Aeronaut 6.5x4 or 6.5 prop for Zagi 450T ? - RC Groups
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Oct 25, 2001, 12:25 PM
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Aeronaut 6.5x4 or 6.5 prop for Zagi 450T ?

Oooh, I just gotta get my hands on a 450Turbo for my 400X! If I can find one, that is.

A few people here have reported success with the 1700AU's, despite the fact that it's a bit abusive on those packs. I'll be ordering a couple 1400AE packs, but I'm willing to sacrifice a 1700AU pack for the experiment.

I'd like to prop for less amp draw, for obvious reasons. So, which will draw less current, the 6.5x4 or the 6x5 prop? Any other recommendations for a prop that may be even a tad less electron-hungry? Obviously, I'll be sacrificing performance a bit until I build up a stock of 1400AE's & 800AR's.

Thanks for helping fill a gap in my limited knowledge of prop theory.

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Oct 25, 2001, 01:08 PM
AMA 697691 / FAA 13675
Hi Chris,

The main difference between those 2 prop sizes is that the 6.5x4 will provide a little more thrust and the 6x5 a little more speed.

Since you'll find that you'll have plenty of speed with the P450T, I would opt. for a little more thrust which helps the Zagi take-off better and slow fly around the field a bit easier.

As for the 1700AU pack, keep your speed "fix" to 30 second bursts and spend more time throttled back to 1/2 or 3/4.

You won't see the full power potential until you get another pack because the 1700AU cells just can't deliver the 18amps needed.

Good luck!
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Oct 25, 2001, 04:48 PM
Registered User
I haven't tried the 6x5 so I can't comment on it, but I can say that the 6.5x4 is great with the 450T!

The zagi is a whole new aircraft! Climb is steeper and faster, penetration is better due to extra weight of motor, batteries and prop adaptor, glide is still great as wing loading is still very low, top speed is vastly improved - need I say more?

As Greg says, though, you won't unleash the true potential of the motor until you have tried it on some more powerful cells.

The only limiting factor in deciding between the two props, I suppose, is how far apart your servo control rods are, and therefore how wide a prop cutout you can make in the elevons - you may find that only one prop will actually fit! Hopefully, though, this won't be a problem for you.

Just one thing: make sure that you install a spar into this beast! Some people have found this out the hard way . . .

Ben C
Oct 25, 2001, 07:36 PM
Registered User
Having experimented a long time with my 450 Turbo, I dscovered that the APC 6X4 electric prop is good...but the APC 7X5 E prop is absolutely incredible!!!! It doesn't seem to shorten the flight times significantly, or at all from what I've seen, and with 800 AR cells, this plane really screams! Give these props a try, they really make a difference! My only warning is that due to the larger size of the prop, watch out on landing to make sure that the prop is parallel with the wing itself so as to reduce chance of prop breakage and shaft bending. The other day, I brought her in nice and sweet, you all know when the Zagi is about to land on soft grass and you give it that last little flare up and the airspeed drops to nil...I love that feeling!!! Anyway, I brought her in about as soft as a Zagi can go, and the prop barely snapped at the end because I forgot to align it properly!!!
Also, if you don't have an ESC already, I would suggest the Great Planes 30, It is the BEST ESC I have ever had!!!!!
Happy Landings!