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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Matt Brown on July 13, 2017, 05:17:55 PM
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I got a little ahead of myself assembling my Brodak universal D mount. Never looked at the plans or even the fuse blank. You can see in the pic, it's a bit long! I can shorten it almost enough but not quite. It would still be about 1/4" too long. If I knew it is likely to come out tailheavy I'd go with it but I'm guessing that won't be the case.
So, I'm thinking switch up to a different kv motor and go to some shorter 4S packs like maybe 2200 or 2600.
I chose this motor because I had it in house along with a few 3S 3300 packs. I have a few 4S 2200 packs but no motor to match up.
I saw a few people using similar setups in the setup thread so I'd guess it should work okay.
I considered cutting it down as far as I can make it fit and the notch the LE enough to fit it all together but that would really complicate covering and final assembly.
Any other options I'm overlooking?
By the way, it's a Fancherish Twister.
Matt
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Hi Matt,
I've built many .40 size profile models and as Motorman says, you need a motor like the Efilite Power 15 with a Kv of around 920 to 980 and a 4 cell lipo of 2200 to 2500 or even 2650. The 3300 is just adding too much weight. The motor should weigh around 140~150 grams and the magic prop is the APC 11 x 5.5 E prop. I have a very simple nose system for rear mounted motors and this has worked successfully on all of my profile designs. If you need more photo'sand explanations than those below, then just send me a PM with you email address and I will be happy to send you the info.
The pics are from a take-apart profile model that I built a while ago and the basic idea is really easy to implement. The "engine bearers" are 1/16" ply, and the nose doublers were made from hard 1/16" balsa (the R/C type!) and it is strong enough. I have also used 1/16" lite ply as well, but the hard balsa nose is adequate. Electric motors don't vibrate like glow engines! The velcro wraps hold the battery in place and also the esc and timer on the other side. To cover up all the plumbing, I add a cheek cowl. I have used variations of this theme but the basic nose method stays the same. The motor in this model was the E-Max/Arrowind BL 2820.
Keith R
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Very nice work Keith! I think I'll copy some of your ideas and mesh them with some of Dennis' work on the Brodak mounts. One thing I want to improve is crash survivability of the fuse. Nearly every profile that I've seen crash breaks the nose off at about the high point of the wing.
Matt
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Make new doublers that will go back further. But then the tail starts breaking off. D>K
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Make new doublers that will go back further. But then the tail starts breaking off. D>K
If you build it so strong it will survive a crash it will probably be so heavy it's guaranteed to crash. LL~
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If you build it so strong it will survive a crash it will probably be so heavy it's guaranteed to crash. LL~
Matt,
I think you'll work it out and it'll be fine.
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Very nice work Keith! I think I'll copy some of your ideas and mesh them with some of Dennis' work on the Brodak mounts. One thing I want to improve is crash survivability of the fuse. Nearly every profile that I've seen crash breaks the nose off at about the high point of the wing.
Matt
Thanks Matt. Combining the better parts of other good idea's can work work for sure. My Protron design had ply wing root ribs on the fuselage because the wing halves were bolted on. The model is still flying even after one really bad prang when it got blown out of the clover leaf in bad turbulence. The fuselage did not break however, and this showed that the nose with the balsa doublers worked o.k. Many of my Eze-Pro stunters are flying here in Darkest Africa with the same nose construction, and most of them have hit the deck at some stage because they are indeed stunt trainers. The system is doing the job nicely and is simple and cheap to construct.
Keith R