Too much lift when flying upwind-can I adjust something?

[phupper]

Hi,
I did an E-conversion on a grocery store foamy. It flies great, but when I go up against a breeze it wants to climb dramatically, so much that I had to land on a downwind run.

Is there some adjustment in the CG, or wing-angle, etc. that would lessen this effect?

Thanks!

[Gnascher]

Can you change the angle of incidence on the wing?

[pd1]

Phupper, Can you raise both ailerons a little.
Raising them should give better wind penetration.

Maybe a little more elevator throw might also help.

Paul

[stevecooper]

phupper:: Gnascher"s comment" incidence on the wing? " sounds dead on here, She's flyable so you did something right anyway!!! chunckers are a crapshoot an out of the last case of em I bought ( 6 planes) two were way out, They stack-em stand'in-up so the wings can get warp an cat'ie-wopp'us on you, Stand 15' away from the front an site down her wing-span for cat'ie-wopp'us'ness, you sound like a long-time flyer from your post an I'm prob'ly not tell'in you anything new, just stuff I've forgot to do in the past, How bout some pixs as I'd love to see her, your bub, stevecooper PS I chop the wings a 12'-18' to get the float'ie'ness out of em, pd1 (http://www.wattflyer.com/forums/member.php?u=9552)'s comments were also eye-opening, good post'in my bub!

[phupper]

Here's the thread where I posted pics a few days ago. It has no ailerons.

http://www.wattflyer.com/forums/showthread.php?t=24291

As I understand it, flying into the wind, (or just going faster) produces more lift. But the plane seemed more like it wanted to "point" up, not just "lift". My first thought was more weight in the nose, but that's just a guess, and the CG is at the recommended 2" back.

I'm definately not a "long time flyer", but this is my 3rd foamy E-conversion. I have 3 flights out of like 5 attempts, but today I actually got to land the plane!

When you say "change the angle of incidence, do you mean more or less?

Thanks for your replies!

[stevecooper]

YES!!! NOSE NEEDS WEIGHT( or move batt's forward,) On my last one the 11th fite was the first "Flight" I refused to believe it could be that far forward! now she's my favorate, your comment "point" up, not just "lift". is the telling tail! try 1 1/2" next time, your bub, stevecooper

[oimmuk]

Steve, impressive Fleet ya got there... :D

[stevecooper]

oimmuk:I've got 25 or so for the kids in my youth-club MULLETS MAURODERS an 20 or so for me!! Kids are do'in some chunckers now an should have some fly'in soon( Funky paint jobs!!!) I'll post pixs,They go nose heavy cause they like em fast!!

[pd1]

phupper, A couple of questions.
1. In your other post you said you moved the wing up and gave it more of a curve.
2. Did you maintain the original incidence angle?

3. Is your horizontal stabilizer parallel to the wings lower surface?

You also said it flew OK before.
4. Did the weight change between flights?

5. When you re attached the nose, did you keep the downthrust in?
6. Does the plane pitch up under power?

7. If you toss the plane gently does it glide OK?
8. Does it glide nose down ?
9. Or does it try to pitch up?

Instead of just changing things, maybe we might be able to give better answers if we find the answers to these questions.

I have one and it flies fine with a CG two inches from the leading edge.
That's no guarantee your CG needs will be identical, but it should be in the ball park.

Paul

[CHELLIE]

Here's the thread where I posted pics a few days ago. It has no ailerons.

http://www.wattflyer.com/forums/showthread.php?t=24291

As I understand it, flying into the wind, (or just going faster) produces more lift. But the plane seemed more like it wanted to "point" up, not just "lift". My first thought was more weight in the nose, but that's just a guess, and the CG is at the recommended 2" back.

I'm definately not a "long time flyer", but this is my 3rd foamy E-conversion. I have 3 flights out of like 5 attempts, but today I actually got to land the plane!

When you say "change the angle of incidence, do you mean more or less?

Thanks for your replies!

Hi Phupper :ws: Being a glider to start with, it might have a lot of positive incidence built into the wing or mounting at the fusealage, you may have to adjust it to a neutral incidence or even a little negative incidence, by adding a little spacer to the underside of the main wing at the rear, also you might need to give your motor some down thrust, about 2 or 3 degrees is the norm, I was looking at the wing tips, and was wondering if they might have some up angle built into them, (twisted up) a incidence gauge is a good thing to have when scratch building, take care, Chellie

http://cgi.ebay.com/Robart-R-C-model-aircraft-incidence-meter_W0QQitemZ270165646222QQihZ017QQcategoryZ3405 6QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


http://imagehost.vendio.com/bin/imageserver.x/00000000/bwtool/.mids/DSC00363.JPG (http://imagehost.vendio.com/bin/viewimage.x/00000000/bwtool/DSC00363.JPG?vvid=3549596&allow_mailing_list=1&sp=1)

[MikeMc]

How about flying at the same airspeed as downwind.

Are you saying your stall/landing speed is less than the wind speed? If that's true you can still land with a negative ground speed to some extent.

[phupper]

I moved the wing up, and about 2" forward, the curve is from wingtip to wingtip, done with packing tape pulled tight. (That packing tape does an amazing job of making foam rigid) It still has the original angle of incidence.

Horiz stab is parallel to the wing.

It flew ok before because there was no wind at all. Today there was a moderate breeze.

It does pitch up a bit under power. I will add a little more down angle.

It seems to glide fine with no wind. It flew well downwind too.

It was just hard to control flying into the wind. It wanted to go either up or down, but not level.

Ok I'm gonna add a little weight to the nose and pitch the motor down ever so slightly.

Thanks everyone!

[Insomniac]

Wind (excluding turbulance) doesn't change how a plane flys. Correct me if I'm wrong, but once the plane is up there it is flying the same airspeed going upwind or downwind. Think of it this way. The plane is flying in a 'block' of air. It doesn't know if the ground is moving around under its block of air. If the block of air is moving in a constant direction, the plane doesn't know that either. Flying into the wind should not change the handling characteristics of the plane, only make it APPEAR slower from the ground.

Maybe you are increasing throttle to penetrate through the wind, causing the nose-up problem? Or perhaps there was some turbulence that affected the plane more when it was facing a certain direction? Or maybe the wind was gusting, altering the plane's airspeed?

[jb48]

Right on Insomniac! Once in the air, an airplane (full size or model) relies exclusively to its airspeed and has nothing to do with groundspeed. For example, in my area (and many others) a tenacious mistake is still surviving, a kind of urban legend that says that a beginner, intermediate or even experienced rc pilot has to carefully watch a plane turning downwind because of a so-called tendency to stall. Pure legend. And I proved it to an old rc pilot much more experienced than me in rc flying (on the other way, back in the 80`s I worked as a full size glider instructor). This guy and many others were (and still are sometime) influenced by the way their planes look from the ground, confusing groundspeed and airspeed. In order to make his plane «look» flying at the correct speed, he inconsciously cut a little bit throttle while applying up elevator in turning downwind, the good recipe for a stall while banked! The 75 years old man is still not convinced that his model is flying at the same airspeed, even if its groundspeed varies a lot in windy conditions. Tenacious believing. Alone with him on a windy afternoon, he could not believe seeing my EasyStar and my SuperStar flying for around ten minutes at a deliberatly fixed low throttle position: he was convinced that my planes were overspeeding turning upwind to downwind («you`ll rip a wing») and dangerously flirting with stall when turning downwind to headwind («give throttle, you are about to stall»). I asked him to try the same with his big nitro Fokker but he didn`t, thinking that his plane was «too hot» for that!
Tenacious believing!

[pd1]

Insomniac and jb48 are right, if the plane glides fine in no wind condition do not alter the weight or CG.

Add more down thrust. The glider is light and it has a lot of wing area.
More power means more speed and then more lift.

You need more down thrust to counter the lift.

Another means is Steve Coopers idea, cut the wings smaller, that will give more penetration.

jb48 is 100% correct in the plane doesn't know which way the wind is.
Up wind, down wind, cross wind, it's all the same.

What confuses a lot of people is their perspective.

Standing on the ground and watching a plane fly and fight wind conditions
can give confusing information.

The other thing that can add to the misconception is wind speed.
The wind close to the ground is not always at a constant speed.

Gusty wind conditions can and do cause sudden gains in lift or sink.

Although they're not permanent, a lot of little gusts can give the impression of more lift into the wind.
Especially if you're viewing a lightly loaded airplane from the ground.

Paul

[MikeMc]

And MikeMc since he said it first. Dang, I get no respect. :p

[stevecooper]

phupper (http://www.wattflyer.com/forums/member.php?u=14834)::chop those wings down and cure her "Tip-Stall'in" Fer'ever, Put ailerons on her so you can get out of a tip-stall, Looks like you got enough power to get your leg over the fence in case of a tip-stall but if you can't get the wing down your toast, so chop those hammer-heads (to bad cause they did look sort'a cool) off an reduce the wing load'in a bit an she'll be right as rain , your bub, stevecooper PS. Sponge Mike "And MikeMc since he said it first. Dang, I get no respect. :p " Your post are always good my bub!

[pd1]

And MikeMc since he said it first. Dang, I get no respect. :p

Yep, you did say it first.

Old age is my excuse.
That's my story and I'm sticken to it.

Paul

[phupper]

Thanks for all the great info!

Here's something I noticed. When I first taped the wings they were really stiff. I had streached packing tape across the top and bottom of the wing. This compressed the foam by pulling the wingtips closer together. I noticed that after the first crash some the stiffness was gone from the wings, and the tape had little wrinkles in it. I have retaped the wings so they will be stiff on next flight. Could that have had anything to do with the planes behavior?

Chopping the wings:
I originally wanted this plane to be easy-to-fly, enough so that I don't have to worry too much about losing my wireless video cam, or the plane. So as for chopping down the wings, wouldn't I lose stability? In retrospect, my dihedrals on the wingtips are kinda small. Are they doing anything for stability at that small size?

Air Speed vs Ground Speed:
I don't think I added power when going upwind, but I still get a little nervous in flight, so who knows. I know the plane looked more like a kite than a plane, because of little forward motion (in relation to ground). Now I'm curious. Could too much headwind make a plane appear (from the ground) to be going backwards? In other words, if I have 10 knots of thrust and I'm flying into a 12 knot breeze, wouldn't I still be flying, but appear (from the ground) to be going backwards?

Thanks!

[pd1]

Thanks for all the great info!

Here's something I noticed. When I first taped the wings they were really stiff. I had streached packing tape across the top and bottom of the wing. This compressed the foam by pulling the wingtips closer together. I noticed that after the first crash some the stiffness was gone from the wings, and the tape had little wrinkles in it. I have retaped the wings so they will be stiff on next flight. Could that have had anything to do with the planes behavior?

Chopping the wings:
I originally wanted this plane to be easy-to-fly, enough so that I don't have to worry too much about losing my wireless video cam, or the plane. So as for chopping down the wings, wouldn't I lose stability? In retrospect, my dihedrals on the wingtips are kinda small. Are they doing anything for stability at that small size?

Air Speed vs Ground Speed:
I don't think I added power when going upwind, but I still get a little nervous in flight, so who knows. I know the plane looked more like a kite than a plane, because of little forward motion (in relation to ground). Now I'm curious. Could too much headwind make a plane appear (from the ground) to be going backwards? In other words, if I have 10 knots of thrust and I'm flying into a 12 knot breeze, wouldn't I still be flying, but appear (from the ground) to be going backwards?

Thanks!


phupper, When I first flew my glider I hadn't used any tape on the wings.
It flew fine, once you got over seeing the wings flex wildly after pulling a couple of G's.
The tape was used only to stop the flexing.


Reducing the wing size reduces your wing area.
This increases your wing loading.
Generally speaking a plane with a higher wing loading will fly faster and fly differently.
Wind penetration being better, the faster airplane goes upwind faster.


If the headwind is higher than your flight speed, yes the airplane can appear to fly backwards.
It's not actually, but seeing it from a stationary point on the ground it will look like it's going backwards.

If the wind speed is higher than your flight speed, I wouldn't recommend flying.
At least until you get a little more experience.

Paul

[Sparky Paul]

Your climb "problem" upwind is due to the wind speed reducing the speed over the ground. The plane climbs exactly the same amount in height upwind as it does downwind, but because the head wind reduces the ground speed, it -appears- to be climbing more.
Some of the suggestions to reduce the climb are good, but the easiest method is just reduce power.

[phupper]

I finally got a chance to fly it. My best flight so far, it lasted about 15 minutes, and the plane performed perfectly! I got to make my 2nd controlled landing. (It's nice not having to pick up the pieces)

This plane is really light. I calculated it at 11 ounces, plus the sticks, glue, and tape. The wind tosses it around pretty good.

I had re-taped the wings to make them rigid again. But after a few loops I noticed they were flexing badly. I'm gonna glue some wood stringers into the wings, and chop off the wing tips before the next flight.

Thanks everyone for your suggestions and advice. It turned out great!:)

[Slowjohn]

Howdy phupper,
Glad your making some headway with your plane. I did notice from the photos you posted on the other thread that none of your control rods were supported. You need to support them for a couple of reasons. (1) You'll get better response to your control inputs due to less flex in the control rod. It may not affect your plane while it's not flying or if it's flying slowly but when your putting the sticks in the corners they will flex on you. The faster the plane goes or the more pressure applied to the control surfaces will cause the rods to flex thus causing you to have less control than you think you have.
(2) Supports will take the stress off the control surfaces control horns. The way it is now your likely to over stress the foam where the horns are attached and they'll fail soon.
My first RC plane I built soon became under powered and dull/boring for me to fly so I bought a bigger engine for it. This plane was a 2 ch. and didn't have any throttle control so once it left your hand that was it. Anyway the eng. leaned out and I was in trouble. I couldn't make it turn to the right or climb much. It just kept making a circle to the left and they were getting tighter and tighter until she snapped inverted and went in so hard it broke the engine case when it hit the ground. You can imagine what the rest of it looked like. What we found was that I had not braced the control rods once I put the larger engine into the plane. They were fine for the small eng. but the rods were too flexible for the new power and couldn't make the control surfaces move like they were being told to. It's sickening to watch a plane going down and there's nothing you can do about it :blah: :sad: :{ then to find out that it could have been prevented :mad:.

Good Luck &
Have Fun,
SJ

[phupper]

Thanks. As a matter of fact I did notice that the control rods would bend a little when pushing the horn, and glued small brass tubing pieces to the fuse as control rod guides.

Speaking of stress at high speed, it occurred to me that if the horizontal stab flexes very much, the elevator will be forced out of the neutral position. This would make the plane want to go either up or down. So I'm adding a balsa spar across the trailing edge of the H stab.

I'll post results of the next test flight.

EDIT: Correcting myself. When the H stab flexes, it actually forces the elevator INTO the neutral position.:red:

[John Boy]

Hi Phuffer

In looking at your photos, I believe the wing is a polyhedral (not a dihedral). Since it started as a free flight glider, the polyhedral was intended to help stabilize the plane. Now that you have a movable rudder it will help you turn faster and return to level faster.

Back to your initial question. The plane is clearly a glider. You should fly it as a glider. That is, when you apply power and it picks up speed it will naturally pitch up, uncomfortably up. If you don’t have a Tx that allows slaving down elevator to up throttle you will be fighting the plane all the way up, even pegging the down elevator so it does not loop. Once at altitude cut power way back or off if you have a folding prop. At that point you should be able to “glide” for several minutes before the next climb. Land with no power. The wings should not tip on you, or if turbulance does tip you the nuetral rudder and wing will quickly self correct.

Your big problem is going to be the prop will actually slow the plane down. Finding the right power to match the current speed will be you next challenge. Or get a folding prop so this problem goes away.

Personally, I would accept it is a now a powered glider and fly it that way. Getting the trim right is always an issue with these kind of planes. Aside from it wanting to loop on climb out, you might find in hands off glide mode it wants to porpoise (dive, pick up speed, climb to a stall and repeat). Again you will need down trim to stop this.

Good Luck

[phupper]

Thanks. Here's another concern I now have. I have cut off the up-bent wing tips. Do you think the remaining wing (almost flat), and the fact that it's mounted at the top of the fuse, will be enough to make the plane self-correct? I wasn't sure if high-wing planes without ailerons still need dihedral to be stable.

[pd1]

Thanks. Here's another concern I now have. I have cut off the up-bent wing tips. Do you think the remaining wing (almost flat), and the fact that it's mounted at the top of the fuse, will be enough to make the plane self-correct? I wasn't sure if high-wing planes without ailerons still need dihedral to be stable.

Stability is independent of control system.
A high wing is generally more stable than a low wing because the lifting surface is above the CG of the airplane.

Dihedral raises the lifting force even higher.

Some low wing airplanes are very stable, so it not a given that the high lift point will automatically make the plane stable.

Due to the size, weight and moments of you airplane I don't think you will lose much stability, if any.

The real question is will it turn without dihedral.
I suspect it will, but I can't say for sure.

Dihedral helps a plane turn with rudder control.
Without dihedral there is no clear answer.

I've had some planes that wouldn't turn with rudder without dihedral.
I've had some that did turn without dihedral.

If you had ailerons there wouldn't be any difference in controlling the plane.

Let us know how you make out.

Paul