The HELO challenge

[Fengist]

Got a k-mail from Jeb, said he found the perfect mood music for this topic on youtube:

Enjoy!

Not bad, but entirely too badass for Kerbals. I'm more partial to this one

[Northstar1989]

Not bad, but entirely too badass for Kerbals. I'm more partial to this one

Haha, quite humorous- was this a movie you ever watched?

[Fengist]

Haha, quite humorous- was this a movie you ever watched?

Many times. Some cool pre WWI aircraft and it's campy funny. Even has Benny Hill in it as a fire chief.

[ihtoit]

yeah it's like I said, a "helicopter" is an aircraft that relies on rotating airfoils for lift and some forward thrust, with *tiny* control surfaces that are there for one thing and one thing only: controlling the direction and orientation of the nose. You might have noticed that the Bell Jetranger has those two winglets on the back, in front of the tail rotor? They're there to control pitch and yaw, they offer no lifting capabilities on top of that. A famous TV example of a helicopter is Airwolf, described in the show as a supersonic lifting body with rotors. Now, there are two things wrong with the premise of a supersonic helicopter: the rotors can't handle the stress of supersonic flight (no material yet tried, not even carbon nanotube fibre, can handle supersonic rotation on top of an aircraft; even SCRAMjets have to slow the air down so the engine can breathe), and the Bell 222 (the airframe Airwolf was built on) is about as aerodynamic as a brick, so apart from the fairly impressive looking shape could not be described as a lifting body at any speed. Not to mention the fact that the pontoons on the actual aircraft had to be painted to make it look like it had inboard weapons and inline jets* because the props made for it in "deployed" mode failed FAA inspections (the missile pod had a habit of falling off mid-flight), the closeups of the deployed pods had to be shot using a scale model.

*I've seen gas turbines that'd probably have fit in the "jet intakes" on Airwolf but I doubt they would have been able to deliver the thrust to weight ratio required to take a five thousand pound helicopter to the end of the runway before running out of fuel, never mind beyond the sound barrier at 70,000 feet!

Now, there's an idea for a sub-challenge: build a utility helicopter using the specific helicopter powerplants supplied in FS, to carry no less than two Kerbals to the island and back (so round trip range of ~65km?) while keeping the weight as low as possible. Usual no futzing with ALT+F12 to cheat your way through with a pair of command chairs strapped to a girder... etc. Remember the Bell 222 carries eight and weighs 8,000lb (3 tons) fully loaded.

I've done the utility helicopter: 13 parts, LESS than 3.3 tons on the runway(!), carries 2!

Presenting: the Kerbal Dynamics MiniRanger. Range: 240km, top speed: classified, control mechanism: ASAS/Fenestron/MechJeb. My entry for the Precision, JetRanger in reverse (after flying out twice to rescue two pilots from the Island after a previous crash, without refueling, and the subcat: Lite

With the double-gyro + fenestron control equipped with this helicopter, control is surgical and immediate. No mad flipping out, there's only one tank and the rotor head is right on top of it so no CoM movement whatsoever!

An upgraded rotor, like so:

...and (sorry it's dark, it really is the same aircraft, though!), does this count for the Boulet Award? (13,597.1m vertical ascent)

And my first attempt at a supersonic lifting body: the "KSI Airwolf". Top speed was only 220someodd at a hover ceiling of 993m (oh, I just LOVE MechJeb and the Hover toggle on the helicopter setup, makes everything SO DAMN EASY!), ran out of fuel(!), I wanted to go higher but I know that single underslung intake was going to be a problem... the winglets are just there for a bit of extra stability while the jets are firing, the thing just wanted to flip loops without them.

It did make a good distance though, it was well past the Island by the time the fuel ran out.

EDIT: Are we setting vertical ascent records? I discovered this thing called CARGO THROTTLE! The MiniRanger Bear again:

15613.9m rotor-only vertical ascent, managed a cruise ceiling of 11459m (zero bubble, vector on the horizon) and landed on its side just shy of the Island runway (hard to land in the dark with only those poxy little lights...)

...there's a thought (I keep having these, apologies): I'm gonna plant some microwave powered marker lights on the landing strips SO I CAN SEE THE THINGS IN THE DARK!

Edited February 21, 2014 by ihtoit

[Maikie_G]

I figured it might be fun to take a crack at this so I present the Teslacopter Mk. 1:

Yes, that is a mechjeb module on the back there. When I was testing it I suffered significant drifting to the left, which made the thing unflyable by hand. I thought the drift was a side effect of intermeshing rotors. Turned out symmetry had mucked up my hovermode action groups on the left rotor.

It's powered by the 0.625m fission reactor from KSP Interstellar, and features a KAS winch with electro-magnet for cargo lifting. It has a maximum crew capacity of four.

If the reactor from Interstellar is considered cheaty I'll have to figure out some other way to power this beastie.

EDIT: Couldn't resist.

EDIT2: Only just now realized this was a massive bump. Apologies.

Edited March 23, 2014 by Maikie_G

[Fengist]

I figured it might be fun to take a crack at this so I present the Teslacopter Mk. 1:

http://i.gyazo.com/63ff9d4a5e6b22a4dfeb30fe0886d544.png

Yes, that is a mechjeb module on the back there. When I was testing it I suffered significant drifting to the left, which made the thing unflyable by hand. I thought the drift was a side effect of intermeshing rotors. Turned out symmetry had mucked up my hovermode action groups on the left rotor.

It's powered by the 0.625m fission reactor from KSP Interstellar, and features a KAS winch with electro-magnet for cargo lifting. It has a maximum crew capacity of four.

If the reactor from Interstellar is considered cheaty I'll have to figure out some other way to power this beastie.

EDIT: Couldn't resist.

http://i.gyazo.com/9111c66125bd21dcba24d4c2d45801a0.png

EDIT2: Only just now realized this was a massive bump. Apologies.

No need to apologize, I'm still around and the challenge is still open.

My opinion these days, after seeing what it takes to get elec. helos flying, those reactors are fine. Even built an elec helo myself using 2 of them.

Good luck lifting with that winch. Didn't have much success myself.

Let me know how the challenges go and will be glad to add you to the roster.

[sal_vager]

Hardly a massive bump, and it's good to see this challenge still drawing entrants

[Maikie_G]

No need to apologize, I'm still around and the challenge is still open.

My opinion these days, after seeing what it takes to get elec. helos flying, those reactors are fine. Even built an elec helo myself using 2 of them.

Good luck lifting with that winch. Didn't have much success myself.

Let me know how the challenges go and will be glad to add you to the roster.

I think the major problem with the winch and especially the magnet is their massive powerdraw. Luckily power is not one of my problems.

The varying degree of control authority the thing has between flights is. For some reason it sometimes flies fantastically, and sometimes it doesn't. As for the challenge, I've already got precision award, as can be seen in the second screenshot. Working on the Jet Ranger distinction now.

[Fengist]

I think the major problem with the winch and especially the magnet is their massive powerdraw. Luckily power is not one of my problems.

The varying degree of control authority the thing has between flights is. For some reason it sometimes flies fantastically, and sometimes it doesn't. As for the challenge, I've already got precision award, as can be seen in the second screenshot. Working on the Jet Ranger distinction now.

Never had power problems, pendulum problems. Would swing all over the place. Which is why I used a radial decoupler for the 40 ton cargo. I'm on my galaxy note atm. As soon as I can get time to get out the laptop (cut & paste sucks on android) I'll add you to the leaderboard.

[Maikie_G]

Pendulum problems sound challenging. Although I reckon they might be fixed by retracting the cable to the locked position. Doesn't look nearly as cool, though... But I'll cross that bridge when I come to it. For now, enjoy the screenshots:

Coming in for a landing at the Island Runway

Landed.

Offloaded the two dumbest kerbals I could find at the Astronaut Complex

"So long, suckers!"

[plausse]

Very impressive all.. I will try.. after I find out which mod the amazing wheels are from in the OP... They look like B9.. but.. not?

[Fengist]

Very impressive all.. I will try.. after I find out which mod the amazing wheels are from in the OP... They look like B9.. but.. not?

Multi wheels mod. Sorry I can't link to it but it's on the spaceport. I can never get b9 wheels to go straight. Never have issues with multiwheels.

The tail wheel is b9. I needed a bit of extra height to make it level. It's only there to keep me from slamming the ass into the ground.

Edited March 24, 2014 by Fengist

[plausse]

Multi wheels mod. Sorry I can't link to it but it's on the spaceport. I can never get b9 wheels to go straight. Never have issues with multiwheels.

The tail wheel is b9. I needed a bit of extra height to make it level. It's only there to keep me from slamming the ass into the ground.

Ohh.. thought that mod was majorly and outdated and broken and old and... downloading it now. Cheers

[Raven.]

Ohh.. thought that mod was majorly and outdated and broken and old and... downloading it now. Cheers

check this out: http://forum.kerbalspaceprogram.com/threads/66020-B9-0-23-fixes

[Northstar1989]

check this out: http://forum.kerbalspaceprogram.com/threads/66020-B9-0-23-fixes

Installed them- they don't seem to work for me. The SABRE Engines *still* don't work for me, and though I haven't tried it, I can assume the wheels still don't work right yet either...

Anyways, Fengist, look out for a new post from me soon. First, I'm going to try strapping TTJ's onto the Helo: B like you said I could, and if that doesn't work, I might create a new design entirely...

Regards,

Northstar

Edited April 15, 2014 by Northstar1989

[Fengist]

Installed them- they don't seem to work for me. The SABRE Engines *still* don't work for me, and though I haven't tried it, I can assume the wheels still don't work right yet either...

Anyways, Fengist, look out for a new post from me soon. First, I'm going to try strapping TTJ's onto the Helo: B like you said I could, and if that doesn't work, I might create a new design entirely...

Regards,

Northstar

Actually the wheels with b9 do work. The only part that didn't were the sabres which for some odd reason started working. If you mean the multi wheels they always worked perfectly.

Unfortunately I haven't has time in over a month to kill kerbal so my attempts are on hold.

Edited April 15, 2014 by Fengist

[Northstar1989]

Actually the wheels with b9 do work. The only part that didn't were the sabres which for some odd reason started working. If you mean the multi wheels they always worked perfectly.

Unfortunately I haven't has time in over a month to kill kerbal so my attempts are on hold.

Hmmm, well I hope you have time to risk a few Kerbals' lives again soon (though hopefully not killing them- except to bugs, reverted 'dummy-launches', and my recent termination of a number of still-viable missions, I have only lost 2 Kerbals so far in my save- both due to an unexpected structural failure in one of a pair of planes strapped to a rocket- the mission being continued as the other plane made it to orbit unscathed...)

Anyways, I present the "HELO: Model C". Here she is completing the Precision Lander Challenge:

I learned a lot from the HELO: B. Particularly, that I didn't need quite as massive a chopper to airlift 40 tons stably, as long as I enclosed the cargo in the fuselage (where it couldn't pendulum very far). Thus, I was inspired to improve the design- by reducing the weight of the outboard fuselages (now attached by flat structural panels from one of my many mods), and thus being free to use fewer helicopter rotors and STILL have extra mass to budget for some small wings and a pair of Thermal Turbojets, and yet have a HIGHER rotor-only TWR than before...

The Thermal Turbojets aren't nearly as powerful as they look, by the way. Each provides only about 12-18 kN thrust in the relevant range of altitudes and airspeeds for a helicopter, and that's with the most powerful 1.25 meter pre-fusion reactors available: KSP-Interstellar's Solid Bed, Uranium Nitride-based 1.25 meter fission reactors.

And that's at quite a high mass pricetag for the TTJ's- I'm not sure that an all electric copter can make 400.87 m/s without much larger wings and at least a second pair of TTJ's... (once more, the real-world helicopter speed record, by John Trevor Egginton in 1986: 400.87 km/h (111.35 m/s)) So, it probably can't make that award unless you allow it in on the real-world speed, like you did the HELO: B.

It *CAN* circumnavigate at over 136.7 m/s, however...

Regards,

Northstar

EDIT: Actually, it looks like a lot more than a second pair of TTJ's would have been necessary to clear 400 m/s. Try at least 10 pairs for a craft that size...

Edited April 17, 2014 by Northstar1989

[Northstar1989]

Testing reveals that the wings only serve to slow the HELO down (I thought they might generate enough lift that the helicopter would fly faster with its nose tilted a bit above the horizon, but I was wrong), and in the relevant altitude and velocity ranges, electric propellers provide more thrust for less weight than Thermal Turbojets...

Thus, my next version of the HELO: C will lack the wings and TTJ's, have only one reactor (no need for two reactors without the TTJ's), and have 6-7 electric propellers mounted instead... It will be the same basic airframe, and only easier to land without the wings, so perhaps it can still be given credit for the Precision Lander challenge without needing to repeat that one again in its slightly altered form?

Regards,

Northstar

[Northstar1989]

And, the final design of the HELO: C completing both the altitude challenges

Javascript is disabled. View full album

It should be capable of all the other achievements, but I feel the need to repeat myself: 400 m/s is neither accurate (the real-world speed record was 400 km/h- less than 120 m/s) nor reasonable to ask for with a fixed-rotor electric helicraft capable of lifting 40 tons without some serious part-clipping exploits or Thermal Turbojets powered by at least fusion reactors or above... (testing reveals fission TTJ's simply don't have a high enough TWR- even if I strapped something like 20 of them onto a helicopter)

This is due, again, to the velocity curve of electric helicopter rotors- they only produce 30% thrust at an airspeed of 300 m/s, and less at 400 m/s. One would have to exceed a stationary sea-level TWR of more than 9 (extremely difficult- the HELO: C can't even do that with its forward rotors active) as drag will slow the craft down, and be capable of rotating the net thrust to a more than 75 degree angle through either pitching the craft (extremely difficult at such extreme angles with a craft heavy enough to lift 40 tons, without reaction wheel spam) or rotating the rotors... Of course, while rotating the rotors would allow this, without stacking rotors something like 6 high, it's not possible to rotate this much thrust vectoring that way without serious part-clipping on a craft that can lift 40 tons...

The forward electric propellers are actually WORSE for high speeds than the electric copter rotors, so spamming forward rotors doesn't work either- they only produce 20% thrust at a velocity of 425 m/s...

The real-world speed record of less than 120 m/s was not only achieved with an extremely small helicraft capable of safely pitching forward at extreme angles (it could have NEVER lifted 40 tons- its rotor simply wasn't powerful enough), it was also achieved at BELOW sea level, over an area of salt flats (nowhere on Kerbin does similar terrain exist)

BOTTOM LINE: The golden rule of challenges is that you should be able to demonstrate something is possible yourself before asking anyone else to do it. Therefore, Fengist, I challenge *YOU* to develop an electric helicopter that can both lift 40 tons and exceed 400 m/s landspeed in its various versions, without part-clipping, fusion or antimatter reactors. Otherwise, electric helicopters should be allowed to earn the award by beating the real-world speed record- which is still challenging; or utilize fuel-burning jet engines for forward thrust (for that challenge ONLY).

Regards,

Northstar

P.S. With the extreme TWR, intense optimization, and quadruple reaction wheels (to allow steeper pitching) the HELO: C has, its top landspeed is still only just over 200 m/s, at maximum stable pitch (approx. 50 degrees) and using "Cargo Throttle" on all rotors/propellers.

Edited April 28, 2014 by Northstar1989

[nli2work]

My attempt at landing on the VAB... apologize in advance it's not using Spitfire Mod. I don't know if I have enough ram to add another Mod to my game

[Fengist]

My attempt at landing on the VAB... apologize in advance it's not using Spitfire Mod. I don't know if I have enough ram to add another Mod to my game

Now that's... a strage helo. Well done.

[Fengist]

Testing reveals that the wings only serve to slow the HELO down (I thought they might generate enough lift that the helicopter would fly faster with its nose tilted a bit above the horizon, but I was wrong), and in the relevant altitude and velocity ranges, electric propellers provide more thrust for less weight than Thermal Turbojets...

Thus, my next version of the HELO: C will lack the wings and TTJ's, have only one reactor (no need for two reactors without the TTJ's), and have 6-7 electric propellers mounted instead... It will be the same basic airframe, and only easier to land without the wings, so perhaps it can still be given credit for the Precision Lander challenge without needing to repeat that one again in its slightly altered form?

Regards,

Northstar

And if you read this North, exactly what awards did you qualify for? No offence but there's like 20 posts and I get lost.

[Tidus Klein]

Well time to break out the old drawing board....

JEB! GRAB THE DUCT TAPE!....WHERE DOING THIS HELO STYLE!

[Northstar1989]

And if you read this North, exactly what awards did you qualify for? No offence but there's like 20 posts and I get lost.

It's been a long time, and in fact I'm about to release the HELO Model: D, with a new technology- Microwave Beamed Power!

And if you don't like it, tough- setting up 18 Gigawatts of fission reactors on the ground and beaming that power to the helicopter to run Thermal Turbojets at super-high thrust levels is the ONLY way to break 400 m/s without fuel-burning engines or fusion reactors in a helicopter (unless I gave it enough wing area that it could fly on fission TTJ power and lift alone- in which case it's a plane, not a helicopter). And even then, due to huge transmission losses beaming that power through the atmosphere, it's only possible in the immediate vicinity of the KSC...

Anyways, the HELO: C got the Church, Boulet, and Precision Lander awards before I gave up on it after seeing the speed record was still impossible with reactor-powered TTJ's...

Regards,

Northstar

[Fengist]

It's been a long time, and in fact I'm about to release the HELO Model: D, with a new technology- Microwave Beamed Power!

And if you don't like it, tough- setting up 18 Gigawatts of fission reactors on the ground and beaming that power to the helicopter to run Thermal Turbojets at super-high thrust levels is the ONLY way to break 400 m/s without fuel-burning engines or fusion reactors in a helicopter (unless I gave it enough wing area that it could fly on fission TTJ power and lift alone- in which case it's a plane, not a helicopter). And even then, due to huge transmission losses beaming that power through the atmosphere, it's only possible in the immediate vicinity of the KSC...

Anyways, the HELO: C got the Church, Boulet, and Precision Lander awards before I gave up on it after seeing the speed record was still impossible with reactor-powered TTJ's...

Regards,

Northstar

Thinking outside the box. Nothing wrong with that.