Ken, thanks for doing the build thread. Most of it is more than I'm capable of but I always learn something new.

Mike

Sent from my SM-A146U using Tapatalk

After careful consideration I decided to bite the howitzer and redo the canard linkage using a reducing lever.  Making it was not easy.
 I had to raise the cockpit floor 1/8" and move the arming plug to the other side.  The lever is two pieces of .5mm carbon fiber sheet with a 3/16" hard balsa center. Ball links are a necessity because of the angles.  IT WORKED!  The canard now has an adjustment range of 5 to 35 degrees and by adding the reducing lever the pushrod angles are such that changing the throw does not change the center as much so I can easily adjust neutral.   On Endgame III I am not able to change the canard much without upsetting the inside/outside turn balance.

The wing is fitted to the fuselage but not glued in yet.  All the subassemblies except for the rudder are finished so it is time to start putting it together and cleaning it up.  The controls are super free.  Hard to believe that with the logarithmic with split flaps, a 5" bellcrank, two pushrods, 10 ball links and a reducing lever that the weight of the flaps is enough to move everything - and the flaps are pretty light!

I put everything on the scales to see where I am weight wise.  58oz including props and battery.  All that is missing is the rudder.  I figure that I will sand and the like for just about the weight of the rudder so that gives me 7oz to finish and still make 65oz.  It is a big plane with lots of power so a few ounces over is not going to temper my enthusiasm.

Ken

Maybe I got something wrong from your pictures, but if you add such a lever between the bellcrank and canard horn, doesn't it reverse the movement..?
I think you'll need a logarithmic gadget for the canard, too.
L

The Canard is driven by the opposite side of the bellcrank from the flap pushrod.  It needs to be reversed so that the canard moves in the same direction as the flaps.  The lever also reduces the movement.  When I first hooked it up I had over 40 degrees of movement.  5 - 15 is about all it will need.

If I wanted to build a whole new fuselage I would couple it to the logarithmic instead of the bellcrank.

Ken

This has been keeping me up at night.  First time twin and I have been told that the nacelles need to be as close to the wing as possible.  Don't ask me why because I don't know YET, I just trust the source.  So, by using state of the art reforming tools (Exacto #11), I reshaped the nacelles with the aft end of the motor 1/16" from the wing LE.  Nearly 1" closer. If this doesn't work I know where to send the bill.     I actually think they look better short.

Ken

Finally finished the reshaped nacelles and it was time to put them on the wing.  I didn't have much of a workbench, so I had to devise a method of mounting the nacelles that insured their alignment to the wing then mount the fuselage later.  First task was to get them in alignment with each other.  I used a variant of Bob Hunt's method and took a 2" x 18" x 1/4" piece of poplar and drilled holes on a centerline 14 1/4" apart.  This spacing will allow me to use a maximum of an 11" prop even though 10" is all I plan on using. I put a piece of 80 grit sandpaper over the holes.  Next I mounted both motors in the nacelles including the spinner backplate and mounted them to the poplar plank.  As I tightened them I was able to spin the nacelle over the sandpaper until I had a perfect spinner fit.  Now I have two nacelles perfectly aligned to each other.  Next I used the lost foam rib as a template and cut two stands that will act as a cradle for the wing. Using a Robarts incidence meter, I leveled the wing on my 18 x 32" "workbench atop my tools cabinet and sanded my way to a perfect fit.  Tack glued and remeasured it was still in aparent  alignment.  So the most dreaded and most critical task in building this beast is in the rear view mirror and thanks to Bob's advice to mount the plane to the motors, it may be done right.  Unfortunately beauty is not in the eye of the beholder when making a PA.  It is in the tracking of the plane when it flies. 

Ken

Starting to put it all together and I discovered another quad "P".  I put the timer in the same place it was in Endgame III, just in front of the wing LE where I could see the status light clearly. Well today I am checking alignment to tack glue the wing and guess what is blocked by the inboard nacelle.  So, I need a new place for the timer.  There is no place near the wing that will not be hidden by the inboard nacelle, so it has to be up front.  I have never put one so far forward so I will ask those who might now.  Will this work?

Finished installing the motor wires.  I probably used too heavy wire.  I used 16awg copper.  Got rid of all the slack to save weight.

Ken


 

If I understand correctly, then you can lengthen the sensor wire with a little soldering and get the length needed.  PM sent.

If I recall my history of the P38, the prop rotation direction was very significant. Ultimately they had to swap the engines left for right to get the correct flight characteristics. It might be something to research. As currently set up, it looks like you will have upwash over the tail making takeoff more difficult. Perhaps someone with actual twin experience can set this straight, as I am only talking theory.

Otherwise a marvelous project! Thanks for sharing. 🤠

Close enough to assembled and ready for filling in all the "oops" and "ah sh**"'s.  The paint scheme is now on the table.  I am thinking in two directions.  Treat it as military or civilian.  It has the general outline of a Beech Baron and there are several interesting paint schemes there.  Military is military.  Gray or white with lots of panel lines.  I want to use MonoKote as much as possible.  Has anyone used the "Dove Gray"?  How flat is it and will it take a clear coat?  The jury is still out on the mylar over polyspan.

Has anybody done a full finish for a competition plane using the mylar over polyspan?  I have done some tests and it appears to work but I have no clue how it holds up.  I have to have a light finish, the build ended up 4oz over budget.

Ken

No wonder you say "UGG", your numbers add to 110% to build!  I only do 100% on my builds, it takes less time!  I'm a Navy Vet, but how about a Marine (Dept of the Navy) throw back scheme with a bit of color?

Don

To Canard of not to Canard, that is the question.  On another thread there is a rather inciteful discussion of what may make the canard I have on Endgame II work and that was thrust vectoring.  Well where is the canard on Endgame 4 - In front of the props!  I pulled it once before I glued the nose cover on.  I can either pull it now or finish up to covering and fly it.

ken

Fly it!  You'll be forever curious about what might have been if you don't.

You are right.  Electrics don't make a mess!

Ken

I like the 2nd one, the Army Air Corp trainer styled one.

Steve

Today was a milestone.  Fully assembled with all electronics and wiring power up test!



It works!  I decided after investigating more to wire both ESCs to the power switch.  I like the old Air Corp trainer vs the new Navy one too.  Needs some refinement.

With it all glued together, no matter how hard you try not to, your mind starts to imagine paint schemes.  These are two that were suggested patterned after Navy trainers.  I am also thinking of something involving the flag of just gray with panel lines.

Everyone knows that yellow airplanes fly better.

I really like those big balsa fillets!  Looking good Ken!

Don