My Vector40 Trimming Journey; It Used to be Fast, now Is It too Slow?

[Kafin Noe’man]

Hi,

It’s me again.
Last saturday, I flew my Vector again. I had like 4 flights but they weren’t as smooth as I hoped to be.

Some members here might remember that I was having a hard time to slow down my Vector lap times from 4.8-ish into around 5.20-ish.

My initial setup was:
Vector 40
Enya 35XS
APC 10.5x4.5
6.5mm venturi size
60’ lines
Tongue muffler
5% nitro fuel

So, in order to slow it down, I tried switching the tongue into its stock tube muffler. It actually worked to ‘tame’ the engine.

The RPM is dropped and I got slower lap time within the 5.50 and 5.80. But with this slower lap times, comes another problems.

1. I can’t do the sharp 90 degree wingover, everytime I try, the plane doesn’t feel have enough power to go straight up. I can’t feel any tension as well.

2. I can’t do the lazy 8 nor the entry for inverted flight. As soon as it reaches the top, followed by trying to make the entry for inverted, the plane somehow doesn’t feel to have power, it feels like it’s just free falling from the sky with no tension.

So, does this mean the plane doesn’t have enough power? Because as far as I remeber, I didn’t have these 2 problems when I was still using the tongue muffler and had faster lap times.

Looking forward to hearing and learning more from you guys!


Best,
Kafin

[Brett Buck]

Hi,

It’s me again.
Last saturday, I flew my Vector again. I had like 4 flights but they weren’t as smooth as I hoped to be.

Some members here might remember that I was having a hard time to slow down my Vector lap times from 4.8-ish into around 5.20-ish.

My initial setup was:
Vector 40
Enya 35XS
APC 10.5x4.5
6.5mm venturi size
60’ lines
Tongue muffler
5% nitro fuel

So, in order to slow it down, I tried switching the tongue into its stock tube muffler. It actually worked to ‘tame’ the engine.

The RPM is dropped and I got slower lap time within the 5.50 and 5.80. But with this slower lap times, comes another problems.

1. I can’t do the sharp 90 degree wingover, everytime I try, the plane doesn’t feel have enough power to go straight up. I can’t feel any tension as well.

2. I can’t do the lazy 8 nor the entry for inverted flight. As soon as it reaches the top, followed by trying to make the entry for inverted, the plane somehow doesn’t feel to have power, it feels like it’s just free falling from the sky with no tension.

So, does this mean the plane doesn’t have enough power? Because as far as I remeber, I didn’t have these 2 problems when I was still using the tongue muffler and had faster lap times.

Looking forward to hearing and learning more from you guys!


Best,
Kafin

  5.5 to 5.8 is way too slow, it needs to be substantially faster. There may be other issues with trim, but not one is flying these airplanes at those speeds, particularly not with relatively low-performance engine.

   I am also surprised that the muffler made that much difference, at these speeds I would expect minimal impact on the power. This is as fast as it will go?

     Brett

[M Spencer]

Ifin your lookin onna the You Tube , theres Very Few doing under 5.2 , no matter wot theysay .

IF you put it on 70 foot of .012 , you might be o.k. at  5.5 / + .

buton 60's youll ush & wallow .

As its an aeroplane & not a water buffaloo , you may need to do something about it .

Puta biga intake init

[John Carrodus]

Kafin , whats your launch RPM?
Maybe it'll handle a prop with more bite?
!0x6 maybe??

[John Carrodus]

Another thought. Have you changed anything else? Old fuel, new wheels , spinner or different tank?

[Dan McEntee]

Hi,

It’s me again.
Last saturday, I flew my Vector again. I had like 4 flights but they weren’t as smooth as I hoped to be.

Some members here might remember that I was having a hard time to slow down my Vector lap times from 4.8-ish into around 5.20-ish.

My initial setup was:
Vector 40
Enya 35XS
APC 10.5x4.5
6.5mm venturi size
60’ lines
Tongue muffler
5% nitro fuel

So, in order to slow it down, I tried switching the tongue into its stock tube muffler. It actually worked to ‘tame’ the engine.

The RPM is dropped and I got slower lap time within the 5.50 and 5.80. But with this slower lap times, comes another problems.

1. I can’t do the sharp 90 degree wingover, everytime I try, the plane doesn’t feel have enough power to go straight up. I can’t feel any tension as well.

2. I can’t do the lazy 8 nor the entry for inverted flight. As soon as it reaches the top, followed by trying to make the entry for inverted, the plane somehow doesn’t feel to have power, it feels like it’s just free falling from the sky with no tension.

So, does this mean the plane doesn’t have enough power? Because as far as I remeber, I didn’t have these 2 problems when I was still using the tongue muffler and had faster lap times.

Looking forward to hearing and learning more from you guys!


Best,
Kafin

     The muffler change shows that the tongue muffler was too restrictive. If it couldn't exhaust, it can't intake. By letting the engine breath, it became richer. You don't say whether or not you tried leaning the mixture out a bit for another flight?  This is where a tach comes in handy so you know what the engine is doing. Try increasing the RPM a bit and test fly. You can also experiment with regular APC 10-4 and 10-5 props. You slowed down by a whole second per lap, so now you just need to ease into leaning it out a little bit at a time to get the lap time to that 5.2 to 5.3 range. And increase in speed of half a second will make a big difference. Another option is to drill more holes in the tongue muffler to decrease back pressure.
  Type at you later,
   Dan McEntee

[kevin king]

If your flying on 60' lines from center of handle to center of airplane, flying on 62' lines may have helped you slow down the lap times on the original tongue muffler set up which you seemed to have been happy with. *I am not expert*

[Steve Glass]

If you are using an Enya 4mm nva then a 6.5mm venturi is too small?

[M Spencer]

youve moved the sea gee too .

[Kafin Noe’man]

Hi All,

I just wanna share you some updates of my experiments.

Having the stock tube muffler installed, I have succeeded to slow down my lap times but it was way too slow at around 5.7ish sec/lap.
The other thing that was affected by that installation of that tube muffler was the overall weight. I needed to add some tail weight to balance the CG but I ended up having too heavy plane. Thing also got worse since I changed my wheels from 2.5" into 3.5".

Thus, I tried to calculate the oz/sq ft of my Vector and my number was around 17oz/sq ft which was not ideal.
I was having a hard time to perform stunt with that setup.

Power decreased, but weight increased = I believe this is not a good recipe for stunt flying.

So, on last Saturday, I decided to go back to use the tongue muffler in order to have more power and lighter plane in general.
I also did change the prop size from 10.5x4.5 to 10x5.

I flew 2 times with 2 different launch RPMs:
1. First Flight 10,650 RPM -- the power was there and the lap times were nice in between 5.15 and 5.25. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

2. Second Flight 11,000 RPM -- the power was there and the lap times were too fast in between 4.70 and 4.90. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

I thought I had solved the problem by bringing back the power and stripping off the weight on the plane, but I was wrong.

What could've gone wrong here? There's no wing or flap or stab or elevator warp.
Could it be the tank height problem?

Looking forward to hearing more from you!
Thank you so much.


Best,
Kafin

[Steve Helmick]

Take a really good look at the Vector 40 from the rear and make certain that there is NO stabilizer tilt and that both elevators are exactly aligned to each other. Not being able to watch the model flying, I'd suggest adding some tip weight (clay or a coin with duct tape if you have to) to see if that might be the root cause.

If the lines go the least bit slack on takeoff, lack of tip weight can be a cause. As the model accellerates from zero, the tipweight will be resisting accelleration and due to leverage, will skew the model outward until reaching full speed. The main thing is that your model will live longer with significantly too much, but not live long with 1/4 oz too little tip weight.

What's the reason for changing from 2.5" to 3.5" wheels? I've never seen bigger than 2.5" on a stunter on any grass field, and many stay with 2". But of course, it depends on your flying site.

Regarding your engine setup...what is the maximum rpm you can get with the 10.5 x 4.5 and 10x5 APC? I want to know how rich you are below maximum. If you're launching at maximum, the engine will sag lean when you are doing tricks and most especially up high in the hemisphere. I like to peak the engine every flight by pinching the fuel or muffler pressure hose to see where it peaks on the tach. When it peaks at the same number twice, it's fully warmed up and I can then set the needle valve for the rpm that I am looking for. That will probably be 400 ~ 500 below peak, based on previous history.

Are you using the same fuel for all these flights? Is it good stuff, or possibly cheap or contaminated with water? 
Steve

Edit: Just figured that a 6.5 mm venturi is roughly .260", which I would suggest is too small for a 4 mm spraybar, but I don't know how big the actual spraybar is. I used .271"/.157" on my Magnum XLS .36 on a Twister, 11x4.5 Thunder Tiger propeller and OS .46 LA muffler. Killer combination. I think I launched at about 9,700 rpm, but beware that tachs aren't all identical...what works for you on your tach may not work if using your buddy's tach.

[Ken Culbertson]

Hi All,

I just wanna share you some updates of my experiments.

Having the stock tube muffler installed, I have succeeded to slow down my lap times but it was way too slow at around 5.7ish sec/lap.
The other thing that was affected by that installation of that tube muffler was the overall weight. I needed to add some tail weight to balance the CG but I ended up having too heavy plane. Thing also got worse since I changed my wheels from 2.5" into 3.5".

Thus, I tried to calculate the oz/sq ft of my Vector and my number was around 17oz/sq ft which was not ideal.
I was having a hard time to perform stunt with that setup.

Power decreased, but weight increased = I believe this is not a good recipe for stunt flying.

So, on last Saturday, I decided to go back to use the tongue muffler in order to have more power and lighter plane in general.
I also did change the prop size from 10.5x4.5 to 10x5.

I flew 2 times with 2 different launch RPMs:
1. First Flight 10,650 RPM -- the power was there and the lap times were nice in between 5.15 and 5.25. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

2. Second Flight 11,000 RPM -- the power was there and the lap times were too fast in between 4.70 and 4.90. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

I thought I had solved the problem by bringing back the power and stripping off the weight on the plane, but I was wrong.

What could've gone wrong here? There's no wing or flap or stab or elevator warp.
Could it be the tank height problem?

Looking forward to hearing more from you!
Thank you so much.


Best,
Kafin

What you are describing is stab tilt.  The plane can be warp free and fly perfectly level both upright and inverted until you give it control.  Check it out.  Your vertical CG has to be having fits with 3 1/2" wheels.  The vector is short on fuselage side area as it is.  Hope they are light.  Do you have equal tension on inside and outside loops?

Ken

Follow up - Steve's observations are 100% correct.  Tip weight issues usually manifest themselves both directions, unless there is a warp involved.  Then they may be masking the problem as well as exposing it.  If adding tip or nose weight helps, I suspect you have a warp that you are not seeing.  Are you blocking the plane up and using a gauge to confirm you don't have a warp.  Your eyes will lie. Repeatedly. 

At that wing loading you really can't be adding weight.  11-13oz@ft2 is pretty much the range for a competative stunter.  Some of our better fliers go over that a little but not 17.  That weight presents a whole different set of trim problems.  From what experience I have with the Vector 40 you are going to have to fly it fast at that weight. 

[Steve Helmick]

Good question, Ken. I think stab tilt...or elevator misalignment...is very possible. I reckon Kafin was looking for extra drag to slow the plane down with the bigger wheels? I'm also curious about line diameter. I'd hope .015's and not .018's. In the past, he's had problems at least partly from using the same lines and handle for multiple planes, but hope no longer.

Another mystery is having line tension problems in the lazy 8, but also "the entry to inverted". We know the entry to inverted is 3.5 inside loops, but maybe Kafin is just doing a half loop? I'm not sure. Perhaps he's doing the 1/2 loop or loops too small and losing a lot of speed and thus line tension? It's a common problem for rookie stunt fliers. Kafin, even if the bottom of the loop is at 3 meters, the top should be at something around 60 degrees elevation to keep the speed and lift up. The main thing is to get used to doing loops of equal size, both inside and outside, and plenty BIG to start.    Steve

[Brett Buck]

So, on last Saturday, I decided to go back to use the tongue muffler in order to have more power and lighter plane in general.
I also did change the prop size from 10.5x4.5 to 10x5.

I flew 2 times with 2 different launch RPMs:
1. First Flight 10,650 RPM -- the power was there and the lap times were nice in between 5.15 and 5.25. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

2. Second Flight 11,000 RPM -- the power was there and the lap times were too fast in between 4.70 and 4.90. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

I thought I had solved the problem by bringing back the power and stripping off the weight on the plane, but I was wrong.

What could've gone wrong here? There's no wing or flap or stab or elevator warp.
Could it be the tank height problem?

 If it is flying 4.7 seconds upright but loses all the line tension inverted, you have a profound/drastic/what have you trim issue, because you should be able to tolerate a huge warp or other issue with it flying that fast. My money is a warp and not enough tip weight. Put in another 3/4 ounce of tip weight until you can safely fly it inverted, then compare the upright and inverted roll angles. This will probably reveal that you need to tweak the outboard flap down to get the upright and inverted roll angles are the same.

    For reference, at that weight and 4.7 second laps it should be pulling *very hard* both ways, and with your problem as described, should be difficult to handle for a full flight upright (since I presume you have a large warp giving you more tension upright).

     Fiddling around with infinitesmal amounts of weight to try to meet some theoretical ideal of power/weight, you are nowhere close to even basic trim. I also note that going from a the correct muffler to a chip muffler also shifted the CG aft by quite a lot, that could have exacerbated the problem by also making it unstable. The Vector can tolerate a lot more aft CG than a lot of classic airplanes, but there is a limit to it. Put the CG at about 22% of the mean chord, add weight as necessary.

      brett

   

[Ken Culbertson]

If my math is correct your plane weighs around 63 oz.  That is simply too much for an Enya 35 to haul around.  That plane was designed for a weigh of about 45-50 ounces and powered by a .40 size.  However you have what you have and another motor is probably not worth investing in for a plane that heavy.  I am not a motor expert by any means but if you can do a 4.9 lap with a plane that heavy and don't have tennis elbow yet it may be salvageable if the Enya can take the stress.   Brett has pointed to your real problem.  BASIC trim.  Until you have the plane flying level both directions, maintaining line tension throughout the transition and not falling out of the sky when the engine quits you are not going anywhere.   

If a plane will not do a properly positioned lazy eight it is not safe to fly.  In any kind of wind you can do them with the engine off.  Do you have a workbench of sufficient size to block the plane up so it is truly level?  It doesn't take much, I use a small cabinet in my disgustingly small office.  Get an incidence gauge, like a Robarts, and block the plane up perfectly level at the WING CENTER CHORD.  Now measure everything using the gauge.  If you can get a simple painters laser level you can check a lot of other stuff as well like thrust angle.  Without this kind of setup you are going to miss the one thing that does not show up using visual references - twist.  If a wing is twisted, both sides will appear straight when you eyeball them thanks to the fuselage.  Same with the stab which may be twisted or alligned to the TE of a twisted wing.

While you are bench trimming check for a weak flap.  Pull the leadouts till you have full deflection and see if you can move the flaps.  If one moves more than the other one you may have found your whole tension problem.  If you think there is not much pressure on the flap surface, stick your hand out the car window at 55 mph and angle it up.  It is compounded by the planes weight.  Check them at the center and at the tips.

All of that, and more, gets you to "BASIC Trim" which simply means the plane is safe to fly and you can start the process of actual trim.  Too many of us, and I am very guilty of this one, stop at basic and just adapt to whatever is left.  If you have any aspirations of serious competition learn the art of trimming.  It is an art and there are masters of that art on this forum.  I am a novice compared to them.

Ken

ps - I am fortunate to fly with a very advanced set of fliers.  When a new plane hits the circle it has several hundred years of collective experience watching it.  Basic trim is accomplished in a couple of flights.  I suspect that you do not have that good fortune so you are reliant on what you can pass on to us on this forum.  You are doing a good job passing on the technical attributes which helps.  You sometimes post video.  This is one of those times where a video would really help - Keep it up!

[Colin McRae]

Hi All,

I just wanna share you some updates of my experiments.

Having the stock tube muffler installed, I have succeeded to slow down my lap times but it was way too slow at around 5.7ish sec/lap.
The other thing that was affected by that installation of that tube muffler was the overall weight. I needed to add some tail weight to balance the CG but I ended up having too heavy plane. Thing also got worse since I changed my wheels from 2.5" into 3.5".

Thus, I tried to calculate the oz/sq ft of my Vector and my number was around 17oz/sq ft which was not ideal.
I was having a hard time to perform stunt with that setup.

Kafin, in a different post you had mentioned that your vector weight was 45 oz. At 45 oz, the wing loading would be 12. But now you are saying 17 oz/sqft. So, what changed?

I am also struggling w/ a heavy vector at 62 oz. I run an OS 46 LA and currently w/ an APC 11-4 prop. I also tried a 12-4, but did it see much difference. The APC 11-4 has a wider airfoil compared to the narrower APC 12-4.


Power decreased, but weight increased = I believe this is not a good recipe for stunt flying.

So, on last Saturday, I decided to go back to use the tongue muffler in order to have more power and lighter plane in general.
I also did change the prop size from 10.5x4.5 to 10x5.

I flew 2 times with 2 different launch RPMs:
1. First Flight 10,650 RPM -- the power was there and the lap times were nice in between 5.15 and 5.25. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

2. Second Flight 11,000 RPM -- the power was there and the lap times were too fast in between 4.70 and 4.90. I could do the 90 degree sharp wingover easily, but as soon as I started making an entry for the inverted flying, I lost my line tension. It felt like the plane didn't wanna go 'outside' when inverted. Engine and rudder offset are there, leadout guide position is 1 inch behind the CG.

I thought I had solved the problem by bringing back the power and stripping off the weight on the plane, but I was wrong.

What could've gone wrong here? There's no wing or flap or stab or elevator warp.
Could it be the tank height problem?

Looking forward to hearing more from you!
Thank you so much.


Best,
Kafin

[M Spencer]

Probably irrelevant . Fuel Tank - feed pipe .

If its the small bore thick wall copper tube , its not irrelivant !

we Recalled after YEARS , With the G - 15 , when we went to 10 % Nitro ,
Not Only did it need 110 cc instead of 80 , to get past 4 minutes ,
The COPPER TUBE fuel feed was inadeqate . Like on the NEW one ! .

Equates to a . 35 stunt engine . Maybe even a .30 .  The FSR with this ' irregularity ,
got me doing a motor change , Had thought Id used a bigger bore pipe ,
LAST thing on the change was The TANK . WHAT , Id thought it was #Ietc  .
Bit of a let down , went well with the G 51 BUT , all it had needed was a bigger FEED PIPE .

Sounds stupid , but youd lack get up & go . They used to say " If it dosnt fly , put a Supre Tigre 60 in it .
HORSEPOWER can cover a multitude of sins . As its not ' at the edge ' they dont become apparent .

Can you find a ball race schneurle . 40 / 46 / 50 , as the ease with which a big one will tow it will make life easier for you .
Most R C motors can be got workable , with just a venturie and NVA . You could bung the by pass to make it a ' thumper ' .
Less rpm more pitch . but thats unecessary . The ENYA . 35 would be very happy with 50 ounces 56 may be about the limit
Even there , youd know it by the loss of speed under duress .

IF it flys inverted o.k. from insides - TIME it . Do half a dozen laps level each way . If the times are similar , The tank hights workable .
On a video you time it there , so as not to get distracted . as they say in the U S of A ; theres no sustitute for cubic inches .

Imagine a Morris Minor , driving a twisty switch back road . Now , We'll drop a 5 litre V8 in it . See the Differance . No replacement for displacement . This will do the trick .




 

[Colin McRae]

Kafin, in a different post you had mentioned that your vector weight was 45 oz. At 45 oz, the wing loading would be 12. But now you are saying 17 oz/sqft. So, what changed?

I am also struggling w/ a heavy vector at 62 oz. I run an OS 46 LA and currently w/ an APC 11-4 prop. I also tried a 12-4, but did not see much difference. The APC 11-4 has a wider airfoil compared to the narrower APC 12-4.

Another engine you might consider is an Evolution 36 NT. It is a higher compression BB engine and out spins an OS 40 LA. Probably even a bit more powerful than a 46 LA. Also, slightly lighter.

[John Carrodus]

Hiya Kafin
Did you ever put the tongue back and try it again to get the speed you had before?

[Kafin Noe’man]

Hi Steve, Ken, Brett, Colin, and Air Ministry,

Thank you so much for your responses. It means a lot to me to read your thoughts in order to solve my problem I’m facing now.

It’s true that I’ve made some changes and experiment in the past few weeks that caused my Vector to be heavier, but I decided to go back lighter. So to clear things up, I’m listing my latest setup as of September 9, 2023

Vector 40
Enya 35XS
APC 10x5
6.5mm venturi size
0.015 x 60’ lines
Tongue muffler
5% nitro ; 20% oil
Leadout position 1 inch behind the CG
Wingtip weight 1.75 oz
Overall Weight 53 oz
Wingload 14 oz/sq ft
Lap Times 5.15-5.25 (wet 2) or 4.70-4.80 (perhaps too lean 2 cycling)

I hope I’ve listed everyting to give you better understanding of my Vector’s latest condition.

With the setup above, the power and speed are back. I could do the wingover very well, but I still had some problem with the lazy 8 and going inverted, I lost the line tension.

As far as I can remember, the last time my Vector could do the lazy 8 easily and properly was when I was having 2oz and the rest of the setup pretty much the same as I mentioned above, except the prop was APC 10.5x4.5.

The main reason why I tried to reduce the wing tip weight on Sep 9, 2023 was because I thought the 2 oz tip weight was too much. I could see the outboard wing tilted down when landing. Please see the attached picture.(This picture was taken on June 1, 2023)


So, after reading your comments and try to reflect to my past flying experience, I think the main culprit is now narrowed down to not having enough of tip weight or the wrap or twist or tilt on the wing or stab alignment.

My next move is I will check everything that is related to the alignment of wing, elevator, fuselage, and everything else, but I will also try to fly it one more time with some more tip weight.

Any thoughts?


Best,
Kafin

[Brett Buck]

So, after reading your comments and try to reflect to my past flying experience, I think the main culprit is now narrowed down to not having enough of tip weight or the wrap or twist or tilt on the wing or stab alignment.

My next move is I will check everything that is related to the alignment of wing, elevator, fuselage, and everything else, but I will also try to fly it one more time with some more tip weight.

Any thoughts?

   Please, please, please. stop worrying about the weight, particularly the small variations you are doing. You have to get it in trim and the engine running properly, and flying reliably, and then and only then consider whether it is too heavy or not. I can tell you the answer already - it is not too heavy and the all-up weight is not causing your problem!

  There are about 4 things that could cause your airplane to roll away from you like that, but if it is different inside and outside, you need a tweak. The roll angle in your picture could very easily be a combition of not enough tip weight, but a warp causing it to roll away from you despite that. That is certainly what your description sounds like.

  You have to get it to the point you are able to safely fly level inverted, then do the same sort of roll angle check in both directions. Only then can we separate the two different effects. I would very strongly suggest you inspect the wing and flaps for proper alignment and warps, because if it is as bad as you say it is, it will not be a subtle minor twist somewhere that only a calibrated eyeball can see, it sounds like it is way off, and should be very easy to see. Note that if it is having effects in level flight, is is almost certainly not a stab tilt or skew, because the stab is doing very little lifting unless you are in a hard corner;  no lift, it doesn't care which way that lift it aimed.

    To check you wing and flaps, do this: Tilt the airplane nose-down, and put the spinner on the top of your shoe. Look down on the trailing edge and flaps. At the root of the wing, center the trailing edge between the upper and lower surface of the wing, and center the flap on the inboard root unti the flap TE is line up in the center, as well. Then, without moving it or your head, sight out to the tip, and see if both the wing TE and flap TE is centered. If not, it is warped. The sight out to the other tip, same thing. Compare the flap at one side of the fuse to the flap on th eother side, those should both center up.

    My very strong guess is that the flaps are not level with each other at the root, nor are they straight. From your picture,  can almost convince myself that I can see the outboard wingtip warped "up" at the TE, which is the right direction to cause your issue. Double the resolution and we would be able to see it, and I can *usually* see relatively small warps with the naked eye when someone else is flying. We aren't looking for a small tweak, your description indicates a pretty large warp that someone should be able to see it if they were watching.

     Brett

[M Spencer]

    My very strong guess is that the flaps are not level with each other at the root, nor are they straight.

Yep . Stand back , hold rear at arms length , Steely Eyeball level with FLAP at ROOT , One Side . IF you see the UNDER or TOP side , anywhere , warpy twisty .

WITH YOUR CLIMATE ! as here in Australia , the Humidity / De Humidity , and SUN can be a bit of A BOTHER . One Plane I have is o.k. ( left in the sun ) Upside Down .
More than a half hour upright , In The Sun , the wings twisted . Elevators to can CURVE or Twist ( Both are types of warp . Though are not ropes  , which can be    )

Putting it on a table , a block under the rear to level , stand back two or three metres . Block one eye . Sight the surfaces .

TRAVELING in a CAR , if its leant angled , the sit and joggling can get them - Twist Wires . SITTING in a car like that = the boggy man will have a go at it , if the suns out .

CARE traveling & In Storage . Might be a TOPIC .

Leaving Wing Spars on the WINDOW SILL , centuries ago , as I built a wing - Spar on board , Trailing Edge - Fit Ribs , Get top 1/4 Sq Spars of windowsill Fit .
In the Morning - it had ' cresented , as the top one had been dried more . Or Something . A week later cut the ribs free at top and refitted . Spar NOT on the windowsill IN THE SUN ,

SAME PROBLEM  wing on wall in horendous freezing hovel with raging fire . The frozen against the wall side was a DIFFERANT LENGTH to the something resembling near unfrozen side ( top / bottom )
facing into the room .

If you have a high humidity hot  climate with heavy rain , a stable storage and transpot  is required . even in a car boot , if a edge of the end of the wing or back end is ' on a wheelarch / or LUMP ,
It can upset the alignment .
So No Casual loading or storing .

Perhaps . Some planes have the Warp Bug , others are way more resistant .  Store CAREFULLY . Transport carefully . A lot of guys will put the plane IN SHADE at the field . Or cover it with a thermal rug . The silver things .

[M Spencer]

Try 20 % NITRO . Underpowered its not getting the opertunity to kick itself straight . Like a long uphill on a bicycle - as a analogy . 52 foot lines it might , But You Need GRUNT .

Its operating at the EDGE of the envelope . you want it In the Middle . Or itll skive off and get troublesome .  Give it a good kick in the balls and it'g GO like a scalded cat .
a 9 x5  prop , while not being aerobatic , would let the engine get into its outright horsepower .it  produces the power you require at 16. 000 odd rpm .  10.000 is still way off peak power .
A Big Engine LOAFING ( 10.000 ) will get the POWER you need for that weight . You require a POWER SURPLUS , Put the ENGINE , the .35 in a 50 ounce plane , THEN It'll work very well .

[Brett Buck]

Try 20 % NITRO . Underpowered its not getting the opertunity to kick itself straight . Like a long uphill on a bicycle - as a analogy . 52 foot lines it might , But You Need GRUNT .

  At 61 foot radius, 53 ounces, and 4.7 seconds/lap, it should be pulling something like 11 1/2 pounds! and even if it  rolled 45 deg  towards him in level flight, it would be pulling something like 6 lbs. Speed is not the problem here.

     Brett

[M Spencer]

It was 63 ounces on Charles group chat . Mustve dried out some ? or were the scale batteries flat . 

Around 1:12 tho He just said 58 ounce , where I caught it THEN . 

[Kafin Noe’man]

It was 63 ounces on Charles group chat . Mustve dried out some ? or were the scale batteries flat . 

Around 1:12 tho He just said 58 ounce , where I caught it THEN . 

Hi, please refer to this data

It’s true that I’ve made some changes and experiment in the past few weeks that caused my Vector to be heavier, but I decided to go back lighter. So to clear things up, I’m listing my latest setup as of September 9, 2023

Vector 40
Enya 35XS
APC 10x5
6.5mm venturi size
0.015 x 60’ lines
Tongue muffler
5% nitro ; 20% oil
Leadout position 1 inch behind the CG
Wingtip weight 1.75 oz
Overall Weight 53 oz
Wingload 14 oz/sq ft
Lap Times 5.15-5.25 (wet 2) or 4.70-4.80 (perhaps too lean 2 cycling)

I hope I’ve listed everyting to give you better understanding of my Vector’s latest condition.

[Kafin Noe’man]

Hi Brett and all,

I have finally solved my Vector problems now.

It was indeed the wing and stab were not in parallel to each other.
The wing had some warp, and the stab was tilted.
So, I steamed the wing, recut the stab, realigned everything, and reglued the stab to the fuselage.

With the APC 10x5, the plane was flying really well at good lap times in between 5.15 sec/lap (when set wet 2-2-2) and 5.35 sec/lap (when set 4-2-4).

Thank you guys for your input, it really helped me a lot.
I’m so happy that my Vector is back and flies much better now!


Best,
Kafin

[Brett Buck]

Hi Brett and all,

I have finally solved my Vector problems now.

It was indeed the wing and stab were not in parallel to each other.
The wing had some warp, and the stab was tilted.
So, I steamed the wing, recut the stab, realigned everything, and reglued the stab to the fuselage.

With the APC 10x5, the plane was flying really well at good lap times in between 5.15 sec/lap (when set wet 2-2-2) and 5.35 sec/lap (when set 4-2-4).

Thank you guys for your input, it really helped me a lot.
I’m so happy that my Vector is back and flies much better now!

    Glad to hear that!  These sort of alignment, construction, and engine setup issues are sort of boring and pedestrian  - but are almost always the determining factor. You have to master these sorts of problems before you can even begin to discuss all these other things like airplane design, minor variations in weight, which engine is better than which other engine, etc. And I can tell you right now that many people never get past the very first step of building airplanes straight with sound control systems, or getting the CG and tip weight right, never mind the rest of it.

     I know that stunt fliers tend to be obsessive over every minor detail, the event selects for people like that. But what usually trips them up is the very simplest stuff that frequently gets skipped over looking for something subtle or tricky.

      Brett