Endurance World Record for an electric helicopter
Concept
The goal is to reach the maximum flight time with a Stock ECO with simple modifications that could be duplicated by anyone with normal tools, minimal knowledge and not huge amount of money. Erez, the engineer that calculated all data, told us that we will need longer blades and that the helicopter weight should be 700gr. or less without batteries. And the rotor speed should be around 1000rpm to get the most efficiency out of it. |
Technical information:
The Helicopter is a stock ECO 8 as it comes out of the box with some chassis parts cut off and some holes drilled here and there to reduce weight. The unique upgrade installed is the one way bearing that is very necessary for this helicopter to fly. We do not understand why Ikarus does not include that item in the kit??? The Blades are ECO16 wood stock blades that are longer than ECO8 ones. With them, the ECO16 tail boom and belt are necessary. The Servos used are normal Hitec micros, a micro RX, a HH gyro, and a Brushless ESC and a UBEC, all very normal equipment nothing very fancy. The Motor was a bit more complicated, because a light motor is needed, powerful enough for the full weight and very efficient on the rpm that it is going to work. At the same time reasonably priced, Bones tested different motors and the chosen one was MEGA 22-10-6 one of the most known brands in the market. To keep it cool a circular hole was made in the top of the canopy. The weight of the Helicopter without batteries is +- 820gr. 120gr. over what it should be forgetting 2 hours flight. But there was not much more that we could save without getting into new designs and fancy/expensive materials so it stayed like that. Knowing that flying for 2 hours was going to be less likely but to set up a new record was going to be easy. The battery, as you can imagine, is a Lipoly pack and in this case the larger the capacity the better. The larger the cell the less soldering and problems associated with unbalanced cells. However size became a problem. It had to be something new but in the end it has to be available on the market. Finally, the ideal batteries appeared. A 5,500mAh cells, 3.7V, 105gr that fit perfectly in size and weight. A discharge rate of 6C was the manufacturer claim. However in our tests we were only getting 3C due to problems with the terminal tabs. We redesigned the tabs and the manufacturer made a new bunch of them that were able to reach 6C. The pack was in a 3S4P configuration of those cells resulting a 21,500mAh, 11,1V, 1200gr. It was soldered together by Paul Goelz!!! These cells will be available soon at www.Rcmaterial.com
|
Firsts Attempts
The last world record was achieved by Mark Hopkins and it was 1h: 10m: 50s you can find more information here: http://www.fenella.net/records/ That record was broken by Hansen unofficially on December 17th, 2003 (100 year anniversary of the Wright Brothers' first flight) starting the flight at 7:45AM he reached 1h:41m, you can find more previous attempts here: Flight record That flight was done alone so I think it has a great merit. You can see a picture here of one of those attempts and the timer on the TX:
|
"Official" record
I wrote official in brackets because we have not registered the attempt with the Guinness book of world records or the FAI or any other organizations. Anyone willing to fly for a long period of time will be able to duplicate our effort with similar equipment. We are sure that he/she will achieve and probably overtake us |
Flight data
• May 27 th 2004 , Gallatin , TN , US
• 6:00AM Battery charged. Bones, Neva , Radd and GonZo went down to the flying field. We were going so early because they served breakfast at 9:00 AM and we do not want to miss it. Also because we want to fly when the wind was low. We discover later that is not true. • 6:20AM Helicopter took off after quick pre-flight check. Wind gusting but not very strong. • 6:30AM It started to rain. More people arrived, Q, Stallion, Dmonica, Pgoelz, Crb, Tony, Tdearth, Buzz, Jenny, etc. Sorry if I forgot someone. • 6:40AM Strong gusty wind started with speed over 11m/h ground level… We were considering aborting the attempt, but the pilot said "we are flying!" In our calculations afterwards we found that we lost around 15% to 20% efficiency due to the wind and rain. • 7:30AM Wind and rain stopped, thank goodness. • 7:40AM A Blackhawk flew over the flying field. • 7:58AM The battery dumped and the helicopter dropped like a rock almost in resulting autorotation and it landed a bit hard but in one piece, uffff…!!! New record 1h: 37 m! From our calculations with a nice day without rain and wind we will be able to get almost 2 hours. It was not possible to try again that same day because of bad weather, on the same day we had a tornado warning. Next day I was returning to Spain We are now looking for new challenges because the theory and technology for this one is done and proven. We know that if we want, we can surpass the 2 hour mark with a lighter chassis which has been made. It is no longer necessary to use to break this record. Without using the special chassis we leave the door open for anyone willing to duplicate or break this record the same way. |
Photos
You can download a Power Point presentation with pictures about
it here: Pictures
of the World Record Flight - 4MB.
|
finally
If you want more information or send us your opinion and feelings you can contact us by email: Gonzalo.Chomon@Rcmaterial.com |
