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Old Apr 22, 2015, 02:42 AM
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Flight Test Program this morning
one change at a time
Back to the original setting for the mechanical linkage depth
If ok reduction of the volume of depth in P2
If ok setting new value of P and I in P1 profile
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Old Apr 22, 2015, 02:44 AM
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ooops
Google translation
Please replace depth by elevator
Sorry
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Old Apr 22, 2015, 05:14 AM
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The tests are OK
3 flights and a dozen transitions without problem
Changing the mechanical linkage of elevator to its original setting solved the problem
I set your new P and I values in P1 profile. Now the model is more stable and less tendency to oscillate even after hard correction but I must be still attentive in hover
I reduced the elevator volume in P2 profile from 40 to 36 it's better and still a bit sensitive but controllable without problem and I had no battery charged to continue.
A big thank you for your help. It's astonishing to see how our models look similar in their flight characteristics.
I don't want changing something until the next meeting in two weeks
After I plan to upgrade to version 1.1but i don't know what i can expect
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Old Apr 22, 2015, 05:18 AM
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CG just checked. It is 3mm (0.118 inch) forward the carbon rod
I did not recalibrate the gyros. level meter is perfectly centered
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Old Apr 22, 2015, 09:24 AM
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Quote:
Originally Posted by afterburner13 View Post
The tests are OK
3 flights and a dozen transitions without problem
Changing the mechanical linkage of elevator to its original setting solved the problem
I set your new P and I values in P1 profile. Now the model is more stable and less tendency to oscillate even after hard correction but I must be still attentive in hover
I reduced the elevator volume in P2 profile from 40 to 36 it's better and still a bit sensitive but controllable without problem and I had no battery charged to continue.
A big thank you for your help. It's astonishing to see how our models look similar in their flight characteristics.
I don't want changing something until the next meeting in two weeks
After I plan to upgrade to version 1.1but i don't know what i can expect
Congratulations on successful transitions. I think you may be the first.

You should feel free to tweak all parameters in small increments. For example, if the elevator is still too sensitive then change it from 36 to 33, and then to 30...

You can also play with P and I values in pitch to improve the hover. This is relatively easy, safe, and quick since you can even do it indoors.

You can also move your CG back slightly. The design intent was that it be on the spar, but that was just an initial target. Moving it back should improve hover stability. The larger than scale horizontal stabalizer should make it safe in FFF as well. I do not recommend sustained inverted flight though. Loops and Rolls are probably OK.

Ultimately it is a balance of characteristics. Now that you have it working you can fine tune it to your liking, or just leave it alone because you are already close to the best you can do.

The upgrade to V1.1 isn't really necessary for your purposes. I always recommend carefully testing things, but I expect you could just make the upgrade and fly the plane. No parameters should change, and nothing about the way the plane flies should change. V1.1 has additional features, but you aren't using them so from your point of view it is no change at all.

Make sure you get some good video. These complex aircraft tend not to last too long. Your previous video showed transitons at low altitude. That is fine for P1 to P1.n, but the transition to P2 should be at somewhat higher altitude, at least until you are very comfortable with doing them. Likewise the reverse transition from P2 to P1.n. You seem to be a good pilot, that helps.
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Old Apr 22, 2015, 09:43 PM
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I put the motor pods back together and started the putty sand fill process. I figure I might as well clean them up as much as possible before putting them back on the wing. There will still be some rough joints to clean up when I mount them but at least I can spray paint this much without having to mask the rest of the wing.
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Old Apr 24, 2015, 03:21 PM
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Putty-sand-fill complete. A quick cote of clear polyurethane, and then a light sanding. They still look ugly but looks can be deceiving. I test fitted the motor pods back on the wing where they fit fine.

The next step is a light cote of silver spray paint.

After that they can be put back on the wing. There will be some rough joints to putty-sand-fill after that, but mostly the motor pods will look better than new. I didn't do a particularly good job on them in the first place though.

I am thinking to do touch up paint on the wing with a foam brush, not direct spray from the can. That means spraying into a jar which is always messy. There is just too much detail to mask around for spray painting. The blending of the new and old paint may not be perfect, but nothing ever is...
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Old Apr 24, 2015, 06:28 PM
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Unfortunately I found some additional damage. The CF leading edge of the wing was broken at the plywood rib that supports the tilt linkage. I had to slice into the wing from below, open up a gap between the leading edge and the rib, insert a CF splice, glue and clamp the structure. All of this increases the cosmetic damage to the wing which will be difficult to hide. At least the wing should be back to full strength now.
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Old Apr 25, 2015, 11:39 PM
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This is what the motor pods look like after putty-sand-fill and spray painting. The flash actually makes them look worse than they really are. That and the jagged edges where they will soon be mounted on the wing.

After mounting them on the wing, it was necessary to putty-sand-fill the remaining joints and then touch up the silver paint with a stipple brush.

I made a disposable container from a small milk carton and then covered over all but a corner with tape. I sprayed into the corner opening using a plastic bag over my hand to keep my hand clean. There is always some backwash mist when doing this.

The picture shows the can without the normal spray head, but that is just because I had already removed the spray head and placed it in the jar of acetone where it will soak until the next time I need it. Using this technique the spray heads never clog, and it is not necessary to hold the can upside down and waste a lot of paint blowing out the internal draw tube.

I made the disposable stipple brush from a piece of scrap foam rubber and a piece of scrap depron. The important thing when using the stipple brush is to stipple, meaning to poke repeatedly, never brush, meaning never use sideways strokes. Stippling instead of brushing avoids brush strokes, meaning streaks in the paint texture. Repeated stippling eventually results in a "dry brush" which allows you to stipple around the edges of the fresh paint and blend it in with the old paint.
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Old Apr 26, 2015, 02:52 PM
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The wing is done. Not perfect, but ready for reassembly.
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Old Apr 27, 2015, 12:41 AM
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Good work Ran. Hope to see this fly soon.
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Old Apr 27, 2015, 10:31 PM
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Thanks Kasra. She's fully back and ready to fly. In some ways she is better than new, in others not so much. She has a new RX and satellite at least. I did some indoor hovering in the bedroom and she seems fine. Weather permitting she should fly this weekend. I have really got to stop crashing though. I don't know how much more she can take.
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Old Apr 28, 2015, 04:11 AM
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I guess you should build the Canadair CL-84 Dynavert and crash that instead
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Old Apr 28, 2015, 09:30 AM
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Quote:
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I guess you should build the Canadair CL-84 Dynavert and crash that instead
Parky has one of those. It flies fine, but is only capable of "snap transitions" meaning it has an abrubt change from hover to FFF and has no SFF mode. The FFF mode is also extremely limited by the FC so it can't even do a loop or a roll.

At some point Parky plans to convert it to OpenAero-VTOL and possibly cut the wing down to make it closer to scale. It remains to be seen whether the rather complex wing tilt mechanism is mechanically stable enough to be used in a SFF mode.
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Old May 02, 2015, 01:02 PM
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The XC-142 made 3 short test flights with full transitions this morning.

The 1st was near flawless.

I shifted the middle setting for the flap switch to P1.4 on my TX for the 2nd flight. It did OK but there was too much wing walking in SFF so I set it back to P1.3.

The 3rd flight was fine. I completed the flight and was doing some hover control testing, checking pitch and roll response, etc. Everything was fine, and then it went into a hard pitch oscillation and ended up upside down on the grass.

Fortunately, there was no damage, so I moved the battery back a bit to put more load on the tail rotor and did some more hover testing. This time it worked fine.

I suppose the lesson to be learned is that the XC-142 is a challenging model to fly. It has ways to bite you that come out of nowhere. It will probably become a bit of a hangar queen at this point.
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