Thanks for the info guys. Any chance for a Dirty Birdy comparison?

While electric foamies and park flyers have been a blast to play with, the few e-powered classic pattern airplanes that I've seen were desperately under-powered with really short duration, but that was a couple of years ago. It seems that things are changing rapidly and that the performance gap is closing. Couple that with the rising cost of fuel and the falling prices of batteries, plus the difference in noise levels, it looks like e-power might be in my future.

Thanks Robert and Tony for putting the effort into a real-life comparison and sharing the results. With the credibility you guys bring to the table, I'm really impressed with the results.

Dave

Ready for it's first flight .I'll try and get it in the air tomorrow.Nova Rossi,Futaba.

Originally Posted by pathfinder

Ready for it's first flight .I'll try and get it in the air tomorrow.Nova Rossi,Futaba.

Yes Sir! That otta scoot. NovaRossi power!

Robert

I was able to get to the field today for the first time in ages. I flew the patterns that TonyF posted (thank you again) with my Atlas and Zippy 4000mAh 40C and Zippy 4000mAh 20C batteries. The 40C deliver a little more power but are heavier and the performance is similar with both setups. At the end of the flights, which lasted between 7 and 7.30 minutes prior to the landing sequence, I had 15% left in the batteries according to my checker. This is what I usually have left and these batteries have been going for a couple of years and several hundred flights in my Atlas and Blue Angel.

I'm not suggesting that anyone changes what they are currently doing, but wanted to demonstrate that you can get excellent performance from an electric setup without having to spend $$ on high capacity and high 'C' batteries.

I would add that since this model had it's maiden flight I have changed from an 11x8.5 prop to a 12x8. The 11 inch prop performed similar to a piped 60 at 13,000 rpm. However, the 12 inch prop is so much better suited to the model. It pulls more current (70A vs. 60A) and produces a lot more thrust. This makes the up lines a lot more positive and has the advantage that there is more drag on the down lines too. So, although my original goal was to emulate a glow performance, I have realised that I can get even better performance by embracing the benefits of electric and picking a more suitable prop. During my experimentations, I also swapped the motor (660kV) for a 500kV one and stuck a 13x10 on it. I have since swapped back to the 660kV, but the performance was even better on the lower kV motor and the bigger prop. My conclusion would be that trying to match a glow setup by having the same rpm on the same sized prop is not the best way of using an electric motor in these models.

Originally Posted by Mike Seale

My conclusion would be that trying to match a glow setup by having the same rpm on the same sized prop is not the best way of using an electric motor in these models.

IMHO, you sir are exactly correct! Given the same amount of "power in" or "power out", elec motors will have different torque curve when compared to IC power plants. Usually we can run larger props and obtain better thrust with the electric motors. The problem is that there are a lot of elec motors to choose from. While it is easy to appreciate having choice, it is a bit more work to figure out which elec motors will deliver the performance you want. I am currently working on a couple of Duellist's and considering that the size of the prop is limited by the ground clearance, one ends up running a lot of estimations thru motocalc, ecalc, ect....

Congratulations on a good set up on your plane!

Michael

You will obviously have to limit your prop size on the Duellist, but still might be able to use a bigger prop with more pitch than the original.

I'm running 3 blades on my duallist and while she's not a screamer she flys well. I'll build my next duallist kit into more of a hotrod!