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Sep 06, 2019, 09:13 AM
Registered User
Thread OP
Discussion

.15 (2,5cc) car engine for ducted fan?


Hello,

I don't know much about cox engines. I would like to know if an OS max 10 would give about the same power as a cox 15?


From what I understand the cox 15 is 1,5cc and the OS 10 is about 1,7- 1,8cc.
It's going to be used in a ducted fan deltawing which require a cox 15 or similar, maybe the OS engine can't rev that high?


Edit: Found an article of the cox 15. Itís 2,5cc. Would an os 15/20 be similar?
Last edited by andriksen; Nov 03, 2019 at 02:24 PM.
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Sep 06, 2019, 09:33 AM
Master re-kitter
SRQFlyer's Avatar

Cox 15


A Cox .15 is .15 cu. in. or 2.5cc. It will run circles around an OS 10 and weighs less also. The cox hasn't been made for years, so it may be hard to find a good one. I'm not sure if Cox International (in Canada) has "new" ones for sale, but worth a look.
JIm
Sep 06, 2019, 09:45 AM
Registered User
surfer_kris's Avatar
Are we talking about the TD or the Conquest engines?

The Cox Conquest is a great engine, stronger than most modern .15 engines and the rear exhaust would be well suited in a DF. They are not made anymore though and the conrod is a little weak on the earlier models. The best thing would be the very rare ABC version.

A modern car engine can easily be converted though and would beat the Cox Conquest at high rpm applications...

As an example the Picco .12 is a great engine. It has a rear exhaust and as an airplane engine it is stronger than most .15 engines and the weigh is similar. It will easily spin an APC 7x4 prop at around 22000rpm.
Last edited by surfer_kris; Sep 06, 2019 at 09:51 AM.
Sep 06, 2019, 09:57 AM
Registered User
Thread OP
Beautiful engine surfer_kris! Had to check, it's actualy a cox 15 special.

I just remembered that I have a 3,5cc K/B boat engine with rear exhaust laying around.. might be to much power/weight
Sep 06, 2019, 10:19 AM
Dieselized User
gkamysz's Avatar
Which fan is this for?
Sep 06, 2019, 01:08 PM
Registered User
Thread OP
It's kinda homemade I guess.. https://outerzone.co.uk/plan_details.asp?ID=9155

I have not built the plane yet.
Sep 06, 2019, 01:41 PM
///////
coriolan's Avatar
The Cox TD .15 used by C.W. Peake in his fan had a lot more rpm and power than the OS max-10!
http://sceptreflight.com/Model%20Eng...20Mk%20II.html
http://sceptreflight.com/Model%20Eng...0Max%2010.html
https://outerzone.co.uk/download_fil...55_article.pdf
The suggestion made by surfer_kris would gives you a better chance of success!
Sep 06, 2019, 05:29 PM
Registered User
Not to mention that the Cox .,15 special has value as a collectible, if in good shape. If put up for auction, you may be well on your way to buying something more suitable for your application.
Nov 03, 2019, 02:21 PM
Registered User
Thread OP
Ok, little update here. I've been searching the web since last time I wrote in this thread and it's hard to find something that is for sale in my country. I found an OS MAX 15cv-x car engine. What do you think about this one guys? The fan in the plane is a pusher type.

It's heavier than the "Special" engine but, im hoping to compensate on the radio equipment.
Nov 03, 2019, 02:51 PM
///////
coriolan's Avatar

Lucky you!


Quote:
..... hard to find something that is for sale in my country.
Where would that be? In most places its virtually impossible to escape consumerism for things we don't want or need
Nov 03, 2019, 03:36 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
Quote:
Originally Posted by andriksen
Ok, little update here. I've been searching the web since last time I wrote in this thread and it's hard to find something that is for sale in my country. I found an OS MAX 15cv-x car engine. What do you think about this one guys? The fan in the plane is a pusher type.

It's heavier than the "Special" engine but, im hoping to compensate on the radio equipment.
Those engines are poor performers. Not much power. Get a Novarossi 2.5SC instead.
Nov 03, 2019, 03:40 PM
Registered User
surfer_kris's Avatar
Quote:
Originally Posted by andriksen
I found an OS MAX 15cv-x car engine. What do you think about this one guys?
That should be a nice and strong engine. The X notation usually stands for a starter (?), you might want to remove that in order to save weight. Or perhaps you want to keep it for the ducted fan aplication.

I have "converted" an OS .12CV to airplane use and it runs very well (the power matches other .15 engines):
OS .12 CV converted for airplane (0 min 38 sec)
Nov 03, 2019, 08:00 PM
GloBroz PowerLab
1QwkSport2.5r's Avatar
The CV engines with square heat sinks are toads. Not worth the time to convert. That’s where my comments from my previous post come in.
Nov 04, 2019, 01:43 AM
Registered User
surfer_kris's Avatar
Well, compared to a Novarossi they might not be very strong but they are stronger than the other airplane engines from OS (FP and LA). The OS .15CVA was based on the car engines and that was their best .15 airplane offering at the time.

The newer car engines from OS are better, but they are also much heavier.
Nov 04, 2019, 02:19 AM
Registered User
Reginald's Avatar
Quote:
Originally Posted by coriolan
Where would that be? In most places its virtually impossible to escape consumerism for things we don't want or need
Could be abba region...


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