Hi all, I'm in the process of building an ET-1 trainer to teach my 10 year old son CL and relearn it myself and I have a couple questions about it.  I'm building this out of Dollar Tree foamboard because I don't have coroplast, so I'm hoping it will be durable enough with the paper on, and I will use R/C control, so I can control the speed as well, hopefully it will fly slow enough to survive the inevitable crashes I'm guessing we'll have? 

Anyway, my 2 main questions are thrust angle and rudder offset, the plans I downloaded to cut the foam board did not seem to indicate either of these, can someone here let me know what these should be if required?  I built a couple CL airplanes when I was a kid and I do recall they always had outward thrust angle, usually in the form of a couple washers on the motor mount.  And they also had rudder offset to yaw the plane away from the center of the circle to keep line tension and control.  Any help here would be greatly appreciated, and I'm hoping to do a maiden flight this weekend if possible, thanks.

Scott

Larry,

Thanks so much for the quick reply here, that's very helpful, I'll probably get my "kit" glued up this evening.  I did find some instructions that mention a left hand APC prop, which I assume is big for keeping line tension with torque.  So I will have to look and see what I have in the way of pusher props that size, I know I have some pusher props, but I think they're quite a bit smaller than the 7" that my HK 2730 1700kv likes.  I may need to rethink my power system, and match it to my in stock pusher props? 

And I know the foamboard may not be as durable as coroplast, and I will likely use some tape and/or bamboo BBQ skewers to reinforce things as needed.  The good news is the foamboard at the dollar store is only $1.08 after sales tax, and one board will easily net 2 ET-1 "kits".  I may just cut another one before our maiden flight, so we have a replacement airframe ready to go.  I do expect my son to learn pretty quickly since he already knows how to fly R/C trainer planes pretty well, the round and round spinning thing could make for some dizziness and loss of control, but that's why we'll have R/C control to limit the lap count.  Thanks again for the quick help here.

Scott

I will probably still try and set it up with a pusher prop to get the torque advantage. And I expect it to be fairly light weight since I'm not planning on having landing gear and the foamboard is likely a bit lighter than coroplast.  And it just has to hold up for training 2 "kids", my 10 year old and myself.  I've built a few different R/C park flyer foamies, so I do have some experience with the building techniques and reinforcing high stress areas, but I have not used Dollar Tree foamboard before they were all blue foamboard without paper coverings.  The paper covered foam seems pretty stiff already, but I'll probably do some packing tape or strapping tape reinforcements here and there for piece of mind at least. 

I also have a 1/2a Sig Skyray kit that I'm planning on building soon as well, and it will be electric powered as well, since that's what I know best from my R/C park flyer experiences over the past few years.  I hope the ET-1 goes well and we can progress to the Skyray which I'm planning to setup to learn some beginner stunts.  Thanks again for the advice here, I'll try and post pictures before the maiden flight.

Scott 

Tim,

Thanks for the advice.  I think we'll try and get some paint on this before we maiden it to solve the sensitivity to wet grass, and I am very familiar with bending motor shafts on electric motors on some of my R/C foamies, prop savers can help sometimes, but they're certainly not foolproof, hard nose-ins will still bend or break motor shafts.  From my experience the prop savers work well for belly landings on planes without landing gear, but crashes are another story, sometimes they work, sometimes they don't. 

And I think if we enjoy the ET-1, which I fully expect we will, then I will probably want to get something more stunt trainer worthy. I've already looked at a few posts about electric Sig Akromasters, and I'm all but certain that I already have a suitable power system for something that size in my spare parts boxes, so the expenses for such an upgrade would be minimal. 

The Flitetest Bloody Wonder does look like a quick build, but I don't particulary like the look of it, and would prefer a fully symmetrical airfoil over the flat bottom airfoil that they show on the Bloody Wonder... at least for stunt training purposes anyway.   

Thanks for the tips, I'll look at the Flite Test site on sealing the foamboard.  And the lighted Akromaster sounds cool, I have an R/C flying wing with lights, but I have found that if it's too dark and I don't keep it really close by, I can easily lose orientation and have crashed it a few times because of this problem, but control line would likely be much easier to stay in control.  Have a nice New Year's if you go fly it tonight.

Scott

Well we don't have any "slimers" or the support gear needed for them, so we'll just go with the R/C CL, and we can cut the throttle if we crash, and hopefully save ESCs from frying?  I really expect my son to do pretty well with it because he already knows how to fly R/C trainers, so I think he will do well and not crash too much.