Author Topic: Endgame IV Build (Read 213690 times)

Mike Morrow · « **Reply #50 on:** May 30, 2024, 06:15:04 AM »

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

Ken Culbertson · « **Reply #51 on:** May 30, 2024, 03:34:44 PM »

I posted my flap "sealing" method in the open forum:

https://stunthanger.com/smf/open-forum/imbedded-flaps/msg673327/#msg673327

Ken

Ken Culbertson · « **Reply #52 on:** June 04, 2024, 06:06:02 PM »

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

Lauri Malila · « **Reply #53 on:** June 05, 2024, 09:53:22 AM »

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

Ken Culbertson · « **Reply #54 on:** June 05, 2024, 12:38:22 PM »

Quote from: Lauri Malila on June 05, 2024, 09:53:22 AM

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

Ken Culbertson · « **Reply #55 on:** June 25, 2024, 04:42:12 PM »

First pic of it all in one place. Almost half finished!

Ken

In case you are curious, or even if you aren't, the wing center section had to remain open to connect the rather elaborate control system and get all of the conduits for the wires going everywhere. So, I glued the wing to the bottom of the fuselage and left the top planking off. What I discovered doing it this way was having full access to the bellcrank with the wing glued into the fuselage is really cool. Regardless of bellcrank size I make all of my control systems to go from neutral to full deflection with 1 1/2" of leadout movement. That is 3" of wrist from full up to full down. With it finally assembled I got to see if it all worked. 3" exactly! Since I have a 5" bellcrank I was worried that I got the stops wrong.

Ken Culbertson · « **Reply #56 on:** July 10, 2024, 02:27:42 PM »

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

Ken Culbertson · « **Reply #57 on:** July 24, 2024, 06:59:29 PM »

Made a design change. Experimentation with the Canard on Endgame III has led to the need for different positioning and different control methods. Since this plane is intended to be my 2025 NATS plane I have decided to leave the Canard off.

Ken

Or not...I am rethinking my rethinking. The Canard was not intended to be the pitch control. It was to take pressure off of the handle and add stability (tracking). It accomplished both of those on Endgame III so maybe it stays...or not.

Ken Culbertson · « **Reply #58 on:** August 02, 2024, 07:17:49 AM »

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

Ken Culbertson · « **Reply #59 on:** August 02, 2024, 11:20:52 PM »

Today was fun if you like trying to remove parts glued in with JB Super Weld. I was testing my controls after installing the nacelles to make sure I didn't create a bind anywhere when I noticed how far back they seemed to be. I was marking the CG range that I wanted on the wing and about to position the leadouts about 3/4" behind that when I discovered that with the leadout guide fully forward I was 1 1/2" back from where they needed to be. That qualifies as a Quad "P". So I tried to figure how I had messed up and found the cause. As I mentioned in another thread the plane was supposed to have a GEO-Bolt wing but I changed it to a GEO-XL at the last minute. What I didn't so was change the tips. I used the same tip plan as Endgame III with the GEO-Bolt wing. So I ripped out the adjustable slider mount and repositioned it 1 1/2" forward and closed it back up. A little sanding and some filler and we are good to go. Well almost. The new angle needed to have it's path cleared for the leadouts.

Electrical wire came today. 16 gauge stranded copper. It is a little bit stiffer than the standard RC wire. These nacelles are cramped so I am making a mounting plate for the motor wires and cutting them back to about 1 1/4".

Ken Culbertson · « **Reply #60 on:** August 06, 2024, 10:46:36 PM »

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

Ken Culbertson · « **Reply #61 on:** August 17, 2024, 07:22:02 PM »

What do you call the correction for a Quad "P" when it doesn't work? A Quint "P"? Moving the timer to the nose caused it to too far from the accelerometer mount. Aggh.... So now it is back to it's original location but lower in the bottom hatch so that I can see it behind the nacelle. Wing is glued in. I used the Hunt method. Mounted the motors in the nacelles and used a 14" piece of 3/8" poplar as faux prop set. Fixed that in a fixture 90 degrees to the workbench then mounted the wing using my trusted Robarts meter. Works, thanks Bob. Slid the bearings onto the canard shaft and glued them in alligned with the wing centerline. Checked the control linkages and added the center sheeting. The fourth pix is the adjustable accelerometer pad mount. The spacers are silicone fuel line. With this pad design, stolen from Crist Rigotti, you can achieve perfect alignment of the pad. Starting to look like an airplane!

To continue the timer saga I put the props on the motors to see what it would look like and discovered that the timer start button was in the prop arc.

Moved it forward just enough to give me room to start it. Now the aft hatch hold down screw is blocked by the timer.

Scratch building has it's challenges!

Ken

Ah, the bellcrank - 5" dual sided to let me mount the canard. I needed to add the lever arm to allow the pushrod to be far enough away from the post then reduce it so that I only got 10-20 degrees deflection.

Fred Underwood · « **Reply #62 on:** August 17, 2024, 08:31:12 PM »

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

Ken Culbertson · « **Reply #63 on:** August 22, 2024, 05:38:33 PM »

Time to put everything together and see how it fits. Some does, some needs some persuading. 52 0z as it sits. Both motors, ESC's timer props and battery. All that is missing is the finish and wheels. It is conceivable I will make my 65oz target!

Ken

Larry Renger · « **Reply #64 on:** August 22, 2024, 06:47:20 PM »

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. 🤠

Ken Culbertson · « **Reply #65 on:** August 22, 2024, 08:22:51 PM »

Quote from: Larry Renger on August 22, 2024, 06:47:20 PM

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. 🤠

I worked allot with Mr. Twin, Bob Hunt in the early design. The nacelle spacing and inline setup as well as the wing have his blessing. He has commented that the prop rotation may need to be changed after it is flown. Super easy. Just swap in the ESC and swap props. Having the Canard in clean air will be interesting. On Endgame III the prop is in front of the canard.

Thanks for dropping by - Ken

Ken Culbertson · « **Reply #66 on:** September 06, 2024, 06:54:15 AM »

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

Larry Renger · « **Reply #67 on:** September 06, 2024, 07:29:54 AM »

My Rizngmaster is over 5 years old and the finish is fine.

🤠

Larry Renger · « **Reply #68 on:** September 06, 2024, 07:30:33 AM »

Quote from: Larry Renger on September 06, 2024, 07:29:54 AM

My Ringmaster is over 5 years old and the finish is fine.

🤠

Ken Culbertson · « **Reply #69 on:** September 09, 2024, 02:15:45 PM »

Plane is fully built and assembled that makes it about 50% finished. Sanding is the next 20% covering 10% and the last 30% finish - Ugg. Time to select a paint scheme. This is my sketchpad. Just to document the evolution I thought I would post the original design and what I actually built. I can't remember what made me decide to switch fuselages. I am afraid now that I am stuck with an USAF or Navy paint scheme.

Ken

Don Jenkins · « **Reply #70 on:** September 10, 2024, 05:04:08 AM »

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

Ken Culbertson · « **Reply #71 on:** September 10, 2024, 12:07:03 PM »

Quote from: Don Jenkins on September 10, 2024, 05:04:08 AM

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

Actually the numbers are understated. I just discovered that I glued in all of my pocket hinges too early and I have to drill them out and replace them. All for the best. I used too small a bushing and it all but guaranteed I would have an issue with the pull wire down the road. Beats me why, probably because I didn't have any brass at the time but I bushed them with aluminum. I like the Navy gray. My Father and little brother were Navy pilots. Me, I was Air Force ground crew. I may go with the USAF white. Yours is looking good!

Ken

Ken Culbertson · « **Reply #72 on:** September 11, 2024, 10:52:06 PM »

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

Brent Williams · « **Reply #73 on:** September 11, 2024, 11:39:35 PM »

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

Ken Culbertson · « **Reply #74 on:** September 12, 2024, 12:22:41 AM »

Quote from: Brent Williams on September 11, 2024, 11:39:35 PM

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

Ken Culbertson · « **Reply #75 on:** September 15, 2024, 03:58:48 PM »

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.

Steve Berry · « **Reply #76 on:** September 16, 2024, 02:31:49 PM »

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

Steve

Don Jenkins · « **Reply #77 on:** September 16, 2024, 02:52:49 PM »

I agree with Steve, the second one! Go Navy!!

Don

Ken Culbertson · « **Reply #78 on:** September 16, 2024, 05:36:53 PM »

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.

Mark wood · « **Reply #79 on:** September 20, 2024, 01:34:02 PM »

Quote from: Don Jenkins on September 10, 2024, 05:04:08 AM

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

Yes, but the last 10% takes 90% of the time.

Mark wood · « **Reply #80 on:** September 20, 2024, 01:36:40 PM »

Quote from: Ken Culbertson on September 15, 2024, 03:58:48 PM

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.