Next Plane?

[19000rpm]

Designing and building a plane is a great step. You'll learn a lot.

[akent]

One thing you probably will need to get is some carbon fiber. 3mm square or round tubes and some flat carbon works well. Larger wings might need 5mm tubes.
All of these foamies benefit with some carbon, in the wing at least.
Hobby King has a pretty good price on it, but the shipping is high. I don't know who sells it locally for a good price. I just bought a bunch of it a while back from HK.

Yep, building planes is a ton of fun!

If you want to wade through a lot of designs and have a printer, check out RC Groups (www.rcgroups.com) in the foamie section. There are dozens of designs for planes and jets. Most are depron or blue core (available at Home Depot) that you could probably make the dollar tree foam work with. There are some EPP designs, too.

EPP will by far be the most durable, as 19k mentioned. But it's not as rigid and needs more carbon fiber stiffening.

Have fun!
Kent

[r/c basher]

Building foamies sure has taught me alot.

I went to my lhs a while back and they had some carbon fiber but it was really expensive, I dont remember the price but it was really high and the rods didn't look like the best quality. I just checked out Hobbyking there about a 4th of the price of carbon fiber from towerhobbies where I get most of my hardware.

I might give EPP a try after I mess around with dollar tree foam. On the dollar tree foam if you remove the paper backing the foam is really flexible to much for my liking. I suppose with some carbon fiber rods it would be stiff enough.

[r/c basher]

So Im in the process of building this jet out of dollar tree foam and I got it all built except the electronics installed, but I was wondering if it needs an airfoil? My Extra 300 doesnt have an airfoil. But I was looking at alot of plans on Rcgroups and alot of them had an airfoil. I was looking at different airfoils and the KF airfoil looks simple.

I have no idea if its going to fly or not but we'll see in a couple days, if not a couple hours.

Heres a picture of the jet so far-

Attachments:

[r/c basher]

Well I wont be flying the foamie or anything else for a while . My Dx6i roller wheel just broke on me. Pushed it down to change to a new model to start programming for the jet and it broke. Took it apart and the roller wheel is a piece of sh!t design. One little tiny plastic tab holds the roller in. Been doing some research and a lot of other people have had the same problem.

I basicly have 4 options-
1. Send my Dx6i back to horizon and wait 2 weeks. Researched it and Horizon doesnt just simply ship people tx parts, you have to send it in.
2. Buy a cnc machined aluminum one for $20.
3. DIY the broken roller switch using an allen wrench.
4. Say F#$@ horizon and buy a Futaba, Hitec, or Airtronics. Something with better quality and better receivers.

Im thinking option 3. Im going to try using an allen wrench and fix the roller myself. If this doesnt work Ill spend the $20 for a cnc machined one. F sending it back to Horizon and waiting 2 weeks to get it back with the same old sh!tty plastic roller, thats going to break again.

[r/c basher]

Ok rant over, the dx6i is back in business, I was able to fix the thumb wheel by using an allen wrench, heres what I did- www.helifreak.com/showthread.php?p=900897#post900897 .

One thing that I did different was I didnt CA the allen wrench in, when I drilled the hole I made it a little smaller and I was able to press fit it in. I saved myself $20 or a 2 week wait. Its almost good as new, except that sometimes I have to push the roller twice to get it to read.


And just a few minutes ago I maiden my dollar tree pusher jet. It failed miserably, it was way to tail heavy, even after I had the battery moved all the way forward. I tried multiple times but it would just flip over and crash. I should of known better that it was way to tail heavy in the beginning. I feel stupid. Now Im rethinking this design, I might try the motor in the front or mid section and see what it does. It survived about 10 crashes tonight though. I think Im done though building scratchbuilt planes that are done by plans made by me.

[akent]

Good job on fixing your DX6i!

Here's a tidbit for when you scratchbuild stuff.
The CG is 'normall' 1/3 of the wing cord back from the leading edge, near the fuselage.

That will get you in the ballpark 95% of the time, unless it's a really strange design.

You'll get it, Basher!
Kent

[r/c basher]

Jun 28, 2011 22:56:00 GMT -6 akent said:

Good job on fixing your DX6i!

Here's a tidbit for when you scratchbuild stuff.
The CG is 'normall' 1/3 of the wing cord back from the leading edge, near the fuselage.

That will get you in the ballpark 95% of the time, unless it's a really strange design.

You'll get it, Basher!
Kent

Thanks Kent, the CG was around 2/3 back of the wing, so that probably was my problem. I might try a bigger battery, thats the only way I really can balance it out, it beats adding dead weight. If I cant get the CG right Ill move the motor to the front, and try.

Now for airfoils, I have been doing alot of research on the KF airfoil and one of these times Ill try one. But I was wondering if an airfoil is necessary for these flat foamies? I know an airfoil will create more lift and probably fly better.

Sorry about my little rant yesterday about my dx6i, I just thought it was SOL.

[akent]

Yeah, tail heavy planes can be next to impossible to fly!

Sometimes the KF airfoil can make the plane very 'pitchy' or touchy on the sticks with the extra lift. I built a foamie flat that flew well and after I added the KF airfoil it was so 'pitchy' I could hardly fly it.
Other's I built fly better with the KF airfoil.
I have no idea how to tell what works and what doesn't, unfortunately.

I think if you build it flat and it doesn't fly well, then you could try the airfoil, if it is sluggish.
Kent

[r/c basher]

Jun 29, 2011 8:17:49 GMT -6 akent said:

Yeah, tail heavy planes can be next to impossible to fly!

Sometimes the KF airfoil can make the plane very 'pitchy' or touchy on the sticks with the extra lift. I built a foamie flat that flew well and after I added the KF airfoil it was so 'pitchy' I could hardly fly it.
Other's I built fly better with the KF airfoil.
I have no idea how to tell what works and what doesn't, unfortunately.

I think if you build it flat and it doesn't fly well, then you could try the airfoil, if it is sluggish.
Kent

Thanks again Kent. Hopefully Ill be able to get this up in the air and make it fly. One thing that I dont think Ill do again is paint the dollar tree foam, I painted the Extra and then the paper started coming off some, I didnt paint this jet and I dont think Im going to.

[19000rpm]

Nice job fixing th Tx.

The CG thing can be tricky. Like kent said a conventional wing it's usually in the first 1/3 of the Chord. I had a guy with a big Storch ask me about his CG the other day. I pointed to the exact spot we found in his instructions later on. Once you get into delta wings, sweptback wngs and designs with lifting bodies then it becomes less easy.

[r/c basher]

Jun 29, 2011 14:16:35 GMT -6 19000rpm said:

Nice job fixing th Tx.

The CG thing can be tricky. Like kent said a conventional wing it's usually in the first 1/3 of the Chord. I had a guy with a big Storch ask me about his CG the other day. I pointed to the exact spot we found in his instructions later on. Once you get into delta wings, sweptback wngs and designs with lifting bodies then it becomes less easy.

Thanks 19k, I tried a 1300 mah battery instead of the 800 that I was going to use and mounted it as far forward as I could and it was still tail heavy. Then I took a 9 volt battery and strapped that down infront and it was getting better, but still flips over. Now Im going to go out and try a 2200 mah battery which IMO is way too heavy but its literally my last resort to try.

If that doesn't work I'm taking the motor out and redoing the whole thing and mounting it on the front. I think I like the prop on the front better anyway.

[r/c basher]

Well just tried her with the 2200 mah battery and it still was a no go. The flight did last longer though. I had the battery as far forward as I could. It still flipped eventually instead of flipping instantly it stayed in the air about 2 seconds longer. But now its to heavy to fly anyway, it reminds me of trying to fly a brick. As soon as I launched it, it would go all crazy. One thing about dollar tree foam, its durable I've had 20+ crashes with it and only have a little wrinkled nose and tail fin. Of course it crashed at a lot less speed then it would if it flew.

In a few minutes Im taking the esc, motor and receiver off of it, and modifiying it and have the motor in the front and try. It should be alot easier to get the CG right without having to use such a heavy battery. And it will hang on the prop more in the air, which should give it better flying characteristics because its pulling the plane along instead of pushing.

After the very first attempt at flying this plane, I named it FAIL! in my Dx6i. lol

[r/c basher]

Heck yeah it flies! I cut the nose off and made a motor mount out of wood and hot glued it on, mounted the motor on it. Installed the electronics and took it out for its maiden.

First attempt resulted in a crash because the battery caused the plane to roll, adjusted the trim accordingly for a second attempt and it flew! I needed to adjust the CG a couple times until I got it right. After that it flew great. Its plenty acrobatic, I had my Dx6i expo set to +40% and I was still barely able to move the stick. I didn't try any rolls or loops yet. It flies great at about 1/3 throttle, haven't tried flying any faster. The glide rate is great, better then my Super Cub. With the motor off it just glides forever without any tendency to stall.

If you guys are interested Ill post up the directions for where I made the cuts at on the dollar tree foam. It only took one sheet to build it. Ill try and post up a picture of it some time.

I still can't believe it flew this well for something that I made without any plans or knew for sure what the heck I was doing.

[19000rpm]

Great News. Trial and error is always in the development equation. Congrats for sticking with it.

Show us some more pics.