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10/23 Raptor Video

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gtae07

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its why we still fly behind 1940's engine technology
Well...

There have been significant improvements in piston engine technology since the 40s, especially in overall efficiency and reliability. Just go to any new car dealer today to see it in mass production quantities.

Light aircraft still generally fly behind 40s technology because developing and certifying improvements is expensive, and has only gotten more so. At least in the 40s and 50s, a lot of tech and knowledge could "trickle down" from work on big air-cooled engines used on transports. When the turbine engine came along and essentially replaced piston engines on everything it was economical to do so, much of the funding for aviation piston engine development dried up.

The later automotive-derived improvements like variable-timing electronic ignition, electronic fuel injection, etc. are stunningly expensive to certify, in large part because the applicable cert requirements were written to the needs of advanced-technology engines for airliners and ETOPS, and IMO are very much overkill for the needs of light aircraft. Plus, many potential improvements might be incompatible with leaded fuel (and we all know how well the unleaded fuel program is going), or require liquid cooling (a pain to integrate on airframes optimized for air cooling, or expensive to develop new airframes). With an anemic market barely holding on, nobody has the cash to burn to make something new and nobody wants to pay the massive premium to buy one unless they can amortize the cost in a commercial application (see diesel trainers).
 

PPLOnly

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All done checking for oil leaks via test-flight. Definitely couldn’t accomplish that on the ground.

I’m hoping the new cooling modifications continue working in the summer.
 

berridos

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Very educational those ropes at the tips to show the tip vortices. Lovely to see vortices in reality and how stable they are (and not cfd). How should be those lines, out of what material and thickness?
Would love to see these lines attached to th eleading edge of a facetmobile to visualise vortex at mid span. Would it be feasible? In fact i am thinking of a test programm to monitor the vortex on rc prototypes with these devices.
 

wsimpso1

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I’m hoping the new cooling modifications continue working in the summer.
All temps observed will increase or decrease with ambient temperature. The engine makes heat, and heat is rejected to the ambient air. If any system has an open thermostat and is right at borderline at 50 F, he will be 50 F overheat when the ambient temp is 100 F. That's how it works...

Billski
 

rbarnes

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"I'm quite happy to run the engine up to 250 in the climb"
🤦‍♂️

another 15 lbs in the back ? talk about weight creep. He must have added a 100 lbs or more to the plane since the last time he weighed it.
 

Vigilant1

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In the equations for forced convective heat transfer, one of the terms is the difference in temperature between the hot surface (in this case, the "radiator" fins) and the air traveling by it. That difference is a lot smaller with a radiator than with the hot fins of an air cooled engine. That's why, all else being equal, a marginally adequate liquid cooled engine is more adversely affected by high OAT than a marginally adequate air cooled engine will be.
 

PPLOnly

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All temps observed will increase or decrease with ambient temperature. The engine makes heat, and heat is rejected to the ambient air. If any system has an open thermostat and is right at borderline at 50 F, he will be 50 F overheat when the ambient temp is 100 F. That's how it works...

Billski
I was joking. He’s celebrating great success in cooling while never acknowledging he’s flying during the winter and that’s most likely the bulk of the improvement he is seeing.

I’m trying to imagine a takeoff and climb on a typical Georgia summer afternoon after a fly-in hamburger where you showed off your F-16 touchdown speed to all your friends.
 

Victor Bravo

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Earlier in the January 15 video I noticed what appear to be black Ty-Raps/zip ties in the engine compartment.

On a lower temperature engine (one where you don't need heat shield material and are having temperature problems) some of that may be tolerable. But on a high horsepower, high-heat engine in a tight cowl, I don't think it's wise.

I also noticed several saddle/bolt clamps and U-bolts that seemed to have a lot of extra threaded bolt sticking out past the nut.

Anyone else notice these kinds of little eyebrow-raisers in his videos?
 

wsimpso1

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Anyone else notice these kinds of little eyebrow-raisers in his videos?
Yes. I suspect most of us are either picking our battles or suffering from fatigue over the plethora of issues. Somehow, threads sticking out and zip ties that may come adrift seem like small fish when the turbos are choked, the intake and exhaust temps are too high, power has to be kept at 40-50% to prevent overheat in winter, the PSRU seems bent on self-destruction, and the plane oscillates around continuously in at least two axes.

Billski
 

Pops

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Earlier in the January 15 video I noticed what appear to be black Ty-Raps/zip ties in the engine compartment.

On a lower temperature engine (one where you don't need heat shield material and are having temperature problems) some of that may be tolerable. But on a high horsepower, high-heat engine in a tight cowl, I don't think it's wise.

I also noticed several saddle/bolt clamps and U-bolts that seemed to have a lot of extra threaded bolt sticking out past the nut.

Anyone else notice these kinds of little eyebrow-raisers in his videos?
I also noticed those things. But as Bill says, you start at the top of the list and get the more important things first. Long list.
I don't understand how an oil temp of 245 degs is OK and summer is not here yet.
 

PPLOnly

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Bit like buses, bugger all happens, then 2 arrive together🚌🚎


Just noticed on yesterday's video that PM stuck a thermometer on the fuselage with tape !!!!! 'On a Pusher', seems like a good idea. Bang, what the 'F' was that ?
106 knots on final approach. Faster than some Citations. All the temp stuff is fine, why doesn't he find out how slow his plane can fly so he can dial back the speed some? Let's pretend for a minute all other issues are fixed, this isn't a plane I'd be comfortable flying coming over the numbers that fast.
 

Kyle Boatright

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106 knots on final approach. Faster than some Citations. All the temp stuff is fine, why doesn't he find out how slow his plane can fly so he can dial back the speed some? Let's pretend for a minute all other issues are fixed, this isn't a plane I'd be comfortable flying coming over the numbers that fast.
Think about the inevitable engine out. Yeah, I know it has a parachute. But that's only good above a certain altitude. I'd hate to be the guy coming in at 100 mph to make an off-field landing with only a carbon layup between me and my maker.
 
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