HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 09, 2012, 09:35 PM
I do this for fun!
Sunshine Coast, Australia
Joined Sep 2004
1,197 Posts
Question
LDS System?

Hi guys,

I'm looking at ordering a Freestyler 4 (I'm in Australia) and Franz has mentioned TUD's new LDS system which they are offering as an alternative to RDS. LDS stands for Linear Drive System.

I'm looking for info on the system and its pluses and minuses. All there is on the website is a photo which doesn't show the whole system.

All advice welcome.

Ken.
skyboyken is offline Find More Posts by skyboyken
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 10, 2012, 03:36 AM
F3B
satinet's Avatar
Warwickshire, England
Joined Sep 2006
5,520 Posts
photo?
satinet is online now Find More Posts by satinet
Reply With Quote
Old Jan 10, 2012, 03:46 AM
chetosmachine's Avatar
Madrid, Spain
Joined Sep 2004
1,102 Posts
Do you know the linkage of the Rotmilan? With a thick carbon arm, and a very short horn on the flap/aileron? Well, that's the same concept as the LDS.
New name, same thing.
chetosmachine is offline Find More Posts by chetosmachine
Reply With Quote
Old Jan 10, 2012, 05:53 AM
I do this for fun!
Sunshine Coast, Australia
Joined Sep 2004
1,197 Posts
Which system do you think will take the longest to develop slop, RDS or LDS?

and which do you think will be easiest to correct when it does?

I have to confess the reason I like old-fashioned linkages is that they are accessible and repairable/refurbishable. I really do wonder if either RDS or LDS is better in the long run.

Tom I don't have a photo and the one on TUD's website doesn't show enough to be worthwhile imho. If it did I wouldn't have to ask
skyboyken is offline Find More Posts by skyboyken
Reply With Quote
Old Jan 10, 2012, 06:05 AM
F3B
satinet's Avatar
Warwickshire, England
Joined Sep 2006
5,520 Posts
Ken,

to be honest the RDS system on my fs3 was really sloppy from the start. I know other people feel different about it, or didn't suffer the same problems, but I have to be honest. There was maybe 10mm of slop (if not more) on the flaps after a few months (kind of soft/spongy feel).

If you put a few % of travel on the servos, say for reflex, it didn't even show up on the control surface. Centring on the bench was also very bad. I'm sure not helped by using graupner ds3288 servos, which IMHO are not the world's most accurate. Other people who say the model would back me up I'm sure. If fairness the model didn't fly like it was double centring but it was virtually impossible to set up relfex, without trial and error.

I'm not saying that freestylers are no good, but I would rather have a normal linkage. Unless you are really really good I think the drag difference is kind of irrelevant (I'm not). Anyway I think control surface that move accurately would outweigh the benefits of RDS drag reduction.

Personally I don't think LDS will develop slop that quickly. If it is like the rotmilan you will get wear as the rod rubs in the carbon (which is replaceable anyway), but surely that will be pretty slow?
RDS wears out the wing skin on the model and creates more flex, IMHO.

Better to tie the servo to both wing skin surfaces, use a bearing and have an internal (LDS) system if you must. Again IMHO.

I don't think I would call the rotmilan system an "unconventional" linkage - the geometry and principle is the same really. Correct me if I am wrong.

My current fs3 is normal linakges - I am using MKS servos with Fu bearings when I get round to building it. Personally I wouldn't buy another freestyler with RDS although I would definitely buy another freestyler as they obviously fly great and are nice quality with nice looks, good service from Tud etc

I would go for the LDS system or conventional linkage if it were my money.

T
satinet is online now Find More Posts by satinet
Reply With Quote
Old Jan 10, 2012, 09:24 AM
Registered User
Joined Jan 2010
185 Posts
I agree with Tom.
The Rotmilan linkage looks the nuts, and would seem to offer the best "minimal" slope solution.
The offset crank idea means a steady supply of torque and a consistant drive.

The Freestyler RDS system is not the best.
I seem to think they use the hollenbeck system.
I have this installed in my Extasy, and its very similar to how Tom's didnt work on his FS3.
Very sloppy and a few mm of movement in any offset position.

I did some fettling with my Extasy to sort the double centering.
It seems from me that the frame used to house the bearing is the only bit thats bonded to the wing skin.
The servo screws into the frame and thats it.
The skin then flexes and causes very bad slop in the flap or aileron. (See picture)


On the extasy I took some of Mr Fu's advice and tied in the servo to the upper and lower skins.
While this didnt completey readicate the slop, it greatly reduced the amount and I was the able to induce camber changing to flaps and ailerons.

You have to be careful that you dont glue the lot together, but using some FR4 board I bridged the gap between the servo holes and used a dollop of bathroom sealent on the FR4 board against the servo and expoy and micro-balloons to bond the FR4 to the wing skin.

Jon
ceres-syd is offline Find More Posts by ceres-syd
Reply With Quote
Old Jan 10, 2012, 10:09 AM
Registered User
Brandon's Avatar
Riverside, California, United States
Joined Feb 2004
1,505 Posts
Here are the pictures of the LDS system that are posted on the German site of TUDM. They are not posted on the english site, at least I could not find them....

B
Brandon is offline Find More Posts by Brandon
Reply With Quote
Old Jan 10, 2012, 10:10 AM
Registered User
Brandon's Avatar
Riverside, California, United States
Joined Feb 2004
1,505 Posts
I also have to say, I am not a big fan of the 378 servo with regards to slop.....My new FS4 has the Hollenbeck frames with MKS and there is no slop.....
Brandon is offline Find More Posts by Brandon
Reply With Quote
Old Jan 10, 2012, 10:54 AM
F3B
satinet's Avatar
Warwickshire, England
Joined Sep 2006
5,520 Posts
well they are pretty pointless now MKS are around. I would not buy them any more.

The LDS looks good. Don't give in to temptation...
satinet is online now Find More Posts by satinet
Reply With Quote
Old Jan 10, 2012, 12:27 PM
Biting ankles since '53
No Pants Island
Joined Feb 2007
2,944 Posts
Looks like Jaro Muller's FISD system

http://www.skipmillermodels.com/Espadita_p/espadita.htm
mr_editor is offline Find More Posts by mr_editor
Reply With Quote
Old Jan 10, 2012, 12:45 PM
F3B
satinet's Avatar
Warwickshire, England
Joined Sep 2006
5,520 Posts
the muller system is also a system of mounting the servos. The Freestyler/Rotmilan system uses conventional servo mounting.
satinet is online now Find More Posts by satinet
Reply With Quote
Old Jan 10, 2012, 03:11 PM
Registered User
Slovakia
Joined Nov 2009
58 Posts
LSD , Guys there is nothing new, I am using this system in Aspire for over 3 years

http://www.rcgroups.com/forums/showthread.php?t=1239669
http://www.rcgroups.com/forums/showthread.php?t=1239669
fly-up85 is offline Find More Posts by fly-up85
Reply With Quote
Old Jan 10, 2012, 03:21 PM
Registered User
Leicestershire
Joined Sep 2006
1,184 Posts
Cool! I think that LSD is the way to go as well - opens your eyes to all sorts of new perspectives! I might have used LSD about 20 years ago, but for some reason I can't really remember now

Seriously though, that system looks to eliminate the trad probs with regular linkages with non of the RDS issues whilst streamlining beautifully. Narce.

Z
Zimodile is offline Find More Posts by Zimodile
Reply With Quote
Old Jan 10, 2012, 04:40 PM
Team USA F3F Member
ttraver's Avatar
USA, CA, Carlsbad
Joined Feb 2011
1,141 Posts
Tom,

10mm of slop in the RDS system in your freestyler?????

Something was not right then, cause there's no way that you should have that kind of slop with the system. Even with the Hollenbeck system. There must have been something not right with the pocket or the diameter of the wiper or where the knuckle ended up over the hinge or something, cause that just doesn't seem right...

I'm not trying to insult you or your building or anything, I'm just offering my 2 cents on seeing lots of RDS installations on other planes as well as my own...

Tim
ttraver is offline Find More Posts by ttraver
RCG Plus Member
Reply With Quote
Old Jan 11, 2012, 01:53 AM
Registered User
Joined Jan 2010
185 Posts
Tim,
Like Tom the hollenbeck installation was done at the factory, all that had to be done was fit the servo (Same for my extasy).
In my mind there is only one RDS system that works (I have it on 3 of my models) all by one manufacturer.
Now if TUD started to use the baudis system then it would be truly outstanding.
J
ceres-syd is offline Find More Posts by ceres-syd
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question LDS JetMach 44 EDF Conversion? Brill 1 Electric Ducted Fan Jet Talk 8 Mar 27, 2010 02:43 PM
Discussion Prop 8: California gay marriage fight divides LDS faithful 7rider Life, The Universe, and Politics 100 Oct 28, 2008 04:22 PM
Discussion LDS (Mormon) Timpanogus Temple, American Fork, Utah JONBOYLEMON Aerial Photography 2 Oct 09, 2007 11:15 AM
Discussion Are you LDS and do you fly on Sunday.. fly4fun Life, The Universe, and Politics 21 Jan 02, 2007 07:55 AM
Discussion The new LDS Temple California Condor Aerial Photography 16 Aug 20, 2006 07:45 PM