Need Help!..

[mike nill]

i bought a fire fly 4/1 motor at the last AMA show and ive been having troublr trying to find a prop for it.the instructions say to use eather a 4x2 or a 5x3 prop.now heres my problem, on the floting cube (plan of the month)it uses a fire fly 4/1 motor ane a 20x10cm prop :confused: i thought i had to buy a 16/1 motor for this prop.if the 20x10 prop works withought burning up the motor then im gonna have to get one but i dont wanna pay 20 bucks for a cabon prop just to detroy a $60.00 motor :confused: can anyone please help? please! :(

[ 09-21-2001: Message edited by: mike nill ]

[GWS4CEO]

GWS has a lot of different choice of gear-down IPS or EPS, also many direct drive motor with match props. Pls see detail at:
http://servoman.hypermart.net

There should be a lot of useful datas for your choice to match your model. Pls feel free to contact GWS if any could be helped.

[mike nill]

well i already have the motor so im not gonna buy another one.but thanx anyway.i just need to know if the 20x10 works on the 4/1 firefly motor or not.also i looked at my lite-stik motor and its way overkill my plane im working on only has an 18"wingspan so the gws would be way to big and heavy.i plan on using the GWS on a scaled down wanderer 30".

[ 09-22-2001: Message edited by: mike nill ]

[GWS4CEO]

Dear Mike,

Sorry for my don't understand your " fire fly 4/1 motor" and 16/1 motor? Due to that I joint this BB just a few weeks ago.

Although I am very experienced in RC motor system design, I aways keep learning something new from help other modeler to find the solution about there " problems ". :D

During GWS designed our IPS, EPS, Direct Drive motors, my engineers spend many years with thousands test and experiment with a great numbers of sample motor, gear drive, and props under veriaty combinations.

I really like help you to get a best result, wonder why? :rolleyes:

During my teenage, I was newly in RC, my basic understanding of RC was so little. But I learned from a lot of Americans Rc flyers who served in US NAVY and AIRFORCE, they stationed in Taiwan. I enjoyed a wonderful teen age with them. I loved them so much, due to their helps, saved my time and cost to open the door of RC world!

Pls don't be hesitated to let me know how to make your investemnet to be alife again! GWS wish RC modeling is a way of " ENJOY" your life, but not suffered and feel disappointed if some one sold you products but ignore to assist you to use them in a properly way.

Let's find out a best way to use what you got in hand. This possible help other flyers who had same question in heart but dare not to ask! :D

[mike nill]

the motor is an astro flight motor with a 4/1 planetary gear box.i have a question about the castle creations pixie 7P.is it a good ESC for coreless motors?if so then i need one for my firefly.

[pease1]

I believe that the 7p is not high frequency. I think you need a JMP9 ESC or equivelent.

You can use the Pixie, but it will burn out your motor much faster.

[gjohnson]

Mike,
Go to Todd's models. He carries all the GWS props. Buy the ones close in size and pitch to the Westech carbon prop. They are only a couple of bucks each, so buying each size is not a problem. Todd also sells the BMC adapters. One of these is for a 2mm shaft (which is what the Firefly has) to a GWS prop. I've put these on and it works well. The weight difference between GWS props and Westech carbon props is not as much as you might think. I have all the GWS props and the Westech as well (not sure at the moment which size). If I get a chance I'll weigh a few and post the weights. I'm sure you can find the right GWS prop to put on your Firefly.

Also, call or e-mail Castle Creations. A few months ago he told me he was coming out with a high frequency ESC version of the Pixie 7 which would cost about half the JMP HF9. I have the HF9 and it is at present the best for your Firefly (I asked Dave Lewis and Todd Long before I got mine). But, if there is a high frequency Pixie, it may be a more cost effective choice.
--Gordon

[ 09-23-2001: Message edited by: gjohnson ]

I just went downstairs and did two very quick static tests. At 5 volts, my Firefly 4:1 with a GWS 9:4.7 prop generates 47.7g of thrust. At the same volts with a Westech 9:5 carbon fiber prop it generates 49.9g of thrust. This indicates to me that you should be able to fly the floating cube using the GWS prop.

This was very quick (didn't even write down the other measurements since I don't have my tach set up yet), and is a static test only. I saw on the Ezone BB that someone said a particular GWS prop tested well on a static test, but flew terribly. The equivalent Braun carbon prop flew great. Some people completely disregard static tests because the prop is not unloaded the way it is under flight. Other people maintain that static tests tell us something. I think for slow flyers they tell us something. Recently a discussion on Ezone had people estimating that a prop uloads between 5 and 10%. I just don't know.

Hope this helps.

Gordon

[ 09-23-2001: Message edited by: gjohnson ]

[mike nill]

wow thanx for the help i finally got the answers i needed.i heard about the new ESC castle creations is coming out with the guy told me it would work for my firefly and cost half as much as the JMP,about $34.00 he said.thats a lot better than $60.00 :eek: one quetion though ,how come the instructions say to use a 4x2 prop when a 9x3 works that good?also i think the reason im confused is i thought a 9x3 would be used on the 16/1 not the 4/1 gear box.mabe the 16/1 uses a really big prop :eek:

[ 09-23-2001: Message edited by: mike nill ]

[GWS4CEO]

Dear Mike,

Here is some information from "Astro" about firefly motor:

The Astro Firefly SmCobalt Coreless motor. Designed for indoor flying. Motor with gearbox is 10mm in dia and 39 mm long. The Motor is available with two planetary gear boxes. Motor with 4:1 planetary gear box (p/n 799) and motor with 16:1 planetary gear box weighs 12 grams. On the 4:1 gear box use a 4.5x2.5 prop, on the 16 to 1 gear use a 8x8 prop. Motor Kv=4333 rpm/volt. Winding resistance 2.1 ohms, No load current draw 25 ma. This motor requires a special speed control like the Astro Model 200.

GWS also made some high frequency ESC. GWS ICS-100 at 5 Amp ( other company said 7 Amp. )rating should be able to hand this cute baby. If you measure at 7.2V DC, current is read less than 2 Amps, ICS-50 would be enough.

GWS has a lot of props can be match to this motor. Pls check with your favorite dealer.

If they can't provide you this information, ask them to contact Balsa Products, Horizon, or Maxx Products!

Good Luck.

[gjohnson]

Mike,
I'm not sure the 9-inch prop is best. I just did it as a comparison between a GWS and expensive Westech prop. That is the only size I have both for. Also, I only skimmed the article on the flying cube. But, I think he used the Firefly with 4:1 gearing and the Westech carbon prop (can't remember which size). So, it seems he is using a prop this big with that motor.

I plan to do more static tests with most of the sizes of GWS props when I've got my tach hooked up, and the Firefly will probably be the first motor I test. I'll post results when I have them. It's taken me a while to get going because I finally bit the bullet and purchased a good continuously variable DC power supply. Now I'm in business.
--Gordon

[Ralph B]

Mike:
Astro recommends the smaller prop on the 4:1 Firefly because you have to keep the current limited to one half Amp(500 Ma.) max. in order to not damage the motor. While the 4:1 motor might pull the 9 inch prop it will be pulling so much current that the motor will fail very quickly. Astro makes a speed control for this motor which has a current limiter incorporated into the circuit which protects the motor from overloading. Cloud 9 offers this Firefly ESC for $30.00.
Ralph B.

[gjohnson]

Mike,

I checked the RCM floating cube article. He uses a 20cm x 10 carbon prop, 8.8"x4.7". So, the GWS 9x4.7 is closest. Maybe he is in danger of burning out his motor. I bought my Firefly to use in my Flying Aces Stick and don't want to use a huge prop because torque could be a problem. So, I plan to test it with the new smaller GWS props.

Todd lists GWS props in 4x2.5, 4.5x4, 5x3, 5x4.3 sizes. I'm sure all of these are ok for the Firefly. These have a 4mm bore, compared to the larger Lite Stik sizes which have a 3mm bore. You can buy a set of GWS rubber adapters that sleeve either side down (I have these). But, you still need some way to attach it to your Firefly. Todd carries a BMC Products 2mm prop adapter. The problem with this is you need a longer screw than comes with the adapter. BMC also makes 2mm adapters to the 3mm and 4mm bore GWS props. Todd and Cloud-9 only carry the ones to the 3mm bore. So you would need to order this direct from BMC (mine haven't come yet) http://www.bmcproducts.com/

There is a thread on Ezone http://www.ezonemag.com/forum/showthread.php?s=&threadid=10993 on coreless motors, some of which pertains to the Firefly. The Firefly is actually a Maxon motor/gearbox http://www.maxonmotor.com/ . Their site has technical specs. It turns out their East Coast headquarters is about an hour from my house. I may try to see if they will sell motors one or two at a time.
These are very well made motors and gearboxes and others may be useful to us. I suspect that some other Astro gearboxes are Maxon's that are attached to Astro Cobalt and brushless drives (but this is just a guess).

I'll post results for other sizes of props when I get them done. Prop sizes which pull too much current are probably to be avoided, although maybe the Cube designer knows something we don't.

--Gordon

[ 09-24-2001: Message edited by: gjohnson ]

[nolasco]

Why not just use the GWS rubber adapter or spinner to attach the 4mm bore props directly to the firefly? There is a 2mm adapter and spinner as part of each set.

The Gunther prop (also sold by Todd) is another prop option. You might want to replace the spinner though with one of those 2mm GWS adapters or spinners for a tighter fit. The Gunther spinner looks better suited for a 2.3mm motor shaft.

Jun Nolasco

[ 09-25-2001: Message edited by: nolasco ]

[mike nill]

i tried the gunther prop on my firefly and it produces quite a bit of thrust.mabe u can test it for us johnson :D the adapter fits perfect with a tiny drop of ca :)

[GWS4CEO]

I just start a new Topic: " How many GWS propllers you recognized?"

Pls try read it, many GWS propellers size was post there. ;) Possible help you to make a right choice.

[gjohnson]

Jun,

Do you mean that the adapter and spinner come with the GWS prop, or with the Firefly. My Firefly came with nothing. None of my GWS props, bought from both Cloud-9 and Todd's Models came with anything. I bought the rubber adapters and rubber spinners separately (they come several hooked together as molded).

Good idea though. Thanks! I suppose the rubber adapter might be a good press fit on the shaft. I'll try it tonight. Won't have as precise alignment as a BMC adapter, however, but may not matter.

By the way, my interest in the small GWS props is that they offer a consistency and range of sizes and pitches that doesn't seem to exist in the various rubber-power props froms several manufacturers that people have been using till now. With the GWS I get one mounting system and the ability to quickly switch to a slightly different prop. In my conversations with John Worth I've suggested that the GWS props may become the standard for indoor and very small fliers for these reasons.

I've got several of the Gunther props. I'll test one of them when I test the GWS props.

--Gordon
]

[ 09-25-2001: Message edited by: gjohnson ]

[nolasco]

Gordon,

I meant to say the rubber spinner and adapter sets sold separately.

Sorry for the confusion.


Jun Nolasco

[gjohnson]

Mike, here are static test results for Firefly 4:1 with various props. I didn't test the 4-inch, and one of my other small GWS props is with BMC Products while he makes some adapters to fit. Jun, the rubber GWS grommets (Todd's Models sells them) worked very well, and also worked in the Gunther. These quick results seem to indicate that it's possible to go up to 6 inch or so diameter props without violating Astroflight's 0.50Amp limit. Next up for tests, DC5-2.4 with 4:1 gearing (and more tests of the Firefly with rubber-power props and the rest of the GWS props).

Prop........Volts..Amps..Thrust(g)
GWS 9x4.7 5.0v 0.96A 44.5g
GWS 9x4.7 4.0v 0.73A 35.7g
GWS 9x4.7 3.5v 0.72A 29.4g

GWS 6x5.0 5.0v 0.50A 30.8g
GWS 6x5.0 4.0v 0.36A 20.8g
GWS 6x5.0 3.5v 0.34A 17.3g

Gunther5.25 5.0v 0.40A 19.1g
Gunther5.25 4.0v 0.28A 12.0g
Gunther5.25 3.5v 0.28 9.8g

GWS 5x3.0 5.0v 0.26A 15.6g
GWS 5x3.0 4.0v 0.19A 10.2g
GWS 5x3.0 3.5v 0.18A 8.1g

GWS 4.5x4 5.0v 0.25A 12.5g
GWS 4.5x4 4.0v 0.19A 8.1g
GWS 4.5x4 3.5v 0.17A 6.3g

--Gordon

[nolasco]

Gordon,

Hmm. The Firefly 16:1 is supposed to be able to produce around 50g of thrust at less than 0.5A. I was kind of hoping the 4:1 version will also come close using a smaller prop.

Your thust figures makes me doubt I can use the Firefly 4:1 as originally planned. Good thing I also have a 5:1 geared DC5-2.4.

Jun Nolasco

[gjohnson]

Hmm, Jun do you suppose I can talk myself into buying a 16:1 Firefly to test? I've held off because I'm not sure I'd use it in any indoor planes. But, it could be a possibility for a small outdoor plane. Problem is if the outdoor plane was a scale plane the prop would be huge relative to scale. Maybe for a Tiny.

I've also been thinking about getting some of the Anything RC props to test as well as GWS, since their cost is somewhere between GWS and carbon props. Any thoughts?

Gordon

[mike nill]

wow! thats a nice chart you have there!:eek:they should put it on the next months issue:) that helps a hole bunch.but anyway guess what i found last night looking at all the venders info,a nice milled prop adapter for the firefly:DNYblimps sells them for 5 bucks

[gjohnson]

I just got my digital tach hooked up. Now any tests I do are complete. Here's the info for the prop that happened to be on the Firefly when I tested it. My web site should be up in preliminary form within a week or so and I'll start putting test results there and post the link here.

GWS 6x5.0 5.0v 0.50A 30.8g 3450rpm

Gordon

[mike nill]

i found out that the cf apc prop fits the firefly nicely.mabe you could test it if you have one.but i think it mabe to big for the 4/1 gearing.but i bet the 16/1 would be perfect.mabe if you cut it down a bit and use less pitch if you get the building jig for it it might work with the 4/1.or mabe we could get them to design a prop for the firefly both 4/1 and 16/1!:)

[gjohnson]

Mike,
Please clarify which props you are referring to. I have most of the APC props (got them from Hobby Lobby). They are grey plastic and the smallest size is 7x4, and they cost about $4 each. The "cf" in your message, does this mean carbon fiber? The bore in the APC props are quite a bit larger than those in the GWS props. It might be possible to sleeve one down using the sleeves that come with the props. But, none of them look like they will take it down to 2mm. When you say they fit easily, what do you mean.

I hadn't planned to test them on the Firefly because the smallest size is almost certainly too much prop for this motor. In terms of cutting one down, you'd probably be better off just using a smaller GWS prop.

I have read that for a given size, like 9x4.7, the APC props are supposed to generate more thrust than the same sized GWS. I got my APC props as a possible replacement for the GWS prop on my Tiger Moth. BMC makes an adapter (which I have but haven't had a chance to use yet) that adapts an APC to a GWS gearbox. I'll first just put the APC on the TM and see if it's easier to loop. I may rig up a GWS motor on my test stand and test the APC vs GWS props.

Give me more information on your prop and how you fit it.

By the way, the GWS rubber grommets are too big for the gear shaft on the old style Kenway's.

[nolasco]

Gordon,

Do you have any Gunther or smaller GWS props? The 6x5 seems to be too much for the Firefly 4:1. Using smaller props would unload the motor and thus allow more cells to be used. Hopefully, that would translate to a higher thrust output.

I have all of the smaller props. Unfortunately I have no way of measuring thrust short of building a flyer (or installing it on my Franken-IFO) and determining how well it flies. I'd therefore be interested in your test results using smaller props.

As for the AnythingRC props, they are absolutely wonderful. The cheapest way to go is to buy the prop hubs, spare blades, and building fixture. In that way, you can build your own props and fix them when they break.


Jun Nolasco

[gjohnson]

Jun,

I have all the smaller GWS props, but a couple of them are with Bill at BMC Products while he makes me some adapters. I also have most of the rubber-power props the Cloud 9 sells. I have just the one size Gunther prop shown in the table above. Now that I have my tach set up I intend to circle back and do a complete test of all the props I have. I think the 6-inch GWS is at the high end of what the Firefly 4:1 should use. I included the 9 inch prop only because Mike had a question and that's the size used on the floating cube.

As I go forward please give my your suggestions and ideas -- which are always appreciated. I have my son's birthday party today so doubt I'll get to any of it this weekend.

Gordon

[mike nill]

sorry about the mix up i meant the ARC cf(carbon fibre)props

[mike nill]

i tryed to edit my last post but now they have this time limit so now i cant edit my last post and i think a time limit is stupid!:mad:anyway ARC also has a 71/2"prop for small motors i wonder if it would work with the firefly:)

[nolasco]

The 7.5" ARC-6 prop is too big for the 4:1 Firefly and too small for the 16:1. The ARC-1 and/or ARC-2 might be more suitable for the 16:1. You could probably build a smaller and lower-pitched prop using ARC prop parts for the 4:1.


Jun Nolasco


Originally posted by mike nill
i tryed to edit my last post but now they have this time limit so now i cant edit my last post and i think a time limit is stupid!:mad:anyway ARC also has a 71/2"prop for small motors i wonder if it would work with the firefly:)