Steve, thanks for posting the bomb rack drawings. I'll see what I can come up with when the time comes.

Well, several hours of carving, filing, and sanding later, here's where I am on the static prop. Actually, it was surprisingly easy to get approximately the right shape. It seemed pretty intuitively obvious how the curves had to go. Basically, I just marked "edges" of about 1/8" inch and carved down to just above that. On the backside it's a flat slant from the opposite edge to the LE. On the front, there's much more of a curve, particularly need the hub, so I carved down only the "downward half" (TE) of the face and then sanded that smooth.

I've still got to do some finally shaping. But it's not bad for 25 cents worth of lumber and a days labor!

Looks Great! What are you gonna charge for them???? hahaha

FA[8D]

More than 25 cents.

Now that is one fine portable fan!
Steve

Haven't you got one of those Steve?.....they never overheat whilst drilling

I made the metal prop hub using a resized photo of the one on the Bentley BR2 glued to 2mm aluminum sheet. I center-punched the holes then drilled them out, then sanded the piece to the outline of the circle. After cleaning this up, I centered the hub on the prop and used it as a guide to drill one of the holes along the edge. I then screwed in the bolt to hold it in place and then drilled the hole on the opposite side and screwed in a bolt. Once the position was locked in I drilled all the other holes and when I had all the bolts in I used the hub as a guide to enlarge the center hole to the size of the Saito drive shaft.

The last photo is another shot taken today in the local hills.

Well, I had a little set-back today as my engine "test bed" model (the 60-size Kyosho ARF) went down today in a big way. This was its maiden flight. Moments after take-off I was suddenly aware that I had no control whatsoever. I had done a radio check before take-off and was able to taxi to position and control throttle and rudder on the take-off run but then almost as soon as it lifted off, I had nothing. It made a large frightening turn off to the right as I yelled out a warning in Japanese and then went down in a tangerine grove behind the field. I think the engine and radio gear (and assorted other bits like the WB wheels I was "breaking in" ) are OK but the ARF is a total write off. [:@]

My best guess is that the Rx battery didn't have a sufficient charge. I had charged it overnight but I've been having some memory problems with the batteries that come with the Airtronics radio. What devices do you all use to charge your Rx batteries and to check their charge? At this point, I'm just blindly trusting that if I plug them in the night before (using the stock charger) that in the morning they'll be charged. I won't do THAT again!

BTW, for what it's worth, the take-off run and (short) climb out felt exactly the same as with the smaller Kyosho Calmato Sports (which I still have). Looks like I'll have to get another test plane (after I confirm that the engine still runs). []

Hi Don. I'm really sorry to hear about the accident.[] As an old C/L flier this is the aspect of R/C that scares the hell out of me. Loosing control and watching your plane self destruct has to be a terrible feeling. Thank God it wasn't your Snipe.
I check the RX voltage with a meter before each flight. My TX displays it's voltage. You can get a meter for about $15 at your hardware store. You might also consider a small set of wind chimes, just to chase away any demons that happen to be hanging around
Steve

I didn't even get the childish joy of watching it self destruct. Just of watching it nose dive behind the treeline. It took almost 40 minutes to find the wreckage.

Actually, this accident (and most accidents are caused by SOMEBODY failing to do something) has forced me to recognize that I really don't know anything about the electrical side of RC. All I know if that I have this battery that I "charge up" then "plug in." Looking at the battery I can see that it says 4.8V 700mAh Ni-Cd. This is the standard Sanwa battery.

Upon checking I see that my HiTec receiver came with a 4.8V/600mAh NiCd pack. A couple summers ago I also picked up "some other" kind of battery that wasn't supposed to have the memory problems on the NiCds. It doesn't have a label but the batteries say GP2300 series (there are the usual four in a row). I've got at least 2-3 completely dead Sanwa battery packs. This is probably the result of my sloppy charging technique where I'll plug the battery in in anticipation of flying the next day and then the weather will be bad and I forget to disconnect the battery. I also "top off" the battery (or at least think I do since I have no way of knowing the charge) after each flying session.

Anyway, I clearly need to get my battery use and maintainance under control.

What's the best way to charge Rx batteries?
What the best battery choice for the Rx?

The TX, of course, displays the TX battery power but I'm just "flying blind" in terms of the Rx batteries. [][]

How do I check the Rx voltage? I really don't have a clue about anything electric -- which is why the idea of going to an all electric model scares the bejesus out of me!

Hmm...well now I'm REALLY at a loss to understand what went wrong. I just did a test of the radio components using the same battery I was using on my ill-fated flight and everything works perfectly.

Was I shot down? What does being shot down look like? It sure didn't look like anyone else was controling the servos. As far as I know the only other user of my channel was the one who held my model as I was starting it. Our club operates a "take the channel tag" system of flight control and I had the tag.

In RealFlight I sometimes see the failure message: "Your radio was intermittantly locked out." What does "locked out" mean here?

With the complete loss you describe, I would look for a bad wire/plug. Turn the system on and move the wires around all of the connections,and see what happens. A wire can be broken inside the insulation and make contact some of the time and lose contact when moved. This happens mostly at the plugs.
Steve
PS Get the wind chimes.

Try as I might, I can't make the system fail at home. Everything seems normal.

I wonder how you say "gremlins" in Japanese.

BTW, this is one of my favorite cartoons:

http://ie.youtube.com/watch?v=3xXu_9JN3YA

Don, Several companies make battery cyclers. I think a very good one is the Accu-Cycle by Hobbyco; however, it has multiple capibilities and if you arn't interested in several of the capibilities it has, maybe a cheaper cycler would be a better choice. I personally have athe Hanger 9 Sure Cycle. This unit is set-up to charge/discharge TX and RX packs only. It cost around $50.00 and does the job fairly well. I basically use it for cycling RX battery packs. It will do TX packs, if removed form the TX and the pack does not have a discharge protection diode installed. Like you said, TXs have a bvoltmeter built in, so you know how they are doing.

While charging, the unit can be toggled through the amount of hours charging and battery voltage. When switched to discharge, it shows battery voltage and mAH drawn from the pack. When it gets to a predetermined point of discharge (I think by reading voltage) it automatically switches to charge and keeps the information on mAH in memory, so you can see what the final mAH amount was. When charging a new battery pack, this unit will tell you the values your getting from the pack Ie, an 800 mAH pack should produce close to 800mAH; 1500 mAH should produce close to 1500 mAH, etc... It may take several cycles to get the capacity the pack should have and if it never gets close, something is wrong with the pack.

Generally, NiCAD and NiMH are the two types of batteries supplied with R/C equipment. The memory thing has all but been eliminated from NiCADs. My guess is you might find you have NiMH batteries, which are suseptable to damage by over charging. I feel NiCADs are more robust and will attempt to use them if I have a choice. Here are two websites were everything you need to know about batteries as we use in R/C can be found. A description on how to charge NiMH batteries will be found at The Battery Clinic by Red Scholefield: 1). The Battery Clinic: www.rcbatteryclinic.com . 2). NoBSBatteries: www.hangtimes.com .

I'm no battery expert, all I have learned is from concern over loosing an airplane from lack of battery power. Using an Expanded Scale Voltmeter as previously suggested is also a very good idea.

Hi Don - sorry for the loss. I punched a hole in the ground last weekend with a Quest. Have to blame 3D flying below ground level, not the radio!!
I use 6v receiver batteries made by SR Batteries. They are more expensive but I haven't had a failure and the description of their batteries on their website in my mind is worth the extra $$. I believe 6v also gives more voltage headroom for cell failures. Consider checking your batteries under load. I put a Voltmagic monitor in my "less disposable" airplanes, but checking with a DVM is just as good provided you use one with an adequate internal resistance to simulate a reasonable load on the battery. The Voltmagic can also tell you if the plane was "hit" during the last flight (I think the receiver has to have failsafe feature for this function). I charge with ACE DDVC variable charger, at C/10 for 15 hours before flying. Several times a season I charge/discharge to measure the capacity using a SuperBrain 977. The only thing I don't like about this charger is the display clears 15 minutes after the cycle is over, so you need to be around to catch it. I would look into the Triton for my next cycle/charger. I've been warned not to use a fast cycle/charger for rx packs - better to go slow with something like the DDVC. The H9 Digital Servo/receiver current meter is handy too. You can check charger output, servo drain and other loads with it. If you're using NiMH, they seem to self-discharge much more quickly than NiCd (within a week or so). I stick with NiCd except in really weight sensitive applications. The NiCd seem to be more durable and tolerant. I've had switch harnesses fail. I use the heavy duty ones now, as well as heavy guage/gold plated extension cables.

Lock-out is a PCM failure. In a shot down generally the servos go nuts, banging from one full defelction to the other or fluttering all about. How about switch failure? Try sliding the switch to a partial position, will it stay of or off?

Mark and Seth, thanks for the very good suggestions. I'll check those out. Just reading these posts makes me realize just how much I don't know -- and should.

Mark, I tried fiddling with the switch (half position) but couldn't cause a failure.

Wow, I just looked over the info on the SR Batteries site (as well as the rcbatteryclinic site) and I have to say I'm totally overwhelmed! Man, and people say my dissertation is hard to understand!!!

So, Seth, would you recommend the 4-cell 800 series battery? I'm still looking at charger options. When I first go into RC I bought an inexpensive "peak charger" to charge the batteries that Hobby Zone Aerobird (that I supposedly bought for my son) used. Can I use that?

http://www.hobbypeople.net/gallery/130108.asp

I would size the pack to suit your airborne electronics and your flying habbits. I think the 800 should be fine for a day of scale flights with standard servo's, etc. in the Snipe. Obviously more is needed for large high torque servos in larger planes that are flown longer and harder. Larry at SR can certainly give you good advice here. The charger you reference has a minimum rate of 250ma which is C/3.2 (250ma/800mah), which I personally think is a tad high for regular use with a rx pack (it might make a good field charger at a higher rate, say C/1, if you have electric service at your field). I'm not an expert in charging and might be overly cautious, but for longevity of the pack, I'd skip the peak chargers and just trickle charge at C/10 for 15 hrs (80ma in the case of the 800mah pack). Sometimes I'll cycle faster for a capacity check, but regularly charging faster with peak chargers was "hitting 'em a bit hard" according to the folks at SR. It's fine for electric motor batteries (which generally don't live as long, and have ESC/BEC eliminator circuits to bring the plane down when the battery gets low), but not a great idea for rx packs which give you no warning when the voltage gets too low in the air.

All the advice given is good. I have also found that batteries like to be used week in and out. The ones that go bad for me are in the planes that sit around a while, like a couple of months. This last summer this happened to me; I did not fly that plane much and it has a pretty new battery pack. I have had to throw away about 3 packs that are only ca couple of yeas old recently. In the planes I fly all the time, I never have a problem. I am going to only keep a few battery packs and switch them in and out as painful as that is. I am checking mine out right now. I also find that fast charging batteries that are lower capacity( around 600 or less) hurts them.
Sorry about the plane. Someone at my field gave me a trainer he got at a garage sale. I changed the battery and reciever to my brand, took off trimming it out and the wing departed! Whoever built it added wing bolts but did not engineer it well; he butt glued the dowl mount on; nothing you could see inside to check. Glad it was just a trainer and no one was hurt.

I agree with Seth and Red Sholefield also agreed with this at one point (I don't know if it is at his website or not). NiCads are more robust, will stand being overcharged and sitting idle better then NiMH. NiMH loose charge fairly fast.

Don, I would use at least a 1700 ma pack. When a pack lays around it will tend to "false peak" when you try to charge it. So you need to use something to charge them slow and make sure they are fully charged. I use to have a device that would cycle the packs which was good because it told me how long it took to discharge the pack. It was good for weeding out bad cells. The charger I use now has adjustable amps and also a trickle setting. You should observe the pack when it is charging to get a feel for what is right also. You may see it "false peak" after a few minutes and you'll know it is not fully charged. I usually charge my 1700 ma packs at 3amps. The battery manufacturer should be able to recommend how to charge the pack. Just my two cents worth.

Lots of good solid advice here. Thanks everyone. Don't expect me to go electric anytime soon though!

CD ScaleDesigns Sopwith Snipe

Could you post any information you have on where you can get one of these kits.

Thanks!

Hi Jeff, the kit is currently only available through [link=http://www.cdscaledesigns.com]CD-Scaledesigns[/link] based in Germany. Look through our website and feel free to ask any questions you might have. Right now we are working on getting a US based distributor, but for the moment we send out our kits worldwide from the 'Old World' .