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

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...

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

Most of the time, I wet prime it and backflip start it. I do not like using electric starters on bushing engines.
I ran open exhaust on only one prop as noted in my previous post. Only ran it that way as a test to see how much the stock muffler choked it down. Not much I noted. Loud? Incredibly. Also incredibly messy. Oil ALL over my test stand.
No. I do not use wood props.
Good luck. The carb is held in by a single drawbar between the carb orifice and the cylinder. If you plan to run it as a CL engine, find a NV and Venturi that fits. I'm unaware of any that fit, this may need to be custom made.
The engine definitely likes to be loaded down. It will turn faster than 12,800 (the actual top rpm listed by Mecoa for the bronze bushed version) just fine, but it may not be happy. I didn't run mine that fast until I got 3 gallons through it where it was actually breaking in. Mine ran hot before that 3 gallon mark even at 10,000rpm. If it were me, and I want my engines to last, I'd be propping it heavy to turn around 10,500-11,000 on the ground MAX. You're just going to wear it out quickly if you prop it to run faster. This engine will turn a 14x6, but is happier turning a 13x6-13x8.
I had ear protection on for my 12x6 open face run and it still gave me a headache. It's LOUD.

Did you ever get your drone built and flyable?

My wife and I welcomed our first baby to the world in March... So no I haven't. :D Probably next year. I have my little Norvel 1/2a trainer pretty much RTF with an OS FP .10 though. I gotta learn to fly first. LoL.

Congratulations on the addition :D

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

LOL! I have two Sportsters, one in each hand! I'll clean up my slimy runner and see if I can get him to hold both of them... He's already sorta famous on Facebook thanks to my wife and her friends. The kid isn't even 6mos old and has a fan club of at least 50 people...

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.

Up.

??

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

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.

Where to distinguish between normal and target drone engine?
What is main difference?
Both engines are not used and without box or papers.

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.

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.

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.

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.

Yes, static thrust is very good indeed! ;). About 9 pounds/4 kilograms at 10k rpm.

[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.

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.

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.

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.

Idont know what plug is in picture,it not glow,but dimensions are same than webra.

Yeah, bottom two plugs in picture are Fox plugs. Top one I'm not sure. Definitely don't use those 4-stroke plugs in the modified head now.

Top plug is J'jen medium.
http://www.justengines.co.uk/acatalog/Glow_Plugs.html