How to Flight Trim an RC Airplane
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- čas přidán 1. 07. 2024
- How to Flight Trim an RC Model Airplane
In this video I will show you how to flight trim a radio control (RC) model airplane. Trimming any airplane in flight, full scale, RC model or free flight, is a basic skill of any pilot. An airplane that is aerodynamically trimmed can maintain a constant altitude or airspeed without any control forces being present. All airplanes need to be trimmed for normal flight.
An aircraft has three axes of flight: Pitch axis, controlled by elevator. Roll axis controlled by ailerons. Yaw axis controlled by rudder. The roll and yaw axes for light aircraft ofter can be set on the ground. The pitch axis must be trimmed during each flight to account for airspeed, center of gravity location and configuration changes.
Our RC models have a built in electronic trim function that is easy to set during flight. As trim is set for an airspeed, the pilot must choose an airspeed to trim for. In this video, I select straight and level flight at 2/3 throttle setting. Once the radio control model is trimmed at this airspeed, the pilot should be able to take their hands off of the controls with minimal movement of the airplane.
I also discuss the use of sub-trims on the RC transmitter, and the ability of the RC transmitter to retain all trim settings in the computer memory.
Here is a link to my CZcams Channel:
/ timmckay56
Many thanks in advance for a post of this video on Facebook, it truly helps the channel a lot!
Regards,
Tim
F-22 video and plans:
• F-22 Foam Board RC Air...
Chapters
00:00 - Intro
00:12 - How to trim and RC model airplane
00:58 - Three axes of flight
02:28 - Why we trim
03:45 - Why we trim
04:35 - Full scale trimming
08:48 - Center of gravity
10:15 - RC trim basics
13:04 - Trimming your RC model
17:40 - Sub-trims
19:53 - Transmitter memory and trims
21:05 - Difficult trim
Thanks once again, Tim! I hear this term a million times in RC demo videos, and yet hardly ever do I see it explained EXACTLY what it means to trim the airplane properly! Thanks again for another video helping us noobs to the hobby.
ZZ: Glad it was helpful! Tim
Thank you Mr. Tim
Thanks for checking in! Tim
Thank you! I'm just starting in the hobby, You explained it well.
😊👍🏻 Tim
Hi Tim, one of ur older vids has inspired me to do a rc conversion on a guillows bird dog this winter. although im in my early 40's and been into model aviation over 30 years ur rubber to rc conversion vid took me back to being a kid dreaming of micro rc that wasnt really a possibility in the late 80's
👍
4th: Welcome to the channel, and best of luck with your conversion! If I recall, the Bird Dog has a 19" wingspan. This is a quite small model for an RC conversion, especially when the micro gear is added. Consider converting the Guillows Aeronca. Per my video on this, one of the best flying Guillow kits, I like it a lot. Tim
Thank you Tim! Finally a nice video for us newbie rc pilots. I am only in the 2nd year in this wonderful hobby and did not fully understand trim. Plus you answered another question that I have always had. When you trim a plane during flight, I thought you were trimming for just that flight. I now understand that the trim will be saved in the 250 model memory for each plane. I could never find out about this in any of my manuals of the planes or my transmitter.
Dave: Thanks for checking in and your kind words. RC airplanes are a lot of fun, been doing this for over 50 years. Welcome to the hobby! Tim
Thank you Tim for the excellent tutorial. Just getting back in to the hobby after many years away and your videos are an excellent reminder and retraining tool.
Please keep them up.
Cheers from Canada
Robert: No worries and thanks for your kind words! Tim
You finally said it, "trim for airspeed". I know a lot of pilots (full scale) who cannot understand this.
JL: Thanks for checking in! Tim
Great video Tim, I think I'm going to watch again.
David: Thanks once again for checking in! Tim
Good stuff thank you. Just starting with RC Aircraft.
MZ: Best of luck! Tim
Very good information for beginners in the video. One recommendation however is to always remove the propeller on a model when working on the bench, especially when playing with the radio settings. Very easy to accidently start the motor and make a mess without talking about injuries.
MX: Fully agree, thanks for this reminder. Tim
15:40 Instead of relying on a buddy for helping with setting trums, I set the trim sliding switches for cross-trim.
That is, I set up the trim sliding swiches that are on the left-hand side of the transmitter to control the trims for the stick on the right-hand side, and conversely the trim sliding switches on the right-hand side to control the trims for the left stick. Thus, the elevator trim is set by the sliding switch that would normally control throttle trim.
Why? That way, I can set the elevator trim with my left hand while simultaneously controlling the elevator stick with my right hand.
If you dig into the transmitter menus, you can find where to setthe trim switches to specific channels.
Great inputs, thanks! Tim
good vid my friend I appreciate that information!! thank you.
👍🏻 Tim
Interesting about "trim for airspeed", never thought of it that way.
David: Yes, that is the way it should be taught. Tim
I’ll never forget early in the hobby I noticed the downward and to the right pitch of the nose and prop and thought I better fix that! 😂
All good! Tim
Sir... thanks for your information video 👍
BD: Any time! Tim
Very good advice. Could have been supplemented with a few video's where you have diagnosed it as mini clips. Noticed on your posts you have footage to back it up very well.
Mark: Good tip on adding videos, will do next time! Tim
Thanks :)
👍🏻 Tim
The F22 should be very pitch stable, the cg looks a little far back to me. I'd first creep it forward a bit. Then give it a little more expo and a little less throw. I like the idea of going back to set the trim with the sub trim, I never looked at it that way. I usually use the sub trim to square off the geometry of the servo and control surface on initial setup then use the main trims to trim in the air then leave it.
Greg: Good idea in inching the CG forward a bit, will give that a try! Tim
Hi Tim great job on this video thank you. I also do not put wheels on my foam planes. I was wonder the main reason you don’t?
No wheels allows for a faster build and a bit less weight, that’s all. 😊 Tim
Thanks Tim just curious
First like Tim❤️👍.
Thanks! Tim
@@TimMcKay56 I made a weight scale for measuring my airplane weight, it will do gram,ounce, pound, with just a slide of a button. Now it's development finished.
@@Ciiads Perfect! Tim
@@TimMcKay56 next I want to make a radio control. this video is a wonderful info I would like to add the trim control to my new radio control design. Thank you Tim.❤️👍😊.
@@Ciiads Good luck! Tim
Hi Tim. Any idea on how to When using Spektrum transmitters, set the lower endpoint of the throttle channel (CH1) to -120% to start the motor on a Dx5e transmitter?
Not sure . . . do try www.RCGroups.com Tim
Hey Tim great video! What's the story behind the "Quickoats" name LOL?
AB: The Quickoats is a "copy" of sorts of the old time free flight gas powered models of the 1930s. One of the more famous of these large free flight models was the Quaker, thus this smaller version called the Quickoats as it is a quick build. Tim
@@TimMcKay56 Ah OK very cool, thanks for the explanation. I was just curious as my wife calls me Quickoats as I eat a lot of oatmeal, in the Quickoats variety LOL.
Thank you for your video ,very nicely explained. My first plane i built crashed on take off. I do not know if i could start take off and if it banking on one side land it quickly before it gains height and adjust it. I am also not sure if the plane was too heavy for the motor size and caused it to stall . Is there a chart weight of plane and motor required. Thank you
Saleem: No such chart exists, as each airplane different. Sounds a lot like you were slow on airspeed, classic stall/spin accident. On any test flight accelerate straight ahead before trying a turn. Good luck! Tim
@@TimMcKay56 Thankyou for your quickj response and advice , your videos are excellent.
@@saleemkader2126 Thanks! Tim
Since you mentioned warp, could you demonstrate fixing a wing warp. I have a glider with a 72 inch wingspan. When I hand toss the plane will go out about 20-30 feet and drop the right wing tip and crash on the nose. I had someone tell me I have a wing warp. So, I need to know how to fix it. Larry
Larry: I can add that video. Pretty easy to check for wing warps. Either look carefully at the wing, see if there is anything not flat on the underside of the wing. If the wing allows, see if it lies flat on a building board or flat surface. I only know how to fix a warp with iron-on covering . . . twist out the warp and use a heat gun to shrink the slack covering, usually works quite well. Tim
@@TimMcKay56 my wing is covered with monokote. I do have a fairly large work bench to test it out. The wing is a polyhedral so I expect I need to test all 4 surfaces.
@@larrypaine1523 Larry: Perfect, MonoKote makes any warp adjustment super easy. Just twist the opposite way, shrink the wrinkles, and you can get to a no-warp wing. Tim
Do these controllers save your specific trim settings for each aircraft that you attach to it ?
They do. Trims are set and matched in that model’s memory. Tim
Hi Tim
Very detailed video but did not help me.
Another oldie getting into rc flying. Solo in the field behind my house.
Getting the hang of RTF park flyers but lost two after lost visual. Got a larger Ranger 1600 for Christmas but the pitch is so sensitive that I have had to abort all flights.
C of G checked and elevator travel minimal.
Where am I going wrong?
Any advice would be appreciated.
Tom: My recommendation would be to see if you could visit a local RC club (just do a Google search) and see what the guys there are flying and what they like as trainers. It could really save you some time and heartache, perhaps avoid a crash. Also, if there is a local hobby shop nearby they may have some recommendations. But a RC club is the best bet. Tim
@@TimMcKay56 thanks for the prompt response.
I know that I should join a Club and contacted one last night. Model shops are getting very thin on the ground here in Scotland.
After I sent my query I found your video on CG and looked at the manual again. It seems correct but as the plane is marketed as FPV it can take a heavy nose weight.
In the meantime I will repair the plane and try it with more nose weight.
@@Pufferman Sounds good, best of luck! Tim
I do a couple things differently that traditionalists don't like. First, I make a throttle curve for trimming that has a flat section at the power / speed to use. I only use it for trimming, but it allows speed to be repeatable if I make mechanical adjustments to zero trim and fly again. I only need to have the throttle position close to get the same setting every time.
Second, I do trim for landing speed. I do this by mixing R Knob to Elevator. It is set for a small range but allows me to quickly dial in trim for landing speed and dial it back out for cruise trim. Have to really watch the nose coming up too quickly and trying to stall when dialing it in while still a little fast. But a quick bump of down elevator usually corrects it as speed bleeds down. Again, this allows for repeatability of speed and trim when landing. I watch too many flyers that are far better than me while flying, damage their aircraft while landing because they were too fast or too slow.
Mark: Great points, thanks! Tim
One problem I've run into with trimming is that flaps aren't always even. A plane may develop a roll when the flaps are deployed. The way to deal with that in a Spektrum radio is to tie your flight modes to your flap switch. Then you can have separate trims for each flap setting.
CG: That is an excellent point regarding asymmetrical flaps, thanks! Tim
You need a separate servo in each flap so you can adjust them to be even.