How many squares would you say...
 

...it would take for a twin TD .010 Skyrocket?

I finished the rough draft of the plans for my contest entry (done with a stubby pencil) and I like the way it looks. But the wing looked a little smallish. I'm not worried about it being too fast but I would like to be able to do some mild aerobatics. So a lower wing loading might be a good thing.

I will use a 50 Mah battery, two 9g. servos (aileron and elevator), and a GWS rcvr. The single Perfect tank looks to hold about an ounce (with a T fitting between the engines so they will die at roughly the same time). The tank can be easily enlarged and I am used to short runs with my .010s so I will start off with the small one.

The wing is about 130 sq. in. right now. I could extend it for 150 - or make it smaller. What would you guys recommend?

BTW, I tried to send this message via the '1/2a all the way' site but I'm not sure I did it right.

RE: How many squares would you say...
 

Perhaps a little more information would help.

The Grumman XF5 Skyrocket was an experimental design of the WWII era. It was intended for carrier operations and boasted two radial engines in a more or less conventional airframe.

Last Summer I scratched together a 'proof of concept' model I ended up calling the 'Hoot' because it was a hot little hummer that was a hoot to fly. It had a single TD .020 for power and carried about 90 square inches of wing. Since Hoot is quite fast I decided that my Skyrocket should have a little larger wing to carry the extra weight and for (hopefully) added stability if/when the engines quit not at the same time.

RE: How many squares would you say...
 

Cool project!:) Here's my 2 centavos worth. I like to build as big & light as I can and still accomplish the mission. Me? I'd try for 200 sq. in and 12 oz. or so. My little KwikStik 010 has 121 sq. in. and weighs a tad under 5 oz with a single 010.....it flies with authority! Your Skyrocket wing would have to be scaled up in relation to the fuse & nacelles to keep the overall size & weight within reason. My brain power doesn't go much farther than a rough idea; then I start drawing in CAD, scaling the parts up & down 'til it looks close enough. Then I try to engineer all the excess weight out of the structure I can and see what comes out!

RE: How many squares would you say...
 

DB,

Thanks for the reply and recommendations.

I was hoping for a ten-ounce OA weight. So a 200 sq. in. wing would produce a nice wing loading (i'll do the exact math later).

I intend to cover it with laminating film with floral spray on the 'glue' side for a reduced weight, semi-transparent look. So I expect my target weight isn't too optimistic.

I have been unable to take enough time with TurboCad to be able to draw even the most rudimentary top view. So I stick to the stubby pencil on 1/4-square paper. If I want to change scale Mr. Kinko has proven to be quite accommodating.

Thanks again for the input. I DO appreciate it!

RE: How many squares would you say...
 

Ray,

Unless you are building it with profile nacelles, those 3 1/2 props will need
to function as ducted fans to get any thrust!
There WAS a "paper" version of the XF5F with more streamlined nacelles
and a spinner, but it would be a "scale" model of a plane that was never built.
(I drew up a 42" span XF5F for two Cox .09's when I was a teen, never built
it though.....ah, another someday project... Inspired by an old '40's issue of MAN
I had back then with a Skyrocket on the cover and a nice 3-view inside.)

Get the CG in the right place, it should fly! You will win the smallet XF5F award
for sure it it does.

If I can find my 3-view that shows the streamlined SKYROCKET, I can post it if you are
curious.

Dave

RE: How many squares would you say...
 

Dave,

I don't intend to use ANY nacelles. Just the lovely little TD screamers stuck to 1/8-in ply firewalls at the LE of the wing. I am building a sport model as opposed to even a SEMI scale job. Since I want to put Blackhawk insignia on the wings I couldn't 'sell' it as scale anyway.

I have several reference items including a version by Nick Ziroli a CL design by Jack Sheeks.

I haven't mentioned it yet but I am going to build it using a flat-plate airfoil (1/4 inch thick) where the wing and fuselage bottom is built flat on the board in one piece. Then I'll add the firewalls, the rest of the fuselage, and the twin rudder-tail section "in the air".

I was thinking of putting a slight camber in the horizontal tail surface so I could use light wood without warp problems. But that may be subject to change.