Do you have the anti-spin devices taped on the wing? Mine did the same kind of thing and would not fly straight until I removed them from mine. You might try that to help your problem. If they are like mine, they are just taped on and can be re-installed if you want to. Personally, mine went right into the trash. the plane flys a lot better now and a little faster.

Winghawg1 -- From the look of your work, you don't need a hero -- you're one yourself.

Regards

britbrat

The anti spin devices don't have a thing to do with going down the runway straight, I keep mine on for the slow landings. I moveed the engine a little when I installed the Saito 56 4 stroke. Mine rolls straight for about ten foot then she's off, it used to always go to the right alot.
Britbat you forgot to give me your opinon on the wing thing. One thing I have learned is do whats best for you and learn from mistakes. I am fixing to modify another one so it should look even better. I just need to learn to cover one a different color, I like yellow and red.

Gear goes at the leading edge of the wing, there is a support there I used to keep things lined up the add balsa in 2 layers to hold gear and break away 1/4 nylon bolts x 3 they also hold fuel tank in better and but my battery there behind the tank, the long bolts hold it securely.

The "wing thing" (removing dihedral) is arguably the most important mod that you can do to this bird.

The easy way is to bend the steel rod, bit-by-bit, until the wing lays flat & then fill the central wedge-shaped gap with balsa wedges & Probond. Drill a hole in the LE for a 1/4" dowel & drill a new hole for the wing hold-down bolt (reinforced with a ftat plate of 1/16 ply) & away you go.

I prefer to cut into the end ribs & glue in a hardwood wing joiner against the mainspar, and add a 1/8 ply LE wing joiner up front. The gap is filled as noted above. This is more work, but it is lighter & a bit less flexible.

I always add dual aileron servos to a Nexstar wing mod -- this eliminates any chance of aileron flutter.


As noted by Winghawg1, the LE droops don't have any influence at all on take-off stability.


Another important & very easy mod, is to eliminate the right thrust & re-center the engine. I straighten the firewall with a balsa wedge, then cap it with a layer of 1/8 ply before re-mounting the engine dead center. In the case of a crash repair, I actually completely replace the firewall with a 1/2" thick ply piece, laminated up from layers of balsa & ply. I also pin the firewall from the sides with #4 screws.

They do indeed affect the way it runs down the runway. If they are not installed correctly, they can cause a bank to the right (in my case) just before it has enough air speed to lift off. Mine had a hard break to the right before it left the ground until they were removed. Several people tried it and had the same experience. You could not see it, but it appears they were not installed exactly in the right place causing un-even lift on the wng tips. When the plane was flying, it needed a little left aileron to fly level and that caused it to crab slightly. After removing the devices, the take off was much more predictable and controllable and the plane flew straight. It is possible that they could have been re-installed correctly and not had the problem, but the plane flew so much better I decided to leave them off.

Me, too! I love my taildragger Nexstar. I'll have to post some pics. I like the idea of a four stroke, and am considering the Saito 56.....

i trained on the nexstar and had the same problem. the problem i had was the nose wheel does not fit snug into the motor housing and therefor has alot of slop. also the pre filed top of the nose gear i think was filed at the wrong angle wich makes it very hard to adjust the nose wheel straight. you might look at that and maybee re file a flat spot at the top of the gear to get the wheel straight with the plane. as far as any slop maybee theres a way you can thicken up the top of the gear to get a snugger fit into the motor mount.

You could try one of these to stiffen up the nose strut. You would need to drill the mount for a 3/16 wire. I have used these in other planes and they work well.

http://www.fultstooling.com/page7.asp

Tower carries them or maybe your LHS too. Wire sizes listed in Tower are wrong though. Go by Fults listing.

They do indeed affect the way it runs down the runway. If they are not installed correctly, they can cause a bank to the right ---[/quote]


I don't want to get into a scrap over these things, but I don't see how they can be installed incorrectly -- they are as simple as dog-dirt. I've also seen them seriously mangled, including chunks missing, and repaired with lumpy applications of tape without affecting anything much at all, including in-flight performance.

IMHO, the real problems can be attributed to:

1) pilot inexperience
2) incorrectly configured nose-wheel linkage
3) pilot inexperience
4) incorrect right thrust
5) pilot inexperience
6) cross wind sensitivity, due to substantial dihedral
7) pilot inexperience
8) toe-out or looseness in the main gear
9) pilot inexperience
10) sticking main wheels
11) pilot inexperience
12) uneven runway surfaces
13) pilot inexperience

I'm not dissing anyone here, but flying these things isn't difficult & taking off isn't either. The excitement goes away with a bit of practice. A good pilot can whisk one of these birds straight down a runway in a stiff cross-wind, even having to two-wheel the thing with the upwind wing rolled into the wind. Inexperience is just that-- inexperience -- it goes away with practice.

I don't want to get into a scrap over the anti spin devices, but I don't see how they can be installed incorrectly -- they are as simple as dog-dirt. I've also seen them seriously mangled, including chunks missing and repaired with lumpy applications of tape, without affecting anything much at all, including in-flight performance.

IMHO, the real problems can be attributed to:

1) pilot inexperience
2) incorrectly configured nose-wheel linkage
3) pilot inexperience
4) incorrect right thrust
5) pilot inexperience
6) cross wind sensitivity, due to substantial dihedral
7) pilot inexperience
8) toe-out or looseness in the main gear
9) pilot inexperience
10) sticking main wheels
11) pilot inexperience
12) uneven runway surfaces
13) pilot inexperience

I'm not dissing anyone here, but flying these things isn't difficult & taking off isn't either. The excitement goes away with a bit of practice. A good pilot can whisk one of these birds straight down a runway in a stiff cross-wind, even having to two-wheel the thing with the upwind wing rolled into the wind. Inexperience is just that-- inexperience -- it goes away with practice.

So Britbrat, do you think "pilot inexperience" may be the problem? You weren't very clear on that.

BINGO

Buy the way Bruce's link to the Fults gear while it won,t help the original posters problem is in fact excellent nosewheel assemblys. They are fantastic on any airplane that is likely to take a beating. I have used them on two four engine airplanes and love them.

John

BritBrat

Believe what you want but if one is high on the wing and one is low on the wing, they WILL affect the way air flows over the wings and cause the plane to exhibit odd behavior. After all, the reason they are on the wing in the first place is to change the shape of the airfoil to help prevent spin. It would be the same as putting a small amount twist in one side of the wing, it just won't fly right.

Or do the laws of physics and aerodynamics work differently north of the border?

Sure all of the things you listed could cause the problem when taxiing down the runway, but not the stall to the right when lifting off the ground.


As for experience, I am by no means a new pilot as I have flown for many years and have built and flown many aircraft and this is the only one that has had this problem. Which by the way, magically disappeared when they were removed from the wings. Of course I am sure that it was just my experience level that magically improved in the 10 minutes it took to remove them and not the fact that they were the cause. Could I take off and fly the plane before I removed them....YES. Did it take off much better when they were removed...YES.

Just because you don't understand it don't mean that it ain't so!

Like I said, I don't want a scrap & I wasn't dissing anyone. I have flown Nexstars several times a week since they first appeared & I just haven't seen an airframe-related take-off difficulty that could be attributed to the anti-spin devices. Warped wings, yes, excessive side thrust, yes, & a bunch of landing gear & runway issues as well --- but not the add-on wing cuffs.

It might help if you described how one could be high on the wing & the other low on the wing. They are pre-shaped to fit tightly against the wing in a specific attitude, and they are graphically marked for simple spanwise alignment. Obviously virtually any defect is possible in a manufactured product -- I'm missing some information here that is clearly of significance. Do you have a pic? -- that would help.

No pic of the problem as they have been disposed of. My Nexstar was an RTF and they were installed from the factory. After removing the tape, they could be rotated up and down the leading edge quite a lot actually and still appear to have good contact with the wing. I would guess the difference from one wing being all of the way up and the other being all the way down could be as much as 1/4" when measured at the extreme leading edge of the devices. This is only an estimate since I did not care to measure them at the time. This would be the same effect as the wing being warped or twisted. With them installed, the plane would make a hard right turn when lifting off of the runway and fly in a crab that could only be made better with the addition of rudder. After removing them, the plane flys straight and true with hands off.

I've seen a couple of Nexstars with severly exagerated right thrust, that behaved like that -- one was actually unflyable & both were replaced by Hobbico -- but I've never seen (perhaps noticed would be better) any problems with the cuffs.

Experienced pilots invariably prefer the way the plane flies without the cuffs (myself included), but we already know how to fly & how we like a plane to "feel'. I have experimented with removing & replacing the cuffs on student's planes at various points in their progress. The results are quite interesting. Totally inexperienced student pilots that show little natural ability, invariably prefer the plane with the cuffs & speed brakes in place. The same students at a later point in their flying skill development, prefer the devices removed -- not a surprise. However, inexperienced pilots with demonstrable natural ability, seem to prefer the cuffs & brakes removed, despite not knowing how they work, or what a plane normally feels like in the air.

I personally don't like the idea of learning with all of the devices in place for two reasons:

1. New pilots read all about these aids and think they can learn on their own.

2. After you learn to fly with them, you must re-learn with them removed.

Face it there is no substitute for an instructor when learning. The mechanics of flying are only a small part of what you need to know to fly safely and most of those things you cannot learn alone. If you have an instructor to help, why bother to learn twice? Your second plane will surely not have those aids to help you along.

Britbat do those things really cause much difference in the way the plane fly's, guess I 'll take off mine and see. Well I did the wing thing today, it is flat as a fritter, will post pic tommorrow, only problem it binds some need to redo the dowl hole I guess.

My Nexstar always veers to the right shortly after takeoff. It's kinda neat in a way. It looks like I am trying to make it do that. Really consistent every time. I think I will take the cuffs off next time I fly it and see if that problem goes away. I too had problems trying to take off in a straight line until I found that the flat spot for the set screw was way off where it should be on the nose gear. Ground a new "flat" in the correct place, end of problem. I also ground out the pocket that the spring recesses into. It was way to close to suit me. Just my 2 pennies worth.

The plane doesnt really FLY too differently without the swoops unless they are installed wrong..it STALLS differently...

Britbat...I hear what you are saying about "inexperience".....can't argue that. But I along with others with alot more knowledge than me
believe there is something not right...........SO.......today, I changed the 2 1/2 " sponge tires to Dubro 5 1/2" rubber tires hoping for a
little better grass field take off control.........NEXT......I took out the front hear RE-flattened a little larger area with a new control arm and
also was able to raise the front gear about 1/4" hoping it will help with a little "quicker" lift off.

Again.....I AM LEARNING MORE EVERYDAY.....THANKS TO ALL OF YOU GUYS INPUT.

If this doesn't do it.....or at least make it "tolerable" I will look into the thrust issue.

Oh....also forgot to say.....I took off the "adds" that came with the plane before I ever flew it......Never used them......and as for
the crosswind issue.....I handle that (so far) just fine in my landings.

Thanks to all your help....I think I will get it figured out.....hope this weekend will tell the tale.....but if it continues........at some point
down the road......it may make an awsome DIVE BOMBER...on a one way mission........lol

The speed brakes are just that. Without them, the plane is noticeably faster & has a longer & flatter glide -- it floats more. With the brakes on, the descent is steep & slow -- great for spot landings, but really bad if you dead-stick any distance from the runway.

The wing cuffs also cut top speed, & not surprisingly, reduce landing speed -- it's quite a bit faster at full throttle & noticeably faster landing without them -- again a longer & flatter glide (still more float).

Both brakes & cuffs affect agility and seriously degrade inverted flight capability, although at that stage, students won't be doing anything needing serious agility & won't be flying inverted. With the brakes off, & the cuffs on, the Nexstar has reasonable inverted capability & is agile enough for simple aerobatics. With everything removed, the Nexstar is pretty fast for a trainer -- just about 70 MPH, and once the throws are cranked up it can do quite respectable aerobatics, including hovering, a wobbly knife-edge & outside loops.

The plane needs re-trimming when the bits are removed, but this is to be expected.

1) Agreed

2) The only aid that creates bad habits requiring later correction, is the AFS -- & I don't let my students fly with the AFS -- it is specifically designed for self-teaching -- which we all discourage.