2.4 ghz flying experience

[bill bischoff]

Today I flew Mike Greb's MO-1 with the 2.4 ghz radio. As stated elsewhere, the current scheme involves simply holding the car style transmitter in the left hand, and the flying handle in the right hand. When I watched Mike fly it, I noticed that when he would let off the throttle, the engine would go to an excessively low RPM. Before I flew it, I ran the throttle trim all the way up so the idle speed was faster, and this seemed to work better. I also noticed the radio would glitch occasionally, but it realized that it had to do with how I was holding the transmitter. When I let my left arm hang at my side, the tip of the transmitter antenna would point at the airplane. Since the antenna radiates from the sides and not the tip, the radio would lose signal. As long as I held the transmitter in a normal upright position, everything worked fine.

Overall, I can't help but think that this will be the future of carrier. Flying with the throttle in the left hand took a bit of conscious effort, and I wished the trigger had a bit more range of movement, but considering I only flew it one time, I felt reasonably comfortable almost immediately. I am modifying my own transmitter to mount on a handle so that I can use both hands for high speed on scale class airplanes. Once I get it done I will post it. The good thing is that Mike and I are using the same type of radio, so we can bind our airplanes to either transmitter and see what we like better.

[eric david conley]

     Interesting Bill, I'm glad you posted this. I bought one of the ground transmitters and took it all apart to see if I could build a handle that wouldn't be any bigger than a J-Roberts 3 wire handle with the antenna coming out where the throttle pole is located. Well in taking the original handle apart I ended up with a whole lot of "stuff" which only a small part was the transmitter, throttle trigger, and antenna. It was all those other parts, servo reversing switch's, trim switches, and I think some kind of end point adjustment plus a charging plug receptacle. Looked like I had pulled up ac 5 pound morning glory. So I ended up giving it away to a fellow that wanted to do the same and wasn't phased out by all the "stuff".
     I was going to use it in scale and hadn't thought a lot about using it for carrier. I did think it might temp someone who might want to get into carrier but didn't want to use the 3 wire equipment that we use. So I'm looking foreward to how you do setting your system up.
     On a side note, we had a RC flier stop by the club flying site and asked about getting back into cl as that was what he had started with. So we told and showed him every thing we could and a couple of weeks latter he came back with a plane (I think it was a Skyray) that he had installed a battery, electric motor, receiver plus ESC and he proceeded to fly it much to our dismay. We asked him why he went electric and used a 2.4 and he said that he had all of that stuff already so it was easy for him.
    So about a month latter he was back with a combat plane that one of our guys had given him and it was set up the same way. I asked him why he did it to the combat plane and again he said because I have every thing to do it with. Sooo, it was the combat flier from our club that called me about my ground transmitter to see if he could get it into a handle. He wants to try electric in combat also but doesn't like the transmitter box hanging around. All their using the 2.4 stuff for is to start the motor and set the throttle. This is the reason I want to see the 2.4 thing get approved. I think it will ease the way in getting back some of the guys that left CL to RC.  Eric

[bill bischoff]

I was going to wait to post pictures until I had the handle finished, but here 's a few "mock-up" pictures. My transmitter has a flat area below the steering wheel, which gives me someplace to attach a regular handle. I sawed off the bottom half of the transmitter, and will bolt the top half to the flying handle. There will be a battery holder velcro strapped to the bottom of the handle when all is said and done.
 
As for your combat guy, it sounds like he doesn't need a radio, just a timer/ controller to drive his ESC. Go to horizonhobby.com and look up EFLA172. Should be all he needs.

[bill bischoff]

Of course, even if this works I will continue to look for smaller and/or easier ways to do this. I have some ideas, and we have some customers who are radio and/ or electronics wizards!

[Joe Just]

Well, all this has my ageing heart beating rather quickly.  I am, with help from those with far far more experience with stuff R/C than I will ever have, I am beginning to gather all the stuff i need (I think) to give this 2.4 method a try in Profile.  I am rather hindered with the closest hobby shop nearly 70 miles from here, so I have been relying on the "Net' for help. To my ever last gratitude, I am getting fedback to my stupid questions and I think I will somehow get all this mystery solved.  The only rather firm idea I have is to build a transmitter 'tray" that will be supported by straps over my shoulder and neck to give the transmitter a solid base to work from.  I can't say for sure that this will be the best thing since rubber tennis shoes, but because of my condition i need all the solid foundation I can get. I get a laugh or two thinking that all my research, dreams and help will get me in the air just about the time some manufacturer like Brodak will come out with a "Plug and Play" system enabling any of us bumblers to get a 2.4 system installed and flyable in less time that it will take to read this message.

I am in touch with many many Carrier guys, and in most cases the responce to giving throttle control with 2.4 and eliminating the third line is very positive.  The feedback I'm getting from the traditional top guys is that they will continue to use the equipment they have on hand to compete as they have in the past.  As Eric has pointed out using 2.4 has some definite weight disadvantage as well as the increased wire diameter's that will also
be a hindrance.  Enough said. Let's hear it from the rest of you guys.
Joe

[Tim Wescott]

As for your combat guy, it sounds like he doesn't need a radio, just a timer/ controller to drive his ESC. Go to horizonhobby.com and look up EFLA172. Should be all he needs.

Stories abound regarding flying CL on a timer when a prop strike happens -- the bottom line is that most ESCs (even the Castle ones) don't seem to be up to the job of shutting off the motor in a crash.  So the timer has to do that.  Keith Renicle's timer is gaining a reputation for being the safest way to land a plane prematurely and not fry the ESC and possibly the motor and battery to boot.

[Tim Wescott]

I have four thoughts that just bubble to the surface on doing control at the handle.  These are all very superficial, so don't get your wind up if you know they don't work -- just say so.

Thought 1:  You probably want to get the plainest 2.4GHz transmitter that you can.  This probably means the cheapest one that JR or Futaba makes, as you'll get the reliability of a name brand, and the lack of bells and whistles that comes from getting a loss-leader.

Thought 2:  There's a company that's making add-on 2.4GHz modules for older transmitters.  It's called AnyLink: http://www.tacticrc.com/tacj2000.html.  It works with transmitters with trainer cords, which means that it just needs a correctly formatted pulse train.  This means that you should be able to get by with a battery, one of those modules, and a gizmo that makes a pulse train.  There's a good chance that Clancy Arnold's system would provide that pulse train, but I guar no antees.

Thought 3:  You remove just the throttle pot from the radio, extend the wires about 5 feet, mount it on your handle, and keep the radio clipped to your belt.  You'll have to deal with the dangling wires, but it should work.

Thought 4:  Similar to thought 2: if any of the current radios put a plain old pulse train over their trainer cord interface, then a pulse train source at the handle, with a cord down to a transmitter on your belt, will work.

[Douglas Ames]

I would think the throttle sensitivity could be tamed with ratio changes on the servo arm,
 or an aftermarket slider pot with a longer range of movement.

[Fred Cronenwett]

I have flown with the Bill Young handle that looks almost identical to the 3-line handle and currently fly my models with a transmitter hooked to my belt. Everyone prefers something different, I like the transmitter on the belt and have no problems operating the throttle with the left hand and fly the model with the right hand. Others prefer the throttle control on the handle, use what is best for you.

Also consider this.... I have 5 models that use the same transmitter. If you have a special handle you have to adjust the handle each time to switch it from one model to the next. All of my models have thier own set of lines, but all 5 models use the same transmitter.

What I like the best is that you get nuetral elevator adjustment with a stunt handle. By having only one set of lines per plane I never have to adjust the handle for nuetral handle adjustment.

I am currently flying two models with 2.4 Ghz controls with no issues.

Fred Cronenwett

[Bill Little]

Sounds like 2.4 will be the way to go in future Carrier and Scale endeavors.

BIG Bear
RNMM/AMM

[eric david conley]

     Bill,

     I see you are using a surface transmiter and one that looks like it will fit well on top of your handle. This is the set up I am considering also because I'm so use to doing everything with one hand and want to keep it that way. I have a few questions that you may be able to ansewer. I have noticed that the antennas are different between the air RXs and the surface RXs and was wondering if these units will work ok in out planes? I'm thinking that you cant mix air and surface equipment unless you really know what your doing. I've been looking at the different surface TXs and have found a few that look like they may work on the top of a CL handle but one thing they all seem to have in common is a chin bump out in front of the throttle trigger which right away makes them more difficult to mount over a CL handle. Is that bump just a stop for the throttle trigger or is it full of "stuff"?
     One TX that I think may work is a Spectrum SPMR 2400. It is fairly flat on the bottom and then sweeps up toward the rear so that the hand could be positioned a little bit higher in the CL handle portion (just thinking).
     On another note, we asked the RC guy why he didn't use a timer and he said he didn't have one and had never used one so he used what he had. Again this is OK because at least we hooked him for now and if he sticks he will probably use a timer who knows but it was his way of getting into CL quick and dirty so to speak. I hear so many CL fliers that are so against RC say if they want to fly CL they need to do it without the RC thrown in. I know a lot of CL people that concider the RC group crap as a whole and I know some RC people that think we are a little simple, the RC people that I know don't have animosity against CL. Just my thoughts, Eric.

[bill bischoff]

What you will run into is that all the different 2.4 ghz radios seem to have their own "language". Receivers and transmitters won't simply mix and match. You must have the proper receiver. When looking at the receiver antennas, note that many receivers will look as if the antenna is 4-6" long. The fact is that only the last inch (or so) is actually antenna. The rest is simply a shielded extension. The idea is for the two antennas to be separated from each other enough to "see" around obstacles in the plane, such as engines, motors, or batteries. For our purposes, even a car receiver with a single antenna should be OK, as long as the antenna is not directly pointing at the pilot or transmitter. Since the Spektrum car radios should talk to the DSM2 air receivers, I'd use the $30.00 4 channel air receiver, or the 6 channel park flier receiver if size and weight are critical.

I am going to look at the Spektrum DX2E when we get them back in stock (end of the week). It is a low price, low frills radio that may not have too much stuff inside it. Plus, it's only $60 WITH a receiver.

Whether or not the "chin bump" has stuff in it, all I can say is you'd have to open it up and see. I suspect in most cases it is there as a trigger guard more than anything else.

And say what you want about RC'ers, without them we wouldn't have this stuff!

[Fred Cronenwett]

I am using a JR transmitter (older DSC unit) that I converted to 2.4 with the tactic "anylink" 2.4 ghz adapter, this unit converts the older style transmitter to 2.4 ghz and it has to use it's own reciever. I can not buy just any reciever, other recievers will not work with this sytem.

Futaba has two types of 2.4 systems, you have to get the right type of reciever to go with the transmitter you have. Look on thier web site and you will find the two different systems.

Fred

[john e. holliday]

So all we need is one transmitter?  Then we can buy as many receivers as we need?

[Tim Wescott]

<snip>

I hear so many CL fliers that are so against RC say if they want to fly CL they need to do it without the RC thrown in. I know a lot of CL people that concider the RC group crap as a whole and I know some RC people that think we are a little simple, the RC people that I know don't have animosity against CL. Just my thoughts, Eric.

I get very little animosity from the RC guys I fly with.  I get some honest puzzlement, some "wow, I did that as a kid", but little flak.  The only "animosity" I get is from a flying buddy, but that's honest teasing, and I started it anyway by teasing him for being a civil engineer ("you guys just know how to dump gravel on the ground", etc.)

[bill bischoff]

Doc, one transmitter will work an unlimited number of receivers. Some transmitters have computer memories for setup parameters for multiple models, for things like servo direction and amount of servo movement, but even non-computer transmitters will talk to as many receivers as you want to own.

[john vlna]

I’ll be trying some planes with 2.4ghz control this weekend. I bought two systems, one for cars and one for planes. The car systems has a 2 channel Tx, and a 3 channel Rx. The air system has 6 channels. It is rather complex, requiring computer programming. The problem with bargain systems is that you don’t get a lot of information up front. All I received was a TX and RX. I have had to down load everything else, even a manual, and had to order a special usb to Tx cable. I even had to download software to read the manual.  It might work without programming, but I haven’t checked it yet. So all flying will likely be with the car system.

It will be easy to use on different planes; all I have to do is switch the Rx.. Since I will be flying electric powered models no servos will be required. The receiver only weighs 19 grams, essentially adding no weight.

[Fred Cronenwett]

I have one transmitter that flies all of my models and it has "Model Memory" that retains the settings for servo reversing, end point ajustment and other settings.

End point adjustment controls how far the servo moves in the two positions, very handy when setting the zero position for flaps.  Each model has different settings and it retains model 1, 2, 3 and 4.

each model I fly has it's own set of lines and handle, but all use the same transmitter.

Fred Cronenwett

[john vlna]

The air system i bought will also store different model setting, I don't know how many, it just says numerous in the manual. It is probably an overkill for me. Most of my models will only throttle.

[john vlna]

I flew two planes using 2.4 today. Both were electric. It took a little time getting comfortable with the throttle in my left hand, but after a while it seemed to work as well as a handle with a trigger. I still think I would like everything on one handle. Both planes were electric powered and I used the car system. The Tx's trigger is spring loaded to stay at mid throttle. The is a no-no for electrics. The esc's are programmed to start at low throttle only. With electrics you need to calibrate the Tx pulse range to the esc. Because of the spring loading this is a two man job. To insure the trigger didn't go to its mid position accidentally, I used a rubber band to keep it in place. If the model was using a servo to run a glow throttle this would not be a problem. For electric motors I think I will prefer a normal air Tx. Interestingly both planes maintain the 60 degree position with almost no throttle changes at the midpoint. If I had been able to get to the trim, a two handed job with the car system I could have flown low speed just using the trim pot.

[bill bischoff]

John, there's no reason you couldn't take the spring off the throttle trigger and fly that way. Also, check your transmitter for a "neutral shifter" on the trigger. Many of them have a mechanical switch to set the neutral at either 50/50 (equal fwd/reverse for cars with reverse) or 70/30 (more fwd than reverse, for cars with brake rather than reverse). I understand how the ESC needs to see full high and low to arm properly, but I would think you don't want the motor to totally stop when you release the trigger. Taking the spring off the trigger may be the best way to go. Plus, you could always put it back on if you wanted to.

I've got my transmitter handle almost done, and plan to try it next weekend. I'm thinking that for new people with  profiles, just having them hold a car TX in their left hand will be the easiest way to get them started. They will actually have the advantage of not already being accustomed to the standard 3 line handle.

[john vlna]

Bill,
Yes I figured the spring could be removed, I don't see any external way to change it. This is a pretty cheap system. I have been flying electrics using insulated lines with a custom handle . The throttle stays at whatever position I leave it at. Basically I fly the electrics just like the glows. My finger is never off the trigger. my handle even looks like the Brodak/L&R/GS/Roberts handle. My plan is to take the thing apart and make a custom handle this winter. Till then just fly and have fun. I also have the air system to set up.

[Joe Just]

Well, got all the needed parts for giving 2.4 a try.  Because my learning curve at 75 is rather slow I decided to make a mock up board with everything placed on a 24 x 24" ply board.  Mounted the engine yesterday. Today I got up enough nerve and placed the reciever, battery box and servo in place. Made a short wire with 2 "Z" bends and connected it to the servo and the throttle arm.  Turned on the transmiter and then the battery and gave the trigger a pull and................IT WORKED!!  With everything hanging out in the wind is one thing, but putting it all together in a plane is somthing else.  I'm still a little confused about how to mount the servo, but am mentally trying to work that out.  HEY, IF THIS OLD GUY CAN DO IT............ANYBODY CAN!!  Cost so far about $75 not counting the battery cost as I have many that I can use already. I may make the pushrod from a section of threaded 2.56 wire with two clips to made adjustments to the throttle a bit easier.

The best part of today was to ask my wife to come out to the shop and see what I did!  She smiled when the throttle opened and closed by using the 2/4 radio and looked at me and said..."Wonderfull!  I no longer have to help you set up a thrid line by standing at the  plane's engine and yell "open" or "Closed" anymore!!  I guess you would have had to be here with me in the past to really get the humor of that phrase.
Picture tomorrow. I'm just too tired now.
Joe

[john vlna]

So does anyone know how the voting to use 2.4 went. The AMA site has not posted anything final that I have found and I thought they were voting last week

[bill bischoff]

The contest board procedures document said the votes were due by 9/15, and results would be published by 9/30.

[bill bischoff]

Here's my finished handle, and a couple pictures of a Spektrum DX2E transmitter. This is a basic, non-computer 2 channel radio. I think it will have a lot of merit for several reasons. First, it is inexpensive, but still a national name brand ($59.99 with receiver). Second, it is simple and un-intimidating for novice radio users, and third, it would be quite easy to cut off the handle and chin bump and have a large flat surface to mount atop a handle if you wanted to go that route.

The more I think about it, the more I am thinking that for novices we should promote the idea of just holding the transmitter in the left hand. They don't have to "un-learn" the feel and technique of a 3 line handle, and being able to use the radio just as it comes should be attractive.  We've already seen that having the transmitter in hand when starting the engine is more convenient, too. And since novices will typically be starting with milder performing profiles, there shouldn't be any need to hang on with both hands in high speed.

I suppose time will tell what the preferred system will be...

[john vlna]

Bill
Nice conversion, I am curious, your battery pack does not look like enough cells. Any TX I have seen uses nominally 9.6-12v. The pics look like a Rx pack
John

[bill bischoff]

More and more of the 2.4 ghz radios are being designed to run on only 4 cells. I believe some will also run on a 2 cell lipo. A 2 cell 800 lipo, like the one on a Blade CX helicopter, would fit this handle very nicely, be light, and easily run all day. Trouble is, this particular radio would need a regulator to keep the voltage below 6 volts.

[eric david conley]

     I'm impressed, with those so nice and tidy bends you made in the aluminum strap you used to make the handle. I've purchased one of those Spektrum DX2E transmitter receiver packages and have cut the handle off of the transmitter so am ready to mount it. How did you make such nice and precise bends in the aluminum strap? Did you put the wood on the front strap to make it stiffer for some of the heavy pull tests we get our selves into? I'm so use to the fixed lead out lengths on the J-Roberts stile handles that I was just going to put two I-bolts 3.75 inches apart on the front strap and use connectors to adjust my line length.
    I think your right about someone just holding the transmitter in his other hand while flying the plane with his predominant hand. I see quite a few carrier fliers using both hands (one for the throttle) with the J-Roberts handles. I don't seem to be able to do it and don't want to take the time to retrain my brain right now so will go ahead with the unit that you have built. Eric

[bill bischoff]

The 3/4" aluminum and the 3/4" oak furring strip came from Home Depot. The aluminum was simply hand bent in a bench vise, then the wood parts were made to fit. The front portion of the front grip is an additional hand hold for hard pulling airplanes. The rear piece of wood on the front of the handle is the adjusting mechanism and cable guide. Without it, the cable would make sharp bends where it passes through the aluminum frame. The cable passes through a hole drilled in a 10-32 brass screw. (I used brass because it was easy to drill) The brass knob also came from Home Depot, out of one of the specialty hardware drawers. The cable is actually nylon coated steel for tennis racquets. Since I own a Nicopress crimping tool from my days as an aircraft mechanic, it is easy for me to do the swaged ends on the cable.

[bill bischoff]

I got a wealth of experience today flying my Zero with a 2.4 gHz throttle. First, I flew with my transmitter handle, and the very first thing I learned was not to use a dry cell battery holder on the airplane that was not fully enclosed. One cell kept coming loose, which would of course shut off the radio. Since I live near the flying field, I made a quick trip back to the house and cobbled up a light ply cover for the battery box. It did its job, and the rest of the day there were no more battery issues. My impression of the transmitter handle was that while it worked as planned, it seemed rather cumbersome, and as I think I mentioned before, I would have preferred more trigger movement. The radio I used for the handle has a mechanical switch for the throttle to shift the neutral point from 50% fwd/ 50% reverse to 70% fwd/ 30% reverse. I found that with the 70/30 setting, I never needed to push the trigger to "reverse" except to land. I also observed that not having the radio nearby when starting the engine was inconvenient, and resorted to starting the engine with the radio off so we could move the servo by hand. Speaking of the servo, on the next airplane I will put it on the inboard side of the fuselage to keep it clean. Let's just say that this servo will never rust!

Next, I wanted to try flying with my Spektrum DX2E radio, held in my left hand. As seen in the photo, I simply double sided taped the Spektrum receiver to the airplane, since my other receiver wouldn't communicate with the Spektrum TX. I found that I preferred this setup. The Spektrum TX has more trigger travel, giving a better overall feel. Also, it was much easier to start the engine with the TX in hand. My only complaint about the Spektrum TX was that the  throttle was set up for a 50/50 neutral instead of a 70/30 neutral position. I put a light rubber band around the trigger and front of the TX to pull the trigger to low idle, and found this to be a very useable solution.

I am now torn between using the Spektrum radio as-is, or making it into a transmitter handle. The "brain" of the transmitter is smaller than the one on my current transmitter handle, and the throttle feel is better. It may make a more satisfactory transmitter handle. On the other hand, there is a lot to be said for using the radio just as it comes. Maybe if I win the radio in our raffle next month, I'll be able to do both!

Once again, thanks to Phil Dunlap for helping me out with this today. We had an absolutely beautiful day today, yet we were the only two people at the flying field.

[Douglas Ames]

<snip>
 Since I own a Nicopress crimping tool from my days as an aircraft mechanic, it is easy for me to do the swaged ends on the cable.

Aaah, but do you remember the crimp sequence?  =[2-1-3]=
I remember that being an A&P test question.

I realize your converting your Zero to 2.4 Ghz, but could the Rx and battery fit in a rib bay in a future build? Is there room?
The mini servo looks good! Gotta try this!!

[john vlna]

I’ve flown both the car and air systems with several different planes. All attempts have been with the TX held in my left hand. I prefer the car system, but really would like everything on one handle. I have found it trivial to change the Rx from plane to plane, I simply Velcro the Rx to the plane. Since all my flights have been with electrics I don’t need to worry about a battery, the models are already set up with a battery. Power to the RX comes from the ESC’s  BEC.

One thing I don’t like about my air system is the narrow range of the throttle. It only has a variation of 1.2 to 1.9 msec on the throttle channel. This may be something that is programmable, but I haven’t explored any program options yet. I am using the system with the factory default setting. The car system has the full 1-2 msec of range. Both systems have a solid signal connection, no dropouts or any other reception problems

For me the next step is a prototype handle, probably similar to Bill’s

[bill bischoff]

I realize your converting your Zero to 2.4 Ghz, but could the Rx and battery fit in a rib bay in a future build? Is there room?
The mini servo looks good! Gotta try this!!
[/quote]

On a new install, the battery will be in the outboard wing to serve as tip weight. The receiver will either mount in the wing center section, or through a cutout in the fuselageThe servo is a Hitec HS65MG. Complete overkill, but I had it. On a new install, I will probably use a Hitec HS81. Still overkill, but I don't know how the gears on a sub-micro servo will stand up to the vibration of an IC powerplant. I'll take the small weight penalty for durability.

BTW Doug, don't forget our contest in a few weeks. We're having a raffle, and every official flight gets a ticket. You could win the radio!

[Joe Just]

Bill and all..........I wonder about putting the battery pack out near the end of the OB wing.  I purchased a pack with an off on switch added the 4 baterries (AA) and the weight of the assembly is just under 5 ounces! For right now I will be placing the battery pack as shown in Bill's pictures.  Because I have mufflers on all my Profile ships I still plan on keeping the servo on the OB side of the fuse.  I am still in the very first learning part of the learning curve, so I need to approach all this, new to me stuff, with caution.  OBTW...Thanks to all for all the NEEDED help.
Joe

PS  (John. see, I can be in a mood to try something new)

[bill bischoff]

Funny, I was weighing batteries this morning...If you put the battery in the outboard wing, but half way to the tip instead of all the way to the tip, it will act like half as much weight. You can position it anywhere in the outboard wing to get the desired result. If you mount it on the fuselage, you will still need to add tip weight. Why not save the weight of your normal tip weight by putting the battery SOMEWHERE on the outboard wing?

FWIW, a JR 4 cell 700 mAh Ni-Cd pack weighs 3 oz. I think this will be my starting tip weight on a new airplane. As a bonus, the batteries can't come apart!

[john vlna]

Bill, Joe,
Many of my electric CL models are set up with the battery on the outboard wing. However my carrier models (profiles) have the batteries close to the fuselage. I threw  a battery off once during high speed so I now mount them very securely to the fuselage. These models still use tip weight. I see no reason why you couldn't do it either way.

John

[Joe Just]

For those that may not feel comfortable in starting a new phase in Carrier take a look at the approach I'm taking.  I know absolutly nothing about R/C, so I have to start from groun d zero.  here's the test board I made.  Today I tried it out with the engine running and guess what?  IT (2.4) REALLY WORKS!  More testing and learning, but now I feel like I am off zero, perhaps only to #6 out of 100.  I tested the throttle control form at least 90 feet away. No Problem.  I still need to learn how to fasten the servo better.  See attached picture.
Joe

[Douglas Ames]

Weight X Arm = Moment.

ex. - So if your wing panel was 18" c/l to tip weight, and the tip wt. was 2 oz., that's a moment of "36".
Your batt. packs weighs 5 oz's and you want to replace the tip weight just back-figure it. 36 / by 5 = 7.2" outbd. from the centerline of the fuse. The less difference in tip vs. batt. weight would put the batt. pack further outbd.
Rudder offset would be nil and unneeded I think with that much weight?

[john vlna]

Doug,
Your logic seems sound, in practice the planes I have which depend on battery for tip weight don't seem to have to be that far out. Again they are not carrier planes so it might change a bit. For the carrier planes the batteries are close to the fuse, on the outboard side, even so I use less tip weight, but there is some.
john

[bill bischoff]

I just had a eureka! moment today. I've been going back and forth between making my Spektrum DX2E into a transmitter/handle, or using it stock. It finally struck me that even if I build it into a transmitter/ handle, I can still use it as a stand alone transmitter in conjunction with a standard two line handle. Duh!

[eric david conley]

     Bill,

     This has to do with your reply #30. I'm using the DX2E and was trying out the throttle throws and question the way the throttle works in the DX2E. Keep in mind that I'm trying to use push for speed/pull for LS. I find my tx throttle trigger seems to be a 70/30 with the 70 at the rear (towards the handle) and 30 towards the chin bump. When I was working the throttle with my e-109T I noticed the motor didn't seem to be throttling up as much as it should and after a while I pushed the the throttle forward (the 30%) and the motor went to full power (what happened to reverse)? So what I have is a 100% throttle response from stop to stop but with a neutral spot at 70/30. Also at that 70/30 point my finger goes from pulling pressure to pushing pressure for the remaining 30%?
     I'm thinking I can work with this "BUT" it means I will probably be hanging in the 30% portion so instead of pulling to throttle back I'll be releasing, and to throttle up I'll be pushing (quite a difference in throttle feel). Directions are the same but feel very different. When I finally use it I will report back with the out come.
     I've been rushing this project along so I can fly it this coming week end at the Hi-Johnson meet in Southern California. I don't do to well in rush mode and ruined my first radio by reversing the power lead (I'm guessing this is what did it) so not taking any chances now. I'm hoping to fly it by Tuesday so I can get some practise in before the weekend.  Eric

[bill bischoff]

Eric, put a light rubber band around the base of the trigger and hook it over the front of the transmitter. It doesn't take much tension to override the spring on the trigger. Then you will always be pulling, not sometimes pulling, sometimes pushing. I plan to eventually take mine apart and see if there is some way to modify the trigger mechanism to avoid the need for the rubber band, but for now it's working fine.

 Even though I normally pull the trigger for slow, I have been flying with the transmitter in the pull to go fast direction. Somehow this doesn't seem foreign on the transmitter, although when I fly a three line handle set up that way, it takes a bit of conscious effort. I had intended to try reversing the throttle on the transmitter today, but just plain forgot.

One bit of information about the throttle trim on the DX2E: It only works when the trigger is in the neutral position, and has no affect at either end of the trigger travel. This makes sense on a car so you can trim your idle speed, but for our purposes it makes the trim useless.

[Randy Bush]

If your transmitter has "end point adjustment" (or similarly labelled programming feature) on the throttle channel, that might help get the idle and servo travel that you want.

If there is a "rate adjustment" or "travel volume", that should allow you to vary the sensitivity of the trigger -- that is the amount of movement of the servo in relation to the trigger movement.

Randy

[bill bischoff]

The DX2E is a non-computer transmitter. It has a rate adjustment for steering, but not throttle.

[eric david conley]

     Took my e-109T out this morning and made 2 flights with the 2.4ghz tx and rcv. Everything went just like it should have. Some of the things that stand out; Those 2- .021 lines are heavy, 2.8 ozs verses the 3-lines of .015 at 2.3 ozs. It is real noticeable during slow flight where they sag and seem to pull the inside wing tip down a little bit. While using the handle for up and down (LS) and working the throttle things seemed more positive, no lag or cross over between the two, like they were two separate actions. I noticed my motor seemed to have a little more power than when I was running it through the linear-taper potentiometer also seemed to use less battery for the overall flight?
     The Spektrum DX2E transmitter and receiver cost less (4 cents less) than one 3-wire handle and also eliminated the linear-taper potentiometer and signal generator so to me it seemed simpler overall. My only concern today was dragging the handle/transmitter through the grass when I was returning the plane to my stooge. We will see how it goes over a longer period of time, for now it was a pleasant happening.  Eric

[bill bischoff]

A pair of .021's does contain about 30% more metal than a trio of .015's, but according to some numbers on the NCLRA line rake program, the .021s have less drag. Even with a bit more tip weight, your high speed should be no slower, and maybe a bit faster. Of course the rule is .020, not .021, but .020 seems to be a non-standard wire size. I wonder if as a group, enough of us would be interested in some .020 stranded lines to make it worth special ordering a batch from a wire manufacturer. I discussed this with Melvin Schuette of MBS Model Supply previously, and I seem to remember that the  minimum order was a lot less than I would have expected. Perhaps Melvin will chime in with more info. I don't know how much difference .020 vs.021 would make, but if we can buy .020 at a competitive price, why wouldn't we?

BTW Eric, how about a picture of your new handle? You can say it's Pete's if it makes you feel better, like they did in Model Aviation.

[Joe Just]

There are .020 lines in bulk on Ebey. Cost about $20 for 250 feet with no postage charges.  Wire is excellent in quality.  The company ships quickly. Check it out.  There may be a better price out there for 1000 foot rolls, but for those of us that only ned a couple of sets to get started these are fine.
Joe

[john vlna]

Joe,
Thanks for the line info.
Bill, Eric
Attached is a copy of my handle. I know I showed it to Eric but don't think I showed it to you Bill. I built the first one about 10 years ago for servo controlled throttle using Clancy Arnold's electronics. That one only had the variable resister in the handle. About four years ago when I started to fly mostly E powered models I put all the electrics in the handle. I would like to do the same with the 2.4 stuff, but it may be more work than is necessary. I am still on the fence . After the flying season slows down I look at it.

John

[eric david conley]

     I meant to attach some pictures and forgot. I could have just said "see above" as how many twist and turns can be made mounting a transmitter on top of a cl-handle. I mounted a battery box that I got at radio shack to the bottom of the handle. I mounted a back stop for the throttle trigger which also keeps my middle finger from interfiring with the throttle trigger when I'm pulling it back to stop. Used rubber bands to pull the throttle trigger full forward so now I have a steady lite pull from full throttle to idle and then stop, your a genius Bill. I used some 8/32 finger head bolts for my line attachment points. When I made my new lines they came out perfect so was able to use the same size line connectors but if they hadn't I could have used different size connectors to even them out, keep it simple I like.  Eric