Author Topic: Pat King's E- Ringmaster Gyro. Build Report (Read 11557 times)

John Rist · « **on:** January 25, 2021, 03:48:49 PM »

I just ordered Pat King's E- Ringmaster Gyro. In an earlier post Pat wrote:

"I can do the Ringmaster Gyro as an electric airplane. I would design for the same power system as the Ringmaster Trainer III electric. That is an RSM25SYS using an RSM KDA A30-12M motor."

I have an electric S-1 Ringmaster. I plan to use the electric setup from this airplane. When the kit comes in I will take lots of pictures and do a build report and then a flight report. I am not sure why I would want to build one of these. But it's time to build something that serves no purpose except to have some FUN!

Say tuned. I will keep you posted.

John Rist · « **Reply #1 on:** January 29, 2021, 03:47:49 PM »

Just had a conversion with Pat Kin. I should get my E- Ringmaster Gyro kit next week. We had a discussion on correct CG for a Gyro. It needs to forward of the rotor blade mounting point. When I get the bird flying I will play with the CG to find the location that will provide stable flight and allow a loop. I think I will start with 58' to 60' lines. The Cobra motor I plan to use, a C-2221-12 will swing an APC 9x6 EP at 9,500 RPMs on a 3 cell LiPo pack. I think this should be plenty of power for this aircraft. Attached is a set of the planes. Of note is the way the motor is mounted. It is a rear mount setup with the rear shaft support by a ball bearing. Attached is a set of Pat Kings drawings.

Crist Rigotti · « **Reply #2 on:** January 29, 2021, 08:38:03 PM »

Neat project. Though I don't get the need for the rear ball bearing nor do I see the validity of the way it is mounted. Care to share with us as to the why's and how's? Thanks.

John Rist · « **Reply #3 on:** January 29, 2021, 08:55:32 PM »

Quote from: Crist Rigotti on January 29, 2021, 08:38:03 PM

Neat project. Though I don't get the need for the rear ball bearing nor do I see the validity of the way it is mounted. Care to share with us as to the why's and how's? Thanks.

There is a lot gyroscopic forces generated by the spinning motor when an aircraft makes a turn. The added bearing supports takes some of the load off of the motor mounts. I have never done this in the past so all I know about it is what I have read on this BB. As I said I don't have the kit yet, so I am not sure how it all works other that what I see on the drawing. When I build the kit I will take lots of pictures and show how the extra bearing is installed. It may not be necessary but what the heck Pat King has lots of experience in kit design and construction. If he incorporated it in into the design I bet it works. Stayed tuned I will bloviate all when I get the kit.

Crist Rigotti · « **Reply #4 on:** January 30, 2021, 07:25:03 AM »

Quote from: John Rist on January 29, 2021, 08:55:32 PM

There is a lot gyroscopic forces generated by the spinning motor when an aircraft makes a turn. The added bearing supports takes some of the load off of the motor mounts. I have never done this in the past so all I know about it is what I have read on this BB. As I said I don't have the kit yet, so I am not sure how it all works other that what I see on the drawing. When I build the kit I will take lots of pictures and show how the extra bearing is installed. It may not be necessary but what the heck Pat King has lots of experience in kit design and construction. If he incorporated it in into the design I bet it works. Stayed tuned I will bloviate all when I get the kit.

This thing isn't a regular stunter. Your hope is that it'll be able to loop. There can't be that many forces on it to warrant a rear mounted motor with an additional rear bearing support. Also the alignment will be critical. I'd just go with a rear mounted motor and skip that rear bearing support all together. IMHO.

John Rist · « **Reply #5 on:** January 30, 2021, 08:08:39 AM »

Quote from: Crist Rigotti on January 30, 2021, 07:25:03 AM

This thing isn't a regular stunter. Your hope is that it'll be able to loop. There can't be that many forces on it to warrant a rear mounted motor with an additional rear bearing support. Also the alignment will be critical. I'd just go with a rear mounted motor and skip that rear bearing support all together. IMHO.

All true However it appears that Pat has come up with an easy way to insure correct alignment and has built this arraignment into this kit. So it's not necessary but looks like a good how to learning experience for future use. I generally don't use rear mounted motors so this is new ground for me adding to the fun of it all.

John Rist · « **Reply #6 on:** February 10, 2021, 11:15:15 PM »

Pat said that he has shipped my E- Ringmaster Gyro. So, as the monkey said when he got his tail cough in the lawn mower: "IT WON'T BE LONG NOW" Stay tuned.

Package due 2-16-2021

John Rist · « **Reply #7 on:** February 16, 2021, 01:17:31 PM »

Well I guess I am having bad luck! Gyro due today but it no arrive.

Every body except the post office is out and about in this 2 flake snow storm we are having. Admittedly it is bad all around us but our zip code got very little ice. O well, should come tomorrow!

john e. holliday · « **Reply #8 on:** February 16, 2021, 03:41:38 PM »

Well it took over a month to get my kit from Pat because of USPS inept people they are now hiring. This is after he left it at the post office.

John Rist · « **Reply #9 on:** February 17, 2021, 12:27:27 PM »

Well my Pat King's E- Ringmaster Gyro arrived today. As always a very nice looking kit that is well packaged. Included is a fair amount of hardware. I guess the only down side is that that none of the music wire is bent. The full size drawing has all of the patterns to bund the wire. For me this is not a problem but if you have not bent music wire before it can be a little tricky.

John Rist · « **Reply #10 on:** February 18, 2021, 10:00:45 AM »

First step is to take the two ¼” fuselage halves and glue them together to make a ½” fuselage. The problem is to make sure cutouts in the two halves are aliened. In order to accomplish this I inserted the bell crank mount into its slot and placed a piece of scrap into the stabilizer slot. Glued with Titebond II wood glue making sure not to glue in the bell crank mount and scrap used for aliment. Pictures tell the story.

John Rist · « **Reply #11 on:** February 18, 2021, 04:03:23 PM »

Today I built the rotor tower. It is comprised of 6 pieces, two RM1, two RM2, one RM3, and the 1/8” music wire rotor shaft. As I stated earlier, none of the music wire is pre bent. With a ½” drill bit mounted in a vice, I headed the wire and bent it around the drill bit to get the required ¼” bend radius. After bending I cut it to length per the drawing. I then glued RM3 to one of the RM2 plywood mounts. I used this assembly to fine-tuned the bend in the music wire. It needs to fit the slot in RM3. Finished up by gluing the other RM2 and the two RM1 plates into the stack. Clamped it all together till the Titebond II wood glue dried.

Crist Rigotti · « **Reply #12 on:** February 18, 2021, 09:13:55 PM »

Nice!

John Rist · « **Reply #13 on:** February 19, 2021, 02:25:15 PM »

Getting ready to add motor mount and plywood side plates to fuselage. First step is to glue the two motor mounts together and drill to fit my Cobra motor’s X mount. Four 4-40 bolts and nuts provide the clamping force to let the Titebond II wood glue dry. Tacked super glued the X mount in place to use as a drill template.

Next is to assembly the 6 plywood pieces that make up the rear motor bearing support. The four pieces that are numbered 1-4 get sandwiched between the two side plates. They are a tight fit. Make sure they are well seated.

John Rist · « **Reply #14 on:** February 20, 2021, 08:29:22 AM »

Glue the Plywood side plates onto both sides. My workbench is covered with sheetrock. I cut a hole in the sheetrock to allow the fuselage to lay flat on the work bench. The motor mount protrudes into the cutout allowing weights to provide clamping force while the glue dries. The bearing mount and the motor mount are trapped in place by the plywood side plates. Install the plates on one side. Insert the bearing mount and the motor mount into their slots and then install the other side plate.

john e. holliday · « **Reply #15 on:** February 20, 2021, 12:01:17 PM »

This makes me want to dig my kit out and start assembling it. Of course it will be Glo powered.

John Rist · « **Reply #16 on:** February 20, 2021, 01:17:11 PM »

Stabilizer Elevator prep.
Located and marked the center line. Marked location of hinge. Number of hinges are not on the drawing but 6 looked about right. Cut slots for hinges using a Slot Machine. I beveled the hinge edge to allow free movement. I will round the leading and trailing edges before installing in the fuselage.

Every body has there own way of hinging, so whatever works for you is golden.

John Rist · « **Reply #17 on:** February 20, 2021, 08:41:23 PM »

Landing Gear
I changed up how the landing gear was shown on the drawing. The drawing shows a one-piece gear that has to be installed before the bell crank platforms are installed. I changed it to a two piece gear for three reasons. First of all a one-piece gear is hard for me to bend. The ½” section at the top of the gear is hard to deal with. Second I like to install the gear last. And third of all a two-piece gear is removable.

In bending a two-piece gear one side is slightly longer then the other to allow an over/under installation. It also requires drilling an extra hole for the under gear.

I secure the landing gear with lacing cord. This requires 4 more holes. I use 80 lb test kite line to lash the gear in place. A drop of super glue seals every thing making for a very strong setup. Spider wire will also work as the lacing cord. I temporally installed the gear for pictures. It actually will be installed last just before paint.

John Rist · « **Reply #18 on:** February 21, 2021, 11:26:27 AM »

Bell-crank Support.
The bell crank is located on the outboard side of the fuselage. It is supported by two plywood plates. A short one that only protrudes out the outboard side of the fuselage and a long one that also protrudes out the inboard side of the fuselage. The long support also holds the lead-out guide plate. A support brace goes under the long support. The bell-crank is supported by a piece of music wire. Some washers and a wheel collar centers up the bel-lcrank and locks it in place. Right now I have installed the bell-crank temporally. I will install the elevator and construct the push rod. After that I will remove it while I paint. During final assembly I will cut the music wire post to length and add the lead-outs.

John Rist · « **Reply #19 on:** February 23, 2021, 11:57:02 AM »

Stabilizer/Elevator.
Install the stabilizer making sure it is square and centered. One word of caution, make sure the stabilizer is not upside down. If installed upside down the rudders will cause the lines to go slack instead of keeping them tight. The drawing shows the top of the E-Ringmaster Gyro. Make sure the rudder slots are angled the same as the drawing when viewed from the top. Install the elevator with the six hinges. Install the elevator control horn.

I made up the pushrod with a 3/16" carbon fiber rod and two Okie Air thread pushrod Insert. I wrapped the rod ends with Spider Wire thread and then epoxy coated them. I installed the pushrod with a ball joint on the bell-crank end and a cleaves on the elevator end. Pushrod and bell-crank will be removed while painting the model.

John Rist · « **Reply #20 on:** February 23, 2021, 02:21:02 PM »

Installed tail skid, Bent it to shape per the print. Hammered the tip of the wire flat that is buried in the fuselage. Scuffed up the surface of the wire to give the epoxy some bite. Drilled a 1/16 inch hole and epoxied the tail skid in place.

John Rist · « **Reply #21 on:** February 23, 2021, 08:03:49 PM »

Added the two rudders. And yes they are angled in the right direction to keep the lines tight.

John Rist · « **Reply #22 on:** February 24, 2021, 02:16:16 PM »

Quote from: Ty Marcucci on February 24, 2021, 11:31:16 AM

Hi John. When it's ready to fly, let me know and I'll dig out mine and we can form the North Alabama gyro Squadron.

That is a good plan!!!

John Rist · « **Reply #23 on:** February 24, 2021, 02:17:38 PM »

Ready to Paint
Installed the landing gear. It is removable and is lashed in place with Spider Wire. I use a large carpet needle to accomplish the task. After all of the thread is are in place I sealed them with super glue. This makes an incredibly strong mount for the landing gear.

Sanded the rotor blades to shape per the drawing and installed them into the rotor blade hub. This hub sets all of the blade angles.

My E-Ringmaster Gyro is now ready for paint.

John Rist · « **Reply #24 on:** February 24, 2021, 09:40:03 PM »

What is a good starting point for the CG on a Gyro?

None of the electronics including the battery are shown on the plans. I am going to design and build a battery mounting platform. Need CG info to pick best place to mount same.

Crist Rigotti · « **Reply #25 on:** February 24, 2021, 10:22:00 PM »

Just forward of the rotor shaft? Doesn't Pat show this on his plans?

John Rist · « **Reply #26 on:** February 25, 2021, 08:44:13 AM »

Quote from: Crist Rigotti on February 24, 2021, 10:22:00 PM

Just forward of the rotor shaft? Doesn't Pat show this on his plans?

Thanks for the quick replay.

Looking at the plans posted at the start of this thread I don't see any CG info.

Crist Rigotti · « **Reply #27 on:** February 25, 2021, 09:12:10 AM »

Yeah, neither do I.

John Rist · « **Reply #28 on:** February 27, 2021, 10:40:48 PM »

Finished paint. Ready for motor and electronics. Will play with battery location to set CG.

John Rist · « **Reply #29 on:** March 02, 2021, 01:04:41 PM »

Ready for first flight (Almost!)
The motor and electronics has been installed: Motor - Cobra 2221-10, ESC - Tyrnigy Plush 30A, Battery – Hyperian 3S 1600, Prop – APC 9x6 EP. Total weight (with lead noise weight) is 31.5 oz.

Now for the bad news. I had to add 4.5 oz of weight to get the CG in front of the rotor hub. So right now the plan is to look through my collection of motors and ESC to see if I have a 4C setup that will fit. If I must carry extra weight it might as well be in the form of extra power.

Dave Rigotti · « **Reply #30 on:** March 02, 2021, 01:14:36 PM »

Did you go with the rear bearing support? On my Giro I have a 4S 2200, Cobra 2820. I had to move the battery way back to get it to balance where I thought was a good place. See "List your setup" in All Amp'd UP forum.

John Rist · « **Reply #31 on:** March 02, 2021, 04:38:31 PM »

Quote from: Dave Rigotti on March 02, 2021, 01:14:36 PM

Did you go with the rear bearing support? On my Giro I have a 4S 2200, Cobra 2820. I had to move the battery way back to get it to balance where I thought was a good place. See "List your setup" in All Amp'd UP forum.

No I did not use the rear bearing support. It appeared to be a bad ideal because it would make it hard to try different motors. Anyway, I am in the process of installing a 4S setup. I found in my junk box an OS Max electric motor that is no longer in production. It's probably way more power than I need. But with electric motors you can always use a smaller prop or reduce the RPMs. It remains to be seen where the battery will wind up. But as you said, one can always move it aft if noise heavy.

Thanks for you input. It lets me know I am headed in the right direction.

John Rist · « **Reply #32 on:** March 03, 2021, 09:20:35 PM »

Now really ready for first flight!!!
Motor is an OS Max OMA 3825-750, Prop APC 11x5.5 E, Battery is a 4C TP2800, ESC Trunigy Plush-32 40A, and timer is a KR. RPMs set at 9,000. Static amp draw is 17 A. Balance came out just forward of the rotor shaft without adding any noise weight. Timer is set for two minutes for the first flight.

This is one strong motor. It is capable of swinging an APC 12 x 6 E prop at 9K RPMs. I decided to go with the 11 x 5.5 as a start. Still feels gangbusters strong. Hopefully some good weather next week. Life has gotten in the way to do any test flying this week.

john e. holliday · « **Reply #33 on:** March 03, 2021, 09:49:37 PM »

I await the flight report.

Dave Rigotti · « **Reply #34 on:** March 04, 2021, 06:25:57 AM »

Is there a reason why the bell crank is mounted outboard on this electric example? Seems to be in the way of mounting the lipo battery?
Is it because it's a gyro? OR just a carry over from the glow powered setup that used a 3 line setup? Any experts out there that know why?

BTW... Looking good John!

John Rist · « **Reply #35 on:** March 04, 2021, 07:23:54 AM »

Quote from: Dave Rigotti on March 04, 2021, 06:25:57 AM

Is there a reason why the bell crank is mounted outboard on this electric example? Seems to be in the way of mounting the lipo battery?
Is it because it's a gyro? OR just a carry over from the glow powered setup that used a 3 line setup? Any experts out there that know why?

BTW... Looking good John!

I doubt there is a reason other than the designer of the model thought it was a good way to do it. It does make for an incredibly strong setup. And yes it did get in the way of mounting the battery however the motor and battery I used are larger than is needed. They are just the ones I have on hand.

pat king · « **Reply #36 on:** March 04, 2021, 08:09:17 PM »

The bellcrank is on the outboard side because it must be pulled through the fuselage to pull it out of the airplane. I pulled the wing out of a Rat Racer at 109 MPH. If the airplane could go 109 MPG dragging a pair of 60' lines and that wing how fast could it go without all the drag? Fortunately the engine quit after about 50 yards. Ever since then I am very much aware of the possibility of pulling a bellcrank or the bellcrank and wing out of an airplane.

Pat

John Rist · « **Reply #37 on:** March 05, 2021, 06:27:42 AM »

Quote from: pat king on March 04, 2021, 08:09:17 PM

The bellcrank is on the outboard side because it must be pulled through the fuselage to pull it out of the airplane. I pulled the wing out of a Rat Racer at 109 MPH. If the airplane could go 109 MPG dragging a pair of 60' lines and that wing how fast could it go without all the drag? Fortunately the engine quit after about 50 yards. Ever since then I am very much aware of the possibility of pulling a bellcrank or the bellcrank and wing out of an airplane.

Pat

I might of known there was a real reason. As I said earlier it makes an incredibly strong setup. Pat knows his stuff.

John Rist · « **Reply #38 on:** March 09, 2021, 08:00:29 PM »

Got some good news and some bad news. First the good news. The first flight of my E-Ringmaster Gyro was good! It got of the ground very quickly. Flew great. I had the timer set for two minutes. The KR timer burps the motor to let you know it’s time to land. When the motor quits it drops like a rock. It’s best to be close to the ground when the motor quits. Did not try a loop but line tension was good and she would clime and descend nicely.

I then set up my video camera on a tripod with plans to try for a loop. Well the torque of the motor flipped her on her side and it got ugly. The good news is that I was using Spider Wire lines which wrapped around the prop. The lines are toast so cheep is good. I did capture it on video.

Damage is minor. I will fix and try again. Going to do two things. I will add a music wire skid to the tip of the line guide and I will go to a pusher prop. The pusher prop should torque to the outside and all should be good.

Crist Rigotti · « **Reply #39 on:** March 09, 2021, 09:59:36 PM »

John.
Yeah the pusher prop will work better. Try setting your ESC to a slow spool up. That should help too.

John Rist · « **Reply #40 on:** March 09, 2021, 10:51:11 PM »

Quote from: Crist Rigotti on March 09, 2021, 09:59:36 PM

John.
Yeah the pusher prop will work better. Try setting your ESC to a slow spool up. That should help too.

Great suggestion. I will look into that.

John Rist · « **Reply #41 on:** March 11, 2021, 10:41:27 PM »

Repairs are made and ready for next flight. Looking at the video it looks like what happened was that the wheels got hung and it noised over. I have made 3 changes. First of all fatter wheel that role better. Second I have gone to an APC 12 x 6 EP cut down to an 11.5. No real reason for the cut down it was just a prop I had on hand. Big thing is that it is a pusher prop that should help with line tension. And third I have set the ESC to soft start.

Another thought is that I should start with a lot of UP elevator to keep the tail down on take off. Not looking for a 30 point take off. If it jumps into the air that is a good thing.

Looks like tomorrow or Saturday will be the next chance for grander or disaster.

john e. holliday · « **Reply #42 on:** March 12, 2021, 02:02:35 PM »

Well I see two big mistakes. No stooge to hold the Gyro. The other one is walking in front of the lines while going back to the handle. It could have been worse.

John Rist · « **Reply #43 on:** March 12, 2021, 11:08:08 PM »

Quote from: john e. holliday on March 12, 2021, 02:02:35 PM

Well I see two big mistakes. No stooge to hold the Gyro. The other one is walking in front of the lines while going back to the handle. It could have been worse.

#1 don't need a stooge with an electric. The handle is staked so that if the motor does start it will pull the down line aborting the whole operation. #2 you may have a point.

John Rist · « **Reply #44 on:** March 12, 2021, 11:29:12 PM »

OK flight # 2 went well. Take off is strange. It is dragging the tail-skid and bounces into the air. But once airborne it levels off and goes like crazy in just a few feet. It is fairly fast and responds well to the elevator. Line tension was great. I think the LH prop helped a lot. So far no guts to try a loop. But it looks like it is doable. Landings are short with almost no roll after touch down. This bird definitely flies on the pull of the prop.

Summery: The wood in the kit was great. It is a fast easy kit to build. I did not use the rear shaft bearing. Gluing a bearing down into hole that has no access if something goes wrong did not make sense. Also the current motor has no rear shaft. The only thing I would change in the kit is the direction the grain of the wood in the rudders. It should be vertical not horizontal. I bumped one of the rudders and had to glue it back on. I am sure the grain direction was controlled by the available location on a standard piece of wood.

It takes off weird, flies great and lands OK but you need to be close to the ground when the motor quits. This was a fun project. It serves no other purpose then to have fun and fun it is.

Crist Rigotti · « **Reply #45 on:** March 13, 2021, 06:50:15 AM »

Good for you John!

john e. holliday · « **Reply #46 on:** March 13, 2021, 01:10:29 PM »

Looks great. Need to dig out my kit.

John Rist · « **Reply #47 on:** March 13, 2021, 05:21:16 PM »

I watched the take off from my last video. I am quite sure that the rudders are hitting the ground causing the bounce. My tail-skid was too short. So I added a tail wheel and raised the back end a little. I test rolled it on my driveway. It now rolls smoothly and has a slight outward turn. Next takeoff should be smooth (I hope!)

Dennis Adamisin · « **Reply #48 on:** March 14, 2021, 06:18:39 AM »

Hi John

Cool project, way to go!

John Rist · « **Reply #49 on:** March 14, 2021, 11:46:28 AM »

In an effort to improve take off I added a tail wheel. Per the video the take off was better but still a little bumpy. But hay, it got off of the ground and flew. What more can you ask for from such a weird bird.

Lost a wheel during flight. However it still landed normal. It comes almost straight down when the motor quits. Landing was outside of the video view.

By the way, some safety concerns were raised about not using a stooge for take off. As I stated before a stooge is not needed for an electric if you stake the handle. If the motor starts before you get to the handle the stake will jerk the down line aborting the flight. Photo attached showing the correct way to stake a handle so it will pull only on the down line.