Super Sniper

flying saucer · January 20, 2013, 04:09:22 PM

Picked this one up a few days ago. Not really a lengthy build, but there is some finesse and fine-tuning involved to ensure it works and fly's properly. The fuse and vertical stabilizer is fiberglass, the rest is balsa.

Waiting patiently on the work bench is old Panther power system. This one should be fairly light and fast, and will be strictly setup for bungee assisted launch.

It also has a sparkly paint job

Ededge2002 · January 20, 2013, 05:22:02 PM

that should be much faster than the Panther was!

thehaze · January 20, 2013, 06:18:57 PM

The wings are so short, I can hardly see them! You're going to need to keep the speed up for sure.

piker · January 20, 2013, 09:36:43 PM

Very nice, Jeff!

And very sparkly

Ededge2002 · January 20, 2013, 09:53:08 PM

It definatly has an Evel Knievel look to it!

flying saucer · January 21, 2013, 05:46:39 PM

Quote from: Ededge2002 on January 20, 2013, 05:22:02 PM
that should be much faster than the Panther was!

I know, the Panther is a bit of a slow poke. Well at least I can use it as a nice relaxing flyer in between the Sniper and the Rifle..

thehaze · January 21, 2013, 08:14:45 PM

Did you get a Rifle?

flying saucer · January 22, 2013, 11:30:10 AM

Yes, courtesy of Mr. Edge. Its been sitting on the shelf armed with 450watts, waiting for a nice day...

thehaze · January 23, 2013, 02:22:20 PM

450W on a Rifle should make it haul a$$!

flying saucer · January 23, 2013, 08:49:39 PM

Sniper is nearly finished, but will probably have to order a small capacity zippy compact 6S, as this model is designed for and usually flown on 3-4 cells.
Just need to adjust a few things and add a satellite rx.

Couple more pics:

sihinch · January 23, 2013, 10:57:47 PM

I'd go 8S Jeff, to overcome the drag from those servo horns and control rods!!!

flying saucer · January 24, 2013, 04:15:51 PM

I don't think that will do much good, I did a watt test with the fan unit installed. I'm getting over 500watts less in this airframe vs. the Panther.

Seems large cheater hole(s) are a must when using high power setups, or you need huge intake ducting.

The good news is it's only pulling 53amps, so at least my flight times should be decent, although I'm hoping the power may increase in flight due to ram-air effect?

sihinch · January 24, 2013, 05:24:24 PM

Jeff - you missed a great workshop last night, on power systems. Your lower "watts" figure means it's consuming less power, not necessarily making less power. It could be that your installation is more efficient this time.

Maybe Ed can shed some more light on this?

Ededge2002 · January 24, 2013, 07:55:24 PM

Ugg ducted fans... a proverbial vacuum of efficiency!

The fan is likely unloaded or stalled due to poor ducting. Having internal ducting would smooth the airflow into the rotor and vastly improve its performance. I don't much EDF stuff but I believe there is a calculation based on fan sweep area/ intake area also. High blade count fans might make airframes designed for 6904 style rotors worse.

flying saucer · January 24, 2013, 10:13:41 PM

Quote from: Ededge2002 on January 24, 2013, 07:55:24 PM
Ugg ducted fans... a proverbial vacuum of efficiency!

The fan is likely unloaded or stalled due to poor ducting. Having internal ducting would smooth the airflow into the rotor and vastly improve its performance. I don't much EDF stuff but I believe there is a calculation based on fan sweep area/ intake area also. High blade count fans might make airframes designed for 6904 style rotors worse.

Hey Ed, this model actually has full internal ducting. However as you mentioned, the problem I think is that it is simply too small to move the required volume of air. Seems like it was originally designed for 600-800watts using a 4cell setup. I'm still getting over 1000watts out of it, but the fan is definitely starving for air, similar to the Panther before I gouged out 2 large cheater holes in front of the fan. To make matters worse the exhaust exit diameter is only about 53mm. This further reduces static thrust which should be about 80% of total FSA.