New Products Flash Sale
Thread Tools
Old Aug 10, 2015, 12:52 PM
Electromagnetic is online now
Find More Posts by Electromagnetic
Ultra Violet
Electromagnetic's Avatar
Joined Feb 2013
5,046 Posts
Quote:
Originally Posted by gquiring View Post
I made a quick video of my Prelude flaps.

https://www.youtube.com/watch?v=b99dVGGx1Vk
That is exactly the play I am talking about. You must have a gap between your flap and wing also. I originally had asked about this because a very accomplished sailplane pilot at my club pointed it out and said it was not good to have this play. He said it is not good for maintaining proper flight modes such as Reflex, Cruise and Camber. BTW my post was not a case of complaining, rather it was making observations and finding the truth. Some people do not understand that concept.
Electromagnetic is online now Find More Posts by Electromagnetic
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 10, 2015, 01:15 PM
gquiring is offline
Find More Posts by gquiring
Sailplane Mafia
gquiring's Avatar
United States, SC, Summerville
Joined Jun 2001
2,313 Posts
Quote:
Originally Posted by Electromagnetic View Post
That is exactly the play I am talking about. You must have a gap between your flap and wing also. I originally had asked about this because a very accomplished sailplane pilot at my club pointed it out and said it was not good to have this play. He said it is not good for maintaining proper flight modes such as Reflex, Cruise and Camber. BTW my post was not a case of complaining, rather it was making observations and finding the truth. Some people do not understand that concept.
The tape is not the problem. If you want to reduce the slop, pull the horn and make a larger one. The problem is will you get enough servo travel to still drop them the full 90 degrees? You could also try pushing the hole more away from the hinge line. My first kit I glued them in the wrong way and it was slop city. I made a video of it. It's not a Top Model kit, it's an Elegant from Pelikan. This video will show how bad the slop is with a tiny horn on the hinge line.

Sailplane Flap is Sloppy (1 min 10 sec)
gquiring is offline Find More Posts by gquiring
Reply With Quote
Old Aug 10, 2015, 01:21 PM
electrich is online now
Find More Posts by electrich
V---- Thermal Generator
electrich's Avatar
United States, GA, Atlanta
Joined Feb 2011
5,461 Posts
You can try re-taping the hinge and reduce the gap to zero.

As for the previous talk about the Mystique, I have 2, as well as a Avia and Prelude. I prefer the Prelude best. My first Mystique had the wing fold in a thermal.
electrich is online now Find More Posts by electrich
Reply With Quote
Old Aug 10, 2015, 01:29 PM
Electromagnetic is online now
Find More Posts by Electromagnetic
Ultra Violet
Electromagnetic's Avatar
Joined Feb 2013
5,046 Posts
Quote:
Originally Posted by gquiring View Post
The tape is not the problem. If you want to reduce the slop, pull the horn and make a larger one. The problem is will you get enough servo travel to still drop them the full 90 degrees? You could also try pushing the hole more away from the hinge line. My first kit I glued them in the wrong way and it was slop city. I made a video of it. It's not a Top Model kit, it's an Elegant from Pelikan. This video will show how bad the slop is with a tiny horn on the hinge line.

https://www.youtube.com/watch?v=MT7Xyu8KUFw
I never said the tape was the problem, it is the gap between the flap and the wing.
Electromagnetic is online now Find More Posts by Electromagnetic
Reply With Quote
Old Aug 10, 2015, 01:30 PM
Electromagnetic is online now
Find More Posts by Electromagnetic
Ultra Violet
Electromagnetic's Avatar
Joined Feb 2013
5,046 Posts
Quote:
Originally Posted by electrich View Post
You can try re-taping the hinge and reduce the gap to zero.

As for the previous talk about the Mystique, I have 2, as well as a Avia and Prelude. I prefer the Prelude best. My first Mystique had the wing fold in a thermal.
I realized I needed the gap months ago when I was taping, it makes upward movement possible for Full House operation.
Electromagnetic is online now Find More Posts by Electromagnetic
Reply With Quote
Old Aug 10, 2015, 01:35 PM
gquiring is offline
Find More Posts by gquiring
Sailplane Mafia
gquiring's Avatar
United States, SC, Summerville
Joined Jun 2001
2,313 Posts
Quote:
Originally Posted by Electromagnetic View Post
I never said the tape was the problem, it is the gap between the flap and the wing.
That's what I was referring to the the gap because of the tape. The better sailplanes don't use taped hinges.
gquiring is offline Find More Posts by gquiring
Reply With Quote
Old Aug 10, 2015, 01:38 PM
Electromagnetic is online now
Find More Posts by Electromagnetic
Ultra Violet
Electromagnetic's Avatar
Joined Feb 2013
5,046 Posts
Quote:
Originally Posted by gquiring View Post
That's what I was referring to the the gap because of the tape. The better sailplanes don't use taped hinges.
You never mentioned the gap, I did.
Electromagnetic is online now Find More Posts by Electromagnetic
Reply With Quote
Old Aug 10, 2015, 03:23 PM
electrich is online now
Find More Posts by electrich
V---- Thermal Generator
electrich's Avatar
United States, GA, Atlanta
Joined Feb 2011
5,461 Posts
Quote:
Originally Posted by Electromagnetic View Post
I realized I needed the gap months ago when I was taping, it makes upward movement possible for Full House operation.
You can get away with "almost" zero gap on the flaps. You only need a few millimeters or so of up reflex in the flaps to achieve good results. Mine will really scoot with about 3 mm of up in the flaps and ailerons remaining normal. Aileron tape should be fine with a "little" gap.
electrich is online now Find More Posts by electrich
Reply With Quote
Old Aug 10, 2015, 03:40 PM
Electromagnetic is online now
Find More Posts by Electromagnetic
Ultra Violet
Electromagnetic's Avatar
Joined Feb 2013
5,046 Posts
Quote:
Originally Posted by electrich View Post
You can get away with "almost" zero gap on the flaps. You only need a few millimeters or so of up reflex in the flaps to achieve good results. Mine will really scoot with about 3 mm of up in the flaps and ailerons remaining normal. Aileron tape should be fine with a "little" gap.
I also wanted aileron to flap mix. I don't have much more uptravel than you. The ailerons have no play even though its gap is the same as the flaps. The different geometry has everything to do with it.
Electromagnetic is online now Find More Posts by Electromagnetic
Reply With Quote
Old Aug 10, 2015, 04:45 PM
donsinger1 is online now
Find More Posts by donsinger1
aka KF7DS
United States, OR, Portland
Joined Nov 2009
898 Posts
Quote:
Originally Posted by electrich View Post
You can try re-taping the hinge and reduce the gap to zero.

As for the previous talk about the Mystique, I have 2, as well as a Avia and Prelude. I prefer the Prelude best. My first Mystique had the wing fold in a thermal.
My newest Mystique RES has a substantially beefed up wing at the root, so hopefully that problem is less of a problem. Would be nice to see how they fly against a Prelude with two good pilots.
donsinger1 is online now Find More Posts by donsinger1
Reply With Quote
Old Aug 10, 2015, 06:40 PM
markschaffin is offline
Find More Posts by markschaffin
Registered User
United States, KS, Andover
Joined Oct 2005
550 Posts
The slop is coming from the pushrod being unable to resist the movement of the hole at the end of the horn.

On the aileron, the hole should be aligned with the hingeline, thus any movement of the control surface leads to a fore-aft motion of the horn tip (hole). Since the pushrod is at roughly a 90 degree angle to the horn (and the horn motion), it has no difficulty resisting the motion. No slop.

On the undeflected flap with the horn tip (hole) behind the hingeline, the predominant motion of the horn tip is not fore-aft, but up-down. Unfortunately, the pushrod is still at a 90 degree angle to the horn and can do little to prevent motion as the motion is in a direction 90 degrees to the pushrod. Slop. A longer horn is not going to change this.

Also keep in mind that the total aileron deflection is much less than the 90+ degrees the flap deflects. If you could somehow get the aileron to deflect 90 degrees, it would also have slop at that deflection since the pushrod can then do nothing to resist the motion of the horn.

Most DLGs are set up with flaperons with horns aligned with the hingeline. Any slop will lead to flutter on launch, so slop is not good. A difference is that most DLGs, at least mine, aren't set up to get 90 degrees of flap deflection. 40-50 degrees is plenty, not to imply 40-50 degrees is enough for the Prelude.

Another tact might be to go to a top drive, again, as a lot of DLGs do, where the flap horn is on top and the servo horn is on the bottom. The idea is to keep the horn/pushrod as close to 90 degrees as possible to reduce slop. Moving the horn to the top and AHEAD of the hingeline would tighten up the slop at 0 deflection or reflex. You may not get 90 degrees of deflection, but you might get enough. A little searching on the forums should turn up something like this, I'd expect. Found one... http://www.rcgroups.com/forums/showp...08&postcount=3

I don't see this as a design flaw, just a decision that was made to give more throw on the flap with a relatively simple set up. You could change the horn to be aligned with the hinge and get rid of the slop at zero deflection, but you will then get slop at 90 degrees flap (if you can get that much motion).

The question is where is the lack of slop more critical. I might argue it is more critical when making fine camber changes. Any slop at full deflection may be okay as long as the load forces both flaps to equal deflections.

I haven't kept up with the Mystique threads, but I have memories of reading about low flap deflections with the stock setup.
markschaffin is offline Find More Posts by markschaffin
Last edited by markschaffin; Aug 10, 2015 at 07:08 PM.
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion TopModel CZ Avia? MooSey-UK Electric Sailplanes 281 Nov 25, 2014 02:30 PM
Help! Modeller in the CZ <canopy for a Topmodel asw28 needed egall232 Scale Sailplanes 1 Dec 07, 2009 03:50 PM
Sold New, never flown Wilco/Tiger F5B Topmodel/CZ complete minus rx AndrewsJr Aircraft - Sailplanes (FS/W) 8 Nov 06, 2009 11:31 AM
Sold F5b Tiger/Wilco by Topmodel CZ bigslopegrin Aircraft - Sailplanes (FS/W) 1 Sep 22, 2009 07:28 PM