Don't get too carriedaway. I'd start with maybe 1/16" of shim under the lower bolts and see where that gets you.

TF

Alright.. thanks Tom..

I leave tonight.. my CF tube will arrive Friday and in 2 Sundays I will take her to the field and a pocket full of washers


Will keep you guys posted!

Below is a link that has very good information about trimming, thrust angles, etc. from Peter Goldsmith. His method for getting the correct thrust angle is simple to duplicate. Thought I'd post it in case it's of use to you.

Dan

http://www.mini-iac.com/Portals/57ad...20trimming.pdf

Well I got a couple more flights and the Cap yesterday. She flys very well and does harriers great.

I have my CG sorted out.. I ended up getting a CF stab tube and I was still border line at the 4" mark with my CF spinner so I went and put on my Al. one for now. Right now it sits in the middle of the range.

I have the up and down thrust correct finally.. still needs more right thrust. Hovering wise it seems pretty stable.

I do still have one issue that is bothering me and that is teh fact that it still needs a fair amount of down to fly. Orig. flying at half throttle and chopping it the cap would jump up.. now it does a smooth glide path and when I get on the throttle it just moves forward.

I am sure it's not perfected yet because the flying with down el. is gong to change things when I get taht fixed.. but it's a lot better than before and the massive coupling started to go away. I mixed rudder to el. so that the el. was neutral in KE and the coupling is basically gone.. so I know when I get the last of my problems fixed I should have a great flying plane.

Going to check incidence today.. safe to assume it's 0 and 0 ?

not safe on any arf, but mine was on so kudos to that guy. i miss flying the cap i haven't gotten out since the 2nd week in december.

I think he mean is it safe to assume that 0-0 is the proper incidence.

Yes 0-0.

TF

Yep that's what I meant.. sorry for the confusion

Well I am now officially at a loss... incidence is 0-0.. I mean it's def. hard to tell 100% perfect but it's within .5 degree for sure.

So now I am not sure what to look for. When flying it..if you look at the counter balances there is a good 1/16" showing for down el just to fly level. This translates into major coupling for KE. While you can mix it out I would def. like to try and solve this issue. I havent had a plane need this much trim to fly level before.

What I can tell you is because of the amount of thrust correction needed the spinner back plate is not 1/8" higher than it should be. I have every intention of correcting this but I was trying to get the trust correct before moving the motor down again. I already moved it down once but needed more up thrust yesterday. Up / Down thrust it seems great right now.

Could the engine being 1/8" higher than it should cause that much down el. needed to fly level?

Thanks for the input

It sounds like it's just tail heavy, that's why you carry down elevator trim.

Just for testing add several ounces (4-6, maybe more?) in front to move the CG forward 1/2", I'll bet that neutralizes theproblem.

TF

That's what I thought so I added my Al. spinner without a lightened backplate. It requires a lot more down inverted then I would like and doesn't even really do a nice waterfall.

Right now if I pick it up right side up it balances level right before 3.75" from the leading edge of the wing.

yeah i also noticed that i would put the cg back further but i can't because it will climb like crazy when i roll invt.... so i ended up putting my cg back to the point where it wouldn't climb inverted anymore... this location isn't as far back as i'd like for parachutes and waterfalls etc but its close to good enough. so i just enjoy the stuff the cap does well and do my best to enjoy the stuff it does ok. the more stick time you get on it, the more you like it

For CG, you might want to calculate the MAC (mean aerodynamic chord). According to Dave Patrick, for monoplanes, most “conventional� designs fly best when balanced 30% - 33% of MAC. (Biplanes are about 25% - 30% of MAC). Here’s how he says to do it:

- Measure the chord of the wing at the root, e.g., let’s say it’s 8 inches.
- Measure the chord of the wing at the tip, e.g., let’s say it’s 6 inches.
- Determine what percentage of MAC you want to find, e.g., let’s say it’s 33%. We would find that:
- 33% of an 8-inch root chord = 2.64 inches. (8� x .33 = 2.64�)
- 33% of a 6-inch tip chord = 1.98 inches. (6� x .33 = 1.98�)
- Next, measure back from the leading edge at the root chord 2.64 inches and back from the leading edge at the tip 1.98 inches. A line between the two reference points is the “average 33% line.�
- Cut the “average 33% line� in half; at the dividing point, you will have an approximation of the 33% MAC balancing point. Check balance at the dividing point.

According to Patrick: this system works well on most straight leading- and training-edge wings; ignore a faired or shaped tip, it’s insignificant; ignore any wing fairing at the fuselage.

You said that your balance is currently right about 3.75�. To be in the 30% - 33% range, if measuring just at the wingtip, you need to have a tip chord measurement of 12.5� (3.75�=.3(x); 3.75�/.3=12.5�) to be at 30% of MAC. To be at 33%, you need a tip chord measurement of 11.36� (3.75�=.33(x); 3.75�/.33=11.36�).

Dan

thats all great and such but in the end its where it "feels right" that matters most to me

aegis: Thanks for the indepth response.. I also saved the link you posted on the other page.. thanks!

Root is 20.75" and wing tip is 11.25" I just did it quickly with a straight edge to check. It appears I am in the correct area.

erikpmort: The thing is that even with the down el. to fly level right now when I go in verted it still requires a lot more down to fly level. I would have thoght with the amount of down it requires for upright level flight it would have climbed or atleast not needed much to fly level inverted.

I have really ruled out being tailheavy because I ended up adding more low rate el. because it felt a little soft for my tastes. You really have to push it to flatten out in an inverted flatspin and it sometimes feels like it's too nose heavy to even get it into one.


Incidence wise let's say my reading wasn't 100% accurate.. keep in mind I am thnk it is perfect but allowing for .5 diference. If the difference is actually 1 degree is that going to have this much effect on how it flies? I was under the impression .5 or 1 degree was acceptable? I am going to do it again just to make sure I am right but I did check it 3 times lastmight. and hit between 0 - 0 and 0 - .5

Thanks for the imput guys...

That's true with many things, such as throws, props, etc., but it's quicker to get where it feels right if you are starting from a close baseline. The 30% - 33% isn't a hard-and-fast "rule;" it does provide a very good starting point though and is better/quicker than arbitrarily moving the CG hoping to get it close. It also helps to remove a possible variable (CG) when trying to figure out why something is happening such as having to carry a lot of trim. Unless the plane wasn't designed within "conventional" parameters, if the CG is in this range and you are still having to carry a lot of trim, there's an issue somewhere else.

Sure. It sounds like it may help rule out a CG issue.

Using the trimming methods outlined by Peter Goldsmith takes a while, but when finished a plane flies so much better.

Dan

Well unfortunately I havent had the weather to really fly this guy again since I made some more thrust adjustments and readjusted the CG. I moved my engine back so it's perfectly centered now and I am at what I am hoping to be the perfect CG now *crosses fingers*

I did actually break down and buy a scale this week so I just weighed my Cap.. 17 pounds 3oz. CF spinner, stab tube, wingtube, 3 NoBS packs, 3 switches, stock wheels, all DuBro hardware. Was able to get my gear setup well inside so I could go back to the CF spinner.

Come on weather.. just break 40 for me

You're in Delaware. Relax. You have time.

TF

Sinergy,Tom,

Can you give me all the details of your thrust, cg and other equipment placement like throttle and choke servo, batts etc.

I recently bought a used 85" Cap with a DA-50 and promptly gutted it as the build was sub par IMHO. When I got it, the throttle and choke servos were mounted forward of the first former(in the bottom of the motor box) and it has a good bit of lead stuffed behind the firewall. It also has a C/F spinner which I'd like to keep if possible for the bling factor of course.

It also had a bunch of washers to give right and up thrust, but I don't remember how many.

Thanks

All,
I'm sure this thread is dead but I just recently acquired an 85" Cap 232 and I too encountered the above triming issues. I purposely installed a known heavy powerful motor to A - test this motor and B- to have a good throw down plane for weekend hacking around.
I think Tom is correct you do need to plan and work a little harder to get the plane trimed like you want. I see no problems to get the plane to do what I need to do.

3W-60K swings a 24x8 TF prop at 6500 or 24x10 Bunny @ 6000
Bisson DA50 Side mount muffler - test at our field 96DB at 20 feet
RCXEL single ignition replace the old 3W ignition, set at 28 degree BTDC.
Dual A123 2400 MAH batteries
2ea 94851 New Airtronics sport digitals on elevators
2ea 94162z analogs on ailerons
2ea 94162z on rudder
Hitech 225 MG on throttle
Radio Airtronics Stylus 2.4 module on FHSS1 8 channel 92824 2.4Ghz receiver.

This ship weighs 18 lbs solid and I have no added weight to balance
I am at the 4" CG mark at the wing tip per instructions.


JDS

finally got the cowl painted.

.