Projects New RC Project that has me stressing

Derek

Well-Known Member
Ok, I think I may have bitten off more than can I chew with this "brainstorm." I clearly dont have the experience needed to be doing this but I dont want to give up on it due to the amount of progress that I do have done.

A while ago, I decided that I was going to scratch build an rc plane with a 20' wingspan. This plane will be made from Dollar Tree foamboard (double walled for rigidity). I have the fuselage pretty much done and I have the wing sections built but not completed because I want to run the servo wires and such inside the wing...of course.

Thus far, I have the wing built. It has a true airfoil, with inner ribs, equalling 20 feet long. My fuselage is currently 78" long but this may change later on to adjust the CG. My fuselage and wing, right now, weigh in at 9lbs 7ounces (4280 grams). I am looking for some help choosing a motor/prop/esc/battery combination. I'd like to run this plane on 3cell or 6 cell lipo's because that is what I use on my other planes and heli's.

Tony is probably gonna have a fit when he reads this post because I'm haunting him, again, with my ambitious inexperience. I've watched the video that he did using his Edge plane, "Matching Motor, ESC, & Battery", and it helps but I think I'm needing more input.

I'd really like to take my questions to the guys at my local hobby shop, only two miles away from me, but they are only interested in "making the sale" and they aren't real friendly to "scratch builders." It's pathetic!!!

I do have some videos on Youtube showing some of the build that I've done so far. If those would help, how can I post a link or URL so that you can see them? Or, maybe I need to make a short video of what I do have done and what I'm looking for. Some of my build videos were rather long due to the fact that I have a habit of "rambling on."

Anyway...I'm rambling on, lol. What can I do to help you help me?

Thanks in advance!!!

Derek
 

Tony

Staff member
Scratch building has to be the best thing out there because of things like this. It's amazing what you can do with simple foam board.

I will tell you this, you will need to run some kind of supports for 10' wings. It will also not like the wind at all. But it can be done. As for motor size, you are going to need something that will swing at least a 24" prop. This is getting into the large scale planes here and you may only find things for nitro in this size. The Senior Telemaster is only 12' and it uses a 60 sized motor. You will need bigger than this. I'm thinking you will need the big foot 110 or 160 motor spinning a 24x12 prop. You will be pulling about 2500w and can use up to a 14s pack. So you would be able to run 4 of your batteries in series on this bad boy. But you would have to get an HV 100a ESC minimum.

There will be a lot to go into this. Like you may want to think about doubling up the servos on your ailerons and elevator. That or you will have to use one kickass servo on each lol.

Bigger means more money, but it can be done. Just the motor alone will run you about $60.

As for posting videos, just go to the page on youtube where your video is playing then copy the link in the URL bar at the top of the window. YOu can also copy just the code just below the video and paste it on here. The forum will automatically embed the video on the forum.
 

Derek

Well-Known Member
I probably should have mentioned this in my first post. I'd really like to run two motors on this plane. One on each side of the fuselage.

I also don't want to fly this plane fast at all. I just want it to slowly meander around.....ya know...."Driving Mrs. Daisy" kinda thing.
 

Tony

Staff member
I don't think you have a choice but to fly this slow lol.

If you run dual motors, you can probably get away with two 60 sized motors. And again I have to stress the wing bracing.
 

Derek

Well-Known Member
Wing bracing is a definate. I'm uploading a video to Youtube right now that give a breif showing of my plane and what I'm looking for.

Once it's finished uploading, I'll get the video on here.
 

Derek

Well-Known Member
here is a 10minute video that I just uploaded to YouTube showing my plane and a few of my thoughts.


I could use the help.

THanks!!!
 
Last edited by a moderator:

Tony

Staff member
First thing is first. Lets talk about that support bar that you have. On the little glider that bar is not there for support, it's there to help hold the dihedral in the wing. It will not work the same on your big plane however. Because the strings are pulling up, it's actually only supporting the wing when it's on the ground. Once you get into the air, or even running down the runway, you will create lift with the wing which will be pushing UP on the wing making the wires on the one you have now go slack. The support that you need is more like what is on a Cessna.

I did see that you had PVC run in the wing and that will help out a lot for strength. But it will flex a lot when in the air. Maybe if you double it up or find some carbon fiber to put in there, it may support it's self on the ground and in the air. I will bet money even if you use carbon fiber that the tips of the wing will flex at least 3 feet up and down from on the ground to in the air. If you yank on this wing, it will more than likely break.

If you run a support beam like is on the Cessna's, it will help to keep the wing up when on the ground as well as help keep the wing from flexing up when in the air. The fuse of the plane needs to be about 10" from top to bottom at the minimum and no shorter than 10' in length IMO from what I have pictured in my head.

Running the dual motor setup is pretty straight forward and it seems that you have this under control. If this were my plane, I would plan on this thing weighing at least 25lbs AUW with everything ready to fly. With that said, I would not run anything less than the 110 size motor that I had mentioned before spinning a 19x10 prop. This is a HUGE prop and can take off a limb so you will have to be careful. Hell just the shaft on the motor is 8mm dia lol.

I sure wish you were down here because I would LOVE to be a part of this! That is one epic plane you are building and if it flies, that would be just awesome. I do want you to know, a plane like this is not covered by the AMA if something happens lol. At least I don't think it is. So make sure you are out in a field with no one around and keep it in an area where if it does go down, there is no one there.

Don't let it get to you. It took me a year to design the RCH Trainer and get it in the air. My Telemaster is still not done. If you are feeling overwhelmed, just put it aside and walk away for a bit. This build will more than likely be your most expensive yet. I'm thinking something around $500-$600 to get it done. But if it works, it would be so worth it!
 

Derek

Well-Known Member
You are quite right about those support lines on the glider that I showed. That principle will surely NOT work on my plane. In my haste, I had forgotten to mention that I'm planning on support lines on the underside as well to counter the lift...just as you stated. I am incredibly tired and I'm sure it is easy for me to leave out details. I apologize for that. The way that I see this this plane is that there will be 4-6 support lines coming down from the tower just to hold the weight of the 20 foot long wing. I'm also seeing 6-8 support lines coming from the belly to the wings to counter the lift. There are actually two different sizes of plastic tubing in the wing. The larger tubing in the center is for the wooden dowels to act as a spar and the smaller tubes are there because I have some fiberglass rods with threaded connectors that I will be using to hold the wing sections together. If you have some spare time, Tony, check out my other videos on Youtube, labels AXON Project. I have shown various steps of the build thus far.

You mentioned a 110 size motor. Is that electric or nitro?

This will surely be a long process and my Dad comes to help from time to time. He has less RC experience than i do, so you can imagine our conversations, lol.

As far as AMA goes...I'm not concerned with that part at all. I have two flying fields that are 100acres or more that I can go to. They are actually the same properties that I deer hunt. Wide open spaces. Without such areas, I probably wouldn't even attempt to build this plane.

And if it does work....if it works the way that I hope it does....this will be INCREDIBLE!!!

I'll post pics or vids of any major progress.
 

Tony

Staff member
The motor is electric. Below is the link to the motor and the ESC I would use on this build.

Motor - Tacon Big Foot 110 Brushless Out Runner Motor for Airplane (295KV)

ESC - HobbyWing C-Platinum-100A-V1 Brushless ESC for Trex 550/600 RC Heli and Giant Aircraft

HV ESC - New HobbyWing Flyfun ESC 100A High Voltage for Airplane & Helicopter

As for watching the videos, I will have to find time at the house to do it. I'm limited on my phone internet here at the base and those videos would kill me. But I will see if I can remember to watch it this weekend while I'm off and not searching or setting up an aquarium.
 

Derek

Well-Known Member
Thanks, Tony for the suggestions. I'll look into those.

You are on a base? I didn't know that. Good luck with the aquarium!
 

Derek

Well-Known Member
Hey Tony...I was looking over the spec for that Tacon Big Foot 100. It says something about 14S for lipo's. That's 14 cells. However, in the lower part, there were customer reviews...several said that they were running this motor on 8S and everything was fine. Can you, or someone that comes along this thread, explain why this is the way it is? That's all I need is something more to confuse me.
 

murankar

Staff member
With out looking at the motor specs I would venture to guess that the 14S is what the max voltage for that motor is. Now the more volts you have the lower your amps are. Now for those running 8S they probably have high amp rated esc's and the motor probably can handle the amps and still is able to produce the needed power.
 

Tony

Staff member
yeah, I work for the Oklahoma Military Dept. Pretty much they pay me to watch TV and run my websites lol.

- - - Updated - - -

And the 14s is the max voltage. You can run this on 6s but make sure to figure out your power draw. On a 6s setup, you will be pulling about 91 amps. On a 14s setup, you would be pulling 39 amps.
 

Derek

Well-Known Member
ok, that makes sense...I could follow the equations in your "Matching Motor, ESC, and Battery" video to find those values. Got it (for now, lol)
 

Derek

Well-Known Member
ok Tony....i'm back to harrass you some more. I'm really liking what I'm reading about that 110 that you suggested, I'm still undecided about the ESC, but the lipo's....hmmm, because I do already have a Trex 500, and it runs on 6S lipos...I'm thinking about using two 6S lipos for this plane of mine...maybe somewhere in the range of 3300-4000mah range and I can still use those lipos on my 500 (I think). The 6S is mearly just voltage...the power...and the XXXXmah is the juice....fuel tank. So...two 6S would make 12S, therefore less amps being used than if only one 6S and the flights on my big plane wouldn't be REAL long but it would also mean that I would be able to use one of those 6S lipos for my 500 and be able to fly a bit longer than my 3000mAh that I already have. Am I thinking this correctly?
 

Tony

Staff member
Yes and no on your question above. And I apologize for not being on here for a day. Interwebz are messing with me at my house.

If you run a 6s 3000mah pack (the same battery that both Lee and I use/used in our 500 and 600 heli's) you will get X amount of flying time. If you bump that up to 12s (two 6s in series) you will still only get X amount of flying time. You will also have to find a motor that will run on 44.4 volts and those ain't cheap. You see, you may be doubling the voltage, but your mah or runtime will stay the same with teh same current draw. Yes it will draw less amps, but the wattage will either be the same or be more on the 12s setup.

However, if you find a motor that will run on a 6s setup, you can run two of your 6s 3000mah batteries in parallel giving you 6000mah. This will theoretically double your run time over a single battery as well as double the C rating out of the batteries so you can use a bigger motor. But bigger pulls more power.

If it were me, I would run two of the 6s batteries in parallel for the flight time. 6s motors are out there and are power houses with the right setup. And as you stated, you can run the same batteries in your 500 so you are not having to purchase new batteries just for this plane.

I hope this helps. I have not gotten a lot of sleep, but the above makes sense in my head lmao. Let me know.
 

Derek

Well-Known Member
Yep...I understand that. I've not gotten alot of sleep lately either, so I may have left out some details in my previous posting. Due to your previous reply, I think I fully understand what you are saying...using the two 6S in parallel, paired up with that Tacon Big Foot 110 and 100amp esc.

Thanks again for the help and I'll keep you posted on any progress since you seemed to have a bit of an interest in my ridiculous, and hopefullly awesome, project plane. Get some rest!
 

Tony

Staff member
Bro, I'm interested in any project that you have going on. And one this big is just epic lol. You need some HUGE RCH decals on that thing hehe.
 

Derek

Well-Known Member
Hey there Tony!!! another question about my big plane. I'm hoping to use 7 servo's (2 for each aileron, 1 for rudder, and 2 for elevator). I was even thinking about flaps (+2 more servo's). I'm gonna get that 100 amp ESC listed below. Using that many servo's, I'm sure there will be a need for a BEC. How do I choose a BEC that will be suitable for my setup?

ESC: New HobbyWing Flyfun ESC 100A Opto for Airplane & Helicopter

Thanks!
 

Tony

Staff member
In all honesty as long as the servos can handle it, I would just use a Rx pack on something like that. It's just a 5 cell (yes, cell not S lol). that gives 7.2 volts. I don't know if I would use a 2s lipo because they are pushing 8 volts when fully charged.

If you want to use a BEC, then you can run an extra 2s or 3s battery as big as you want. Just make sure the bec is rated for the amp draw of your servos. 9 servos is a lot of draw so do your math.

- - - Updated - - -

This is the biggest one they have. 8 amps should be enough. Don't worry about the dual plugs, you can cut one of them off. their reasoning is stupid for putting two on it.

http://www.hobbypartz.com/ubube.html
 
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