Hey guys,

I'm getting pretty excited because I am close to getting this Dash 5 together after resurecting it from sitting in the bedroom closet at Grandma's house for the last 8 years!! Can you believe that!

Anyway, I need to get some servos and I am wondering what would be adequate for this plane. I decided to put an OS 61 with a pump and a Hatori pipe on it. I have an MK bellcrank assembly on the split elevator, a pull/pull on the rudder and there are separate aileron servos.

The control surfaces are small, I know, but it should be pretty fast so I don't know if I need some servos with a little more torque...or maybe just something a little heavier on the rudder.

Any thoughts?

Thanks,

Tom

Hey Tom,

do you have any specs on this bird?

Most 60 size pattern aircraft are fine with the usual high quality coreless analog servos (e.g., a Futaba S9001 or better) or digitals in the 50+ oz of torque. I like to use 70+ on elevator and the strongest on rudder but you can also run your system at 6V to speed things up and increase the torque. For ailerons and elevator your mostly looking for fast servos rather than high torque servos. The S9001 isn't particularly fast by today's standards but coreless servos are nice.

It sounds like you have a good control setup. Of course, you want to make sure the linkages are stiff. For the MK setup you might want to install your servo on its side for linear output and run an arrow shaft FG pushrod. I've been debating about using supported outer sleeves even on these pretty stiff pushrods for zero slop. It really depends on how long the shaft is. For ailerons, the turnbuckle pushrods make for a nice linkage and of course, P-P is great on rudder.

Which OS and Hatori pipe will you be using?

David.

Dave,

Specs in standard, converted from metric:

Length 61.02
Span 69.68
Weight 7lb 11oz to 8lb 9.5oz (I haven't weighed mine yet)

There is another thread on the engine as I am getting some good help from RC Universe on that too. It is an OS 61 RF with a pump and a Hatori #650 pipe. I have started my benchrunning and tuning and am currently getting 10,800 on an APC 12X11 with 15% Nitro 18% Sythetic/Castor blend powermaster fuel. I am in the middle of doing a little more tweaking there...the pipe is currently at 14 1/2 inches.

The name of the elevator pushrod escapes me right now, but it is the graphite type arrow shaft. Not the lightest but it is definitely stiff. I like your suggestion to run the elevator servo on its side. Since the fuse is pretty narrow, I may be able to stack the elevator on top of the pull/pull rudder servo...got to think that through.

I compared the specs on the futaba servo you suggested to a couple JR servos. There is a DS8417 with a metal gear: 82oz .10/60 degrees at 4.8 volts ; 98oz .08/60 degrees at 6 volts price is $114. They also have a DS8231 with nylon gears: 88oz .22/60 degrees at 4.8 volts ; 113oz .19/60 degrees at 6 volts $89. The ladder is what they recommend for pattern and jets and it is probably a little cheaper because of nylon gears. Both are in the ballpark of what you are indicating though and I should be able to work from there.

I'll try to get some pics of what this kit looks like. Thanks for your taking the time to help me out. I'm all ears if you got anything else!

Tom

I had one of these planes years ago in a tail dragger configuration. If you have the clearance, I'd consider the 13X10 APC prop. One of the weaknesses of this plane is that it has a pretty thick airfoil consequently it requires work to get it to snap well. I fly JR so I'd go with 9411SA on ailerons, 8411SA on rudder and then use an 8417 and replace the internal metal gears with 8231 nylon gears. I guess you could also use the 8231 or even a 8411SA on elevator too. These are what I use on my current 2M pattern ships. There is no such thing as overkill one sevos in my book. Digitals in my book is the only way to go as long as they are Futaba, JR or even Airtrronics. Hitec and other off brands are junk in my book.

Interesting comment J, I have heard others say replace metal gears with nylon or other non metal material. What is the reason for this. TIA

With time and vibration those metal gears start to wear. The nylon gears are tighter and remain tighter over time much better. This is important in pattern plane applications where precision is paramount. That is one of the reasons why JR has the SA designated servos like the 9411SA and 8411SA. In the case I described, we are replacing the internal metal gears. The servo arm gear need not be replaced.

Thanks J ,that makes a lot of sense.

Hey Joe, so did I. A really fine flying plane and mine had no coupling of any kind. The snapping issue was dramatically changed by adding stall strips on the outboard roughly 10" of wing as I recall. Never did do that maneuver well though, especially compared to today's stuff. Wasn't designed for that kind of flying

On servos, heck we flew 40-50 in-oz torques back then. Good servos like we have now simply were not invented yet

Promising to be a nice weekend. Hopefully I'll catch you down at the field

MattK