CAR 4 and tailwheels

[Guest]

I recall that it had been stated in an earlier thread that airplanes certificated under CAR4 did not need an approved tail wheel since tail wheels were not approved under CAR 4.

I recall printing the CAR4 reg and now I can neither find the thread after searching nor find the papers that I printed.

Anyone have a better memory than me? Hope so.

Dave

[LostnSpace]

Re: CAR 4 and tailwheels

Over on the Lusacombe site, someone wrote that a FAA guy said that CAR was only for the manufacture, the owner or mechanic must use the TCDS/Specification?? nothing surprises me any more from the FSDO, gary

[PA1195]

Re: CAR 4 and tailwheels

I recall that it had been stated in an earlier thread that airplanes certificated under CAR4 did not need an approved tail wheel since tail wheels were not approved under CAR 4.

I recall printing the CAR4 reg and now I can neither find the thread after searching nor find the papers that I printed.

Anyone have a better memory than me? Hope so.

Dave

Can't help with finding what you did, but here's the discussion. See Post#26 for CAR4: http://vb.taylorcraft.org/showthread...293-Tcds-a-696

Gary in warm Alaska

[barnstmr]

Re: CAR 4 and tailwheels

Below are the CAR 4 regulations regarding tail wheels. The quote from the Luscombe site is wrong. CAR 4 is the original certification basis for the Taylorcraft B-series per TCDS A-696.. Major alterations must be substantiated to the original certification basis or later. Anyone with a question about certification basis should read the current revision of 14 CFR 21.101. Anyway, as you read below, the tailwheel itself need not be certificated. However the installation must be substantiated to the load bearing requirements shown.

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04.242 Three-point landing. The minimum limit load factor is specified in Fig. 04.10. The value of the sum of the static ground reactions shall be the gross weight of the airplane less chassis. The total load shall be divided between the chassis and tail skid or wheel in inverse proportion to the distances, measured parallel to the ground line, from the center of gravity of the airplane less chassis to the points of contact with the ground. The load on the chassis shall be divided equally between wheels. Loads shall be assumed to be perpendicular to the ground line in the three-point landing attitude, with all shock absorbers and tires deflected to the same degree as in level landing. The tail wheel or skid installation shall also be investigated for this condition. The minimum ultimate factor of safety shall be 1.5.

04.2420 Energy absorption. — The three-point landing condition specified in § 04.242 shall be assumed to be produced by a free drop as specified under § 04.2411. This requires shock absorption by both main wheels and tail wheel (or skid). (See §§ 04.340 and 04.440.)

04.246 Side loads on tail wheel or skid. Suitable assumptions shall be made to cover side loads acting on tail skids or tail wheels which are not free to swivel or which can be locked or steered by the pilot.

04.442 Wheels. Main landing gear wheels shall be a of type or model certificated by the administrator in accordance with the provisions of Part 15 and shall not be subjected to static loads in excess of those for which they are certificated. Tail wheels may be of any type or model and are not certificated. Nose wheels are subject to special rulings to be made by the Administrator.

04.4421 For the purpose of these regulations a tail wheel is considered as one which supports the tail of a conventional airplane in the three-point landing attitude. A nose wheel is considered to be a wheel supporting the nose of the airplane when the two main wheels are located behind the center of gravity.

[PA1195]

Re: CAR 4 and tailwheels

Are there substantiative differences between CAR 4 (noted for BC series on the TCDS under Certification basis) and CAR 4a (noted for BF and BL series on theirs) referencing tailwheels? Is it a typo error on the TCDS?

Gary

[Guest]

Re: CAR 4 and tailwheels

Below are the CAR 4 regulations regarding tail wheels. The quote from the Luscombe site is wrong. CAR 4 is the original certification basis for the Taylorcraft B-series per TCDS A-696.. Major alterations must be substantiated to the original certification basis or later. Anyone with a question about certification basis should read the current revision of 14 CFR 21.101. Anyway, as you read below, the tailwheel itself need not be certificated. However the installation must be substantiated to the load bearing requirements shown.

--------------------------------


04.242 Three-point landing. The minimum limit load factor is specified in Fig. 04.10. The value of the sum of the static ground reactions shall be the gross weight of the airplane less chassis. The total load shall be divided between the chassis and tail skid or wheel in inverse proportion to the distances, measured parallel to the ground line, from the center of gravity of the airplane less chassis to the points of contact with the ground. The load on the chassis shall be divided equally between wheels. Loads shall be assumed to be perpendicular to the ground line in the three-point landing attitude, with all shock absorbers and tires deflected to the same degree as in level landing. The tail wheel or skid installation shall also be investigated for this condition. The minimum ultimate factor of safety shall be 1.5.

04.2420 Energy absorption. — The three-point landing condition specified in § 04.242 shall be assumed to be produced by a free drop as specified under § 04.2411. This requires shock absorption by both main wheels and tail wheel (or skid). (See §§ 04.340 and 04.440.)

04.246 Side loads on tail wheel or skid. Suitable assumptions shall be made to cover side loads acting on tail skids or tail wheels which are not free to swivel or which can be locked or steered by the pilot.

04.442 Wheels. Main landing gear wheels shall be a of type or model certificated by the administrator in accordance with the provisions of Part 15 and shall not be subjected to static loads in excess of those for which they are certificated. Tail wheels may be of any type or model and are not certificated. Nose wheels are subject to special rulings to be made by the Administrator.

04.4421 For the purpose of these regulations a tail wheel is considered as one which supports the tail of a conventional airplane in the three-point landing attitude. A nose wheel is considered to be a wheel supporting the nose of the airplane when the two main wheels are located behind the center of gravity.

Hi Terry,

Thanks for that info. I thought that it was you that ah originally stated this.

How does one go about substantiating the load capability? Is that something that is stated in the tail wheel's description or specification?

I got into this subject because a friend has a J3 C65 with a Scott 3-24 on it that is really worn so I gave him a 3-24 that I had overhauled.

As he looks into his plane's TCDS he notices that a Scott 3-24 is not listed on the TCDS so we are scratching our heads about what to do next.

Is this something that a DER can resolve easily?

Dave

[barnstmr]

Re: CAR 4 and tailwheels

Dave,
It is a rather simple calculation of the ground reaction load for the maximum weight / hard landing condition. If there is a known load rating for the tailwheel, then we just need to verify it is rated above the calculated landing load with safety factor applied. If there is not a known load rating for the TW assembly, then some sort of drop test should be done. This can be a representative fixture rig with heavy weights and a simulated fuselage since we are not re-certifying the fuselage. Of course the geometry of the test rig should simulate the geometry of the fuselage. This test would only be assessing the tail wheel assembly.
Terry

[Guest]

Re: CAR 4 and tailwheels

Thanks Terry.

I found this and on page 4 it says that 3-24 has been approved for a J3 =>http://www.univair.com/content/Evolu...Tailwheels.pdf

Anyone know how to go about finding that approval and drawing?

Dave

p.s. apparently the Smithsonian has it in a box, see => http://airandspace.si.edu/Research/a...co_sec_48.html

About 1/4 down the page. How to get it??

[barnstmr]

Re: CAR 4 and tailwheels

The following link shows 3-24B approved for Stinson 108.

http://rgl.faa.gov/Regulatory_and_Gu...ight=tailwheel

[barnstmr]

Re: CAR 4 and tailwheels

And Piper PA-18 series here....

http://rgl.faa.gov/Regulatory_and_Gu...t=scott%202000

[PA1195]

Re: CAR 4 and tailwheels

......I got into this subject because a friend has a J3 C65 with a Scott 3-24 on it that is really worn so I gave him a 3-24 that I had overhauled.

As he looks into his plane's TCDS he notices that a Scott 3-24 is not listed on the TCDS so we are scratching our heads about what to do next.

Is this something that a DER can resolve easily?

Dave

Do the aircraft records reflect the initial installation?

Gary

[Guest]

Re: CAR 4 and tailwheels

Hi Gary,

No they do not.

Dave

[Guest]

Re: CAR 4 and tailwheels

Hi Terry,

Thanks for the info.

You gave me an idea.

I just put the 1999 RGL library CD in my PC and it is searching the entire CD for "3-24". I have later CDs but earlier seemed better to me.

Let us see what it finds.

Dave

p.s. Didn't work because I don't have the software to search the PMA or STC data base.

[PA1195]

Re: CAR 4 and tailwheels

Hi Gary,

No they do not.

Dave

Dave I assume the records include everything on file with the FAA...similar to recent discussions here regarding an original equipment list, W&B, etc.

Frankly I'd be surprised if it didn't have one installed given the age of the design and their popularity prior to the now common 3200 series. When the prices for the 3-24/2000 series exploded they went pretty much extinct as new items. Landes even used to put what I believe was that tailwheel on the rear of their wheel penetration skis to keep them from dragging on pavement. No way could they afford to do that today.

You probably have seen this discussion: http://www.j3-cub.com/forum/showthread.php?t=21406 It indicates the Cub Club may have a 337 to reference.

Edit: More discussion on said tailwheel http://www.j3-cub.com/forum/showthread.php?t=22599

Gary