fly boy3 Posted August 18, 2009 Share Posted August 18, 2009 Hi all,I am refurbishing a 45inch span biplane with a small backward sweep to its wings. Is there a rule of thumb regarding the position of the centre line of the wheels (no plan) ,possibly in relation to the c of g or from the wing leading edge.I am trying to prevent ground loops or a nose over. A rule of thumb similar to (1/3 chord for c of g.) is what I need. thanking you, flyboy3 Quote Link to comment Share on other sites More sharing options...
Pat (rActive) Harbord Posted August 18, 2009 Share Posted August 18, 2009 I found this article for youhope it helps Quote Link to comment Share on other sites More sharing options...
Doug Ireland Posted August 19, 2009 Share Posted August 19, 2009 Umm, that picture is of a monoplane, not too relevant I would have thought! Sorry fly boy3, can't help you on this one but someone out there will have an answer. Quote Link to comment Share on other sites More sharing options...
Jimbo565 Posted August 19, 2009 Share Posted August 19, 2009 FB3,This is my Sierra Sportster similar to the bipe you are describing,it behaves very nicely on the deck ,as long as the wheels are just in front of the leading edge you should have no problems, Jimbo. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted August 19, 2009 Share Posted August 19, 2009 I think I might be able to help . On a mono plane it is normal to get the wheels about 30 degrees minimum forward of what we refer to as the C of G all the time, as measured by balancing the model using the wing (horizontal positioning only of the C of G as we call it ).However with a bi-plane one has to take into account the position VERTICALLY because the centre of lift is also somewhere between the wings.!! .Having found it ( many obvious methods you could use )-draw your theoretical "line" from it & then apply the 30 'ish degree rule again Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted August 22, 2009 Author Share Posted August 22, 2009 Thanks to all who replied to my u/c position problem.Temp.positioned u/c in front of leading edge using"if it looks right" theory,and it was only about 1.5cms from position worked out as per calculations. flyboy3 Quote Link to comment Share on other sites More sharing options...
Pat (rActive) Harbord Posted September 9, 2009 Share Posted September 9, 2009 Posted by Doug Ireland on 19/08/2009 00:02:29: Umm, that picture is of a monoplane, not too relevant I would have thought! Sorry fly boy3, can't help you on this one but someone out there will have an answer. So Doug I wasn't too far out after all and it is a pretty diagram FlyBoy - did it work OK? I would have thought you are in the right ball park Edited By rActive on 09/09/2009 08:07:54 Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted September 20, 2009 Author Share Posted September 20, 2009 Hi all,thanks to all who helped with my u/c problem which is now sorted. Could any one tell me where I can obtain an aluminium u/c as fitted to an Acro Wot, and also to my venerable old trainer, the Yamamoto. Thanks fly boy 3 Quote Link to comment Share on other sites More sharing options...
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