flitter B with rudder

[Fwilly]

I added rudder to a flitter B and used a gws c drive on 8 120mah nicd cells. It works great!! On launch it will climb up vertically out of my hand and has strong vertical throughout the whole flight. at full throttle the flights are short but I occasionally stop trying to hold a hover and fly around at partial throttle wich extends the flights but they're still probably under 5 min. motor dosen't get to warm with flights that short. wish the wind would die down so I can practice trying to torque roll. this is the first plane I have had with full vertical. so far I have managed a quick 1.5 rotation torque roll in between gusts(the large prop and low geared motor make it spin quickly)

this is really fun and if anyone else builds a flitter B I would recomend using a c or d drive because the s2 drive I had lying around didn't do near as well.

hope everyone elses day has been as good as mine(heading out for my forth flight in a minute)

[Dave Robelen]

Hi Fwilly,
Since you are on a "power roll", there is still more to be had. I have had very good results fitting the EDF motor to an E drive (10.7-1). Running on the 8 X 120 ni-cd pack and spinning an APC Slowfly 8-6, My Flap Jack has practically gone berserk at full throttle. Like your Flitter set-up, My motor is cool to the touch after a 5-minute flight of varied throttle settings, and the battery stays cool as well.
More power to you, Dave

[Fwilly]

sounds like a good set up for my plane. what thrust are you getting? my flitter came out at 6oz with 8 cell and pico gear(except for the rudder which is a 1/3oz servo I had lying around) I may have to get a pinion puller. doesn't gws have one?

why is the EDF more powerful? is there differen't windings or someting? I've been trying to find the answer to this quetion for a while. I also have a dd plane I would like to try an edf motor in. with the normal motor it will loop and roll well and climbs fast on 8 cells but I would like to cut the battery down to 6 cells to save weight. I recently cut the wood out for a second version and weighed the wood. by using lighter wood and a combination of 1/16 and 1/32 wood I was able to save 3/4 of an oz. If I could cut the battery down to 6 cells and get back some of the power back by using an edf motor I think it woud be an awsome plane. does this sound like it would work? total weight should be 3 3/4oz rtf, the wing area is about 1/2'. the old version weighed about 4.5 oz.
I used a viper prop without the spinner. it used the same battery as the flitter.
thanks
Mike F.

[Dave Robelen]

Hi Mike,
The answer is yes, the EDF motor is wound differently. When used in the fan, it pulls over 3.0A on just 6 cells. It also produces it's best power at a high rpm. This is why we are using such high ratios to let it spin up and unload. It would be bogged down badly in something like an A gearset and normal size prop. With the E gears it will pull an 8-9" prop and produce almost 40% more thrust than the standard motors at about the same current. Im models like the Flitter or Flap Jack, they move around fast enough most of the time to let the motor unload and stay cool. No doubt it also helps that it has carbon brushes.
The EDF motor should be a great choice for a lightweight hob running on 6 cells. The only trick would be finding the best gear ratio. Maybe a B?
Regards, Dave

[Fwilly]

thanks for clearing up the power difference question. A normal gws drive would be to large for the dd plane. it has a fus that is 1"X1" and a regular drive would leave the large spur gear sticking halfway above the top of the fus. does anyone make a planetary drive for gws motors? also the overall small size of the plane dosen't leave room for a large prop(5 inches max) what size prop DD would let the motor unload? I really like the viper prop on the normal carbon brush. it is 4 inches in diameter but I don't know the pitch(I think it's less than the recomended 3" prop)
thanks
Mike F.

[Dave Robelen]

Hi Mike,
I have some strong doubts about any benefits using the EDF motor DD. That sucker is pulling over 3.0A driving the 2" dia fan for the EDF. If you look at the pictures, the blades are mighty skinny, and do not have all that much pitch. Good luck in a planetary drive. If you were to turn one up, a lot of us would be interested.
Regards, Dave

[Fwilly]

while searching through old issues of rcmicroflight I found what appeared to be a gws motor with a planetary. it was on a plane called the profile power house which can be found in the downloadable plans section of their site. after reading the article I found out the motor was called the fire cracker and the gear box was the HY-50F(both available through cloud nine).

has anyone tryed that combination. How close to the gws motor is the fire cracker motor. Think they're interchangeable? Is the fire cracker HY-50F combination any good itself. I'd hate to pay $20 and not have any thing good come out of it. If they are interchangeable is the gear box up to the power of an edf motor?

The HY-50F is 5:1. what size prop would be good with that ratio? I would think that the props that I have been using with the dd normal motor would be about right.

fixin to do a search for the hy 50 f and fire cracker motor on rcmicroflight.com to see if I can't find some dimensions

thanks

[Dave Robelen]

Hi Mike,
I believe the Firecracker is a less powerful motor. Why not E-mail John Worth directly (he is Cloud 9) and get those numbers. His address is on the vendor links page of RCMF.
Regards, Dave

[Fwilly]

thanks good idea.

I also found another planetary that might work for a gws on an mtm humming bird motor at www.mtm-int.com/ these motors are kind of expensive(if I converted currency right they're 35-40 USD)

[Mikerjf]

FYI, I tried the EDF motor dd with a 3x2, draws about 1/2A more than the regular motor with no appreciable gain in rpm. These motor's compare sort of like S280 and S300, the EDF likes low torque high rpm operation (geared).

Mike

[Fwilly]

gonna try 5 to 1 with a 4" prop. I had been using the 4" prop on the regular motor and it worked well.

Dave
have you checked the amp draw on the edf on the e drive with the 8x6? If the 4" doesn't work I want to try to prop it to match your amp draw.
thanks

I haven't gotten an email back from cloud nine but I found an article in rcmf that showed how to adapt the HY-50 to a coreless motor so I am now confident enough to try it. It might be awhile because my truck is in need of repair but when I get some spare cash I will try it and post the results.

[Dave Robelen]

Hi Mike,
Mine checks in at 2.0A running the E drive and an APC 8-6. This obviously drops guite a bit in flight, because the motor stays cool and the flight times are quite reasonable for 120 mah ni-cds
Regards, dave

[Fwilly]

wow only 2 amps. that would still leave the possibilty of lithiums. wish I could afford some of the 2 cell powerflite 570mah packs, but right now all I can afford is surplus cell phone batts.

If anyone hasn't seen the powerflite batteries they are really light for their capacity and are 3.8 volts per cell. 2 cells only weighs 1.1oz. they use some sort of gell encased in plastic which is probably why they are so light. here's their site http://www.bktsi.com/powerflite/batteries.htm#Polymer%20Power%20Bar™ the only problem is they're $70 a pack and the site says they wont work with regular lithium chargers. the special chargers are also expensive. wish I had the $$$$$

[Mikerjf]

Dave;

What prop rpm are you getting with the E drive?

Thanks

Mike

[Dave Robelen]

Hi Mike,
I have not measured it yet. If I can manage it, I will get a number before this evening.
Regards, Dave

[Dave Robelen]

Hi Mike,
Back with numbers. I measure 4500 RPM with a fresh 8-cell pack and the APC 8-6. When I took note that this translates into around 50K at the motor in certain flight conditions I was impressed! I also ran an APC 9-4.7, which hit 4700, but the inflight thrust was well down from what the Flap Jack needs.
Regards, Dave

[Mikerjf]

Hi Dave!

Boy that thing really cooks, 50K wow! I've got an application where I'd like to try it at around 4/1 with like a 6x5. If I mess with it I'll post the results. Thanks for putting your numbers up.

Mike

[Fwilly]

after going back and rereading the Flap Jack construction article I realized my Flitter is a full oz heavier(maybe more). I have some white bead foam and an 18" hot wire bow and would now like to try to make a Flap Jack. I don't have a cf tube to use so I want to try to make a 3d fuselage the same way as the wing(lots of holes and little foam) does this sound like it will be strong enough? another idea I was thinking of is to cut some fanflod foam to about half its thickness and use it to cover the fuselage. What empty airframe weight should I shoot for?
thanks
Mike F.

[Dave Robelen]

Hi Mike,
You have some good options for an alternate fuselage, let me toss out one more. I am fond of making a square balsa tube from 1/16" stock. In this case I would go for maybe 1/2" sq. at the front and taper to 3/8" sq.
The covered wing +ailerons on my model run about 25 grams. The sheet foam tail is about 9 grams. Come to think of it I have never weighed a fuselage. My best one is a chunk of broken fishing pole. A neighbors kid stepped on my favorite Bream pole, but I could not bring myself to throw it out. So now I chop out a length from time-time for these odd jobs. I believe this tube is fibreglass, and not really all that light.
My Flap Jacks tend to weigh right around 140 grams with two HS-50's, a GWS 2A ESC, GWS R4P, and 8 120 mah ni-cds. There really is not that much difference in weight between the various GWS drives in this group. My APC prop is a trifle heavy, but I love the way it pulls, and it is sooo smooth.
Take care, Dave

[Fwilly]

thanks for the weights

any reason to use hs50s over picos? the only differene I've heard of is lower current drain. Found an old broken tiny that I bought at a swap meet to salvage servos from If I can get all the epoxy off I might be able to use its carbon tube,If I can't clean it up I think I'll use your square balsa tube method because it sounds easier.
thanks
Mike F.

[Dave Robelen]

Hi Mike,
I am fond of the HS-50 because of the lower drain, and slightly less weight. The lower servo drain leaves more for the drive motor, and yes, I am picky. The Pico class of servo's would do just fine.
Regards, Dave

[Dave Hederich]

Dave, that's really a fantastic discovery that you made about running the EDF motor with one of the high-ratio IPS boxes. I'm curious as to how you arrived at your combination of an E drive with the 8x6 APC prop. Did you use some kind of formula, make an estimate based on past experience or just go through a lot of trial and error?

The starting point that I'm coming from is the Qualcomm 830mAh Li-ion pack and a Trainer IFO. I'd like to match up the EDF motor with the right IPS gearbox and optimum prop size to fly a T-IFO. We're talking >500 square inches of wing at ~7 oz. I'm just finishing mine up and plan to fly it on the recommended IPS A w/10x4.7 prop for starters. But if the EDF motor with the right combination of gearing and prop will give 40 percent more thrust at less current, we are talking about seriously long high-performance flights with Li-ions on a T-IFO.

With its ultra-low wing loading, the T-IFO should thrive on a combination that produces maximum static thrust with minimal prop pitch. So, I'm guessing that with the 7.2V of Li-ion instead of your 9.6V of NiCd that I might be able to run an EDF motor with E gearing on the same 10x4.7 prop that is recommended for the T-IFO with standard IPS A. Then again, dropping down a full 2.4V might require an even larger prop or perhaps C or D gearing.

I'm trying to get a rough idea of how you arrived at your ideal combination so that I can figure out what would be the best starting point to start looking for the best combination for my application. Thanks for sharing this information.

[Dave Robelen]

Hi Dave,
My starting point for the EDF/ gearing combo was arrived at in a couple of ways. My first shot was to fit the EDF to an A gearbox, and run an APC 9-6 on 7 volts in my wind tunnel. The current was higher (about 2.6A static) and the thrust was up by about 40% compared to the original carbon brush motor.
Meanwhile, I had been talking with Bob Wilder down in Texas where they do a lot of indoor racing. They had found that letting the motor unload with the higher gearing brought the current to a better level, and the thrust was still excellent. Please note that I am running 8 cells with a nominal voltage of 9.6 to turn the 8-6 on a fairly clean airplane. Dropping down in voltage, I would still stick with the high ratio, but go to a lower pitch with more dia. .There will be some testing involved to get the best match with your battery and airframe.
Regards, Dave

[Dave Hederich]

Thanks for the quick response. Based on your input and a little analysis, I think I'll start with an IPS D box, which I already have. The D is 9.66:1 compared with 10.7:1 for the E. The D's 9.66:1 is about 60 percent lower gearing than the A (5.86:1). So, if I go with the same aircraft (T-IFO), same battery pack (7.2V Li-ion) and same prop (10x4.7), then the only changes would be the EDF motor and the D gearing. Essentially, I'd be trading 60 percent lower gearing for the difference in Kv between the EDF motor and the standard IPS motor. If there is substantially more or less than 60 percent difference in Kv between the two motors, then I'd need to adjust the gearing and/or prop size to account for the difference.