Kitfox 1 questions

[Cloud Dancer 69]

• I too would like to see how the new Avid metal tanks are built and mounted. Poly molded off the shelf tanks with some kind of floating mount sound easier and cheaper to source and won't break down from alcohol like fiberglass tanks. Here in the Midwest finding fuel without alcohol is getting harder all the time.

[Allen Sutphin 705]

I personally don't think that the poly tanks provide any strength to the wing structure even if they are solid mounted. The poly tanks from Schrader don't fit tight between the spars like the fiberglass ones, even my 6 gal metal tank has a slight gap between the spars. Plus, the wing tank being so close to the fuselage mounting points very little strength would lost in the space of the width of the tank.  Double tanks, maybe. I am not an aero"nut" ical engineer, but sometimes common sense applies. But then, I have been wrong on occasion!

[Cloud Dancer 69]

I'd prefer a wing design that does not require the fuel tank to be part of it's structural strength. I've never seen the Schrader tank your talking about but if it's anything like this tank it should be easy enough to mount.

 

[Buckchop 479]

Yea im real new to aircraft buildin but ive built plenty of stuff in my life, and it just seems to me that one of the most important parts of the wing/airplane the fueltank shouldnt b hard mounted and made strucual if it has now structure itself to speak of,  but like i said im not good with aircraft design just my pee brain idea, and kind of copying piper design, and i should have started the discussion as a question.  Thanks to all for the opinion and facts.  

I probably wont find an aluminum tank that isnt leakin already, or most mayb have thrown them in trash/recycled. So i may just have one in the right wing only.  I really dont need the extra fuel capacity, was just copying my Blackfox 

[Allen Sutphin 705]

That tank is very similar to Schrader's tank or wingtanks.com(same).  I was going to have an alum tank made with baffles inside for strength and sloshing but with a 6 gal tank it really isn't necessary.  The poly tank was cheaper than having one made. I ended up getting a circle track fuel cell (3.5 gal) to use as a header tank to give me a total of 14-15 gal. Don't ever plan to run it that low since 1-1 1/2 hrs is about my personal limit in flight time. From experience with my intended engine, I am expecting a 2.5-3 GPH fuel burn at cruise so 20-26 gal isn't so important as weight I don't need. I am a little old school in flying so a map, my eyes, a watch, fuel planning and basic navigation keeps me on track. Plus, with these, the batteries never go dead or lose a signal. And its fun!

[Allen Sutphin 705]

A little off topic but, I just bought an engine for the model 2. A Hirth 3202 fuel injected 55 hp that can be upgraded to a 65 hp engine. Only has 30 hours or so on it. Engine is complete with exhaust, engine gages, all componets for the fuel injection system within 30 miles of me. Uses same mount as a 503 on a Kitfox. Which was the original engine it was licensed with. Weight is around 110 lbs with everything. Got it for 1/4 the price of a new one. Now to look for or build a mount.

[Cloud Dancer 69]

A little off topic but, I just bought an engine for the model 2. A Hirth 3202 fuel injected 55 hp that can be upgraded to a 65 hp engine. Only has 30 hours or so on it. Engine is complete with exhaust, engine gages, all componets for the fuel injection system within 30 miles of me. Uses same mount as a 503 on a Kitfox. Which was the original engine it was licensed with. Weight is around 110 lbs with everything. Got it for 1/4 the price of a new one. Now to look for or build a mount.

That sounds like a hell of a good deal! Hirth have a good record and I like the fuel injection since it gets rid of many of the problems caused by carburetors being leaky or not adjusted properly.

[Allen Sutphin 705]

I haven't decided if I am going to use the fuel injection system or not just yet. It is automatic adjusting for altitude and temp. But it does have a couple of electronic componets that can go bad and is electrical dependent. And it is very fuel efficient. The fuel injection is about a 2K option so I hate to just trash can it and go with carbs, which also came with it. It has a belt redrive now since it came off a challenger which I don't think has ever been used on a Kitfox.  A gearbox is probably in the works. But hey, for $2K I could not pass on it. Well, actually a tad less!

Edited 26 Nov 2018 by Allen Sutphin

[Buckchop 479]

Well did about an hr and a half worth of flyin and taxi work yesturday. Was a good day 22above but no sun. Still was AWESOME!!!!! My flying buddy Brian (in pic) said the Blackfox 0021 sure b a nice bird and it climbs like hell,  i think she will b a ton of fun. 

[Allen Sutphin 705]

You northern boys evidently are a little tougher than we hillbillies.  Days like that one, I am usually laid up in the recliner with a pot of Maxwell House. Worked out in that stuff for 30+ years and had enough of it. BTW, what engine is on the nose?

[Buckchop 479]

Ohhh man comon!!! 22 above is awesome flyin weather.  Its 8:30am and it 19 above now. But we been havin some odd warm weather so far this winter.  Hahahahahaaaa well guess if u been here 48yrs u get a little use to it but i still love my Carhartts!!! 

It has a 532 single ign, elctric start, muffler heat, B box, 68" GA Ivo, 

[Cloud Dancer 69]

Ohhh man comon!!! 22 above is awesome flyin weather.  Its 8:30am and it 19 above now. But we been havin some odd warm weather so far this winter.  Hahahahahaaaa well guess if u been here 48yrs u get a little use to it but i still love my Carhartts!!! 

It has a 532 single ign, elctric start, muffler heat, B box, 68" GA Ivo, 

You mentioned earlier that it climbed like hell; what gear ratio in your B box and what pitch is that Ivo set at? What kind of cruse are you getting at those settings? I've got the same prop but will be running it on an Avid Flyer with a 582 (same horsepower) with a Box geared at 2.58/1 and need a starting point for pitch.

[1avidflyer 1983]

If you set the IVO prop for about 6200-6250 static full throttle, you should be pretty close.  JImChuk

[Cloud Dancer 69]

If you set the IVO prop for about 6200-6250 static full throttle, you should be pretty close.  JImChuk

I need to set it to something before I can tweak it into the power band. I won't be messing with it until spring at the earliest.

The older I get the more I hate winter. I got rid of the snowmobiles a couple of decades ago and I only snow ski about once or twice a year anymore.

[1avidflyer 1983]

Well if you put it to a neutral position, and see what it revs up to, you won't hurt anything if you shut down as soon as you see you are overrevving because of not having enough pitch in the prop.  IVOs adjust so easy, I've never used a protractor on them.  Just ground run, and then add or remove pitch as needed to make the right static rpm.  JImChuk

[Buckchop 479]

Yep jim just turn it till the rpm is right is about all i know of also.  

[Cloud Dancer 69]

Well if you put it to a neutral position, and see what it revs up to, you won't hurt anything if you shut down as soon as you see you are overrevving because of not having enough pitch in the prop.  IVOs adjust so easy, I've never used a protractor on them.  Just ground run, and then add or remove pitch as needed to make the right static rpm.  JImChuk

I'm guessing it works like a guitar tuning peg; if you go too far you back it off farther than you want and then tune to prevent it from drifting? Boring heads on milling machines work the same way and you can't back them off of tension while setting them.

[Buckchop 479]

Sounds good to me.  And makes good sence to have it locked down comin up on the ramp verse comin down off the ramp so it not backoff. 

[1avidflyer 1983]

www.ivoprop.com/images/PDF%20Ultralight%20Quick%20Adjustment%20Instructions.pdf
 

[Cloud Dancer 69]

www.ivoprop.com/images/PDF%20Ultralight%20Quick%20Adjustment%20Instructions.pdf
 

I had downloaded that a while back but find it very over simplified. For instance they recommend the 6500 rpm and give no reason why you would static load it to max. horsepower. They also recommend just clipping off the ends as good enough for balance. I don't plan on cutting mine off but if I did I'd be at least performing a static balance. Maybe they do this because most people don't have the tools I do to make a precise centered hub balancing jig. They also say nothing about checking blade tracking. That's something a little harder to correct if it's off because of the way the propeller is designed.

Back when Ivoprop first hit the market some of us that were flying Mitchell Wings wanted to try them. I'm glad I didn't. On a Mitchell Wing the prop clearance between the propeller and the trailing edge is only a couple of inches. The guys that tried them found out the hard way that the Ivoprop flexes under load and it chewed up the trailing edge of the wing as well as the propeller. Being a metal wing shell laminated over a foam core made it a touchy repair. Mitchell Wing notified people not to put the Ivoprop on the Mitchell Wings but people buying them second hand don't always know these things.

Anyone here remember seeing the  propeller cross section displayed at Oshkosh back in the beginning besides me? The core was made out of blue foam back then. (Maybe they still are?) It explains why they flexed so much.

[Ronin 34]

www.ivoprop.com/images/PDF%20Ultralight%20Quick%20Adjustment%20Instructions.pdf
 

I had downloaded that a while back but find it very over simplified. For instance they recommend the 6500 rpm and give no reason why you would static load it to max. horsepower. They also recommend just clipping off the ends as good enough for balance. I don't plan on cutting mine off but if I did I'd be at least performing a static balance. Maybe they do this because most people don't have the tools I do to make a precise centered hub balancing jig. They also say nothing about checking blade tracking. That's something a little harder to correct if it's off because of the way the propeller is designed.

Back when Ivoprop first hit the market some of us that were flying Mitchell Wings wanted to try them. I'm glad I didn't. On a Mitchell Wing the prop clearance between the propeller and the trailing edge is only a couple of inches. The guys that tried them found out the hard way that the Ivoprop flexes under load and it chewed up the trailing edge of the wing as well as the propeller. Being a metal wing shell laminated over a foam core made it a touchy repair. Mitchell Wing notified people not to put the Ivoprop on the Mitchell Wings but people buying them second hand don't always know these things.

Anyone here remember seeing the  propeller cross section displayed at Oshkosh back in the beginning besides me? The core was made out of blue foam back then. (Maybe they still are?) It explains why they flexed so much.

Back around 1997/8 Ivo convinced the owner of Europa Aircraft to try one of the in-flight adjustable props on the mono-wheel 914 powered demonstrator. We put it on just before Sun & Fun, flew it about an hour and were doing ground runups with it when Ivan Shaw (Europa's owner) noticed the tips flexing thru a two or three inch arc on full power runups.  He said to remove it, box it back up and send it back. While I thought it was smooth in flight I never liked the foam core (yes the originals were foam C.D.) and really didn't like that much flex in a prop. I know a lot of people swear by them but I am not one of them. 

[Buckchop 479]

Well -14 here last few days and think im gettin to b a whimp sometimes about the cold, So decided was time to widen the doors on the Blackfox #0021.  So got a 4x8 sheet of lexan and started peelin right side door apart to change lexan and bend up a new center bar. Looks like ill get 1.75" on each side at ur shoulder, elbow, knee.  My Bluefox has this done but only 1.5" on each side. Sure makes a lot of difference on the older narrow body Kitfox and probably just as well on the earlie Avid. Ill post more pic as i get them done. 

[Cloud Dancer 69]

Are those made out of aluminum? Looks too shiny to be chrome moly or electrical conduit.

[Willja67 144]

Well -14 here last few days and think im gettin to b a whimp sometimes about the cold, So decided was time to widen the doors on the Blackfox #0021.  So got a 4x8 sheet of lexan and started peelin right side door apart to change lexan and bend up a new center bar. Looks like ill get 1.75" on each side at ur shoulder, elbow, knee.  My Bluefox has this done but only 1.5" on each side. Sure makes a lot of difference on the older narrow body Kitfox and probably just as well on the earlie Avid. Ill post more pic as i get them done. 

I've been thinking about something like this for my -1 (should i call it silver fox?). I guess you'll show your progress as you go but how are you going to form the lexan?

a few of my ideas have been

1: build a frame to clamp the lexan in and put it over a heat box until it sagged to where i wanted it and use a frame just like you're doing with the middle tube bowed out. 

2.  same as above but make the bubble oversize  so the aft end of the door touches the fuselage 5 or 6"s aft of the opening. Might look a little goofy and haven't thought about how I'd build a frame for it yet.

[TJay 1041]

build a frame to clamp the lexan in and put it over a heat box until it sagged to where i wanted it

Ha I tried that ended up with a distorted mess. I just used two pieces of lexan one for the top and one for the bottom.