rdooley79

The thought of a belly tank made from spun aluminum is an attractive thought. I like it because keeping the load and CG below or slightly in front of my butt is more preferable. I don't like the idea of putting a jug behind the seat mainly for CG purposes.
 
I had a buddy with a kitfox model 1 that made a belly tank that looked like a stubby bomb. He explained that he made it stubby to keep any sloshing fore and aft to a minimum and also it was easier to mount more forward using the hard points that the gear and struts attach to. My only concern with this is the weight of a spun aluminum tank. Do you think an aluminum tank of the same size as a poly tank, which one would be heavier?
 
Aluminum has the added advantage of being strong, UV and alcohol impervious. 
 
Here is a drawing I made that is a design I like.
The top bung would be to a vent line and the bottom bung would be to a facet fuel pump to transfer the fuel to the wing tank. It would be filled by opening a valve that would bypass the facet pump allowing the fuel in the wing tank to flow in to the belly tank. Once full close the valve and the facet pump has a check valve which will only allow fuel to be pumped in to the wing tank when the pump is on. 
https://docs.google.com/drawings/d/11nmcl-nkBT9zCXp_VCQUZrX_9MpMqzEv2NPKM1NHILM/pub?w=960&h=720
 
Would look kindof like, with different fitting locations. 
http://www.aluminumgastanks.net/bombtank.html
 
 
BTW we need more topics that need a picture of a leggy bombshell posted.

I can't find the football tanks on Excalibur's site.... Where do you see them?
 
That tank you attached the thumbnail of is a "root tube" tank and it used  for quicksilver's and weight shift trikes. I've seen these up close (I've flown weight shift trikes for about 14 years) and not so sure they would be right. Would look goofey even as a belly tank.
 
I've also been searching for a way to fabricate or have a "custom poly" tank made. Not really finding much. The closest I did find is a model aircraft tank maker. They use Kevlar that can use gasoline proof resins and make large enough sizes.
http://www.jettechusa.com/collections/special-orders
 
It would be cool to have a kevlar tank that looks like a bomb with fins and everything mounted to the belly. Quick disconnects.
 
Aluminum is still just too heavy. too bad.

Joey, I totally agree. I don't need 28 gallons. I just need another 5 for 21 total. The wife and I really want to go camping and it would be nice to have enough fuel for that purpose. Really as it sits now 13 gallons usable is enough for the vast majority of the flights.
 
I can't for the life of me find where to buy the football tanks. Aircraft Spruce used to carry them, no more. Ultralightnews.com is an information site and their prices are old. No way to actually get the strut mount tanks. Does anyone know where to order them?
 
I would like to drop in another wing tank but with a wing locker that is harder than you think because the 45` internal strut is in the wing. In the KF's the tank is part of the wing structure. Without a tank and having a cargo compartment there needs to be an internal strut to stiffen the wing. I really don't want to loose the cargo compartment. It's very handy. 
 
What would be the best would be a teardrop tank that could be belly mounted and then use a facet fuel pump to transfer fuel to the wing tank. The only problem would be filling the belly tank. THe thought came to mind of plumbing from the header tank to the belly tank with a valve. Simply fill up and open the valve to fill the belly/aux tank and turn the valve off when done. Venting could be done with a simple breather line and a check valve after the fuel pump just before the wing tank supply just to ensure fuel will only go one way when transferring fuel. Also I haven't been able to find a poly tank that would be appropriate for a belly tank. 

How do you order anything from ultralightnews.ca?

I've found that 13 in the right wing even with two guys in the cockpit makes no difference in balance. I only notice it slightly when it's 100% full. Even then it's only barely noticable. 
 
The strut tanks look like a winner to me but I'm concerned about putting extra load on the struts. That just weirds me out for some reason. Maybe It's not a big deal. They do have the added advantage of being visually checked. No gauges or senders. Even if you had to transfer fuel to the wing tank with a facet fuel pump, that would be just fine. 
 
*IF* I went with a larger header tank, I'd put a fuel level gauge in the tank BUT I am with you, I consider the header as the reserve and only to be used in a time of war (quote from "Hunt For Red October", love that movie) 
 
The strut tanks seem to be the best option without cutting in to the wing.
 
I do like the bladder fuel bag that would fit in to my left wing locker. I need to be able to store extra oil for my 2 cycle Rotax 670 engine. I think this one would work nicely. kinda pricey but it is in AU dollars. Shipping would make up any savings in conversion though.
http://liquidcontainment.com.au/cartpage/viewproduct/223/15-litre-Touring-Jerry-Can
 
We now know where Bush Wheels gets their fuel bags from )
 
Is there any reason I should be wary of putting the strut tanks on?
 
Those football tanks could also be mounted on the belly side by side but filling them would be a problem. They need to be fillable at any random airport on the ramp without tools.
 
Kinda leaning towards the strut tanks. Again is there any reason I should be wary of adding 30lbs per strut?

This is a problem for me as well.
 
My KV-IV has a single 13gallon wing tank and has been "upgraded" with two of the header tanks for a total of:
13 + 1.9 + 1.9 = 16.8 gallons 
 
Typical morning flights this isn't a problem. BUT I plan on flying with the wife and doing cross countries. My engine (Rotax 670, 94hp!) burns about 4.5gph so that get's me 3+ hours with some to spare. Not bad but I'd like more for multi day trips. 
 
The two options I have are;
          1. add a wing tank
          2. expand the header tank.
 
I'm kindof leaning towards the expanded header tank option considering I won't need to cut in to the wing and the "bagage" area in a KV-IV is helariously limited. You can hang a couple duffle bags from the bars behind the seat and that's about it. 
 
Has anyone found a good header tank alternative? Poly is preferable for weight and weight. I'd also consider adding a "drop tank" under the belly as that would help keep the CG forward. I'm wary of adding another tank in series to the system now and keeping it vented properly. 
 
Carrying a can in the passengers seat is an option but not when the wife is coming along. 
 
Any thoughts guys?

Wow, those are sexy!
I love a woman with "high heels"
 
I thought that my 22" Desser's were the ultimate non ABW for the kitfox. Those are truely a ABW competitor for the experimenatl market.
 
My ONLY concern is the weight. The 22" Dessers can soak up a ton of rough terrain and float nicely on soft ground. Can only imagine how well these 27" will perform.

I've got a lot of experience with the 670 on my KF-IV. I'm surprised that "C5 Engineer" Joey, didn't point you in my direction. No matter because I'd be very happy to talk to you.
 
Hate to link to the "other" KF forum but I made a long post there. I want to get more time in my plane and then put together a comprehensive post here with all the info and lessons learned.
 
http://www.teamkitfox.com/Forums/showthread.php?p=47724#post47724
 
Anyone can drop me a PM. Always happy to talk about how awesome the 670 is. 
 
-or- 
 
Contact Rotax Rick (239) 572-0021 / faircopters@aol.com
 
 
He's got a good shop and produces a fantastic product. 
 
Both my 618 and 670 are running great.

agreed but I'm fighting some negative transfer of skills. Been flying weight shift trikes for over 10 years and have over 1000 hours in weight shift. The controls are all backwards and there isn't a tail. Going to a taildragger is prooving to be a challenge but it's coming. Problem is that the CFI I'm working with isn't as available as I'd like. I'd like to fly as much as possible but some times he's not available for a couple weeks. I've also been going through the systems of the kitfox and that's kept e out of the air too. Combination of things. I'm not in any rush to solo, just want to be super safe. It's not about the time requirement as I already have a sport pilot license. 
 
My problem is raising the tail on takeoff. P factor and the rudder is getting away from me. oddly I can land the airplane because the sight picture is very similar to my trike. In the air I'm o.k. at coordinated flight and airspeed/altitude control. Definitely need a lot more practice but it's fair enough. Really I need to get better with the rudder and aileron controls coming alive on takeoff. I'd have ground looped the plane 20 times by now if my instructor wasn't as good as he is ) 
 
 

I have nothing but great things to say for Rotax Rick. He can certainly rebuild your 582. I would seriously consider upgrading to either the 618 or 670 using the 582 as a doner "core" to offset the cost with parts like the ignition and head. Either way you'll have a great motor. 
 
I have a 618 on my trike that is an amazing motor. Just might swap the 618 to the KF but am drooling over the 670.
 
If you want to go super cheap you can always do it yourself but I can say that the parts aren't cheap and you'll have a ton of time in the project. What is your time worth, especially if you only have evenings and weekends to do the job, what are those hours worth? Rick can get it done and back to you fast also.
 
Just my $0.02 after doing a bit of engine swapping recently. 

Sent to a bunch of my friends. Got a few of them to sign it.