[gcarabin]

I have a set of plans from a Terry Tripp (Fixious Designs) for an Extra 300 EX 80" span. I can not find any reference on the plan to a CofG location. ??
Anyone out there familiar with the plans ar the whereabouts of Mr Tripp.
I would like to start on this soon and Have a number of other questions as well . If you are familiar with size Extra I would like to hear from you.
Thanks George C

[moo]

CofG is almost always 30 to 35% of the wing chord from the leading edge.

It really should be on the side view of the plans.

[ronm]

Originally Posted by erg

CofG is almost always 30 to 35% of the wing chord from the leading edge.

It really should be on the side view of the plans.

And it should be real close to the main wing spar, if not right on it.

[Guest]

Originally Posted by erg

CofG is almost always 30 to 35% of the wing chord from the leading edge.

It really should be on the side view of the plans.

Thats a bit of a scary statement....considering the Extra would be a double tapered wing..

30-35% of the mean aerodynamic chord.

I have had models that balanced nearly 50% of the root chord because of the amount of taper...so 30% would be excessively nose heavy.

Do a search on google for mean aerodynamic chord calculators to help you determine how to find the appropriate location at the root to balance. Do not balance it at 30% of the root chord!

Use this exactly as shown.

Ed S

[Guest]

Even better

http://www.scaleaero.com/CG_Calculator.htm

[gcarabin]

Thanks to all who replied. I'm sure I will get it sorted out. What has me concerned is that I bought a "semi finished" kit. Basically plans, fiberglas cowl. Built fin and rudder, and foam wings sheeted. The workmanship is superb on the parts that are done but the wings don't match the plans.
They are about 2 1/2" wider at the root chord and about 1 1/2 ' narrower at the tip. this makes the leading edge about 1'1/4" forward and tr edge about same rearward on the fuse. Everything else matches perfectly. I don't see that it would effect anything ( just be a bit more wing area) but thought I'd ask for more experienced input. .Plans show a Saito 180 but my reading seems to suggest that these 80 in span aircraft will take a DA50 with no problem. I also have a kit for the OHIO RC Ultimate bipe which would do quite nicely with the DA50. And I sure as heck can't afford two DA's.
After buying these two kits on rc canada I have one suggestion. If you are selling something that was not originally yours plse make sure you know what you are selling, that it is all there. not damaged, etc.
Once I buy something it is no consolation that I can return it if it's not as described especiallly when returning it will cost me. I can't afford to spend 50-75 bucks to have a look at something. PLEASE make sure it's what it is supposed to be.If I were a novice I'd really be upset, but I've built a lot of planes in my 30 yrs in the hobby and I'll salvage these two no problem.
Thirty yrs in the hobby and not to proud to ask for advice!! Thanks everyone

GC

[Guest]

GC...

wing planform change as you mentioned wont affect the CG %....just balance at 32% ish

[gcarabin]

I think I have things sorted out!! I did a search of the designers name on the 411 system and lo an behold the only name that came up was himself>

I spoke with him last night and he is going to correspondvia email.
He is flying this plane himself with a DA 50. In fact everything I have he actually built but being a weight watcher he opted for the normal built up wings after doing the foam ones. I think my flying abilities ( mostly fun flying and goin' fast) won't be affected by and extra ounce or two. And it would be a shame to waste the nicest set of foam wings I've ever seen.
.
He claims his plane came in at around 13 lbs with the DA 50.

I love building as much as flying and being slightly over 60, wanted to try something bigger before I croak( hopefully not for a long time)

Thanks one and all and enjoy your summers' flying..

George

[JKovats]

Hey George; you'll love this plane. Terry just joined our club, he's been in the flying Dutchmen in Kitchener for years. Lots of guys fly his designs in this area. He has been continually improving his designs. If he gives you some suggestions, I'd take them. Everybody that builds and flys his stuff loves them. He flys his own stuff all the time.