb. My rudder comes back to the same spot every time, with no "hunting" around the center. It just comes back, BAMM!! and on center in the blink of an eye. I love it.

I am going to run a coreless servo on my throttle too. I think that it might help me to "feel" the hover more. If your throttle doesn't move the same amount every time and it can't find the same idle on every landing, it could make your engine difficult to manage.
Old 06-25-2003, 02:58 PM
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Tony Fandino
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Default digital servos

You are absolutely right. Use the digitals where ever you can afford them. The most noticeable surfaces are elevator and ailerons followed by rudder and throttle . Yes even on the throttle.
What response... Together with my 106q2 it is totally awesome. I Have never had such a linear response on the throttle before.
So for all you guys serious about Imac invest the extra money and get good core-less digital servos like the Jr 8411.
I have not had a chance to try the new Hitec digitals to see how good they are. I do know that some pilots are starting to use them, But i don't know of anybody who has switched from
the Jr's to the hitecs.
For my money the jr 8411 is what i use


Anthony Fandino
Imac 3588
AMA 26298
Old 06-25-2003, 05:04 PM
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Default servos for IMAC

Thanks guys for all the good advise. These servos are going in the 60-90 Fiesta by Mecca Models I won at the 2nd I-Net fly in, which was the best fly in I have ever attended, the 1st was a blast also, and next year will be even bigger & better. I ordered JR 4131 servos with 90.4 in/oz at 4.9 and a 91FX for power. I hope this will be a good combination for this bird.
Old 06-25-2003, 05:34 PM
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WreckRman2
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Default servos for IMAC

If not let me know and I might buy it. I loved how well that plane flew. People always talk about how a plane flys on rails and I've never flown a plane that I felt fit that discription until I flew that Fiesta.
Old 06-26-2003, 12:44 AM
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Default servos for IMAC

Sounds good. You guys may have another convert!
Old 06-27-2003, 01:52 AM
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Default Flies like it's on rails.....

For me; that would be the H9 Cap 232 25% plane. I had one. But a failed Hitec servo on the rudder caused it's early death. Stupid Hitecs.

Mine weighed right at 12 pounds without fuel and balanced just slightly tail-heavy. Aileron rolls were very axial and snaps were crisp and predictable with no overrotation.. I miss that plane. If I ever build another one; I'd use a gasser.

As for the JR servos. I couldn't be more tickled. I'm using the 4131's on ailerons and the low profile 7005's on the elevators with a single 8411 on rudder and I'm searching for a cheaper coreless JR for my throttle.

I'm absolutely amazed at the difference in the coreless servos when compared to a typical standard or analog servo. It's totally worth every penny to have a nice servo that centers well and has plenty of torque to boot.

Good luck with the fiesta.
Old 06-27-2003, 06:21 AM
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Default servos for IMAC

Originally posted by Geistware
What controls would give the most noticable difference using digitals vs analog?
I would have to say all of them. If you are gonna fly precision aerobatics, there is no control that is any more important than the others. Unless rolling, those wings have to remain level so precision on the ailerons is a must. On the elevator you must have precise control to nail those lines... 45's, verticals, hrizontals, wind correction, and 60's. The rudder is probably the most important...generally there is always some amount of crosswind, so to maintain your line, and track properly you have to have a precise rudder. The rudder is also important during rolls. You cannot be accurate if you are fighting the plane because the servos are not going where you command them. The recommendation to use the 8411's or appropriate digitals was a good one. Yes, they are more expensive. With that expense come higher performance, and reliability. JR has been the leader in servo development and technology for years, and the 8411 is just another example of that. I've seen the Hitecs before, and while I have seen them at meets work, I have also seen them put in a $10,000 FC Extra. Needless to say, that didn't impress me at all. I don't think I would take a chance on those personally. Can't say I've seen anything that eventful with the 8411's. I like flying...digging a $1500 engine out of the ground is not my idea of fun, but that's what happened in the case of the Extra above. You pay your money, you takes your chances, but my money will go on the good stuff.
Old 06-30-2003, 11:03 AM
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Default servos for IMAC

From the flip side of this debate, the only surfaces I have ever fluttered with "digital " servos on them had 8411's, and they were less than 25 flights young. They also experience extremely premature gear wear and bent pinion shafts. In fact, you could say taht JR digitals are "famous" for antics like bad gear wear, "wobbly" rudders, and being overpriced for what you get. Heck, you even have to put an output shaft brace on an 8411 to get the top of the output shaft to not MOVE under heavy loads. Add $12 for the braces, per servo, if you want the JR's to not rock the output shafts.

On the other hand, I've had one questionable HiTec digital in 3 years using HiTecs, and with as many as 200 flights on a set of 5945's still have tight, strong geartrains. My 5735's (I own about 10) are the most bulletproof servo I've ever seen. Add in programmability, less expensive pricing, and a warranty that MADE JR and Futaba improve theirs (gee no one did 3-years on geartrains till HiTec did. . now everyone does it) and you could not GIVE me a JR or Futaba servo now.
Old 06-30-2003, 04:53 PM
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Default servos for IMAC

Hi,
Personaly I've tried Futaba 9206's which are coreless analog servos, they work great for me and are cheaper than 8411's.
Incidentily I also know of a few people who have had 8411's fail on them. On the flip side I've had hitec servos last about 2 weeks before theyre knackered!...but I've also had Hitec servos last years!....just depends wether you get a good 'un!!!
Old 07-01-2003, 01:24 AM
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Geistware
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Default servos for IMAC

I do want to stay away form metal servos because of wear and to replace the gears is a $35 investment. I know the Hitec 5925 has a plastic gear in the center. My question is does this gear prevent the servo from having slop over time?
Old 07-01-2003, 12:41 PM
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Tony Fandino
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Default Gear wear on servos

Well it all depends on how much vibration you have to deal with.
Most of the wear on the servo gears happens on the two gears closest to the output shaft. The plastic gear on the bottom is seldom effected. Except when the servo is overstressed the plastic is the first to break.
My experience is with jr 8411's . A good practice is to replace the gears once every season on the surfaces that work the most and suffer from alot of vibration.
Old 07-02-2003, 05:32 PM
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Hi,
The plastic gears prevent damage to the motor as they DO fail if overstressed!!...for Futaba S9206's they can be sourced seperatley. I've had to replace the metal gears in my elevator servos about once a season which i thinks a good price for a) good maintainence b) peace of mind! Especialy when I'm currently putting in at least 140 flights a season on the same aircraft.
Regards
Rich
Old 07-03-2003, 01:33 AM
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Default servos for IMAC

I finally received my 91FX and one servo from chief, as the others are on back order, so hopefully will get them in a few days. I actually bought a pitts type muffler for my OS engine at my LHS cheaper than on line, as I try to support them when ever I can. Will be ready to fly in a week I hope. You can see the Fiesta here sold by Planes Plus. $299 for either the yellow & white or blue & white.

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