A COX .098?
12-27-2003, 12:32 PM
#1
A COX .098?
Hey guys, a picture of what my Dad has been playing with in the shop. He brought it to the Winston Salem swap meet and I forgot to bring it to the last 1/2A meet at Johnson County. He says it does run and has the power of a good Tee Dee .020!! Hey Tim, got one of these?
Bob Harris
Early RC Models
www.earlyrcmodels.com
Bob Harris
Early RC Models
www.earlyrcmodels.com
12-27-2003, 02:00 PM
#2
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RE: A COX .098?
Bob,
Hey I just got back from hanging out with your Dad at his flying field and he didn't say anything about it! It looks like one of AJC's twins just made alittle different. Only the power of an .020...what...?
P.S.
I got your engines and will get right on them
Later,
Tim
www.hypercoloranodizing.com
Hey I just got back from hanging out with your Dad at his flying field and he didn't say anything about it! It looks like one of AJC's twins just made alittle different. Only the power of an .020...what...?
P.S.
I got your engines and will get right on them
Later,
Tim
www.hypercoloranodizing.com
12-27-2003, 11:02 PM
#4
RE: A COX .098?
Yep, he said the power did not impress him much. Ajcoholic how is your's timed? Both cylinder firing at the same time, opposed? He gave it to me to play with but I have not had time to give her a run. Tim, I found another Pee Wee .020 I forgot to give to Dad. I will see if i can get it off to you this week.
Thanks,
Bob Harris
Early RC Models
www.earlyrcmodels.com
Thanks,
Bob Harris
Early RC Models
www.earlyrcmodels.com
12-28-2003, 05:51 AM
#6
RE: A COX .098?
I am not sure I will need to check with him or run it myself. He just said that with the drag caused by the gearing it did not produce much thrust.
Bob Harris
Early RC Models
www.earlyrcmodels.com
Bob Harris
Early RC Models
www.earlyrcmodels.com
12-28-2003, 06:08 AM
#7
RE: A COX .098?
OK, thanks. I was planning on making a smaller version using 2 PeeWees, but if it wont have as much power as an .049 then there isn't much point.
AJC, how was your twin for power?
AJC, how was your twin for power?
12-28-2003, 10:20 AM
#8
My Feedback: (10)
RE: A COX .098?
Bipe,
ANY two engines geard to drive one shaft will have theoretically less power due to the mechanical losses of the gear train. However, since they can be geared down to drive a larger prop at a slower RPM (which can indeed give a lot more thrust but at a slower velocity) a twin like that is good for a slow, draggy model. Mine can easily swing a 9-6 prop or a 10-4 at about 8 or 9 thousand rpm's. You aint gonna get that thrust with two 049s turning 12 or 13 thousand rpm on 6-3 props.
Its all give and take, and how you gear them, what prop you run, etc. and what plane it goes in.
AJC
ANY two engines geard to drive one shaft will have theoretically less power due to the mechanical losses of the gear train. However, since they can be geared down to drive a larger prop at a slower RPM (which can indeed give a lot more thrust but at a slower velocity) a twin like that is good for a slow, draggy model. Mine can easily swing a 9-6 prop or a 10-4 at about 8 or 9 thousand rpm's. You aint gonna get that thrust with two 049s turning 12 or 13 thousand rpm on 6-3 props.
Its all give and take, and how you gear them, what prop you run, etc. and what plane it goes in.
AJC
12-28-2003, 07:06 PM
#9
RE: A COX .098?
Sorry, nomenclature problem. I want to have more torque than a .049, not necessarily more HP. Two engines on a gearbox wont put out twice as much HP as one did individually, but if they are geared down they will put out more torque. I was just wondering why the above setup would have so much mechanical loss that it would put out less with 2 engines combined than each did individually. Maybe the gear mesh is too tight.
12-28-2003, 07:48 PM
#10
My Feedback: (10)
RE: A COX .098?
I will tell you, any time I ran one of my geared twin 049's they put out a wee bit more power than an 020.... 
Like I said I would compare it to a .10 size, and I wouldnt swing a 9" or 10" prop on my os .10 fp, I was running a 7-4.
There was a twin 020 commercially made about 25 years ago, it was a nice little engine called the "tee pee twin" and they were cute as heck, and are now a prized collectors item.
AJC
Like I said I would compare it to a .10 size, and I wouldnt swing a 9" or 10" prop on my os .10 fp, I was running a 7-4.
There was a twin 020 commercially made about 25 years ago, it was a nice little engine called the "tee pee twin" and they were cute as heck, and are now a prized collectors item.
AJC
12-28-2003, 09:30 PM
#11
RE: A COX .098?
Well maybe a bit more than a .020. Dad has been keeping up with the post. He said that the .049s used were not new and he really did not play with it much. Hey Tim, got any mods to get this thing to turn about 10,000 rpms?
Bob Harris
Early RC Models
www.earlyrcmodels.com
Bob Harris
Early RC Models
www.earlyrcmodels.com
12-28-2003, 10:03 PM
#12
My Feedback: (10)
RE: A COX .098?
The rpm of the prop shaft will be, of course, dependant upon the max rpm of the engines used (whether they are single, or dual bypass cylinders, and how good they are in condition) and the gear ratio of the gears. And of course the prop size... LOTS of variables...
AJC
AJC
