Not enough nose weight.
#1
Senior Member
Thread Starter
Join Date: Dec 2010
Location: merrill, WI
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts

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 !.
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 !.
#2

Join Date: Jan 2002
Location: Winnemucca,
NV
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts

Perhaps an OS 46 instead of a Super Tiger 40 would help with that? 
Edit: or, perhaps not I just looked up their weights at Tower Hobbies and they are nearly identical.
Live long, and prosper
Jerry

Edit: or, perhaps not I just looked up their weights at Tower Hobbies and they are nearly identical.
Live long, and prosper
Jerry
Last edited by jlguru; 04-10-2016 at 06:33 PM.
#3
Senior Member
Thread Starter
Join Date: Dec 2010
Location: merrill, WI
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts

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.
#4

Join Date: Jan 2002
Location: Winnemucca,
NV
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts

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
Live long, and prosper
Jerry
#5
Senior Member
Thread Starter
Join Date: Dec 2010
Location: merrill, WI
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts

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.
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.
#6

Join Date: Jan 2002
Location: Winnemucca,
NV
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts

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
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
Last edited by jlguru; 04-11-2016 at 08:16 PM.
#7
Senior Member
Thread Starter
Join Date: Dec 2010
Location: merrill, WI
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts

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.
#9

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.
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.
#10
Senior Member
Thread Starter
Join Date: Dec 2010
Location: merrill, WI
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts

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" !.
#14
Senior Member
Thread Starter
Join Date: Dec 2010
Location: merrill, WI
Posts: 210
Likes: 0
Received 0 Likes
on
0 Posts

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.
#15

Join Date: Jan 2002
Location: Winnemucca,
NV
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts

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.
Live long, and prosper
Jerry