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-   -   Not enough nose weight. (https://www.rcuniverse.com/forum/s-p-d-aircraft-coroplast-design-178/11628476-not-enough-nose-weight.html)

ron ward 04-10-2016 07:59 AM

Not enough nose weight.
 
has anyone that built a "Spadet", have to add nose weight to get the cg on the spar, where te instructions say it should be ?.
I have to add a d-cell battery's weight to balance it out with the rx battery pack as far forward as I put get it. !. I thought that was allot of weight to have to add !.

jlguru 04-10-2016 03:06 PM

Perhaps an OS 46 instead of a Super Tiger 40 would help with that? :cool:

Edit: or, perhaps not I just looked up their weights at Tower Hobbies and they are nearly identical.

Live long, and prosper
Jerry

ron ward 04-11-2016 04:22 AM

yah, there can't be much difference between a .40 and .46 weight-wise. I just wondered, because there's no mention of adding weight anywhere in the build article, except, "establish CG". which I guess could suggest that weight might be needed. I do understand that these plans are written with the assumption that those who use them, are reasonably familiar with what is needed to build a plane. to be honest, I was kind of surprised it needs nose weight....... this is one of only about 3 planes I ever built that was tail heavy.

jlguru 04-11-2016 05:37 AM

I've never built the Spadette .... however, I usually build a fuselage including all attached equipment. Then build the wing with all attached equipment. Then I tie the wing to to fuselage with string and move it back and forth to find a position where the plane balances properly. That becomes the wing attachment position. Is it possible to move the wing back a bit?

Live long, and prosper
Jerry

ron ward 04-11-2016 05:12 PM

well, I suppose you could, but a new fuse would have to be built after finding where it balances. wing seat has some airfoil in it, as the wing isn't dead flat on the bottom, so trying to use it once moved, would obviously result in bad incidence. plans call for flat bottom wing and a flat wing seat, but my wing ended up with some airfoil on the bottom.
you're right, though,..... moving the wing back and forth until you find the right balance point would be the way to go,...I never thought of that when building, because there was no reason to think the CG wouldn't be like what was built in the article, and as I mentioned, no mention of needing weight to establish CG.....I know,....rooky mistake from a non-rookie builder......should never assume the Cg will be the same from plane to plane,.... even with the same design.
oh well, i'll live with it and add some lead to the nose.

jlguru 04-11-2016 08:07 PM

I think adding weight and forging ahead is what I'd do. If I remember correctly, you've added a foot to the wing span over the plan (?) so it should carry some extra weight easily. I think you'll be pleasantly surprised. IMHO getting the CG right is more important for success than obsessing over weight. My planes always seem to come out heavy and they fly well. One is a 60 inch BUHOR powered by an OS 65 LA that I call the "Gooney Bird" because it looks like a B-29 with a full load of bombs trying to lift off from Okinawa. But once in the air and "on the wing" it is a pleasure to fly.

Any way to move the motor forward on the motor mount?

You are balancing on the wing spar .... right? .

You could shim the wing at either the leading edge or trailing edge to get an appropriate angle-of-attack (I frequently do that-).

Just throwing out ideas and I'm out of new ones ...hope I'm helping ,,, it's hard doing this blind.

Live long, and prosper
Jerry

ron ward 04-12-2016 10:10 AM

I took another look and moved the wing back an inch to get balanced. yes, I am balancing on the spar. It looks a little short coupled in the tail, but I've noticed that a lot of the SPADs I see look that way. the wing seat issue wasn't as bad as I had first thought. It only took another layer of weather strip foam on the front 1/3 of the wing seat to get the right incidence back after moving it. I simply made a small block of balsa that was epoxied to the front of the wing seat for the leading edge to bump up against. I shaped it to follow the "windshield" of the cabane and it looks just fine ! I like that much better than adding weight, as you say, I realize balance is more important than worrying about a little extra weight, but If possible, getting the balance right while not having to add weight, will always be better. i'd rather experiment with wing location than add weight, if at all possible.

jlguru 04-12-2016 02:17 PM

Good news ... way to go! Keep me posted on how it goes. Looking forward to a successful maiden flight.

Live long, and prosper
Jerry

Clean 04-18-2016 04:32 AM

There are variances in the weight of the plastic, in the weight of the PVC formers and in the weight of the glue. Any weight on the tail is multiple times more moment arm then that in the nose. The Spadet has a bunch of wing, I'd have added some nose weight to see if we could balance it out.

It's a little observed fact that ARFS that show up at trainer night never balance right. the kit says put it together and check the cg, maybe. Not unusual to be tail heavy. New kid on the line in China somewhere using too much "glue". When building the PVC ships like a Daggar or Dart I leave the nose long and after mounting the wing I slide the motor,tank,firewall and servo attached together in the nose and check balance then shorten the nose till it's right. Little late now for you on the spadet but like mentioned, there's a lot of wing there that can absorb 6 ounces with no real problem.

ron ward 04-18-2016 05:03 AM

I too, prefer to move the nose moment to achieve balance if I can. I assumed this build would come out pretty much like the plans read, so I didn't leave any extra length on the nose to move things around.......never fails,....that's what you get when you "assume" !.

richard dee 04-21-2016 03:33 PM

Much larger engine.You can never have too much power.If it wont go straight up it's not enough

Clean 04-25-2016 08:35 AM

^+10000

jlguru 04-25-2016 03:25 PM

Ron Ward: Have you flown this plane yet? Curious minds would like to know.

Live long, and prosper
Jerry

ron ward 04-27-2016 05:11 AM

no I haven't, I just got done making a set of styrofoam floats for it and haven't been up to the cottage where I will fly it yet. it's got wheels on it right now. as said, I haven't flown in 40 some years, so i'm going to wait until I join the local club, an get some coaching.

jlguru 04-27-2016 05:48 AM


Originally Posted by ron ward (Post 12206993)
no I haven't, I just got done making a set of styrofoam floats for it and haven't been up to the cottage where I will fly it yet. it's got wheels on it right now. as said, I haven't flown in 40 some years, so i'm going to wait until I join the local club, an get some coaching.

OK ... I'll wait patiently.

Live long, and prosper
Jerry

combatpigg 06-06-2016 04:23 PM

How hard is it to reposition a wing with any of these SPADS...?


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