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SPA3D wing issues ... help!

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SPA3D wing issues ... help!

Old 11-26-2003, 04:53 PM
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Default SPA3D wing issues ... help!

Hello All

Just finished my SPA3D built as per Tatoo's plans. Below is my list of equipment...

OS MAX 50 SX
APC 12.25x3.75 Prop
All Servos are Hitec 425BB

On its maiden flight, I lifted off into about a 10 ~ 12 mph head wind at about a 20 degree climb. I was at half throttle and she was surprisingly in trim. I began a shallow left bank turn and she began to pick up a little speed due to tail wind. I applied right alerion to level out and she maintained a left bank. So much so that I had to apply negative rudder to knife edge a bit to keep her outta the trees. I applied FULL right alerion and she STILL kept banking left. In a desperate move to keep her up, I applied full LEFT stick and she rolled on over and leveled out.

I knew I had an issue so I called for an emergency landing and began another left bank turn to land. As soon as the nose was into the wind, the whole wing fluttered big time. I choped the throttle and the "butter fly from hell" stopped fluttering and I landed safely.

A post flight check showed everything to be fine. I opted for a second flight after I put a ton of right alerion trim in. On lift off, she rolled right, and did the same thing. I slowed her down, rolled her over and leveled out. Also, every time I would turn into the wind the entire wing would flutter. I had the sky to myself so did some in flight testing. Anything above 15 ~ 20 mph wind speed induced harsh flutter. I was having to fly at about 1/8 throttle just to maintain lift with no flutter.

It dawned on me later that what was causing my roll issue was not that the wing was out of trim, but in a turn, wind was traveling more over the top of the downside wing causing it to couple bad. What it comes down to is my wing is WAY unstable at anything above flight speed. The leading edges are weak enough to induce a coupling roll and massive flutter that can visually be seen starting on the leading edge.

Any ideas out there on how to take care of this issue? Anyone out there had the same problem? As I said before, the plane is built to Tatoo's specs. Any help or suggestions would be appreciated. This is my first SPAD. I know other pilots are flying the SPA3D with the 50 SX so I don't think I am over powered.

Rick
Old 11-26-2003, 05:54 PM
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Default RE: SPA3D wing issues ... help!

slow down! Its not made for speed. Keep the nose up, and use the throttle to maintain altitude. Full throttle is only used for pulling vertical, nothing else. 3d means done below the stall speed of the wing.
Old 11-26-2003, 06:28 PM
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Default RE: SPA3D wing issues ... help!

ORIGINAL: ChrisSpad

slow down! Its not made for speed. Keep the nose up, and use the throttle to maintain altitude. Full throttle is only used for pulling vertical, nothing else. 3d means done below the stall speed of the wing.
Slower???? I never got it above half throtle and that was on takeoff. I flew ... errrr ... attemted to fly at 1/4 trhotle ans still got flutter and coupling. I have seen SPA3D fly faster than mine with no flutter issues. How am I supposed to do manuvers like a Wall, Blender, Parachute, etc. without taking it above stall speed?

Rick
Old 11-26-2003, 06:45 PM
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Default RE: SPA3D wing issues ... help!

did you put the music wire in the trailing edge like the instructions call for?
Old 11-26-2003, 06:55 PM
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Default RE: SPA3D wing issues ... help!

ORIGINAL: ChrisSpad

did you put the music wire in the trailing edge like the instructions call for?
Yuppers ... Built to Tatoo's specs off spadtothebone.com ... forgot to metion that the second flight left me with a bent fuse and cracked motor mount ... cracked where the throtle servo goes.

Rick
Old 11-26-2003, 07:51 PM
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Default RE: SPA3D wing issues ... help!

It's posts like these that always have me scratching my head, because I'll be the first to admit that I don't have a clue why you're having problems. The plane you saw in the plans and built your's too, was flown hard with 100's of flights, more doinks than I can count, thrashed, bashed, used and abused...it basically taught me 3D. I'll bet it went through $100 worth of props. It never fluttered. Even on it's last day at the field, and looking like a rag doll...it was still flying like the day it was built. It did have some twist issues between the wing and the fuselage at full power...and I tried to make it clear in the instructions to use higher throttle with caution. This issue was solved with the Spa3dt by running the forward MW through the fuselage. Also on the Spa3dt I elected to run a full 36" piece of MW through the trailing edge to get better aileron response. I'm currently carrying on my thrashing habbits with my Spa3dt, and she takes everything I can give it at any throttle setting, and so far it's solid as a rock. You said that you've seen other Spa3d's flying with the same engine as yours with no problems. Have you investigated their airplane and compared it with your's? Without seeing your plane I can only make guesses. All coro is not created equal. I'v had some thick and tough, and I've seen it thin and whimpy. Did you score the LE flutes or actually cut through one side? I've tried cutting one side of the flutes once, and the LE was too flimsy and distorted on higher speed flight. Are your linkages solid and slop free? Are your aileron pushrods flexing? As for the engine mount, was it Wal-Mart American Chef brand? I still have yet to bust one...and believe me, I've tried. As for the Fuselage bending...you'll notice I went to square tubing with the Spa3dt...it took one heck of a summer to do it, but that's what finally got me to build a new plane. My recomendation would be to go to a full length trailing edge MW, and move the forward MW back 1" and run it through the fuselage...this will make the wing to fuselage much more solid.
Old 11-26-2003, 08:13 PM
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Default RE: SPA3D wing issues ... help!

Do you have the wire spreaders in the wingtips?
Old 11-26-2003, 08:53 PM
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Default RE: SPA3D wing issues ... help!

ORIGINAL: Tattoo

It's posts like these that always have me scratching my head, because I'll be the first to admit that I don't have a clue why you're having problems. The plane you saw in the plans and built your's too, was flown hard with 100's of flights, more doinks than I can count, thrashed, bashed, used and abused...it basically taught me 3D. I'll bet it went through $100 worth of props. It never fluttered. Even on it's last day at the field, and looking like a rag doll...it was still flying like the day it was built. It did have some twist issues between the wing and the fuselage at full power...and I tried to make it clear in the instructions to use higher throttle with caution. This issue was solved with the Spa3dt by running the forward MW through the fuselage. Also on the Spa3dt I elected to run a full 36" piece of MW through the trailing edge to get better aileron response. I'm currently carrying on my thrashing habbits with my Spa3dt, and she takes everything I can give it at any throttle setting, and so far it's solid as a rock. You said that you've seen other Spa3d's flying with the same engine as yours with no problems. Have you investigated their airplane and compared it with your's? Without seeing your plane I can only make guesses. All coro is not created equal. I'v had some thick and tough, and I've seen it thin and whimpy. Did you score the LE flutes or actually cut through one side? I've tried cutting one side of the flutes once, and the LE was too flimsy and distorted on higher speed flight. Are your linkages solid and slop free? Are your aileron pushrods flexing? As for the engine mount, was it Wal-Mart American Chef brand? I still have yet to bust one...and believe me, I've tried. As for the Fuselage
bending...you'll notice I went to square tubing with the Spa3dt...it took one heck of a summer to do it, but that's what finally got me to build a new plane. My recomendation would be to go to a full length trailing edge MW, and move the forward MW back 1" and run it through the fuselage...this will make the wing to fuselage much more solid.
Thanx Tatoo ... I will give the one piece music wire a try and go through the fuse. My motor mount was the "poly" type American Chef brand bought at Wal-Mart. I think I might try to do a new motor mount design like you did on the SPAD3DT. All links are solid with zero slop. Brand new servos with heli style ball links. 4-40 push rods with no flex. I bought the coroplast here in Dallas and it "might" be a bit on the weak side. I will have to compare my spad to others at the field.

Thanxs Again
Rick
Old 11-26-2003, 08:54 PM
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Default RE: SPA3D wing issues ... help!

ORIGINAL: RC_Fanatic

Do you have the wire spreaders in the wingtips?
Yuppers ... made out of a coat hanger just like the specs said.

Rick
Old 11-27-2003, 06:20 PM
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Default RE: SPA3D wing issues ... help!

I may be wrong but it could be tail heavy.
David
Old 11-27-2003, 09:35 PM
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Default RE: SPA3D wing issues ... help!

More MW. Like TATTOO said one 36" peice in the last flute on the trailing edge. It sounds like you are getting tons of flex in the wing. On my SPA3D I have three peices of MW in the wing. One at the LE going through the fuse, one mid cord going through the fuse (both are 18" ) and one full span at the TE. I also have two bamboo scewers shoved into the flute at each aileron LE. I usually fly mine just above stall, but after reading your post I was curious and flew mine today for a while at higher speeds. Other than the controls being slightly desencitised, I noticed no adverse affects. It sounds like your wing is really flimsy probably due to the coro. I have a sheet of yellow sold to me as 4mm that is more like 3mm or less. It is tons more flimsy than my red coro (visibly thicker). I think you should just reinforce the wing with more MW and try again. A few ounces wont matter with your powerplant. You are almost there.

WILLIAM
Old 11-27-2003, 11:14 PM
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Default RE: SPA3D wing issues ... help!

Try a different colour of coro, the various colours actually have different stiffness
Old 11-30-2003, 11:04 AM
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Default RE: SPA3D wing issues ... help!

Heads_up,

Go buy yourself a bag of bamboo skewers, and go crazy.

They are very light. Just stuff them in anywhere you think you need 'em.

You can always 'unstuff' them if you want.

Wal-mart stocks them right by the cutting boards, buy the larger diameter
if they have them.

John
Old 11-30-2003, 11:16 PM
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Default RE: SPA3D wing issues ... help!

Hell if Tattoo can't figure it out, what the heck to I know.

But I know intially mine was a handful, until I got the CG forward a little bit (in other words, less tail heavy). These things seem to be VERY VERY CG sensitive, and I did have one of my wings get pretty sloppy in rolls. I crashed it before I REALLY figured out why, but one thing I have definately noticed is the following:

Because nearly all of the lift in straight and level flight is generated through angle of attack, its almost always in some amount of nose up flight. This means that the aileron deflection ABOVE the wing is in turbulance, and the aileron deflected BELOW the wing is in the main thrust of the air, generating more extra lift. On one of my wings, I had a very stiff set of aileron joints. I didnt worry too much about it, and had "sloppy bad aileron" problem. I did some hard work at 1 0 feet and full throttle trying to figure it out.

In the end, I loosened those ailerons WAY WAY up, and also made a conscious effort of giving a little down elevator before doing a fast roll. Both work a charm.

Note: I have found that ailerons are almost ALWAYS stiffer going down than up (even with NO binding) assuming the cut is made on the bottom. Something about the grain of my Coro I guess.
Old 01-12-2004, 06:41 PM
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Default RE: SPA3D wing issues ... help!

Howdy Guys

Been in the hospital since the week before Thanksgiving so ... sorry it looked like I dropped the post.

My SPA3D is done in yellow coro and it seems to be weaker than the darker colors. Gonna stiffen the wing up wie MW and/or scewers. Thanx for the info.

Rick
Old 01-12-2004, 07:01 PM
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Default RE: SPA3D wing issues ... help!

My yellow coro is thinner than my red. It's actually more like 3mm. The first spa3d I built had a yellow wing and never flew right. When I use the thicker red, they always fly great.

Check your yellow and if it is thinner, da as suggested and start bracing with bamboo.

William
Old 01-12-2004, 07:40 PM
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Default RE: SPA3D wing issues ... help!

Did you forget the screw in the back on the wing, by the aileron, by chance? It sounds to me like the wind is blowing the wing axial to the fuse and I can imagine that happening without that screw back there. Maybe double check all the little things like that...maybe you missed something small like that by oversight.
Old 01-16-2004, 11:21 AM
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Default RE: SPA3D wing issues ... help!

A few tips for SPAD3Ds, make sure ailerons are pointing upwards and not level, I like to set mine even with the top of the fuse, makes it much more stable. To help prevent flutter on rudder, rip some small pieces of wood to fit snugly into the flutes where the vertical fin screws to the fuse, then screw the fin on through this area and back up your screws with wood or plastic. This will greatly reduce risk of flutter in the rudder.
Old 01-16-2004, 09:55 PM
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Default RE: SPA3D wing issues ... help!

Really? I have never has that problem and i have light blue red and yellow [sm=stupid.gif][sm=surprised.gif]
ORIGINAL: MalaysianFlyer

Try a different colour of coro, the various colours actually have different stiffness
Old 01-17-2004, 12:03 AM
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Default RE: SPA3D wing issues ... help!

Heads_Up,

Welcome back! Sorry to hear about your stay in the hospital; hope everything's OK!

Let us know if the MW fixes the problem; inquiring minds want to know...

Blue skies,
DL
Old 01-19-2004, 03:51 PM
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Default RE: SPA3D wing issues ... help!

Heads_Up, What field do you fly at?
Old 01-21-2004, 01:27 PM
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Default RE: SPA3D wing issues ... help!

ORIGINAL: MasterSmasher

Heads_Up, What field do you fly at?
Metro East RC Club in Mesquite. We fly accross from Samuell Farms at Hwy 80 and Beltline Rd..

Rick

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