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Raptor Composite Aircraft

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Deuelly

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Seems he's replacing a lot of stuff for an airframe with 1/10 of a second of flight time.
Yes, but he's probably got almost 40 hours on the Hobbs so at least phase 1 is almost complete. Heck, let Justin take it around the pattern then start giving potential customers rides.:rolleyes:

Brandon
 
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Hot Wings

Grumpy Cynic
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"Tapered roller bearings need a fair amount of preload "

Looks like they are plain ball bearings:

Seems like a lot of drag from brake pads even if the seals are the type that tend to keep the pads in contact with the rotor.

Do aircraft brake systems ever use this type of piston seal, or residual pressure valves?

Wonder if he put the right fluid in the system?
 

BBerson

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Guess he read my brake dragging comment. :)
I would have pulled the caliper pistons out and cleaned the internal varnish off the cylinders that makes them stick.
Grob uses automotive DOT 3 brake fluid. They do stuff different in Europe.
 

donjohnston

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My favorite was where he moved the static port to inside the cabin... on a plane that's going to have a pressurized cabin!

You can't make this stuff up.

But even if the cabin isn't pressurized for the first flight, he could see some interesting pressure variations in that cabin.
 

jandetlefsen

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Is it just me or does the new brake setup still seem to drag the pads on the discs so they will start glassing again right away? Is this really how "spin freely" look like on a plane? Also can you not just slightly sand off the pads to remove the glassing? I do that on my mountain bike all the time, admittedly i don't know **** about planes.
 

BBerson

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A bunch of VFR airplanes have static in the cabin. Not an issue till flight test determines a best location.
It's not a mountain bike. This first flight may need optimal brakes.
 

Malish

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A bunch of VFR airplanes have static in the cabin.
In most aircraft static port in cabin - alternate static pressure source, as main(outside aircraft) port is clogged or frozen. In most aircraft pressure inside cabin is lower in flight or hi speed taxi. Because of that Raptor airspeed indicator and altimeter will show incorrect readings.
 

ScaleBirdsScott

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Honestly I'd just as soon get one of those new standalone all-in-one pitot systems that bluetooths to a tablet for independent of on-board systems monitoring. The BOM or Wingbug or similar. Maybe run both. That way at least if the onboard system does have some bias or error there's a greater chance of having multiple points to reference. And they can all record data, maybe even stream it? Of course if those devices have their own biases and inaccuracies then they aren't going to be as much use; but then you can check those in flight using a known good aircraft.
 

cheapracer

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Likely nothing wrong with his old brakes, waste of time and money replacing them.

Glazing, which for the cure is no more than some sandpaper and elbow grease, or a nice bit of flat concrete or take them to a brake shop for a light skim, same with the pads (as long as they aren't cooked), has nothing to do with dragging, other than the dragging causing the glazing.

95% of the time dragging comes from improperly adjusted pushrods from the pedals to the master cylinders, and the other times it's swollen caliper piston seals, though this rig isn't old enough for that, or rarely, a restriction in a brake line such as a kinked rubber hose.

One other small possibility is some master cylinders have a restricted return valve to help prevent pad knockback.


Wonder if he put the right fluid in the system?
Too much fluid in the master cylinders can also cause it, not many are silly enough to do that though.
 

TFF

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That plane has a lot of brakes. Floating disk on something that small and all that break pad area. He has enough brakes for a 6000 lb plane, oh yea I forgot.
 

Victor Bravo

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Wait a minute... did someone say that he moved the static port to inside the cockpit on a pressurized aircraft? If that is true, I think we need to talk more about that and quit worrying about a little bit of dragging brakes, no?.
 

cheapracer

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Yes, he did, but aircraft is not pressurized for now. And where he get the air for cabin pressurization? From engine intake turbo?
That makes me wonder what would happen if a turbo seal blows, which is not unusual for a turbo, will the cabin immediately fill up with unsurvivable choking oil smoke?

I don't know enough about turbos to be sure, but I have seen hundreds of turbos blow their seals, it's not pretty.

Read the text :
Driving down Ferrers rd Eastern Creek I see this belching cloud of smoke in SMP driveway so I pulled over to get a video and see if I could help out. Not only did SMP fireys show up but NSW fire brigade were also alerted. The trucks turbo had a blown seal allowing engine oil to get pumped into the inlet. As diesels run on anything the engine could not be turned off.

 

Hot Wings

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not many are silly enough to do that though.
Think about that for a moment. :rolleyes: He didn't get instructions from the manufacturer about bedding in the brake pads, and didn't. Maybe they also didn't supply fluid specifications? Even if they did....."I'm good with that. Fluid is fluid".

Seen plenty of ground vehicles vehicles with dragging brakes because the owners put in power steering fluid that swelled the caliper piston seals and/or the brake lines. Here in the US it was a very common problem with old Austins and MGs.
 

pictsidhe

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There are fluids for each type of seal. Using the wrong brake fluid can wreck all the seals. The wrong oil went in the shocks, maybe Peter picked the wrong brake fluid. I'll going to third the notion that the cure for dragging brakes is not pads and discs. Maybe they are needed, but they didn't cause the problem and won't cure it either.
 

VP1

Todd C.
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In the latest video Peter learns about breaking in brake pads.

His videos would be more entertaining if Ron Howard were narrating
 

TFF

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The plane can’t be pressured with the big crack in the side glass. This plane will never be flown pressureized as is. Hopefully he has locked the outflow valve open for safety. Runaway pressurization is not good in a lot of ways.

If it gets far enough to calibrate the pitot static good for him. His test guys can do the drag funnel calibration like they have done on other test programs. They have a video. Numbers being off and understanding trend of numbers are all a part of testing. That he cares enough without calibration means he wants numbers to be pretty.
 
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