rightflyer

With the HD 35-42 and 4 -cell lipos, does APC 12x6e sound right?

rctom

Yes.

tankertoad

Just ordered the Slick. Tom suggested the E-flite Power 25, which I will probably use. Since there are 2 versions of the Power 25, does anyone know which is better?
The higher KV (1250) gives more power (850 watts), but uses a smaller prop (8*6) at higher RPM vs. the lower KV (870) has a little less power (600) and uses a 12" prop. I like the idea of the larger prop for 3D, but would prefer the extra power. Any suggestions?

rctom

Use the lower KV and bigger prop, 600 watts is more than enough.

tankertoad

Will do - Thanks Tom!!

tankertoad

Is anyone else using the HS-81 servo on this plane? I don't know if I got a bad batch or what, but these servos won't even move the surfaces at airspeed aero with out stripping. If you put a slight load on them, they skip. It's like the gears are sloppy and the motor is too strong. They center, but something is skipping or stripping inside.

matt_xb8r

My Feedback: (8)

I've replaced a couple of gear sets on my HS-81's.  Seems like every third trip to the field I'm stripping one.  I'm running more motor than the plane will ever need so weight isn't an issue.....think I'll be moving to 82mg's soon.

rctom

I never had any trouble with the HS-81s but it sure sounds like you have a broken gear. Consider replacing that servo, the HS-82MG is the same size and has metal gears.

Torque with either of these servos is not an issue, they are overkill for this plane, so it must be a gear train issue.

TF

tankertoad

I must have gotten a bad batch then. 3 of the 4 servos ( both elevator/ 1 aileron) I have are doing it. I'll pull them and probably go with the metal gear servos since I can't get the throws I need because they strip under load. Thanks for the info

JonPa

I had the same problem. Both elevator servos, which were HS-81s, stripped while in the shop. I must have bumped the elevator at some point, but it could not have been much of a bump because I dont recall doing so. Nevertheless, I have to replace them without having flown once yet. I think the gears are just too fragile. I made sure using a servo meter that there was no binding in the travel, so it was not just the 45 degrees of travel on high rates. I will replace with 82 mgs when they come it.

Jon

rctom

Just FYI I have located a nice digital metal gear servo (chinese) that I can sell for the same price as the HS-81s and will fit the plane without any modifications.

Unfortunately we are at the end of the planes' run so this comes too late, and if your plane is already modified for the HS-81s they won't fit any more.

Anyone buying one of the remaining planes, or who has an unmodified plane with less desirable servos may be interested in this development.

TF

tankertoad

I think the motor in the HS-81 is just too strong for the servo. Mine stripped in the shop too. They would go to the end of travel for the surface they were driving and make a ratcheting sound as the motor kept running and the drive train slipped. I'll open them up tonight to see if the gears are actually stripping. I suspect there's too much tolerance in the gear mesh and it allows the teeth to disengage and slip. Usually a servo will bind against the gears and stop, but not in the case of the HS-81. They recenter just fine (unlike a servo with broken teeth), which makes me suspect loose gear mesh. It's the first time I've ever used an HS-81 (I have a ton of Hitec servos), and I'm pretty disappointed with the results. What would otherwise be an awesome airplane has been neutered by a crappy servo. Since I've already modded for the HS-81, I'll have to go to the HS-82. That should fix the problem.

matt_xb8r

My Feedback: (8)

wouldn't setting the endpoint solve your issue?  I've never had the issue you describe.  Mine have just been broken gear teeth from hard landings or something of that nature.

tankertoad

I set the endpoints as I was doing the initial set up and noticed them stripping in the shop. On the first flight, I could tell the travel was even more limited as the servo couldn't push the control surfaces against the air load. I opened up the servos tonight and found no damage, but there's a lot of slop between the top two gears. The shaft pins on a couple of them didn't seem like they were seated very well, so I pushed them in as far as they would go. That seemed to help a little, but the servos are still stripping under load. I'm really suprized with this result as Hitec is not normally of such a poor design. I doubt the teeth would break on any of my servos because there's not enough holding the gear mesh together when they are torqued, they just slip. I went ahead and ordered HS-82 (metal gear) servos to replace these. I really hope they don't have the same problem. I'll probably also contact Hitec. It sounds like any body else who has had trouble with HS-81, was from them actually shearing teeth off the gears, not getting the kind of slipping I'm getting.

matt_xb8r

My Feedback: (8)

yeah I was losing a couple teeth each time on mine.  I use 82mgs in a few other planes i have and I have never had an issue with them.  I'm sure they will perform more to your liking.  Just surprised to hear you are having such issues with the 81s.  I've never had a  problem of this nature with them. or atleast not that I have noticed.

tankertoad

I did a couple of Google searches and found a handful of people describing the same problem going back to 2006. I called Hitec and they are sending me new gears for all my servos to try. They didn't seem to think the 81 was a good way to go on a 3.5 lb plane, so I have HS-82MGs on the way to replace.

JonPa

Has anyone had any problems with the hS-81s on the ailerons? I will replace the elevator and rudder servos with HS-82mgs (since the HS-81s stripped in the shop), but I wonder if I should replace them in the ailerons.

Jon

tankertoad

Mine stripped on one of the ailerons and both elevators. I'm using a HS-225BB on the rudder. I may have glued my hinges a little tight, but I really don't think HS-81s are a good option on this plane.

rctom

I have used the HS-81s with good success on several planes, so I believe that the servo, if operating properly, is up to the job.

However I am hearing here quite a few reports of what seems to be slipping gears which I have never encountered. If these reports are accurate then I would guess (I have no inside knowledge) that maybe Hitec has a bad batch. I say this because some work fine and others are clearly not working yet are not damaged.

If you have problems with a HItec Servo Hitec is very good about warranty service, I suggest that you contact them directly.

Meanwhile on the few remaining planes I am now selling an imported metal gear digital servo that fits the un-modified slots of the Edge/Slick and i have stopped selling the HS-81.

TF

tankertoad

Maybe mine were made on a Friday Those digital servos sound awesome. As much as I love Hitec, I would love to see more budget servo options on the market (just like Zippy did for the budget lipo). Oh and BTW, LOVE the slick (we got off on a rabbit trail...no pun intended, talking about servos) It is THE best crafted ARF I have seen to date.

rcpilot_971

My Feedback: (50)

What servo arms are you guys using on the 81 or 82 servos ??

JonPa

How is everyone setting up their planes? I switched over to HS-82mgs and set the rates to exactly what is recommended for high and low rates, and medium rates right in between. My concern is that on high rates I have the servos set at 110-140 %, but on low I am only using 30% of the servo travel. I have not yet flown it due to the weather, but my sense from reading about this plane, is that it is designed more for IMAC type maneuvers rather than 3D. I am just beginning to start IMAC, so that is what I want in this plane. Is it really a problem with modern servos to use such low travel % on low rates? What type of rates (low, medium, high) would you use if you were to only use the plane for IMAC sequences?

Jon

jsallade

In the interest of full disclosure here are my creds on this subject. I've been to IMAC judging school several times. Hang out frequently and discuss with several mid to high level IMAC competitors this kind of thing often. Have judged IMAC contests on maybe a dozen occaisons and flown in maybe 6-8 contests... always at basic level. I feel like until I get that down to a high level I don't need to fly sportsman (even though I can fly the sportsman sequenc with my plane... and have in practice). I have a WHEdge (30%) as my main aerobat as well as a WH Baby Edge as my "backup" IMAC style plane. I haven't flown the electric versions but can't see that as affecting this subject really. So for what's its worth, here's my 5c worth.

It is a basic axiom of IMAC (at least in my experience) that you can set up your plane to be ideal for IMAC or ideal for 3D but not both simultaneously. And I'm talking about mechanical setup here. I've seen guys that can do both by the flip of switch but they are compensating by their skill on the sticks for a lack of precision and "purposeful" setup on the airplane. They are also likely running servos that are huge overkill in terms of precision and strength for the task at hand and trading some of that excess back in order to stay reasonably precise and still have plenty of torque with less than idea control linkage configuration.... Can't be ideal for both at the same time.

For most of us, we need all the help we can get! To make it as easy on yourself as possible for IMAC you want to set up the throws (mechanically) so you have very little more than the most necessary travel to do your IMAC manuevers with your servos set up to their maximum (radio) available movements. In IMAC it's mostly about smooth. The amount of throw necessary for this is typically what most manufacturers would call low rates and often far below even that. (My Edge flies with about 1/2 to 2/3rds of what Tom calls low rates... mayb eless) If you are limiting this electronically and using only 20% of your servo throws then your plane will (almost by definition) never be as smooth as it could be. You are taking away all the precision of the servo by limiting it in this way. If they aren't digitals then you may even be giving up much of their strength as well as you are operating near centers and analogs don't produce their full strength immediately off center. You could end up with a sloppy feeling airplane that need not be so. Analogs will work well if used properly... i.e. using their full travel.

But back to your question... if you are wanting to set up your plane to be primarily an IMAC craft I would suggest you configure the linkages and travels with "just enough" travel. If you want to do both then a compromise is in order. Good luck with the bird.

rctom

Let me put a slightly more technical light on the question.

A servo, any servo, can only resolve its position to one pole of its motor. Using a 3 pole motor which is standard in low cost servos the best you can possibly hope for is resolution of 1/3 of a turn.

Now a servo moving full throw (60 degrees from center) uses maybe 150 motor turns, possibly less. You'd have to count the teeth in your servo (which I did once) to figure it out exactly.

So to move in any direction there are potentially about 400 stopping points between neutral and full throw. If you use 30% of the servo's travel there are then only 120 stopping points. So you can see that using low rates will not be as precise as if you used the full travel of the servo to get where you are going.

With smaller less expensive servos these numbers only get worse, so if you want to fly precision set up the mechanical linkage to give you only the throw you will need at 100% (some people extend this to maximum EPA for more resolution) and no more. Unused travel is wasted resolution.

TF

JonPa

Thank you very much for the information-I will take your advice. After flying it a few times today, I found that the low rates were quite nice for larger IMAC maneuvers and the medium rates (25 elevator, 20 aileron and 35 rudder) seemed too much for anything but inverted flat spins etc, which by the way are nice on this plane. Was too timid to try to the high rates just yet, since it seemed to be a bit too much. Just to clarify, are you running the suggested low rates (13 ail, 12 ele, 25 rudder) as high rates then 1/2 and 1/3 of those for low and medium rates for your IMAC routines?

and yes, the recommended power system with 4s 3000 nanotech pack gives about 6-7 minutes and insane power! You know, that gratifying vertical authority that makes you want do nothing but accelerate vertical over and over again.

Jon