I am happy enough that my flying hasn't let me down. Being ahead of the aeroplane is what takes the attention. I think I was stopped within an aircraft's length and the yank on the gear was what busted the floor. I drove 600 miles today to see a pile of bits that was allegedly an aeroplane and had virtually no chance of being signed off. Fixing the max will be a lot quicker!
I hope you go for it Tom. The second seat in an aircraft costs a lot of money and being able to haul a passenger is some what overrated. But that is just an opinion and I hope everyone does not get their nickers in a knot.
For ITMan496: If you are looking for two seats, potentially low maintenance, and fun, look for a 7AC Aeronca Champ. I have 800 hours in them. The Chief (11AC) (150 hours) is much nicer looking, side by side seating, and not nearly as much fun. You can always get as much or more than you paid for it if you maintain it and bought it wisely. Fuel consumption is slightly less than a 447 and you don't have to buy the oil. There is no actual TBO on the engine, according to Continental, if it pulls recommended static rpm, it is good to go. I have taken several 2000+ mile trips in one. Joe Scalet
That sounds like a great aircraft! What kind of money do they usually go for in not too terrible shape? And that's impressive that you did such long haul trips! How many hops did you have to make?
Chiefs generally go for about 15K depending on engine time and condition. Super Chief (85 hp) goes for 2 or 3 k more. Champs around 18 to 20, No Champ is worth 30K. Both do around 80 to 85 mph. Our Champ had 22 gallons useful, the Chief about 21 useful. Range depends on the upholstery and your butt. Longest leg I ever did was around 4 hours. It is (almost) always fun.
We're getting close on the "Epic Sport". David is pretty meticulous and has re-done the control system in an iterative manner, making it better each time. At present it is just about what I was thinking of doing on mine. I'm pretty sure the performance figures on an "Epic Sport" will beat a "Chief" when we get them tested out. This type of construction is lighter for the given strength than you would have in the "Chief". Taking nothing away from the "Champ" or "Chief", which are indeed great aircraft for about a minimum price for a "Chief" you can build your own "Epic Sport" and have a brand new airplane. This is just to provide another perspective.
Development of the "Epic Sport" has taken a long time. Let's face it David is just buried in work and has to work on this new design in what might be called stolen minutes. However it shows every sign of being a great aircraft when it is completed and tested. This is a conservative type but the construction's weight advantage should make it a really great weight carrier and performer.
An all wood 2 seater with VW engine on this theme would be great.All of us cant learn how to weld. You just have to design the fuselage and tail as the wing is already there.
I'm nearing the end of my Max build and saw the post listed below and am uncertain exactly what the piece(s) look like that are being described here, can someone elaborate on these "flip over avoidance fairings""? Thank you Kim Brown New Hampshire
So fair it!
That's what I did and what Tomshep's aircraft has.
A long time ago it was explained to me that a round axle tube will be grabbed and 'whip-wrapped' around by grasses and similar vegetation. It was said that if there is a horizontal aspect to the axle that effect is less likely. Added to that you get free drag reduction.
I fitted cut-up scrap Airwave Magic IV hang-glider uprights to fair the axles on two Minimaxs. Lightweight and strong enough to take on the plains' grasses.
I went to my local model shop. Bought four feet of 1" le and eight of 1/2" x 2" te balsa. These I hollowed to fit around the axle. I affixed them with a couple of dots of glue and covered them in sticky dacron.
OK, so these devices are what you would use if you were making the round axle more aerodynamic, it is just the reason is tip over avoidance rather than air drag reduction, theory being the grass might get cut rather than wrapping itself around the round shape of the axle. Thanks. Kim Brown New Hampshire
No, it is a side effect. The grass certainly does not get cut but it does get pushed out of the way a little. The drag reduction though is noticeable when flying because the reduction is so far from the thrust line that the aircraft seems to be slightly less pitch sensitive to power changes.
Any streamlining and fairing makes an enormous difference in performance. Every time you fair something you tend to gain top speed, or put another, way reduce fuel consumption for a given speed. Kitplanes occasionally has articles on this. The most complete work on this is "Fluid Dynamic Drag" by S. Hoerner. This has all the technical information but is arranged so that you can pretty much figure out what you need to do without having to work any math. A less technical but very informative book is Kent Paser's "Speed with Economy".
Several years ago at Gardner, K34,Airport, the center of the grass runway was allowed to grow. A Graham Lee replica Nieuport II flipped over when the grass tangled with the tubular steel axel. So it is not uncommon.
My max103 flipped because of a small drainage crevice among the brush that caused the landing gear to depart the aircraft. Since there is no guarantee on how you’re forced will end you should be prepared on how to escape if it happens. My shoulder harness restricted any movement till I was able to cut it with my knife. Now I use a quick release on my Airbike. The turtle deck gave me approx. 8 in of space to crawl out. If I did not have it I would probably still be there. Now I always carry a knife and a charged phone.
The metal landing gear option may help avoid flipping over in some way.
Only just noticed the different undercarriage on that Minimax. I must be getting old. Just for fun:
Where would the forces get resolved when I *plonk* that aircraft down hard due to lack of attention or a forced landing?
Seems to me the wheels would want to go outward because the mass of the wings decelerating downward and pushing them inward would be less than the mass within the fuselage decelerating down and pushing them outward.
So I reckon there would be a squeezing force instead of a '45 degree force' on the sides of the fuselage floor you'd expect with the standard set-up. Would it not have to be re-inforced to react that squeeze? Maybe it is. In which case apart from that slight added complication it looks like a good idea!
Where would the forces get resolved when I *plonk* that aircraft down hard due to lack of attention or a forced landing?
This gear is no different than the one with the straight tube between the wheels. Instead of a straight tube, this one uses a welded frame that has no flex between the wheels. The loads on the wings and fuselage are the same.
As on all Minimax's, the landing loads are softened by the fat tires.
My guess is that with the CG being very close to the main gear (on the aft side) in a tail wheel plane, the nose-over tendency is always lurking in a tail wheel plane in any type of landing. The abrupt deceleration caused by the wheels or axle being force-stopped by an obstacle in an off-field landing, merely hastens the nose-over process.
The CG being very close to the main gear is also the reason tail wheel planes ground-loop easily.
Of course the placement of CG is also related to where the center of lifting forces act, in order to maintain pitch stability in flight. So two different considerations dictate where CG rests in a tail wheel plane. And both have to be satisfied to get the proper design.
If CG is too far back from main gear, (assuming somehow we manage to get the CG in its proper place in relation to lift), the plane will have less tendency to ground loop, because now you will need a larger moment or force, to initiate a ground loop. But unfortunately, this placement will also make it difficult to lift tail on the take off roll, and it will also necessitate a heavier and more robust tail wheel. So this alternative is usually not desirable. And usually it will also make the positioning in relation to lift, out of whack.
On the positive side, because CG has to be fairly close to main gear, hardly any weight is taken by the tail wheel, so we can get away with a shopping cart wheel.
Nose wheels in a tricycle are usually bigger than the tail wheels in a tail dragger, which is a visual clue that nose wheel takes more weight than tail wheel in a tail dragger. The distance by which CG is displaced forward of main gear in a tricycle, is MORE than the distance by which CG is displaced aft of main wheels in tail dragger.
I try to visualize a tail dragger in my mind as a plane which when on the ground, balances itself mostly on its main wheels, because CG is so close to main wheels. The tail wheel is there merely to balance the plane and to keep it from tipping over, no more.
I dont have my plane's weight distribution on the 3 wheels right now, but that will most likely support the above hypothesis.
"Where would the forces get resolved when I *plonk* that aircraft down hard due to lack of attention or a forced landing?"
Same as the flight loads which are greater by far.
"If CG is too far back from main gear...the plane will have less tendency to ground loop"
No, having the cg behind the mains is less stable and therefore the further aft the cg, the greater the tendency to ground loop. And in the 3 point attitude, the cg is moved substantially far aft when compared to the entire 4.9" cg range, so trying to reduce ground loop tendency by cg adjustment is not worthwhile.
>>>>>>No, having the cg behind the mains is less stable and therefore the further aft the cg, the greater the tendency to ground loop. And in the 3 point attitude, the cg is moved substantially far aft when compared to the entire 4.9" cg range, so trying to reduce ground loop tendency by cg adjustment is not worthwhile.<<<<<<
In a ground loop, I am assuming the plane turns sharply with the inner main wheel as the fulcrum. When the CG is closer to the main wheels, less force is required to swing the tail of the plane around.
As an example, lift the tail wheel physically while plane is on the ground, and try swinging it sideways to the left, with the right main wheel almost stationary, and note the approximate effort required to swing the tail through a certain arc of say 10 degrees.
Now repeat this by moving CG more aft. One way to do this, is by adding a 15 lb weight near the tail, and repeat the same exercise. I feel I will require a larger effort to swing the tail through the same 10 degrees because the CG has now moved more back.
As I said this just my hypothesis, and I have felt this holds good in different ways that I see this working in reality. I don't claim this is the absolute truth. If the stability method makes more sense, that is also fine.
"In a ground loop, I am assuming the plane turns sharply with the inner main wheel as the fulcrum."
The rotation is around the cg. The cg is the fulcrum or pivot point. Weight(friction) on the tail wheel is stabilizing provided the pilot inputs a correction but it is small compared to the weight(friction) on the mains and the long tail moment won't help once the mains have gained sufficient moment of their own.
Logged
