Ep 40: Scratch Building, Listener Questions, and What Makes an Airplane Big?

[00:00:09] Hello and 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, welcome to the RC Plane Lab podcast. I’m Ron and I’m Tom. Can you believe, Tom, by the way, that this is episode number 40? 40, 40, Yeah, yeah, I just noticed that when I was starting the file- 40 episodes- we have sat down and done this 40 times. 40, Well, 30, no, because, yeah, the wives did it once. Well, that’s true. However, we’ve messed up and had to redo a.

[00:01:04] Couple, I was gonna say: are you counting the ones that we started over from scratch? I’m not.

[00:01:09] Reporting, a full one. That was only once or twice, though I think twice, twice, and that was computer glitches. Yeah, if I remember it wasn’t because we stunk or anything. We’ve never done that. What are you?

[00:01:19] Talking about. We’re always intriguing and engaging and full of it interesting. Oh, we’re definitely full of it, but anyway, welcome to the 40th episode. Thank you. 40 Times we’ve- yeah, that’s feels like 100. I don’t know how to take that. I’m teasing, wow, I’m teasing. No, it’s hard to believe it is. I can’t believe that we’re still going. Honestly, I mean, no, you’re right what I’m saying.

[00:01:48] I’m glad we are, though I am too. It’s fun. It’s been fun, which reminds me, speaking of: are we still going go over to our website, fill out the listener survey to give us some more show ideas? Yep, that’s what we need. Yeah, we need more things to talk about. Yep, because we’re terrible at thinking.

[00:02:04] About it on our own. We really are, but it always seems to come together. It does. I hope, I hope it.

[00:02:08] Seems like it does. I mean to us it does, but I don’t know about to the people listening. Well, I mean.

[00:02:13] They’re listening numbers, so prove themselves right, I guess. So, speaking of numbers, I just wanted to remind everybody that if you like what, what we’re doing, and if it’s helped you out in any way and you want to, you feel like maybe you’d like to help us out. Go out there and become a patron. Get out there on patreon and show us some love. Yeah, also, I’ll just a reminder: we spoke last episode about that cool aerodynamics article that one of

[00:02:44] Our listeners sent us. I went ahead and put that link out there on the forum so you guys can read.

[00:02:47] That it’s really good stuff and you finally did it. I did, you went over there and you posted.

[00:02:52] Something like: and you only had to remind me what twice, three times, I don’t go do it. I, I’ll be honest, I forgot about it for a couple minutes too, yeah, but that’s okay. But it’s on there now. You, just if you want to search aerodynamics, it’ll, it’ll pop right up and that link is there and it’s.

[00:03:08] It’s good stuff. Yeah, it’s a very interesting article, so I agree, good, good read. Let’s move on. Let’s move on. What’d you get done on the dualist? No, that’s not what I want to bring up, nothing, I’m sorry, like I really I’ve been doing other things and had not had a chance this week to touch anything on it, and I feel bad saying that because I feel like I’ve like, I’ve given up. I mean like

[00:03:34] I feel you, but I’ve got your back this week. Good, I got a lot done on my dualist awesome. So, yeah, what did you do? I have a nearly complete wing. I got the ailerons cut and the trailing edge stock cut and glued on. All the shading, of course, is done. I got the leading edge sanded to shape. I got my wingtip blocks assembled ready for shaping. The only thing, sorry, how?

[00:04:01] Did you assemble those? Because I still don’t know if I want to do that or not, but

[00:04:04] So I had to laminate a couple of blocks together to get the thickness I needed. Okay, and that’s where I’m at. I just needed I just need to cut those to a rough airfoil shape, stick them on the end of.

[00:04:16] The wing, and then I can final sand them. So you just glued a couple sheets together. Blocks, yes, blocks, okay, but I don’t feel like you’re that far ahead of me then on that part. Well, and you still have.

[00:04:27] More, more work done, I feel like, because I still don’t have any nacelles. Well, that I’m dragging.

[00:04:34] My feet on that too, to keep you behind me, I think, because I do kind of feel like this is a race at this point. So yeah, your fate is in my hands because I have a. I have also a nearly complete.

[00:04:48] Tail horizontal stab is done. Oh, that’s not fair. And the vertical, of course. They’re just quarter inch sheet for the vertical. But that’s all cut and I just need to final sand it to.

[00:04:58] The final shape really, yep, wow, so did you? You stuck with the shape on the on the plans I did. Yeah, I was gonna look seven. I know well, that’s what I like. Okay, you’re right, I guess I shouldn’t.

[00:05:10] Say it that way, I was gonna modify it. I was gonna. If anyone is familiar with a, a mooney, which is a civilian, I don’t know because I’ve never heard of it- airplane, okay, but they have a kind of a unique shaped vertical stabilizer. It actually almost looks like it’s forward swept and the and the stab is that way too a little bit really neat looking. I thought maybe I would kind of go that route with the tail on this on the duels, but in the end I decided I wanted to go for the classic vintage 70s. Look. So that’s what I did. Well, that’s good, because you’re

[00:05:44] Following the plans, right, so you don’t want to deviate too much. Yeah, if you want to see what a

[00:05:48] Mooney looks like. Just type in mooney, m-o-o-n-e-y 201- 201. That’s what I’m working on. Let’s look it up really quick and you can talk about something else. But at, yeah, I’ve got. The tail is complete. I’m gonna, now that I have the fuselage formers, I’m gonna go ahead and start getting the adjusted adjuster jig cleaned up. So I have found the picture. It looks like they cut.

[00:06:11] The back end of the airplane off and put it on backwards. Yeah, kind of okay. Yeah, it was very.

[00:06:16] Unique to that is. That is odd, but I like them. I’ve actually flown one of those. So back in the day, flown in or flown one flown. Oh really, well, we’ve. I think I may have mentioned it in prior episodes, but I- I have a private pilot license. Haven’t flown in years and years and years, so I’m. It’d be like starting out of spec, but yeah, I have, I don’t know, 15 or 20 hours.

[00:06:41] Logged into mooney 201. Really, I did not know that. Yep, look at me learning stuff about you. I’m not interesting, so there’s nothing to learn about me. Oh, you’re interesting.

[00:06:52] So, but anyway, yeah, that’s where I’m at. The dualist is the wing, like I said, is minus the nacelles. Like the retractable landing gear is in the it’s mounted. I’ve got the plumbing ready to go in there, I’ve got the holes all drilled and the servo mounts are done. I mean, it’s, it’s, it’s really.

[00:07:11] I mean a lot of progress. Well, you’re probably way ahead of me then. Like in all honesty, I still

[00:07:16] Don’t have a fuselage started. You have a fuselage started that and you have nacelles. That was a

[00:07:20] Quick, easy fuselage start. Yeah, but you have nacelles too, that’s true. I just haven’t glued them on yet. Well, they’re complete at least. True, I’m, I’m looking forward to being done with that. I mean, like not in that way as much, as just I want to see it finished. I mean, I really.

[00:07:35] Wanted my wing to be complete like engines, gear, everything in the wing, before I moved on to

[00:07:42] Anything else, but yeah, that’s my fault, like that really is my fault to get other stuff.

[00:07:47] Done so well? Not really, because the nacelles were away. I was waiting to figure out what I was going to do with the doublers on the inside. The plans call for 16th inch plywood, which.

[00:07:56] Apparently, is really hard to come by, difficult to find. Yeah, I don’t understand that, but so are that. I noticed you brought something over, yeah, so I think I’m going to make the doublers out of.

[00:08:05] This stuff right here. It’s a 16th inch base wood. Why are you making fun of my wife? Because I knew I would get a chuckle out of you. No, it’s bass wood. So I figure, poor crystal it’s not. It’s not a laminated wood really, but it is hard. So I figure, if I can maybe have you etch at least the outline of the doublers on these, then I can cut them. And if the laser won’t cut them, I’m saying no, I think the

[00:08:33] Laser will cut that. That’s pretty thin, okay, like it’ll do 16th inch ply, no problem. Oh well, that’ll cut this then, yeah. So I know you’re going up to the, the hobby shop this weekend, though are you wanting to try and find that there? Do you want me to hold off? Yeah, let’s hold off, okay, because if I

[00:08:47] Can, if I can find, I would rather use plywood. Okay, especially since I’m going nitro the vibration.

[00:08:53] And the durability issue, and the dirtiness and the dirtyness and the slimy.

[00:08:58] Oily goodness, the smelliness. I would rather go with a, with a plywood. So, okay, if I can’t find any, I’m gonna go ahead and leave these here. If I can’t find any, I’ll just give you the word and you can cut them at your leisure, okay, but anyway, yeah, that’s pretty good, pretty good progress on the doulas. I feel, I feel like, oh, that’s it, that’s it that? Oh, what do you mean? That’s it? Oh, I don’t know, I just thought you’d- I don’t know, have a complete tail. She did like the structure built and she did.

[00:09:29] And everything. Oh, I forgot you were doing that. Out of that was stick built. Yeah, okay, following the plan. That’s right, I’m, because, like I said, I think I’m gonna need some tail weight, so I’m gonna do my sheet, yeah, so, oh, cool. So, which reminds me I think I need you to buy me some three ace balsa.

[00:09:46] I don’t have a pen. I do have a pen. Hold on, go ahead and make a list while we talk to our

[00:09:53] To our listeners. If I don’t, I’m gonna forget. Yeah, okay, I do that too, so cool and that’s all that’s.

[00:10:00] All you’re gonna talk about on that then, huh, yeah. So I mean yeah. I mean, well, I have the, I have the fuselage formers and my goal for my next update is to have. You don’t have those. No, I do. I looked around and I have the, the doublers with the holes vertically. How did you get the? I don’t remember cutting those. You did because you handed them to me and I was looking, I was cleaning off the board getting ready to build my tail. I was like, oh well, I do have formers. Here they are. I don’t. Oh, these are, oh, these are the right ones. Are they really they are? Yeah, I don’t remember.

[00:10:31] Cutting them for you. Maybe they were an extra set that you cut, that you didn’t like, or something. I don’t.

[00:10:36] Know well, you check those out and make sure they’re right, because I don’t know you did.

[00:10:41] You did make some. I think you did make some updates. Yeah, the ones I thought I gave you.

[00:10:46] Were the horizontal holes. These have vertical holes. Oh okay, I’ll print. I’ll print the plan out. I know.

[00:10:52] Now, you did cut those, but then I had to leave you an air tank, because then we were going to redo the where I put the, where I put the pneumatic tank for the retracts. Okay, that’s just one, though.

[00:11:06] I mean, like I don’t have to redraw all of them, no, just re-cut all of them, we’ll figure it out, we.

[00:11:12] Will. If you have. No, that’s good news. I hope to have the adjuster jig cleaned up and ready to go and have at least a fuselage, sort of in the in the beginning stages kind of like where I am. Yeah, that’s my goal, and then I will feel like I am at least where you’re at. Well, that means I have.

[00:11:30] To do more, and if you’re gone this weekend, that gives me plenty of time. It does. That’s awesome. Yeah, stay gone for quite a while, that way I can get more done and pass you. Yeah, right got.

[00:11:41] It. I will. I will pause on my build so that you can get ahead. I appreciate that. I mean, you’ve kind of been paused for a long time. So I was, I had, I, I was, I was the slacker last week. I had no update, but I did have one, and what’s funny is at least on my dualist I spent all day, like today, all one day, all of one day on it. I did work a little bit on it saturday, but anyway, it just doesn’t. It’s like I spend hours on it and it doesn’t look like I spent hours on it. Yeah.

[00:12:18] Does that make sense? No, I get it because of all the fiddling that I have to do with mine, because of the retracts and the complexity of the build. Well, that’s why, like with mine, well it might.

[00:12:28] Not look like. I mean, like to you it looks like I’ve done a lot, yeah, but to me it doesn’t look like I’ve done a lot. But I also don’t take into consideration all the literally hours upon hours I have in designing and cutting the material, like cutting is not long, but actually tracing the plans.

[00:12:45] And getting in the- yeah, getting in the program and drawing apart, and then redrawing the part, and then realizing that’s not going to work. So you’re going to redraw it again. And well, my problem.

[00:12:54] Was following the plan actually, because now, knowing that things didn’t line up right, if I’d known that at the beginning- which I know now for next time, how to actually go through and make everything lined up right, and I won’t go through that again. But let me ask you this then: so do you consider this a scratch build or do you consider this a kit build, like? Can I count this as my first?

[00:13:20] Scratch build airplane. So I consider this neither of those. This is a plans build, we’re building, and

[00:13:27] I forgot about plans. Yeah, okay, yeah, well, still then, do you consider this a plans build or do you?

[00:13:33] Consider this a kit build. No, I consider it a plans build because we are still producing our own parts. Even though, even though a laser is cutting some of them, I still feel like we are producing our own parts. So, therefore, we are building an airplane from plans. See, I don’t know.

[00:13:53] About that. We’re not buying. We’re not buying the parts- okay, well pre-made. So are you and I building this differently, then maybe you’re doing a kit build and I’m doing the plans build. Then, since I’m the one doing all the computer work and the cutting- like the physical cutting with the laser- is done.

[00:14:16] By me. No, I still feel like it’s a plans build because I’m, okay, I’m, I’m finding a source to cut my parts for me, because that makes my life easier. But no, I still consider it a plans build because I’m, I’m, I didn’t buy a box of wood and an instruction manual to build this airplane. Okay, I can see that what I’m saying. I bought all the wood, right, yeah, so, and yeah, you’ve helped me cut most of the pieces. But no, I still consider it a plans build. Okay, so kit build to me is you get a box?

[00:14:54] With instructions, plans and all the stuff you’re going to need to build the airframe in one box, all cut for you, ready to go, or at least all the unique shapes are cut for you, or die cut and you open the box and you dump out the parts and you start assembling pieces. It’s not. That’s not what.

[00:15:12] We’re doing here. Okay, I can see that then- and then scratch building. I know we’ve talked about before, but I don’t remember. You don’t consider plans building and scratch building the same, so what are?

[00:15:24] Like: what’s a scratch build? So a scratch build is something. You’ve got an idea in your head of a cool airplane and you just build it. Oh, just like, just like that. So no plans, no plans, no anything. Anything associated with that airplane is completely designed by you.

[00:15:45] So does that mean completely designed by you, without plans, or do you consider that if you, if you make?

[00:15:52] The plans, you make your own plans and build off of those, then that’s, it’s still a scratch build, because you’re not starting with someone else’s plans. So, have you ever done a scratch build? Yes, yes, I have. Okay, what? So what have you built? Well, I mean a few foamies, which I don’t know if you, if you count.

[00:16:08] Those. But I don’t really count. I mean maybe I should. But right, it’s fine you’re doing.

[00:16:14] Foam, yeah, but no, I have, I have it. I have done one that stands out anyway. Scratch build that was entirely my own back in the 80s. Oh wait, what was? It was a firefox. What, like the.

[00:16:30] Internet browser? Seriously, you don’t know firefox? No, I don’t know what you’re talking about.

[00:16:36] Is that a plane? Oh, is it a movie? Tell me, are you serious? You’ve never seen the movie firefox. I’ve never heard of the movie firefox. Okay, so it was a clint eastwood movie. I mean, the fact that it was a clint eastwood movie and you haven’t seen it, okay, I can get over that, I guess. But it’s an airplane movie. I mean, it’s a movie about an airplane. You seriously, you’ve never. You never even heard.

[00:16:56] Of it. We’re from different generations, buddy, what are you talking about? All right, so this movie, when did it come out? Google says 1982. Okay, I was one, okay and like so. So the movie- I’m not gonna spoiler alert- the good guys win. I think the spoiler has kind of passed, I mean yeah.

[00:17:21] Anybody that’s gonna see it has seen it. The premise of the movie is: the russians are working on this really super, super agile and super techno airplane and it was called mig 31 is what it was called in the movie. Okay, yeah, and so the? The premise was that clint eastwood was like a retired air force general pilot guy got together with cia and mi6 from the uk and they conspired to steal this thing from the russians. And aside from the, the plot of the movie-

[00:17:58] Sounds like a great movie to begin with. It was actually okay. I mean it didn’t. I don’t think it did really well in the in the theaters, but anyway, the movie for me wasn’t really about what they were doing. For me it was about the airplane and it was this cool looking kind of delta wing canard. Canard is means it has an elevator in the front and not the back, and so I watched the movie, obviously, and I kind of laid out, drew the airplane on paper and then sort of scaled it.

[00:18:29] Up and now. Granted, I was 12 or 13 years old at the time. So for a 12 or 13, in my opinion, for a 12 or 13 year old to sit down and draw an airplane and then build a balsa model out of it at that age, I mean I think that’s pretty cool, that’s pretty. I don’t know too many 12, 13 year olds that would do.

[00:18:49] That sort of thing today. But that was back before they had like tv and stuff in the home, right? So you?

[00:18:54] Didn’t have much else to do. So, yeah, I, I drew up my own plans and I built this thing out of balsa and light ply. It was a ducted fan. It was a twin, actually ducted fan, yeah. So I borrowed a ducted fan unit from our next door neighbor, who happened to be the guy that taught me how to fly. I talked about on our one of our very first episodes and then convinced my mom and dad to buy a matching fan unit so I could have twin nitro ducted fans on this thing. And yeah, it was my. That was my first.

[00:19:26] And most memorable scratch build. So how big was this? I mean, like it wasn’t terribly large, I think. I think, if I remember right, I think I tried to scale it such that the wingspan was roughly 48 to 50 inches, I think, because I was using small. I was using relatively small fan units then.

[00:19:44] The length of it would have been pretty good, because I just did a quick google picture and it looks like a- yeah, it was pretty long- like that blackbird. It looks kind of like the archangel- yeah, kind of, but not even close it. It has the same basic shape, it just doesn’t have the two little wings.

[00:19:59] In the front. People on the internet are going to tear you to pieces for that? I hope. I hope not.

[00:20:04] Because that’s what: they are not even close. What do you mean? They’re not close, not even close.

[00:20:08] The, the firefox has a very skinny, narrow fuselage, and then the wing, while being somewhat triangular shaped, yes, but it’s not rounded like the smooth, like the blackbird, oh, okay. Well, in my defense I was:

[00:20:23] Just looking at the top down view, and that’s what made me think of the blackbird. Yeah, still not.

[00:20:29] Even close. So maybe a concord- well, it probably has- has more in common. The, the mig and the concord probably have more in common than the mig and the and the blackbird. Blackbird has smooth kind of a, while the, the cockpit, the window was angular, the, the nose itself was actually very smooth and the wings were kind of rounded and smooth, didn’t have any sharp edges and the wing like. The real difference is in the head-on view like: so the mig 31. It had kind of a gull shaped wing, so the wing

[00:21:01] Went out and then the at the tips, it kind of went down kind of like a kind of like a corsair in reverse. Oh okay, if that makes sense. Yeah, I have a blackbird wings straight, so okay, well, but anyway okay.

[00:21:13] So it’s the basic triangular shape with a long point coming out of the end. How’s that? Can we go there?

[00:21:19] Yeah, we’ll, we’ll agree that. That’s if we had this similarity, if we had to pick any airplane.

[00:21:24] That it’s close to? Would that be the closest one you’d pick or not? Either the blackbird or the concord.

[00:21:29] Actually I, I would. I would probably pick the xb-70 valkyrie. It’s probably more in common with that than

[00:21:35] Anything else, oh well, if I knew what that looked like, then maybe that’s what I would. Maybe you should.

[00:21:39] Google it, but anyway. So, yeah, it’s not like a blackbird, and so fuselage was we. So the wing fan was, I think, 48, 50 inches, and the and the- yeah, the length of the fuselage I think was- was a fair amount longer. If I recall, it was like another 10 to 12 inches longer, so 60 inches or so, that’s. That’s a good size plane for a 12 year old- 12 or 13, however- I think I was 13 actually- but yeah, for pretty good project for a kid of that age, and expensive too, I can imagine.

[00:22:14] Yeah, I mean, mom and dad really went out on that one for me well, and they got it for half.

[00:22:20] Price right, because they didn’t have to buy the other engine, right, exactly. So that’s, that’s nice, yeah, but like, so what? What goes into building from scratch then? Because you did you have like a three view set of plans, or were you just watching the, just watching the movie? Yeah, so you had your.

[00:22:36] Little, your, your black and white tv was on well, so it wasn’t a movie that we watched at home. No, really, it was a movie that I we watched in theaters, because so you had to go and

[00:22:50] Then like do drawings or something while you were there exactly. Wow, yeah, I think I watched the movie.

[00:22:55] Three times the first. That’s pretty good for three times. Well, what really? So okay, so long, I’ll try to make a. I’ll try to make a really long story short. I saw the trailer for the movie- actually I saw the poster for the movie outside the movie theater and it had a picture, kind of a front three quarter view, of this airplane. I was like that is the coolest thing I’ve ever seen and I was fairly new still to the hobby. So I was like airplanes are awesome, right, so well, you’re still.

[00:23:26] That way now, though, by the way. So it’s true, the age and the hobby doesn’t change things. No, it didn’t.

[00:23:31] Anyway. So I saw the, I saw the, the poster for the movie, instantly hooked, knew I wanted to either have one or build one of these things myself. Just because it was so, it was just so far out looking. So when I went to see the movie the first time I actually went with, I went with my, my, my grandfather, and I took a. I took a piece of paper with me and a pencil and every like shot, I mean like I, I kind of went there. I recall I had like a basic sketch of the airplane based on

[00:24:07] What I saw on the movie poster and I just sort of modified that as I watched the movie the first time.

[00:24:15] So I can’t remember if it was after the first time I saw the movie or the second time I saw the movie. One of those two, I figured out which about how big I wanted it to be. And all the while I was talking to my neighbor, the rc guy, and I had a lot of help from him. I mean, yes, yeah, I built the thing, or whatever. But I- he, he gave me a lot of input, like where he suggested I put a CG and that’s the one thing I was going to ask, sort of that sort of thing. Yeah, after I decided on what scale, roughly what size I wanted to the airplane to be, with his advice,

[00:24:49] Then I knew how, how much detail I wanted. Like did I want the wing to actually have that shape, or did I want to simplify the airfoil, to make it a little more?

[00:25:02] Likely that it would fly what I mean? Yeah, so I did take a few. I mean it’s. It’s not a real airplane, so anything I do is going to be taking a liberty. Right, I’m not designing it after a full scale, a real airplane, yeah, but I made the wing relatively thick, airfoil wise, and I- and I think I probably made it a little bit longer wingspan than probably it would have been intended in real life. Had it been a real airplane, well, do you think it would have flown in?

[00:25:30] Real life, with the proportions it had on the movie, given today’s computer computers and computing.

[00:25:37] Power, absolutely okay. I mean, I guess, planes that are even stranger looking than it fly. Yeah, and I guess.

[00:25:43] Even back in the 80s, that’s the- the stealth fighter was around in that time, so that goes back.

[00:25:48] To the 70s. So right, so yeah, okay, but yeah, I. So after the third time I watched a movie that was the, that was the time I really focused on the details: what the shape of the canopy looked like, what the shape of the actual, because there’s there’s a lot of generalities in the movie, like they don’t present you with a nice clear frontal cockpit view ever in a movie. So I had to sort of guess what I thought it looked like and if you google it now, there’s all sorts of artists, renderings.

[00:26:20] Of it and it looked way cooler than what I came up with as a kid. But, yeah, I watched the movie three times and each time I came out of the movie with more details and, yeah, factor that into my design. And I drew the plans by hand that I eventually built from with a- yeah, with a pencil, and

[00:26:39] Straight edge and a slide rule. I didn’t have a slide rule, but so how did that fly? So did it fly.

[00:26:47] It never flew okay. It got really close actually. Yeah, so back then. So this was in another little town here nearby here where I grew up- we had approval from the airport authority that our club could fly at the airport off of the runways, which was awesome, because this wouldn’t that be nice. Yeah, this thing being an a nitro ducted fan- anyone who remembers flying those back in the 70s and 80s- they eat a lot of runway. Once they’re airborne, you get air moving through there.

[00:27:17] Then they develop the thrust any, but static on the ground they don’t develop much thrust until they start getting air moving through them as the airplane moves through the air. So that was nice. So we had roughly 2800 feet, I think, a runway that we could use, but I was never able to. Well, I got it light once, like I actually. I think it actually came off the ground a little bit, but not a lot, not a lot, and I think I was running out of runway. So, and like I said, I had a lot of help.

[00:27:50] From mike- his name is mike- running out of a 2800 foot runway. Oh yeah, yeah, wow, looking back, I’m pretty sure it was underpowered, like even for a ducted fan it was. It was underpowered, yeah, and heavy. It was really, really heavy. So I’m afraid that if it had actually gotten airborne probably would have snap rolled on takeoff and destroyed it, but it didn’t. We never got it to that point and I think the summer was over by the time I got the project finished and we tried to fly it a couple times and then back to school and then I couldn’t, couldn’t, devote any time.

[00:28:25] To, to flying it or trying it, and it sat in our basement for a few years and then, finally, I took and took all the stuff out of it and I think I finally threw the airframe away, because

[00:28:35] Oh man, that’s too bad, but that it was a good learning experience. So would you do a scratch build again? I would you? Yeah, I would like to attempt that again.

[00:28:47] Actually, with today’s electric ducted fans and how much power they make, I’m pretty sure you could build that thing light enough to fly. Well, I think you ought to.

[00:28:55] Yeah, maybe someday put that on your list of things, yeah, yeah, because it’s such a short list, right, we have so nothing, few things, nothing’s coming up. I mean, yeah, we don’t have any plans, but yeah, so I’ve.

[00:29:09] Scratch built once and kind of what goes into scratch building is basically you: you start with an idea and you produce everything to include the plan that you eventually build from.

[00:29:22] So that’s the difference between scratch building and plans building, and I that makes sense, that I fully can understand that. Once you kind of explain it, do you have any advice for somebody that might be wanting to start their own scratch build? Yeah, don’t, don’t let.

[00:29:42] Don’t let what’s out there discourage you from designing something new. What I mean like even, let’s say, you want to build a p51. I mean, yeah, there’s lots of good kits out there, there’s lots of good plans out there, but there’s nothing out there that says you can’t design your own.

[00:30:00] Plans, even for all the ones that have been designed already. That means somebody is designing it already, right? So I don’t know if that made sense. I think I know what you’re trying to say. There’s, even if there’s a hundred of them out now and there’s another one that comes out, that means somebody started from scratch and doing it, so you might as well do the same thing on your.

[00:30:19] Own, right, right. So anyway, don’t don’t be discouraged by what might already be out there and don’t be afraid to, don’t be afraid to try something unique, like, like, as a kid, me doing this firefox thing, you, I mean if, if you can imagine it, you can build it. I mean, I know that sounds really, really cheesy, but no, it’s true, but balsa is so versatile you can build almost.

[00:30:44] Anything with it. You can build it, but can you make it fly? So what do you think of like if you’re wanting to get into doing something like that or like that? What do you think of starting, more inexpensive and, instead of like balsa for ribs, for formers and all that, maybe like using foam?

[00:30:59] Yeah, I mean so I wouldn’t start a scratch build as your very first RC airplane. I mean let’s just, let’s just, let’s just start there. Let’s at least have a basic, a basic understanding of how an RC airplane works by and the construction, by having flown one at least a few times. Yeah, so yeah, I wouldn’t, I wouldn’t do a scratch build as your very first RC airplane. But there are some things like you mentioned, starting maybe with foam first. That’s a good idea.

[00:31:33] Because foam is cheap and you can. You can proof a concept pretty quickly nowadays, like back when I started with the with that scratch build there foam board was something you put your science fair project on. It was heavy and it was had the cardboard backing. Yeah, I mean, we didn’t build airplanes out of foam back then. Now it’s so light and cheap that, yeah, you can. You can proof a concept pretty quickly.

[00:31:57] With foam. Yeah, the cheapness is nice because, like literally, if you do a profile, saw me the speed at.

[00:32:02] Which you can. You can build something out of foam is crazy 10 minutes. Yeah, like profile foam is, if you.

[00:32:08] Have it done right. You can be built and put together and literally putting the airframe together in 10.

[00:32:13] Minutes, right. So I would start like: if you have an idea of an airplane that seems like it’d be pretty cool, build something smaller than you intend out of then. Then you intend your eventual project to be, and make it out of foam and that way you can sort of play around with CG and you can figure out where that thing is going to probably fly the best. Yeah, depending on.

[00:32:35] The shape of the wing and all that sort of stuff. And if you crash a piece of foam you’re out not very.

[00:32:40] Much compared to a balsa. You’ve learned something and you’re not out. Yeah, like you said, you’re not out. Potentially hundreds of dollars a balsa. Yeah, so that’s good idea. We’ll have to do that sometime, yeah, yeah, start, start, start small and don’t don’t be afraid to try something different. There’s lots of, there’s lots of neat looking airplanes out there in foam that I would love to.

[00:33:01] See, made out of balsa and bigger. So a lot of neat foamy airplanes that you’d like to see made real. Yep, instead of a foam, bring it over to balsa. Exactly, I got it. Come to the, the real side of airplanes. I’m just joking. Not that we have anything against foam airplanes. We have a lot of friends that fly foam and I have foam airplanes. Well, that’s true. I guess I do too, I mean, but I don’t hate them, no, I just prefer balsa. Balsa flies better, I mean. Well, I think so, I do too, and I’ve flown

[00:33:33] Both. So you have, yeah, you ready to move on to an email? Sure, okay, let’s do it. So we have one I want to cover today, and this is. This is one we kind of covered a little bit before, but I want you to get back into it a little bit. Okay, it’s a quick one, okay. So kirk says: I really like you want me to hold that over here so you can focus on it. Old man, no, I’m fine, I just I couldn’t see because the microphone was in my way. I can see up here and I can see far away, so I don’t need.

[00:34:09] My cheaters. All right, he says. Kirk says I really like to listen to your podcast. Can you talk about how to convert a gas engine for from a weed eater to an engine for an RC airplane? Thanks,

[00:34:20] Well, it just so happens, you’ve done it. Yeah, I have a little bit of experience with that. Yeah, so, basically, to convert a weed eater or well, let’s, let’s say, a Ryobi engine 30 cc, just for grins and giggles, okay, for example a Ryobi 31 cc, 31 cc. Yeah, it’s actually. It’s actually quite simple. You disassemble everything that’s not engine, right, so you take it out of the weed.

[00:34:52] Whacker and you take everything off of the engine that’s not clutch, flywheel, flywheel, flywheel, especially if you’re going to convert it to electronic ignition, which I recommend- and then start with shaving things off that you’re not going to need because you want the thing to be as light as possible. So on the case of the Ryobi, it had a really, really big metal part of the casting of the crankcase was part of the. I think it was a magneto mount. It was really big and heavy. So I cut all that off and smooth it out as best I could and, luckily for me, the Ryobi

[00:35:28] Had an actual back plate, a four a four bolt back plate, kind of like a regular rc engine. So I just used that to make a plate for the mounting with standoffs. Sometimes you’ll get lucky and some of these gas engines have lugs on the side of the crank cases, just like model engines do. So if you have that, then it’s just a simple matter of buying a mount to fit it or fabricating your own mount or whatever. But you’ll have to figure out how to mount the engine.

[00:35:58] So that one, that Ryobi one, that is a long engine. So do you need to look well like because it’s long.

[00:36:05] Because it’s rear exhaust, because the motion is on the back. Yeah, you’re right. So is there anything?

[00:36:11] You need to look at, or is there anything that makes certain weed eater engines or chainsaw engines better as a candidate for conversion? Like: would you, if you’re going to do it again, would you still use an engine like that or not? Because, honestly, that is a long, long engine. It is long, I mean it was.

[00:36:30] What I had sometimes, sometimes you’re, you’re limited as to what you have on hand or what you have available to you. Obviously. Obviously there are ones that make better conversions than others, and what would you look for then? I would look for something that is, that is, that is literally an engine mounted into a, a, an implement, right. So this particular deal was not that case. This engine was sort of overall part of the whole. It was an integral to the, to the implement itself. So there,

[00:37:07] Was a lot of shaving of pieces that I had to do, like a lot of the like, for instance, pulan- I think I’m saying that right, pulan- yeah, chainsaws they use- and I’m probably going to get it wrong, but I think they use kairitz engines, which are very high quality, german nicosil liners, blah, blah, blah, but they’re, they’re separate, they’re like an engine that is mounted into an implement, just like you would take an engine and mount it into an airplane. So they’re sort of they sort of lend themselves better.

[00:37:39] To conversions because there’s not as much stuff cast into the crank cases. I don’t know a lot of what makes like. I don’t know a lot of brands, like which brand makes a better conversion than the other one because I’ve only converted the one that I did. Well, not necessarily brand, but as much as

[00:37:57] Like a setup like that. One has a rear exhaust, right, so would you prefer to look for one that doesn’t?

[00:38:01] Have a rear exhaust. It depends on the application, like if you’re going to put that engine in a sleek like a fighter style, like mustang or something like that. Yeah, you’d want an engine just like that, because then the exhaust is behind and the carburetor- I believe is- is behind also, so it’s very streamlined. It would fit in that skinny nose really, really well, okay, and if you’re scratch building, you can put that firewall wherever you need it to be, no matter how long the engine is. True, what I’m saying. Yeah, so it depends on the application as to as to, but

[00:38:36] Generally speaking, I would prefer a side exhaust engine because they, like you said, they’re shorter and easier to adapt to airplanes that are already designed. Yeah, I think if I measured that one.

[00:38:48] If I remember measuring that one, right from the back of the standoff to the front of the hub, yeah, it was what? 14 Or 15 inches, crazy, it was long. Yeah, and if I recall, I think I made the standoffs.

[00:39:00] The bare minimum so that you would not have to drill a hole in the firewall for a carburetor to get air. Like, if, like, if, oh, like. If you mounted it without a hole in the firewall, there would still be enough gap for the carburetor to get hair. It could probably shorten the.

[00:39:17] Standoff some, maybe not much, or when I muffler too. Yeah, that’s right. It just barely cleared by almost like an eighth inch, I think, is about all it was. Yeah, so, but anyway. So, yeah, start by.

[00:39:29] Getting rid of everything that’s not engine. And then, if you’re going electronic ignition, which I highly recommend, either if you’re skilled as a machinist or if you have access to a lathe and stuff like that, it’s not hard to machine your own prop hub, which I did. Yeah, that looks very nice because I happen to be a machinist at the time, but if you’re not, there’s a lot. There’s several companies out there that provide parts already made for popular conversions, and I think the Ryobi.

[00:40:01] 31 Was on, I think. Ch ignitions made adapter parts aftermarket so that you could convert engines like that to electronic ignition. Yep, but anyway, if you’re handy with a lathe and metalworking, not hard to do. And then you’ll have to sort out how you want to mount the hall effect sensor and that’s the thing. So you got a tiny magnet in your prop hub and basically I just counterboard a little hole and epoxied it right in the hub, and so is there any special place that?

[00:40:31] You put that no, because you’re going to time the engine anyway and you’re going to mount your hall effect sensor wherever it needs to be so that you get the timing you need, and I’ll talk about that in a minute. Oh, okay, I understand now, but yeah, so on, I think on the Ryobi- I think I had once I machined the hub, I think I had to file a flat, for I think there’s a woodruff key, I think on the crankshaft to hold everything, because it’s not a tapered fit, okay, it just slides over, I think, a woodruff key. I don’t know, at any rate, so you’ll have to figure out how you’re going to mount.

[00:41:04] That hall effect sensor that picks up that magnet as it, as it rotates underneath it. And I think on the Ryobi, I think I epoxy jb welded the sensor to a. I think it’s a hose clamp, because the crankshaft snout it is was square, it’s not a tapered snout, so I could get away with just a hose clamp, right, and it made easy timing adjustments that way too. Hey, whatever works right, right, so? So yeah, start with a, with an engine that you have access to get rid of everything. That’s not engine.

[00:41:34] Figure out what you’re going to do for a prop hub and then get yourself an ignition, from either ch ignitions or rc excel- there’s quite a few. You can even use a dle ignition, because they all kind of set up the same way, especially the modern ones- and then you’ll have to set the timing, and to do that you’ll need our tool of the week. It’s time for rc plane labs. Tool of the week, a degree wheel, which was easy enough. I made my own. I think it’s about eight inches in diameter.

[00:42:09] You just basically plot out a big circle- eight inches- and then make your 360 degree. You’d probably get away with five degree increments, just like a clock right, and then you got to mark every five degrees and you’ll use that to set your timing to 28 degrees before top dead center. And what that is you’re setting the magnet under the hall effect sensor at 28 degrees before top dead center. So you basically what you do is you, you get the engine over to where it’s exactly, top dead center.

[00:42:39] Put your degree wheel on there, put the zero mark on something that you can, that you can reference. I think I made a little piece of wire that stuck out off of one of the head bolts and would point to the zero on my degree wheel, and then I just backed it up to 28 degrees and that’s where I lined up the hall effect sensor under the magnet or over the magnet. Oh okay, yeah, 28 degrees. Yeah, that’s kind of the standard, 28 degrees plus or minus. Some engines run better a couple degrees advanced. Some run better. Not, that’s just, it’s something you can take her with. But 28 degrees generally speaking, yep, where we

[00:43:13] Start them and that’s really all there is to it. The carburetor that comes on them is usually a good quality walbro carburetor, which you don’t need to change unless it has a primer bulb, and then you might want to get a either block that off or get a different carburetor that doesn’t have the primer bulb. And why is that? It causes issues, especially, I think. I think it’s when, when, when you go inverted, so on these implements, they’re only really designed to be run upright. I guess chainsaws you can get away with getting them on their side or whatever, but if you get them,

[00:43:46] Upside down. Something to do with the primer bulb takes away the carburetor’s function to pump fuel for some reason. I don’t know why that is. I don’t know the physics of it. All I know is that a walbro- I think it’s a 532- is a direct bolt-on for almost every other pump or primer bulb equipped primer bulb, equipped carburetor. I think it’s a 532. Okay, anyway, we get on the forums and in the other forums. There’s lots of information out there, but it’s it’s easy to do. You can, you can convert one of

[00:44:20] These things if you have all the, all the pieces you need, pretty, pretty cheaply actually, I think, not including the purchase price of the of the weed eater which was used. I think I had about now. Granted, I made my own parts with the ignition. I think I had about 28 bucks in that. Conversion on that ignition is garbage. It is, it is and it was a cheap- I think it was a hobby king ignition which. So when did you do that, by the way? Oh dear, if I had to guess, I’d say it was probably.

[00:44:54] Sometime around 2008. Oh, so 2008 or 9, maybe really not that long ago. Yeah, like, I mean, for some reason to me it seems like it would have been like eons, but yep, that’s not. I think there’s video of it running on youtube somewhere. Yeah, maybe you can find it and post it on the forums or something we’ll see. Oh, but speaking of that engine though, so if it’s that old, fine, but we talked last week, I might be, or I might find a use for it, yeah, which brings me to my next question. Okay, so

[00:45:28] If, okay, if I use that and do what I was talking about doing- double sizing the elder- okay, that’s going to take that airplane to a 130 inch wingspan, huge, wide. We’ll say why it’s a large wingspan. Yeah, so what denotes a big airplane, like if we’re, if we’re talking about size on airplanes and stuff, what denotes the size on an airplane? Because technically that’s going to be a bigger wingspan than my yak, I mean, would it be scale? No, because the elder is not a real airplane.

[00:46:06] So you can’t talk about scaling a plane if it’s not a real airplane, that’s true, but I mean, like, the wingspan on that will be wider than my yak, which was the biggest of our fleet, right, but that’s not a big undisputed, I would say, what do you mean? So your yak 122, 6, 126 inches wingspan, yeah,

[00:46:28] Undisputed king of our fleet size wise, not my point. No, no, no, follow along okay. So if I were to, let’s say the elder project was mine and I built the elder at 140 inches, let’s say okay, and I put a 50 cc on it, would that then be bigger than your yak? I think. I think that depends on if it’s disputed or not. Right, because obviously the wingspan would be bigger. I guess I don’t know what you mean by

[00:46:59] Undisputed and disputed like if, if, if you just said: oh yeah, your airplane is bigger, then my airplane’s.

[00:47:05] Bigger. It’s undisputed, oh right, but that brings us back to what denotes size of airplane. That’s a good question, because I would not consider that to be a bigger airplane than the yak. Like what? If okay, what?

[00:47:20] If I let’s say I wanted to buy a biplane, okay, and let’s say the wingspan of the biplane, it’s a.

[00:47:26] Biplane. Okay. So let’s say, let’s see where we’re going. Yeah, let’s say, the wingspan on the biplane is.

[00:47:31] 115 Inches, let’s say. That would make it a much bigger airplane. Well is it, though it’s a smaller.

[00:47:38] Wingspan than your yak, but the fuselage would be bigger, because if it’s a biplane, well I know they’re usually smaller rather than bigger. No, no, I mean if you’re so, the fuselage would be bigger if the wingspan is that big. True so, but the wingspan is smaller, I know, but there’s two wings.

[00:47:58] But what? How do we do then? Double the wingspan, and then it would just be the undisputed king. Right, so is.

[00:48:03] It fuselage length, then well, I mean that I guess that would more denote like the size of an airplane.

[00:48:10] Right, well, probably, but like a shorter fuselage would, I’d be able to transport mine but not yours, because yours would be physically too big for me to transport. So then would that then make yours again bigger because the fuselage is longer? Or do we go by engine size- yeah, what? Or do we go by weight, like if, if the if my big by my big imaginary biplane weighed 46 pounds and your yak weighs 42.

[00:48:43] Pounds, which one’s bigger? Yours has a bigger wingspan, but mine’s heavier. What I mean? I, I, I think I.

[00:48:50] Might have to go by weight, the more I think about it. Yeah, or in what if they use the same engine?

[00:48:55] They both have 170s da 170s. Well, but now let’s say that mine’s a little bit heavier, but yours is.

[00:49:02] Bigger wingspan, and but we can’t go by weight then, because if it’s a longer fuselage and a bigger wingspan, what if you build heavy or just want to throw a one pound weight in there to make your airplane bigger? Yeah, that’s a. Oh, that’s going to be one we got to think about for a while. There’s

[00:49:20] Potential. I mean we could get to that point. I mean we probably ought to sort the rules out now, okay. So that means I’m just saying eventually, someday there we could come well. I mean, even with the elder, I mean the elder project, if it comes to fruition and we build it the way we’re planning on building it, would it be bigger than the yak? I mean physically, wingspan wise, yeah.

[00:49:47] All right, guys. I mean, is it a bigger airplane? So reach out and let us know what you think.

[00:49:51] Because I don’t know how to think on that one. Yeah, I would be interested to see, see some other, some other perspectives, because I mean what? What truly makes one airplane bigger than the other?

[00:50:03] What if you build- hmm, here’s a good one too. Okay, what if you build a big airplane out of foam? Yeah, if it’s just made out of foam, does that make it not count? Yes, no, but I mean like seriously, like I’m not even willing to talk about that, okay, okay, then put a kibosh on that one. Yeah, but you can do wide wingspans on foam pretty easy, but well, I mean,

[00:50:28] What makes two strikes against it? Right, it’s foam and it’s electric. Oh, come on, I’ll give you half of.

[00:50:35] The strikes doesn’t count, okay. So what if you have a big 170 cc equivalent electric motor? Then

[00:50:42] It’s still electric, which is awesome, which is doesn’t count. No, we’ll have that argument later, but yeah, we got to figure that out. Yeah, I would like to know what our listeners think. Like: what in, in a, in a contest of whose is bigger, what parameters makes an airplane bigger than the other? That’s I would be interested in, in knowing, and I guess at this point, the only thing-

[00:51:06] That matters is: I don’t care how you’re, you’re choosing, I win. Well, technically, you win right.

[00:51:12] Now, because you- that’s what I just said- undisputed biggest airplane of the fleet right for now.

[00:51:17] Wingspan length: motor size: yeah, weight. Weight, yeah, I mean undisputed. I like I don’t come close on any of those now. Is it bad though, like with bob’s airplane, that big biplane, oh, the big yellow. I what I love that airplane. I do too. But I was very happy, very happy to hear it was a 150.

[00:51:39] I mean, come on, okay, oh, but what if it was a 170 then? And that’s a big one, hey, I don’t know. Okay, let’s say it had a 170, okay, and let’s say it weighed 48 pounds. I’d have to weigh mine again just to be.

[00:51:54] Let’s assume that weighs 42 pounds, then he’s gotta be, he wins. I mean, his wingspan is shorter.

[00:52:00] But his fuselage is bigger. Yeah, well, I’m depressed now, well, but it’s got a 150 on it, so you’re safe.

[00:52:08] Okay for now. No, actually we need to talk to him and find out how big that is. Yeah, because I don’t.

[00:52:15] Need to get him to fly it. Yeah, well, fly it myself, because I’m fine with that flying it, I still want.

[00:52:21] To be there, by the way, I do too well, I know if you want to fly it, you’re going to be there, but I

[00:52:25] Mean, I want to be there. Oh, I got you. He fly. By the way, we were talking about being comfortable with big airplanes. I don’t know if this is show worthy or not, but he also flies that big cap now regularly. Oh, the one I flew for him that day. Yeah, he’s had it out like three or four times now. That’s a nice airplane too. I love that airplane. Huh, still smaller than yours, though.

[00:52:46] Like I’ve said it before, I think that’s a 120, I think, oh, is it that big really? I thought

[00:52:51] It was a 100. I could be wrong, you might be right. It’s a da, I know that. Yeah, do they make a 120?

[00:52:57] They do make a 120, I think, so they make a 100. I bet it is a 100 actually either way, but yeah, no, I still would like to have one, smaller, like I would love to, one of these days, talk you out of.

[00:53:10] Your yak 50 cc, yeah, and I mean that’s right now. You really don’t have anything that I want.

[00:53:22] I know, I mean, if I’m honest, well, and it might not have to be a trade for another airplane, oh well, okay, it could just be that I don’t know, who knows, but well, I do have. I’m just saying, if it goes.

[00:53:33] Away 50 cc airplanes. Yeah, I mean I could unload one if I, and especially if you get a bigger one.

[00:53:40] If the right deal, yeah, why, whenever this day happens, I would have to get rid of it, because

[00:53:44] I would have to have some place to put said big airplane. Well then, let’s, let’s find a big airplane.

[00:53:49] For you. I’m working on actually. No, let’s not do that now, because I don’t have the money for a 50 cc.

[00:53:55] Yeah, I, I really don’t have the money for a big airplane, but it’s one of these days. Oh, what’s.

[00:54:00] Gonna happen to where we’re both gonna have to be a competition. Yeah, yeah, and perhaps one of these days, both of these airplanes, or this airplane and whatever big one you’re talking about- to fly together. I was gonna say you’re gonna look small compared to whatever gosh. Can you imagine I wouldn’t mind having a 50 or a 50 sometime- 14, 15, 16 foot wingspan, even like a big cub. I think that would be fun. What was the one hempel? Yeah, what a hempel cub. Is that a 50? Yep, and that’s 17 foot or something like that. I mean, that’s just huge. I cannot imagine, but I saw somebody flying one of

[00:54:35] Those ones just like a big kitten, I mean so docile, and just a great lazy sunday flyer. Well, like we.

[00:54:43] Always say: the bigger they are, the better they fly. Usually, however, the bigger they are, the harder.

[00:54:48] They fall and that is not a good thing. Well, that’s true. You don’t want bigger. They are, the more

[00:54:54] Expensive they are. You don’t want to re-kit it. Not something that big, we’ve all. It takes a lot of.

[00:54:59] Trash bags there. Yeah, that’s when you just sweep it up and burn it. Yeah, walk away and forget it.

[00:55:06] Ever happened. Take what you can out of it and just light. It sets it on fire. Right there, all right, that’s. That’s pretty much pretty much all my notes. Yeah, I think that’s all I got to go through this week too, so okay, so just a quick reminder: if you guys- once again, not to, not to beat a dead horse, but if you like what we do and you and you’ve gotten something out of it and you want to show us some love, become a patron, go to go to patreon and sign up to show us some love. And also, I would really like to hear your guys ideas on what makes an airplane.

[00:55:39] Bigger than another one. Yeah, I’m curious on that too. Yeah, so email, write us, do whatever, send us and.

[00:55:46] Have a look at that article I posted. It’s really good. There you go all right. Well, knowledge is power. Just saying what, where did that come from? It’s also from 80s, I think, schoolhouse rock.

[00:55:59] Sorry. Oh my gosh, all right, I’m done. I’ve heard of that but I’ve never seen it. Google it, you and google.

[00:56:07] My goodness, all right. Well, I’m finished. Anything else and everyone, all right, have a good night all.

[00:56:12] Right, good night, bye. We hope you enjoyed this episode of the RC Plane Lab podcast. For topic suggestions, to ask questions or to give anything back, connect with us at rcplanelab.com or email us direct at either Ron at rcplanelab.com or Tom at rcplanelab.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 you.