aerokirk's build

[Corky]

I can't play that one it says "private" and won't give me access...{?}

[aerokirk]

Oops ... must have uploaded it with the wrong permissions .... I'll try to fix it

[aerokirk]

Fixed it

[Doozit20]

Man I would love to run on ice...that would be so much fun..

[Corky]

I watched it......Yep you're making me jealous...The boat was making a rift in the ice as you took off... it looks to be thin and likely it'll be gone in a few days...Those rudders are so cool !!! I love the way the color shifts and it looks very shiny in the sun great job they look so much better now...

[Corky]

Hi Aerokirk !!! I have a question about your build and figured I would ask this here so other members can benefit from this question...When you built your rudders I see you've used a homemade hot wire foam cutter...I've read through different sites and building one seems easy enough...My question is what wire did you end up using for the 40+ inches needed to span the rudders ??? How many amps did the wire you used require ??? Most article specs don't apply for our large span and what's needed for our applications....THANKS !!!

[txriverrat]

I am not Kirk
But on my hover craft I used a 2 amp charger and 035 stainless welding wire, Just dont get in a hurry.
Ron

[aerokirk]

Hi Corky,
I built my hotwire frame several years ago from some scrap lumber laying around. The pictures should show how I made the center pivot by cutting a slot in each side piece. The throat on mine is 42" and the wire to use is nickel/chrome which you should be able to get at a well stocked hobby store that sells model airplanes. Originally, I powered it by using three 12v car batteries that I had laying around but I found that I would have to recharge them frequently. I happened to save the position rotator power supply from my old C-band satellite dish (the big dishes) which is 30volts and does a terrific job of supplying power to the wire. I think you can find one of these pretty easily as there's alot of those old dishes collecting dust somewhere. Just mount some sort of momentary switch on the frame and you can turn it on and off easily.

The reason for the spring on the opposite end is to take up the slack as the wire heats up ... it expands quite a bit when heated.

[Corky]

Wow! perfect, thanks for the detailed pics and the parts list...I'm pretty sure I have most of the materials needed to make one and I know of a good hobby store I get supplies from that should have the wire...I've got a bunch of transformers I'll just build the framing and give one a try...Thanks again for the great pics that covered it and more !!

[aerokirk]

For those of you using a Moeller gas tank with the new EPA cap here's a word of caution ... I recently took the airboat to a waterway to spend a day cruising with my wife. It was a hot sunny day and I noticed that the tank had swelled with the internal pressure due to that cap not venting as the old ones did. The tank was actually ballooned up and distorted. Not thinking to much of it, I loosened the cap and let the pressure out when I launched the boat. When I hit the electric start the prop only moved a few degrees. Thinking that my battery was dead, I tried the starter several times hoping that it would move enough to start which it eventually did, however, the engine started making a rapping noise so I shut it down and started it again. The noise went away and like a fool, I put the pedal down and got on plane. About a mile down the water I realized that I was not making full power and was committed to returning to the dock (upwind) with a sick engine.

I think what happened was the pressure in the tank forced fuel through the carb and into one of the cylinders which became hydro-locked. I think I might have bent a push rod or worse yet, the connecting rod but I haven't had a chance to check the engine out yet so I'm out of commission for the time being. Once I see the damage I plan to write to Moeller and let them know what a piece of crap their tank cap is and order the old fashioned manual venting cap.

Be warned if you have one of these ... I'll keep you posted when I tear the engine down

[Corky]

Oh NO !! That's horrible news !!! ...Keep us posted on what you've found...I feel your pain Ted....I've read nothing but bad news about that new cap...Now it's caused you a worst case senario......How a fuel tank is deemed safe when it has the ability to baloon up and pressurize like these are doing makes you wonder who's making the decisions with all these "new and improved" fuel caps and spouts...I've hung on to my old containers and re-use the simple,retractable and/or rubber spouts if possible and also keep the old style cap with the screw in vent for the boat...Some have drilled/tapped through the new cap to try and avoid what's happened to you...
I guarantee you they'll recite the old "federally mandated" requirements but that does little for the damage it caused...
Saturn Surplus is only up the road from me...Let me know if there's anything I can do for you as you assess and repair the situation...

[Doozit20]

Thats horrible to hear about the engine issues. I hope there isnt real bad damage to the inside. Please keep us posted. Best of luck on the repairs if needed.

[Corky]

Ted,did you get a chance to investigate into your problem ???? I know how this stuff goes{damage and attitude wise} and I did'nt want to bug you but I've been thinking about this since you've posted....For me it's a process...Disbelief, a period of sinking in, then time to accept the situation and get down to it.... I'd assume a compression test would reveal the cylinder with the issue...From there it's a process of elimination easy stuff first {bent pushrods or gaskets etc..} cascading into the bigger components...

Not rushing you just seeing if you've found anything yet...

[aerokirk]

Corky,
No I haven't had a chance to investigate the damage as I just returned from the EAA AirVenture Convention in Oshkosh WI where I'm a chairman for the Young Eagles program. I'm planning to look into it sometime this week as I'm really missing our outings in the boat. I'll post my findings when I find something ... really hope it's confined to only one cylinder!

[aerokirk]

I finally got a chance to investigate my (previously thought to be) serious engine problem only to find that it was something really simple! Thinking that I had a bent push rod or worse yet, messed up cylinder, I took out all the spark plugs and did a compression test on all four jugs only to find that compression was good on all. I removed the valve covers and inspected the valves and rockers with no abnormalities noted. When I was removing the spark plugs I found that two of them were so loose that I could remove them with my bare hands. I surmise that the severe rapping noise that I had heard on engine startup was actually the impulse coupler in the magneto not disengaging due to the slower rpms of the engine (two cylinders not putting out power). The rapping noise went away when I accelerated but I didn't seem to have any power (again due to the loose spark plugs). I put everything back together and ran the engine without the prop and all seemed to be normal so I re-installed the prop and cage and took the boat out for a ride. I have all my power back now and have run it hard for two more hours without any issues.

I was surprised that the plugs had backed themselves out so far as I had torqued them the proper amount but I did re-use the gaskets (which I would never have done in my airplane) and I'm sure that played a role. I'm lucky that they didn't blow out completely taking the threads with them! Back sliding again

[Papee]

Good news. Be careful torquing those plugs. The Heli coils in those heads are just pressed in. I had one blow out, I didn't try to fix it I just put on a new head.

[Corky]

You dodged a big one there !! Man am I glad to hear that news...Aluminum parts and the heli coil inserts are very tricky regardless of what's being torqued...The plug gets torqued when cold but the expansion/contraction of the seating area{with the heat cycles} could easily work them loose...Another point I've been told is to NOT torque the plugs if the aluminum part is hot because the steel insert and the aluminum are now overtorqued and could strip right out if you're wrenching on them after the cool down {I've learned this the hard way..}...I have'nt run into this with a cast iron head and the compression ring style spark plugs....I always use antiseize on every plug I change from the weedwacker to the big cube engines...

Enjoy the summer !!!

[aerokirk]

It's been awhile since my last post, partly because I've been out playing with my airboat so much. I've gone on two overnight camping trips with it and explored several potential duck hunting marshes with great success. It's amazing the vegetation that my boat will bust through. The Quickslick bottom is amazing! Most wetlands up here have areas of relatively deep water so I'm cautious about weather conditions before venturing out. The boat's manueverability is great and it's very responsive with the airfoil rudders. I've gotten in several situations going up narrow tree lined marsh leads where they dead end with only a boat width at the end and the boat will turn on it's own radius. No mechanical issues for many hours but I do need to watch oil temp and cylinder head temps carefully. You can only run full out for limited periods with these engines before allowing them to cool down.

[Corky]

I wanted to take the opportunity to ask you after you've run the hull for a while...Did you see any noticeable improvement after the Quickslick was applied ??? Is it holding up well ??? I'm thinking hard about a bottom coating for my build... But considering there's so many rocks where I'll be running the coating might be short lived in my application... Thanks, Cork

[aerokirk]

The Quickslick made a huge difference in the slipperiness of the hull, but only noticable when running through vegetation. I haven't done a complete assessment of the hull condition yet since I put the boat in winter storage but I will probably look it over good in the early Spring. I have a quart left over from the gallon I purchased to do the hull so I should have enough to patch any gouges. I did notice several of those when I launched the boat last Fall, do mostly from encounters with stumps and rocks and the fact that I've got a fiberglass hull. I'll know more in the Spring but I am happy I put it on mine.