Propworn

My Feedback: (3)

Wasn't commenting on the Hitec servos. I use Hitec exclusively and have for years I was commenting on how people will spend money to build a large expensive project then look for the cheapest things they can find for control. I have seen guys outfit giant scale warbirds with servos bought at a swap meet at Toledo where they have no idea the age or what that servo has been through. I have seen the same guys stand there slack jawed as their pride and joy ends up dirt napping because of a servo failure. The electronics in your plane is the last and most important control link you have. In my opinion cheapest isn't the best choice.

25 bucks is too much for an 89 oz digital Hitec servo what does he want someone to give him servos?

Dennis

kmeyers

I've my Sig "building and flying instructions" in my hand right now. They read " the elevator and rudder are each actuated by one "heavy-duty" servo. Almost every radio manufacturer produces heavy-duty servos specifically designed to handle the increased control surface weights and air loads of 1/4-scale models. Standard size servos are not recommended for the elevator or rudder of the Cub"

In the manual they are building with a webra .91 two stroke glow. I have a ST 3250 in my Cub (1.98 two stroke glow). Most guys today are putting in 20 cc, 23 cc, 26 cc, 30 cc and I think I will replace my glow motor with a 40 cc gas. Good servos are a must even with a small motor you can gain energy in a climb and need the heavy duty servos in a dive of a 12-17 lb plane.

jester_s1

You didn't say when that manual was written, but it probably wasn't this year. 20 years ago, standard size servos were only 50 oz in our so with nylon gears. Now you can get triple that with several choices of metal gears depending on your needs and budget.

Love2FlyMN

Sorry to spark a servo debate.

Keep in mind, it's a slow flying Cub, I really don't think I'm going to need 100 oz+ servos for ailerons.
If I was build a nice warbird that hauls ass, I'm definitely going to spend some change on more reliable electronics. This plane has almost a 10 ft wingspan, with a flat bottom airfoil, and 16" of wing chord. I don't think I'll be doing any speed runs or any aerobatic flying with it.

I did find some servos sitting in my old JR vibe. They're metal gear with plenty of torque.

I did some work covering this weekend. The Solartex is very easy to work with. I'm glad I went with it. I may post pictures later, we'll see if I have time. I'm trying to get it done before Christmas so I can maiden it with my brother in law. He's working on a 1/4 scale RV-4 that he's going to maiden the same day.

Still trying to decide if I want to just clear coat with poly spray, or spend the $50+ on the epoxy paint.
The polyurethane spray doesn't hold up to gas but it holds up to nitro? Can I just use butyrate dope (i think this is what they use for fuel proofing?)?

My other choice I have to make is paint color for the wing struts. I might just paint them black, or just try a yellow RustOleum and if it is way off color I can paint black.

Thanks guys!

kmeyers

I think you are missing the point. Heavy Duty is what they mean in context. As to "case size" this is after I made a recommendation of 100 in/oz. min.

And to the OP about servo debate, there is nothing wrong with debate and discussion.

I own and use high torq and metal gears analog and digital (in standard case size).

But it is simple as the weight and surface size increase so do the power needs of the servos.

I love my Sig Cub and will not risk losing it because of cheap servos.

SunDevilPilot

I disagree with running just "whatever" servos in a plane even when it is a Cub. I have three Cubs and all have high end brushless servos in them. These types of servos will outlast their brushed counterparts. Adding to this benefit, the main addition good servos bring is the precision centering the servos offer. I can tell when my planes are off even one click of trim and I use two step trims.

Run good servos... That's all I'm really saying.

You build a great model, it deserves to have good servos to make it operate as nice as it is built.

Airplane guys it seems do run some really junky stuff. Whatever is the "Cheapest" doesn't always made for fun at the field when it doesn't work well.

IMHO,

SunDevilPilot

(Bullet Proof Radio Setup)

Love2FlyMN

Those are some pretty intense linkages. I think a setup half as beefy as that would exceed the structural integrity of the control surfaces. To each their own.

My next question is my engine. I bought the plane with a G38 that had a bent crank. I bought a new (used) G38 off ebay that I'm putting on it. I'm fairly new to gassers

Love2FlyMN

Accidentally submitted that on my phone. ..
So I'm fairly new to gassers, and i have what might be a trivial question.
There's a wire that comes off the engine l that I'm assuming is for ignition (Not the spark plug wire ). My guess is it needs to be run through a switch to either power or ground in order to actually get a spark from the magneto, thus providing remote ign kill. Am i right? Does it need power or ground? If so, how do i hook this up to be a remote kill?
Thanks!

Steve S. Helland

My Feedback: (15)

The wire hooked up from the coil to the mag pickup is required for spark. Right now, the only way to kill the engine would be to close the carb all the way. I cut the wire, spliced and ran each end to a kill switch. Once the contact is broken it will not make spark.

Love2FlyMN

Right now my wire is just a floating end. Is the other end supposed to connect to the engine (ground) to allow for spark (or to prevent spark)? In this case I would put a switch between the wire and the ground to create an opening in the circuit. Am I correct?

I did some reading and it looks like when the circuit is open, the engine will spark, but if grounded to the engine, no spark. And i see that people are using a servo pushing on a limit switch. Pretty primitive, but It works

I do have an opto relay switch. Is there way to hook that up?

Thanks!

kmeyers

I would check for continuity on the bat in and bat out (-) of your opto switch. if continuity is there then operate the the opto switch through a reciever channel again checking continuity now on the (+) bat in bat out. These test will reveal how the relay works.

Love2FlyMN

OK. I'm thinking those opto switches are just little relay switches. Much like the PicoSwitch which I know would work.
I have some testing to do to figure that out. Otherwise I'll be hooking up a mechanical switch.

Steve S. Helland

My Feedback: (15)

SORRY about that! Yes, you are right...I had to run out to the garage and take a quick look, and yes the wire should go to the switch and the other pole of the switch should go to the engine bolt, mount, block, ground. Check out the picture...
And, yes you could hook up the optical switch in the same manner as you would an electro-mechanical switch.

Love2FlyMN

Awesome..Thanks!

All that's left to cover is the vertical stab and control surfaces. Then I need to install control surfaces and hook servos up, cut new windshield, and fix up the landing gear and she's ready to fly.

Oh, and paint it with polyurethane. I googled this and it looks like it's gasoline proof? If so I'm gonna go this route. I don't need nitro proof since I'm running a gasser.
Otherwise, can I coat the thing in butyrate (sp?) dope?

Thanks.

Love2FlyMN

Just did more reading and no, poly isn't fuel proof. Someone had the idea to just bring it to a paint shop and have them clear coat it? Others suggested thinning epoxy with alcohol and paint it on (this would yellow over time, no?).

Love2FlyMN

http://xlforum.net/vbportal/forums/s....php?t=1094717

There's this? I'm thinking it's worth a try.

Love2FlyMN

http://www.eastwood.com/paints/2k-ae...ay-paints.html
This, too.
Looks like it would be very easy to use.

spaceworm

There is/was someone here on RCU that staightened bent cranks. It may be that a prop strike caused the crank to twist at the counterweight journels. I.E. not really "bent". Someone should be able to fix it.
Or, please PM me if you want to sell the bent crank G38. Thanks.

Sincereloy, Richard

Steve S. Helland

My Feedback: (15)

I've just used TF Luster-kote on some of my giant scale gas powered airplanes. The Big Bingo shown above is base coat/clear coat urethane. You should in effect be able to go down to the hardware store and get some spar urethane and brush on a coat or two. Does that plain solartex fabric weave come already sealed? I'm curious because I've never used it or even seen it for that matter. I have used the old super coverite, Sig Koverall, 21st century pre-painted fabric (yuk) and now I swear by poly-lite (stits-lite) from F&M enterprises. I'd like to keep my options open however, and look at the solertex option. Do you have any pictures? I have been following your thread here on RCU to be able to help you as much as possible in your transition into the gasser world.

Steve S. Helland

My Feedback: (15)

The reason I ask if the Solartex is sealed or not is because it is detrimental that it is sealed before applying a finish coat of anything...if the fabric is not sealed it won't hold a vacuum during flight and lift will suffer badly.

Love2FlyMN

I do believe it is sealed. I'll send some pictures to my email so i can upload to the thread during break tomorrow.

I'm thinking now that i would like to give it a coat of paint before sealing. The "cub yellow" from solartex is almost like what I've seem described as "sun yellow" before. Does it darken to the orange-y cub yellow I'm more familiar with over time? Or should i find a paint i like and go wth that?

I decided to go with the R-Oleum engine block stuff that's gas and oil resistant. The reason behind the decision is if i ever have to patch the plane (crashes or when i add hardware for floats ), I'm going to want to match the clear coat the best possible. I'm not going to buy a $25 can of the two part just to spray one patched spot. The RO kind will keep in the can. We'll see how it goes!

I really appreciate the help and input from everyone!

Thanks!

jester_s1

Good exterior latex paint is gasoline proof. The semi gloss thinned out enough to flow out well would look right on your fabric. Do search for Ray Vaillancourt latex painting for a guide. You'll want to buy the higher quality grade on whichever brand you choose because it will have a higher ratio of acrylic to vinyl in it, causing it to be more durable in the long run. The only downside is that the latex takes several weeks to fully cure. So if you want to fly the day after painting, you'll want to use a catalyzed urethane or a lacquer. But if you can be patient, there are an awful lot of advantages to using latex. It does need to be thinned a good bit to brush though, as it will not flow out otherwise.

Love2FlyMN

Here are some pics.

Those are my two engines. The one with the wire is the Ebay one.
I never did reply about the guy interested in buying the bent crank one, sorry. I'm not interested in selling, I have a friend that knows a guy that will straighten the bent crank.

The one picture is a test spray of the clear coat. It's gloss finish so I'm not sure if I want to use it.

Love2FlyMN

Can anyone tell me what kit this actually is? Balsa USA was my guess..?

mogman

I think Balsa USA. The wings bolt through the side of the cabin.