abufletcher

Here it is. Looks like the outer wings (top and bottom) are a bit "rotated forward." I don't mind changing some wires...as long as I know what needs to be fixed.

Maybe I'm just not understanding "washout" properly.

jack steward350

My Feedback: (7)

OK, Here is Dave Platts specs for the incidences on a precision scale Se5: Set the model up so the stab and elevator are at 0 degrees. Check the bottom wing, It needs to be at 0 to +1 degree. It is alowable to have slight positive incidence in the top wing relative to the bottom wing...slight. Those are correct for the Se5. From the photos there is more wash out in the right wing. He recomends adjusting this by lengthening, or shortening, the outer struts. Another method that will work, these are my thoughts not Mr. Platts, would be to deflect the right bottom aleron using the control linkage so that the aileron has 1 to 2 mm up deflection. I have used this method before and it will work. Adjusting the struts would be best but this would yeild the same effect of adding wash out to the right lower wing. You could do this as well to the top right aileron but from the photos it looks fine to me the way it is. No need for a rear view of the wings as the photo did reveal the problems with the wings clearly.

As for the engine thrust line Mr. Platt calls for 0 0 degrees....GET RID OF THE DOWN THRUST IN THE ENGINE AND MAKE DARN SHURE THERE IS NO LEFT THRUST. to me, from the photos, there appears to be left thrust but an accurate measurement of this would be helpful to tell for shure. That really is a beautiful model. You did an outstanding job on it. My compliments

TFF

The TF stab is technically -5 or full down trim of the real plane; 0 on the top fuselage. I see from the front twist on right bottom and left upper; you can argue left bottom and right upper. Mine is not any straighter. How much control throw do you have as it needs a lot. I think I ended up with different sub trims on each of the aileron servos; My ailerons do not center on the trailing edge. To fix mine would mean building a new airplane so I have trim mechanically and electronically added in.

Michaelj2k

For performing a weight and balance exercise, the manufacturer designates leveling points somewhere in the fuselage. similiarly for your SE5, good leveling points would be the upper fuselage longerons. Set it to level in an "X" (longitude) and "Y" (lateral) axis then take your measurements. It helps if your table is also level.

jack steward350

My Feedback: (7)

Well I can take a photo of exactly what dave Platt wrote about the incidences on the top flight model as he designed it. I would gladly do that if it would be helpful to you. Although what I wrote were his words and not mine in reguards to the incidences on that model. I will do that so you can read it for yourself. I would think that the wash out issues with the wings could easily be corrected with the trim adjustment but apparently you have done this durring test flights and it did not. It would be helpful to know how the airplane flies with power on and how it flies with the power off at idle. There should not be any great differences between the two only slight differences. If there is a big difference this would indicate an engine thrust issue. I would be surprised if the control throws have anything to do with how the model is misbehaving but if there is any left thrust in the engine that would and in a big way. I know that there is lots of down thrust from the photos and that is not right needs to be at zero. Control throws are probably not the issue but do you have diffential in the ailerons, more up deflection than down deflection? This helps make better more balanced turns but I am shure you know this and do not mean to be insulting in any way. From the photo the top wing looks fine to me but yes that is arguable :-} Look at the top wing from the rear straight on at the TE it will tell you lots. Clearly you need to change something and give it another go and see where it is at. My main concern is the engine thrust and making shure it is 0 0 and particularly that there is NO left thrust. I know your delema and have been there myself more than once.

Nieuport nut

My Feedback: (10)

I think trimming with rudder on your test flights would have been more effective than with aileron.

Warps are curious things, Sometimes the slightest misalignment makes a plane unflyable, and other times we can fly potato chips!
I do like the ASAP reference - as straight as possible - always good advice.

Martin

FireBee

My Feedback: (34)

Abu! Based on post 2 pic: using left/right references too open for error so port and starboard from any way you look at it.

Appears the port lower wing has a a bad twist in it. Too much washout. it is acting like a raise left lower aileron with the trailing edge up so high.

Also noting picture with CF sticks, appears top aileron and lower port ailerons are different. Can you raise the ailerons and remeasure? Lower port aileron appears raised up more than top wing.

A large twisted wing is what I got When a strut failure I had last weekend on 1/4 scale Nieuport: causing a large roll ( 30-45 degrees) Took a lot to get her back safe.

Second item is appears center top wing section is pulled slightly towards the port side of the plane. The cross bracing between the cabane struts is causing this and needs adjusting. Try one Clevis turn in, and the other one Clevis turn out on the wires until centered.

The stick method works great, but I just bought a digital pitch gauge to back it up. Here is 1/3 Pup I am finishing rigging now!

FireBee

My Feedback: (34)

Solution: loosen up the incidence wires between the port N struts. re twist the lower wing while applying heat to the covering to take out so much washout. Also need to check the length of the rear struts on both side are the same. Perhaps the port aft strut was cut a little short allowing the wing trailing edge to rise (twisting the wing).
then retighten the incidence wires to get the wing to hold the correct incidence on the port lower wing panel.

I also think the thrust line double check its right 2 or zero as mentioned earlier. I still use 3 right/ 3 down on all of my warbirds engines.
i hope this helps.

jack steward350

My Feedback: (7)

Those incident settings I refered to are relative to the stabilizer being set at 0 degrees to the work surface not the centerline. Stabilizer is + that's a + 5 degrees to the cenerline, Bottom wing + 5 to + 6 degrees to the center line, top wing +5 to + 6 degrees to the center line depending on the incidence of the bottom wing. Bottom wing and top wing idealy have the same incidence but slight positive incidence of the top wing relative to the bottom wing is, as the designer of the model put it, " allowable."

jack steward350

My Feedback: (7)

Those incident settings I refered to are relative to the stabilizer being set at 0 degrees to the work surface not the centerline. Stabilizer is + that's a + 5 degrees to the cenerline, Bottom wing + 5 to + 6 degrees to the center line, top wing +5 to + 6 degrees to the center line depending on the incidence of the bottom wing. Bottom wing and top wing idealy have the same incidence but slight positive incidence of the top wing relative to the bottom wing is, as the designer of the model put it, " allowable."

abufletcher

First of all, thanks for all the advice and suggestions. Clearly there are a lot of things to check before I attempt to fly it again (which is fine given the weather we're likely to have for the next month or so).

Some aspects of the model are just not modifiable at all. For example, there is no way to alter the root incidences of the lower wing since this is established and fixed by the scale "winglets" as well as 3mm music wires passing through the fuselage/winglets into to the wing panels. Also there is no way to adjust the incidence on the stab, at least no way that wouldn't involve major surgery.

The engine is mounted on wood beams which are at 0 relative to the aircraft center line (which is what I take 0 to mean). Relative to this center line the stabilizer sits at +3 and the root of the top wing sits at 4.5 degrees. The root of the bottom wings also appears to be at 4.5 degrees. The incidence of the top wing (which also have the 3mm music wires passing through the center section) could be adjusted by raising or lowering the center section on the ends of the cabane struts.

I'm pretty sure the struts are all the correct length and I sure wouldn't like to use unequal struts to correct a problem...unless there is just no other choice.

Anyway, lots to think about. Thanks again.

ARUP

I wouldn't worry about the stab presently. Totally remove that from the picture for now. Block the fuse good and solid... no weight on undercarriage at all... you don't want it to move. Block fuselage so that lower wings are positive 1 degree at root. Remove top wing!!!!! It's gotta be done to get done... right! Build a jig for each lower panel to set at outer strut locations to match the incidence with dihedral and go ahead and build washout into jig. The jigs need to be attached to the board and the wings need to be held firmly. Put upper center section back on and put it at '0' incidence. It is easier to shim the mounting locations than trim struts, etc. Put the upper panels on without any bracing. Make cardboard jigs to hold them up. The purpose of this exercise is to align the center section in plan view while re-rigging it. You use the outer panels for 'sighting' and measuring to keep center section square. You are very familiar with the drill. Use your incidence meter for this. Once the center section is done the rest follows. Hang (already jigged in place) the lower panels with landing wires, install struts, put in 'X' bracing then finish flying wires. If you don't want to do all of this then put the model in a museum. It is very pretty! I wouldn't risk flying it with its current trim issues.

Once the wings are aligned then check your stab. With top wing at '0' the stab should be ~ positive 1 degree. If it isn't then welcome to the world of 'flight trim change with throttle change'. Though not ideal, computer radios make this 'yoked' management a simple fix. Engine thrust can(?) be altered to help. Good luck with your beautiful SE!

abufletcher

I should point out that the basic aerodynamics of the model design have been proven since another CDScaleDesigns SE5a has been flown by my friend, Teus, in the Netherlands. He reports that it is sensitive on the rudder but otherwise stable in the air.

So I'm not going to mess with any of the basic design incidences. All I want to do it correct any warps and/or asymmetries before flying it again. For example, the fact that my center-section isn't quite level from right to left is clearly my fault and not the design.

But your right, Michael, that I need to start from the ground up. Even though it's a pain in the neck to do these wires, it'll only take a couple of weeks at most...and I wouldn't be flying until probably late February at the earliest.

BobH

My Feedback: (2)

The Plus 5 degrees in both wings and stab is correct and mirror's the full scale plane. My Duncan Hutson SE5a won't turn at all using only airleron. You MUST turn using rudder..

abufletcher

Thanks for pointing that out, Bob. Yes, I'm getting the sense that the SE5a is definitely a RUDDER model. I didn't touch the rudder much during any of the flights so far, precisely because Teus had said it was sensitive on the rudder.

TFF

On my TF, I would not call mine sensitive, but dominant. It flies around like a heavy 3 channel trainer. Adding in ailerons like you would add in rudder like another. Although I fly mine uncoupled, I do have a mix that pretty much puts the rudder on the left stick barely moving the ailerons.

CafeenMan

Abu - what Camel is that?

abufletcher

Camel?

CafeenMan

Ah... didn't read it. It's a Snipe. So ok, what Snipe is it?

abufletcher

That would be my CDScaleDesigns 1/6 scale Sopwith Snipe. Sadly, the kits are no longer in production.

abufletcher

Basic question #1: What would be the effect in flight of more dihedral on the port wing(s) than on the starboard wing(s)?

...because with the wheels removed and the side winglets perfectly level spanwise (relative to the workbench), the lower port wingtip is indeed about 1cm higher than the starboard wingtip.

Basic question #2: What would be the effect in flight if the stabilizer wasn't level relative to the wings (but is level with the worbench and square with the rudder).

ARUP

An unlevel stab will create a lateral component of lift along with decreased vertical component. Just imagine the stab gradually rotating until vertical, like a rudder. Just think what it would do. Imagine half a 'V' tail. An asymmetrical dihedral will induce the same qualities. Plus, rudder and engine thrust line (except those with zero down and side thrust) will be altered.

abufletcher

I just checked the plans and they show 5.5 degrees of dihedral on the wings (top and bottom the same). Then I measured on the model using a cheap angle meter and it shows a bit over 5 degrees on the starboard side and closer to 8 degrees on the port side. So clearly the port (left) wing panels have too much dihedral. And that settles the question of whether the stab is out of alignment. It's not. The stab is level, it's the (left) wings that are off.

It's also the port side bottom wing that seems to have the "warp/erroneous washout" so I think I'll start by just redoing the rigging on the port side. I may also be able to resolve the problem with the unlevel center section without removing everything. We'll see.

Anyway, time to start cutting off some wires.

*****

I'm still trying to imagine what the asymmetrical dihedral would do in flight. Would greater port dihedral cause a strong pull to the left. Incidentally, I've checked the engine and there is absolutely no left thrust that I can see.

Previously someone asked about throws and differential. The throws are about typical for a 1/6 scale model with four (small) ailerons, i.e. about 2cm up and down. I thought I had differential set up but it doesn't look like it. But then I transferred the settings to a new Tx and maybe the differential settings got lost in the switch.

Michaelj2k

Isn't that what the free flighter's call "stab tilt"?

jack steward350

My Feedback: (7)

I really think you have it figured out. I do have a question: Would the off kilter bottom wing and equal length wing struts creat the twists in the wings being discused earlier? I think in the end you should have a very nice looking SE5 that you will enjoy flying for a long time. Always is worth the time to get things right.