rustypep

My Feedback: (6)

I have a little over 2 1/2 gallons on my SK 50 and it is really shining. I put seven more flights on it on Saturday and no dead sticks and the idle has a real nice sound with the stock muffler still. Almost sounds like a chain saw at idle. I have a long weekend coming up and I think I will experiment with a few props that I picked up that I have been meaning to try. Temp was around 75 and I am at roughly 425 ft. ASL. I don't remember the exact peak number but it was over 11,900. I obviously backed it off from that for flight. I am running 15% Omega I am now hovering at about 60% on the throttle and I can take off and go vertical on a full tank now straight into a hover after about a 30-40 foot rollout. It still doesn't have unlimited vertical but for a 5 lb 4 oz Ultra Stick (dry) I am real happy. One of my friends commented that he isn't getting anywhere near that power with his Supertiger 51. I did buy a new carb so I have some spare parts. The HS needle valve clip broke on mine and I got a new one of those too. I just ordered another one so I can get it broken in and have a backup. I also ordered some lighter servos so I can shed some more weight.

I wonder how this thing would run on a regulator? It would be nice to move the tank back to the CG.

rustypep

My Feedback: (6)

SK 50 on 15% Omega. I got a reliable figure of 11,960 peak on the 12x5 at about 425 ft asl with a temp of 86 degrees with about 40% relative humidity. No wind either. It crossed 12,000 briefly but didn't hold that day.

Turk1

My oldest SK 50 surviving from several crashes and bearing change.(Only one shim on head for sealing function)


Temp 91-95 F Humidity high,about 100-200 meters above of sea level.
Fuel industrial methanol, 20 % full castor, self mix fuel,no nitro. OS A 3 plug.Prop 12-5 APC with spinner and DuBro exhaust deflector.
12120 RPM highest. After installing BruLine type air filter it fell 11900 RPM max.

Tach is Hobbico.

rustypep

My Feedback: (6)

I guess I need to try that A3 plug. You are basically getting the same numbers as me but on FAI fuel versus the 15% I am running plus you are using more castor so that is a really impressive figure. I forgot to mention I am running a full length Dubro exhaust deflector too. The most I have seen on a good day is about 12,200 but it has never held at that figure especially with the deflector in the heat. I did order a new carb so maybe I will see if that makes any difference too. I am real happy with the performance on my ultra stick 40. It is also very fuel efficient which I like as well.

Turk1

Hi Rusty,Im so happy with OS A3 plug.Neither with #8 nor brand new Enya 3 .My so easy starting engine gives me trouble with Enya resisting to start.So much that I gave up to test for RPM s with Enya.Also you can check with your headshims too.I think worth to try on less shims.(Also you can have a try to drill those fuel inlet holes on spraybar to have bigger 2 holes on old carb..I did this on winter conditions)

HAIDAR

HI DEAR MODELRES
I INTEND TO BUY SK50 & SK90 ENGINES. WOULD YOU PLEASE TELL ME
HOW WELLDO THEY WORK AND WHICH SIZE OF SK ENGINES ARE BETER
(40 THROUGH 1.30) I MEAN WHICH ONE IS MORE POPULAR & WHICH ONE
WORK WITHOUT PROBLEM ( ZERO NITRO FUEL).
THANKS.

prgonzalez

I have two SK-90 and one SK-50. I am happy with these engines and will continue using them for new models whenever time to purchasing comes.

I have use 5% and 10% nitro with them without any problems in over 60 x 11 minutes flights.

HAIDAR

DEAR prgonzalez
   DO YOU KNOW HIMODEL (CHINSE E SHOP)

prgonzalez

I do not know HIMODELS. I have ordered from Hobby King before but I am not sure if they carry SK engines.

Abrams

My Feedback: (2)

This thread is a couple years old, but hopefully someone will see this.

I have a Seagull Edge 540 that is a .46 to .60 size plane. It has a tired Evolution .46 engine in it that I salvaged from a PTS P51. It doesn't quite have enough power to hover. I also have a Kangke Cap232 with a Brison 2.4. I was on their site poking around and saw the nitro engines. I was toying with the idea of buying a .60 Evolution, but the SK look like a possibility.

I see much on this thread about the .50 and the .90. I don't see anything on the .70. Anyone have any experience with this engine? I think the .90 would be a little big.

rebanks

How's it going everyone?

Been working on my new hobby website at:

http://www.craftandhobbysupply.com

It's still a work in progress but I feel it's reached the point to go live.

Several products including ARF planes, SK and JBA engines are populated and ready to go!

tonywayne

Received my first SK engine by mail today "SK 50". Mounted it on test stand with a MA S-2 series 12X5 prop. Did a typical ABC break in "rich and lean cycles". After about 6 tanks it is turning 12200 WOT "set rich" and idles at 2200 with very good transition and reliable idle. This is with an old used glow plug thats been rolling around in my field box for years i might add.
I am extremely impressed with the smoothness and quality of this engine for a price of 79$. It performs just as good or better than brands twice the $. It will be going in a Hobby Lobby Telesport.

buzzard bait

I often see recommendations about 4 strokes, and in this case some 2 strokes, to choose a prop that limits the rpm on the ground so it won't lean out in the air.

What puzzles me is people seem to think it doesn't matter whether the low rpm is achieved by large diameter/low pitch or small diameter/high pitch, and long as the rpm stays below some figure, like 10,000 rpm for example.

But it must matter, right? Because even if an 11x8 prop had the same load as a 12x6, for example, the 11x8 would rev up higher in the air. On the ground, you'd think everything was fine if the 11x8 didn't rev too high, but then you put it on a clean airframe and now there's a big difference.

Jim

Abrams

My Feedback: (2)

The exact same thing goes for props on boats. At OMC we had barges on the side of the building is a bay off of Lake Michigan. When an engine is trying to push a building, there is a lot more resistance than pushing a boat of any size. To simulate a true running condition, they would cut down the prop until the engine would get up to normal operating RPM.

I haven't heard a good formula for cutting down a prop.