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Old Sep 15, 2012, 04:02 PM
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Rudder will induce roll in nearly all airplanes. With my (Slightly bigger, heavier) Tomcat having only elevons it becomes even more coupled. My Tomcat with the wings out has a very anemic roll rate, rudders would be great to have at that point. With the wings back it behaves fine with plenty of roll authority. So play around with those rudders, reducing the travel and see what amount of each it takes to fly good.
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Old Sep 16, 2012, 06:36 AM
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Cheers guys, I will try to turn down the throws and see how it goes. Next week! =)
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Old Sep 18, 2012, 02:59 PM
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Flew the Tomcat again lasst Saturday. The new wing servo works better but it still binds and needs a little negative G for support. With the wing extended the roll rate is scary slow and at times depending on power not there at all. But with the wings back is handles nicely. It lands just as slow with wings out or back so I just land with them back to give me better roll control.

I cut out the Shumate F-18 and will start the build this week. I'll post a photo here and on the F-18 forum.

Later.
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Old Sep 18, 2012, 06:39 PM
Row 0, Seat A
G550Ted's Avatar
Savannah, GA
Joined Jan 2008
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Quote:
Originally Posted by AlfaXray1 View Post
Flew the Tomcat again lasst Saturday. The new wing servo works better but it still binds and needs a little negative G for support. With the wing extended the roll rate is scary slow and at times depending on power not there at all. But with the wings back is handles nicely. It lands just as slow with wings out or back so I just land with them back to give me better roll control.

I cut out the Shumate F-18 and will start the build this week. I'll post a photo here and on the F-18 forum.

Later.
AX1,

You may want to check the control throws on your stabs. With the recommended (or set 'em how you like) throws this model has a very scale roll rate with the wings forward, a sporting quick rate at mid sweep and downright scary with the wings at full sweep!

Ted
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Old Sep 18, 2012, 09:09 PM
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I'm using a DX-8 I think the throws are stock 100% stuff, but I notice that if I give full up elevator they both move about 1/2 of the available movement, and then the Aileron will fill that out to full movement. Aileron does the same way. But is there a way to set Full Elevator and Aileron without it trying to over move the surfaces? I would like 100% movement on Elevator and aileron but not colliding with the rudders.
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Old Sep 19, 2012, 02:21 AM
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alpea 41's Avatar
United States, CA, Chino
Joined Oct 2007
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End point travels in elevon or delta wing function are restricked on some Spektrum radios to avoid over travel when elevator and roll are both commanded to the limit of the gymbal. i E. When the stick is pushed to the extreme corner of the gymbal ...
There is a way to set End Point Adjustment over riding these limits , and I think you do it by using Dual Rate percentages menu instead of the EPA menu. Anybody agree? Or know different ,don't hesitate to correct me.
Just know that when setting up Dual Rate Percentages you have to hold the stick to the right while you set right elevon then to the left for the other direction . Same for the up and down

And like you said try not to deflect your elevons into your rudders
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Old Sep 19, 2012, 06:31 AM
Row 0, Seat A
G550Ted's Avatar
Savannah, GA
Joined Jan 2008
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Quote:
Originally Posted by AlfaXray1 View Post
I'm using a DX-8 I think the throws are stock 100% stuff, but I notice that if I give full up elevator they both move about 1/2 of the available movement, and then the Aileron will fill that out to full movement. Aileron does the same way. But is there a way to set Full Elevator and Aileron without it trying to over move the surfaces? I would like 100% movement on Elevator and aileron but not colliding with the rudders.
I don't know anything about a DX-8 so I can't help there, sorry. Your other option is to change the mechanical linkage setup. To achieve increased throws on the surfaces you need to move the push rod attach point on the servo arm outward and/or the attach point on the control horn inward. Following that you can fine tune the limits needed in your radio's setup.

HTH,

Ted
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Old Sep 19, 2012, 03:19 PM
ham
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Denmark, Capital Region of Denmark, Dragør
Joined Mar 2007
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I had the same problem on my scratchbuild raptor with the DX6i. I found out that I could set the mix 1 to elev-->elev and mix 2 to ail-->ail almost to max on both. Don't have the transmitter right here and don't remember exactly, but play around with it until it's right and remember to check it in both directioms up/down left/right.
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Old Sep 19, 2012, 10:54 PM
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alpea 41's Avatar
United States, CA, Chino
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Yeah when I was dissapointed with the control end points on a elevon wing type it was also on a DX6I
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Old Sep 20, 2012, 02:47 PM
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Joined Mar 2006
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Quote:
Originally Posted by ham View Post
I had the same problem on my scratchbuild raptor with the DX6i. I found out that I could set the mix 1 to elev-->elev and mix 2 to ail-->ail almost to max on both. Don't have the transmitter right here and don't remember exactly, but play around with it until it's right and remember to check it in both directioms up/down left/right.
Yes that is the "fix" for the DX6i to get the elevons to work correctly.
And it works on the DX8 too.
Just mix elev to elev and ail to ail for about the full 100%! Worked like a charm when I still had the 6i...l

I fly my Tomcat with a 12X, and the sweep controls the flightmode too, so when the sweep is at 68* (full aft) the roll rate is limited (due to a lower rate on the elevons). It still rolls insanely fast, but I have much more expo on that setting, so it stays nicely controllable.
If you don't have flightmodes on your radio I strongly suggest you put hi and lo rates on, with the low rate setting with less deflection and much more expo as well, and use that when you sweep the wings aft.

What an awesome design Mike made for us, eh!
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Old Sep 20, 2012, 09:23 PM
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I'll try the mixs on my DX8 and let you know how it works. Thanks for the tips.
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Old Sep 23, 2012, 05:08 AM
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Singapore, Singapore
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Welp, knife edges are still pretty hard.

I dialled the throws down to 20%. Still nope. On yaw tests, the model starts yawing, yawing, then BAM it's rolling in the sky. The transition is quick and comes without any warning. The induced roll is so violent that even with the wings out and the movement set at 30%, I can roll the MDC F-14 faster than I can roll it with my ailerons with the wings at the halfway sweep position.

I will try some mixing, Bonedoc has a KE mixing tutorial that I will check out. It doesn't help that I am still a total noob and have to concentrate to keep my wings level and my attitude changes smooth. More updates in the rudder adventures to come.

Incidentally, if anyone has tried putting rudders on this bird, can I please get some tips .
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Old Sep 24, 2012, 10:00 PM
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United States, CA, Fremont
Joined May 2012
309 Posts
I'm planning on building one with :
Some $T Foam with paper
No carbon support
1 HS-65HB
http://www.hobbyking.com/hobbyking/s...g_0_14sec.html
2 HXT900
http://www.hobbyking.com/hobbyking/s...cro_Servo.html
7x4 prop
http://www.hobbyking.com/hobbyking/s...2pcs_set_.html
RX
http://www.hobbyking.com/hobbyking/s...Sat_Port_.html
30A Turnigy ESC
http://www.hobbyking.com/hobbyking/s...ontroller.html
EMAXX CF2812
http://www.hobbyking.com/hobbyking/s...er_1534kv.html
Turnigy nano-tech 1300
http://www.hobbyking.com/hobbyking/s...Lipo_Pack.html

Possible? This is similar to my f22 scratchbuild designed by dekan. Stuff preferably from HK, so I can just shop at one place :P.

~Nick
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Old Sep 24, 2012, 10:05 PM
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United States, CA, Fremont
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309 Posts
Also, is there a manual for this scratchbuild? I read somewhere that Maybz was working on one.
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Old Sep 24, 2012, 10:10 PM
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United States, AZ, Chandler
Joined Feb 2012
117 Posts
Quote:
Originally Posted by rcmaniac098202 View Post
Also, is there a manual for this scratchbuild? I read somewhere that Maybz was working on one.
Check out page 34 for build pics and details
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