Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Jan 17, 2013, 06:49 PM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Done! The servos are mounted and are rock solid. Ailerons are looking good!

Colored the foam with a sharpie magic marker and it all blended together nicely into the striping on the wing underside. Many kudos to my lovely wife for her help with the fiddly bits!

Click to view video
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 01, 2013, 08:42 PM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Finally got a chance to test fly the Decathlon with the ailerons this afternoon. Whew! Needs more adjusment.

Click to view video.
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Old Feb 01, 2013, 10:48 PM
Registered User
seeingeyegod's Avatar
United States, OR, Portland
Joined Jan 2008
1,787 Posts
Thanks for the video. Were you already using some differential aileron or none? Are you also inputting any rudder in the turns at this point or just yanking and banking?
seeingeyegod is offline Find More Posts by seeingeyegod
Reply With Quote
Old Feb 02, 2013, 07:37 AM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Quote:
Originally Posted by seeingeyegod View Post
Thanks for the video. Were you already using some differential aileron or none? Are you also inputting any rudder in the turns at this point or just yanking and banking?
I did have a little mechanical differential set up from the get-go. But, mostly I was fighting the wind and the out of trim condition of the plane. Not only had I installed the ailerons, but I'd moved the control linkage on the rudder to the outermost hole so that had been adjusted too. And my tailwheel wasn't lined up right after that, so takeoffs were interesting as well.

On the first flight I had so little aileron control authority that the wing was barely banking over. I was using aileron only since I'd expected a lot more control. Once I finally got the plane up to about 75 feet and trimmed a little better, I brought it down for adjusting. Total flight time was maybe a minute. Seemed a lot longer, though!

While sitting in the truck waiting for the lipo to recharge (I only have one for this plane right now) I got to thinking about the flight and at first thought that it acted tail heavy. Then I figured that I needed to do more of a coordinated turn with rudder and finally realized... DUH! Serious adverse yaw.

On the second flight I'd adjusted as much mechanical differential that I could muster while at the field, but it clearly wasn't enough. And yeah, I still had plenty of "down" aileron compared to the "up" side.

Today I'm going to try some longer servo arms to help with the differential and also set in some transmitter differential if I can with my FS-CT6B. Have to investigate that option.

Will be going out flying this afternoon... gonna be 68 degrees with no wind and plenty of sunshine. I'll take the Decathlon with me and try again. Results from today's test will be important. I need to get the differential worked out before I complete my Dick's Dream build and fly that plane with its barn door ailerons.

The good news is that the aileron servos stayed rock solid in their places. Whew!
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Old Feb 02, 2013, 08:51 AM
Registered User
Tennessee
Joined Sep 2003
2,308 Posts
I always mount my servos with screws. I have never had a servo fail that was easy to replace and all my servo failures have been with servos glued in the wing. I believe it has something to do with Murphy's law.
ChuckA is online now Find More Posts by ChuckA
Reply With Quote
Old Feb 02, 2013, 08:58 AM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Quote:
Originally Posted by seeingeyegod View Post
Thanks for the video. Were you already using some differential aileron or none? Are you also inputting any rudder in the turns at this point or just yanking and banking?
BTW - here's how the plane flew with just rudder, elevator and throttle.

Click to view video
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Old Feb 02, 2013, 09:00 AM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Quote:
Originally Posted by ChuckA View Post
I always mount my servos with screws. I have never had a servo fail that was easy to replace and all my servo failures have been with servos glued in the wing. I believe it has something to do with Murphy's law.
So I guess you didn't read the whole thread, eh?
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Old Feb 02, 2013, 01:17 PM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Okay, I now have 50% more up aileron than down. Going flying shortly and will report back with results later tonight.

Click to view video
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Old Feb 02, 2013, 01:37 PM
Registered User
seeingeyegod's Avatar
United States, OR, Portland
Joined Jan 2008
1,787 Posts
This plane was designed to fly well without ailerons so it might be difficult to get them to work well, interested to see if you can get it to though. I also flew mine once when it was extremely tail heavy after a repair and barely managed to get it down in one piece. I assume you are checking the CG against where it should be?

Interesting to see you got yours to spin with just RAE control, I never managed to do that!
seeingeyegod is offline Find More Posts by seeingeyegod
Reply With Quote
Old Feb 03, 2013, 11:06 AM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Quote:
Originally Posted by seeingeyegod View Post
This plane was designed to fly well without ailerons so it might be difficult to get them to work well, interested to see if you can get it to though. I also flew mine once when it was extremely tail heavy after a repair and barely managed to get it down in one piece. I assume you are checking the CG against where it should be?

Interesting to see you got yours to spin with just RAE control, I never managed to do that!
You're absolutely right... and after concluding this experiment, I've decided to return the plane back to its original 3 channel configuration. Bummed me out, too. I'd been hoping that it could become a nice 4 channel test bed for future radios and sundry equipment. But alas, 'twas not meant to be.

The CG was spot on... maybe even a smidge noseheavy. Perfect. As can be seen in the photo below, the servo arms and linkage were maxed out for as much differential as could be had. The differential did help, but the plane still needed coordinated turns in order to change direction. And it also lost altitude quickly when turning. Using aileron only didn't work well and once rudder was added, the dihedral really kicked the plane over quickly. Adding in up elevator to keep it level caused the plane to feel like it was going to just fall out of the sky.

The plane was already a little underpowered and slow and with 3 channels I normally had to climb for a long time, do some aerobatics, then wait again while climbing back up. With the ailerons, much of the airspeed was bled off with each turn, delaying the climb. In the 3 channel configuration, it's a great little fun flyer. With 4 channels it became something that required full attention at all times and was a little nerve wracking. Unsatisfactory.

While it is possible to remove the dihedral to continue experimentation with the ailerons, I just don't see it as being worthwhile in this instance. This little Decathlon has an undercambered airfoil while the full scale aircraft uses a very nice semi-symmetrical wing in order to be aerobatic.

If the wing was cut in order to remove the dihedral, a strong spar would need to be added and that's just going to hang out in the airflow, increasing drag further. And a stronger motor would really be needed in order to get the performance desired. Again, not worth it in my eyes.

So today I'm going to glue the end points of the ailerons with hot glue and tape the upper and lower gaps to seal things up and strip off the servos and linkages. Thus I will return the plane to it's bouncy little self.

Ah well, it was educational anyway.

Click to view video
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Old Feb 03, 2013, 01:49 PM
Registered User
seeingeyegod's Avatar
United States, OR, Portland
Joined Jan 2008
1,787 Posts
That didn't look too bad, at least you can do aileron rolls How did you film that by the way, did you have a camera person filming for you? Good job keeping the plane in frame.
seeingeyegod is offline Find More Posts by seeingeyegod
Reply With Quote
Old Feb 03, 2013, 03:18 PM
20+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,209 Posts
Quote:
Originally Posted by seeingeyegod View Post
That didn't look too bad, at least you can do aileron rolls How did you film that by the way, did you have a camera person filming for you? Good job keeping the plane in frame.
I was working my tail off in order to keep that plane flying right as shown in the video. My lovely bride did the video work with my ordinary digital camera. She's become quite good at it over the last few times out.

BTW - my Decathlon is now back to its regular configuration with rudder, elevator and throttle. I stripped the aileron servos and stuff and put it back into my stock.

And those servos never would have come off without a prybar or knife! The technique I used to secure them to the wing was very effective and I'll use it again in the future if I have such a need.
BigIron357 is offline Find More Posts by BigIron357
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question Best way to mount servos in foam? dedStik Foamies (Scratchbuilt) 4 Apr 12, 2012 04:46 PM
Best way to secure TM battery? cfossa Parkflyers 4 May 20, 2002 09:17 PM
What's the best way to secure MP Jet Gearbox and a 280 motor? twng Beginner Training Area (Aircraft-Electric) 2 Mar 05, 2002 08:35 AM
Best way to secure servos in a Zagi? Skid Foamies (Kits) 15 Jun 05, 2001 08:03 AM