totm june 2018 Work-in-Progress [WIP] Design Thread

[Gman_builder]

@erasmusguy 

Operation SSTO Float Plane is a go

Had to redesign a "little"

 

[EpicSpaceTroll139]

I'm finally done with on-campus exams, so I took the opportunity to perform a spine transplant on my E-24 prototype. Instead of an I-beam spine, it now has one made from the large curved radiator parts, conveniently making it somewhat lighter. But more importantly:

No more I-beams = no more magical-I-beam-in-the-aft-rotor problem.

I kind of wish I could add a transmission to keep the rotors synchronized, but such a contraption would be only one more thing that could break, and would eat up internal space, for a minor aesthetic gain.

Still need to actuate the cargo ramp, and hopefully figure out a better pitch control system for flight at above 45m/s or so, as even all those reaction wheels and those strange looking wing stubs at the back aren't enough to keep the nose down at that point. It is possible to keep it down by toggling one of the blowers on the forward rotor, but that results in an annoying yaw-left tendency due to the incomplete balancing of the aft rotor's torque. Although that might be acceptable, as it allows the helicopter to go 75m/s with ease.

Edit: just realized the cargo ramp might be part of the pitch problem, because KSP errordynamics means that it produces significant downforce when the helicopter moves through the air at speed. That won't be good for the door mechanism either.

Edited May 3, 2017 by EpicSpaceTroll139

[selfish_meme]

5 hours ago, EpicSpaceTroll139 said:

Edit: just realized the cargo ramp might be part of the pitch problem, because KSP errordynamics means that it produces significant downforce when the helicopter moves through the air at speed. That won't be good for the door mechanism either.

Haven't you really just replicated a mk3 cargo fueselage anyway? Upside down cargo bays and mk3 cargo ramp would probably replicate the functionality with fewer parts. I would imagine they are a deal heavier though and maybe that does not work for you.

[EpicSpaceTroll139]

22 minutes ago, selfish_meme said:

Haven't you really just replicated a mk3 cargo fueselage anyway? Upside down cargo bays and mk3 cargo ramp would probably replicate the functionality with fewer parts. I would imagine they are a deal heavier though and maybe that does not work for you.

It's not the weight that's the problem (I've used them on plenty of Helis before, and my new design is actually slightly heavier), it's the shape. I'm trying to avoid the rounded bottom edges of mk3 bays, which make it harder to drive/fit rovers inside. With the square corners of my design, the wheelbase can be up to the full width (3.1m?) of the inside of the bay, instead of just the relatively narrow (2.4m?) flat part of the regular bays. Also, with the new spine conveniently having some lateral area, I might widen the bay a bit to about 3.6-3.7m.

Edited May 4, 2017 by EpicSpaceTroll139

[Azimech]

4 hours ago, EpicSpaceTroll139 said:

It's not the weight that's the problem (I've used them on plenty of Helis before, and my new design is actually slightly heavier), it's the shape. I'm trying to avoid the rounded bottom edges of mk3 bays, which make it harder to drive/fit rovers inside. With the square corners of my design, the wheelbase can be up to the full width (3.1m?) of the inside of the bay, instead of just the relatively narrow (2.4m?) flat part of the regular bays. Also, with the new spine conveniently having some lateral area, I might widen the bay a bit to about 3.6-3.7m.

It's the reason I don't use a ramp at all on my non-MK3 cargo helicopters and airplanes ... too much drag and unwanted lift in all but the right direction.

[EpicSpaceTroll139]

8 hours ago, Azimech said:

It's the reason I don't use a ramp at all on my non-MK3 cargo helicopters and airplanes ... too much drag and unwanted lift in all but the right direction.

Yah I've considered leaving it off. However, it seems I've gotten it to a point at which exchanging the ramp/door for a fixed ramp doesn't change the speed much (goes from about 85m/s to 87m/s), and the fixed-down ramp design seems to have a problem in which it can permanently distort the floor of the helicopter during takeoffs and landings. It's kind of bizarre, I'll have to get a screenshot.

[Azimech]

16 minutes ago, EpicSpaceTroll139 said:

Yah I've considered leaving it off. However, it seems I've gotten it to a point at which exchanging the ramp/door for a fixed ramp doesn't change the speed much (goes from about 85m/s to 87m/s), and the fixed-down ramp design seems to have a problem in which it can permanently distort the floor of the helicopter during takeoffs and landings. It's kind of bizarre, I'll have to get a screenshot.

Just raise the gear, you'll need a shorter ramp ;-)

[EpicSpaceTroll139]

22 minutes ago, Azimech said:

Just raise the gear, you'll need a shorter ramp ;-)

I should rephrase. It distorts the floor of the helicopter when any weight is put on it. So if I did that, I would just postpone the problem until I retracted the gear. Maybe I could find a design of  fixed ramp that doesn't do that, but besides, if I make the ramp shorter  than the gear, the grippy tires won't be available to keep the heli in place when doing things like this.

Note that unlike in real life I do not have cyclic available to tilt the helicopter like that without going backwards, so I would be level.

[Azimech]

16 minutes ago, EpicSpaceTroll139 said:

I should rephrase. It distorts the floor of the helicopter when any weight is put on it. So if I did that, I would just postpone the problem until I retracted the gear. Maybe I could find a design of  fixed ramp that doesn't do that, but besides, if I make the ramp shorter  than the gear, the grippy tires won't be available to keep the heli in place when doing things like this.

Note that unlike in real life I do not have cyclic available to tilt the helicopter like that without going backwards, so I would be level.

The CoM of my Titan series are in front of the rotor, I use a single Juno (AG2) on the tail pushing the tail down while hovering and I adjust the thrust limiter accordingly.

[EpicSpaceTroll139]

8 minutes ago, Azimech said:

The CoM of my Titan series are in front of the rotor, I use a single Juno (AG2) on the tail pushing the tail down while hovering and I adjust the thrust limiter accordingly.

...uh... Not exactly sure what you're getting at...

If your heli was put in a nose- up attitude (say, 5-10°) it would start to move backwards, would it not?

[Azimech]

26 minutes ago, EpicSpaceTroll139 said:

...uh... Not exactly sure what you're getting at...

If your heli was put in a nose- up attitude (say, 5-10°) it would start to move backwards, would it not?

Yep, they have a natural tendency to drop the nose and start flying forward. That's what the Juno is for, to push the tail down just enough. Reaction wheels are sometimes a little bit too limited.

More info in the manual: https://www.dropbox.com/s/5lbq08twm592iys/Titan Series Helicopters.pdf?dl=0

[EpicSpaceTroll139]

1 hour ago, Azimech said:

Yep, they have a natural tendency to drop the nose and start flying forward. That's what the Juno is for, to push the tail down just enough. Reaction wheels are sometimes a little bit too limited.

More info in the manual: https://www.dropbox.com/s/5lbq08twm592iys/Titan Series Helicopters.pdf?dl=0

I'm not sure that we're both looking at the same topic. What I'm trying to say is that, as far as I know, neither of our helicopters can hover in a purposely nose-up attitude without drifting backwards. Juno or no Juno, and regardless of the location of the center of mass, the rotor disk and thus the overall thrust vector will still be inclined slightly to the aft, resulting in the helicopter moving backwards.

With a short ramp designed for gear-up use on level ground, my helicopter would be required to hover at the edge of a mountaintop/roof/whatever in a nose-up position to take advantage of the grippy wheels to keep it in place while the player works with the payload (or Kerbals). Unless I add a second set of wheels that just barely stick out below the fuselage to act as rubber grippers... that might actually be a good idea. Anyways, with the nose-up attitude, the heli wants to roll backwards even with brakes on, which causes problems.

 

A full length ramp however can reach the ground with the wheels extended while the helicopter is level, thus allowing it to remain stationary.

Maybe I'll be able to devise some better lightweight anchoring system, but until then I think I'll want to have the gear available to help.

Anyways, I should probably get back to that secret project I mentioned soon.

Edited May 4, 2017 by EpicSpaceTroll139

[Azimech]

17 minutes ago, EpicSpaceTroll139 said:

I'm not sure that we're both looking at the same topic. What I'm trying to say is that, as far as I know, neither of our helicopters can hover in a purposely nose-up attitude without drifting backwards. Juno or no Juno, and regardless of the location of the center of mass, the rotor disk and thus the overall thrust vector will still be inclined slightly to the aft, resulting in the helicopter moving backwards.

With a short ramp designed for gear-up use on level ground, my helicopter would be required to hover at the edge of a mountaintop/roof/whatever in a nose-up position to take advantage of the grippy wheels to keep it in place while the player works with the payload (or Kerbals). Unless I add a second set of wheels that just barely stick out below the fuselage to act as rubber grippers, but that seems a bit silly. Anyways, with the nose-up attitude, the heli wants to roll backwards even with brakes on, which causes problems.

 

A full length ramp however can reach the ground with the wheels extended while the helicopter is level, thus allowing it to remain stationary.

Maybe I'll be able to devise some better lightweight anchoring system, but until then I think I'll want to have the gear available to help.

Apparently I had a too simplistic view of the situation. I figured you could maybe stick a Juno on the nose pointing up to remedy all this, maybe augmented with a boost flap for a fast variation in thrust, if needed.

But I see those Wheesley's on the back ... couldn't you use those? Maybe give them 0.5kN or something?

Edited May 4, 2017 by Azimech

[EpicSpaceTroll139]

1 minute ago, Azimech said:

Apparently I had a too simplistic view of the situation. I figured you could maybe stick a Juno on the nose pointing up to remedy all this, maybe augmented with a boost flap for a fast variation in thrust, if needed.

Maybe I could do something like that except with the Juno pointing backwards, to cancel out the portion of the rotor thrust that makes the heli want to drift backwards. Theoretically the Wheesley forward motion jets could do it too, but I'd have to tweak them down by a lot when doing this

[EVA_Reentry]

Working on a new plane. +1 to anyone who correctly IDs it!

 

 

[Thor Wotansen]

24 minutes ago, EVA_Reentry said:

Working on a new plane. +1 to anyone who correctly IDs it!

 

 

Looks like a P-39 or P-63

Edited May 4, 2017 by Thor Wotansen

[EVA_Reentry]

Just now, Thor Wotansen said:

Looks like a P-39 or P-61

Very close...

[Castille7]

2 hours ago, EVA_Reentry said:

Very close...

P-51?

[EVA_Reentry]

29 minutes ago, Castille7 said:

P-51?

Nope, cockpit's too forward. 

 

Alright, alright

It's a P-63E- @Thor Wotansenwas the closest

[Thor Wotansen]

Heh, I meant to say P-63 on my guess, but I hit the 1 by mistake, you responded faster than I could edit.

[EVA_Reentry]

I wouldn't have had I not gotten that deafening pop-up telling me I'd been quoted

49 minutes ago, Thor Wotansen said:

Heh, I meant to say P-63 on my guess, but I hit the 1 by mistake, you responded faster than I could edit.

 

[EpicSpaceTroll139]

The ramp on my E-24 retracts and deploys now.

Sometimes it will even retract again, but then it breaks.  Need to figure out a fix for that.

The payload is very close to my earlier estimate. It can lift 102 metric tons in heavy-lift mode.

It can lift about 70 in economy mode.

Its endurance fully fueled and unloaded is about 2&1/2 hours, similar to my E-50A Triton.

Also just been having fun in general.

Spoiler

Also just discovered something really cool. This thing, like a real helicopter, can land if its engines cut out, although I don't think it's truly utilizing autorotation. I suspect a significant portion of the lift comes from the wing panel belly.

Spoiler

 

Edited May 5, 2017 by EpicSpaceTroll139
Shameless plug for another craft :)

[Munbro Kerman]

Cleaned up the B-29 and reshaped the wing a bit to prepare for the X-plane thread. Something was just not quite right with the proportion of the wing so I extended a bit. I tried to use Majorjim's fairing trick, but the fuselage glitches out and explodes after passing 100 m/s, which forced me to abandon the idea. This will likely be the final product; thoughts or suggestions on anything else that should be added/changed?

I also *tried* to clean up the vertical and horizontal stabilizers. 

 

Edited May 6, 2017 by Munbro Kerman

[EpicSpaceTroll139]

13 hours ago, Munbro Kerman said:

Cleaned up the B-29 and reshaped the wing a bit to prepare for the X-plane thread. Something was just not quite right with the proportion of the wing so I extended a bit. I tried to use Majorjim's fairing trick, but the fuselage glitches out and explodes after passing 100 m/s, which forced me to abandon the idea. This will likely be the final product; thoughts or suggestions on anything else that should be added/changed?

<snip>

I also *tried* to clean up the vertical and horizontal stabilizers. 

<snip>

Tail looks like it could use a little more tapering, but other than that, fantastic!

Anyways, I finally got around to making a video of a flight (my first video ever! ) of my E-24 heli, since a couple people had asked for one. I only just now realized that it's almost 16 minutes long, so please skip through if you're getting bored (or if you don't like it ). I will try to edit it or something tomorrow. It's getting late.

I also just figured out how to get rid of my cursor. lol I'm such a newb

Note: My game is not usually this stuttery. Recording is.

Edit: May take a while to figure out how to edit.

Edited May 6, 2017 by EpicSpaceTroll139

[Frozen_Heart]

The craft themselves are unimpressive but testing if carriers are feasible in KSP or not. Might try to build a proper one if this goes well.

 

 

First attempt nailed it.