K&B Sportster .65 (target drone engine)
08-19-2013, 04:30 PM
#51
Thanks for the info 1QwkSport2.5r
I would think that data should hold up for either drone engines or sport, since the only difference was a crappy carb, or at least I think that was the only difference.
Ken
I would think that data should hold up for either drone engines or sport, since the only difference was a crappy carb, or at least I think that was the only difference.
Ken
08-19-2013, 04:50 PM
#52
Thread Starter
Yes, you would be correct. I may modify one of the crappy carbs as an experiment to see if a little more airflow translates to more power from one of these guys. I do think the Sportsters get a bad rap like the Foxes do because of the long break-in, but they are such sweet running engines. Screamers they aren't, but they hand start so easy and idle lower than any engine I own. They do make a big mess though...
08-19-2013, 06:34 PM
#53
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Join Date: Jul 2012
Location: Buffalo, MN
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Cool,
you are still testing this engine
you don't flip start it by hand do you?
open exhaust?
you took the muffler off?
that was only good for 500 rpm?
Was it LOUD???
you did not try the wood 12 X 5 prop that came with the engine?
I plan to remove the carb and replace with a .65 spray bar and needle valve in the carb mounting holes
using a stretch tubing type bladder
for control line
Red line for this engine is 12,500 rpm from the spec sheet I sourced on line.
I would like to prop it to get 12,000 in the air
not sure about running a muffler
I don't have to
and lighter is better
but how loud are we talking here?
Thanks
Buzz
you are still testing this engine
you don't flip start it by hand do you?
open exhaust?
you took the muffler off?
that was only good for 500 rpm?
Was it LOUD???
you did not try the wood 12 X 5 prop that came with the engine?
I plan to remove the carb and replace with a .65 spray bar and needle valve in the carb mounting holes
using a stretch tubing type bladder
for control line
Red line for this engine is 12,500 rpm from the spec sheet I sourced on line.
I would like to prop it to get 12,000 in the air
not sure about running a muffler
I don't have to
and lighter is better
but how loud are we talking here?
Thanks
Buzz
I got my hands on some "civilian" Carburetors for my Sportsters and went on a prop testing spree.
74*F/64% humidity, 5%nitro 25% castor, McCoy MC59 plug, APC Props, factory sportster muffler.
11x8 11,700/2,400
11x9 11,600/2,280
12x6 11,550/2,300 (12,000 open exhaust)
12x7 11,100/2,100
13x6 11,100/1,950
13x7 10,600/1,950
13x8 9,900/1,800
74*F/64% humidity, 5%nitro 25% castor, McCoy MC59 plug, APC Props, factory sportster muffler.
11x8 11,700/2,400
11x9 11,600/2,280
12x6 11,550/2,300 (12,000 open exhaust)
12x7 11,100/2,100
13x6 11,100/1,950
13x7 10,600/1,950
13x8 9,900/1,800
08-19-2013, 07:11 PM
#54
Thread Starter
open exhaust?
you took the muffler off?
that was only good for 500 rpm?
Was it LOUD???
you took the muffler off?
that was only good for 500 rpm?
Was it LOUD???
you did not try the wood 12 X 5 prop that came with the engine?
I plan to remove the carb and replace with a .65 spray bar and needle valve in the carb mounting holes
using a stretch tubing type bladder
for control line
Red line for this engine is 12,500 rpm from the spec sheet I sourced on line.
I would like to prop it to get 12,000 in the air
not sure about running a muffler
I don't have to
and lighter is better
but how loud are we talking here?
Thanks
Buzz
Last edited by 1QwkSport2.5r; 08-19-2013 at 07:13 PM.
08-20-2013, 03:00 AM
#56
Thread Starter
08-20-2013, 05:43 PM
#57
Hey you know if you place a .65 Sportster next to the baby and take a picture, it belongs in the thread
Just saying
Ken
08-20-2013, 07:20 PM
#58
Thread Starter
I would at some point really like to put this pair of .65's on something. Whether it flies or floats, I don't care. I may end up flying the Mig-27 with my ST S90.
02-06-2016, 01:51 PM
#61
Senior Member
Ifound this thread and take it up.
Ihave made a bid on ebay for two k&b .65 engine,and waiting if ieven bought another.
If i get engine it must drive in and test props and ihope that i can use ma12×8×3 prop or 12x6x3
Ihave made a bid on ebay for two k&b .65 engine,and waiting if ieven bought another.
If i get engine it must drive in and test props and ihope that i can use ma12×8×3 prop or 12x6x3
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doclov (10-20-2020)
02-06-2016, 02:36 PM
#62
Thread Starter
Test a few two blade props too - I'd be curious to see what a regular civilian .65 will do compared to me target drone versions.
02-07-2016, 05:14 AM
#64
Thread Starter
Look for a ":91" stamping cast into the backplate. As far as I know, all target drone engines have this designation with no other markings other than the K&B logo and "Made in USA" cast into the side. The Carburetors are often machined differently and my two drone engines had no pinch at all. All of my other sportster engines (the other three models) have a tight pinch at TDC. The lack of pinch may be specific to the drone engines since they weren't broken in prior, just fueled, fired, and launched. I've heard of "regular" .65s having a good pinch like my 28 and 45 have.
02-27-2016, 12:19 AM
#65
Senior Member
1hour runing in time.
China apc 13x6 maybe 3d prop,20%castor 10% nitro ,webra four stroke plug, -4°c
10300rpm
Engine is very high compression,hand flip clockwise only, it kick hands very hard.
China apc 13x6 maybe 3d prop,20%castor 10% nitro ,webra four stroke plug, -4°c
10300rpm
Engine is very high compression,hand flip clockwise only, it kick hands very hard.
02-27-2016, 06:02 AM
#66
Thread Starter
These engines do have a good piston seal after they bed in nicely - I backflip start mine most of the time. If the engine was pretty new and tight, you're still breaking in and loosening up. You should see around 11,000rpm or slightly better on a 13x6 APC. Depending on your elevation, you might make a little more power on 10% nitro fuel than I do with my engines using 5% nitro fuel. If it will hold a rich needle setting and throttle well, go fly it to finish breaking it in. They only get better with time.
02-27-2016, 07:32 AM
#67
Senior Member
Itry replaced saito to k&b ,engine must be totally breakin before that and iwill run it very hard on bench.
That safety needle is not good,if it is screwed the engine it vibrates and fuel line get airbubles,if it is out of engine it works,but if try adjust it airbubbles will come again.
This engine is with short bronze bush in crankcase.
Static thrust is very good with big prop.
That safety needle is not good,if it is screwed the engine it vibrates and fuel line get airbubles,if it is out of engine it works,but if try adjust it airbubbles will come again.
This engine is with short bronze bush in crankcase.
Static thrust is very good with big prop.
Last edited by särpet; 02-27-2016 at 07:41 AM.
02-27-2016, 01:43 PM
#69
[QUOTE=särpet;12182693...
That safety needle is not good,if it is screwed to the engine it vibrates and fuel line get air bubbles,if it is out of engine it works, but if try adjust it air bubbles will come again...
.[/QUOTE]
I am not sure with the carb you have, but I have several times taken a screw out of the carb side and screwed the needle valve assembly directly in to the carb body, taking the remote gadget out of the system.. No more bubbles. I learned long ago not to get my fingers in the prop. Good luck.
That safety needle is not good,if it is screwed to the engine it vibrates and fuel line get air bubbles,if it is out of engine it works, but if try adjust it air bubbles will come again...
.[/QUOTE]
I am not sure with the carb you have, but I have several times taken a screw out of the carb side and screwed the needle valve assembly directly in to the carb body, taking the remote gadget out of the system.. No more bubbles. I learned long ago not to get my fingers in the prop. Good luck.
02-27-2016, 04:16 PM
#70
Thread Starter
I have two Jett engines that use remote needle valves and never have bubbles in the fuel line between the remote needle and the carburetor. The trick is if you encounter bubbles between the needle valve and carb is to isolate the needle valve - remove it from the engine and run the engine again. If no bubbles, then you have a vibration issue causing the nucleation effect. Balancing the prop better should help, however mounting the needle valve on a firewall or anywhere else that's still inline with the carburetor should help and minimize bubbling fuel.
02-28-2016, 10:36 AM
#71
Senior Member
Over hour very hard testing.
10% nitro -1.5°c
China apc 13x6, webra four stroke plug 10500rpm
Fox long with idlebar 10400rpm
J'en medium 10400rpm
Apc 12x6 ,webra fs plug 12200rpm
MA 12x6x3 ,webra fs 10300rpm
MA 12x8x3,webra fs 9600rpm
Engine works better with J'en plug, itake head of and took it to a lathe,now ican use normal lenght medium plugs.
Tomorrow more testing.
10% nitro -1.5°c
China apc 13x6, webra four stroke plug 10500rpm
Fox long with idlebar 10400rpm
J'en medium 10400rpm
Apc 12x6 ,webra fs plug 12200rpm
MA 12x6x3 ,webra fs 10300rpm
MA 12x8x3,webra fs 9600rpm
Engine works better with J'en plug, itake head of and took it to a lathe,now ican use normal lenght medium plugs.
Tomorrow more testing.
Last edited by särpet; 02-28-2016 at 10:43 AM.
02-28-2016, 11:46 AM
#72
Thread Starter
Your "Webra" 4-stroke plug looks identical to a Fox Miracle plug.
Nice work on the head. If those shorter plugs are all you have access to, by all means use it.
Nice work on the head. If those shorter plugs are all you have access to, by all means use it.
02-28-2016, 07:56 PM
#75
Senior Member
