boingk

Strap your lawnmowers engine to a hanglider and ask it to run at about 100% throttle continuously with a prop instead of blades and I reckon you might get a few! - boingk

The part where it took 70% of the Hydrogen's potential just to compress it into a useable format. - boingk

Sounds like getting power to an electric motor; with weighty batteries made at great cost and with exotic materials. Ba-doom-tish. - boingk

And think of the lovely sounds, smells and experiences we'll miss out on... all to trade to a soulless electrical turbine whirr and a battery bank. I'll keep my 1940 Continental A-65 dash 8, thanks. - boingk

I got taught to call 'taxi to runup area', straight after which I would roll to the area and... wait for it... do my runup checks! This small call, although I don't think its mandatory, really made a difference to me. - boingk

Not funny quentas... as some may know I have a Continental A-65-8 powered aircraft. In other words, it requires a hand start. I once stalled it at the far end of a strip before the taxi back and it would not restart! The following radio call ensued: "Goulburn traffic, Minicab 0825 engine out on threshold runway zero-four, exiting aircraft to remove manually. Goulburn traffic." Seriously embarrassing. Next time you want a workout try pulling your aircraft down a mile-long runway! Thankfully all craft in the circuit were back on the ground by that time, though, or it might have been a bit more interesting! In all seriousness though, there are some shocking radio and other procedures out there. My favourite at Temora was the fellow giving ~30 second approach calls, with as many confused pauses and "um's" as a stoned teenager, while everyone was busy in the circuit! I ended up pipping him off the radio to make my late downwind call and thankfully I was able to land before he made another approach call. - boingk

Series hybrid electric? Really? What are the benefits over a conventionally powered craft? At this size an outrunner isn't a big deal because you have the size to use a suitable inrunner, and cooling shouldn't be an issue to start with due to proper engineering of the motor. You would NOT want to use a motor too small for the craft in either takeoff or cruise. Lithium-air aren't *yet* rechargeable. Like I said, they're in development. LiPo was originally a pipe-dream, too, but for now its what we have. Lithium Ferrous Phosphate (LiFePO4) batteries do not have the power density of LiPo. They are more stable but stability isn't an issue with proper management for LiPo cells - anything will break if you flog it. Or you could use an inflight adjustable prop. And that will weight how much? And burn what fuel? Fuel engines are at best 30% efficient, and you'll reduce that output by 10~15% by running a generator... and then that gets reduced by 10~15% by efficiency losses in the drivetrain. Assuming they got recharged! I'm not trying to tear it apart, I'm just providing a counterpoint for the ideas. I like the idea of an advanced hybrid aircraft but I don't think current technology would make it efficient at all. I *do* think a diesel aircraft would be a good option, especially if it was turbocharged. Cheers - boingk

"If we can pull this off... we're set!" I think its all a very interesting concept but we still need larger motors, higher capacity batteries and better control systems. Current battery technology is good, but it really isn't as good as we need it to be. We're utilising circa 100Wh per kilo lithium batteries... fuel gives us around 12kWh per kilo. Even if we only run an engine that is 30% efficient then we still are much better off running fuel at the moment than running batteries. Scaling it back to my good old Minicab, lets say I got my best documented fuelburn or 12L/hr getting to Temora from Goulburn. Lets say the engine was putting out around 50hp/37kW constant for the flight (75% throttle at 2200rpm). For the 90 minutes I took to fly that distance (~120Nm @ ~80kt) I would have used 18 litres of fuel and expended 155kWh of fuel energy (18L x .72 for kilos and then x 12 for kWh). That figure - 155kWh - would be equalled by a battery putting out around 43kW (85% efficient powertrain running at 37kW output), or around 65kWh for the 90 minute flight. Now if I have done my math right, at cutting-edge hobby scale of 120Wh per kilo you are looking at 520 kilos of batteries to get the same 90 minute flight in the same aircraft. Oh, and they cost $50 or more per kilo initially. Alternatively you could just use 13 kilos (18 litres) of automotive fuel. Electric flight is a pipe dream at the moment for all but the most wealthy, dedicated and ingenuitive of people. My simple (if probably flawed) example shows that fairly clearly. Most experimental aircraft being taken up for flights are relatively slick and extreme designs like the Cri-Cri, and they are being brought down again in 10 minute windows. It is a start, but to be honest that's all it is. A start. Current battery technology just isn't up to the standard we have designed aircraft around - the internal combustion engine. The next wave is most likely what is being dubbed 'Lithium-Air' batteries, and they may provide a bit of a leap forward. - boingk

For sure! I'm really thinking it'd be fun, though, to take a vintage design that is designed for a relatively heavy engine up front - like a Pietenpol - and throw a motor and batteries in it. If you budget a good amount (say 10k overall) for the battery and engine package then you'd be laughing. The big thing in shorting is looking after your battery cells and ESC. You want a good safe soft-cut on your speed control and plenty of reserve amperage on the ESC (ie 250A ESC for a max load situation of 200A). I'd say a good safe soft-cut (reduced output from batteries) would be at 3.5v/cell under load. This will give you a static reading of 3.7v/cell and should both prolong battery life and minimise the chances of ever getting a bad cell or overheat situation. Downside is you'd need more battery capacity than say a traditional RC modelling 3.0v/cell cutoff. A soft-cut is designed to get you to a landing zone after you have exhausted your safe minimum charge level (eg below 30% remaining), as opposed to a hard-cut which stops the motor entirely. Cheers - boingk

Good point, but I rekon you'd be fairly safe with minimum 90min operational duration. Worst comes to worse then call and get priority: "Volture 1234 electric ultralight request priority landing on low charge" - boingk

No idea what the reliability fears are all about - so many less moving parts and such simpler operation... I'd probably feel *safer* flying electric to be honest. - boingk

Not paid for if you are the owner/constructor and/or hold an LAME or L2 cert... that would be ridiculous. Proper checks at 25, 50, 100 etc are fine and dandy by me. If you happen to fly less than 100 hours a year then I think an annual in place of a 100 hourly isn't the worst of ideas but, again, it should be able to be carried out by the owner (if properly certified). Glad we're on the same page. - boink

Alight, let me try a different track... just in case I'm being misunderstood: Do you think it a necessary inclusion in the ops manual to have a mandated 100 hourly / 12 monthly maintenance check? As distinct from the yearly 'rego check'? - boingk

What??? I'm *for* annual inspections. Am I seriously one of perhaps 3 people on here who think annual inspections are a good idea? Gee whiz... - boingk

Also a big fan of electric flight, I have a few (read: need to get rid of some!) RC electric aircraft and find the battery technology amazing... I left off RC in highschool over 10 years ago so the progress has been a bit to catch up with, that's for sure. This is the beasty you'd be looking at for PPG, or in pairs for very light aircraft: http://www.hobbyking.com/hobbyking/store/__25413__Turnigy_RotoMax_150cc_Size_Brushless_Outrunner_Motor.html 9.8kW of power at max load and runs on 14-cell lithium-polymer batteries. Pair it with this speed control and a bunch of these batteries (about 20 of them in series for 10 x 14-cell equivalent for 30min flight time at 100A output) and you'd be set. All for about 30kg or so of weight and about $3,000. Nice! As far as I'm concerned lithium polymer batteries are brilliant, just treat them with respect and don't try and push their limits - they *will* degrade if you do that and *could* short and catch fire. If you treat their 'max discharge' limit as the absolute redline (instead of the 'burst' rating) then you should be fine. Cheers - boingk

We do not fly cars. Cars are also engineered with a lot more safety margin than aeroplanes. Again, we do not fly cars. - boingk

Andy, we're not saying we need *more* checks and balances, we're (meaning alf and myself) just saying that we think our annual check is adequate and should not be stripped. Regardless of the almost nigh certainty that it would not be stripped, I think it wise to keep it. We are not looking here at negating any particular problems, just keeping the fleet in a good and sound condition with an annual check. Its a simple but thorough affair that can be done by the majority with their L2, as I'm sure you are well aware. Checks include (for the uninitiated) things like spar condition, condition of any repairs, condition of BRS if any, condition and lockwiring of exposed nuts, etc. Things you may not see at any other time, in other words. I really still can't believe that people think there is no need for a mandated annual check - how many of you have had the mechanic give you your rego inspection slip for your car and say something like 'Shes all good to go, just had to replace a rear blinker bulb and grease your front wheel bearings, though,' hey? Finding small things through mandated checks before they cause an incident is what this kind of legislation is all about. Again, I'm not trying to say that what we have isn't enough... I just think it would be unwise to dispense with a relatively basic and necessary procedure. - boingk

Not that I know of, but then again it does seem to be a fairly well known aircraft. I had a lot of people at Natfly compliment me on it and say that they'd either seen or flown it previously. Cheers - boingk

F***ing bingo. Well said, sir.

You really think people would do an annual if it wasn't required? I'm well aware that most crashes are CFIT... and its these very people who don't follow flight procedure - leading to CFIT - that you want to trust with doing a non-mandatory annual? Doesnt seem right to me. - boingk

Unfortunately I think people just don't want annual condition reports and an expense. I think we do need the annuals, if for nothing more than to help prevent people falling out of the sky in unsafe craft.

Guys, we're paying a pittance and being allowed to have the skies under 10,000ft more or less on a whim. I, for one, will not be protesting a $100 certificate fee and $100 aircraft registration per year, especially when I currently pay around $700 yearly to register and greenslip my 30 year old Chrysler Valiant that I drive perhaps 5,000km annually. Get a grip - boingk

Might want to check out the Volksplane VP-1 from evansair.com - they are designed to use only very basic materials and to be constructed with a bare minimum of time and skill, yet still be good aircraft. Good, in this case, meaning you can fly them and they are stressed to utility category G-ratings. They are not fast, they are not you-beaut technological wonders... but they do fly and apparently quite nicely at that. They are comparable to a MiniMax 1100. Cheers - boingk

The CASA rep detailed it for me, and actually said that yes, it was not necessary to take the maint log in the aircraft. He said that for his Jab 170 he does the following: Buy a small book Rule up a few columns Write headings: Date, Hours Logged, Oil Added, Fuel Added, Operator Fill in before all flights Keep in aircraft Sounded pretty simple to me and was what I did in GA. I did not know it was a requirement but have now bought and ruled up a book as per his advice. Cheers - boingk

God no and no worries, respectively! I'm actually really interested in this engine now... sure seems more logical than a souped-up Briggs or a re-engineered VW to my mind anyway. - boingk