Jump to content
Sign in to follow this  
headhunter23

Anyone see a big plane where prop is right at the back?

Recommended Posts

pushed the wrong button? Good idea on rubber band, got lotsa those. the Acetone is working but it's also eroding the protective layer on the stator. Can't win.

Share this post


Link to post
Share on other sites

Just brush a very thinned coat of epoxy on the stator. Use that left over acetone to thin it... A HI Temp epoxy would be nice if you can find some. Probably at an auto parts store.

Edited by W3FJW-Ron

Share this post


Link to post
Share on other sites

Ok, apparently I need 24 guage to replace the 10X34 guage(sorry not 5 but 10). Umm......... magnets are positioned, nsnsnsnsns etc. Finally got all the wires out, will start tearing the good motor apart, will pickup wire tomorrow. Doing wye style, so really I can reduce turns to roughly 5 to be equvilant rpm correct? But will try to fit more turns to reduce speed of motor.

And when I wire, needs to be clockwise, counter, clock, counter etc. correct?

Ummm any other tips?

Share this post


Link to post
Share on other sites

Well got her to run, original was 26-27 amps on 8x4 prop. Changed motor to 8 winds wye(is equvailant to 13.6 turns on original delta) which reduced rpm and amp draw to 14amps, so I would beable to put on a larger prop. Downside is wrapping so many poles 12 it's surprisingly hard to keep count, on top of that I have this feeling I messed one of the poles. Anyways after running for a while it burned out yet another coil, so could be esc now but also possibility of my wiring. So going to rewire again and do it better slower etc.

Still good learning experience. :)

Edited by headhunter23

Share this post


Link to post
Share on other sites

Ok here's good news, didn't have to rewind the entire thing. I know the omh's on the coil that died did flutter once or twice when I was testing, didn't think anything of it because I thought could see where it was touching and was putting heat shrink over that area, on top of that not sure if the coil was indeed wound the wrong way on one coil as getting it apart was a little more difficult than I woulda expected and just pulled her apart. Anyways long story short, checked other two set, wound the third. Put back together and works. Now under full throttle it pulls 7 amps. So I'm thinking either A. the third coil was wound the wrong way on a coil and pulling more amps fighting the magnets or B. there was a very slight connection to the stator. Anyways ran full throttle for 5 min, no problems, consistent 7 amps, no rpm loss etc. You can hear the coils themselves vibrating so will get epoxy on them to get them solid although I don't think there would be an issue if I didn't.

Yah! :)

Going to rc shop now to see what biggest prop is I can spin.

Share this post


Link to post
Share on other sites

<_< Crappy, I didn't try the 16" although I could have, at 15X6 I'm pulling 26amps, at 14x8 24amps. Geeeeeeeeeeeez... I would like to pull 35amps. Sooooooo will rewind motor to 7 winds, see if that boosts the speed enough to pull around 35 amps. Anyone tell me this is a bad idea within half an hour o this post. Taking dag for a walk.

Ivan.

Edited by headhunter23

Share this post


Link to post
Share on other sites

Had received motors friday, finished everything sunday. Took out. Design is almost totally dependent on rudders. Crashed three times, third time I destroyed it out of sheer frustration. Was still too tail heavy even though cg was 22% with heavier motors on the front.

Ivan.

Share this post


Link to post
Share on other sites

If it's any consolation, one of the pilots died while testing the first flying wing........ Fortunatly the second managed to bail out safely. My suggestion would be to use a swept back wing. Flying "planks" are notorious for being unstable in the pitch axis.

Share this post


Link to post
Share on other sites

I think I'm going to stick with zagi's... or atleast do some more testing with them(so far one 4ft, 5ft, 9ft).

I made a 9ft (was 10.5ft but cut it, just cause it was so fricken big) zagi outta blue core. Flies, but A. too big, need another person to throw it, and B. too big.

I'm thinking of trying to setup some hot wire and make two halfs of a zagi outta 2" blue core or maybe glue 2 two inch pieces and make a four inch thick wing that's 7ft long or just a smidgen more(I think I can make 78" fit in bed o truck).

I think I've been through over 9-10 airplane designs now, it's interesting how difficult it is to get what I would call good professional video. With also the restriction that it be foam, not that I'm flying over people but certainly people would be near by and it's always good to be prepared. Not to mention repairs are simple and quick.

Search continues...

btw I do have faith in eddies design but I think ron's right in that it should be more of a foil design...

Share this post


Link to post
Share on other sites

Why not try 3mm Depron wing skins with 6mm Depron ribs... Nice & light and easy to make. Put some carbon tow on the leading edge for additional strength & impact resistance...

Share this post


Link to post
Share on other sites

clever... not sure I have enough, but darn that might even be more crash resistent than blue core and epp. Been doing measurments, I can make an 84" just barely fit in the back of the truck. Actually in photoshop it looks like 86" is my limit. ;)

Thanks for the idea, hadn't come across it in my searches yet.

Ivan.

Share this post


Link to post
Share on other sites

Ron, had looked around for depron, it's wierd we must not have it here so much in Kan a da, eh? As neither rc shop carried it and I wasn't willing to drive an hour and a bit to toronto to see if some of the stores had it there, so went with coroplast. Tried 4mm coroplast(4x8), decided to make 84" flying wing, wished I had taken photos to show you guys. Apparently when you make it out of one 8x4 sheet making both the top and bottom you can only make it 82" wide(this size weighs in 970g, for further testing, I'm going to get 2mm corroplast and reduce blue core that holds camera further). I compensated by increasing the foil height. Apparently I had gone too far as when I used spray foam for the centre blue core it increased the height of the foil even further than expected by an extra 1" taller(compared to zagnuts scaled up design). darn that is strong stuff for expanding, didn't think I put that much in, nor where it was stuck would it affect the foil so much. Anyways decided to try it, plane lifts off of pavement no problems, but can't do grass as needed. But it flys really really slow and needs a lot more power than I had used(too much drag). I think under full power of 2000rpm/v 60amps, spinning 8x4 prop, it's walking speed with 2.9kg all up weight. So changes that would be neccessary for this new plane would be to reduce the foil and change the motor. I have some 800rpm/kv motors but would mean taking off all the wheels and such and lengthening the height so the 15" prop can spin. Which was something I was trying to avoid, but at this weight it seems it's neccessary. Going to put this on back burner for a couple days to think about it.

In the mean time, due to yet another failed design, decided to give the old cularis wings a go, on a design I had seen a while ago. Not sure if any of you have seen the whispershots.com airplane or spoken to "power" on rcgroups.com(if your interested do a search on him there and check out all posts started by him and look around at ultra beast or something like that) but the design works, although I think it would be better with ailerons, as right now it's designed similar to easystar in terms of funtion and is much more affected by wind without ailerons. Very simple, light weight... am trying to lighten up as much as possible for this new plane. He has a really nice design for the wheels. He seems to make 4.5" wheels out of epp or some sort of hard black foam from computer cases that are insanely light and able to handle good load and don't require springs or heavy duty landing gears to take hits. The wheels are 4-8g depending on how they're made. Axel is carbon fibre rod... perhaps the lightest landing set I have seen thus far. The wheels and landing gear for my giant wing are over 200g, these include 3x3.5" "light wheels"(from hobby store) which seem to weigh in around 40g a piece plus all the metal for the shafts and wood to apply to body of plane. So for those of you looking to lighten up landing set, this guy has got a great idea.

Almost done the plane, tail section is just about done just need to mount servo and control surface stuff... main body needs a little more work in terms of wiring(just need to add y split for ailerons) and finally need to figure where exactly the wings need to attach. I'm sure I can get help from rcgroups.com about this but there's plenty o smart guys here... so quick question about wing placement. Do I determine where the wings go by completing everything then look for cg point on body where everything is balanced then cut out so wing cg point is in the same spot? Or is there much more math to figure out first(eiiiyiyi). Helps appreciated ;) (btw there is plenty of room to plug wings to fuse, it's an ugly design...

Will have some photos up soon, at this point till I get a response I'm going to continue completing the body and tail stuff...

Ivan.

Share this post


Link to post
Share on other sites

A good start Ivan, as you said would be to find the balance point of the fuse and then cut out for the wing matching the balance point to the wing COG. The fuse will have an aerodynamic bearing on the overall CG but it should be close and be able to balanced out by equipment placement.

Edited by W3FJW-Ron

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...