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

[Majorjim!]

Just now, seiryu said:

It's pretty small. Right?

It's huge!

 Nah, good work matey.

[Azimech]

5 hours ago, seiryu said:

well,I made a small 20 parts electrolic prop.

It's pretty small. Right?

I admire your compact design but I think more people will like it over here:

 

Development update, my Focke Wulf Fw 190-A4. Another major redesign. Click the album for picture descriptions.

 

Edited March 26, 2017 by Azimech

[Azimech]

For anyone having problems getting good performance out of your turboprops, here's a short list of do's and don'ts.

1: Don't use rigid attachment anywhere on the turbine shaft, this limits max engine RPM.
2: Don't use Kerbal Joint Reinforcement for the same reason.
3: Make sure your engine is capable of operating near 50 rad/s and keep it operating at those speeds. Unfortunately 50 rad/s is also near the physics redline so you need to watch your engine speed closely at all times.
4: Use a variable pitch propeller.
5: A larger diameter turbine means more torque.
6: Make use of the fact parts radially expand from the turbine shaft at speeds >30 rad/s. Build a stage for starting the engine, another stage that kicks in at 35 rad/s, these blowers start hitting the colliders of the turbine blades.
7: Try to build a stock fairing around your engine. All parts inside will be shielded and produce no drag. No airflow for cooling either so you'll need to build a cooling system as well.
8: Use Kerbal Engineer or V.O.I.D. for the ability to read engine speed.

 

Example turboprop with multi-stage blowers: https://kerbalx.com/Azimech/77I-Azi12-Curious-Chakora-v31

Example turboprop with a stock fairing and cooling system: https://kerbalx.com/Azimech/77I--Azi19-Jolly-Jinn

Edited March 26, 2017 by Azimech

[Azimech]

If anyone needs a new challenge, try the FAR dev build. It makes building turboprops both more easy and more difficult.

I've made a FAR version of the Curious Chakora. It flies fine :-)

[MiffedStarfish]

@Azimech sorry I'm not sure if this is the right thread, but I just built a helicopter that is for most part flying properly, however it pitchs up slowly after takeoff. I have checked everything I can think of, it's not col or com, and I have enough control surfaces so I'm assuming it's something to do with the fact it's a helicopter and not a VTOL. As you seem to have the most experience with Stock helicopters, I was wondering if you knew anything about this or encountered this problem building your in your builds? Once again sorry, I know this is your showcase thread but I couldn't find any trouble shooting style Stock helicopter threads.

[EpicSpaceTroll139]

2 hours ago, MiffedStarfish said:

@Azimech  I just built a helicopter that is for most part flying properly, however it pitchs up slowly after takeoff. I have checked everything I can think of, it's not col or com, and I have enough control surfaces so I'm assuming it's something to do with the fact it's a helicopter and not a VTOL. <Snip>

Is it pitching up while just hovering or while moving forward?

If the latter, you are likely experiencing something called dissymmetry of lift, which is when the advancing rotor blades are moving faster through the air than the retreating blades, and thus getting more lift. Due to gyroscopic precession, this can manifest itself as the helicopter trying to pitch up as forward airspeed increases. 

If it's happening during hover, idk what's causing it, but either way, moving the rotor backwards slightly should help.

[MiffedStarfish]

@EpicSpaceTroll139 Ok that would probably explain it. I don't know helicopters.  due to the way it's built, instead of moving the rotor backward I am going to add a small open section directly in front of the bearing assembly. Thanks for the advice! 

[Azimech]

16 hours ago, MiffedStarfish said:

@Azimech sorry I'm not sure if this is the right thread, but I just built a helicopter that is for most part flying properly, however it pitchs up slowly after takeoff. I have checked everything I can think of, it's not col or com, and I have enough control surfaces so I'm assuming it's something to do with the fact it's a helicopter and not a VTOL. As you seem to have the most experience with Stock helicopters, I was wondering if you knew anything about this or encountered this problem building your in your builds? Once again sorry, I know this is your showcase thread but I couldn't find any trouble shooting style Stock helicopter threads.

No problem, anyone can post their creations here and ask questions/discuss. 

What EST139 said is correct, personally I choose to have the CoM in front of the CoL to counter the effect. All of my helicopters have this.

[MiffedStarfish]

@Azimech I just finished a 2.0 variant of my helicopter whitch fixed that problem by adding a new section inbetween the rotor assembly and the cockpit and by replacing the rear jet whitch counteracted the spin with a small tail rotor. Thanks for the help, I'm pretty happy with how it turned out especially since it's my first helicopter. 

 

[Azimech]

News: Eric Johnson Space Administration (EJ_SA) has built the first prototype turboshaft helicopter with a working swashplate and cyclic/collective. I myself didn't believe it could be done with stock parts.

https://www.twitch.tv/videos/135398742

It lifts off at around 6:00.

@EJ_SA ... you're awesome!

[Castille7]

1 hour ago, Azimech said:

News: Eric Johnson Space Administration (EJ_SA) has built the first prototype turboshaft helicopter with a working swashplate and cyclic/collective. I myself didn't believe it could be done with stock parts.

https://www.twitch.tv/videos/135398742

It lifts off at around 6:00.

@EJ_SA ... you're awesome!

Couldn't catch it live, but this was really awesome!

[Majorjim!]

8 hours ago, Azimech said:

News: Eric Johnson Space Administration (EJ_SA) has built the first prototype turboshaft helicopter with a working swashplate and cyclic/collective. I myself didn't believe it could be done with stock parts.

https://www.twitch.tv/videos/135398742

It lifts off at around 6:00.

@EJ_SA ... you're awesome!

I've seen a few of these already. Does his fly?

[MiffedStarfish]

Barely, it skims along the ground. 

[Azimech]

After having completed 4 helicopters this week and someone on Reddit asked "No coaxials?" yesterday, I hacked together my first coaxial in 1.5 years this morning in just 30 minutes.

I just stacked two Asura II engines on top of each other. The prototype isn't exactly pretty nor fast but has a good endurance and is very strong. The biggest plus is that the engine is incredibly reliable and can take heaps of punishment, you can even fire a cannon at it and it keeps working.

The helicopters I released this week:

 

 

 

The big breakthrough appears the scalability of the Asura II engine. Azi27 Dione uses just 10 blowers instead of the usual 50, making this little heli my first with less than 100 parts while still having the tank like reliability of the bigger ones. I've even tested one with only 5 blowers but that one needs a lot of work.

Not trying to compete with @klond because we all know: he's the champion building light engines. I could never touch him.

[MiffedStarfish]

@Azimech Those look great, I really want to see you fire a cannon at one of them now. How many blowers do you think I should use? I was thinking 2 panthers. My helicopter is going to built with mk3 parts, but not too big. Also, I love your use of crew cabins in the rotor assembly, have you ever flown them with kerbals in it? 

Edited April 15, 2017 by MiffedStarfish

[Castille7]

I love the sleekness of this one (77 Industries Azi26 Lelantos) looks amazing!

[Azimech]

1 minute ago, MiffedStarfish said:

@Azimech How many blowers do you think I should use? I was thinking 2 panthers. My helicopter is going to built with mk3 parts, but not too big. Also, I love your use of crew cabins in the rotor assembly, have you ever flown them with kerbals in it? 

I'm not a fan of the Panther, the static thrust is to weak in dry mode and the fuel consumption goes through the roof in wet mode. I always choose Juno's. You need more of them but they're pretty light and a lot shorter which makes for a more aesthetic solution (although @EpicSpaceTroll139 has some very pretty designs using them).

I haven't put kerbals in the turbine shaft.

You sadist.

[MiffedStarfish]

It would be efficient! It would be a two in one training centrifuge and rotor, it would save money! 

[Azimech]

The good old days ... two years ago.

 

And before Squad reworked the fuel flow system, I needed a web of fuel lines in some of my airplanes. I actually miss that.

 

My engines were a lot less reliable back then. But they failed in awesome ways.

 

Sometimes I would just throw a ball at them for the effect. Never released that Corsair. Wish I did.

 

 

My very first turboprop had the amazing top speed of 25m/s. During a test flight something did "poof" in the left engine and released a puff of smoke. It continued to run but with a wobble. Fantastic.

 

Edited April 15, 2017 by Azimech

[klond]

On 4/14/2017 at 5:36 PM, Azimech said:

News: Eric Johnson Space Administration (EJ_SA) has built the first prototype turboshaft helicopter with a working swashplate and cyclic/collective. I myself didn't believe it could be done with stock parts.

https://www.twitch.tv/videos/135398742

It lifts off at around 6:00.

@EJ_SA ... you're awesome!

 I don't know what to say.. That is awesome.  Glad you showed us this.  Gives me renewed ambition to keep going and see what we can do.

---

For a week or so I've been trying to make that Russian contra-rotating 4 engine plane, the Tu-95.

Here's the story:

 Didn't want to go mk3, so decided to do mk1 to stay lighter and more aerodynamic.

 I already had a little counter rotation helicopter so I spend a few days trying to stuff that engine it into a structural fuselage.  I don't know why I thought I could make a turbo plane fly in this soup.  'Guess I forgot how challenging it really was.  I did learn a few things though.

 Building replicas ain't easy, and I'm not proud enough to post the craft file but here's the result.  It ain't great.  I blew 90 percent of my time budget on the engines.

Spoiler

 Hitting 50-70m/s on the runway was fine.  On some builds with tons of Junos, weight held me down (64 engines with smoke turned on sucks BTW).  Other lighter builds with less Junos it lacked power.  More blades meant more drag.  Longer blades meant really tall landing gear, spacing issues.  Every improvement was met with a new resistance.  I mean, I knew this right, but I spend a week stubbornly relearning.

 The plane that actually flew had 2 extra Juno's on each nacelle as the "exhaust.."  I don't know how much the exhaust on the real plane helped with propulsion, but these 8 junos were doing a majority of the work and it didn't feel right.  (landing gear in wrong positions on this pic- for testing)

 Even though the plane ain't great, I think the engines were a success.  They spin fast and hold up well.  There's just no getting around that small diameter = low power.  I just didn't want to believe it.

 Here's the file for one of the nacelles.  https://ufile.io/9yp7t   @NorthAmericanAviation wanted to see it.  

 I think the best thing I learned is - if the center of the tip of the Juno is inside the outer skin of the structural fuselage, it blows inside.  Same for panther I think.

 Bearing is an antenna in 4 solar panes.  Wheel is empty RCS tank.  If bearing gets wonky I add RCS fuel to tank to add mass.  'Used Vernor engines to increase the radius of the blower wheel for power and they have a high heat tolerance (angled a little so they don't scrape the inner wall).  There's an octo2 stuffed in there on hibernation to change blade pitch (action button 1).

 I used the lil cubic boxes on earlier version, but more than 4 engines overheats them.  Here you can see a different bearing that worked ok.

 Not sure I'll try another replica for a while.  Gut punch to the ego hurts but I'm still going strong.

 

Edited April 17, 2017 by klond

[Azimech]

Yes, I feel your frustration @klond.

If only the speed limitation could be lifted, 477 rpm is incredibly low. Your engines would be fine if the props could run at 2500 - 3000.

[EpicSpaceTroll139]

On 4/14/2017 at 6:36 PM, Azimech said:

<snip>

https://www.twitch.tv/videos/135398742

It lifts off at around 6:00.

@EJ_SA ... you're awesome!

I tried watching and since I couldn't skip ahead by sub-10-minute long increments, I had to watch from the beginning. All I got was the "starting soon" thing for 6½ mins. I then skipped around through some of the 9+hr (!) stream and didn't find KSP anywhere? I want to see this magical flying machine too.

Edited April 17, 2017 by EpicSpaceTroll139

[Azimech]

13 hours ago, EpicSpaceTroll139 said:

I tried watching and since I couldn't skip ahead by sub-10-minute long increments, I had to watch from the beginning. All I got was the "starting soon" thing for 6½ mins. I then skipped around through some of the 9+hr (!) stream and didn't find KSP anywhere? I want to see this magical flying machine too.

It's really there, 6 hours into the stream. Maybe something with your browser? I use Firefox/Windows 7.

[EpicSpaceTroll139]

8 hours ago, Azimech said:

It's really there, 6 hours into the stream. Maybe something with your browser? I use Firefox/Windows 7.

There's the problem...I thought you meant 6 minutes xd. Must have missed it while skipping around.

Edit: I love his reaction lol!

Edited April 18, 2017 by EpicSpaceTroll139

[klond]

 Maybe it's been done before but

 I saw jfrouleau on kerbalx was using flaps as thrust blockers like Azimech's boost flap on his cars.  I was wondering - if we made a turbo tail rotor with 2 or 3 junos, could we use flaps or airbrakes so that the number of Junos powering the tail rotor will determine if yaw is straight, left, or right.  Anyone interested in trying this?  'Got too many projects open to start another on.

 Gonna work on that demo rotor head I posted a few pages back, see if I can get collective adjustment to work.  No promises.

 Edit: so maybe it makes more sense.

Edited May 12, 2017 by klond