Seagull 63 inch Harvard/Texan

[yesamen@rogers.com]

Hi guys, I know this is a Motion RC forum and the question I have is not about a Motion product but I'm hoping someone knows something. I bought this plane used but it has never been flown so my setup will be a maiden. I need help with the CG. The Seagull instructions state CG at 60mm back from lead edge AT THE WING TIP. The plane balances close to this with empty tank and my K&B .61 mounted, BUT it looks awefull far back to me. If you consider the average chord of the wing that's more than 1/3 back. This may be OK but my experience tells me it's tail heavy. Any sound advice is appreciated. Thanks Robert

[OV10]

The actual wording is as follows ……………...
"The center of gravity is located 60 mm back from the leading edge of the wing, See picture below."
Per the picture, the 60mm showing from the root chord leading edge puts a parallel line that is relative to the leading edge of the wing tip.
Whether the drawing represents actual 60mm is highly questionable based on the info shown below.
Because this wings leading edge sweeps aft on a approx 1/12 pitch or 5 degrees, it is not of the same standard MAC range of 25-30% that is representative of rectangular wing shapes.
With swept wings the range will increase, so on this model the parallel line from the wing tip leading edge back to the root chord is better than 1/3 back which is to be expected.
I checked three other manufactures AT-6 CG ranges as a sanity check for you.
They all measured from the root chord leading edge aft of the "blivit" as Seagull did and was represented in the pictorial views at around the wing tip leading edge.
Dynam - 1370mm (54) span => CG 70-75mm
Freewing - 1450mm (57) span => CG 70-80mm
Hangar 9 - 1715mm (67) span => CG 105-120mm

Based on yours being a 63 in span, I would use a range of 80-90 and would guess this and not 60 will put it at the wing tip leading edge.
Hope this helps a little and good luck

Best regards,

[yesamen@rogers.com]

Thank you for your reply. I agree with you that the drawing in the Seagull manual may not be proportionally accurate, and my manual clearly states that the CG is 60 mm measured at the wing tip. This puts my CG to 115mm back from LE at the root. That is what had me worried but you have assured me that is to be expected. So accordingly, my Harvard/Texan comes in slightly nose heavy. I will leave it there and when our club field is free of snow I'll do some slow and careful taxi and take off runs. The only other taper wing plane I have is a Dynam Corsair and it's such a POS I don't fly it much.

[Crash-lander]

I have a freewing seagull and I am wondering what size battery was recommended; I’m getting back after moving and losing the manual while moving and being away from flying for 4 years

[OV10]

I have a freewing seagull and I am wondering what size battery was recommended; I’m getting back after moving and losing the manual while moving and being away from flying for 4 years

Crash-lander Hello and welcome to the Squawk. I'm aware of every Freewing and FlightLine produced but am not aware of that particular description.
The Seagull as referenced in this thread is a manufacturer like Freewing is a manufacturer.
Would like to be able to give assistance but you need to be more explicit on what you have.