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Hot Topic (More than 10 Replies) Questions about trimming (Read 6357 times)
Widdog
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Re: Questions about trimming
Reply #17 - Apr 5th, 2016 at 7:49am
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Thanks much for the great advice. I'm celebrating my first 00S out of sight flight. I set up an old Jimmie Allen peanut tri plane to electric free flight. The last flight i had with it i set the time for 20 seconds. https://youtu.be/UcWb0JEL_Cg
  
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Widdog
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Re: Questions about trimming
Reply #16 - Jan 9th, 2016 at 10:18am
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Thanks for the info Sky9pilot. That sure is a great video.

I'm starting to wonder if my flying field might be a bit too small. There is enough room to fly a small RC. My field is surrounded by tall tree's.

The weather was perfect for flying Air Hogs today. I thought some video of my flying field might help explain.

https://youtu.be/OOGp_WDqEe0
  
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Sky9pilot
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Re: Questions about trimming
Reply #15 - Jan 8th, 2016 at 7:51pm
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Tom Hallmann has a video entitled Seafire - Anantomy of a Trim Session Click Here

Explains the gurney flaps (strips of 1/16"sq strips) applied to trailing edges of wing. Approximately 2" long and timmed shorter or added to in order to get desired results.
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Widdog
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Re: Questions about trimming
Reply #14 - Jan 8th, 2016 at 5:01pm
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Thanks Sky9pilot sounds like a good idea to me. I don't know a lot about gurney flaps. I will work with the wing tip clay idea. My last couple of builds don't seem to want to fly circular patters. I could not get this Guillow's Cessna 150  reduced to a 17 inch wing span model to turn either. I think i got pretty good flight time but no turn. Also it seemed to go straight for the tree.https://youtu.be/7qXRZqKBThk
  
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Sky9pilot
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Re: Questions about trimming
Reply #13 - Jan 8th, 2016 at 12:35am
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Widdog...you might try gurney flaps on the trailing edge of the wingtip/tips or a dab of weight on the inside wingtip of the way you want it to turn. Or combination of both. Just a thought.
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Widdog
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Re: Questions about trimming
Reply #12 - Jan 7th, 2016 at 5:32pm
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I think I'm getting better. I have been having a lot a bad luck with trees lately. Anyway I think i had a good flight time this time. However, I'm getting a bit frustrated with the model flying straight all the time. If I try to add any left rudder it wing tip stalls hard into the ground. I will try to adjust my thrust angle like was mentioned to me earlier.
https://youtu.be/d2e7AREtmIQ
  
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Widdog
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Re: Questions about trimming
Reply #11 - Jan 6th, 2016 at 9:13pm
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Thanks for the info Staubkorb. I  am reminded that in outside flying endurance is definitely a goal. You are totally correct I should focus on stretch winding. A kind of funny thing about my models is they always seem to want to fly straight for the  closest tree. If I trim in to much turn the model wing tip stalls and crashes. Not enough turn and into the  tree. I guess that's the challenge. My flying field is a soccer field surrounded by tall trees. Just barely not large enough it seems.
  
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staubkorb
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Re: Questions about trimming
Reply #10 - Jan 6th, 2016 at 11:12am
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Doubt it, but...
Depends upon a number of variables, but breaking down and getting a winder - even the cheapest variety (Sig/Peck 5:1 good for up to four strands of 3/16ths) will allow about twice the number you're "hand winding" if you stretch the rubber out before you start winding, on the existing motor .  There are a huge amount of references to winding techniques here on S&T and all other FF Forums that I'm sure you've already seen.

400 HAND winds is putting that motor near (or beyond) maximum torque, which is probably THE reason you've had so many trimming issues and why the model takes off like a rocket.  It does seem to fly nicely - adding a bit of right thrust should get it into a right turn under power - just a little bit at a time, and only ONE adjustment at a time.  Stretch winding allows a lot more turns (on a 1/8th loop, about 100 turns per inch - safe 85-90tpi), so if the motor is 10 inches long you can wind approximately 900 turns safely.
  

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Widdog
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Re: Questions about trimming
Reply #9 - Jan 6th, 2016 at 9:24am
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Jimmy Allen peanut semi scale scratch built. I think this plane has a lot of drag. I used 2 strands of 1/8 inch rubber. The rear motor mount is a wire hook at the back of the model. I am able to hand wind in 500 winds. I think I'm about I'm at the max for this model as far as flight times goes. Now the other day i flew a Guillow's Skyraider at 400 hand winds. The Skyraider had a fairly long flight with the 400 winds. Now my question for now is... Can i get more flight time out of this model via hand winding? https://youtu.be/wKPva6agHSc
  
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Widdog
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Re: Questions about trimming
Reply #8 - Jan 5th, 2016 at 12:53pm
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I got I chance to apply the great advice I got here on my flying. I wanted to give credit where credit is due. Wow powerful medicine here. I was trim flying with 4 hundred hand winds. I could not believe how high and far the model flew now that I know the fundamentals of trimming. Thanks much advanced members.
  
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terryman
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Re: Questions about trimming
Reply #7 - Jan 4th, 2016 at 12:43pm
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Sky9pilot wrote on Jan 3rd, 2016 at 6:42pm:
Lots of guys use strips of 1/64, 1/32, 1/16" ply just for that reason.  You don't get the crush of balsa and a drop of duco anchors it so it doesn't fall out.  There is also Terry's solution with flathead screws in the ply nose facing former.  I think he uses thinned Cya to harden the threads after they are first cut with the screws.  Remove the  screws first then when dry re-insert the screws.

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So far I have not needed to harden threads in plywood with Cya but it seems like a good idea.

Terry
  
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Sky9pilot
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Re: Questions about trimming
Reply #6 - Jan 3rd, 2016 at 6:42pm
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Lots of guys use strips of 1/64, 1/32, 1/16" ply just for that reason.  You don't get the crush of balsa and a drop of duco anchors it so it doesn't fall out.  There is also Terry's solution with flathead screws in the ply nose facing former.  I think he uses thinned Cya to harden the threads after they are first cut with the screws.  Remove the  screws first then when dry re-insert the screws.

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Widdog
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Re: Questions about trimming
Reply #5 - Jan 3rd, 2016 at 3:42pm
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Well today I noticed something kind of strange with my nose block. Well not so much the nose block but the thrust adjustment shim. I used Balsa wood and long story short it got squeezed to half it's width. I replaced it with a shim made from a 1/16 inch thick popsicle stick shims. Hopefully will be able to get better flights with the new shims.
  
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Widdog
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Re: Questions about trimming
Reply #4 - Dec 27th, 2015 at 9:10pm
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Thanks for the info and posting. I also thought was a cool crash into the tree. It actually was a wing that came off. I was able to glue it on good as new. Weather has been bad for flying. I will try it again soon weather permitting.

Well as far as modifications. I did build it from 1/16 inch Contest Balsa. I also made it with a removable nose block. The nose block seems adequate and I don't think loose nose block is a issue. If I had a flying club I could probably get a better opinion on the matter.

Speaking of flying clubs I m probably the most knowledgeable model person around here. I of course want to start a club but need a bit more training.

Very interesting your thoughts on the 1/16 Sq rubber. I used 6 strands of 1/16 ". The plans recommend 1/32x3\32 . Now a days I think rubber is 1/16 inch thick by 1/16 or 1/8 or 3/16. I really don't know but I do know that the knot works out better with the thread rubber.

  
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terryman
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Re: Questions about trimming
Reply #3 - Dec 27th, 2015 at 10:49am
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Widdog,

Those were great looking flights until the tree intervened.  Sorry to see that and hope you can patch it up.  At the same time the kid in me was thinking what a cool crash!, with  the elevator or whatever fluttering down. 

Did you make any trim changes other than the 1/16" motor strands?  How many strands did you use?  I've read multiple small strands are roughly equivalent or able to take slightly more turns than an equal total width with fewer strands.  For example 4 strands of 1/16" vs 2 strands of 1/8" respectively.  I have done such occasionally but not paid enough attention to notice a difference. 

Was the kit built per plan or with modifications?

Terry
  
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