PacificNWSkyPilot

My Feedback: (19)

At negative 35 degrees, there's no moisture in the air. I was nowhere near the ocean. I'm used to everything you talked about here. It's warmer now in Maine, but nearly thirty years ago when I first moved there we had 35 below for six straight weeks, every year. Lucky to get a week or more at -35 nowadays, with the warming.

But these days I'm in Texas, and I'd give anything to be back in the mountains in the winter. A few years back, my wife worked in the oilfields a few hours north of Fort McMurray for a couple of years. She said it was like Maine on steroids! Pretty cold and nasty. Good workshop weather at this time of year. Here, it's just damp and barely chilly.

~ Jim ~

Super08

My Feedback: (2)

Cool she will know exactly what it is like. For me it is the opposite when I travel down south I almost die. Was down in Georgia and Florida ten years back. I was just wiped right out in the heat. Couldn't cool down.

Tom Nied

Got the plane, got the DLE 35ra, now trying to plan out my onboard electrics. Are Hitec HS-645MG servos adequate or overkill? GP states Five medium medium servos with torque rating minimum 50 oz-in. I'm pretty sure I'm going to run a something like a 6 volt NIMH 2300 ma battery. Any thoughts? The HS-645MG are rated Stall Torque (6.0V): 133.31 oz/in. Troybuilt models have the HD-1501MG 236 oz-in at 6v Analog Servo with universal connector and Futaba arms at $13.95. Too good to be true.

Any thoughts?

Super08

My Feedback: (2)

645MG servos would be perfect. I have them in a couple planes including a Giant Stick. It has seven of them and I can fly all afternoon on an A123 2300mah battery.

Joystick TX

I'm using the HS-645MG servos and they work great. I bought some of the Troybuilt HD-1501MG's for another plane, but I never put them in because I was not happy with the centering on 4.8VDC batteries. They may do better on 6VDC. I have a note to myself to check them on the higher voltage.I'm also not sure about how long they will last.

ahicks

My Feedback: (2)

Re:the HD 1501s. As a sport flyer, nothing I'm ever going to do will depend on absolute centering. Plus, it's analog, right? If it were digital, I might have higher expectations? I LIKE the fact they're analog actually, as they aren't the power hungry pigs something this size in a digital might be? Regarding reliability, any servo, no matter it's price, can go out. The HD-1501 servos have been out long enough to have earned a pretty good reputation, right on par with the 645's? No longer too good to be true for me....

I'm an A123 convert as well. On this plane, they make even more sense due to it's size? There's also the potential of running the ignition off the same battery.... and still running all day on it! That's my take anyway, FWIW. -Al

Super08

My Feedback: (2)

BTW I didn't mention that I am running my ignition off of the RX battery as well. No problems with the setup. The 645's don't draw much power.

Super08

My Feedback: (2)

I just finished shrinking the covering on the wings and hinged all the control surfaces. I took a couple of pictures of how I do Robart type hinges. It is a technique I was shown some years back that works really well. After marking where all the hinges will go I make starter holes with a Dremel and a pointed grinding tip. It makes starting and centering the holes a breeze. Then I follow up with a drill. This way when you drill the holes the drill bit will not wander around. It makes hinging very fast and easy. I guess I will make the gear mount on the fuselage next and then I can begin building it.

PacificNWSkyPilot

My Feedback: (19)

The HS-645MG servos are excellent servos. I use the JR126MGs almost exclusively, because I've had great luck with them, but I'll use an HS-645MG if I have one around. They're solid, and inexpensive. Great sport servos.

Looks like you have a nice technique for installing the Robart pin hinges.

~ Jim ~

Super08

My Feedback: (2)

Jim what do you have for power in your Stearman? I used to have the PT17 version and ended up with a 160FX in it. The power was a little over the top, but was it fun to fly. It would do flat spins forever that were the tightest I have ever seen. It wouldn't really drop or climb but would spin on a spot as it held altitude.

As for my build I competed the gear mount. It is not perfect but will serve me well. I used Hysol epoxy so no way will the glue ever let go, the wood will break first. That stuff has incredible shear strength. Bad part is it takes about 6 hours to set up and 24 hours to cure. I used an old grimy set of gear for the mock up. I have a new set on the way from Tower that I will paint white before installing.

PacificNWSkyPilot

My Feedback: (19)

Super08, I powered my Stearman with a 30CC Syssa gasser. Lots of power, and it balanced the Stearman perfectly with no lead. I say all of this in the past-tense, because my Super Stearman is no longer with me.

No, I didn't crash it. A guy from California offered me so much I couldn't afford to say no! I'm still kicking myself for letting it go, but I'm now putting the final touches on an RC Guys 33% Pitts. It's just about the same size, though it looks a whole lot bigger, for some reason. The Pitts takes my breath away just looking at it, so I think I'm going to like having it! I went into all this because I wanted to mention that I'm powering this Pitts (as I mentioned, about the same size and weight class) with a Valley View 40CC opposed twin gasser, and if I like this engine, I intend to remove the Syssa from my GSS and replace it with one of the Valley View Twin 40CC engines. ****SIGH**** And I get to fit a new cowl again in the process. It never ends, does it?

I carefully inspected the work you did on your landing gear mount. What part did you say wasn't perfect? Because I looked pretty closely, and that is some excellent work. Better looking than mine was! After I broke my GSS in half on a power line, I took another run at it, and now my gear mount plate area looks like yours, but it was never that good in all the time before I did that. Nice work. The Hysol epoxy you mentioned must be a cousin to JB Weld, because those are the same set and cure times as the JB Weld. I know this because I was building linkages with carbon fiber this week, using the JB Weld. Anyway, the general rule among epoxies is that, the longer the set and cure times are, the stronger the final bond strength, so your glue is way stronger than the surrounding materials. You added plenty of bracing, which is real good.

I must recommend one small change. Loosen those metal cap screws, grab a hammer, and tap down on the cap screws to tap out those T-Bolts. Next, drill & thread the same holes for 1/4-20 threads, and harden them with thin CA (thin CA, harden, tap out, repeat). Use plastic 1/4-20 wing bolts to hold the gear on. As good as your work is, that undercarriage cannot take a solid rearward hit on the gear. The reason for that is simple. These gear are tall enough that they make a great long-handled pry-bar that will easily clean that undercarriage off the plane in a split-second. Twelve or thirteen pounds of plane rolling forward at twenty miles an hour, and then the landing gear stops. The glue will hold, the wood will break. I learned this the hard way, and all I did was roll it into some tangled tall grass. Rather than rebuilding that whole undercarriage once it's been ripped out, it's a lot easier just to stick a hot screwdriver into the plastic threads and screw them out, and use a little Monokote to patch the two wheel-pant holes on the bottom of the wing. Alas, this small drawback comes with having wheel pants, but they add so much in looks and class to a plane that they're worth a small amount of extra effort.

Al,
Between you and PGMeyer, I've been convinced to make the conversion to A123s on this Pitts project. However, I'm still too much of a chicken to use just one pack. One for the spark, one for the radio. I guess I won't have to recharge at the field, eh? I can tell they've got some serious capacity, as I've used the same pack throughout the build without charging it once so far, and it's still going strong. I'll typically charge a NiMh pack two or three times in the course of a build. Impressive.

~ Jim ~

ahicks

My Feedback: (2)

Geez, finally?

The more you use them the more you'll wonder why you're running anything else! I hope you're going to build in some power redundancy as well? Using a second lead and switch coming from the battery to power a Y harness in the rudder circuit not only makes a bunch of extra punch available to the rudder servo, it can back feed the entire system if anything lets go in the primary feed (switch, connectors, solder joints, etc.)!

Upside, redundancy on a section of the flight pack wiring that brings down an incredible number of planes ever year, plus extra punch (amperage) available for your rudder circuit (relieving this duty from the receiver's power buss, making extra power available to everything else?).

Down side? The weight of the switch and a Y harness. Pretty cheap insurance on a plane this size, but I use it in all my gassers. Right down to the Evo 10/Yak on my bench.... -Al

PacificNWSkyPilot

My Feedback: (19)

Not exactly sure of the setup you're referring to, Al. Do you have a wiring diagram? I'm sure I have all the components for what you're talking about. And this bird has TONS of extra fuselage space to work with.

~ Jim ~

Joystick TX

Here is the setup I use for all my gassers. It will work with all battery types. I agree 100% with Al, redundancy is a great idea. I have seen a lot of planes brought down by a single battery or switch failure. [ATTACH]1967161[/IMG]

PacificNWSkyPilot

My Feedback: (19)

I've used redundant systems before, and in fact, my thrifty, inexpensive solution to brownouts was to use a Y to incorporate the extra battery into the rudder servo wire, which I suspect may be what Al is talking about here. If so, I can say from experience that it works quite well. Much like with the 33% Pitts I'm finishing up right now, I often used a JR 8611A servo for the rudder, and that can have a heavy draw, especially moving those surfaces on the larger birds.

One advantage such a setup has over what you displayed here, Steve, is that it brings power into the Rx indirectly, through another wire, giving it another route if the first switch or its wires fail. Of course, my JR X921 Rx has a second port for additional power sources, so that's a nice setup But I'm partial to running it in through the rudder, mostly because the rudder can have a heavy draw, and that helps feed the rudder without drawing the RX battery down directly.

~ Jim ~

Super08

My Feedback: (2)

Myself I don't use a dual battery setup on my 50cc and smaller planes. However my larger ones that have much more money invested all have dual batteries with battery share. If you have dual batteries and one goes bad and shorts out the other battery will not save you without an isolation/sharing circuit. It will if one just dies or a switch falls apart.

ahicks

My Feedback: (2)

No diagram Jim. I think we've been over this previously though, using the Futaba heavy duty DUAL servo extensions? http://www3.towerhobbies.com/cgi-bin...&I=LXXA48&P=ML You have it described in your second note (our thrifty, inexpensive....)

With the power available from a genuine A123, anything I'm flying is well served by a single battery IMHO. So to get the redundancy I'm looking for, I use a second lead from the battery to feed the second switch? The second switch then feeds a Y placed between the receiver and the rudder. This allows power from the second lead/switch to back feed the receiver, supplying complete redundancy, as well as a big kick in available amperage to the rudder as the rudder now has a straight shot to the battery, avoiding the receiver's power buss.....

PacificNWSkyPilot

My Feedback: (19)

Yes, that's why, when I use redundancy on most of my planes, which are primarily in the sub-50 CC size range, I use simpler, less expensive setups. You can spend a ton of money covering every base, but you have to strike a balance, or every plane will have a fortune poured into it. I'm keeping mine limited to this size to avoid a lot of the spending I was doing with the larger birds.

Switches fail sometimes, but dual-pole switches fail less. Batteries short out, but they don't do it a lot, and that's why we (should) replace them with fresh packs at reasonable intervals.

~ Jim ~

PacificNWSkyPilot

My Feedback: (19)

hehehe, Al, I very well might have got the idea from you. When I see something I like, I have to try it! Clearly, it worked well, so. . .

~ Jim ~

Super08

My Feedback: (2)

I got quite a bit done today, The wings are completed and the servos have the throws set etc. The stab and fin are glued in too. Tomorrow morning I will start with gluing the hinges into the elevators and rudder and see where I go from there.

Joystick TX

A battery isolating circuit is not necessarily required with the setup I use. If a NiMh battery shorts, normally only a single cell at a time, it will bring the total voltage down, but there will be "some" warning. That is why I use the IEBC instead of just an opto-isolator for the ignition, or a separate battery for the ignition. As the voltage drops, the IEBC (Must be set below 6V) will shut off the engine before the voltage going to the receiver will cause a brown-out or loss of servo function which will give you time to dead stick the plane. If you can't afford a dead-stick, then you may want to use the isolation circuit.

I change my batteries every year and had one short after only a few hours of flying time, seems like it was only 5 or 10 hours. The plane landed okay on the second 15 min flight of the day, but the engine would not start. I checked the battery voltage and it was only 3.8 Volts. That's when I found the shorted battery.

If a dual battery setup using the LiFe or LiPo type is used then I would recommend an isolation circuit. Their failure mode will not be "graceful" without it and the high currents could cause a fire unless your wiring is designed for over 10 amps.

On another note: If you run a single battery with the IEBC, do not set the IEBC regulator over 5 Volts, that way if your battery voltage gets low, your engine will start to sputter and not run wide open which may give you time to land with at least some power.

PacificNWSkyPilot

My Feedback: (19)

Super08,

Just a suggestion, but the flying wires go on much more easily when you don't have the elevators or rudder to contend with, so you might want to think about doing them first.

~ Jim ~

Super08

My Feedback: (2)

I thought about that, but then they get in the way of mounting servos and linkages. I will safe them for last as I have done on some other planes.

PacificNWSkyPilot

My Feedback: (19)

That's funny. I did the same on this Pitts I'm building, and for the past few days I've been kicking myself, thinking, Dang! Why didn't I install them when it was accessible?

To tell the truth, I consider adding flying wires to be one of the more dreary tasks when assembling a plane, even though it really isn't that hard. So, it doesn't really matter when I do it, you can be sure I'll be whining about it! In fact, I probably should get started on it this morning, but if I know me, I'll probably find some convenient excuse not to.

1: Mercury has failed to align properly with Venus, so it might be dangerous to tackle such a delicate endeavor under such touchy circumstances.
2: This is too critical to handle without full lighting, and it's too chilly out there to open up the garage door right now.
3: I can't remember where I put that Sullivan Flying Wires package.
4: If all other reasons fail, we can fall back on the self-recognition that I'm a whiny baby and will probably procrastinate, or I might even put that off as well.
5: Flying wires? I'm supposed to put wires somewhere? Don't be ridiculous. I've already finished with the radio installation.
6: It's critically important that I go through all my old stuff and gather items together for the swap meet at the end of the month. No use waiting until the last minute.
7: Oh, look. South Park is on, and I have Ruffles.

~ J ~

Super08

My Feedback: (2)

LOL that was really funny, great way to start the morning.

I am still deciding if I am going with a single line or double lines. In my heart I know that it needs lines front and back, but just doing a single wire around the back is so much easier to set up.