wlfk

Phil, you had this right the first time.  You can get headspeed governors for either electric models or IC models. If an electric model ESC is in governor mode, it trys to modulate the throttle to maintain a headspeed set by the transmitter throttle output. This is a function provided by any decent helicopter ESC - Jazz, Align, Emax etc... How well it works is a matter of debate. Some people use it; others don't. It has nothing to do with the transmitter as the transmitter can't monitor the headspeed. Some transmitters do have some degree of compensation, increasing the throttle setting if you're using a lot of cyclic input, for example. But this is an entirely different function and does not involve any feedback from the model. For IC models you can get governors that use magnets in the main gear to determine the headspeed, and adjust the throttle to suit. In a sense, brushless motors at all-out throttle are governed anyway by the characteristics of the motor. A brushless motor has a working speed (kV rating x supply voltage) that is roughly independent of load. K

Always worth a try...

Sooner or later, might be me! Always loved the cub - a very pretty plane. K

It does look interesting - I reckon it's more helicopter than anything else though. In the same way that a chinook is a helicopter - just the concept has been taken a little further. Try googling 'tricopters' or 'quadrocopters' for some similar, albeit larger beasts. Some of them have been implemented using variable-pitch propellors rather than variable speed and are very maneuverable. K

"do not think if I by a £600 heli that it will make the road eny less bendy" I can fly my £600 heli quite well, but I couldn't fly my flatmate's Walkera #4. He bought it with the notion that as it was less complex, it would actually be easier to fly. It's a principle that works for some things, but not in this case. When I spent a fair amount of $ on a nice camera, my pictures suddenly got a lot better. A bad workman blames his tools, but a good workman will want good tools nonetheless. K

I'd make it an electric. K

Mosquito Lysander Catalina

Translational lift is a big part of it - and it's very impressive what a difference it makes. If you transition from the hover to forward flight the helicopter will climb a bit. If you try to auto the T-Rex 450 it will float down gently in a breeze, but plummet if you try one with no airspeed. The other part is that you can convert forward speed to headspeed in a flare, to give you a bit of time to position yourself for a smooth landing. K

My experience is that you do have to spend money to get something that flies well and crashes gracefully. My flatmate bought a Walkera #4, for which he paid quite a lot, and the beastie never flew. Parts were expensive too. I know there are offerings out there that are better quality, but I've yet to see something that isn't collective pitch that feels solid. It isn't about whether it will do advanced aerobatics or not. Even if you invest in an 'expensive' helicopter it seems to pay to invest in good parts. I splashed out on metal-geared servos and have yet to break one, but reading about on the forums it seems that people who go for plastic gears end up replacing gearsets every crash. It would drive me spare. I also recently invested in a metal rotorhead. When I had a plastic head I broke expensive parts all the time and it cost a bomb. I've yet to break anything in the metal rotor head, and have concluded that the plastic one was very much a false economy. If I crash my T-Rex 450 it normally breaks the tailboom (£1), main shaft (£2), and feathering spindle (£1). If I'm unlucky it will damage the tail casing (£5) or some other part such as the canopy. So an average crash might add up to £10. Crashing isn't hugely expensive, so long as you don't do it too often - which I did at the start. This is on a T-Rex 450 with a full metal rotorhead. I think I sunk £200 into learning to hover all orientations and fly circuits - then one day to my great relief I suddenly stopped crashing. Much. I would have chosen a T-Rex 450 to review on the grounds that you can get aftermarket parts on Ebay for much cheaper than the shops sell them. I pay something like 90p for a tailboom on Ebay, whereas the list price is £2.50 each. But if you go through the regular channels then big helicopters aren't actually that much more expensive than small helicopters. I sunk about £450 into my T-Rex 450 and £600 into my Logo 600. It's battery costs where you really see the difference. And then, I personally never see the appeal of something that flies out of the box. I enjoy putting the things together, finding how they work - sometimes on quite a deep level. What happens if I put on 335mm blades rather than 325s? Why did my helicopter suddenly start to plummet whilst hovering (vortex ring). Why does an autorotation work so much better if you have a bit of forward airspeed? I can accept that some people might want to pick something up and simply learn to hover and there's nothing wrong with that. But I can't see how anyone could write a magazine series about it. K

Does that £300 include batteries, Tx etc? Gyro + tail servo: £100 Cyclic servos: £60 2100mAh 3s battery: £30 T-Rex 450X: from revolution models: £100 An old model, but would still fly OK Total: £290 not including the radio and charger. Probably £40 for a PCM or 2.4 ghz Rx. I don't think I've missed anything - the T-Rex should come with blades, ESC and motor. You can build one considerably cheaper than that - perhaps £20 for cyclic servos and £50 for a cheap gyro and tail servo. But I think this would be false economy. I've never broken a 65mg servo, whereas other people seem to break cheap servos all the time. Metal parts on the small helis break or bend very rarely - the main shafts bend and the feathering spindles can end up like spaghetti. Plastic parts break much more frequently. Ebay for cheap tailbooms and other parts - often costs 2-3x less and quality is fine for us beginners.  K

http://www.halfvalue.com/wiki.jsp?topic=Royal_New_Zealand_Air_Force:  The NZPAFs first action came in 1930 when the Moth dropped an improvised bomb made out of a treacle tin on to a ship suspected of gun running. The bomb did no damage, fortuitously, as the target turned out to be a local missionary vessel. K

I don't know about ESKY products, but anything with collective-pitch should be OK in moderate breezes. A 450 size (325mm blades) can handle quite impressive winds. K

There's something about biplanes.

Sensitivity is the same as gain, which you set through the gyro channel on your TX K

Going back to the Spectrum reset issue, my theory is that it isn't so much a question of brown-outs as susceptibility to electrical noise. Or perhaps a combination of the two. On trextuning.com they did some tests that as I recall showed that the Futaba RXs would actually brown out before the Spektrums did and took longer to recover. Can't find it any more. But people have been complaining about Spektrum lockouts but not Futaba - as far as I'm aware. I'd also take issue with the idea that sensitivity to transient voltage drops isn't an issue. What you want out of a BEC is: It should give good power to the servosIt shouldn't go on fireIt shouldn't fail open circuit and fry £200 of electronicsAnd lastly of course, that it should power your receiver happily. If it appears to be meeting the first 3 criteria but not the last, then it seems to me the receiver is the weakest link in the system and it's a shame it isn't more resilient. K

It may be that some of the sets have left the factory without the correct GUID number having been programmed in, but it's also the case that if you turn the Futaba system on then off quickly you can erase the TX GUID number leading to the same problem. Well, a few months back I tried to fire up my T-Rex and found that it had de-bound to the TX. It worked after I re-bound it and I was slightly concerned. A week or two back I ordered a new receiver which worked straight out of the box... I think I have a problem. I phoned Ripmax who were frankly quite dismissive of the problem - they didn't deny that it existed but did deny that it was a significant issue. I tend to disagree. If the problem affected particular batches of TXs then it may well be that clusters of receivers are in use in particular areas, making the problem much more significant than it would be if those TXs were randomly dispersed. If TXs can lose the GUID the current state of the problem doesn't predict the future. For example, the average FAAST system has probably only been used for a few months. 4 years down the line, and when people have converted more of their models to FAAST and are using it more heavily, the proportion of affected TXs might have increased tenfold. Having said that, there are a few other problems with the TX (e.g. throttle hold reverts to idle-up pitch curves) but in general I'm very happy with it. It's been nearly bombproof - at one point I had a 2.4ghz camera mounted on my helicopter. The TX interfered with the camera so it was unusable. But the radio control continued to work fine. By all accounts this doesn't work with Spektrum! Incidentally, Spektrum might have fewer programming issues, but the forums suggeset they do have a nasty habit of locking out due to voltage glitches. K

me too. K

Ideally you should only use about 80% of a LiPo, so you should be landing before you start to see any power loss. There are two reasons for this. Firstly, you can crash because you don't have enough power to stay in the air. The drop-off can be surprisingly fast. Secondly, it's better for the batteries, and if you treat them gently they will last longer. There are now some LiPos that are less sensitive to being over-discharged. You're meant to get a timer to tell you when to land. You start off by playing it safe, then monitoring how much charge you're replacing into the cells. K

Simply not leaving the LiPo connected to the helicopter, then forgetting about it. When you're flying, you'll be drawing many times the current it takes to run the receiver and servos. The worst case scenario is one of the servos is binding and drawing a few amps. Even then, you should get an hour or two of testing before you start to damage the LiPo. If you put in the LiPo then leave it overnight you might start running into problems. K

No need to get an extra pack. Just unplug the motor connectors from the ESC so that the motor can't start up. Same advantage - if the motor aint connected it isn't going to go anywhere. Make sure the connectors can't short-circuit if they're unplugged. K

No - I only have one and haven't seen any others - it's a small one for mini-helicopters. You can get them quite cheap on Ebay. Have fun tmrw, K

I have that TX and will help with specific questions. I don't know the Century Mini Pred. Where have you got to so far? I tend to start with the swashplate settings and servo directions. I think you need 90 degree swash settings (in the manual) and you want to make sure that when you increase the collective the swashplate goes up and that cyclic mirrors the stick movements. You might need to reverse some of the servos in order to get everything moving as it should. Do you have a pitch guage? Start by setting the pitch curve at 0-25-50-75-100 and make sure that the blade pitch is '0' degrees at the 50% level. You'll then want to adjust the pitch settings so that you get about -3 to +10 degrees of collective. Unplug the motor whilst you do all this, to avoid catastrophes. Then get back to us with the difficult bits. K

I've seen a piccie somewhere of someone hovering a .90 in their living room - with their friends sitting calmly on the sofa (rather than behind it, as any sensible person would do). http://www.youtube.com/watch?v=uxni3OXT_Vo There we are. K

I'm curious that you're running 2 brushless motors from 1 ESC - it isn't meant to work, though if I understand you correctly it clearly is... K

Let us know how you get on. K