[Stock Helicopters & Turboprops] Non DLC Will Always Be More Fun!

[Gman_builder]

Just now, Azimech said:

I strive to keep a young heart and to develop the wisdom of an old man ... I already have the gray beard!

Words to live by bro. You live in Netherlands right?

[Azimech]

1 minute ago, Gman_builder said:

Words to live by bro. You live in Netherlands right?

That's right ... Which state do you live?

[Gman_builder]

Just now, Azimech said:

That's right ... Which state do you live?

Colorado. But I actually hate it here, my real home is in New Mexico.

Quick question. When cruising at a constant speed, is it more efficient to go with higher or lower pitch on the blades?

[Azimech]

1 minute ago, Gman_builder said:

Colorado. But I actually hate it here, my real home is in New Mexico.

Every place has got it's own charm right? What's wrong with Colorado?

[Gman_builder]

Just now, Azimech said:

Every place has got it's own charm right? What's wrong with Colorado?

Well I spent the better half of my life in Santa Fe, New Mexico. So when I moved to Colorado with my family I just didn't really fit into the lifestyle. The town I live near, Boulder, is mostly snobby, rich, ski-life, 420 blaze kinda people. Whereas Santa Fe is just really laid back and has a cool history with Native Americans and how they affected the culture in the area. It is just a place that really clicked with me the first time I went there. Similar to anyone whos been to Hawaii, its just the perfect place.

[Azimech]

14 minutes ago, Gman_builder said:

Well I spent the better half of my life in Santa Fe, New Mexico. So when I moved to Colorado with my family I just didn't really fit into the lifestyle. The town I live near, Boulder, is mostly snobby, rich, ski-life, 420 blaze kinda people. Whereas Santa Fe is just really laid back and has a cool history with Native Americans and how they affected the culture in the area. It is just a place that really clicked with me the first time I went there. Similar to anyone whos been to Hawaii, its just the perfect place.

Can imagine ... I've lived in this region all of my life but I'd love to settle in Slovenia. My girl is going to inherit the house some day ... it's in a mountain village with a lot of forest around it.

[Gman_builder]

3 minutes ago, Azimech said:

Can imagine ... I've lived in this region all of my life but I'd love to settle in Slovenia. My girl is going to inherit the house some day ... it's in a mountain village with a lot of forest around it.

Oh that's cool! I personally think the forest is kinda creepy. Usually eerily quiet and surrounded in dense vegetation. With no way to see whats around you. That noise in the distance could be from a squirrel or a Chupucabra. you never know. I guess that's part of the reason why I don't like CO. NM is a flat desert with all kinds of cool reptiles and stuff to look at.

Quick question, is it more efficient to run you prop at low pitch and high RPM or high pitch and low RPM to achieve a certain speed?

[Azimech]

3 minutes ago, Gman_builder said:

Oh that's cool! I personally think the forest is kinda creepy. Usually eerily quiet and surrounded in dense vegetation. With no way to see whats around you. That noise in the distance could be from a squirrel or a Chupucabra. you never know. I guess that's part of the reason why I don't like CO. NM is a flat desert with all kinds of cool reptiles and stuff to look at.

Quick question, is it more efficient to run you prop at low pitch and high RPM or high pitch and low RPM to achieve a certain speed?

In my experience it's best to look at three things: blade pitch, RPM and fuel consumption. For long distance runs I set a fixed speed with the autopilot, change the blade pitch a bit, look at RPM and observe fuel consumption. For example the last leg I'm flying at 90m/s and 2000m. to conserve fuel. I have the prop at -36, engine runs at 49.1 rad/s and fuel rate 0.56. If I change to -38 or -34, fuel consumption goes up so I know -36 is the ideal setting at that speed, at that altitude.

Generally speaking: low RPM is a bad idea in most cases. Interesting enough, when flying economy mode and limited speed, max RPM results in worse fuel consumption while slightly lower is the ideal setting. I think by chance I've built a very efficient propeller.

So a quick answer is not really possible. I make my assumptions during hours of testing.

[Gman_builder]

Just now, Azimech said:

In my experience it's best to look at three things: blade pitch, RPM and fuel consumption. For long distance runs I set a fixed speed with the autopilot, change the blade pitch a bit, look at RPM and observe fuel consumption. For example the last leg I'm flying at 90m/s and 2000m. to conserve fuel. I have the prop at -36, engine runs at 49.1 rad/s and fuel rate 0.56. If I change to -38 or -34, fuel consumption goes up so I know -36 is the ideal setting at that speed, at that altitude.

Generally speaking: low RPM is a bad idea in most cases. Interesting enough, when flying economy mode and limited speed, max RPM results in worse fuel consumption while slightly lower is the ideal setting. I think by chance I've built a very efficient propeller.

So a quick answer is not really possible. I make my assumptions during hours of testing.

Alright good to know. I just topped of the internal tanks on my Gremlin Mk3 without any modifications and it made it 250 km before the engine failed. I was cruising at 4,500 meters at 150 m/s consuming 1.8 units of fuel/s. definitely could do better, so I am modifying it now to hold more fuel, have less blowers, and more equipment for long distance flight. Like RTGs and whatnot that I didn't need when doing speed runs.

[Azimech]

16 minutes ago, Gman_builder said:

Alright good to know. I just topped of the internal tanks on my Gremlin Mk3 without any modifications and it made it 250 km before the engine failed. I was cruising at 4,500 meters at 150 m/s consuming 1.8 units of fuel/s. definitely could do better, so I am modifying it now to hold more fuel, have less blowers, and more equipment for long distance flight. Like RTGs and whatnot that I didn't need when doing speed runs.

I'm having the experience that ... unlike real life, flying lower results in lower fuel consumption.

[Gman_builder]

4 minutes ago, Azimech said:

I'm having the experience that ... unlike real life, flying lower results in lower fuel consumption.

I have found that too. But I think it is the altitude that matters. Fuel consumption(as well as thrust) decreases with altitude so you can fly for longer the higher you go, until you reach the service ceiling obviously. Plus, jet engines have a throttle curve where they have optimal efficiency and then it starts dropping off. I am assuming for Junos that curve is at a relatively low altitude and speed but its still there, so whoever finds the perfect speed and altitude will have better MPG than anyone else.

Here is the Gremlin Mk3 - B

Designed for endurance rather than speed, but it's still pretty good at the latter.

Complete Changelog:

 1. Reduced blower count from 80 to 56

 2. Lengthened wings and gave them a dihedral cant

 3. Added flaps for easier takeoff and landing

 4. Modified prop to perform better in high-expansion scenarios

 5. Added 2000 more units of fuel under the tail boom

 6. Lengthened tail

 7. Added quadruple redundant power generation system because I can

 8. Changed position of veins on the drive shaft for optimal power

 9. Added 1 extra battery to the prop pitch control system for longer endurance

 

 

 

[Azimech]

9 minutes ago, Gman_builder said:

I have found that too. But I think it is the altitude that matters. Fuel consumption(as well as thrust) decreases with altitude so you can fly for longer the higher you go, until you reach the service ceiling obviously. Plus, jet engines have a throttle curve where they have optimal efficiency and then it starts dropping off. I am assuming for Junos that curve is at a relatively low altitude and speed but its still there, so whoever finds the perfect speed and altitude will have better MPG than anyone else.

Those juno's ... the curve starts to drop off at sea level. It's therefore not very strange I set the speed record at sea level ... I assume best MPG will have the same result.

[Gman_builder]

Just now, Azimech said:

Those juno's ... the curve starts to drop off at sea level. It's therefore not very strange I set the speed record at sea level ... I assume best MPG will have the same result.

Ok that makes sense. When I did my run I achieved max speed of 253 m/s at 10 meters above the water so ya seems legit. What do you mean the best MPG will have the same result? You mean at sea level they are the most efficient? Well I guess that depends on how define efficient but with all jet engines the higher you go the better the MPG. Speed is also a factor though.

[Azimech]

15 minutes ago, Gman_builder said:

Ok that makes sense. When I did my run I achieved max speed of 253 m/s at 10 meters above the water so ya seems legit. What do you mean the best MPG will have the same result? You mean at sea level they are the most efficient? Well I guess that depends on how define efficient but with all jet engines the higher you go the better the MPG. Speed is also a factor though.

Jet engines achieve better MPG at altitude ... our turboprops seem to be a bit different.

Edited August 6, 2016 by Azimech

[Gman_builder]

Just now, Azimech said:

Jet engines achieve better MPG at altitude ... our turboprops seem to be a bit different.

True. I am trying to go as high as I can and doing some math to find out my range compared to a lower altitude.

So I was pretty much already at my max altitude. I was cruising at 4200 meters and my absolute MAX is 4250 meters lol.

It's performance was severely limited at those altitudes and it is much happier around 3300 meters. Now using less than 1 LF/S and maintaining 140 m/s.

[Gman_builder]

Should break 500 km this run. Definitely good. My personal record.

[Gman_builder]

Destination ahead! That makes about 470 km and I will have plenty of fuel to spare so I will keep going.

 

[Gman_builder]

Final number was 603 kilometers on internal tanks. Not bad.

Maintained a average of 140 m/s at 3300 meters. burning 0.9 LF/S

[The Optimist]

It seems attaching a variable-pitch propeller to the MKIII gives it a better acceleration and max speed. 

[Gman_builder]

1 minute ago, The Optimist said:

It seems attaching a variable-pitch propeller to the MKIII gives it a better acceleration and max speed. 

I told you

[The Optimist]

1 minute ago, Gman_builder said:

I told you

However, every time the engine reaches 22 rad/s, it violently explodes.

This is, of course, not beneficial to the operation of the motor

Edited August 6, 2016 by The Optimist

[Gman_builder]

1 minute ago, The Optimist said:

However, every time the engine reaches 22 rad/s, it violently explodes.

This is, of course, not beneficial to the operation of the motor

Better make a more capable engine then. Ours are operating at the limit right now of 51 rad/s. Get with it bro.

[Azimech]

6 minutes ago, The Optimist said:

However, every time the engine reaches 22 rad/s, it violently explodes.

This is, of course, not beneficial to the operation of the motor

You shouldn't install a helicopter engine in an airplane

[The Optimist]

1 minute ago, Azimech said:

You shouldn't install a helicopter engine in an airplane

The engine is ripped directly off a Curious Chakora v2

which I thought would be more suitable than the original PR-0P bearing

[Gman_builder]

Just now, The Optimist said:

The engine is ripped directly off a Curious Chakora v2

which I thought would be more suitable than the original PR-0P bearing

If you took it off the Chakora why is it exploding after 22 rad/s

Side note, I was experimenting with different prop designs and I found one that sustained 55 rads for a little while before the vibration tore the engine frame apart, the actual prop held up.