Scale RCM 1/3 Scale Champ Build

Snoopy1 said:

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Tony take a good look at this picture do you think you have your temperature probes in the correct location. From what I read I think you have them to high up on the cylinders

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Now that the CH Ignition will be installed this will free up two temperature sensors, have any idea where to place them and what an alarm might be? I used 290f on the cylinder based on 2 stroke experience but I don't know if that carries over? On the head the intake is on one side while the exhaust is opposite, I would guess under the spark plug is good but due to recess don't think it is possible. The thermography photo showed 90C on the exhaust, not very hot at all?

Ok Tony I have not ever done any experiments between 2 and four stroke engines. But what I do know temperature limits are dependent on piston and barrel metallurgy. And the one that really dictates maximum operating temperature is the piston. For most of the engines we use 300 (air cooled) is the maximum. This gets really complicated on how piston temperature relates to barrel fin temperature. The most important thing from work I did many years ago does the temperature stabilize at full load if it keeps going up changes need to be made. When doing some of this work we would have five identical engines same conditions and we would see 20 degree variance.

From the Roto website;

• Crank case (kit) – it is rough-worked of the cast at the CNC milling cutter. After that it is covered or slashed with a special colour.
• Cylinder (roll) – it is made of one piece of dural with pressed insole from the mild-granular cast iron, it is sharpened and honed to the correct size.
• Piston – it is casted from silicon alloy with one sealing circle. The aparature for the bung 8 mm is honed.
• Piston rod – it is forging, which is completely worked. Two needle focuses are moulded into piston rod, it is made for the piston and cranked bung.
• Crank shaft – it is made of one piece of steel, it is cemented and hardened and it is completely sharpened.
• Back lid of the engine – it is worked casting, in which is hardened and sharpened rolled slide - valve layed.

Have any thoughts about the above?

I used the tin from an empty gallon can of WD40 to make the straps for the seat backs and had some left over so that's what I used to make the control rod mounts. Since it is covered with the boot there was no need to sand the printing off the tin. As I worked with the printed metal it took me back to my childhood days of pressed metal toy cars for Japan. It forms nice and easy and does the job and only costs a little blood to extract. Still waiting for the aluminum balls from McMaster to finish off the rods, tracking says it will be delivered today.

I made revisions to the mounting angle and position of the sticks based on photos I found while researching the throttle plates. I did find the throttle plate photos on Ebay and working with someone to CNC engrave two to mount under the throttle knobs.
Based on the original running of the engine I increased the size of the fuel tank by a small amount. I had originally installed a half liter water bottle, didn't take much effort to empty the tank running a low power in the back yard. Increased the size to 20 ounces and will closely monitor consumption on first couple of flights. I don't mind topping off every flight.

The batteries are mounted under the front seat along with the ZEPSUS switches. The switches have a 15 amp rating as well as a burst rating of greater than 30 amps and tested at 20 amps for 30 seconds. I'm pretty sure two will get the job done, heck there's only 4 D945 servos on the surfaces, even with all four stalled there is still margin. The switches have the green indicating light when switched on.
There's a R8 PRO receiver mounted under the back seat, this receiver has a M+ receiver connected to the SBUS IN for redundancy, the M+ is mounted in the top of the cabin area. The R8 PRO along with a R4 mounted in the top of the cabin area are the two control inputs to RB10 redundancy bus.

I fly the same way. R8 pro with a M+ and a RB10. Never let me down.

The interior of your cub looks perfect!!

Rick,
Have you given any thought to the R10 PRO? Dual XT-30 plugs.

TonyHallo said:

Rick,
Have you given any thought to the R10 PRO? Dual XT-30 plugs.

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I have purchased XT-30 plugs and will be changing over to them slowly really like them

TonyHallo said:

Rick,
Have you given any thought to the R10 PRO? Dual XT-30 plugs.

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I really like it. By mistake I bought archer SR10 pro, the one with the gyro built in. The gyro in it is a real PIA to set up so I just went with the archer R8. My next purchase will be a R10 pro.