Consider this post by the respected DIY ESC developer Takao Shimizu, talking about a low cost controller available from a popular vendor:
The money quote:
But, when it's over the current (>2A), then the output voltage goes up to the input voltage(11.4V).
Read that carefully: if you overload the ESC (and 2A isn't that much of a load), your 5V supply suddenly becomes an 11.4V (or higher) supply. Think about how much you have invested in your receiver, servos, autopilot, GPS, OSD, camera(s), etc. Many (most) would be destroyed more or less instantly by a surge of that kind.
It's not just power supplies, though. Cheap servos are tempting too, but again they represent a single point of failure for your aircraft. If you're just building a foamie with an anticipated flying life of a few months, you might be willing to accept the occasional failure and early demise, but if you're flying several hundred dollars worth of gear, a few bucks more for decent servos is a much better investment.
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It will be a fun and expensive process learning which underestimation is larger between my caviler assessment of the difficulties of ballistic parachute deployment and my assessment of the ease of airframe design.
Particularly seeing as I haven't flown an RC plane since I was 12 and my hours behind the stick of a Cessna can be counted on one hand.
Hopefully wishful thinking and optimism will carry me through to victory, and when that inevitably fails:
I'm an unrivaled expert at moving goal posts. :P
I'm already psyching myself up for the purchase of a foamie ducted fan RTF airframe, and the subsequent process of adding bubble wrap, rubber bands, and duct tape until I can drag my flying piece of styrofoam behind a truck without losing any valuable flight control mechanical/electronic/electrical goodies.
If that fails to tear the wings off: I'll have to resort to throwing it at trees until it's earned the honor of a failing a "destructive test." Afterall: why wait for disaster to come to you when you can go to it?
More likely, I'll get emotionally attatched to my disposable airframe and I'll just have to test it's durability the old fashioned way: I'll do my very best to shelter it from pre-flight check oversights and destructive testing will come to me before I'm ready to say goodbye.
A cheap RC model chute in order to work typically should be folded-unfolded before flight...
A lot of work. So much easier to run your plane on the ground for 1hr and count failed screws, batteries. If you don't care about this static test (99.9% of small aviators fail to), you have unreliable plane being rushed to maiden flight. Ppl simply tend to think this is fun, somehow. A kind of 'russian roulette'.
I've decided it would be cheaper to built a disposable/bomb proof airframe. I'm gonna strap some wings and control surfaces on a pulse jet in the near future and hopefully I'll come back with something other than my tail between my legs.
Maybe a dead man's switch controlled ballistic parachute/kill-switch combination would provide more security value for the money? Shouldn't be to hard to remove the first stage from an Estes motor leaving the parachute deployment fuse.
The brand often finishes its life by selling lower quality under the brand's popular line, this occurs before market restructuring. Unfortunately most old brands of the western economy reached this point simultaneously.
Rather, I meant to argue that care should be taken in selecting and testing your equipment. In *general* this means that you will find yourself buying and using specific items from a range of vendors with a good track record. If you aren't sure how to evaluate an item, look for others' experience, but always try to learn from it.
Price should not be a determining factor; if you can't afford a suitable component, buying one that's substandard is a gamble at best.
Hah. somehow 6 out of 12 HITEC HS-81 servos bought in Poland were generally faulty: uneven moving or ultra-soft gears. 4 out of 4 bought in France a year earlier (2007?) worked so far for 4 years. I use official Hitec distributor. As long as there are double standards of shipment, you never know if you still have 1st grade equipment.
Recently we began selecting AXI motors for pteryx since some series have quite weak magnet glue.
We use ESC that are rated 6 times more than continuous current consumption and 2 times more than peak current consumption, or else they have thermal shutdowns, no matter the brand.
If things continue like that, RC planes will be flying maybe faster, but only downwards.
At least we have our autopilot so if there is a failure, we are sure we can correct it. At least. Instead of having silent dangers introduced without our knowledge.
I will admit it was not the real CC ICE HV I meant to buy, but it was SO much cheaper, how could I resist?
Good thing my UAV was on the bench and not in the air at the time!
I learned my lesson.. CastleCreations here I come (no more cheating!)
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