Foam Conversions: What did you do with your $4.00?


While out shopping with my sons a few weeks ago, I came across a cheap styrofoam glider. Normally I would pass these little toys by, as I consider myself a “big kid” and therefore deserving of more “big kid oriented toys. ( Read: $$)

This little glider though had a 4 ½ foot wingspan (pic1). One of the biggest toss gliders I have seen. I immediately thought about the solar panels I had purchased from www.allthingssolar.com. These panels are 10.5”x3.5”, and make 6V and 100MaH in full sunlight. (pic2)

I had been considering the possibility of using solar panels to enhance long-duration powered gliders for a while, but long duration gliders can get rather expensive. I don’t own one and this seemed like a possible candidate for cheap testing.

Upon opening the kit, made by Life-Like, I was first impressed by the extremely light weight of the entire kit. Then I saw the long, tapered nose and the blocky wing tip structures (pic3) to help with tip stalls and I began to see some real possibilities for my $4.00 investment.

I had a pair of JR-241 servos, ESC/BEC, and a Pico Rx. that had been living in the carcass of my J3-stick. I don’t really care for the flight characteristics of the J3-S and have already earmarked the wing for another project, so it went into the “corner of doom”. Newly armed with r/c fixins, I settled down to examine the foam plane in more detail.

I first assembled the plane to get an idea of CG, and possible control-surface mountings and dimensions. The plane balanced perfectly at approximately 140mm from leading edge. Unfamiliar with the proper CG for this plane, I took it to be the designed point. I also noticed that the plane balanced well on all 3 axis of rotation. Very nice for a $4.00 styro.

After marking the location of the CG on both top and bottom, I began the process of deciding what my actual flying gear was going to be. I had 2 battery packs that were not in use by other projects. 1 270mah 6 cell, 1 900mah 6 cell. The battery was going to be the heaviest component on the frame, so I decided to balance the battery over the CG. (pic4)

That left the area behind the battery for radio gear, placing it safe from the mass of the battery if I didn’t fly well. The area ahead of the battery could then be used for powerplant (pic5) or ballast weight.

After looking the frame over, I decide to mount the Rx and elevator servo semi-flush into the boom. That meant taking material out of the boom, (pic6) weakening its ability to carry flight loads and resist twisting. A light balsa radio compartment was built into the recess created and lite-ply servo rails were CA’d carefully into place. I had no foam safe CA, and ended up eating a chunk out of the edges of the foam. Not serious, but a good reminder that foam is much different structurally than balsa.

After finishing the radio box with a light sanding, I moved on to the tail. I had already decided to use aileron/elevator control, so making the elevators was simply a matter of cutting the recessed lines in the stabilizer. After cutting, the elevator pieces looked way too small to work well so a ½” balsa extension was made for each elevator half. (pic7) I made 3 revisions to the elevator assembly. I really like the final product, and think it was a cool way to insure proper rotation of the elevator. The first try (was a toothpick in a clear coffee stirrer. (pic8) It seemed to bind, and also flexed a lot due to the angle of the elevator rotation. The second prototype had a .047” brass rod attached to the rear of the elevators, this seemed to be a decent solution, but I didn’t like the way the elevator flexed at the tips of the wings. (pic9) The final solution was a .047” rod in a 3/32” aluminum tube. (pic10) Each assembly weighed .5g. With the low weight of the end pieces, I decided to rip out the toothpick/straw assembly and go to brass/alum angled to accommodate the angle of the elevators, thus eliminating the annoying bind in the control surface. Total weight added 2g.


[i]if someone can help me with getting the pictures online, I have gerat shots of the whole process.....

And what does this have to do with Electric Ducted Fans?!

Dose the fan instalation come in the second book ?

yes

Water,
Nothing personal, but this really belongs in the foamies or open discussion category.

Cheers,
Daren

[This message has been edited by Daren (edited 08-05-2001).]

I am strapping a KP-44 ducted fan, in 1 and 2 fan unit combinations, to this foam TESTBED airplane. It weighs almost exactly what I am shooting for with the A-7...

This info will be about the DF performance I can get with this plane on KP-44 Ducted Fans.

But since everytime I ask a question, instead of an answer I get a treatsie on what a miserable bastard I am for not knowing rules and regulations of Ezone posting procedures, posting too much, or in the wrong place, or altering the laws of physics.... geez. why dont you just answer the darn question? If I needed to be nagged for being an idiot, I would go wake my wife up.

I will tell you that the Life-Like 4.5' foam glider makes one hell of a flexable test bed, having SUCCESSFULLY flown a single fan on 6 cell 270Mah battery. The flight was brief, as I was not trying to set any records for the first flight, nor have I ever had any intentions of doing so at any time. It also flew a 900mah 6 cell sub C. The wing span on this glider makes it very stable for testing, and I am considering making a socket to fit a post that various motors could be easily setup and tested.

Like using the plastic rectangles from the mounting bracket on my stik, gluing them into a routed hole in the fuselage, so that a 1/4" balsa stick fit snuggly. Then make a very light balsa mounting bracket, with a the ability to move the motor mount plate back and forth several inches to make easy adjustments to CG. It and a few grams of weight, but I could throw motors , fans, gearboxs, whatever on fast and easy. Just strap to mounting braket, and plug into fuse on a balsa stick. Be easy to make quick adjusments to pitch and angle too.

I mentioned the solar panels because someone might think of a use for them. Sue me.

Is it a any of this a good idea, i dont know, I'm gonna find out.

Mr. Bullseye, the worlds easiest target

Originally posted by watersharer:


But since everytime I ask a question, instead of an answer I get a treatsie on what a miserable bastard I am for not knowing rules and regulations of Ezone posting procedures, posting too much, or in the wrong place, or altering the laws of physics.... geez. why dont you just answer the darn question? If I needed to be nagged for being an idiot, I would go wake my wife up.

Its because of your attitude in your posts, nobody is going to answer anything you ask if you keep acting like a child.
Maybe you should go wake her up, so we don't have to hear your whining??


[This message has been edited by Cue (edited 08-05-2001).]

?!?!?!?!?!?!?!!!!


What if I told you I am 13 years old. Part of the reason that I ask so many questions, and seem so ignorant is that I am ignorant. I am not stupid, I just lack the knowledge I require.

Cue, I really dont understand. And so you treat me like crap, and ridicule my ignorance. I hope that this hobby gives to you all that you give to it.

What if my son wants to try his idea about a flying alien. It's actually a cool idea in a silly little kid way. It would probably sell like crazy. Do you honestly think I would tell him to get online and go to "ezone.com" to get his questions answered? He is 6. He knows nothing about batteries or amps, or Lithium vs. NiMH.

Would I be out of line to think you would treat him the same way you treat me?

I bet a lot of guys have stupid questions. And I bet at least some of them never ask, for fear of getting flamed for their lack of knowledge.

I tend to write my thoughts pretty directly. If that bothers you, well, I cannot be responsible for your happiness. Dont read my posts, ignore my questions, whatever it takes to make you happy.

I personally really like to come upon detailed threads. I wish everyone would give more hard data on the things they build and try. It makes for interesting reading.

watersharer,
I wasn't trying to tell you that you posted in the wrong place. you made no comment about ducted fans in your original post. Sorry if I sounded rude or abrupt.

I don't think your Walmart foamy is going to relate to your A-7. Size and wingloading are going to be dramatically different. Your glider there has a 4.5 foot wing span. The A-7 is what, 20-30 inches. Although I'm sure it's working great for testing your fan and motor combos.

If you want to show pictures online their are a great many tutorials on the net for learning basic html. That way you could make a simple web page for when you get your Lithium Ion EDF flying. When you post a topic take a look to the left. You'll see UBB Code is On. Click on it and it will give you UBB code to upload pictures to the board. But they have to be on a server first.
Email me if you want more details.

Foxtrot

Foxtrot, you had a legitimate question, why would that bother me. It is the flame-post crap thats buggin me.

For the aileron assembly I chose to measure 6” from the tip stabilizer and 6” from the wing root. The wings were taped together bottom to bottom, and the styro between those points was removed to a depth of one inch. The ailerons ended up being 13.5” long x 1” wide. I had become a fan of the aluminum/brass fitting from the elevator installation, so I chose to use them in the ailerons as well. After fitting a flexible CA-type hinge in the center of the aileron ( just in case my homebaked “fittings” didn’t work out) with craft glue, I assembled the small metal fittings and carefully bored them into the wing and ailerons. I then removed them, placed a small drop of epoxy in the hole, and replaced the aluminum tubing. After the epoxy set, I measured a small section of brass rod, slightly smaller than I needed. The brass shaft would have a small amount of play but would not be able to work loose. I used the metal pieces for the torque tube and rod as well. On any heavier plane the brass rods are too flexible. But with the low friction hinges, and the light weight of the aircraft I felt they would be acceptable.

The mounting of the aileron servo was more of a challenge. The fuselage was solid, and required cutting a significant amount of styro to be removed. The finished fuselage came out really nice looking, I think. From above and below the plane, the servo and rods are not visible. But from the side, the dome of the servo, and the gleaming brass connecting rods can be seen under the wing, and are very striking. And to regain the lost structural foam strength, I bonded a balsa skid plate and tail plate to the under side of the fuse. The end result felt measurably stronger than the stock foam body had.

I had decided to build this plane as a high lift, lightweight test plane. Sorta a B-52 for my own little micro X program. And since I have been digging myself a hole with crazy talk about batteries and ducted fans and everything else in the world, I decided the first data would be obtained on EDF performance.

I don’t have the lithium batteries for testing. I do have a couple cheap primary Li batteries that will bravely meet their doom in the morning, damn, it is morning. The first uncontrolled test flights last night went very well. 3 powered glides on Nicads. The damn thing has a real nice descent rate. Flew all the way across the yard on a tiny handlaunch. The motor spins up fine, but at max throttle, the motor or the ESC cuts out. I think it might be the light gauge wire from the motor to the ESC. I am going to replace it with a heavier gauge wire and see.

The plane is finished, test flights tomorrow, and successful or not, I will annoy you all and tell you.

ok, I might have figured out the picture thing.

http://www.mycreation.net/microflight/

Originally posted by watersharer:
?!?!?!?!?!?!?!!!!


What if I told you I am 13 years old. Part of the reason that I ask so many questions, and seem so ignorant is that I am ignorant. I am not stupid, I just lack the knowledge I require.

Cue, I really dont understand. And so you treat me like crap, and ridicule my ignorance. I hope that this hobby gives to you all that you give to it.

What if my son wants to try his idea about a flying alien. It's actually a cool idea in a silly little kid way. It would probably sell like crazy. Do you honestly think I would tell him to get online and go to "ezone.com" to get his questions answered? He is 6. He knows nothing about batteries or amps, or Lithium vs. NiMH.

Would I be out of line to think you would treat him the same way you treat me?

I bet a lot of guys have stupid questions. And I bet at least some of them never ask, for fear of getting flamed for their lack of knowledge.

I tend to write my thoughts pretty directly. If that bothers you, well, I cannot be responsible for your happiness. Dont read my posts, ignore my questions, whatever it takes to make you happy.

I personally really like to come upon detailed threads. I wish everyone would give more hard data on the things they build and try. It makes for interesting reading.

The 13 year olds that are on this board have more patience than you and a better attitude, that is why you are getting rediculed so much.
There is nothing wrong with asking alot of questions, I know I have, but when someone gives you an answer and then 10 other people give you the same answer, and you post again acking the same question saying things like "your word isnt gospel" then how do you think people will react?
Then you whine about being a punching bag? you made it that way all by yourself.

YOU DO NOT TAKE ANYONES ADVICE OR ANSWERS and get very pushy when someone gets a little off topic, its your own fault and no one elses.
everyone has said good luck with the lithiums, but they don't think they will work which they more than likely wont, then you get mad at people for saying that ??????

you asked for it.

Originally posted by watersharer:
ok, I might have figured out the picture thing.

http://www.mycreation.net/microflight/

All I saw there was a shot of Mt. Rushmore...

Later,
David

Yeah, the web link is not working.


And Cue, if I am such a "crazy man" trying to rewrite the laes of physics, how do you explain the sudden surge in people posting links about "micro-edf's" and "lithium batteries". It would seem that at least a part of the time, the advice is more along the lines of rumor or supposition. Just because one guy says " them dang Lithium batteries dont dang work" does not make it true. As several people have shared personal experience using the Li batteries successfully, I am going to assume that most of the guys saying " it wont work" are wrong.

The guys who say " It wont work" and then follow that up with reasoned, logical explinations for that position are different. I really try hard to understand what they are telling me, and I try like hell to poke holes in the explinations they give, to see if they hold water.

Maybe you should take a minute and figure out how to calculate battery times and current flows for yourself. I am learning, and the more I learn, the more I like.

If you are a fan of smaller aircraft ( under 20oz) then you really ought to give some consideration to Li batteries. They are not for every application. But in some motor/gear/winload cobinations they are fabulous. Better than anything else. And I have a few tricks up my sleeve for later this month, now that I have had a little bit of time to get my feet wet. As amazing as it may seem to those of you who have read some of my more, how do i put it..., fictional writings?

I started a real dummy. But you just wait. I spent the evening discussing a couple cool ideas with a friend, and like I said... gimme a bit, I have something cool to show you.

fair winds, following seas

[This message has been edited by watersharer (edited 08-06-2001).]