280 vs. 300 motors

[t-turley]

OK, I'm a wee bit confused about this 280-300 thing. For 5-6 years I have flown geared 280BBs; first the GP28BB from Kyosho, and then the Permax 280BB. (Both of these motors, by the way, look identical except for the label.) These motors are the same diameter as a Speed 300, about 1/4" longer, and handle a whole LOT more power. So when you folks talk about a 280-powered plane, are you talking about a Speed 280, or a "280 can" (Speed 300) size plane?
BTW, I can personally vouch that a GP28BB/Permax 280BB will haul a 21 ounce plane *with authority*.

Tony Turley

[jimwalker]

I'm sure you are correct about those 2 motors you are referring to being very powerful. To answer your question, I don't think there is any specific standard for "speed 280" motors except maybe, as you stated, the can size and then even less so, maybe overall weight. I'm sure if you weighed a mabuchi 280 (the cheapest 280 I've seen) and your motors, yours would weigh considerably more. Also I'm sure they cost quite a bit more than the $7 a mabuchi costs. If you know basic electric motor design, then you know that performance is a function of materials and workmanship. Better magnets, number of winds, commutator and brush material, bearings, and finally quality construction determine how many watts a motor will give you. A simple way to say it is from a sign over the parts counter at the local electric car track where I used to race. It said, "Speed is money, how fast do you want to go?" To back up these statements let me tell you about my experience with a "speed 280" plane. After assembling my plane, I was very disappointed in its performance. In fact I could barely keep it aloft. I finally decided that I needed more power because the plane was under weight compared to the spec's on the box it came in. I purchased a "speed 300" motor online and installed it in place of the mabuchi 280. It fit perfectly in my gearbox and the pinion pressed right on the output shaft. The plane is now a strong performer! It loops from level flight at 2/3 throttle and will climb out of sight on 1/2 power. The difference in motors? The 300 motor weighs about half again as much. I assume this is because of the winding, bearings, brushes and magnets. All other physical dimensions were the same. It was obvious that this motor was a finely made German product. Lastly this motor costs 3 times as much or about $21. I hope this answers your question.....

Happy flying!

[t-turley]

Originally posted by jimwalker:
<STRONG>Lastly this motor costs 3 times as much or about $21. I hope this answers your question.....

Happy flying!</STRONG>

Thanks Jim. That is pretty much what I figured. You are right about the "Black" 280BB motors - the GP28BB ran for about $35, and the Permax 280BB now goes for around $30. Not cheap, but the performance is incredible. For comparison, I once had a generic "280/300" in a gearbox. The motor was rated for 5 cells, but I used 6. I literally vaporized the brushes on the second flight. :)

Tony Turley

[ 05-29-2001: Message edited by: t-turley ]

[frankenfoamy]

The motor was rated for 5 cells, but I used 6. I literally vaporized the brushes on the second flight.

you may have had a 4.8 volt motor

[jberg]

Hi,

I think there is a little confusion about 280's. There are more or less three types of motors:

- the original relatively cheap Graupner Speed 280 can motor (also available from other suppliers). This has carbon "hammer" brushes (the brushes are fixed with a short, spring-loaded lever), a plastic endbell and no air holes. It works best with 7-8 cells of 350 NiCd or (better) 700 NiMH (Sanyo Twicell!), a gearbox of 4:1 or 5:1 and an APC Slow Prop of 9x6 or 10x4,7. It will drain about 2,5-3A at full throttle and works nicely with slower models up to 300-350g and a relaxed flight attitude. Some people treat this motor with a 3:1 gear and higher current, but the drive does not like it. Don't mix it up with similar looking, very cheap Igarashi motors which don't have carbon brushes and wear out *very* quickly!

- the Speed 280BB kind of motors. These are expensive, have an endbell with open carbon brushes which are guided and spring-loaded linearly in a metal slot (sorry, I am no native speaker of English, don't know how to describe it better). These drives are much more powerful, have better efficiency and take more current (about 5-6A) from 7-8 cells. They work well with 5:1 gear and 8x6 to 9x6 props. They are good for indoor and small, light outdoor aerobatics, like the Depron planes that are common in Germany.
Don't mix up these motors with the standard Speed 280, they are much more similar to the Speed 300, but of higher quality.

- the Graupner Speed 300 and similar from other suppliers. This can motor costs a little more than the Speed 280, has a metal endbell and looks like a smaller Speed 400. It has almost the same power as a moderately working Speed 400 and takes the most current of all motors mentioned here. This motor is hot and has the highest kv value! It likes higher gear ratios about 6:1 and is also good for aerobatics. Use max. 6 cells or the current will go high. Or use it for very small ducted fan units because it will run at very high rpm if used with more cells.

[Achim Stegmeier]

Just my additional 0.02:

There are at least 3 flavours of the cheap 280s:

-The Graupner Speed280 with carbon brushes made by Mabuchi
-The Robbe 280 with carbon brushes made by some other Company
-The Igarashi 280 presumably with metal brushes

BTW, the 280BB is made by Sagami.

Achim

[t-turley]

Originally posted by Achim Stegmeier:
<STRONG>&lt;SNIP&gt;

BTW, the 280BB is made by Sagami.

Achim</STRONG>

Yep, so is the DM20BB, another motor that has piqued my interest.

Tony Turley

[groundloop]

Can any of you tell me where I can get these hot 280 motors?

[jimwalker]

Hobby Lobby, (listed in the vendor links), is where I got my speed 300 motor that really pepped up my slowflyer. They have a ball bearing version that will probably be equivalent to t-turley's screamin 280 motor.