Keil Kraft Super 60

[Ianb]

Hi,

I am scatch building a 3 channel Keil Kraft Super 60

Can some one please tell me the most suitable size engine to use 2 stroke or 4 stroke?

Thanks Ian

[Braddock, VC]

I'd try and get hold of a second hand OS 35 FP, or an enya 35 but ensure that it's the non bb engine and ensure that all the components are included eg silencer, silencer bolts, carb etc. I'd prefer the OS though.

Some folks use cooking 40s which have the benefit of a larger range of props, once again OS or enya plain bearing jobbies.

Any of these engines will run until the cows some home and, ok they're on the upper level of power for the model but they are so reliable and if you have to put noseweight in to get a good c of g what better way!

 

IMHO the ball raced schneurle port clones eg sc, asp and magnum are too powerful and should be avoided if at all possible, as should the 32s, 36s and 39s with ball races. Fine engines in all other respects though.

 

The plain bearing engines can be abused or misused and will come back for more in my experience.

[Ernie]

Hi Ian,

 

It's one of these questions that polarise opinion...

Personally, I'd go for a four stroke. They tend to be more reliable, if less powerful. They will swing a bigger prop than a two stroke, and are certainly quieter. And the noise is just sublime

There are not too many really small ones available The OS 30 springs to mind. They are more expensive than a 2 stroke, 'cos they're more complex

 

ernie

[Ernie]

Hi again Ian, I forgot, there are cheaper 30s than OS....The ASP 30 is about £60

cheaper than the OS

 

ernie

[Frank Skilbeck]

I flew my Ben Buckle Super Sixty with the following engines

 

PAW35 Diesel

Irvine 25 Blackhead (plain bearing type)

OS 25 FSR

OS 40 fourstroke

 

It was some time ago but I recall they all flew it fine, but I'd say a 40 size fourstroke is the best match, or if you want a two stroke something like an OS35/40 FP would probably be fine.

[Bob Cotsford]

Judging by my 84" Eros' performance on an 48 Surpass, Franks suggestions should be about right unless you want vertical take-offs. Built light, a 30 4St might be ok but might limit it to light weather use.

[Ernie]

Hi Guys, my thinking re. a 30 four stroke, is that the last thing I want is an overpowered Super Sixty.

With mine, I could lay the tranny on the ground (not too far away) and it would fly lazy circles round my head

 

ernie

[David Davis]

You could consider a good old Merco 29 or 35. They're quite cheap on eBay. Mind you, you'd need to do something about the silencing!

[Ben B]

I'd go for a 30 size four stroke personally (although I have a soft spot for the OS FP engines as a 35 was my first ever glow engine). In my opinion the advantage is noise (or lack of it), vintage planes are about relaxed flying, more suited to the gentle throb of a 4 stroke than the buzz of a 2 stroke.

 

And the reason for 30 vs 40?

 

SC3FFS : £100

OS40FS: £180

 

[Peter Miller]

I flew my first on a Fox 25.

 

I flew aerobatics with my second which was a four channel model fitted with one of the first Saito 30s in the country .

 

An OS FS 40 would be fine, original or Surpass. Based on my Saito experience an SC 30 FS should do nicely.

 

remember that these models are flying on the wing, not brute power. KEEP IT LIGHT!!!!!

[Andy Green]

Hi Ian

 

This would do nicely. And no its not mine.

 

SORRY NOT RC - but you get the idea. 

 

Andy

Edited By Andy Green on 19/09/2011 10:33:53

[Peter Miller]

I flew an 84" span Taibi Powerhouse on the PAW 29.

[Djay]

I fly mine on a 27 year old OS 48 Surpass fs swinging a 12x6 prop.

it flies fine and with the big prop you can fly very slowly and sedately.

full throttle is not overpowered on this engine and is a perfect match.

 

Darryl

[Mark Lubbock]

We flew one many years ago (late 70s) with a very clapped out Oliver Triger 2.5 diesel, it was nylon covered & had old type full size radio gear & flew fine.

Anything with similar power to a 30 four stroke would be fine-in my opinion a 40 2 stroke would be over the top. You can always use the throttle though.

[David Davis]

It appears that the consensus is for a 25-35 two-stroke or a 30-40 four-stroke but according to Keil Kraft advert on the back page of my 1966 edition of the Aeromodeller, the Super 60 will fly on anything from a 2.5cc to 5cc. (A 15-29.)

 

I'm not sure what to put in my Charity Mass Build version. I have the choice of a Merco 35 which is traditional and British. It used to campaign a Telemaster 66 so the Super Sixty should not be a problem. I also have a brand new and un-run Enya 29, but these have cast iron pistons in cast iron bores and take an age to run in; mind you they're bullet proof once the run-in process has been completed. Finally I have an HP VT 25 four-stroke which is nice and quiet but not very powerful.

 

Guess I'll build the model with a paxolin plate and test out the HP first but put one of the others in if necessary.

[John E ( Puffin Models )]

We used to fly the standard Super 60 on OS FP 25s, and the power was just perfect for them. The aileron versions needed a little more power (for the higher air speed to make the ailerons work properly), and our choice was the OS FP 40, but actually a lot more power than was needed, though they would cruise on near idle for 10 minutes or more, and then pick up as soon as required.

 

I agree that the Merco 35 is perfect, but put a short piece of silicon tubing on the needle valve to prevent air leaking down the needle valve thread, and provide fantastic throttle response. Actually, the cast iron piston of the .29 and .35 stopping and starting 20 thousand times a second creates a LOT of vibration - the Merco 40, although not of the same time, is far more refined because of the lighter alloy piston.

 

HTH,

 

John

[David Ashby - Moderator]

I can't believe I'm hearing you say that John

 

[Peter Miller]

20,000 rpm out of a Merco 35!? What were you running it on? A 7X10 wood and 50% nitro?

[Myron Beaumont]

He's talking about each end of the stroke as being a "start stop" event ie 10,000 rpm

[Jimbo565]

Flew mine on a bog standard OS 20 with no problems,My Super Scorpion is now flying on the same OS 20,but I must agree the 4 stroke sounds better.

 

[Peter Miller]

I still say that stopping and starting 20.000 times A SECOND is excessive rpm for any engine

[Myron Beaumont]

Beg your pardon .I misread the text but I think that is what John meant to say

[ian ludwell]

I aquired a KK Super 60 about a year ago and was into my 1st year of flying and purchased a 2nd hand 2 stroke,no harsh comments now.

The engine was a Thunder Tiger pro 46.

I know what your thinking.

Are motor bikes fast?only if you twist the throttle.

This engine fitted perfectly,balanced beautifully,and flew around gracefully.

It now resides in a newer Super 60 with Ailerons and can be flown in quite breezy weather,but i appreciate it can and probably should have had a smaller engine.

 

 

[Peter Miller]

Don't worry. There was one person in another club many years ago who sheet covered the fuselage and fitted a Merco 61.

 

When the wings failed and it went into a small wood the BANG was impressive and the wreckage was spread far and wide!!! Boy! Was it shredded.

 

Well, he should not have looped at full throttle.

[John E ( Puffin Models )]

Sorry, yes, of course I should have written 20 thousands times a minute! And even then I am certain that I rounded it up quite a bit, as the revs we thought we were getting were usually quite optimistic - in the case of the Merco 29 and 35 probably VERY optimistic!

 

I never really got the fact that a piston actually has to stop at both TDC and BDC, then accelerate and decelerate in each stroke until I started to teach engine design (full size!). That could be an explanation of why engines that are way over square are providing higher than expected (or rather predicted) power levels.

 

Not sure if David is surprised that I wrote 20 thousand times a second, or the fact I was commenting on engines at all!

 

Regards,

 

John