Working on Brakes

[Sv.grainne]

I'll give it a shot

 

[Tyger]

I'm not sure what your prop is like, but even half a degree of pitch change can make a significant difference. Make sure you have something that can measure that small an adjustment before you try it.

 

[Abid]

Abid: Severe pad wear and holding power at prerotation on first set. Modified with larger wheel cylinders, mtb pads, brake splitter. Much better but pad wear still excessive.
Will let you know how this modification works out. Engine idle set at 1500 RPM, tires 20 psi, prop pitch correctly set.

On a 912 or 912ULS your idle RPM should ideally be around 1700 to 1800 to reduce gear wear.
I have to ride AR-1 brakes quite a bit on taxi and I have taxi a mile each time. Use Matco brakes. I think we changed brake pads after reaching 500 hours. I usually allow it to speed up a bit and then apply brake and slow down quite a lot and then let go again.
You might want to reduce your tire pressure a little and see how that works but even in your situation brake pads should not wear that quickly.

 

[Abid]

My test was 5700 straight and level

You should look for 5600 to 5700 RPM on 912, 914 or 915 engine at Vy climbing not straight and level. S&L you may be able to go past red line at high speed because prop will be unloaded. If you are getting 5700 S&L fast, you may be only getting 5300 RPM at Vy climbout. That is at the edge of lugging the engine. These engines are made to cruise at 5100 to 5500 RPM all day long

 

[Sv.grainne]

I'm not sure what your prop is like, but even half a degree of pitch change can make a significant difference. Make sure you have something that can measure that small an adjustment before you try it.

I can measure to .1 degree. Will back off pitch some and try it. In the meantime, new stick completed with new master cylinder and Ray Allen grip.

 

[Tyger]

The brake control is on your stick?

 

[Resasi]

On the GyroTechnic VX1 and VX2 both brake levers, main wheels and rotor, are situated on the stick. It works very well and intuitive to use.

 

[Sv.grainne]

The brake control is on your stick?

Yes, throttle, rotor brake, prerotator levers to left side of cockpit in the Genesis.

 

[Kevin_Richey]

That "Ray Allen" grip looks comfortable. A change from previous stock grip w/ your Genesis?

 

[Sv.grainne]

That "Ray Allen" grip looks comfortable. A change from previous stock grip w/ your Genesis?

Yes, I added a trim motor and needed a grip that had up/down buttons and PTT switch for the radio. Ray Allen had the perfect solution.

 

[Tyger]

That "Ray Allen" grip looks comfortable. A change from previous stock grip w/ your Genesis?

It looks like you have to let go of a comfortable grip to engage the brake...

 

[Sv.grainne]

No, you still have the grip, I use 2 fingers on the brake when needed.

 

[Sv.grainne]

I got the new axles/brakes mounted this morning. Have not connected hydraulic lines yet, that's tomorrow.

My new Wheels/tires weigh 2.4 ozs each more than the originals so worst case I've added perhaps 3 lbs overall with the brake swap out.

 

[Sv.grainne]

New axles, wheels and brakes on, bled and tested. Wow, I was surprised at how well they stop/hold. Have not taxied yet, going to depitch the prop tomorrow, finish carb balance and double check everything.

Spliced in the new stick trim and PTT wiring, replaced an exhaust spring, set wheel camber and toe in just about ready for good weather!

I'll post some photos tomorrow.

 

[Eric S]

New axles, wheels and brakes on, bled and tested. Wow, I was surprised at how well they stop/hold. Have not taxied yet, going to depitch the prop tomorrow, finish carb balance and double check everything.

Spliced in the new stick trim and PTT wiring, replaced an exhaust spring, set wheel camber and toe in just about ready for good weather!

I'll post some photos tomorrow.

It's best not to mess with your prop. Seems like we had the prop set perfectly for proper RPMs in full-power climb and cruise RPM. If you depitch to try to adjust your taxi speed, it's going to overspeed in flight.

 

[Sv.grainne]

I'm only seeing about 5400rpm in full power climb so going to tweak down slightly. But I'm going to check full power climb next time I go out first. I also want to check my EMS rpm settings today. I have the warning bands set but did not write settings down.

 

[Resasi]

Bobby, up till now, on most take -offs, and regimes of flight I am only occasionally seeing the caution range on engine RPM. I am still cautiously exploring capability and performance.

As my confidence in the capabilities of the VX2 grow I will continue to explore and expand its envelope as we refine the Phase 1 period, and refine the POH.

It's an exciting time and as both your abilities confidence and experience grow you will be becoming one with your machine. Enjoy!!!

 

[Sv.grainne]

Leigh:

Understand, I want to verify my rpm warning settings.

 

[Tyger]

on most take -offs, and regimes of flight I am only occasionally seeing the caution range on engine RPM. I am still cautiously exploring capability and performance.

It's always good to be careful, especially when getting used to a machine, but takeoffs are when you actually want to be in the caution range for these engines. Rotaxes achieve their great power-to-weight ratios by being able to spin really fast. Max (rated) power is only achieved in the cautionary rpm range.

 

[Resasi]

Suppose it a hold over from using derated power whenever available...less wear and tear on the engine...but then, possibly a bit more on tires.