Just realized that I have not posted anything on this project on BCP...So I have cut and pasted my starter thread from SC.org as follows....

For several years now we have been working on a STC to convert a PA-28 Cherokee into a tail dragger.....Why you might ask....because its different and no one else has done so with the exception of one "one off" conversion with the gear flipped around on the wing spar. Our concept is to use a one piece gear leg bolted onto the bottom of the fuselage at the forward bulkhead just in front of the seats. We are bolting the system into the fuselage with a couple of machined blocks in the interior and a spacer plate on the bottom of the frame. The blocks and plate are bolted through some of the main structure of the frame thus transferring the gear loads throughout the fuselage structure. The gear leg is made by Grove and is gun drilled for the brake lines.

I have included pictures of our fuselage that we are using for drop testing and mock up of the system. We have a certification letter in place with the FAA that was written by a DER. Once we get the tail wheel system figured out, we will proceed with loading the airframe up to gross weights and then doing a series of drop tests.


















Questions and comments are welcome.

Brian.

That willl be cool to see when its all done. Put some bushwheels on it!

Will it improve take off performance? I was looking at the Grumman AA1 conversions and they say it uses a lot less runway with their conversion. They also claim another 10 to 15 knots of cruise at the same power setting.
I sure does look cool, and if there is a performance increase, would be something I would sort of interested in.

Whats the model in solidworks of?

behindpropellers wrote:Whats the model in solidworks of?

Looks like the torque tube for syncing the tailwheel steering and rudder?

DavidB. wrote:Will it improve take off performance?

No. Same wing and same HP. Unless it weighs a lot less it will take off and land in the same distance. Just like a 182 vs a 180.

Bonanza Man wrote:

DavidB. wrote:Will it improve take off performance?

No. Same wing and same HP. Unless it weighs a lot less it will take off and land in the same distance. Just like a 182 vs a 180.

Higher AOA = flies sooner, no?

Usually any performance increase in a conversion comes from less weight of the nose gear, and then less drag by not having nose gear either.

There's at least one PA 28 taildragger out there. I saw a picture of it in the early 1990s in the Piper Owners Magazine or Cherokee Owner's Magazine, a publication of a an owner's group I belonged to at the time. From what I remember, it still had the oleo strut main gear which was smoehow moved forward to near the leading edge of the wing. I don't know if it was N8430W, which is listed as an early PA-28-180 converted to a taildragger.

Best Regards,
O-2

Bonanza Man wrote:
DavidB. wrote:
Will it improve take off performance?


No. Same wing and same HP. Unless it weighs a lot less it will take off and land in the same distance. Just like a 182 vs a 180

My understanding has been that a 182 of same weight and horsepower as a 180 would take off shorter, probably fly slower, with each having propper rigging.

I figured the182 accelerated quicker because the tail was already in the air and could accelerate quicker. Then as it reached rotational speed, it could rotate farther because there was no tailwheel in the way,getting a higher AOA.

Faster because of less drag from the tailwheel than nose wheel.??

Gary

shortfielder wrote:

Bonanza Man wrote:
DavidB. wrote:
Will it improve take off performance?


No. Same wing and same HP. Unless it weighs a lot less it will take off and land in the same distance. Just like a 182 vs a 180

My understanding has been that a 182 of same weight and horsepower as a 180 would take off shorter, probably fly slower, with each having propper rigging.

I figured the182 accelerated quicker because the tail was already in the air and could accelerate quicker. Then as it reached rotational speed, it could rotate farther because there was no tailwheel in the way,getting a higher AOA.

Faster because of less drag from the tailwheel than nose wheel.??

Gary

Sound Logic. Especially assuming takeoff from a smooth surface. I say Steve's needs to complete one, and run the test

I'll probably get in trouble for this, as in open mouth insert foot, talking about what I know little about. That's seldom stopped me before, though, so some observations.

If this project is for the enjoyment of the owner builder/s, great.

If the hope is to develop a viable STC with the intent of making money commensurate with the considerable work, engineering, risk, and investment of time and money, . . . good luck. Maybe not so promising. I say this due to the current state of the economy and future outlook, near and mid-term. Plus, unless something drastically changes, the pilot demographic doesn't look all that promising either. So expect the doldrums to continue for quite a few years for GA, especially the piston side, before any rebound - - assuming it ever really does. Also, if someone has the bucks to invest upgrading their PA-28 to a low wing taildragger, seems they'd be money and performance ahead selling the Piper and buying something that's already a taildragger and more in tune with the mission. For backcountry flying, a high wing has obvious advantages.

BTW, I also own a low wing (87 Mooney 201) so I'm not prejudiced, though I often wish it were a taildragger. When that happens I fly the Husky

shortfielder wrote:My understanding has been that a 182 of same weight and horsepower as a 180 would take off shorter, probably fly slower, with each having propper rigging.

I figured the182 accelerated quicker because the tail was already in the air and could accelerate quicker. Then as it reached rotational speed, it could rotate farther because there was no tailwheel in the way,getting a higher AOA.

Faster because of less drag from the tailwheel than nose wheel.??

Gary

Your correct Gary. Comparing a '56 182 and a '56 180, the 182 hops off the ground a whopping 30 ft. sooner than a 180 and the 180 cruises 6 knots quicker than 182, according the Cessna's POH numbers.

Proof, that even the blind squirrel finds a nut

I always have like these http://dmaspeedmods.airweb.net/rockets.htm but for the money, a Vans RV seems the better choice.

DavidB. wrote:I always have like these http://dmaspeedmods.airweb.net/rockets.htm but for the money, a Vans RV seems the better choice.

Two of my best flying buddies own 150-horse yankee taildraggers. They're not quite up to RV-6 specs, but are a helluva fun machine-- short to take-off (landing, not so much), steep climbing, fast, and sporty handling. Cheaper than buying a completed RV-6, and quicker to buy & convert than building one from scratch. They cruise at 155+ (mph), and wind out to about 170 or so when firewalled.
One of them bought a 150-horse Yankee, and did the t/w conversion. Then several years later, the other one bought a stock yankee, then a year or so later did the t/w conversion, than another year or so went by & he did the engine upgrade. After getting the STC in hand & rounding up parts, the t/w & engine conversions each only took about a week.
Funny to see people look at them parked side by side (identical paint schemes except for trim color- one red, one blue), then watch them do a double take when they realize that they're not RV-6's.

Wow...stay away from the computer for one afternoon and all sorts of stuff pops up.....

I will try to respond to each one of you with questions from the first post on....

DavidB -- Probably not on takeoff performance. But when talking to the speed mod gurus, they say that the nose wheel is the biggest drag producer of any tricycle gear aircraft and converting it to a taildragger should give it a 10 to 20 MPH cruise increase.

behindpropellors and Zane -- Yes, it is a torque tube for tail wheel steering. But, it also incorporates collapsible pull handles for ground handling. The rudder cables hook to the short bell crank and the steering cables will hook to the longer ones. The rudder cables move a total of 3 inches and the tailwheel needs five. The 3D modeling makes it easy to figure out all my angles before I start to cut the metal to build.

OscarDeuce -- The airplane you are referring too was done on a one time STC. I talked to the fellow extensively about it when we first started this project because that was how we were going to do it in the beginning. Problem is this; The gears were swapped side to side, mounted on the front of the spar and canted forward 15 degree's. At that angle the struts do not want to work properly and it rides real stiff. You also have to keep the struts pumped up as high as they can go to keep the prop out of the dirt.

bumper -- You are right, if I calculated the time I have in this project there would be no way I would ever get my labor cost out of it. It is primarily for the enjoyment of the owner and myself in tackling the design of the thing.

Think of the PA-28 as the taildragging Vans RV-10...since the 10 kits are tricycle only, might as well make one out of a Cherokee for less.....

I love when people take on projects like this for the love of it all and not much else. Keep posting your progress. Do you plan on selling the parts to others? or is will you only sell in as an in shop thing? Probably to early for you to answer that?

David,

No not to early, we have decided that it would only be an in house conversion. Too much going on to PMA the parts and send off. will be a full blown multiple STC though...

Brian.

Taking a Maule MX7-180 taildragger compared to Maule MXT7-180 trigear, or M7-235 IO540 compared to MT7-235 IO540, whereas everything is identical except landing gear placement, speed difference is 5mph.