quadcopters vs helis?

[sl4ppy]

Why does it seem so many FPV rigs use quadcopters instead of helis?

I'm getting started with an Easy Star to learn the ropes (900mhz), but would like to switch at some point and was curious if there was some inherent advantage to quads over helis?

[Phil H]

Pluses for the Quads are: they fly very much like a coaxial machine, they have the "do it yourself" build element that you can't achieve with a helicopter, they are a good stable aerial photography platform at a reasonable cost, the control software is open source (have a look at the diydrones.com or multiwiicopter.com sites), they can be fitted with a variety of low cost sensors (GPS, Magnetometer, Barometer, Accelerometer, Gyro etc) to link with the Aurdino board, they can take off and land on a dime, are somewhat insensitive to wind, and finally they gives a good flying platform to experiement with FPV and autopilot programming to make it behave like a drone. A well built Quad should give you a 10 min flight time.

On the minus side, they are not really for doing serious aerobatics like a collective pitch heli ( though you can see people looping them) and when a motor craps out it all falls out of the sky. A 6 or 8 motor multicopter is less sensitive to the motor failure issue. Finally the visual cues are a real bugger with a multicopter. What is forward and what is backwards, sideways. It is easy to get it wrong.

All good fun though.

Phil

[stevec]

I have been wondering about this as well, I have several helicopters, and really fancy doing some fpv flying.

I would like to know how much harder is flying a helicopter in fpv than a multi rotor?

bearing in mind I can fly my heli already. I never got on with the "wooly" feeling of the throttle on a fixed pitch machine and found them quite hard to get back down to the ground.

bearing in mind I can already fly the heli, is there any point in spending another couple of hundred extra to build and fit out a multi rotor either a tri or quad?

I am planning on doing the easystar/bixler/ easyto fly plank, first then moving the gear across to the heli once I am used to the perspective of fpv.

The only thing that I can see as a problem with a helicopter as an fpv platform is the narrow stance of the legs and locating the camera so that you get a decent view when landing. both of these are relatively easy fixes (bigger landing gear).

Maybe people filming with quads are people who don't fly helicopters as much.
Or is it down to the cost of a crash, although 4 motors and esc's bundled with a control board and the other bits are expensive, crashing will only cost a few quid as the frames and props don't cost much, unless you damage the fpv gear...

My big raptor gasser was pretty stable and would hover in 10 mile an hour winds pretty much hands off, it could carry a huge payload compared to a multi rotor and as such a litle go pro and associated equipment would only weigh a little more than the canopy and have almost no effect on performance.

Maybe it is about perception, I have noticed that the bigger the helicopter the greater the feeling of impending doom, so perhaps people won't let you film from a 90 size helicopter when they wouldn't perceive a little 500mm quad as a danger..

is there anyone on here who has flown both a heli and a quad/Tricopter who can say what the differences are from a pilots point of view?

Cheers
Steve

[sl4ppy]

My gut reaction is that in a quadcopter crash, the motors, esc, and batteries probably come out just fine, and the air frame is usually under $100 for an entirely new one, and some new props, and you're good to go...

So perhaps they are much cheaper to crash...

I've been thinking about the Scorpion Y-650 as a base. $88 for the complete air frame, and directionality is fairly clear unlike most quad copters.

[stevec]

I've been looking at the scorpion too but six speed controllers and motors has put me off that for the time being. I thought it was a traditional tricopter but the tail is fixed meaning the added expense of a controller board etc...

I was thinking of doing a tricopter with one of those super cheap flybarless controllers. I think it would need an extra gyro for tail control but it should be easy enough.

/Steve

[MattFL]

I have a trex 450 sport and I've been thinking hard about an exchange for a quad, because I am becoming really interested in fpv and AP. I've never flown a quad, but from what I've observed they appear easier to fly smoothly and much cheaper to crash. With a heli, if the main rotor touches the ground you're looking at many broken parts and hours to repair. With a quad it seems that frequently all you need is a new prop or two for a few bucks. Also a quad seems safer around people, not that this is ever a good idea to fly near people... But with a heli if something goes bad and someone does get hit then they're going to get sliced up good, with a quad maybe it won't be so bad?

[Windbreaker]

I just finished building a quad copter and have flown it a few times now that it's more or less properly tuned.

Of course there were a couple of instances where it tipped over and the props made contact with the dirt. I cut throttle before they hit.

The result was: one small nick on a prop that I dressed out and rebalanced. There was some dirt that had to be wiped off. Other than that, nothing was bent or broken.

The 15" props don't have a lot of inertia. Cut the power and they'll come to a stop fairly quickly, unlike main rotor blades that will thrash themselves to bits, along with bending a lot of parts.

And even if I did break a prop, it's $8 to replace. An equivalent helicopter with that much lift capacity would cost $80 or more in replacement rotor blades.

As for repair/replacement, there are only four moving parts: the motors.

I looked at a lot of motors and decided to get Cobra motors with matching ESCs. They're nicely built and the ESC's can handle a PWM frequency of 400 Hz. Price is good, too.

The ESC's are also easily programmed with Cobra's programming card. Select the settings on the card, connect it to the ESC, then power up the ESC (while it's connected to the motor). That's it. If you're setting up an octo copter I can't see doing it any other way.

BTW, here's the thread where I describe just about everything I did: http://helifreak.com/showthread.php?t=360302

[juz70]

the answer is this

helis are harder to set up to fly FPV

quads are easy to tune, from beginners to advanced (with the right controller eg. coptercontrol)

helis are notorious for their vibrations

quads are generally smoother (nice video)

Quads generally will have longer flight times.

Quads have more space for FPV gear, gopro, OSD

quads are tougher

quads will fit into tighter areas

quads are safer

quads are way cheaper to crash, and YOU WILL CRASH flying FPV.

quads are easier/quicker to repair, spend your time flying not re-building

3D helicopters are made for 3D flight

and YES, you can fly hard with a quad

finally, quads just make a better FPV platform.

YouTube

YouTube

[stevec]

Originally Posted by juz70

the answer is this

helis are harder to set up to fly FPV

quads are easy to tune, from beginners to advanced (with the right controller eg. coptercontrol)

helis are notorious for their vibrations

quads are generally smoother (nice video)

Quads generally will have longer flight times.

Quads have more space for FPV gear, gopro, OSD

quads are tougher

quads will fit into tighter areas

quads are safer

quads are way cheaper to crash, and YOU WILL CRASH flying FPV.

quads are easier/quicker to repair, spend your time flying not re-building

3D helicopters are made for 3D flight

and YES, you can fly hard with a quad

finally, quads just make a better FPV platform.

]

That video is sweet !! I was watching this the other day and the one going in and out of the house. fantastic stuff.

I have a few questions regarding the statements above though.

I have a trex 450 clone with an airwolf body on it, I am running a crappy old belt cp motor and I have scale like throttle curves on it so +9 degrees - 5 or so, the heli flies great and the body isn't light, so I do dispute the claim that a quad can carry more load.

Vibrations, I agree with that one and it is the big issue for me, I have watched a few FPV heli vids and most seem to have some wierd picture oscillation going on and I can only assume this is vibration induced and interfering with the frame rate so it manifests itself in a strange way.

crash costs I can't argue that one.

smaller space? yes the video going through doors is great and my 450 wouldn't fit though a door with the rotors out but helicopters are just as manoeuvrable.

3d wise OK you can loop and roll a quad but sustained inverted and it drops faster than seagull crap. I don't fancy 3d fpv anyway but the heli is more versatile as a flying machine at this point in time, there will be a day I am sure when someone makes a tri or a quad out of tail set-ups from a heli and have a central motor this will enable throttle curves to be run and inverted flight will be sustainable. Using this train of thought will also allow much larger set-ups running fuel engines.

I can't argue that they are better fpv set ups but when it comes to safety quads can and do hit hard, and I think the perception of no danger from a quad makes them more dangerous, because of the nature of an electric motor they just keep cutting you until you take power away or the prop has shattered down to the hub. both are dangerous.

I am just wondering if guys learnt how to fly FPV on a helicopter would they perceive it as any harder than other types of flight?

with the auto pilot technology being real nowadays it is entirely reasonable to assume that you could use fly by wire rather than direct control to fly the helicopter using the same tech that is residing in the multi rotor controllers. I realise this is some way off being available to joe public but it will happen and already has with arduino etc but you need to know your way around the code at the moment.

I am going to build a plank for my first foray into FPV but I am seriously considering using one of my existing helicopters as my first rotary wing platform just because I have lots of helicopters sitting here doing very little. I am even trying to figure a way of using stabilisation so I can take the goggles off prior to landing as this seems to be the hardest part of it.

I am not trying to start a row here but trying to look at is from the perspective of someone with a wife who doesn't approve of all thses flying toys so if I don't have to buy anything then all the better.

It will be a while before I get the cash together to buy my first set-up anyway so it is good to talk about it.

Cheers
Steve

[juz70]

Originally Posted by stevec

I have a trex 450 clone with an airwolf body on it, I am running a crappy old belt cp motor and I have scale like throttle curves on it so +9 degrees - 5 or so, the heli flies great and the body isn't light, so I do dispute the claim that a quad can carry more load.

Vibrations, I agree with that one and it is the big issue for me, I have watched a few FPV heli vids and most seem to have some wierd picture oscillation going on and I can only assume this is vibration induced and interfering with the frame rate so it manifests itself in a strange way.

crash costs I can't argue that one.

smaller space? yes the video going through doors is great and my 450 wouldn't fit though a door with the rotors out but helicopters are just as manoeuvrable.

3d wise OK you can loop and roll a quad but sustained inverted and it drops faster than seagull crap. I don't fancy 3d fpv anyway but the heli is more versatile as a flying machine at this point in time, there will be a day I am sure when someone makes a tri or a quad out of tail set-ups from a heli and have a central motor this will enable throttle curves to be run and inverted flight will be sustainable. Using this train of thought will also allow much larger set-ups running fuel engines.

I can't argue that they are better fpv set ups but when it comes to safety quads can and do hit hard, and I think the perception of no danger from a quad makes them more dangerous, because of the nature of an electric motor they just keep cutting you until you take power away or the prop has shattered down to the hub. both are dangerous.

I am just wondering if guys learnt how to fly FPV on a helicopter would they perceive it as any harder than other types of flight?

with the auto pilot technology being real nowadays it is entirely reasonable to assume that you could use fly by wire rather than direct control to fly the helicopter using the same tech that is residing in the multi rotor controllers. I realise this is some way off being available to joe public but it will happen and already has with arduino etc but you need to know your way around the code at the moment.

I am going to build a plank for my first foray into FPV but I am seriously considering using one of my existing helicopters as my first rotary wing platform just because I have lots of helicopters sitting here doing very little. I am even trying to figure a way of using stabilisation so I can take the goggles off prior to landing as this seems to be the hardest part of it.

I am not trying to start a row here but trying to look at is from the perspective of someone with a wife who doesn't approve of all thses flying toys so if I don't have to buy anything then all the better.

It will be a while before I get the cash together to buy my first set-up anyway so it is good to talk about it.

Cheers
Steve

Hi Steve

So you think that you could swap that scale canopy and mount a gopro, a 480 OSD camera, a 300mW Vtx and antenna, an eagletree OSD pro and logger and a 460 mah battery. IF you could find a place to install all that gear, do you think it would fly? and if it did, for how long? dispute all you like =] Maybe a 500 would be more suited to the task than a 450, then again a quad would cope, no problem.

I never said that quads were not dangerous, just SAFER than helis... read my post. I would rather an 8 inch prop do its best then take on a 325 or larger heli blade. Take your pick. again..quads ARE safer

dropping fast is what make the inverted quad manouvre so cool and fun. Watch them copy the move

collective pitch quads are old news fella. Been done. Google it.

anyhow... convince yourself the helis are better for FPV, then build one, then prove your concept by sharing some super kool heli FPV HD video

very kind regards
justin

[SiNYKAL]

Originally Posted by stevec

I have a trex 450 clone with an airwolf body on it, I am running a crappy old belt cp motor and I have scale like throttle curves on it so +9 degrees - 5 or so, the heli flies great and the body isn't light, so I do dispute the claim that a quad can carry more load.

I think the Gaui 500X (upgrade for 330X running gear, not the full kit with better motors and larger props...) lists it's max flying weight at 2200g. The actual aircraft is ~ 670g, which puts your payload at 1530g. This is a lot by anyone's standards in a unit of similar size to your 450 clone. There are guys around flying big Tri-Y's that'll take twice that again. To get that on a CCPM single-rotor you're talking a 600 or 700 class at the minimum.

Originally Posted by stevec

Vibrations, I agree with that one and it is the big issue for me, I have watched a few FPV heli vids and most seem to have some wierd picture oscillation going on and I can only assume this is vibration induced and interfering with the frame rate so it manifests itself in a strange way.

This is generally dependent on the camera setup (some cameras get electrical interference resulting in oscillation which manifests as 'waves' through the image) and mounting hardware. I did some tests with a MSH Protos 500 using a CCD camera and Crash9's vibration-damping mount and had all sorts of trouble. There are loads of people who do it successfully, but you're going to have less problems out of the box with a quad, which is generally smoother.

Originally Posted by stevec

crash costs I can't argue that one.

I've had a number of minor incidents with the 500X and the most damage I've managed to do is bust up a couple of props. A pack of 4 is ~ $16 where I am and I haven't even used them yet. On the other hand, I smashed the Protos during testing and spent nearly $800 repairing it (albeit with a bunch of upgrades, but still...)

Originally Posted by stevec

smaller space? yes the video going through doors is great and my 450 wouldn't fit though a door with the rotors out but helicopters are just as manoeuvrable.

3d wise OK you can loop and roll a quad but sustained inverted and it drops faster than seagull crap. I don't fancy 3d fpv anyway but the heli is more versatile as a flying machine at this point in time, there will be a day I am sure when someone makes a tri or a quad out of tail set-ups from a heli and have a central motor this will enable throttle curves to be run and inverted flight will be sustainable. Using this train of thought will also allow much larger set-ups running fuel engines.

If my experience is anything to go by you're not going to be flying 3D or long-range FPV for a while anyway. Concentrating on a stable and resilient setup is probably far more useful at this point than worrying about any of that.

Originally Posted by stevec

I can't argue that they are better fpv set ups but when it comes to safety quads can and do hit hard, and I think the perception of no danger from a quad makes them more dangerous, because of the nature of an electric motor they just keep cutting you until you take power away or the prop has shattered down to the hub. both are dangerous.

Agree. Both are going to f!ck you up. A quad is going to f!ck you up slightly less. Either way it's something to be avoided in general

Originally Posted by stevec

I am just wondering if guys learnt how to fly FPV on a helicopter would they perceive it as any harder than other types of flight?

with the auto pilot technology being real nowadays it is entirely reasonable to assume that you could use fly by wire rather than direct control to fly the helicopter using the same tech that is residing in the multi rotor controllers. I realise this is some way off being available to joe public but it will happen and already has with arduino etc but you need to know your way around the code at the moment.

I am going to build a plank for my first foray into FPV but I am seriously considering using one of my existing helicopters as my first rotary wing platform just because I have lots of helicopters sitting here doing very little. I am even trying to figure a way of using stabilisation so I can take the goggles off prior to landing as this seems to be the hardest part of it.

I don't fly fixed-wing aircraft but observe a general perception that they're easier to pilot. If you're a great / experienced heli or fixed-wing pilot I think the transition would be similar. If you're a novice at either I think heli would be considerably harder.

There are commercial stabilisation systems such as the HeliCommand which are quite popular with CCPM FPV pilots. That would enable you to set the aircraft in hover while you remove goggles to land. There are other stabilisation systems more specifically designed for quads such as the Ardupiloit Mega (see DIY drones for details) orthe DJI Innovations Wooking controller.

I've been taking off and landing without anything funky on the 500X but you're more likely to want something for CCPM.

Originally Posted by stevec

I am not trying to start a row here but trying to look at is from the perspective of someone with a wife who doesn't approve of all thses flying toys so if I don't have to buy anything then all the better.

It will be a while before I get the cash together to buy my first set-up anyway so it is good to talk about it.

Just expect to crash whatever you start up with. As a really basic breakdown...

CCPM Heli - Going to cost you significantly each and every time it touches the ground in an imperfect way.
Quad - Going to cost significantly less and be generally more resilient to funky landings.
Foam Fixed-Wing - You'll be able to plough this thing through fields time and time again before ever spending cash on it. When you do it'll either be $10 for glue or $80 for a whole new aircraft to transfer parts to.

Good luck! Let us know what you decide and how you get on with it all...

[MattFL]

>> and YOU WILL CRASH flying FPV.

I'm not disagreeing, but man I really didn't want to read that! I'm saving now for my first FPV setup and I'm wrestling with the decision to trade in my TREX 450 Sport for a quad before I even get started with fpv.

In regards to heli vs. quad, strictly talking about flight characteristics, is one easier to fly than the other via FPV? My heli is stabilized (HeliCommand 3D) which helps A LOT, but I'm super curious to know what I'm in for the very first time I put on the goggles and go for it.

In general what I observe is that these little helis are not designed or intended to be stable fpv platforms, so trying to stabilize them is an uphill battle. They are designed to be agile for 3D, and as a side effect they are inherently unstable. The quads seem to be intended for stability from the start which has got to be a great advantage for FPV and AP.

[stevec]

Hi Justin,

Could you please let me know how much the gear you mentioned there weighs?
I want to do some testing. I don't trust the weights that HK quote and extra cables etc always add some you didn't think of.

I happen to have a trex 500 in the shed I was also considering stretching the 450 out to run 350mm blades. running 2 2200 batteries or a big single battery slung toward the rear of the helicopter to counterbalance the camera arrangement on the front. not sure how it will fly but I cant imagine the electronics weighing much more than the airwolf fus I am running on my 450.

with a stretched boom and longer main blades running a lower headspeed the heli should be able to carry a lot.
the key will be distributing it all around to it maintains a decent CofG

I just wonder if multi rotors are so efficient at carrying loads then why don't we see them used commercially in full scale applications? gyro stabilised controls have been available to military manufacturers since just after world war 2...

I agree with the advantages you have stated and like I said I am not trying to bait an argument just reasoned debate..

I think they are as cool as, but I am trying to find out proper reasons for rejecting helicopters out of hand. after all this is Helifreak ;-)

repair costs --- we all know that helis are expensive
repair time ---- this doesn't put me off that much as I get more time to fix than I do to fly anyway.
easy to tune, so are helis once you have learnt it.
not so sure about the flight times on a relative set up, but saying that if you put a 3000mah battery on a trex250 it would stay up a while... don't know how much it could carry though.
my 45g mcpx flew ok with a 19g keychain camera on it battery life was about a minute shorter but not drastically reduced.

I have subscribed to your youtube channel by the way them vids are fantastic.

/Steve

[MattFL]

Originally Posted by SiNYKAL

......<SNIP>......
I don't fly fixed-wing aircraft but observe a general perception that they're easier to pilot. ....<SNIP>......

This is very true in my experience. I started with a cheap foam plane, and with no simulator at all after a few tries (admittedly a few bad words and some clear packing tape) I was flying. The heli took a LOT more effort to get into the air, and I'm still not good enough with the heli to fly around in circles like I did with the plane. I can flip, roll, hover nose in and sideways, etc.. but for some reason still can't get the hang of continued forward flight like you do with a plane.

[stevec]

Originally Posted by MattFL

>> [I]and YOU WILL CRASH flying FPV.

[/I
In general what I observe is that these little helis are not designed or intended to be stable fpv platforms, so trying to stabilize them is an uphill battle. They are designed to be agile for 3D, and as a side effect they are inherently unstable. The quads seem to be intended for stability from the start which has got to be a great advantage for FPV and AP.

Inherently unstable is a bit of misnomer really, by the time you have slung the extra weight on the bird the pendulum effect of it will greatly increase its reluctance to do anything other than hover. a well set up helicopter should be no harder to fly than any other well set up heli. the only difference is the amount of throws you set. there is no reason why you couldn't make a sab goblin tame enough to put training gear on it and teach a newbie to fly on it. These superheroes who fly the helicopters are as adept at setting them up as they are at flying them and that is where the key is.

if you are used to doing pirouetting flipping moves then you can be pretty sure the guy doing it isn't battling to hold the thing in a hover and fighting erratic tendencies, the pilot has tuned that airframe and set up so that he knows exactly how it will behave in all orientations.

This is what I love about helicopters, you don't actually have to keep buying helicopters as you get better you just tune it to do what you can do with it. unless of course you are flying an old Raptor 60 like me which won't give more than about 11 degrees of pitch !

The only difference between my Trex 500 and Alan Szabo Jr's is the mechanical and electrical set up he has done on it. after all the trex demo vid was supposedly done on a box stock heli...

I have exactly zero interest in doing fpv 3d I don't think my guts could take it.

And I understand I will crash but I crash in normal flight too... pushing the abilities tends to have that effect.

/Steve

[MattFL]

By inherently unstable I meant relative something like a coaxial heli. For example, if you take a coaxial out with no wind, put it in a hover, you can walk up and bump it with your hand and it will bobble then return to a hover. If I tried the same with my 450 sport (OK I would use a stick ) then it would most definitely not return to a hover and it would slide right into the ground quickly. The HeliCommand 3D is spectacular for stabilizing in my experience, but it's still not a hands-off hover if you're not using the camera on the HC. So something like a coaxial is inherently stable, it will stay put and you need to give inputs to make it move. A CCP heli requires constant inputs to keep it in one place. I've never flown a quad and I'm very curious to know which of these two the quad most closely resembles.

[stevec]

Ahh now I got ya

so the video for the HC3d isn't true then? that shows a bloke setting the tx down and walking away with the helicopter hovering away quite happily... perhaps you need to turn up the stabilisation a bit? the videos I have seen look like you should be able to take your stick and prod away with the helicopter returning to centre when you let off of the prod.


The extra weight does smooth things out though, the only thing I have experience actually flying with extra weight of is a scale body and a gasser converted helicopter. both of them are much more stable than the original helicopters. the raptor 90 gasser I had would sit there all day hands off pretty much it was really easy to fly compared to a 450. I can only imagine how good that would be as an fpv platform but I can't risk the investment on an experiment. the last crash I had with that is going to cost about £600 to fix, and I had to buy a new radio for peace of mind... another thread...

/Steve

[MattFL]

Originally Posted by stevec

Ahh now I got ya

so the video for the HC3d isn't true then? that shows a bloke setting the tx down and walking away with the helicopter hovering away quite happily... perhaps you need to turn up the stabilisation a bit? the videos I have seen look like you should be able to take your stick and prod away with the helicopter returning to centre when you let off of the prod.
.....<SNIP>.....
/Steve

It is true, in specific conditions. There are 2 aspects to the HeliCommand 3D; the artificial horizon that is an average of the heli attitude over the last several seconds (created by the gyros), and a camera on the bottom of the HC. If you have the camera enabled, then yes if its not too windy and you're under about 10' altitude then you can put it in a hover and walk away. BUT the camera only works until about 10' off the ground, and you have to be over something with texture so the camera can detect movement. If you're up 20' or have the camera disabled then it will not hover hands-off, but it is 90% easier to maintain a hover than without it, especially with gusty winds. I fly almost effortlessly in winds now that I would never even attempt without the HC, I do like it that much, but it by no means turns the heli into a hands-off machine.

Assuming you're above 10' or have the camera disabled, what the HC does is tries to keep the heli in its average attitude. For example, assume you are hovering perfectly flat for 10 seconds. Now if you whack the sticks and let go, or if a big gust of wind comes up, the HC will do a real nice job of returning the heli to the attitude it was in before the event occurred (flat). But if you tilt it 10-degrees forward to fly down the street, then after a few seconds 10-degrees forward becomes the new horizon, and if you flatten it out and then let go of the sticks, it will return to 10-degrees forward. So to get back to a hover you need to hold the stick back for a few seconds until the HC sees flat as the new horizon again. It's difficult to explain, but you adapt pretty quick, and it has saved my hide many times! But if you fly down the street and expect to let go of the sticks and have the heli stop and wait for you, that's not going to happen and it will fly into something or slide down to the ground and crash.

To stay in one location requires constant inputs because the wind is going to blow you all over. You need some kind of positional awareness. For example GPS, which is probably the best once you're above a few feet altitude. In my experience the camera method works, but with limitations.

[asanovrus]

although my experience is limited to Mix F45 and ar drone I found advantage of fixed pitch heli with a flybar in that it will never flip whatever u do. once I rased it too high so icouldn t see it, all I needed to do is slow down to get it back. vibration was only when flybar was bent after a crash. it 's cheap to repair too. I love ar drone as much but I needed to install specific program to my android tablet to make control more like rc rather then videogame. autocorrection and autopilot are very handy when connection lost or u r in stressed. there's sdk to develop your own program to control that flying linux computer.

[jolyboy]

FPV on a trex 450 is tooo fun. Invert = fun.

Heli FPV is hard trying hover. How to overcome this? Dont try to hover while FPV

IMO If you are flying based on repair times your doing it wrong. Fly something cheap/easy for when you are feeling tired and broke