Vision325

You will have to excuse my memory of Flight Designs explanation of their hybrid concept engine but the figures they put forward required to charge the batteries was something like %5 extra in cruise. This engine has been built and was on display so their figures weren't only theoretical so it may be interesting. Their reasoning was that they would save some weight by the fact that they would require a smaller hp engine with the extra hp coming from the electric motor at peak power settings. The weight gain was quite reasonable as there was no need for large batteries due to the short duration of the electric assistance. I hope this makes things clearer. Their explanation made a lot more sense when I was their. My brain got fried with 7 days 12 hours a day racing from one exhibit/forum to the next. Before Oshkosh I was skeptical about hybrids but I have a bit better understanding of how they could fill a gap while battery technology improves. Time will tell.

Powered Electric Flight I agree about the sapphire being an excellent candidate to try out electric flight with. Any body got one they would like to donate to experiment with. Another avenue that is fast advancing to larger and larger electric flight HobbyKing Online R/C Hobby Store : Turnigy CA120-70 Brushless Outrunner (100cc eq) It is only a matter of time before these guys start to think of the manned flight market. In regards to fuel cells they suffer from inefficiency problems at the moment but they look promising. I believe there are fuel cell being developed that can use petroleum based fuels also. At Oshkosh Flight Designs had an interesting concept where they had from memory a Rotax 4 stroke with a electric motor mounted on top of it coupled by a belt drive. During take off the electric motor and the rotax worked together to increase power. Then in cruise the Rotax charged the small battery using the electric motor as a generator. This seemed to be a good stepping stone to full electric flight. Flight Design - Light Sport Aircraft Steve

Powered Electric Flight The web sites that are around are very limited in detail. This is a link to the main speakers The Future of Electric Flight - Symposium Even Yuneec who are one of the most advanced hard ware makers said they wouldn't be releasing their motors until next year. Any way its really all about the battery densities . I think at the moment that the available LiPo batteries supply 0.25kw/hr per kg and they realistically need to be 2.35kw/hr per kg to match existing Ga internal combustion engines. Chet Fuller – President, GE Aviation Commercial Systems stated GE had developed a motor with integrated motor control that is 97% efficient. This means that batteries only have to contain approx half the usable energy to be equivalent to petroleum based fuels as internal combustion engines lose approx 50% of their efficiency due to heat loses etc . Other problems are how to get the energy into the batteries in reasonable time say 30 mins. Also developing batteries that don't lose their ability to hold a full charge. I think from memory after 400 hrs flight time you need to replace LiPo batteries as they would only hold 70% of their original capacity. I had the feeling all these speakers would love to have said more but were trying to get the jump on the technology so were all holding back. With the amount of money poring into Battery technology it is just a matter of time before they become very common. I cant wait! Stephen

Hi De Duk I was lucky enough to go to Oshkosh this year and was specifically interested in electric flight. I attended the electric flight symposium there. It was a great listening to a lot of big hitters explaining their views and where their company's were at in regards to producing the technology and hardware required for realistic electric flight. If there was a consensus amongst the speakers it was that electric flight from the smallest aircraft to large passenger planes was inevitable. They all agreed that the didn't see any plateauing of battery technology in the foreseeable future and that the problems of battery weight etc will be over come. They felt that it was about five years until the first commercially acceptable two seat two hour flight trainer with a half hour charge time would be commercially available. Burt Rutan is working on electric projects but wouldn't be drawn on specifics. I learnt a lot at Oshkosh this year and the future looks very bright for electric aircraft. Stephen

Thanks for the info Guys. No I haven't been before so I will take your advice. I am really getting excited now I have booked my tickets. I will be borrowing my daughters SLR camera to take as many photos as I can. I really feel electric aircraft have a bright future in recreational aviation. Must admit with my back ground as an Instrument Technician I feel more comfortable working with electrics. Hope to catch up with any fellow forum members while I'm there. Steve

I have decided go to Oshkosh this year and was wondering if there is some where the other Aussies meet up? I am going to camp there and am really interested in seeing the electric powered aircraft that will be on display. Steve

Brilliant:laugh:

Sierra building Great work Toby, Thanks for posting updates. Its good to see you making such fast progress. This is the aircraft I hope to build in the future. I have looked at the DVDs from Gary and am impressed with the simple and practical solutions he uses in his kit making philosophy. I have looked over every bit of info and photo I can find on the net and your blog, keep up the good work. Gary dosn't update his web page much so the interested potential builders rely on guys like you and Slarti for the latest info.(Thanks again:clap:) One question I have about the fuselage frame material. The Cheetah that Slati built looked to be made from round tubing but your sierra is square tube. Do you know the reason for this and what material the tube is? Also do you know of any builders in SE Qld, Im on the Sunshine Coast. I am keen to get a look at a Cheetah/Sierra first hand. Happy building Steve

electric motors These guys seem to be developing motors with some grunt. Enstroj - Electric Apis EA1 - OUR PRODUCTS - Electric Motors - electric propulsion systems for air-planes MAY 2009 - A new ultra high powered - 60 kW, low RPM - up to 2800 RPM, high torque, low weight -12kg, Air or Liquid cooling electric motor is comming. At the same time we are preparing all things for serial production of 30 kW(40kWp)/1900 RPM electric motors, controllers with chargers included . Much lower price (as individual production) for them will be knowm in near future.

4 Seat Cougar Gary Morgan is developing a 4 seat kit dont know much about it though. Its called the Cougar http://homepages.ihug.com.au/~gkmorgan/ Steve

Hi Tony, I was confronted by the same problem of what to do after I got my rec licence:confused:. I ended up doing 8 hours training and then stopped because I felt wanted my own aircraft to fly afterwards to keep my newly gained skills. I didnt have the money to buy a Jab or simular up front so I decided to build my own aircraft and spred the costs out over a longer period of time. I feel it will add to the over all flying experience if you are able to build and then fly where ever you want. I am keen on building a Cheetah or Sierra from Morgan Aero Works. I am in Buderim so if you are interested in more info PM me. We seem to be surrounded by flying schools on the Sunshine Coast. I am certainly looking forward to completing my training. Steve

Hi Jim, Good to here of your RV12 wing kit purchase. I noticed a post from a expat aussie living in the US who imports cars to Australia from the US. It was on the Vans airforce site. He has requested anybody who is importing kits from the US and requires help with shipping to contact him as he has regular container shipments to Australia. Delivery time for the wings - Page 2 - VAF Forums Hope this helps Steve