which power system for Mountain Models Tantrum? - RC Groups
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Jun 22, 2003, 07:55 PM
Lance Armstrong- 7 times!
flybike's Avatar

which power system for Mountain Models Tantrum?

Hello. I recently ordered a tantrum from Doug, it is hopefully in the mail now. I really don't want to get a 3d model that doesn't have enough power to have fun with it, so I dont think a brushed motor will work. I can afford a brushless motor. A bunch of people have been talking about Razor motors on here, which size are you guys using? And what gearing? e-tech lithium batteries? Any kind of advice on this topic would be great. thanks in advance, Hans
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Jun 22, 2003, 09:32 PM
Registered User
I too am interested in this question. There is alot of info out there on this subject, but I am having a hard time getting it all together.

I am particularly interested in the Razor 400 vs. Astro 010 question.

My limited understanding suggests that the Astro only wins when using the lightest lipos. The razor, from what I can gather, really wants 3s lipos and moves into the 8+ amp range, where most lipos fear to tread. This may change with the new 20c kokams which are supposed to be coming out.

I am thinking about getting a 2s2p pack of e-tec 700's with a razor 400 to power a variety of 8-14 oz AUW planes. I could probably break the pack down to get a 3s pack for use with an astro. I am confused by the whole thing, though, and don't want to make an expensive mistake.

I feel like my application is right on the edge between wanting an astro or the razor 400. I would probably be near the max capabilities of the astro but not yet getting into the sweet spot of the razor. I looked at the PJS 300 outrunner but that seems to have an even narrower niche application.

I am sick of burning up the little GWS motors. I have bought 5 of 'em in the past 2 months. I could have been halfway to a brushless setup!

Jun 23, 2003, 09:29 AM
Registered User
"This may change with the new 20c kokams "

Don't hold your breath - this has been promised by them before and we got 5C cells. Get the Etecs and fly *now*
Jun 23, 2003, 07:33 PM
Mountain Models Wannabe
CoClimber's Avatar
I didn't get the chance to fly the Tantrum on the Razor 400 with the D drive at SEFF but the C drive seemed to be a bit too much on 3P ETec 1200s. BTW, I'm now stocking ETecs.

Jun 23, 2003, 08:23 PM
Product Manager at Hobbico
GWRIGHT's Avatar
i flew doug's plane at SEFF, and whatever was in it was WAY more than anyone could ever need
I actually think i would have had an easier time with it if it was de-propped a bit. strange, but it actually seemed to have too much power Maybe drop an inch or two in pitch doug and you'd have the perfect combo.
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Jun 23, 2003, 09:34 PM
Lance Armstrong- 7 times!
flybike's Avatar
thanks... this sounds fun.. too much power : )
are any adaptors or pinions required to use the Razor 400 in a GWS box?
i got the tantrum in the mail today, i will be ordering the rest soon...
also, what kind of connectors are you using for the battery?
thanks for the help
Jun 23, 2003, 09:47 PM
Lance Armstrong- 7 times!
flybike's Avatar
Doug, did you mean 3s when you said 3p?
and what prop/box combo works?
thanks, and the kit looks fantastic!
Jun 24, 2003, 02:02 AM
Registered User
Well, you need to use 3s to get the astro 010 really up and moving too.

I'm using 3s1p etec 1200s, astro 010/14 with their new little 3.3:1 gear box, and an apc 11x7 sf prop.

Hot off the charger, it draws 8.5 amps max, which is too much for continuous use, for both batts and motor. But neither mind bursting that power for 30 or 40 seconds.

This is on my cobra, a 3d foamy from hobby lobby. It weight 11.2 ounces all up.

This is radically vertical. I have to throttle back, and it still flies dead slow and stable. It hovers at 4 amps.

And specks out, straight up, at 80 or 90 %.

Don't know exactly how the weight compares with the tantrum.

Jun 29, 2003, 12:01 PM
Registered User
I was with Doug at SEFF when Gary flew the Doug's Tantrum. WOWW! I had to have one and now can't wait to get it built. Thanks for the great deal Doug.
Jun 29, 2003, 12:28 PM
Registered User
Gary with Doug's Tantrum
Jun 29, 2003, 12:38 PM
Registered User
I had a little trouble resizing the picture, this was the best I could do.
BTW Thanks a bunch Gary for all your help with the Magic, I still owe you that cranberry coctail! Sorry again about the aileron mix-up on the Magic.
Jeff Auclair
Jun 29, 2003, 01:46 PM
Registered User
Hopefully this one is better.
Jun 29, 2003, 09:51 PM
Registered User
I e-mailed these pics to Doug at Mountain Models, much better copy of pic on his website.

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