can anyone give me an idea what would be a good strating prop for a Mag. 180 4s. The chart that I have (not the manual) shows a 160 then the next step is 240 engine. Hobby People show a APC 16/8 does that sound about right?

G'Morning, Irish.

Big!!!!

I have an 18-10 for my OS 1.60 two stroke.. that prop you mentioned seems a tad small for that big torque maker.

CGr.

Good morning CGR

I don't have the manual so I wasn't sure what prop to use. But I am like you, I thought it was on the small side myself. Did you decide to go to the Toledo Show.

Hi.

I can't head over this year. We have just to much going on right now at work. I will probably head down to Herndon, VA later on this week to relieve the guys that are down there now. This will probably go on for the next month or so, then we head down to Florida to continue with actual flight tests. T'is a busy time for us right now.. goes in dribs and drabs.. busy then nothing, then busy... and on and on.

Meanwhile, I have a 16-8 APC on my OS 1.20 AX and it turns at about 9,000 RPM or so and does well. I also have a 15-10 for that engine which also does great..

For that 180 4S, though, I would imagine a larger diameter.. perhaps on the 18" size.. pitch.. well, that torque generator should be able to handle at least an 8 pitch.

CGr.

What's this work thing. I thought you were retired!!!!!

Well, I am.. sort of. I retired from the CG in 1997 and moved on over to the FAA as a contractor... sort of double dipping.. Pays for the new ARF's!!! Seems that every time RCKen or Minnflyer does a review, I just gotta have that plane!!!

CGr.

Hey CG
Here is something for you

[size=3]Only special minds can read this [/size]

fi yuo cna raed tihs, yuo hvae a sgtrane mnid too

Cna yuo raed tihs? Olny 55 plepoe out of 100 can.

i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt!

Ha... that's pretty slick. I read through it as though it was all correct!! Neat!! Where did you get that?

CGr.

AH!!! my wife sent it to me. Must be something wrong with me, I didn't have any problems reading it either Hummmmm tinhk I wlil mkae it OK

Yse, yuo wlil proablaly do ok..

Educators would have a ball with that!!! I have a friend out in Oregon that is a teacher. I sent it to her.. expect an intesting reply!!!

Ha..

I've got a meeting to head to..

later Irish.

My Saito 1.80 likes a 18X6 or a 17x8 APC.

David

Thank Daveopam

Guess I will head out to the LHS. Well in my case not to local.

The leaflet that came with my Magnum 180 recommends a 16x8 for break-in. Then 16 x6 to 16 x 10 and 18 x 4.5 to 18 x 6.
If you would like me to send you a copy of these instructions please send pm

Actually the OS 1.60 2C is more powerful than the Mag 1.80 4C, so the Magnum does use a proportionately smaller prop.

16x8 is right in the middle of it's operating range.

I have a 18x6 on mine, for my Giant UCD.

WOW!!! Why is the 160 more powerful?

Well time for the Slim Fast be back shortly. Maybe I should grill it this time.

The 2C 1.60 "hits" on every revolution while the Mag 1.80 on every other.

There is only a minor difference in the displacement, so the 2C 1.60 outpowers the Mag 1.80 4C.

If anything you would need to move into the 2.0+ CU 4C range to get the equivalent output to the O.S. 1.60 2C.

Recommended prop sizes and bHP ratings ( yes we all know that they ARE inflated to head off others chiming in here ) also bear this out.



Normally when you compare a 2C engine to a 4C one, you need to go a couple of sizes up on the 4C engine to get the equivalent output power.

The 4C engine is however lighter on fuel usage...

In reality the OS 1.60 2c has comaprable power to a 45-50 cc gas engine. The big problems with the 2c
engines is that there power is made in the higher RPM ranges with where a 4stroke and gasser make there
power in midrange.

I use an 18.1 x 10 on my os 1.60 and I have the power to pull a 11lb plane vertical at 1/2 throttle.
I use a tuned pipe to get the engine to make power where it is needed around 1/2 - 3/4 throttle.

See!! Opjose. This is what happens when you don't read all the words. I was thinking 160 4s not a 2stoke.

Deleted: Duplicate post

Heh... I believe that O.S. does not manufacture a 4C 1.60.

Where would you put a BGX-1 when comparing it against a gas engine?

On the ground next to the 3 gallons of nitro it takes to run it for 10 minutes.

A friend of mine has used the OS 1.60 in an 85inch yak as an experiment and found that
the plane came in at just under 13lb and flew aerobatics reasonably well. He also commented
that the plane with a 50cc flew 3d excellent which is why I said comaparable power.

I have never seen the 3500 in a plane so I can't comment. but I would have to say if you
go by the specs of a gas engine compared to this it should have excellent power and save weight.
But the loss of overall weight from the engine will be offset by the 50OZ fuel tank. Unless you
can get a midair refueler.

Wow that bad!?!!!!!

I had imagined them to be in the 2.4oz/min at WOT consumption range.

It sounds like I'm optimistic.