craigmel

My Feedback: (25)

I recently purchased a Hobby-Lobby V-Diamond pusher jet....looks alot like a bvm bobcat, or kingcat....Anyhow they suggest a AXI 2212/20 1150kv outrunner with a 8x5 prop....I already own a eflite park 480 bl 1020kv....manual on the park 480 suggests a 10x7-12x6 prop...unfortunately I cannot swing anything larger than a 9" prop due to twin boom design of plane. I was just curious if I can find a happy prop combo for this motor that I already own that will still produce great flying attributes? I would use a eflite 40amp esc, and a 3s 2100mah lipo....everything I have is the same stuff they used except the motor....

Obviously the park 480 that I have turns 130 less rpm per volt applied than the axi 2212/20. Which if I did my math right equates to the park 480 turning 1,443 LESS rpm figured @ 11.1v So common sense says to me that I will need to use a prop that will take a bigger "bite" of air per revolution to make up for the fewer rpms turned to fly the model as well as the AXI 2212/20 with a 8x5. Have I confused anyone yet? Am I looking at the scenario properly? I am kinda green still in electrics a little, I am just wanting someone with experience to verify my ideas, or to steer me in the right direction.

Once again eflite recommends a 10x7-12x6 prop, but I can only turn a 9" max due to width between tail booms....how much do I need to go up in size to make up for any rpm loss over the AXI? Would a 9x6 be a good start??? Or do I need a even steeper pitch? Did try a 8X6 on it and it was very weak on the tourqe...would probably reequire a 100ft (exagerrating) takeoff roll!

Any Assistance is greatly appreciated, and thanks for your time in advance! Whew...I will shut up now! Bye!

Regards
Craig Davidson

craigmel

My Feedback: (25)

The only other thought I have is as follows....I did some measuring and figured out that if I raised the horizontal center line of the motor 3-3 1/2 inches vertical I could clear the maximum 11x7 prop that they reccomend for the park 480...in other words I would build the firewall up in the rear 3-3 1/2 inches above horizontal thrust line, thus giving me the clearance for the prop to swing above the rear tail booms. Is this an idiotic idea? I understand what happens if you move your horizontal thrust line left or right of center of fuse....but what adverse effects can you get by raising the thrust line all together assuming that incidences and all stay as close to possible as original? On a pusher, I can't see it making too much of a differance...however, I don't know everything, just ask my wife Learn me something if you can!

Thanks again!
Craig

cjshaker

I used the AXI and prop that Hobby Lobby recommended on my V Diamond. Seemed to
have plenty of thrust at full power.

Chris Shaker

craigmel

My Feedback: (25)

ordered axi 2212/20 and 8x8 prop (their setup), just hoped I could make a brand new motor that I already had work....oh well...anyone interested in a new eflite park 480 brushless 1020kv???

Fishbone4u

I used Hobby Lobby's exact setup recommendations and had my moter keep cutting off in flight. I just too it into my LHS and they showed that with the HL recommended 8x8E prop I was pulling over 20 amps! The ESC is only 18amps and the motor is only for 6 - 12 amps!
The simple solution was to go to a 7x5E prop and now it only pulls 11 amps max.

How could HL recommend this and how are some people not having problems with an 8x8E?
I have since bought a Wattmeter to keep me in the dark no longer...
I just hope having my motor/esc shut down a total of maybe 6 times hasn't done any permanent damage.

Anybody have any thoughts or recommendations?

Thanks,

Chris

cyclops2

Fishbone.
I guess the same guy is still writing power packages now, that wrote them way back for the Kyosho P-80 ducted fan. A 700 mah nimh was supposed to power it . Power was 5 seconds at WOT. Very warm battery.