Any Kolb firefly guys here

[David D]

I have been home for a couple of weeks recovering from a back problem. Doing a lot of reading and thinking. I have a ppl but job changes and such not enough to money to fly. I'm kinda eyeing a firefly, but am a little concerned about a two stroke. Does anyone know if there is a 4 stroke that would work on the firefly. I live in western Ky, probably less than an hour by air to where the kolbs are made. When the runway drys up I'm gonna try to fly there. Just want to have some ideas to take with me.

 

 

[fly_tornado]

you need to look at a mark 3

 

 

 

[David D]

Yes, I seen that one. Very cool! I'm still learning, but are those LS? I don't know anything about ownership. How is this different than owning an ultralight? Registration insurance etc.

 

 

[fly_tornado]

all the kolbs are LS compliant. you should get better insurance rates with a 912 than a 503-582

 

 

[Doug Evans]

Nothing wrong with two strokes if looked after mate I been flying behind one for twenty years plus no problems

 

 

[David D]

May have been you mentioned that before. I talked to a local guy who says the same thing. I think I have learnt that proper rpm and loading while flying control the mixture and heating. It seems like there are two speeds that they run in. A high idle or wide open? I have done quite a bit of reading, but must be missing something. I don't think I understand, say a sequence of throttle events of a flight, relative to temp control. In a 150 I would in different maneuvers use all the speeds in the green arc, and idle with carb heat on some. Could you explain an example of throttle settings during something like lazy eights, and or a power off stall. I'm not understanding how you manage the head/piston metal exchange of heat. When I watch utoob it seems like the work the throttle a lot on touch and go's. How is that? I'm sorry I don't know correct terms for some of this.

 

 

[Doug Evans]

Well I can only speak for my own management of the engine and I always make shore I have good engine temp before using full power settings and only use smooth and steady applications of power setting my craft runs a

 

RK 400 clutch which allows for a slow idal speed which I beleave take a lot of stress out of the crank when at low speed running so it will run as smooth as any four stroke .

 

As for temp management I do a lot of touch & gos and found the little two banger enjoys doing that type of running

 

But on descents I keep my engine at a power setting too allow keeping some temp in the coolant so not too drop temp too quickly Also the fuel running the engine will also cool your Pistons so that will help prevent nipping these little burgers like too rev I have my prop pitched to gain a max take off rpm of 6400 rpms and I cruise at 5800 rpm but will happy run at 6000 all day but us more fuel. 21 lph @ 5800 I get about 17 Lph I found that having the oil injection sys works a treat much more dependable these days then the older system so for my money I won't go past these little engines atwo strike will cost about $600o to replace and I know of quite a few that have done a 1000 hrs and still going strong with the right care .

 

Doug

 

 

[David D]

Thanks for the info guys. The more I learn about this, the more I need to learn. Another question, if I were to buy a used ultralight. How does the insurance work? Is it liability, or does it cover the aircraft, the pilot, or all of those?

 

If buying used are there ways to have a mechanic do a routine check for signs of trouble, I realize there is no sure fire way, but just a reasonable check?

 

Would there be registration requirements?

 

I am going to try to visit the Kolb place in a few weeks. I know I will come home a bit sad because I won't be able to afford a new one. I will be for me like visiting my favorite guitar shop and leaving empty handed. Hey but I'm goin anyhow.

 

Thanks David

 

 

[Doug Evans]

Thanks for the info guys. The more I learn about this, the more I need to learn. Another question, if I were to buy a used ultralight. How does the insurance work? Is it liability, or does it cover the aircraft, the pilot, or all of those?If buying used are there ways to have a mechanic do a routine check for signs of trouble, I realize there is no sure fire way, but just a reasonable check?

 

Would there be registration requirements?

 

I am going to try to visit the Kolb place in a few weeks. I know I will come home a bit sad because I won't be able to afford a new one. I will be for me like visiting my favorite guitar shop and leaving empty handed. Hey but I'm goin anyhow.

 

Thanks David

Can't help with that question David as I live in Qld Australia and shore it be different at your end of the world

 

 

[JSW Firefly]

Kevin Armstrong

 

Here is your 4 stroke engine for the Firefly.

 

 

[winsor68]

Kevin ArmstrongHere is your 4 stroke engine for the Firefly.

Your third video from the top shows an engine failure and crash... The comments indicate a solution???

 

 

[JSW Firefly]

Failure was due to Briggs and Stratton weakness of a hollow cam. You must know that this engine is a Briggs and Stratton Vanguard V-Twin 23hp model 38. However basically the only stock parts in it are the block casing and the crankshaft. All the rest are basically from here:

 

Performance V-Twins - Monroe, NC

 

It is called and Eagle IV tune.

 

Although the rest of the parts are solid, the performance cam, which is milled from an original Briggs blank, is hollow. The Solution that Kevin Armstrong uses, is used by Precision Cams which is to hone out the center and insert a hard steel rod for strength.

 

If you follow his Youtube videos, you will find that this engine was to replace the 447 Rotax his plane was designed for, and has flown successfully for over two years before this failure. I have purchased the engine and all the identical parts from Performance V-Twins, including the belt redrive that he designed, but have not yet assembled mine. I now have the same cam that is prone to failure. The solution that I am going with is to replace the cast cam with a billet steel cam ordered from Precision Cams. This cam is good for 5000 rpm and 4200 - 4500rpm continuous and is much stronger than the cast cam which was designed for the stock 3600rpm.