c-g problem
#1
Thread Starter
Senior Member
Hi folks,
I am just putting the finishing touches to a model, it is a Modeltech VASP, 60" span pattern ship. The c-g is indicated to be 7 inches back from the LE, but I am too nose heavy, must be the heavy MVVS 49 lump up front.
By moving the battery pack half way down the tail and adding 4oz of ballast at the tailwhell I can get it to balance, but this brings the auw to about 7lbs. The destructions don't give any idea of what the auw should be, so a quick wing loading calc gives a figure of 27oz/sqft. This is the first time I have done this calc and I have not included the wing area that is coverd by the fus.
I have no idea what sort of wing loading figures I should be looking at, other than as low as possible.
Ideas or advice,
Cheers,
Chris
I am just putting the finishing touches to a model, it is a Modeltech VASP, 60" span pattern ship. The c-g is indicated to be 7 inches back from the LE, but I am too nose heavy, must be the heavy MVVS 49 lump up front.
By moving the battery pack half way down the tail and adding 4oz of ballast at the tailwhell I can get it to balance, but this brings the auw to about 7lbs. The destructions don't give any idea of what the auw should be, so a quick wing loading calc gives a figure of 27oz/sqft. This is the first time I have done this calc and I have not included the wing area that is coverd by the fus.
I have no idea what sort of wing loading figures I should be looking at, other than as low as possible.
Ideas or advice,
Cheers,
Chris
#2
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Joined: Feb 2002
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From: Kamloops,
BC, CANADA
Wing loadings can be deceptive. The only time you want a low wing loading is on a floater ie: glider or trainer.
I figure at that 27 ounces per SQ. FT. should be alright for a pattern plane. Just don't expect nice stall landings
I figure at that 27 ounces per SQ. FT. should be alright for a pattern plane. Just don't expect nice stall landings
#3
Thread Starter
Senior Member
Originally posted by Cdallas2
Wing loadings can be deceptive. The only time you want a low wing loading is on a floater ie: glider or trainer.
I figure at that 27 ounces per SQ. FT. should be alright for a pattern plane. Just don't expect nice stall landings
Wing loadings can be deceptive. The only time you want a low wing loading is on a floater ie: glider or trainer.
I figure at that 27 ounces per SQ. FT. should be alright for a pattern plane. Just don't expect nice stall landings
Cheers,
Chris
#5
Thread Starter
Senior Member
It went ok, I let one my preferred test pilots do the first run, the take off run was a bit longer than I'd expected, and once I got hold of the controls found it real nice and precise.
The only thing that caught me out was a slight snap to the slow/sharp turns, but apparantly this is to be expected for this type of model - pattern ship and high wing loading - and alas, my landing was a bit slow and it dropped the last foot and damaged the cowl, glad I was flying from the grass strip! Other than that, it handled really nice, and I expect to have a lot of fun with it. It wasn't blisteringly fast, but I expect that it'll get better as the engine gets more run in and I spend a bit more time tuning the pipe.
Since then I have not flown it, mainly been busy with other models, I have taken it to the field many times, but not quite felt ready to fly it solo again without my buddy pilot handy.
Thanks for the interest,
Chris
The only thing that caught me out was a slight snap to the slow/sharp turns, but apparantly this is to be expected for this type of model - pattern ship and high wing loading - and alas, my landing was a bit slow and it dropped the last foot and damaged the cowl, glad I was flying from the grass strip! Other than that, it handled really nice, and I expect to have a lot of fun with it. It wasn't blisteringly fast, but I expect that it'll get better as the engine gets more run in and I spend a bit more time tuning the pipe.
Since then I have not flown it, mainly been busy with other models, I have taken it to the field many times, but not quite felt ready to fly it solo again without my buddy pilot handy.
Thanks for the interest,
Chris



