props.

| Thinking on building a 42'' span trainer that calls for a Speed 400 and | 2.33/1 gearbox driving a 9x5 slimprop, as I have decent 9x6 nylons and a | 8x6 Masterprop spare can I use one of these and what effect will it have | compared to the 9x5?, will a slightly higher pitch cause the motor | problems? (Graupner 400 motor and gearbox),

The 9x6 will cause slightly higher power consumption at the same throttle level, and therefore slightly higher heat. It might give you slightly better performance.

The 8x6 could go either way vs. the 9x5. If you had a 3D plane it probably wouldn't work as well, but a trainer rarely does 3D, so ...

It's hard to be more specific without knowing the specifics about your entire power system and putting them into Motocalc or something similar. But if 9x5 works well, the other two props will probably work OK as well.

And really, props like that are cheap, so try what you've got.

for all your speed motor gears and props issues.

The best ever on a 2.33 400 (6v) is a APC E 7x5 prop and 3s LIPO.

APC 8x6 is not bad on 8 round cells. APC 9x6 loads it up too much..its no better and the current is higher and the motor is hotter.

I had a master airscrew 8x6. In fact I still have it. I now use it to pick my nose.

It proved unable to actually propel an aircraft.

The message from "Doug McLaren" contains these words:

Hi Doug, the plans recommend a 9x5 slimprop and Speed 400 which I have a couple as last night I bought a new Graupner 2:33/1 gearbox and Graupner Speed 400 motor all still in the original packaging for about $17 on eBay which is exactly what is recommended so if it would be better to buy the correct prop then no problem, not bought or even decided what electronics kit I will install as yet as I have only just decided to build a decent sized trainer to get into the air with. A lot of newbies think twice I think about building their own airframes but afte 30 years of building scale sailing ship models working from plans anything up to 300 years old and so on that sort of stuff is no mystery, it is the electronics and power trains I need to learn about as my ship models all relied on wind.

But if 9x5 works well, the other two props will probably

Just thought it a waste of money buying a prop if I have one in my box, while on the subject I have aquired a graupner 4.7/4.7 speed prop from somewhere described as a CAM(?) prop and wondered what it is for or what use I can put it to,

regards, Terry

Those props are used on very high rpm motors such as pylon racers and other high speed aircraft. I use the graupner cam props in the 5.25 x 5.25 range on my VIP electric pylon racer which turns in excess of

CAM simply means computer aided manufacturing.

I buy quite a few of these at $5.00 each. Usually break one every couple flights since I have to belly land and these little guys don't slow down very well. Seems as though the prop ends up stopping vertical more than horizontal. :-( . Ken

The message from Ken Day contains these words:

Thanks Ken, just wondered if it was of any use so will leave it in the box for now, it came with a Race 480 and prop adaptor as I recall bought off eBay still in original packing for about $7 the lot so I got my monies worth I think, you see quite a few sets like that bought for some project or other that never took shape then it all ends up on eBay,

regards, Terry

speed 400 direct drive on 8 cells..or 3s LIPO if you want a brief experience.

At what RPM?

Dan

Hmm.

That would probably depend on the boger % mk

"MJKolodziej" wrote

I don't know about the RPM's, but I would estimate that cruise would be getting 6.5 boogers per minute.

The message from "Morgans" contains these words:

Its when the buggers go into reverse pitch it makes your eyes water................

regards, Terry