r175 slow speed question

[mobile_bob]

my latest project (at about an hour ever day or so) is slowly coming together...

my question is this, (because i have not worked with the 175 changfa)

how slow will they run reliably?

mine is rated at 2600rpm

ideally i would like to run at 1400rpm slow speed operation and ~2000rpm for high  speed operation

the 2000rpm doesn't concern me, i am pretty sure it will do that no problem
its the 1400rpm that concerns me.

anyone have any experience with these engine's at around ~1400rpm?

btw, the load at that speed will be approx 2kwatts max, likely about 1.5kwatt continuous

thoughts?
bob g

[veggie]

Hi Bob,

My experience with my R175 is that they are quite comfortable at 1400 rpm.
You should be able to generator 1.5kw of power based on your elevation.
I am at 3300 ft. ASL so I have to derate my expectations by approx. 10%.

Attached is a power chart I generated for this engine allowing for various variables.
I assume that you are not above 1000 ft. ASL so this chart should work for your application.

Model                        : R175
Design Altitude           : 1000 ft.
Altitude correction Factor  : .97
Factory Rated BHP      : 6.6
RPM at rated BHP       : 2600
Estimated Droop        : 10%
Estimated Min rpm      : 1000

When I key in the above data, the performance chart below is generated.
I dare say that you would have to run the engine at 1800 rpm to generate 2kw of electrical power.
But 1.5 kw at 1400 rpm is quite possible.
(Assuming 2HP per kw)

Looking forward to the pics  
cheers,
veggie

[glort]

I have had a 165 Driving an induction motor running for many hours and never had any problems with it.  Being a fixed pulley, this is about the speed I have to run it to suit the ( oversize) induction motor I have. Mine will develop  a tad over 2 KW of generated power at that speed even though the engine itself is only rated to 3.3 Kw.
The horizontals seem to be very gutsy little engines.

[Henry W]

When the oil is hot what will the oil pressure be at 1400 rpm's? It most likely will have enough oil pressure but I feel this would be good info for us to know. Is there a place to hook up a pressure gauge and get pressure readings at rpm ranges from 1000 - 2600?

Chances are the R175 will not be subjected to enough stress to be concerned about oil pressure.  I know the smaller R165 is splashed lubed only and it does fine.

Henry