aroetlin

Hello - I've been working on a Top Flite 1/7th scale P-51 for a few years now, on and off. I've really put a lot of scale effort into it, and am getting closer now to its maiden voyage. Following is a description...

-Engine - YS 110

-Flaps

-Sierra Giant retracts

-Balsa skinned, fiberglassed, covered with Flite-Metal and painted in certain areas.

-Full cockpit, with stand-off scale detailing and pilot

-electronic gear door/retract sequencer.

-JR 8103 transmitter (XP8103)

Dry weight: 12.5 pounds

and the punch line...Wing loading=38-39 oz/s.f.[]

I know I went a little nuts for this scale, but one thing kind of led to another. The extra weight came mainly from gear, scale detail, and finishing. Also, I'm not the lightest builder. I have a habit of reinforcing things.

Anyway, two questions...

1.) Does the addition of a little extra weight in any way alter the CG balancing instruction in the manual? The manual says 3 7/8" back from the LE at the LE break (plus or minus 1/4"). Is that still where it should be balanced? Would you tend toward the 1/4" forward or aft?

2.) Are there any habits during landing about which I should worry (e.g., high stall speed, snap-roll at stall, etc...)?

I would very much appreciate your input before my pride and joy takes to the sky, and obligates me to a landing.

Tony

Bad_Daddy

Oops - delete this, please.

Bax

My Feedback: (11)

Total weight does not affect where the model should balance. The balance point is determined by the areas and moments of the different components. Adding weight will increase the takeoff, landing, and stall speeds, so you will have to be careful in those areas. When you make the first flights, make sure the model has good speed and do a shallow climbout. Too many modelers "horse" the model off of the ground, relying on high engine power to keep it airborne.

During the first flight, work with the model in the slow flight regime. You want to determine its lowest speeds and the attitude of the model. Also work with typical landing approach speeds and see what works out best. Practice landing approaches at altitude, first, so that you can get a feel for the model's handling and still be at a safe altitude for recovery. Once you know how the model will handle at landing approch speeds, you can then proceed to make the first landing.

Please remember that the maiden flight of any aircraft, be it real or a model, is to find the initial handling characteristics. Yes, a full-size airplane will have a lot of things determined by computer simulation, but there can still be surprises, and the number all need to be confirmed by actual flight test.

vertical grimmace

My Feedback: (1)

Another aid when doing a maiden flight is to have your dual rates set up to give just a little more than your low rates. It is sometimes nice to get just a little more control authority if you need it. Also try adding exponential. I never really liked expo for a long time but it is really nice. Maybe start with 45% (+ or -) depending on radio. You want the control to be soft in the center.
Be sure to have your engine running very well and reliably. Point the nose up or pinch the fuel line to make sure you are not too lean. Do not be too rich either. Many tend to run their engines too rich I believe. This will cause it too load up and die. A dead stick is no fun for a maiden flight.
Try to find someone experienced to look it over and pre-flight just to get another set of eyes on it. Yuo may overlook sl\omethng that someone else will catch.

Good luck!

aroetlin

Thanks for the input!

Safebet

My Feedback: (12)

We'd like to see you work of art! Post some pictures. Let us know how the maiden goes. Best of Luck!

SoCalSal

My Feedback: (16)

Just an idea for you..I make up a check list of everything that should be checked before any flight. I use it everytime I fly the plane. It helps the old mind remember things that should be checked before flying. Just like a full scale plane. Pre-flight check list. If you get in the habit of doing this you will have many fewer surprizes during your day at the field. Also include a area for the "Stuff" you should bring to the field before leaving home. It is just a pain when you get to the field and find out you forgot the wing, fuel, screwdrivers, radio, you get the picture.
Take your time on the first flight and you will be O.K.