Episode 6: What Can Your Transmitter Do for You?

[00:00:06] Welcome to rc plane lab a podcast for anyone interested in rc airplane we'll share tips and tricks on how to build models and talk about successful flights epic crashes and everything in between visit us at rcplanelab.com to sign up for our email list and to ask us questions you can also text us or leave us a voicemail at 818-351-9846 please help us out by rating and reviewing us in your favorite podcast app thanks for spending time with us today now here are your

[00:00:35] Hosts ron and tom hello everyone and welcome to the rc plane lab podcast i'm ron and i'm tom today we're going to be talking about transmitters but before we get to that tommy have you done any work since last we spoke on anything yeah a little bit i covered the rudder okay well you did get something done good good for you i was hoping

[00:01:02] You weren't going to bring that up yeah i got there got the rudder done it's all covered i'm almost ready to start installing everything back in the airplane yeah well i've got to say it's

[00:01:13] Looking really good with the decals you have cut the iron crosses turned out really great thanks

[00:01:18] Had a good buddy to cut those for me yeah he must be pretty pretty handy with the with the

[00:01:23] Vinyl cutting machine no it's it's fun doing that kind of stuff for airplanes i i enjoy the decal work and and all that stuff i i think it's fun and they really do look good for those

[00:01:35] Of you that don't know but it's an old stick airplane that ron cut the iron crosses for me and we actually decided that we liked the outline on the old iron crosses instead of just being a black cross it's a black cross with a black outline looks really good yeah it gives a little depth i like it yep unusual colors too that i chose for this airplane not the usual red and white stick

[00:02:00] It's something a little different yellow and transparent orange yeah which transparent orange does nothing for me but it's the transparency in general i get it yeah i don't like to see the no it's not and that's why it's your plane not mine exactly so since last we spoke i did get a new to me airplane nice it's a great planes twin star so dual electric motor oh the electric version yeah okay okay i gotcha it so i took it out actually a couple days ago after i got it

[00:02:36] Bound up to my transmitter and stuff and and maidened it if you will like i said new to me plane oh that was scary i actually thought i was going to lose it a couple times do tell it was very off like i i did all the checks the pre-flight checks and stuff before i took it out there i made sure everything was on made sure the propellers were balanced made sure the gear was tight made sure all the connections were were good but there was just something off when i when i was flying it it's a faster plane than i prefer i expected it would be a decent

[00:03:14] Slow flyer but there is nothing so not not so no it takes a lot of speed but it also so when i took off and i had all the the control surfaces even zeroed zeroed right when i took off you had to completely or you had to hold aileron almost full right there in order to make it fly without rolling left and it was just climbing like crazy i almost had to do full elevator down to keep it

[00:03:44] From from climbing how to do when you pull the throttle back once i went down to about a quarter throttle or a little below it kind of evened itself out but the problem became i was going a little bit too slow and i stalled it oops and luckily i was high enough to where i i had time to recover but when it stalled it just went into a spin and did not want to come out there so yeah it was a it was a hairy situation it was probably one of the worst maidens i have ever done on an airplane

[00:04:18] Well it's still in one piece it is oh yeah i was able to it took a lot of like i said a lot of a lot of trim but i think i want to go in and just re-zero everything again make sure the the throws are right and make sure everything's set up to how it's supposed to be set up from the factory apparently it had been flown before so it yeah i don't know it was a little bit hairy but the guy got it from before actually he had never flown it he bought it from a swap meet -huh yeah

[00:04:50] He tried to get it bound up to his transmitter and and let's just say he had an accident with it with the throttle and all that he to use a one ese or two two two okay yeah two but anyway so when he was was getting it ready and and doing his checks to make sure everything worked right he let's just say flew it into his leg

[00:05:21] He yeah apparently he cut his pants and hurt himself a little bit we laugh but it's really not funny just be careful yeah working with these things they're while they are toys they're dangerous toys so yeah yeah so he wanted to get rid of it because sure scared him bad juju so that's all the better for me right but it did not fly all that great so maybe it is haunted who knows but now we'll get it we'll get it taken care of check the cg and we'll check the

[00:05:52] Lateral balance as well yeah see if it balances cg was fine i mean i did check that

[00:05:58] Before i flew it where'd you do you find the manual get the cg out of the manual okay yeah it tells where it's supposed to be on that plane i checked it and it was okay only thing he said too is so when he did that he broke the the nacelle that was on it right and i don't think he realized when when he also did that he unglued it from the wing so when i first got it together and i was doing my test here at home before i was gonna fly it something just was off it didn't sound

[00:06:30] Right it didn't feel right it just it was off a little bit so i took it apart and i did find that that had come unglued yeah that's not good yeah got that all glued back together and then i still need to get a nose comb for it because apparently he said he he knelt on it when he was getting up and okay and crack that but now hopefully it'll be a good airplane here after we do some more that's a good looking airplane yeah i i like the looks of it but i'd rather be able to fly it and enjoy it more yeah we'll figure it out yep shouldn't take much no i don't think it will

[00:07:03] But other than that i haven't had much time since last episode to do anything so yeah cool so we're

[00:07:11] Talking about transmitters today yeah let's get into it yeah so we'll start with what we've got in front of us here we have a dx8 which is ron's transmitter i also fly with a dx8 a bit old school these days but when they first came out they were the bee's knees if i can say that they're still good

[00:07:31] Transmitters yeah they do what they need to do well it does everything i want yeah the only thing

[00:07:36] About the dx8 that could potentially be a problem down the road is the number of channels right and we'll talk about that so setting up a transmitter i'll just dive right into it sure

[00:07:53] This is for everybody listening this might be what's what i'm looking for kind of boring if you're not if you're not too sure of what you're listening to but i think this is important to cover because it is while it is technical it's important to know how to set things up right and how to well what you're looking for when you're trying to buy something even right it's good to know what the transmitters will do and what you can expect out of them and i don't know about you but

[00:08:22] I've bought things before and they were more capable than than i was capable if that makes sense oh yeah for instance a transmitter these things have lots of settings that you can adjust and and customizations and menus and things like that and if you don't know what some of this stuff means it could be a bit overwhelming especially when you turn the thing on and you just want to go fly right so we thought it wouldn't be a bad idea to sort of just go over some of the basics and maybe talk about what each function does and maybe what sort of airplane would use that kind of function yeah

[00:08:57] And it's also good to know too because if if you have something that you want to do or need to do but don't know what that's called or where to find it this should hopefully help you figure out what settings you're looking for and where to start exactly so okay let's get into it

[00:09:12] And this is all going to be you so talk to me well i'll try i'll do my best and correct me if i get anything wrong so the predominantly today it's 2.4 gigahertz so the different types of transmitters they're all kind of the the modern ones are using that sort of technology which i believe comes from wireless not cell phones but like the wireless phones we used to use in our homes

[00:09:40] Yeah so it was the same frequency so the 2.4 gigahertz is what we used right so most modern

[00:09:46] Transmitters today are gonna are gonna be on 2.4 gigahertz yeah but for you i guess not necessarily

[00:09:53] Me because i remember it with the old rc car days we had some am transmitters apparently some fm transmitters also yep because i remember you have to pick your what you said am had six bands i think yeah 27 band had six available frequencies arranged by color right so you had to be sure you did not have anybody else on your frequency or else you lost control of your car which that was before i was in the airplanes right cars were bad enough so i can't imagine like how many on fm like 75 megahertz

[00:10:23] Or 72 i think it was around 40 i think we had 40 available frequencies for air use on 75 or 72

[00:10:32] Whatever megahertz that was and so like i said if you had somebody else with a transmitter on your color for cars you had no control of your car i shouldn't say that you had just as much as the other person did right was that the same for airlines then yeah pretty much that's scary mixing of the streams yep yeah so that i guess i'm glad that we have advanced past i guess that technology

[00:10:56] Oh yeah and i've gone with 2.4 gigahertz oh yeah that's so much better the radios if i understand

[00:11:03] It correctly actually transmit farther than the fm oh yeah the range is as much higher yeah and you don't have to worry about interference from other radios either that's not at all yeah that's amazing

[00:11:16] Where we are now well i shouldn't say not at all but it's it's so much better and we don't have the issues with stray signals affecting our airplanes and our airplanes kind of freaking out for a millisecond and then coming back to you when they get the signal again yeah those days are kind of over

[00:11:37] Thank goodness well i our our local flying field still has the board up that has the the i guess apparently when you're flying clips were still in there yeah so how did that work then when you

[00:11:49] Were flying on a certain number i guess so it was basically clothes pins with the number written on them and the number was the frequency that you were using and if you had the clip or if the clip was missing out of the board and you wanted to turn your transmitter on first you went to the board to make sure your frequency was available i.e if there was a clip in there with a number on it you grabbed that clip stick it to your transmitter antenna and that was your way of letting everybody know that you were on channel 86 or whatever channel it was wow yeah so you didn't turn your

[00:12:21] Transmitter on in the in the pit unless you check that board so much different these days people just turn their transmitters on all willy-nilly and don't even think about it right because it yeah it

[00:12:32] Does not affect other airplanes unless they are bound to the that receiver exactly so yeah amazing technology i'm i'm glad it's that way now yeah i am too especially coming from the old am days when

[00:12:42] Yeah we weren't we'll talk about that so yeah when you when you first fire up in our example of dx8 and setting up a new model the first thing it's going to ask you the dx8 anyway it's going to ask you what type of model model type so the dx8 for those who don't know can do airplanes and helicopters and then once you've selected the model type in this case we're going to go with airplanes because that's what we're talking about then you'll have to set up the wing type so in the

[00:13:14] Dx8 and other transmitters probably very similar i think most of the spectrum stuff sort of uses the same menu layout flow yeah menu layout thank you so wing type what they're talking about is are you using one servo to drive both ailerons or is it a is it a biplane where you're using maybe two servos to drive four ailerons or or maybe an airplane where you've got one servo for each aileron you can select that in the dx8 menu and that will assign those servos a channel

[00:13:49] On the receiver so that's what kind of what i was alluding to earlier when i said with some of today's bigger airplanes the dx8 you're going to run out of channels especially if you're using multiple servos and not wiring up with a y-harness now a y-harness is basically a way to plug two servos into one channel they operate exactly like exactly the same as the other so if one moves 20 left the other one moves 20 left with that y-harness so you have no

[00:14:23] Independent control of those two servos when they're plugged in that way it takes an extra channel and programming to do that so that's what i was kind of getting to if you got a big biplane let's say and you want to put a servo on each aileron well there's four channels right there and then let's say you want to put a servo in each elevator and you don't want to do it through a y-harness where there's two more channels now we're up to six channels and we've only got two left and we got throttle and rudder still to do and then if we want to do anything cool like lights like we can

[00:14:58] Turn on and off or smoke don't kill switch yeah the gas what i'm saying so it's important to try to select a radio that you're not going to outgrow within the next few years because these things aren't cheap all right yeah what i mean so and once you've selected your wing type then in the dx8 the next thing that'll pop up is the tail type and that's sort of the same idea as the wing type because you can have lots of different types of tails you can have a v-tail you can have

[00:15:29] Dual rudders with with one elevator you can have dual rudders with dual elevators you could do a v-tail and then mix the v-tail with elevator i mean there's just lots of different types of tails and the modern transmitter will accommodate that and it will assign the channels for you that makes the most sense so that you can set your servos up and control them independently okay and they the dx8 is awesome it gives you a cool little handy dandy diagram of what what it looks like so if your airplane

[00:16:05] Looks like this and then you select this particular menu and then plug everything in just the way the dx8 tells you which is pretty cool so servo setup so that's kind of next something i want to say about servo setup though you should always try to set everything up mechanically the way you want it when you can and what i mean by that is don't use and i'll talk about this later don't use endpoint

[00:16:35] Adjustments to set the travel limits of your servo because this the servo for whatever reason could get a stray signal when you're sitting in the pits and you turn i mean and it would go past that mechanical limit you've set and it may bind or strip gears or or whatever so you want to try to set the mechanical limits i'm sorry you want to try to set the limits when you can mechanically that's why the servo horns have all those holes in them and the servo arms same thing they have all those

[00:17:10] Different holes in them so what that allows you to do is it allows you to set up the servo mechanically so that you don't overstress it and that should be done when you build the airplane set everything up 100 on the transmitter and then set it up so that at maximum throw i.e maximum travel on the servo it doesn't bind anything and if you let's say you need less travel well that's in hole or two holes at the servo horn or out holes at the control horn at the control surface

[00:17:47] If you can picture that yeah what i mean yeah that makes sense set it up right yeah when you're when you're building the airplane and then using the transmitter for fine adjustments exactly

[00:17:57] Yeah yep that's exactly right and then also kind of tying into that i'll talk just a little bit about mechanical advantage so the servo has the most amount of torque closest to the output shaft and what that means is if you have your push rod set up on the innermost hole at the servo that is going to have more torque than the outermost hole at the servo and it has to do with moment and arm and and i'm

[00:18:29] Not going to get into the the physics of it and leverage right so if you can and this is how i set my airplanes up to and i'm not a professional pilot or anything like that but and i've i've seen some 3d pilots set their airplanes up this way as well is they'll try to they'll try to get the maximum travel they want on the innermost hole that they can at the servo because that's where the servo provides the most amount of torque if that makes sense yeah i get it so mechanical advantage that's

[00:19:02] What that means so when you see that in the sometimes you'll actually see that in the owner's manuals for the transmitters that's what they're talking about mechanical advantage and then mechanical limits so that you don't over over stress the servo because you've gone past the mechanical limit of the servo if that makes sense yeah you don't want to break one by by putting

[00:19:27] Too much force on it exactly yeah surface gear or anything like that yeah so then i talked

[00:19:33] About endpoint adjustments and things like that and these are abbreviated lots of different ways i think futaba i think they call it atv adjustable travel volume but on the spectrums we they just call it servo travel which is actually pretty good because that's exactly what you're adjusting you're adjusting the amount that the servo travels at maximum throw so for some reason let's say you can't set up the mechanical limits the way you want to and you need less throw like you can't

[00:20:06] Move them in anymore at the servo the horn or the push rods you can do that electronically through this servo travel function and obviously more is more travel and less is less travel on the on the menu so that's one way you can set that up if you can't do it mechanically and and like i said other brands they they call it something else but it's it's end point adjustments i think the epa that was another one that i don't know aertronics might use that one but i've seen that one too

[00:20:40] But that's what they're talking about is the amount of that the servo actually travels from center to maximum deflection and then sub trim so we'll talk a little bit about trim so the modern transmitter now we used to have slides actually on the transmitter for each function yeah well now there are these cool little momentary on switches which are pretty cool and and that i should say

[00:21:10] This about trim also when you when you get your model flying the way you want it to you should always try to when you bring the model back if it has taken some trim let's say it's taken some right aileron trim to make it fly straight and level in the case of your new airplane it took a lot of trim to make it fly straight right it flies straight and level when you bring the airplane back you should try to mechanically move that push rod such that you can recenter your trim and the reason

[00:21:46] I say that is because it's always easy to remember to zero your trims than to try to remember oh well i think i had five degrees of up elevator for this airplane if at the end of the flight you zero the trim and make sure the elevator is still at that position at zero trim you'll always be right at zero trim yeah sort of makes sense yeah and that's a habit that i got into a long time ago

[00:22:11] Especially after a maiden because not very often have i had an airplane fly hands off right off the

[00:22:19] Building table i mean it happens but usually there's at least some trim so after the maiden flight i get it all trimmed out so it flies straight and level and i land i'll once i've landed i'll turn either leave leave everything on or i'll turn everything back on and i'll actually measure the deflection at neutral stick for each control surface and then what i'll do is i'll zero the trim and then i'll mechanically move either the clevises or whatever to get back to that whatever that measurement was

[00:22:51] At zero trim that way i know at zero trim the airplane should be flying yeah because it's

[00:22:58] Always best to have an airplane fly or set up to fly at zero trim so change what you can on the airframe itself as opposed to in the radio exactly and yeah that makes sense yeah it makes a lot of

[00:23:09] Sense and if you make a habit out of doing that early then it's just something you kind of like a pre-flight you just sort of do without even thinking about it well not only that but if you do go

[00:23:20] To sell it or if you change radios or something along those lines you're going to have an easier time setting it up it could be that the person that flew this one last when i or flew it last before i had it could have had some really really odd trim settings in their radio and that's why it was so off for me even though everything was centered yeah because you centered everything mechanically

[00:23:45] Such that you thought it would fly straight and level with everything well it had the servos and

[00:23:48] Everything in it still so i didn't have to add any of that stuff so it would have been set up badly from them yeah so when i'm thinking it's going to be flying okay it was just set up that far off that the radio had to make up for it so right yeah i can understand going back and and resetting that up

[00:24:03] The right way yeah so i said sub trim after we were talking about travel and sub trim is a handy thing to use if for instance there are some airplanes out there well there are lots of airplanes out there that that behave this way some for some reason one turn or even a half a turn on the clevis is too much in either one direction or the other i.e you went out and you maidened and you brought back and you measured it and i need five degrees above elevator to fly straight and level at

[00:24:37] About half throttle well at half throttle you you can only get like four and a half degrees and then if you move the clevis another half turn now it's five and a half degrees i can't get that sweet spot that's what sub trims are for sub trims are not for getting more trim when you've run out of trim on the transmitter i've seen so many people they they run that aileron trim all the way to the right and it's they won't go any farther okay i'm gonna get in my sub trim and you're gonna get a little more yeah it works but that really is not a good way because now it's not it's not best practices

[00:25:09] No and when you're talking about a trim right and when you're talking sub trim too you're talking about the menu sub trim yeah yeah i'm not actually the the click buttons that are on the transmitter

[00:25:19] Exactly right yeah yeah so and usually sub trim is a is a very small percent of your overall available trim on the trim switch on the front of the transmitter so what i'm saying is like

[00:25:31] Let's say your aileron trim from zero gives you another if you go full right trim let's say it gives another five degrees of travel sub trim might give you a half a degree if that sure puts it in perspective yeah and the sub trim is an electronic thing it's like you said it's not a switch out here on the outside of the face of the transmitter yeah it's not something you would

[00:25:52] You would adjust while flying not usually you shouldn't unless you have really really good

[00:25:57] Confidence in your airframe airplane yeah so that's sub trim and then the next thing reverse i mean that's kind of self-explanatory it basically just allows you to reverse the direction of the servo so for instance if you pull back on the stick and it gives you down elevator well you can flip the switch or get in that menu and flip the reverse on the elevator and it'll make it go the other direction i have the benefit of remembering when we used to have to buy reverse rotation servos because

[00:26:29] There was no such thing as throttle reversing on your transmitter or or setting the servo up so that the control horn was on the other side if you had room to do that or buying a reversing there's a little thing you could plug in line with your servo that would actually electronically

[00:26:50] Flip them out or whatever wow yeah that is old school yeah so that's reversing

[00:26:57] And then speed on the dx8 you can adjust the speed of each channel which is kind of cool especially if you've got like landing gear is what i like to use it for here is a great example you can slow it down to make it look more scale the last time i used this function was on a b25 that i had put together for a friend and i put it on the flaps so the flaps came down kind of slow which was really really actually really helpful in flight because it gave me time to adjust

[00:27:27] The back pressure on the stick or what have you and they just look cool yeah so more scale more realistic looking right right so so those are are some of the more basic functions that you'll get into and then beyond that we'll talk about dual rate and exponential dual rate is a is a switch on the front face of the transmitter that you can flip and on the dx8 we can select our switches which is pretty sweet we can put our dual rate on any of these switches

[00:28:02] We want to it's assignable and i think most modern transmitters are probably that way also so on my dx8 i have let's say my elevator dual rate is over here on the one labeled elevator dual rate and it's a three position switch so i can actually have three options if you will so and what dual rate is is it limits the amount of travel depending on how you have it set up and and how you have your switch set up so for example an airplane that well 3d pilots i think sort of use this sort of

[00:28:35] Technology at high angle or high alpha flight when they're doing their crazy tricks and stuff they'll have maximum rates like as much deflection as they can get and then when they want to fly around more precision type aerobatics they'll go up here and they'll flip their dual rays which would slip let's say it limits the travel of all those the elevator and ailerons to 50 so the airplane flies smoother at the same amount of stick travel so that's what we're talking about with with dual rate and how you can assign it to switches there's lots of other ways to to go about that also i know some pilots

[00:29:12] Will take and they will assign all of their dual rates elevator aileron rudder all of them to one switch and they'll call it a flight mode switch so sometimes you'll see that out there flight mode and that's another way you can you can customize that switch to make the airplane fly the way you want it to different styles of flying so exponential that's a tough one that's what i just wrote down to make sure that we're going to talk about actually yeah so what i use exponential for is i call it

[00:29:47] Soft center it deadens the center of the stick it can't yeah right or it can it can make it the opposite

[00:29:54] Too if you don't have it set up the other way the wrong or the right way right but the point is to

[00:29:59] Right deaden the center of the sticks right so another good example would be the 3d type of flying maybe maybe maybe you're really maybe you were brought into the hobby the good way and you were taught to fly with with by pinching the sticks i can't fly that way that's not the way i learned i'm a thumbs guy i stick my thumbs right on top of the sticks just like this and that's not very precision right so for a guy like me i like to get in there and i like to mess with the expo

[00:30:32] Exponential and what i and what exponential does if you're not familiar is it will change the way the control surface behaves with the movement of the stick so for instance exponential just like the term exponential implies the farther you move the stick the more throw you get and the the rate of throw exponentially increases or decreases if you don't want to follow convention and what that does is it makes the airplane less sensitive around the center which is great for a guy like me who flies

[00:31:07] With his thumbs because as i get older i'm not as smooth as i used to be so exponential with

[00:31:14] The thing that's nice about that is as you move your stick when it's in the center you move your stick more in order to move your control surfaces less and then as your stick gets to the outer limits of how far you can physically move the sticks on the transmitter your elevator your rudder whichever ailerons whatever you have set up for will move more does that make sense am i explaining that okay it does so the first 75 that you can move your sticks might only move the control surfaces 25

[00:31:51] Exactly but that last 25 that you move the sticks will give you the last 75 will give you the last 75 correct of throw on the control surfaces no that's a beautiful way of describing it yeah i hope that

[00:32:02] Makes sense and it does and and what it does is it it softens the the control response around the center so you can be a little bit more precise if you want to especially if you're like me and you fly with your thumbs yeah but yeah that's that's a great way to describe it the the farther you move the stick the more exponentially the throw increases yeah and so if you move it in a at the same speed

[00:32:29] All the way across right you will notice that the control surfaces do not move in a linear fashion exactly they will move slowly at first and then move fast to get to the very end and i'm glad you said

[00:32:41] Linear because that takes me to the next point which which is curves ah so if you thought yeah if you thought exponential was difficult to explain and i'll do my best to explain through curves so the dxa we can we can put all of our channels on and and program curves in there and it's a lot like exponential but it's completely customizable whereas exponential is usually done as a percentage so that at 50 throw you're only at 20 actual throw on the airplane so like

[00:33:19] 50 stick is 20 throw and then 100 stick is maybe 80 throw however you whatever percentage you've assigned it to in the exponential menu in the curve menu you can make those numbers whatever you want like you can have a u-shaped curve you can have a a linear curve which would be a line

[00:33:43] For those that are listening or you could have if we haven't lost everybody yet right or you could

[00:33:49] Have a kind i mean there's bell it's completely customizable and without without trying to really dive into it it it it's it's basically once you're so comfortable with a particular airplane usually by the the time you get into the curves you're flying that airplane a lot and maybe even in competitions and you have a curve set up for a specific function for example i know with pattern

[00:34:25] There's a box that you have to do certain maneuvers in within these boundaries and a curve what it would allow you to do is allow you to fly your entry and exit out of the box or the prayer or the boundary that you're allowed to do the trick with a smooth kind of flying like normal or whatever but then you have these curves set up so that when you reach maximum throw on the stick it's either completely crazy like maximum maximum throw on the airplane or if it's just a

[00:35:01] Simple roll you may flip the switch turn the curves on and maximum throw on the stick may only be 10 throw on the actual control surface so it's it's a way of of customizing the the way the airplane flies was just a flip of a switch and just like i failed to mention that just like exponential or dual rates rather all of these functions can be turned on and off in flight with the switches depending on how you have them assigned so yeah mid-flight if you're you're out there doing crazy 3d stuff

[00:35:38] And then you're like i'm tired of this i just want to go fly smooth again you flip a switch and anything it turns on all your curves and your exponentials and now you've got this nice smooth flying airplane that you don't have all those maximum throws anymore which is easier to land

[00:35:53] Which is easier to actually fly with exactly because you don't have necessarily have the

[00:35:58] Throws that you had before that's exactly right okay yeah i'm not talented enough of a pilot to take full advantage of that i don't fly often enough yeah and i always say i'm i'm going to but for whatever reason it never works out but i would like to get to a point someday when i fly that i would actually be using these switches for for all the things that you can use them for of course

[00:36:26] Sticks don't really need all that technology not at all and the next thing

[00:36:34] Differential that just simply means you can adjust with our spectrum dx8 any of the channels you can make them operate more in one direction than the next that's all that means so sometimes i know way back when we we used to have to do this with these really really big wheels essentially that were on top of the servo and we would mount the push rods off center

[00:37:06] So for instance if you could picture a wheel in front of you and then there's a a crosshair in the center instead of mounting their the pivot points for your push rods right along those lines you'd move them up and you would get differential throw that way so some of the old trainers we used to fly we used to use differential throw on the ailerons because you would have things like adverse yaw or other weird things going on because when the elevator dips down into the airstream it causes

[00:37:39] More drag than it does when it moves up into the airstream and that drag causes a yaw well you don't want the left wing dragging behind when you're trying to make a right hand turn it sets up crazy aerodynamic weirdness so with differential we corrected that by making it so that the aileron that was going down say on a let's say our right aileron was going to go down and we're going to make a left hand turn we would make it so that the right aileron would go up more

[00:38:11] Than the right one went down and that's differential throw and that's really all we're trying to correct is

[00:38:17] Weird aerodynamic weirdness and that would be better to set up then on the radio than it would

[00:38:23] Be physically on the plane it's much easier to set it up in the radio because now i mean and there was a lot of math involved and i remember this airplane as a kid that i put together they actually in the building manual for the airplane they gave you a diagram on how to drill the holes on the servo horn so you'd get the proper differential throw on the ailerons yeah we don't have to do that

[00:38:49] Anymore we can do it all electronically okay so that is one plus to the new new computer radios

[00:38:56] Any pluses yeah yeah so yeah that was differential throw and then the last the last real well the two topics i guess flap system so if you have that enabled on your transmitter that just simply means you can use your ailerons as flaps we call those flap rons or you can have individual flaps and ailerons on your wing and that's all assignable in the transmitter so long as you have

[00:39:28] Enough channels to to plug those servos in and that's part of the wing setup when you're first setting

[00:39:33] Up your model yeah it is but it falls after like in the menu for some reason it doesn't they don't put that in the dx8 to get the flap system operational you have to select back in the original menu in the wing type that you have that sort of wing right otherwise it won't open up that option for you right so and then the last thing is mixing we can mix any channel with any channel on today's radios

[00:40:03] Which is pretty wild yeah so if you i mean you can change elevator based on what your throttle position is yep so if your throttle is high and you need more down elevator on that to keep

[00:40:15] It flying level you can do that all electronically mix it in electronically yep or if you have if you for instance if you have an airplane that that you like to fly knife edge but at neutral like let's say you have full right rudder input and neutral everything else maybe the airplane wants to tuck to the gear but that means it wants to like turn towards the gear you can yeah you can mix a little bit of like the more rudder you feed in you can mix in down elevator to prevent that so yeah that's

[00:40:48] What mixing is just mixing any channel with any other channel which is pretty useful when you're when you're trying to tune out sometimes bad tendencies of airplanes yeah what about what about the

[00:41:01] Different channels so what would you use obviously a basic is going to be a four channel right what would you use the extra channels for to get up to eight or past eight even to 10 12 whatever

[00:41:13] Some of the the higher yeah higher channel ratings well i mean anything you can plug in to a port of your receiver could potentially be something that you would control with your transmitter

[00:41:29] I use the example of using a y harness to to run two aileron servos if you wanted to run those ailerons well you have to run those ailerons separately if you want to use them as flaps also flaperons so that is an additional channel so now we're at four channels plus one more because we have to have that open channel to plug in that extra aileron servo if you're using separate servos let's say on an elevator you've got two elevator halves maybe you want to maybe you want to mix

[00:42:02] In a little bit of differential elevator throw when you're when you're to increase your roll rate if you're going to be doing some crazy cubanates or or rolling circles or whatever well there's another port you need so now we're up to six channels but traditionally we used to think of channels as as functions so a basic four channel is throttle rudder aileron elevator some fun things you can do you could set up flaps just as flaps by themselves you could set up retractable

[00:42:37] Gear now we're up to six channels you could put maybe a bomb drop there's seven channels maybe you could rig up some electric lights or something like that landing lights if you want to turn something like that well there we're at eight channels and we haven't even begun to split channels or split servos so you can run out of channels pretty quickly is kind of what i'm

[00:43:01] Getting at yeah but yeah optical kill switch for a gasoline ignition exactly what else can you do a smoke system smoke system you have a big enough plant yeah there's a bunch of other things that that you can that you can use channels for so it's really if you're going to go buy one it's best to get

[00:43:20] Back in the day we used to use remote needle valves i've never even heard of that oh yeah yeah back in the day we we used to so before there were electric ducted fans there were ducted fans and they were nitro engine housed in the fuselage and turning a big fan inside a big housing

[00:43:47] And they were usually well a fan develops its thrust by turning it really really fast so these engines were usually very highly tuned crazy crazy rpm with tune pipes and just screamers and it was not uncommon for these things to once you had them tuned on the ground they would unload once they got in the air and the tune would be off so we'd have to we'd find ourselves tuning them a little bit lean on the ground so that when they unloaded in the air they would richen up or vice versa it's been

[00:44:23] Such a long time i don't remember but yeah so we had this cool little gizmo on the on the needle valve of the of the motor that the entire housing that the needle valve was in had an arm on it and we had it hooked up to a servo so we could fine tune the the mixture in the air wow and that was another

[00:44:43] Channel hmm yeah amazing how things have changed really how things have gotten better oh what i was going to say crazy is when you're going to purchase a transmitter get what you can afford yeah absolutely think about what you're going to want to do and then probably add a couple because you're going to forget channels for sure you're not going to think necessarily about what you're going to do five years down the road because these are expensive i mean i think i want to say that was 450 bucks

[00:45:15] 400 bucks maybe something like that when i bought it and it could be it's been it's been several years since i bought it and i know new ones are the same price and they go up a lot more from there even

[00:45:25] Right i remember when the dx 18 came out i just when it came out i i was like holy cow 18 channels i would never run out of channels well i mean guys with these big airplanes and especially the scale the big scale airplane warbird guys that are doing competitions and stuff oh yeah 18 channels

[00:45:48] Is nothing yeah yeah it's amazing how quickly you can fill them up yep but yeah definitely definitely

[00:45:54] Good advice buy what you can afford because you don't want to have to buy it again later because you're ran out of channels or functions or what have you yeah yeah so anything else you want to cover no i mean i think i think i've covered all the all the stuff that i feel confident talking about i mean these transmitters today they're so capable yeah and we haven't even talked about helicopters

[00:46:26] Which we're not going to we're not going to i have not qualified i don't have a helicopter i don't want a helicopter the helicopters are cool that's fine but i like them yeah i have had them

[00:46:37] Off and on over the years and i can fly them yeah i can fly them basic i can't do any of the cool tricks and stuff that they can do now but yeah you want to talk about some complicated setups sometimes oh yeah oh i was gonna say with the so because i'm old and i've been in the hobby a long time i've seen some crazy workarounds so we're talking about flapperons so nowadays you

[00:47:08] Know you just oh i want flapperons i'll just put a servo in each wing panel drive them on separate channels mix it in my transmitter i'm good to go well it used to be in fact there was a company man i can't remember the name of it but they made a tray you had to cut a big piece or design a big piece in the center section of the wing to house this tray and what it was it was a tray that slid on two rails and you put a servo right in the middle of it and it would be your aileron servo right so it'd be a standard aileron setup with one servo but the tray would move back and forth and

[00:47:44] The tray was driven by another servo so that's how you mixed your flapperons so as the tray would move

[00:47:51] Back and forth it would change whether yeah they would go up or down together but then as the aileron

[00:47:57] Servo rotated within the tray then that's how you got your aileron function mechanical engineering over

[00:48:03] Computer engineering that's amazing yeah i used to own one of those that just seems like it would go wrong so easily it would get bound up it would get it worked really really well really yeah it

[00:48:16] Really did it was trying to think of the airplane that that was on it was a big high wing thing not not a stick and it wasn't it wasn't a trainer but yeah that's that's how we that's how we did flapperons back then that's perhaps some of our listeners will remember that if we and make me

[00:48:36] Not be the only old guy if we have any listeners left at this point right this was this was kind of in depth it was a tough one i understand yeah but we got through it hopefully it was enough to describe some things for people that didn't know what they were talking about there was some stuff in there i didn't quite understand i've not used any of the curves i use exponential but i've never used any curves i don't think i probably would but it's good to know kind of what it would be used for so yeah i mean it was an interesting discussion but very factual right so i was gonna

[00:49:13] Say something but wasn't that important i guess okay totally slipped my mind it happens when you get older well anything else no that's i think oh what i wanted to say was if anybody if i've confused anybody out there or if i've gotten it wrong feel free to hit us up text us at the at the number there that we gave you at the beginning of the program send us an email and we'll i'll try to correct it or whatever on the on the on the show well if tom was wrong and what he said

[00:49:46] Be sure to email him direct leave me alone because that was not what i was saying that's tom at rc plainlab.com and if you just want to tell me that i was doing good and listened to a lot of stuff today my email address is ron at rc plainlab.com but yeah you could also email

[00:50:02] Ron and tell him everything i got wrong i'm sure he would love to hear that that's true i guess i'll

[00:50:07] Read it before i forward it on and make fun of you a little bit for it but that's all i got all right me too until next time i'm ron i'm tom thank you for listening yep see you later we hope you enjoyed

[00:50:17] This episode of the rc plainlab podcast for topic suggestions to ask questions or to give any feedback connect with us at rc plainlab.com or email us direct at either ron at rc plainlab.com or tom at rc plainlab.com you can also text us or leave us a voicemail at 818-351-9846 please subscribe rate and review us on your favorite podcast app until next time may your landings be gentle