AGR413

My Feedback: (1)

Awesome mod Jammer, that it exactly the kind of mod I thought about after I put mine together but I don't think I would have done near as good a job as you did. I be looking to see how it works out for you.

Stick Jammer

Original: thebluemax

Oh yeah, plenty of room. The carbon fiber tie rod is only about 1" down from the top of the rudders, just enough to clear the elevator at full down with full rudder deflection. I think the angle of the picture makes it appear to be lower.

AGR413,
Hey thanks for the compliment but there really wasn't much to it. I was thinking about doing it that way from the start, I really don't know why I didn't. The amount of money and hassles it saves is unbelievable. $32 for two standard deluxe tail servos verses $100 for four mini's. Only two 36" extensions needed instead of four. No reversing "Y" or channel mixing needed so a six channel RX works fine. Direction of the rudder servo and steering servo are the same so they can be Y'd together if needed. Total cost of the carbon fiber tie rod setup was under $4 (13" of 5/32 carbon fiber pushrod, two 2-56 ball links, pair of small control horns). I just epoxied short lengths of 2-56 threaded rod into each end of the carbon tube instead of buying the titanium ends which are the expensive part.

marktur

I used 81MG's for the rudders, but put them both on the same sides of the booms (one shows, so what?). This skips the needs for special wiring.
I put an HS125MG inside the stabilizer, and it works great. Using a 6v battery, it makes the servos faster and stronger, too.

You Turbine guys are pushing a LOT of weight around..it must glide like a typewriter, eh?

How fast is it coming in for landing? I think I would consider split flaps like the bigger one, AND spoilerons to slow her down on approach maybe? I'm waiting for Happy Jack to bring his out to the field...c'mon Jack - it's time!

fw190pilot

Yes landing speed is pretty fast I had spolerions hooked up but couldn't use them had way too much throw and wanted to roll the plane. Stall is pretty abrupt but will fly right out if you have enough room.

Stick Jammer

Original: marktur

Actually, if you go with dual rudder servos it doesn't matter which side(s) they're installed on. One inboard one outboard, both outboard, both inboard, no reversing Y is needed for any of the choices. I know it doesn't sound right and our minds want to tell us otherwise but take a close look at servo direction and which way it would throw the rudder(s) in each scenario. Dual elevator servos do require a reversing Y or a spare channel for mixing.

Xairflyer

My Feedback: (1)

To save having to fit reversing leads etc, most servos can be reversed easy enough, swap the connections on the motor (some motors have just wires other need desoldering from the pcb) and swap the two outer connections on the pot, I have done it to loads over the years.

opjose

So all four connections need to be desoldered and redone right?

e.g. swap the two motor leads and the two on the pot used to read the gear postion?

Xairflyer

My Feedback: (1)

yes both motor and pot, pot has three connections just swap the outside ones

marktur

Oh, too too hard...just use 1 elevator servo, and all the problems go away...



We now have tropical storm Noel brewing off the South Florida coast. It looks pretty strong - lucky there's a front coming through which will push it away, but flying for the next couple of days is just nuts - winds are 25-40 knots!

Waves are up however, so that's where I'll be. Man, I got the best 2 hobbies...cause when one gets bad, the other kicks in! (Surprised I've managed to stay married for 20 years!!!!

Stick Jammer

This works but have you ever opened the case of a mini servo? I consider myself pretty good with a soldering iron but I think brain surgery would be easier.

fw190pilot

The easy option is use a JR on one side and a same spec anything else on the other. Jr servos work backwards of everybody or is it everybody else is backwards.

marktur

Off the path question: I have a Spektrum 7....is there any way to use a Futaba radio with it in a buddy-box situation (for my son), or do I need to get a second Spektrum. (PS I also have an old JR radio laying around as well...)

Thanks,
Markm

Xairflyer

My Feedback: (1)

Use the JR it is compatible, lot more difficult to connect futaba with JR/Spectrum

All you need for JR/spectrum is a lead with a 3.5mm mono jack on each end

opjose

Yeah the Spectrum and the JR's use practically the same firmware programming...

Heck the Spectrum's screen looks identical to my old 8103's.

Remember that the "master" controller must be on, and the slave off.

Also the trims, expos and endpoints on both radios must be seperately set up, but identical.

After you have it working, check this by deflecting a surface identically on both radios, and flipping the trainer switch.

If the surface stays at the same deflection when you flip the switch, then both radios have the trims and endpoints the same.

Do this with ALL surfaces and directions.

XxOoCoBrAoOxX

Hey guys I was wondering if this plane the bobcat has any weak points in it? I want to put in a la 40 nitro motor and the recomended motor is a size .32 2c and I want to put in my 2c .40? If any one can tell me the plus and negative things about this plane, that would be great! pm if possible.

HERE IS THE SITE/PLANE---->>> [link=http://www.nitroplanes.com/sufa2539niga.html]Super Bobcat 25 - 39.4"[/link]

marktur

You're going to be much better off with a high-performance motor. Like the larger bobcat, you're restricted to prop size, so it's about higher RPM. I don't think you're going to see that with a "trainer motor".

larry11

My Feedback: (6)

Hey guys and gals,

What servos are you using?

I just got my bobcat 50 arf and am wondering what servos work best in this airframe. size, power, speed etc etc.

Please post what servos you found to be optimal and work best for ailerons, rudders, and elevator. throttle too!

thanks in advance,
larry

opjose

I used high torque servos on the ailerons.

Standard servos on the rudders and elevator.

Since I used the stock mounting positions for the elevator, two servos provide more than enough torque.

The rudders are not used at high speeds so standard servos work fine.

The ailerons are a different story...

I have mine set for maximum deflection.

At high speed my Bobcat SQUEALS when I give it full ailerons, so it is getting a lot of pressure on the ailerons.

littlepiston

My Feedback: (12)

turbine of glow?

opjose

Good point... if turbine, you are dealing with much higher forces.

littlepiston

My Feedback: (12)

i use for turbine
hs 225 for rudders
hs 5245 for wings and flaps
hS-5125 for elevator
and ecu for thottle

Xairflyer

My Feedback: (1)

True you may have a bit more speed with a turbine, but the surfaces are small on the bobcat, many people get carried away with big powerful servos.

If you want to fit better servos then most of the time a std metal geared servo will be a much better fit that say a 15Kg nylon geared version.

On my Turbine bobcat I fitted a hitec HS-5125MG inside the stab for the elevator, I would have been happy to fit the HS-125MG non digital version if it was not out of stock, I then fitted JR NES-517 std ballraced servos to the ailerons and HS-81's to the rudders, I always like to fit a metal gear servo to a steerable noseleg just to absorb the kicks they get especially on grass.

Just as a matter of interest a friend has a 1/3 scale J3 cub and has Futaba S148 servos (one on each) fitted to the ailerons ! now I think I would go a little better than that and I know it is docile and not meant to turn fast but this is a big powerful 44cc twin glow engine and it fairlly bombs around the sky. How can you argue with him as the model now is nearlly 20yrs old (as is the servos) long before digitals or super high torques were invented.

drbobsmith

I think I remember reading somewhere in this thread something about the digital servos that come with the Spektrum DX-7 are not appropriate to use in the Bobcat 50. Why is that or is that just an opinion. I'm not a jet jockey. My Bobcat is getting a Rossi 60 turning an 11x7.

opjose

I'm not flying a turbine, but I know that there is NO WAY that the STD JR servos will hold my aileron's at full speed and at full deflection.

There's simply far too much force acting to counteract the movement of the servos.

larry11

My Feedback: (6)

thans for the servo input guys.

i am still undecided to turbine or prop it. lol , i am still looking for a mw-44 for it. i think my p-70 is just to bug!!