What a great website with a ton of info.

I had been thinking for awhile about taking the leap to taildraggers.....finally did it.....local flying club has a Citabria 7ECA.

After 1.5 hrs of upper air work and 3 hrs of laps around the airport....I was sent out on my own! Still a ton to learn!

I am hooked! Time to sell the '56 172!


Kevin

Very nice!

Congrats! There is nothing like it. I made the switch a little over a year ago.

Marty

Yukoner wrote:
I am hooked! Time to sell the '56 172!

What if your '56 172 could become a taildragger? You'd still have a large cabin, two huge doors, side by side seating, and a very useful airplane, PLUS a fun taildragger.

Hey EZ, how's that t/w STC upgrade coming along?

Majority of main gear leg design complete. Production drawings of gear legs being done now. Good for 2200 up to 2650 lb GW. Small detail changes possible but unlikely now. 1.25" thick 7075-T6 material. Approx length of early 180 for improved prop clearance and deck angle. Integral (gun drill) brake line will be optional. Streamlined cross section (quasi-airfoiled) will be an option to reduce drag (and increase sex appeal).

Tailwheel spring mounting bracket designed, initial prototyped, and now being drawin in CAD for metal prototype. Bracket size and shape now in final engineering analysis for material and gauge thickness. Stronger than 170/L-19 OEM "alligator" fitting. Attempting to make this complex bracket from welded aluminum to prevent long-term wear at rivet holes and cracks on OEM design. 4130 was cheap and easy but too stiff, applied the shear loads early to a few of the fasteners as the main structure flexed. Also must take extra care to avoid overloading that silly tail-post alum. casting, they're prone to cracking long-term. Big and expensive PITA to replace that casting. New bracket engineered for majority of loads to go "around" the casting but still using it as part of the structure.

Composite tail spring has now been through multiple tests for "spring rate", deflection versus applied static load. Results very promising, but must still be drop tested to prove dynamic loads (dynamic loads can be up to 2X static loads). Approx. 6 inch deflection at 550lb. static load means a shallower "rake" angle is possible, reducing aerodymanic drag and impact angle of rocks. f/g tailspring is 40% weight of traditional steel spring, no rust, no yield. Spring will be "fine-tuned" for softest ride without damaging rudder.

Main gear fittings and bulkhead doublers finalized, huge strength improvement over OEM (as reported previously). Prototypes final-installed, 100% verifying previous goal of installation without removing entire cabin floorboards, bulkheads, boot cowl, control tunnel, etc. Major breakthrough in simplifying installation!

Nice breakthrough made last week on the outboard MLG fitting/doorpost/floorboard tie-in shear plates. No more peeling back (up) the outer door post skin. Also significantly stiffens the floorboard in that area against buckling in a groundloop.

The tailwheel will also be up to the customer, because some customers will already have a 3200 or want to buy a used one on eBay. Some customers will want an AKBW stock 3200. Some will want an AKBW upgrade tailwheel.

Required tool list in progress, not complete. The kit will supply several special order, or custom mfg. cutting bits and a custom drill jig plate that guarantees proper hole location and not damaging bulkheads. It will be 100% necessary for the customer to have a long 90 degree air drill. I'm sorry, one of the $75 extensions that fit into your existing drill chuck will not work. My aircraft's bulkheads were accidentally damaged in learning this horrible lesson. I will probably offer a loaner drill if a customer does not have one. This is not drilling thru .032" sheet metal for an RV-6 aluminum skin... this is drilling through .063 4130 steel AND two mis-aligned aluminum pilot holes, in a confined space, with not enough room to get a good grip on the tool. The instant spikes of torque backing up through the gear train of a cheap chuck extension, compounded by having two axes of rotation 90 degrees apart, compounded by allowing relative rotational motion between the drill and the extension, guarantees that the drill bit will slam over to the right side and wreck your bulkhead.

Anyway, that's where the project is as of last night. Hotrod, sorry if this was TMI for what you asked.

EZFlap wrote:

Yukoner wrote:
I am hooked! Time to sell the '56 172!

What if your '56 172 could become a taildragger? You'd still have a large cabin, two huge doors, side by side seating, and a very useful airplane, PLUS a fun taildragger.

Looking for more HP than what I have as well....too much money to put into to this one to get it even 75% there.

EZFlap wrote:Majority of main gear leg design complete. Production drawings of gear legs being done now. Good for 2200 up to 2650 lb GW. Small detail changes possible but unlikely now. 1.25" thick 7075-T6 material. Approx length of early 180 for improved prop clearance and deck angle. Integral (gun drill) brake line will be optional. Streamlined cross section (quasi-airfoiled) will be an option to reduce drag (and increase sex appeal).

Tailwheel spring mounting bracket designed, initial prototyped, and now being drawin in CAD for metal prototype. Bracket size and shape now in final engineering analysis for material and gauge thickness. Stronger than 170/L-19 OEM "alligator" fitting. Attempting to make this complex bracket from welded aluminum to prevent long-term wear at rivet holes and cracks on OEM design. 4130 was cheap and easy but too stiff, applied the shear loads early to a few of the fasteners as the main structure flexed. Also must take extra care to avoid overloading that silly tail-post alum. casting, they're prone to cracking long-term. Big and expensive PITA to replace that casting. New bracket engineered for majority of loads to go "around" the casting but still using it as part of the structure.

Composite tail spring has now been through multiple tests for "spring rate", deflection versus applied static load. Results very promising, but must still be drop tested to prove dynamic loads (dynamic loads can be up to 2X static loads). Approx. 6 inch deflection at 550lb. static load means a shallower "rake" angle is possible, reducing aerodymanic drag and impact angle of rocks. f/g tailspring is 40% weight of traditional steel spring, no rust, no yield. Spring will be "fine-tuned" for softest ride without damaging rudder.

Main gear fittings and bulkhead doublers finalized, huge strength improvement over OEM (as reported previously). Prototypes final-installed, 100% verifying previous goal of installation without removing entire cabin floorboards, bulkheads, boot cowl, control tunnel, etc. Major breakthrough in simplifying installation!

Nice breakthrough made last week on the outboard MLG fitting/doorpost/floorboard tie-in shear plates. No more peeling back (up) the outer door post skin. Also significantly stiffens the floorboard in that area against buckling in a groundloop.

The tailwheel will also be up to the customer, because some customers will already have a 3200 or want to buy a used one on eBay. Some customers will want an AKBW stock 3200. Some will want an AKBW upgrade tailwheel.

Required tool list in progress, not complete. The kit will supply several special order, or custom mfg. cutting bits and a custom drill jig plate that guarantees proper hole location and not damaging bulkheads. It will be 100% necessary for the customer to have a long 90 degree air drill. I'm sorry, one of the $75 extensions that fit into your existing drill chuck will not work. My aircraft's bulkheads were accidentally damaged in learning this horrible lesson. I will probably offer a loaner drill if a customer does not have one. This is not drilling thru .032" sheet metal for an RV-6 aluminum skin... this is drilling through .063 4130 steel AND two mis-aligned aluminum pilot holes, in a confined space, with not enough room to get a good grip on the tool. The instant spikes of torque backing up through the gear train of a cheap chuck extension, compounded by having two axes of rotation 90 degrees apart, compounded by allowing relative rotational motion between the drill and the extension, guarantees that the drill bit will slam over to the right side and wreck your bulkhead.

Anyway, that's where the project is as of last night. Hotrod, sorry if this was TMI for what you asked.

Hey EZ, that sounds rather interesting. I'm looking forward to seeing the finished article. FYI there are a couple very cheap fastback 172's in NZ at the moment. The mandatory SID may increase the attrition rate and drop the values somewhat...

EZ - Boy do I wish your kit was ready when I found my mess, almost done with it, customers planes got in the way.

Good luck with it, sounds like a very desirable STC.

Marty