herman pahls

Ken
I deleted my post till I figure out how to get the photo straight.
Herman

Hi Larry
I am having a hard time getting excited about a project 2500 miles away.
I am curious why if it is a good deal why it has not sold yet.
Maybe it has.
Herman

Hello Doug
Your spring comparison photo was just what I needed.
I was concerned that the 3 leaf spring would raise my tail more than the 2 leaf and it appears it will not. 
The 8" wide Matco tire is a  huge improvement in the sand but unfortunately it raises the tail  2" higher than when the 6" hard rubber Maule tail wheel is installed.
I was hoping the 3  leaf would not raise the tail even more.
The more Angle of Attack my Kitfox has the shorter it takes of and lands.
 
I just read the info. on your recent aircraft purchases.
Sounds like you have owned several Rotax 912's .
Let me know if you know of one for sale.
 
 
Thanks again
Herman

Thanks for the tail wheel spring info..
The consensus seems to be the Kitfox 3 leaf so I will order one.
I also store my Kitfox wings folded and the Matco 8" tailwheel leverages the spring more than the stock Maule 6" wheel.
Herman
 

I am very interested in this discussion regarding whether to vent the header tank or  not because of the serious consequences.
A few months ago a friends Avid went down (passenger will never walk again) and he felt that he had fuel starvation because his behind the seat header was not vented.
Both of his  wing tanks fed the header tank with shut off valves and one line drained the header forward to the firewall gasculator.
A few years ago I had my one and only forced landing in 36 years ( which was fortunately a none event) and was likely due to venting or carb ice.
I have the 8 gallon cowl tank (header tank) which is fed by one wing tank.
The only vent at the time was the wing tank filler cap ram air tube.
My Kitfox gets hangered with the wings folded so possibly the fuel line/vent tube got pinched in the folding/unfolding process.
The only solution I could come up with was to vent the cowl tank fuel cap and now if I forget and overfill the cowl tank when transferring fuel I get reminded with fuel on the windscreen.
So here is my question.
How can venting the behind the seat header tank  be a negative?
I like the #11 post where DeeJayel uses the vent line as a sight gage.
It seems like all the highwing airplanes I have owned are gravity fed, do not have header tanks but they do have both fore and aft drains out of the tank.
So regardless of nose up or down attitude the available fuel will drain.
Most of our Avids and Foxs only have rear fuel drains.
So what happens if you are only feeding off one tank and it is getting low enough that air enters the drain line.
Even it you are feeding off 2 tanks.
How does that air get out of the header tank without a vent?
If you have huge fuel lines I can see the air burping back up the fuel line but it would not burp as easily with the 1/4 or 5/16 ID fuel lines that many AvidFoxs use.
I road race Formula cars that corner at 2-2.5 G's.
At less than 1/2 fuel the G forces will allow air into the fuel pick up, just like banking the wing on a less than full tank.
In race cars we all use some sort of internal or external surge/header tank to prevent air from getting to the high pressure fuel pump and to be able to use the last quart of fuel.
Those surge/header tanks are all vented back to the top of the main tank because that is the only consistent way for air to escape.
It sure seems like without a header tank vent we are playing "Air Bubble Roulette" when ever air gets between the fuel and header tank.
Please let me know what you think.
Herman

Thanks Randy for responding.
I asked the same question in TeamKitfox and was directed to some past threads.
Seems like the impressions varied from no difference to some difference in stall speed.
Almost all felt the control authority improved with VG's.
I feel my Model 2 control authority is fine so I will probably not try VG's.
I will be interested in your results since my Kitfox cruises quite slow and burns a lot of fuel with it's under cambered wing and 582.
Herman

I have towed my Kitfox thousands of miles on vacation.
All the above advice is important especially using the softest sprung trailer you can.

Joey
When I installed the 20 pound heavier Jabiru several years ago I used the flapperons to trim out the nose down instead of adding tail weight or a trim since the CG was still in range, just further forward and I did not want to add weight.

The airplane flew terrible in comparison to with the 532 and it took almost 2 years until a Kitfox flyer in Idaho told me on a forum that the flapperons were probably reflexed too much.
Sure enough he was very correct.
The bad symptoms that too much reflex caused on my Kitfox was higher stall speed since I did not use flaps at the time, less elevator authority, very heavy aileron stick forces and heavy right wing probably due to unequal flapperon reflex.
Plus I did not enjoy flying it anymore.
I am not sure how much this applies to your wanting more elevator but seeing reflex on your post brought back mistake in the past.
Herman

Hi Marv
I was hoping some one would respond to your question.
This forum has attempted to gather  Rotax 670 information for years but there has been very little feedback from what I have seen.
I fly a Kitfox and many others who have Avids would consider replacing our 582's with 670's if there was more feed back to back up Rotax Rick's claims.
I purchased the exhaust from Rotax Rick 2 years ago  that was to fit inside the cowl of a Kitfox with a 670 and it would not come close to fitting when I mocked it up with my 582 which is virtually the same size as a 670.
That exhaust ended up in Alaska and the new owner thought at first it would fit without modifications in his Kitfox and then months later told me it would not fit.
Currently there is a Kitfox for sale in Florida on Barnstormers for 15K that has a newly installed 670 with 17 hours.
I called the owner just to ask how the 670 install went and he told me the exhaust  did not fit as promised and he had to modify it.
He sent photos and the muffler is installed right to left like a 582 kitfox exhaust.
The photos that Rick sent me of a flying Kitfox which had the exhaust he promised to send me had the muffler oriented front to rear.
I would be possibly be flying a 670  today if the exhaust would have been as promised.
I know this is a long and round about way to answer your question.
I assume the Avid 670 install would be upside down as it is with the 582 so the exhaust would not be the same as the Kitfox install.
Rotax Rick is a very friendly and helpful and loaned me the puller to install my RK 400 clutch.
I feel he knows his Rotax engines but something is missing when it comes to the exhaust fitting on the few cases I know of.
Herman

Joey
I just noticed your thread creep and I enjoyed the video.
I ride a KTM 2 stroke and technical single track with water crossings is the kind of riding I go out of my way for.
I just came to the realization that my dirt bike and Kitfox have similarities.
I am considering 4 strokes for my next dirt bike and airplane engine.
Both have been modified with centrifugal clutches.
Neither have ever failed me.
Herman

The die hard or is it jealous 2 strokers are sure having a good time with any weakness's in the 912.
So is the 912 vibration due to carb mounting a common issue on the Model 4 since I am hoping to own one in the future?

Crazed pilot has a model 5.
The design of the Model 4-7 flaperon linkage which requires disconnecting the push rods to fold the wings solved 2 problems that  many of us with older Avid's and Fox's are trying to solve.
It gave differential flaperon movement for less adverse yaw (which we are trying to resolve with the F7a bell cranks) and opened up the area behind the seat for a true baggage area.

I will also be interested in the F7a bell cranks if they fit a Model 2 Fox

I also see Leni's point.
Say you buy a serviceable Pacer for 25K.
It will burn 3-4 gal/hour more than the 38K Kitfox and cruise faster than a Kitfox with the same size tires.
At $6.00/gal for avgas it will take 620 hours flight time to break even on the higher cost Kitfox versus the higher fuel burn Pacer.
If you do not have the repairman certificate for the Kitfox you will need to pay for the condition inspection as well as the the annual for the Pacer.
If you need folding wings or a Light sport license than the Pacer is not an option.
 
Herman

I had a hard time getting the idle rpm down since there is no longer a load on the engine, to prevent the chatter that sioux201 refered to.
I ended up machining the carb. slides on a lathe to reduce the size of the cut out which allows air for idle.
Others like Leni were able to get the idle RPM down with carb adjustments only as I recall.

Dave
Great storage idea that I never thought about.
My Kitfox is also covered with fabric under the turtle deck like yours is.
I was going to remove the fabric to install the storage sack as was shown earlier in this thread.
If I send you my cell phone will you take some photos of how you lined the compartment fore and aft and above the elevator pushrod? L.O.L.
At least you know how to post photos and I am clueless.
Thanks for the great idea.
Herman

I would have a hard time going back to flying a 582 without the clutch.
Start up and shut down are so smooth without gear box chatter.
The clutch has to make life easier on the gearbox and crankshaft.
It starts so easy (think snow machine) I would consider a rope starter to cut down some weight.
Tell us how it works for you.
Herman

This discussion is driving me bonkers.
Why, it is making points for the Grove gear mainly due to it's simplicity in spite of adding approx. 12 pounds over original gear and who knows how abusive Grove gear is going to be to the longerons and bungee truss when the going gets really rough.
I really want Cub style gear (if it is really better than the alternatives for rock bashing) and I have spent weeks researching how to do it correctly on my Model 2 Kitfox.
I do not like the advice I have been given.
My Kitfox's longerons, seat-bungee truss and lower door frames need to be replaced with bigger tubing and more bracing and that is major surgery.
And why do I want to consider all this?
So I can Adventure fly to where airplanes were not intended to land.
What better thing to do with an airplane that I could almost drive there faster than fly.
My wish for Joey's thread is to come up with a gear design that requires minor surgery to the fuselage and will take much more bashing than stock gear.
FoxDB's post #14 regarding how the compressive loads are directed towards the longerons needs to be addressed.
Trackwelders post #8 regarding triangulating the Cabane V is right on IMO.
A simple tube across the top of the V would help both longerons to share the loads and minimize the longeron twisting I believe.
Notice Joey's 9th photo of the front view of a white Rans S-7 with Roberts Gear.
The gear and cabane get bolted to their own brackets so the compressive forces do not try to twist the longerons.
Both the Highwing and Joey's gear use the same bolt for the front gear leg and Cabane.
This makes the install very simple since new brackets do not need to be welded on the longerons.
This also becomes a compromise because I feel we really need bigger than 1 inch diameter front gear legs to prevent Joey's front leg collapse.
They say tubing diameter has more to do with compressive strength than tubing thickness.
My Kitfox brackets are 1-5/8" inside. It would be challenging to pinch down 1-1/4 tube and weld it to a slug and not exceed 1-5/8's width let alone room for the Cabane tabs to go inside the Brackets.
John Rodgers from Homedale has a unique style cabane gear he built for his Model 4 Kitfox.
His Cabane V if you can call it that, is welded to a reinforced seat truss and he uses 1-1/4 diameter front gear leg.
Anyone know how John Rodgers gear works.
Enough for now.
I am counting on you engineers.

Joey
How much travel does the machined groove have on your spring strut before it goes metal to metal on the safety bolt?
From what I can see through the spring it only looks like 3 inches of strut travel.
Do you have any idea how many inches your tire will travel if you were to cycle your suspension without the spring in place?
I assume you are getting more travel at the wheel than the strut travels,  like a dirt bike has 12" of wheel travel and the shock only travels 2.5"