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Kerak
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Re: Problems with thrust on a Sopwith Camel
Reply #3 - Sep 21st, 2021 at 9:03am
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Interesting problem with the Camel.  I've constructed quite a number of them over the years and never had a great deal of success with their trimming...mostly (I believe) a result of that extremely short nose moment.  That brings us round to the cg again.

My number one head-scratcher has always been the theory behind the dihedral setup...i.e., zero on the top plane and considerable on the lower.  It's like an effort by Sopwith to get some stability into the design...and still preserve maneuverability.  The history of the Camel that it was extremely "squirrely" in flight...and torque of it's Clerget or Bently engine could be a real killer...the total combination of effects.  Whenever I could corner a legitimate credentialed aeronautical engineer I used to pick their brain about the Camel's dihedral (theory) and never did get an answer that I understood...baffle them with bs.....

Oh, no...I too have no answers for you...except that Camels have been very successfully flown in the rc venue...ability to "control" things.  Also...peanut scale exacerbates all of these negative tenancies...scale effect.  While musing over various designs for my next project, I came across this modeler's interesting solution to a trimming difficulty:

"It was a great flyer once I hinged the rudder so it could flop around. This wouldn't be good indoors as the circle is a bit erratic. Before I hinged the rudder, it would dive to one side or the other. I think when everything was tuned up I would get about a minute in still air."

Seems he created a form of "auto-pilot" to correct attitude issues...a form of elevator/aileron control...two-channel, back in our rc days (albeit those controls are fixed in place).  Careful with "auto-pilots."  The model had to be able to fly out of your hand because any thrusting motion can induce unintended and adverse control input.

Best of luck, John.  Smiley

Neal
  
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Sky9pilot
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Re: Problems with thrust on a Sopwith Camel
Reply #2 - Sep 20th, 2021 at 10:17am
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I'm with Ian as well...check the CG.  Great suggestion on setting up the glide and then add the prop.  Keep us informed of the progress please.
  

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pb_guy
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Re: Problems with thrust on a Sopwith Camel
Reply #1 - Sep 20th, 2021 at 10:14am
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Welcome John. I don't know what the problem is. I did think about it, and all that came to mind was C/G. The C/G might be too far back and the plane could benefit from some nose weight. If you take off the prop, you can balance it for a 'glide' with clay and then put the prop back on and balance it at the same point and try again.
ian
  
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john brama
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Problems with thrust on a Sopwith Camel
Sep 19th, 2021 at 2:28pm
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Resently did a scratch build peanut size Sopwith Camel. I am  having no end of problems getting anything close to a flight out of it. I started with a Peck Pylmor 4.75 prop with little or no results, the airplane just hangs in the air with no forward motion. Tried a Peck Pylmor 6inch prop, it produced one short flight and know is doing the same as the 4.75 prop. Tried all sorts of different sizes of rubber and horizontal stab and rudder location with no improvements.The plane is a bit heavy which probably isn't helping.  Any idea's as to what to do would be helpful,Thanks
  
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