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Old Dec 15, 2007, 06:49 AM
Winging it >
leadfeather's Avatar
Joined May 2006
9,402 Posts
Smkn,

I came upon this prop calculator and it is very good. Easy to use and takes the guess work out of prop and esc etc. sizing. It calculates static thrust, amps, efficiency and more.

http://adamone.rchomepage.com/calc_motor.htm
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Old Dec 15, 2007, 10:23 AM
medium-sized Lewbowski
USA, CO, Denver
Joined Jan 2005
300 Posts
Smkn,
I just looked at the Blue Wonder on UnitedHobbies website and yes, you will be underpowered with that motor. That is a 9amp motor and is actually very similar to the 28-05 you just took out - just a slightly higher Kv. The max thrust they advertise is 400g (14oz = same as the weight of the plane) which means you have a 1:1 thrust ratio roughly... or in other words, no vertical performance. You need to be closer to a 2:1 thrust ratio for this kind of plane & flying.

For reference - the blue wonder has a stator size of 22x5mm and and a max amp draw of 9A... you need something in the 22x10mm range with a 16A max draw instead... twice the thickness, twice the amps, twice the power (roughly). You want a motor in the 150~180 watt range, but unfortunately many motor manufacturers don't give watt ratings for their products (very annoying) so you are left having to make these calculations on your own.

So, key things to look for when selecting a motor for this plane:
- 150~180 watt output
- 13~16A max efficiency
- 1400~1600 kv rating

..and then of course you want it as light as possible

Your 1000mah battery selection is good as long as it can put out 16amps continuous.

1000mah = 1amp, 1 x 20C = 20amps.. so you should be OK.

Remember that your plane will perform the best if the total flying weight is under 14oz.

A few good motor options...

http://www.hobbycity.com/hobbycity/s...idProduct=5423

http://www.hobbycity.com/hobbycity/s...idProduct=5706

http://www.hobbycity.com/hobbycity/s...idProduct=2109
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Last edited by Maybz; Dec 15, 2007 at 10:55 AM.
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Old Dec 15, 2007, 11:17 AM
CNC Cutter
birdofplay's Avatar
United States, IN, Indianapolis
Joined Dec 2005
8,483 Posts
On my F-22 which is very heavy at 21.7 oz
using 4s1p 1700ma cells and an old plastic 7x6 prop
I'm using this motor.
http://www.rchotdeals.com/Products/r.../A2409A12.html

I saw this guy selling at a local electric meet and thought I'd give him a shot.

Anyway my F-22 at that weight goes totaly Vertical ! while rolling too.
but remember ... thats 4S 1P

My F-14 has a AUW of 13 oz with a 1250 3s1p lipo.
I'm using a fairly small Komodo 257 motor but I wound "special" :-)))
It's not a Perpendicular Vertical plane BUT with a very slight angle
its goes "almost" straight up !

Next Time I'm out I will attampt to insert my Flight Recorder to
get some Amp, Volt, Watt measurments on both machines.
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Old Dec 15, 2007, 11:29 AM
Registered User
smkn951's Avatar
United States, HI, Kapolei
Joined Jan 2007
1,440 Posts
thanks MAYBZ, i just ordered more stuff. hopefully it gets in soon.
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Old Dec 15, 2007, 11:37 AM
medium-sized Lewbowski
USA, CO, Denver
Joined Jan 2005
300 Posts
Quote:
Originally Posted by smkn951
thanks MAYBZ, i just ordered more stuff. hopefully it gets in soon.
Cool, what did you decide on?
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Old Dec 15, 2007, 12:13 PM
D'oh.. Dumb Left Thumb
dekan's Avatar
London, UK
Joined Nov 2006
5,398 Posts
150-200W motor = 40grms +
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Old Dec 15, 2007, 12:40 PM
Registered User
Joined Sep 2004
82 Posts
I was hoping to use this motor from BP Hobbies?

BP A2212-6 Brushless Outrunner Motor
For 2-3 Li-Poly Cells, 5 x 5 to 7 x 5 props, up to 28 amps. Use on planes from 10 to 35 oz. Designed for high speed flying wings and pusher jets. Includes radial mount accessory package. $15.95

I have a couple of 11.1v 2200 packs that I hope are not to heavy
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Old Dec 15, 2007, 02:10 PM
medium-sized Lewbowski
USA, CO, Denver
Joined Jan 2005
300 Posts
That is a good size (22x12mm) but you will have to run a smaller prop because of the higher kv (2100). The end result is that you will likely get higher top speeds in horizontal flight but less vertical performance and slower acceleration. I currently have the A2212-10 in my Mk1 - the same motor but with a lower kv (1400) and able to turn a 7x5 or 7x6 prop easily. It is the fastest setup I have flown yet and can still run from a smaller 1320 pack.

So it really comes down to how you want to fly the plane.. a higher kv motor and smaller prop will give you more top end speed but less low-end 'grunt'. A lower kv motor swinging a larger prop will give more grunt which means quicker acceleration and better vertical, but your top speed will likely be less. Of course you could try and get the best of both by putting a large prop on a high kv motor - but then your amp draw will go up and you will need a bigger battery to feed the monster.. which means higher flying weight.. which means less vertical performance.... and so on. I like mine light and floaty because they are more aerobatic... and tend to survive crashes better.

All that being said, I'd love to hear how it flies with your suggested setup!
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Last edited by Maybz; Dec 15, 2007 at 03:55 PM.
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Old Dec 15, 2007, 03:18 PM
Glitch
kauai, Hawaii
Joined Aug 2006
534 Posts
Ok all you MDC F14 lovers out there. The MDC F14 is in second place for "foamie of the year". Have you voted yet? If not cast your vote for the best foamie, swing wing, easy to build, kick butt parkjet of 2007.

SS
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Old Dec 15, 2007, 03:29 PM
Registered User
Joined Sep 2004
82 Posts
I want the lower grunt and no need to do 80+ mph.

I just installed this set up on my Wattage F22 Raptor swinging an APC 8x4 drawing about 16.7 amps with 9.6v NiHi. I have the 6x4 and the 5.5x4 but I ordered them in reverse rotation and when I put them on, turned around, it only drew 10.5 amps. So I put the 8x4 off the Electraject and the thrust was significant! I also put a 7.5x4 on and the amps was about 14.5 or so.

I haven't flown it yet, there's a Nor-Easter coming on the East coast and I'm going to AZ for a week tomorrow I want to mirror the power package on the Electrajet once the right prop is picked and then I have to trim the battery tray in both planes for the 11.1V 2200 LiPo.

A few more questions, pls. Is the 11.1v 2200 too heavy for your F14? I have two and would like to use them instead of buying 1200 or 1400.

With all the glue you're using during the assembly, how do you separate it should you have to make repairs due to a too lowflyby? It's not a conincidence it's my login name

Will the planes ship in time for xmas?
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Old Dec 15, 2007, 03:31 PM
Registered User
Joined Sep 2004
82 Posts
Quote:
Originally Posted by Stephen Shioi
Ok all you MDC F14 lovers out there. The MDC F14 is in second place for "foamie of the year". Have you voted yet? If not cast your vote for the best foamie, swing wing, easy to build, kick butt parkjet of 2007.

SS
I gladly and respectfully voted.
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Old Dec 15, 2007, 05:35 PM
RobbeUK & Midland Helicopters
United Kingdom, Rushden
Joined Dec 2005
113 Posts
Quote:
Originally Posted by heymak
If you think this is the best go here and let your voice be heard...

2007 Foamie of the Year Vote for most interesting design

http://www.rcgroups.com/forums/showthread.php?t=783876
My votes in place now, this model rightly deserves to win.

Flew mine today for the first time, bit windy in the UK for such a light model but it flew straight out my buddies hand. However I dont think I have quite got the C/G right as when I killed the power the nose goes straight up. Landed the first time to adjust the battery position which was better, but the second one I got caught out by the wind and broke a taileron.
All glued up now ready for another go.

On the subject of motors my 2200Kv motor on a 6x5.5 prop works well, but I may take some ideas from here and try a lesser Kv at some stage to feel the difference.

Ian
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Old Dec 15, 2007, 05:37 PM
medium-sized Lewbowski
USA, CO, Denver
Joined Jan 2005
300 Posts
Quote:
Originally Posted by lowflyby
A few more questions, pls. Is the 11.1v 2200 too heavy for your F14? I have two and would like to use them instead of buying 1200 or 1400.

With all the glue you're using during the assembly, how do you separate it should you have to make repairs due to a too lowflyby? It's not a conincidence it's my login name

Will the planes ship in time for xmas?
Lowflyby.. To answer your question I decided to take a quick trip to the park. I took the Mki with the BP2212-10 motor and APC 7x6 prop and put a TP 3s 2100 pack in it. Balancing was no problem with the battery sitting just in front of the RX. The plane launched an flew just fine but I did notice a difference. It's definitely faster with the BP motor and with the addition of the heavier pack, it seemed to behave more like a parkjet. It is fast and stable. Still easy to launch at 3/4 throttle and still slows down to a crawl.. but it does take some time to slow down now, and I also couldn't get it to parachute... it kept wanting to fall off on a wing. Vertical was still pretty good although not unlimited.

Regarding glue, I haven't really had any issues getting things to come apart when needed. Sometimes the the foam will break or tear but it usually is invisible once it's glued back together. I augured into an asphalt runway at full speed inverted and ripped the front end off once.. but it only took a few minutes to glue it back together.

I will do my best to ship out before Xmas but I can't guarantee it.

m
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Old Dec 15, 2007, 05:46 PM
medium-sized Lewbowski
USA, CO, Denver
Joined Jan 2005
300 Posts
I also want to thank Bigbadbob again for his autosweep programing tips. The more I fly with it the more I love it. I highly recommend anyone with a computer radio to give it a try.

I stumbled onto another trick today thanks to the autosweep... I was screwing around with vertical torque rolls and found I could pull into a WOT vertical climb with full hard L aileron (working with the torque).. then with the plane rolling at a ridiculous rate I could climb out a bit and then kill the power... the wings would swing open, stop the roll immediately and bleed off almost all of the airspeed. With full up elevator I could then go right into a parachute and float back down for a repeat.. This one is first on my list for the next video I promise. It's very addicting.

cheers
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Last edited by Maybz; Dec 15, 2007 at 07:27 PM.
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Old Dec 15, 2007, 07:11 PM
Vietnam Vet US NAVY
Captainrandy's Avatar
Joined May 2004
301 Posts
Where do I Vote?

Maybz, These are also an awesome little motors. I am currently using two of them, One in the Yardbird Mig 22, and the other in the SU-27 XXL, both are running a 7 X 5 prop, and preform Fabulous. Nice vertical and nice speed too.

https://www.unitedhobbies.com/UNITED...idproduct=5655

https://www.unitedhobbies.com/UNITED...idproduct=2110
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