View Full Version : Direct Drive Speed 400 props

09-14-2005, 07:09 AM
I have a slightly up scaled (900mm) Mugi which I keep in my car and fly most lunchtimes (www.mugi.co.uk (http://www.mugi.co.uk)). For those of you who are not aware of the Mugi, it is some of the best fun you can have with a brushed motor!:D

It has an Aeronaut 6V speed 400 with a 3S 2200mAh Polyquest pack. I started with a Gunther push on prop as suggested on the Mugi site, which worked really well. I then upgraded to the carbon 5x5 prop which is a copy of the Gunther, with a slight improvement in performance. I have been flying with the carbon prop for over 6 months now.

Anyway, a week ago I bought a GWS 5x4.3 prop just for fun. I didn't expect it to work very well, but it is always fun to experiment and try something new.

Well we tried it out today and the results blew me away! It is much quieter, and flies at a faster speed for the same given throttle setting. This meant that I flew it at around 50-60% throttle most of the time, so the flight time was also noticeably longer. I expect that there would be a reduction in thrust, but it was not noticable in the flight performance.

In these days of brushless everything, it is easy to forget that you can have a heap of fun with a low cost brushed system.

Does anyone else have some learned wisdom that they can share on this subject?

Sky Sharkster
09-14-2005, 01:27 PM
To Dimadee, I agree that the "Brushless Revolution" has made many flyers scorn the "can" motors but as you said there's still a place for brushed motors and I believe they'll be around for quite a while. One Propeller brand I've had good luck with on small racer-type models is "APC" sizes like 5.25 X 4.75, on 7 Nicad cells they will really wind up. They (Landing Products) have a good selection of sizes between 6" and 4.25" Diameter. Also, if you are interested in E-Powered gliders, the www.charlesriverrc.com (http://www.charlesriverrc.com) site has a complete download for modifications to the Graupner Cam 6" X 3" folder, some sanding and shaping will increase efficiency and RPM. The "Speed 400 Limited Motor Run" (LMR) class of gliders are popular and inexpensive, many kits and ARFs available from Esprit, Northeast Sailplane, laserarts and ArtHobby. Also many good warbirds for Speed 400 from Jim Ryan, these have sheeted foam wings and balsa fuse/tail construction. Yes, I've got AXIs and Hackers but still find a use for brushed motors. It's all fun! Good luck and keep flying! Sky Sharkster

09-14-2005, 03:21 PM
Wow it is impressive that you ahve not cooked that 6v motor with a 5x5 prop and 3s LiPoly. Maybe I will have to play with that a bit.


Sky Sharkster
09-15-2005, 01:43 AM
Hi Mike, yeah, I cook'em, just not as many now that I fly LMR. With a 40-60 second motor run, a half-dozen flights per weekend, they last a few weeks. I've been running the 6.0 but have tried the 4.8, broken in underwater and re-timed. These last about 10 flights before there's a noticable dropoff in power. I'm working on an Art Hobby "Agena" now, conventional tail, will run the 4.8's in that for 7 cell LMR. I've also got a Dynaflite "Skeeter" (HLG) converted to Electric 400, pretty good R/E/T inexpensive starter LMR plane. I would like to pylon race a 400 class but there's a lot of disagreement about " How many cells" "Can I run LiPos?" etc. If the rules ever catch up with developments it might happen! Sky Sharkster

09-15-2005, 06:41 AM
Wow it is impressive that you ahve not cooked that 6v motor with a 5x5 prop and 3s LiPoly. Maybe I will have to play with that a bit.


I am still on my original 6V motor using 3S LiPo and 5x5. I ran the motor in underwater (in reverse) using 2 cells, and I put a drop of oil on both bushes once a month (it makes a difference!).

When I fly the Mugi, I don't fly it at full throttle continuously. For example, I might run it flat out for 1 minute before I get distracted by a passing seagull and 'say hello' for a while ;) , or I might practice some loops and rolls at part throttle. There is enough 'grunt' in this power system to fly at 60-75% throttle and still have an absolute ball!

I expect if I flew it flat out continuously, the motor would probably cook. The other thing which would help is the fact that the motor has constant air flow over it, so cooling is maximised.

I must admit, I have been waiting for the motor to die so I can try some other brands of Speed 400 to see how they compare. I have thought about a Zagi reverse timed Speed 400 or even something with ball bearings.

Does anyone have experience & recommendations regarding good or bad Speed 400's