Super Kraft EXTRA 300S/40 Engine
 

Hi All-
I've got one of these on the way. And I'm wondering how much engine it can take. The instructions say 40-52 2 Cy or 53-80 and 5.5 to 6 lbs. I'd rather err on the side of over powering it. I can always throttle back. Is there a sub $200 4 stroke that would do the job? This would be my first four stroke. I've got some 2 stroke experience. But I've flown mostly electric for the last two years.

Oh, and if any one has any hints on assembling this model I'd love to hear them.

Thanks
Mum

Super Kraft EXTRA 300S/40 Engine
 

A freind of mine has one and he flew it all last summer with a TT46, and it flies great with this engine. I would go with the Irvine 53 2 stroke, or a 80 size 4 stroke, either would be awesome on this plane, maybe a 91 4 stroker too, might be a bit much though.
If your looking for a good 4 stoke 91 for $200.00 go with the Saito, or even magnum. I would recommend the Thundertiger, but it has a few more ounces of weight which you dont really need on that plane.
The plane builds up nicely, with no real modifications needed. You might want to change your pushrods to fiberglass, other than that it is a good little bird. Daz...

Super Kraft EXTRA 300S/40 Engine
 

Daz-

Thanks for the input. I'm particularly interested in the Magnum 91 because I may be able to trade some unused Electric stuff for a Magnum. You mentionded that a 91 may be a bit much. Did u mean weight or power wise?

Thanks
Mum

Super Kraft EXTRA 300S/40 Engine
 

A magnum 91 would be ok if thats what you have, just remember the heavier the engine the more weight your gonna have to add to the tail to balance correctly, resulting in an overall heavier plane. Keeping the plane light is beneficial. The lightest 4 stroke is the Saito 91 weighs, 19.6 ounces, and a 2 stroke 46 is average around 17 ounces. Try to keep the engine weight between these weights, or not much more. Daz...

Go with a 91!
 

The 91 will weigh the same as an 80. You will need all of the extra power if you want to climb out of a hover. Go with a 4 stroke, the power is more manageable and throttle response quicker. You will be happy with a Saito, ounce or two lighter than the Magnum. Magnums run ok but their workmanship doesn't even compare to Saito or OS. If you go with a Magnum, handpick it if possible. Check for excessive end play on the crank and smoothness of the throttle barrel operation.

Super Kraft EXTRA 300S/40 Engine
 

Daz-
Thanks again. The plane arrived today. Fantastic service I paypalled on Friday and they shipped it the same day. Anyway, I'm going to trial fit the components. Seems as if I can move the batts and servos around if I need to with just a bit of work. I don't care much about the few extra ozs in the nose. But If I need to add a lot of weight to the tail then I may go two stroke.

BTW, magnum lists the weight as 22 ozs. Any idea if that includes the muffler?

h82crash-
I'm considering the Magnum because of a trade offer. Are these problems common?

Thanks
Mum

Super Kraft EXTRA 300S/40 Engine
 

mumblety, I'm quite sure 22ozs includes the muffler, if you need a little extra weight in the back I'm sure you can obtain your CG with your battery mounted in the rear of the fuse. Daz...

Super Kraft EXTRA 300S/40 Engine
 

Daz-
Thanks for all the help. 4 stroke it is.
Mum

Super Kraft EXTRA 300S/40 Engine
 

No problem Mum, I'm sure you will enjoy the Super Kraft Extra, it is a very good flying bird!!! Daz...

Modifications for Larger Engine
 

I just got my Extra 300S/40. It's the new red, white, and blue color scheme. This ARF is beautiful!

http://www.atsrcplanes.com/Extra40NEW2.JPG

I want to put my OS .61 SF ABC (2-stroke) in it but the holes (and blind nuts) in the firewall are drilled for a .40 size engine. I'm wondering if anyone's modified this plane for a larger engine than called for. I've never done this before and I'd rather not be the guinea pig if I can find some advice... :confused:

Also, I'm wondering if anyone recommends any other modifications to it. I hope to wring it out for all it's worth...

-- Dustin

Super Kraft EXTRA 300S/40 Engine
 

I'm using a Magnum .91 FS. Installing a different engine is not hard if u have small hands. I don't. So I had to dremel out a ply bulkhead a bit so that I could reach the blind nuts.

I don't recall much in the way of mods. I think I mounted the servos a bit differently. Just to move them back to help with the CG. And the langind gear was too soft for my poor landings.

Have fun with it.

Mum

Super Kraft EXTRA 300S/40 Engine
 

How do you pull the blind nuts out? Also, did you redrill the upper holes or the lower holes? Did it affect performance at all?

Super Kraft EXTRA 300S/40 Engine
 

To remove the blind nuts just tap them out from the fron of the firewall. I used the supplied screws and and a hammer. Very light taps till the nut comes out.

I think I needed 4 new holes for the motor mount. I don't recall exactly how I arrived at the correct spot. Probably mounted the motor to the mount first. Marked on the firewall the correct position for the crankshaft and then marked the outline of the mount on the firewall for the mount.

I can't say how the plae would perform with the a 46 cause the only engine I've used was the 91. I think a 61 would be perfect.

I hated installing the elevator split pushrod. Other than that I was a straight forward assemby.

Super Kraft EXTRA 300S/40 Engine
 

Thank you. That makes sense. I think I'll do it just as you suggested. :)

Super Kraft EXTRA 300S/40 Engine
 

Has anyone fiberglassed the main wing joint? I've built kits before that called for this but I don't think this one does. Does anybody have any strong opinions about that? :confused:

Modifications for Aerobatics
 

What kind of structural modifications does this plane require for unlimited or 3D flight? :confused:

Super Kraft EXTRA 300S/40 Engine
 

I'm puting an OS .61 SF ABC in this plane. The designer of the plane recommended puting a 1/16" shim on the left side to give it more right thrust with this engine. Has anybody tried this or do you have an opinion about this? :confused:

Super Kraft EXTRA 300S/40 Engine
 

I'm thinking the stock fuel tank might be a bit small for my .61 engine. What do you guys recommend? Or should I stick with it?

If you recommend a larger size tank, what size and what kind of modification would it require? :confused:

Super Kraft EXTRA 300S/40 Engine
 

I don't know what size. But u can fit anything u want. Just need a dremel to shave the ply bulkheads.

Super Kraft EXTRA 300S/40 Engine
 

Thanks for all your help, mumblety-peg. :)

Super Kraft EXTRA 300S/40 Engine
 

Glad to help. Now I feel motivated to get mine ready for spring.

Super Kraft EXTRA 300S/40 Engine
 

Has anyone used the Rit method of tinting the canopy? How did you do it and what were the results?

Super Kraft EXTRA 300S/40 Engine
 

I tried it myself and got excellent results. :)

Super Kraft EXTRA 300S/40 Engine
 

I made the forked elevator pushrod like the instructions say to do but it is very tight and doesn't like to slide due to the friction of the forked wires rubbing on the fuse as it passes through the holes. The instructions don't say anything about a bend in the pushrod wires but I'm thinking this may be necessary. Are the instructions wrong? Is there supposed to be some kind of bend so the wires aren't straight (besides the one that says that each fork (at the end) should be 2 1/2" from the other one)? :confused:

Super Kraft EXTRA 300S/40 Engine
 

I ended up using a Dremel tool to make bigger holes for the pushrods through the formers and was able to get it to work. :)

It's a great plane and if flies very well. I love it! With my engine, the .61 SF ABC, the 13/6 prop works best for me.