Hi Jim,

Cool idea.  I'm going to be monitoring the input and will try to keep from throwing too much in right away.  I think that will generate a lot more input than the other way.  Right or wrong (and believe me, I'm not any rocket scientist on this stuff) when somebody with a bit of a record of success expresses a point of view on this subject it tends to get accepted as gospel and discussion breaks down.  Ergo, I'll keep a bit quiet until there's been some discussion already. 

What I will promise to do is to step in with an opinion if I see something gaining momentum which is out of step with my understanding of how these things work.

My only comment at this point would be to start with a realistice assessment of what weight you're likely to be able to build this critter.  Everything else has to pretty much evolve from that prediction.  Be really critical and honest about past performance (your own at the building bench) and work from that premise.

The other thing you need to do once that is determined is figure out how much area you've got in the existing unflapped wing so you can make a determination of what you'll need to do in terms of flap area and movement to handle the weight.

One final clue, you've probably read enough of my ramblings to realize that, while I think stunt ships should be as light as you can reasonably make them, I'm not one that thinks missing a target weight is an automatic disqualifier for a good airplane (Lord knows, I've played that game over the last fifty years!)

Ted

>>Be really critical and honest about past performance (your own at the building bench) and work from that premise.<<

Wish I had some sort of consistent benchmark to draw from. I seem to build an insanely light plane followed by an unacceptably heavy plane, followed by a very light one...ad nausium.

The Cobra I'm building looks to come in under 40oz. The new PA plane (at 740 squre inches) also looks to be quite light, coming in at under 55oz. But the plane I built last winter was a real pig. And the one before that was no lightweight. I don't see that my building practice is much different from plane to plane.

Hmmm...Maybe it's those helium tanks I just had refilled...

Well, your moderator just spent a couple of days in heated discussion with medical professionals.  The occasion for which was to study the affects on the human body of crashing one's bicycle at about 10 or 12 knots.  I believe the Brits would term the ultimate maneuver a "bunt".

Suffice to say, the bicycle fared better than did the bicycle rider.  Seriously dislocated left shoulder (posteriorly which is,  I'm lead to believe, much rarer that the garden variety anterior dislocation suffered by mere mortals).  In addition, the knobby end of the bone (the humerus) suffered a break although they expect that to heal on its own assuming the life support system for it remains intact and functional.

Other than that, a very stiff neck (ya ought'a see the funny looking bicycle helmet now!  It doesn't look so funny after performing its magic, I'll tell you).  A very funny red ring all the way around my nose, a fat lip which makes me lisp even more than usual and a knee that looks like a fat toddlers after falling out of the tree house.

Four to six weeks for recovery assuming something more insidious doesn't sneak into the picture during physical therapy and then I'll be as good as new.  The doctor said there should be no reason I won't be able to win the US Open once I'm cured.  Which is good news inasmuch as I have a hard time winning the Fancher Open on even my best golf days prior to the spill.

Probably make completing the Jamison for VSC OTC out of the question.  I should be able to finish up the detail items on the Ruffy with no problem once I get out of the sling though.  Probably show up at VSC once again hoping to get in a maiden flight before officials start.

So, Jim, if you leave off the wingtips what's the span going to be?  How about the aspect ratio?  (I'd assume the flaps will be somewhere between 22 to 25% of the chord at all stations and probably full span).  Anyone want to discuss why that is of interest?

Ted

Randy,

You COULD pull a Tony Lang and paint your ship at the
contest! No kidding, he actually built a model at the site,
painted and finished it. The Arizona sand kept him from
a 20-point finish.. ;->

Ted, I'm wishing you well on the injuries. Take care of yourself,
things don't heal like they did when we were 25 years old.

Best,

L.

Ted, all

Wing Span is 59" with the tips
Root Chord is 10"
Tip Chord is 8 and 3/16"
Aspect Ratio is appx 6.4 without the flaps

Yes Ted, please enlighten the rest of us about the 20-25% full span flaps?

I'm guessing that about 23% will give a total wing area in the 663 sq in range.

Jim Pollock   

Ted, All

Well, it's time to decide on moments and stab/elevator area and ratio.

From general convention, I would expect 9.5 inches of nose from the leading edge of the wing to be about right and maybe 17.25 inches from the trailing edge of the wing to the trailing edge of the stab.  I know that's not the aeronautical engineering way of figuring things but, modelers use it pretty often.  So, I will too!
I expect the wing to be 663 Sq. In. with the flaps, so we need to develop a stab/elevator combination that will easily change the direction of this thing.  Oh, yeah, just one more thing, this thing's name is going to be Excelsior, that's a sister ship to the Enterprise - sorry Randy!  I just like the always higher aspect to the meaning of the name. 

I guess I'll need to go back over to the SSW forum and look up Brett's formula for determining an appropriate area for the stab/elevator, I think a final product over .56 is desired?

Jim Pollock   

Designers,

     Thanks to Brett I now am armed with the tail area ration formula it is.

             Tail Area X Tail Moment / Wing area X Wing Chord  (at root I suppose?)

             Where Tail Moment = CG to the 1/4 Chord of the tail group
             (ie, Stab and Elevator) actually CG should also be the wing 1/4 Chord
              I believe, but Brett uses CG for simplicity.

             Lets see:   My Stab/Elevator combo as I have laid it out on paper has
            a root total chord of 6.75 inches and a tip chord of 5.0 inches.  The span
            totals 26 inches.  so the tail group area = 6.75 + 5.0 / 2 X 26
             which is; 152.75 sq in.  My wing area will be 663 sq inches and the
            chord flaps included is 12.75 inches the moment arm from the quarter
            chord of the wing will be 25 inches.  Lets plug these figures into the
            formula and see if we can get something over .4 for an answer.

                                      152.75 X 25  /  663 X 12.75  =  .4517493

             Yes that gives some over the .4 goal!  I suppose we can add a little
              more area or moment arm if we can balance it with the engine and
              other items in the nose! 

              Thanks for all the suggestions so far.  Now we need to come up with
               what the fuselage and vertical stabilizer will look like.  I already
              know that DD suggested determining the side area of the Infinity
             then squaring it?   Naw, I don't think so.  Maybe just a little less than
             the Infinity.  Too much side area can be as bad as, or worse than
             too little I would think!  Ted, what do you think regarding side area?

             Jim Pollock javascript:replaceText(' ', document.postmodify.message);
Tongue

Hi Jim,
The "design" sounds good!  The Excelsior  should have all the right numbers.  My first post on this was my thinking that about 62 oz. might be a good weight.  And I wouldn't be afraid of it in the mid 60s. How does it look so far, weight wise?
I missed the power train you are planning to use. ??

Bill,

The power train is a PA .61 with the hi-tourque pipe.

Jim

I don't know how I missed that, Jim!  I just went back to your original message and saw it! 
Thanks!

Bill, Robert

Why is every post I make numbered post #19??

Just curious.  Do I need to change something somewhere?
also, it seems now when I try to pull one of the smily faces
into my text the entire text of the script is displayed...... minor
I know, but still a bit annoying.  Well gosh, I couldn't even get
one to pull into this post as evidence...aaaggghhhh - oh well..

Jim Pollock

Hi Jim,
The smiley is there as I red your reply, but I don't follow the "post #19" part. (??)
Bill <><

I'll vote for a 2" Randy Aero Needle Nose Spinner, Randy Aero Carbon LG and a painted canopy. Oh, and red, white and blue, with lots of stars, please.   Steve

Bill, Robert

Why is every post I make numbered post #19??

Just curious.  Do I need to change something somewhere?
also, it seems now when I try to pull one of the smily faces
into my text the entire text of the script is displayed...... minor
I know, but still a bit annoying.  Well gosh, I couldn't even get
one to pull into this post as evidence...aaaggghhhh - oh well..

Jim Pollock

Well I am not sure what you are doing? But I did go in and look at your settings. Let me know if it is working now.

Well for now anyway,

I need to lay of from building this airplane until I get relocated to Anniston, AL
It's time to start packing boxes ect,  Ugh! 

Jim Pollock