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Old Jan 16, 2002, 04:14 AM
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FLY times

Flight times.

This is an often asked question and sometimes much avoided because a model's flight times are based on many variables, especially with complex models such as a helicopters. For this reason only estimates are given.

Type of battery, number of cells, gear ratios, type of motor, blade size, overall weight, how well the helicopter is trimmed, etc., are some variables that can affect a model's flight times.

The House Fly pulls anywhere from 1.5 and 3 amps, teather or with on board 1.8 ounce 'starter' NiCad 150mah battery as stated in the HF specs, you can expect about 3 minutes from the suggested NiCAd.

This may not sound as much, but remember that these numbers are based using a starter battery and standard off the shelf components and stock motor, which can be hoped up, as many modelers do with basic starter model kits for added performance and longer flight times.

Please take above numbers as a good estimate and keep in mind changes in any of the variables will give more or less.

The House fly was designed to take advantage of the new Lithium Ion and Polymer cells, but since this is new technology, as is the House FLY design itself, we don't have all the data just yet, but we are working on it and as soon as we have solid information we will let every one know how this new battery technology works out with the House FLY. Our guess is optimistic and some modelers may have already tapped into this new technology with similar RC ultra-light indoor models.


Mario
www.micro-flight.com
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Last edited by Mario; Jan 16, 2002 at 04:21 AM.
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Old Jan 16, 2002, 05:26 AM
jk
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Mario,
only 3 minutes???!!!
that's a bit disappointing to me, but i appreciate you giving out the info. it at least gives a figure to play with to see if we've got our flys in the ballpark. if you hadn't furnished the estimated flight time, some might have thought that they'd done something wrong. i realize that this is a + or - figure, but i'll have to see if i can do something about that .

i hope to have mine flying by this weekend.

thanks,
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Old Jan 16, 2002, 06:08 AM
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and how exactly should they be hopped up? never heard of a brushless gws-size motor for use on 6v... and why is the 150ma pack a 'starter'? you can pull this amperage with 2/3AAA's 300 nimh's, why isn't this stock?

I don't see why people with 300mah nimh packs are running out so soon, unless 3 minutes is an exaggeration on 150's...

I don't understand why you're running a power-hungry n20 as a tail rotor, there are a lot of other options that would save power and weight...

things to try: geared cloud 9 pager motor for rotor
gws edf-50 motor for main motor, same power on less cells (hotter motor)
power source? hmm. 3 amps max, huh? anyone tried 2xqc 830's? should weigh the same, might be able to get about 600ma worth out of those current ranges... if you go with the gws edf motor, might be able to even use just one 830...

I don't know too much about choppers, just trying to apply what I have learned about microflight power systems... mario, want to send me a housefly kit for power system optimisation? I'm working on a dc converter that would allow these current levels, and I have lots of ideas... I'm an EE btw...

is the housefly cp or fp, or is it an option? what's the pitch/diameter and gearing?
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Old Jan 16, 2002, 06:36 AM
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John,

I am sorry to dissapoint you.

Considering it uses inexpensive basic components, what sort of flight times did you have in mind.

Mario
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Old Jan 16, 2002, 10:44 AM
jk
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Mario,
i was hoping that the kit would at least get 4-6 minutes as all of the other micros do. it's seems a little strange to make a kit that's supposed to "take advantage" of cells that aren't fully or actually being used yet. i'm not criticizing the kit as it looks nice (afterall, i bought one), and i intend to work on getting at least 5 minutes out of it, using readily available cells and the stock GWS motor.

when i was working on the shrinking of the Piccolo (Moth) and the Hornet (Gnat) it took me a while but i got both of them to eventually fly for over 7 minutes. at first, i could only get about 2.5-3min out of the Moth (with a brushed motor) but eventually i got it up to 4.5 (w/a180) and 7+ with an AF010.

if you haven't tried the Hacker B20-26S or B20-31S, i think they might be a more suitable brushless option since they're so much smaller diameter than an AF010 and would probably fit in the same location as the GWS stock motor). i'll order one and try it after i've exhausted my flight time tests with the OEM motor.

thanks,
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Old Jan 16, 2002, 10:56 AM
ruf
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Astro 010 - 32g
Hacker B20S - 40g
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Old Jan 16, 2002, 11:16 AM
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Disclaimer, I am in no way posting this to flame ANYONE so do NOT take it that way. I'm simply throwing out some ideas which may help someone. Like I've already said, I really like the way the Housefly looks and would like to get one if it proves out.

150ma at 3amps = 3 minutes. However, you won't be able to fly all the way to the end of the pack. Probably 100 to 125ma is all that can be used to fly. Thus flight times may only be 2 to 2.5 minutes.

Isn't 3 amps kind of high for a heli this small? I would have expected 2 to 2.5. I hate to sound like a broken record but could it be geared too high? It sure makes a difference on the Robin 300 when you gear it down. If the GWS motor isn't allowed to spin up due to gearing, you will have to really sock it to it so to speak to get the rotor rpm you need. The Hornet is really geared down and look at its flight times.

I remember once I had a little RC car. It had two pinions. I put the larger on since I really wanted it to go fast. Well, it did ok. After driving her around some, I decided I wanted to do donuts (hey, I was young). I put the small pinion on. It was amazing, the little motor was allowed to spin up and the thing probably went twice as fast. I mean it was a dramatic difference. Given that the Hornet is geared down so much more than other micros and given that it swings more blade than the others but still has longer flight times, I must wonder if we are not gearing our little helis right.

Unless we do a dyno test and matched the gearing/rotor combo based on this data, we have no idea if a heli is optimized. Any plans for a small homemade dyno floating around????

Mario, did you match the gearing based on dyno data? It is important that we know how it was designed. If you did we know we don't need to waste time investigating this path. If you did could you post the dyno curves for us to review? If you didn't please let us know so we can look into this as a way to increase flight time.

Just some food for fun thought
John
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Old Jan 16, 2002, 11:18 AM
jk
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so what if it's 8 grams heavier? the hackers have ALOT more available power than the astroflights.

johnk
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Old Jan 16, 2002, 11:24 AM
ruf
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Just tossing some specs out there. Never said the Hacker was bad.

As for dyno, I don't think these motors will mate with my TurboDyno. I love that thing. Let's me know exactly what to gear at for my cars for different powerband setups, tracks layouts, etc. What kind of dyno would you use for such a small motor? Sorry, a little new to this stuff.
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Old Jan 16, 2002, 04:42 PM
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Hi ruf,

You hit the nail on the head with respect to why a dyno is so important when setting up something. I bet it would be just as useful for our little helis, all brands.

With respect to what dyno could be used with a motor of this size, that's the million dollar question and I have no idea either.

Wonder if we could design one that would be sensitive enough? A guy built a small one for a mechanical engineering class while I was in college but to be honest that was a long time ago and I really don't remember much about it.

Anyone???

John
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Old Jan 16, 2002, 05:08 PM
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Hello Guys,

I posted something that applys here {{{{ Read This}}}} This will explain your times and how to get more for FREE!

Bill
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Old Jan 16, 2002, 05:38 PM
ruf
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I could do it, but it would require 2 sleeves. One for the can, to bring it up to 540 diameter, and one for the shaft or shaft adapter. Not a problem as I have a full machine shop at my disposal, but I don't have a ton of motors (being that I'm new to this), and I could NOT test brushless systems.
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Old Jan 16, 2002, 05:43 PM
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NJ
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Ok, all this talk about fly flight times got me curious on how many amps i can get out of my 850 lithiums. Well normally i guess the max discharge is not supposed to exceed 2c (1.7A) and if you do the protection cicuit is supposed to kick in and shut down. Well, this is not the case...... just 5 minutes ago i hooked up my meter to do a couple of quick readings. Under normal conditions i pull about 1.8ish amps and produce about 4.5-5 oz static thrust. Yeah, i know this current is not enough for a hover, but upon applying more load to the motor I was able to sustain about 2.8amps without the protection circuit getting in the way!! This will be my first try for a pack for my fly (Still dont have it!!!!). The pack weighs in at about 1.9oz (its two cells). I'm actually quite surprised that no one has tried this yet. I've been using these packs in my planes and getting ridiculus flight times in the order of 30min or more (i stop just to make sure voltage doesnt drop too much and destroy the pack) I saw another thread where some put some prismatic 600mah cells(2x2config) into a hornet and got 25minute times (do a search on prismatic). Mario, for sure you must have tried lithiums by now......
-curt
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Old Jan 16, 2002, 05:53 PM
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Bill is right but it also makes sense to help everyone by optimizing where possible. For example, what if you don't have a large enough indoor area to fly forward flight? Slow forward flight in the living room or even office at work (this is what sounds cool to me) probably won't help much. Those people will want longer hover times.

Besides, increasing the hover time means all win since forward flight times increase as well. To me this is worth discussion and pursuit.

Cheers
John
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Old Jan 16, 2002, 05:59 PM
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Hey Mr. Spinner, I've been using qc830's with my M100 motor(draws 4.4amps with an 8x6) for around 20 flights and it works great(full throttle for ~5minutes). Somebody try the qc830's in the HF and let us know. The qc830's can take the beating I assure you.
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