HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 08, 2005, 02:31 PM
Mike R. I find sink.
West Covina, California
Joined Aug 2004
395 Posts
So, how do YOU trim your plane?

Getting back into flying after a five year hiatus, I realize I don't have a very good sense of whether or not my plane is trimmed correctly. Is it nose heavy? Tail heavy? Is the camber or reflex doing what I want it to do?

So, any tips or tricks on how to trim?
Wildewinds is offline Find More Posts by Wildewinds
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 08, 2005, 03:53 PM
Registered User
Williamsburg, VA
Joined Apr 2004
227 Posts
Trim resources

A volatile topic to be sure, certain to generate a number of diverse opinions... Nevertheless, two informative articles that are well-written can be found here:

http://www.badger.rchomepage.com/trim.html

and here:

http://www.gliders.dk/triming_and_se...der_wi_eng.htm

Credit to Warren Man-Son Hing and Erik Dahl Christensen respectively; hopefully they do not object to me providing these links.

r/
Dave
D_Ryan is offline Find More Posts by D_Ryan
Reply With Quote
Old Nov 08, 2005, 03:56 PM
Think Thermals!!!!
SoCalGliderFlyr's Avatar
Costa Mesa, California
Joined Mar 2004
2,964 Posts
I keep taking nose weight out till it flys backwards then add a half ounce.
SoCalGliderFlyr is offline Find More Posts by SoCalGliderFlyr
Reply With Quote
Old Nov 08, 2005, 06:03 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
10,886 Posts
For basic CG placement I like dive testing. Tune the CG and resulting elevator trim until the model just slooooooooowly pulls out of a dive. That's about 3 steps before it starts flying backwards! ! ! ! !

Good one Socal... LOL
BMatthews is offline Find More Posts by BMatthews
Reply With Quote
Old Nov 08, 2005, 06:11 PM
Think Thermals!!!!
SoCalGliderFlyr's Avatar
Costa Mesa, California
Joined Mar 2004
2,964 Posts


It's the truth! Well, those that have flown my planes say it is.
SoCalGliderFlyr is offline Find More Posts by SoCalGliderFlyr
Reply With Quote
Old Nov 08, 2005, 10:34 PM
aka ben wilson
thelocust's Avatar
louisville, ky, usa
Joined Mar 2001
832 Posts
...

1. Ensure all physical trims on the ground are in good order. Elevator flat (full-flying ones are tricky), rudder straight, ailerons and flaps good.

2. Fly it fast - this will give you a good indication of any trim issues. This also includes doing a dive-test which will get you up to that high speed. If the plane pulls up when speeding up, you are nose-heavy.

3. Fly it slow -- see what thermal camber and landing flaps do to it while you have altitude.

4. For a poly plane, see how long it takes for you to initiate a turn with the rudder. This can give a good indication of not only rudder throw but proper washout/in on your tips.

This is assuming that your wing and tail are square and that your linkages are tight.

That's what I've done on handlaunch, 2-meter and unlimited ships. That said, I still have plenty to learn!
thelocust is offline Find More Posts by thelocust
Reply With Quote
Old Nov 09, 2005, 08:46 AM
Permanently Banned
Dallas TX
Joined Oct 2004
1,551 Posts
Airspeed - airspeed

Quote:
Originally Posted by thelocust
1. Ensure all physical trims on the ground are in good order. Elevator flat (full-flying ones are tricky), rudder straight, ailerons and flaps good.

2. Fly it fast - this will give you a good indication of any trim issues. This also includes doing a dive-test which will get you up to that high speed. If the plane pulls up when speeding up, you are nose-heavy.

3. Fly it slow -- see what thermal camber and landing flaps do to it while you have altitude.

4. For a poly plane, see how long it takes for you to initiate a turn with the rudder. This can give a good indication of not only rudder throw but proper washout/in on your tips.

This is assuming that your wing and tail are square and that your linkages are tight.

That's what I've done on handlaunch, 2-meter and unlimited ships. That said, I still have plenty to learn!
Succinct and accurate. Airspeed is the key. If you trim CG for slow flight (to work light lift as prime interest), your machine will be nose heavy at lower alpha for zipping across the sky - with the converse true but showing up as tail heavy when trying to float at high alpha. [With CG back for performance, I tended to land hot; whereas, with my light air machines I could 'creep' onto the spot.]
histarter is offline Find More Posts by histarter
Reply With Quote
Old Nov 09, 2005, 03:15 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
10,886 Posts
Histarter, I think you have the right idea but perhaps expressed it wrong. CG setting is not really speed dependent and should not be set that way. What the CG position gives you is more or less pitch stability. Some pitch stability is a good thing but too much results in strong trim changes as the speed varies as you've mentioned. But too much makes it more work to fly the plane. And as noted the more to the rear the higher the performance but that performance should not affect the flying speed or ability to trim the glide unless there are design issues.
BMatthews is offline Find More Posts by BMatthews
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Question How do you trim your motor offset? irish_lord99 Electric Plane Talk 6 Aug 22, 2007 12:35 AM
Discussion How Do You Retrieve Your Plane? CheckMail Slope 56 May 10, 2006 10:02 PM
how do you put your plane in your car securely? guoxiaotian Fuel Plane Talk 3 Oct 20, 2004 04:26 PM
how do you store your plane(s)? torcgolf Slope 12 Apr 02, 2003 08:07 PM
How do you weigh your plane? mcart1956 Electric Plane Talk 11 Jan 26, 2003 09:18 AM