Red Beers

As I said in Tailskids thread I have joined the Ultra Stick 30CC club and instead of hi-jacking his thread I thought I should start a new one. Since I haven't built any big gas airplanes in several years I thought I would get recommendations about new products available. This plane is to replace my Giant Big Stick with a DLE35RA which had a switch fail causing the crash.

I should add that my wife and I retired and travel full-time in a toy hauler 5th wheel and the garage is my workshop. I get to visit some good RC clubs/fields but none with a lot of gas guys. Maybe I haven't looked hard enough for the gas guys. Many RV'ers fly but mostly electric.

Anyway in the other thread Truckracer pointed me to Hitec D645MW servos which I looked up. I found out they can operate on 7.4 lipo without a voltage regulator (one less thing to go wrong) so I've decide to go with those servo's.

Here's the current plan;

DLE 35RA
D645MW servo's
3 -7.4V lipo's, 1 for ignition and 2 for receiver.
DX18 radio
AR6600T receiver

Questions.

Most of my gas planes have 3 batteries and 3 switches. Does this systems have enough redundancy or are there better choices today? (the Giant Big Stick only had 2 batteries and 2 switches). In a prior thread Alan Hicks suggested I use 2 batteries and 3 switches, but what about 3 and 3?

Any other suggestions will be appreciated.

Thanks Red

Truckracer

My Feedback: (19)

Many possibilities here. First, there is really no need to haul around (3) batteries in an airplane this size. If you feel you need battery redundancy, I'd go with (2) LiPo or LiIon batteries of your choice fed into a Booma RC battery share pin switch. This will feed power to the receiver with (2) connectors. I would feed the ignition power directly through the receiver through either a Tech Aero or Rcexl IBEC eliminating the need for a separate ignition battery. Quick, simple, light weight (depending on battery size) and it works.

The above is my recommendation if you want (2) batteries. If it was my plane, I'd probably go with a single battery feeding power through one of the fail on electronic switches (Fromeco Badger, Futaba, etc. ) feeding power to the receiver through (2) connections. Again I would use the IBEC to feed power to the ignition. I prefer A123 LiFe batteries and find them extremely reliable. I'm comfortable with a single battery in smaller planes as long as there is adequate power wiring and a reliable switch. Battery connections are always Deans ultra or better. The Booma redundant electronic pin switch is a neat product.

Red Beers

Thanks Truckracer. I'll start searching those tomorrow.

ahicks

My Feedback: (2)

I see no fault with Truckracer's plan at all.

If this is all up for discussion though, if I get a vote, I think there's there's several decisions to be made by the OP. My thoughts:

First, LiFe vs. LiOn. My preference would be with LiFe for the fact I prefer KISS logic, and I wouldn't have to worry about voltage regulation or high voltage servos.

The second decision would be regarding the number of batteries. Call me a gambler, but I've learned to trust the LIFe batteries, and A123 brand in particular. The failure rate is so low, and they offer all the power I need - even if I want to power the ignition with that same battery. Some guys worry about this point (eliminating the ign battery), but there are SO many doing it successfully, it's hard to justify the extra weight/complexity of any more batteries than necessary.

Last, is regarding how to get that battery power to the receiver/power buss.The typical "J" connector and 24ga. wire are becoming choke points/restrictions for modern performance setups. Supplying power to the switch and receiver with just one set is restrictive, unable to handle the full capabilities of the battery. For that reason, I suggest 2 power leads from the battery, supplying power to 2 switches, both feeding power to the receiver, This also eliminates potential switch or connector failure bringing down a plane. Light weight, cheap, and well proven KISS logic. -Al

hawkerone

My Feedback: (11)

I'm flying my new Ultra Stick (32cc Turnigy) with old standard 6v NiMh on receiver and 4.8v NiMh for ignition. After $19K damage to garage I'm still not comfortable allowing LiPo's back on site, but that's another story. Suggest that you locate the two elevator servos in the forward cut-outs (under the trailing edge of the wing) rather than the aft ones where I did. I ended up adding 1/2 lb of lead on firewall as well as locating both batteries just behind the firewall to get it to balance. Balanced at 4-1/2" (115mm) behind leading edge made for a smooth flyer and a real dream to land. Couldn't be happier with this plane which by the way, generated a lot of positive attention at the field.

Red Beers

Al and Hawkerone, thanks for the responses. Yes this thread is for discussion. My last gas build was in 2009 and I'm wanting to use 2017 technology on this one. Looks like I need to spend some time in the battery section to learn about LiFE and A123 batteries. I have some brand new LiPo 7.4 1800's I was going to use...now I'm not sure.

Thanks again Gents.

Truckracer

My Feedback: (19)

+1, pretty much what I suggested in my second paragraph above.

All of my planes below 60 cc use a single A123 battery with a reliable switch (sometimes parallel switches) and multiple connections to the receiver. As Al said about himself, maybe I'm a gambler too but I just don't see the need to carry an additional battery in this size range. All feed power to the ignition from the receiver through an IBEC.

Red Beers

Ok it seems A123 are safer to charge, heavier and a little lower voltage.

If I use a A123 single battery with two switches for the receiver and ignition, what size battery do I need? How heavy of leads/connectors etc. And how do you power the ignition module? I suppose there is a thread on this topic, can anyone point me to it?

Red

ahicks

My Feedback: (2)

Most of the guys running LiFe are running 22-2500 mah.

Use HD switch harnesses, 24-22ga wire is what you are looking for.

Use both those switches to feed power to the receiver. If your receiver doesn't have enough slots to allow a second feed, there's a work around that works really well with an added bonus. You can install a "Y" harness between the receiver and any of the servos for that second feed. Most go for the rudder servo, to get a bonus straight shot for that servo under high demand conditions - straight to the battery, eliminating the need for that servo power to have to run through the receiver.

The TechAero optical switch get it's power from the receiver the way it comes (w/IBEC). The Rcexl switch, if you can solder, has an easy mod to be able to do the same. Directions to do that included. Stock, the Rcexl switch has a battery lead that needs power from somewhere. Could be direct to the battery or anywhere there is a red and black wire will work. It does not need to be switched as the only time it will pull power is when the ign. module has been turned on.

Truckracer

My Feedback: (19)

First, let me state this is only one way of doing things, there are many other ways that are just as effective. I'm sure you know there are many ways of doing things in this hobby.

First batteries, if you choose A123 there aren't a lot of cell sizes to choose from. For this size plane, I'd go with the 2300 or now more common 2500 MAH cell size that terminates in a Deans ultra connector. These are the same physical size. Wire size will probably be 16g or larger as thats just common for the way most companies assemble these batteries. I prefer a normal universal servo connector for a balance connection. These batteries are available from many sources including NOBS / Hangtimes Hobbies, WrongWay RC, Taildragger RC and many more. There is a wealth of info available at the Hangtimes website and I'm partial to their batteries though I have batteries from all the above sources and others. Hangtimes tends to be a bit more expensive than others but their assembly quality is near perfection.

http://www.hangtimes.com/nobsbatteries.html

Many companies offer the soft, poly versions of LiFe cells and these have proven quite reliable though in my opinion, none quite compare to genuine A123 cells. The advantage is lighter weight, lower cost and a larger variety of cell sizes and capacities. None seem quite as robust as A123 and though I own several of these poly packs, their cell life is proving to be a bit less than A123. Still far better than NiCd or NiMh!

If you are still leaning towards HV, consider the LiIon batteries from Fromeco. These are cylinder cells much like the A123 cells so they offer a safety factor over LiPo and these are very popular. Weights, physical sizes and costs similar to A123.

As far as switches, these days I'd recommend one of the fail safe, electronic switches such as the single Badger or dual Wolverine from Fromeco. These have been around for years and are extremely reliable. These days there are more choices and the switch available from Futaba is one I like and is much easier to mount in the fuselage.

http://www3.towerhobbies.com/cgi-bin...&I=LXEXZG&P=ML

This is a fail on type of switch so if the mechanical switch should ever fail, the electronic switch would turn on. This is pretty much how all electronic switches work including the Fromeco products mentioned above. Yes, these are all more expensive than a mechanical switch but they are extremely reliable. Note the Futaba switch has the Deans Ultra connector for the battery connection along with (2) power connections to the receiver. In most cases, you unplug the Deans connector and charge directly to the battery. Older Cell Pro chargers will charge through the balance connection.

Mechanical switches are still popular but it is a crap shoot what you're getting for quality. For years, I've made my own switches using a switch of the type used in the JR HD switch harness. Some planes have single switches though some have paralleled switches for redundancy. All use multiple connections to the receiver. I trust single batteries but not mechanical switches!

It is quite common these days to power the ignition from the receiver / servo power source. This is usually done using an IBEC / Ignition Battery Eliminator Circuit. Two common brands are the Tech Aero IBEC and the RCexl. Both just plug into a receiver port and offer ignition cut off via a transmitter switch among other features. I'll let the Tech Aero web site supply their features and I'm sure AHicks will be along to supply the advantages of the Rcexl. I'll just say here that both products get the job done! One is the Luxury Car (read that more expensive) version where the other is the economy car version.

http://www.tech-aero.net/ultra-ibec

Not sure if I helped or not. Others will probably say more using far less words!

Red Beers

First off a big thank you to Al and truckracer for the information and time spent on their replies. All comments are appreciated.

Battery - A123. Question. Is LiFE and A123 the same? I have the older Hitec H4 AC/DC charger that has a LiFE mode. Will that charge the A123 battery correctly or do I need another charger?

Truckracer

My Feedback: (19)

For our purposes here, LiFe and A123 are the same. Construction differs but charging is the same.

Red Beers

Gotcha.

Thanks

ahicks

My Feedback: (2)

To expand just a little (man, I can remember when I was trying to come up to speed on these when they fist came out!)

LiFe is a battery type/chemistry. Other examples of battery type/chemistries would be NiCad and NiMh.

A123 is a brand name - likely the most popular one.

So an A123 is an LiFe, but not all LiFe's are A123!!! (Kidding, you can ignore that sentence if you like....) -Al

Red Beers

Ahh! the lights getting brighter.

marksp

My Feedback: (9)

Here's my Hangar 9 Ultra Stick 30cc setup -

AR9350 receiver 9 (using all 9 channels)
(8) metal gear digital servos (throttle, rudder, (2) ail, (2) flaps, (2) ele))
Tech-Aero IBEC [ignition battery eliminator, isolation & remote fail-safe]
Spektrum 3,000 mAh LiFe Rx battery
Switch (on/off/charge)
gas engine
tank/filter

very simple, using modern, reliable & safe battery chemistry with IBEC. No need for the extra weight of additional batteries, plus the IBEC supports remote kill from Tx and/or mechanical Kill from manual switch.

ahicks

My Feedback: (2)

Mark, if you're planning on flying this plane hard, that single switch is not just a choke point for amperage delivery to your servos, it's a well known failure point that will bring a plane down. I wrote this up for somebody else recently. It's a plan that I've been using for a while now, because it eliminates the potential for either of those problems. It's not the only way of accomplishing this, but it might be one of the easiest.

" The plan is to get as much power as you have available out to your servos. With one switch feeding power to the receiver, you have a big bottleneck in the path from the battery to the receiver. Maybe not the switch itself, but surely in the size of the wire and the connectors.

If you add a second switch you can double the original capacity of that single switch - AND - kill any anxiety caused by a single switch powering the receiver. Erratic/bad switches is very likely the #1 problem when it comes to actual equipment failure bringing down a plane.

You would power the second switch with a second power lead from the battery. Easy to add if you solder, and 2 power lead batteries are becoming easier and easier to get already made up for you.

If you don't have room on the receiver to plug a second power lead in (coming from the second switch), you can accomplish the same thing using a "Y" harness in the line between the receiver and any of the servos. I generally use the rudder servo as it's the biggest, or if not, it's the one that will likely be pulling the most amount of power. Plugged into a Y like this gives it a straight shot to the battery during periods of high demand, without having to go tthough the receiver (another bonus).

This plan is well proven, light, cheap, simple, offers total power redundancy from the battery to the receiver and doubles the amperage available to the flight pack. No known down side."

-Al

marksp

My Feedback: (9)

Thanks for that!

I'm using a 8A continuous rated switch and am most certainly not an aggressive flyer (I realize that many fly this airframe 3D and some even couple the ailerons + flaps; not me). Adding a second switch is easy to do.

Cheers

Red Beers

Just got back from taking the wife on a little vacation...Now back to the project at hand.


[QUOTE=hawkerone;12317074 Suggest that you locate the two elevator servos in the forward cut-outs (under the trailing edge of the wing) rather than the aft ones where I did. I ended up adding 1/2 lb of lead on firewall as well as locating both batteries just behind the firewall to get it to balance. Balanced at 4-1/2" (115mm) behind leading edge made for a smooth flyer and a real dream to land. Couldn't be happier with this plane which by the way, generated a lot of positive attention at the field.[/QUOTE]

This comment got me to thinking and I wanted to run it past the guys here. I have a brand new Evolution 45 GX2 in the box that I never used. What if I put that on the plane instead of a DLE 35RA? One problem that might arise is the prop size being 21" for a 3 blade or a 22" for a 2 blade. But I own this one and will have to buy the DLE.

Red

marksp

My Feedback: (9)

IMHO, the DLE35RA is well suited for this airframe considering power, weight and prop size. The only issue I foresee is the rear exhaust may require some fairly long stand-offs. Notice the difference in length between my Saito FG-33R3 and my EP setup. The EP uses the included 20mm stand-offs. Had to aft mount the servos in the Saito build to compensate for the weight that far out front.

ahicks

My Feedback: (2)

I think it could be done, but the question for me would be regarding the personality of the resulting plane vs. the way it's designed, vs. what the result of the same plane built with a 30 or 35 up front might be.

One of my first gassers was a Giant Sportster with a Quadra 42 up front. Flew great so I flew it quite a while like that. Then, in a quest for a little more performance, I replaced the Quadra with a DLE 30. Yes, it still flew great, but with the 2lb+ difference in weight, the plane's personality was transformed into something much more "sporty". Lesson that was reinforced? Lighter flies better, still! -Al

Red Beers

Update... A123 battery and Aero-tech IBEC on the way.

Does anybody have any experience with this switch? http://www3.towerhobbies.com/cgi-bin...?&I=LXFBNL&P=7

[h=1]RC Gear Shop Heavy-Duty Switch[/h]

ahicks

My Feedback: (2)

Yes, though sharp looking and practical, there are 2 downsides. First is the type switches it uses. They're contact type - like a set of points in an old car or lawn mower, unlike the self cleaning action you get with the much more reliable slide type switches. Potential for bad/erratic performance far greater with this type switch.

The second thing is some have reported failure of the wires on the back of the switch, due to the fact they are unsupported.

Red Beers

Thanks Al.

Red Beers

Got the DLE35, D645MW servos, an A123 battery, Aero-tec IBEC, MPI switches, and 18X10 Xoar prop in hand now. I upgraded to a 9030T receiver.

Here's my next question...I have a Hi-Tech H4 AC/DC charger and it looks like it won't charge a LiFe battery. So what chargers do you recommend?

Thanks Red