Protect your passengers and yourself from accidental scalp injuries when walking under the wing!

3D Printed (Price Change due to shipping costs)

First, let’s talk about cost. A complete set of standard flap hinge covers printed in ABS, including mounting hardware, is priced at $60.00, shipping included (shipping costs $12.10 USPS). This set includes six covers: four standard covers and two for the outer hinge brackets, with three covers per wing, and the hardware to mount the covers.

These 3D-printed flap hinge covers are designed to fit all Stinson 108 models, regardless of the production year or presence of pre-drilled hinge holes. Unlike original aluminum covers, these do not rely on existing mounting holes. Instead, they snap securely into place and are attached using two MS35206-234 screws and two MS21044N06 elastic stop nuts, positioned beneath the flap hinge—eliminating the need for hinge mount holes. Each cover measures 1 3/8 inches wide by 6 1/2 inches long, with a complete set (including hardware) weighing 12.9 oz. Protect yourself from accidental scalp injuries when walking under the wing!

See the YouTube video on mounting instructions

You can access it here: https://youtu.be/uUnXKzZMyRM

Hinge covers with bolt hole covered.

Material Type

ABS

ABS (acrylonitrile butadiene styrene) is a widely used thermoplastic filament favored by professional printers for its stiffness and heat resistance. This 3D printing material is ideal for high-stress applications, such as those involving heat or impact. ABS is an excellent choice for those seeking an affordable, strong, and rigid plastic that can withstand external impacts, making it particularly suitable for components like flap hinge covers.

ABS is a great option for making hinge covers, as it can withstand temperatures between -4ºF to 176ºF. It’s Glass Transition Temperature (GTT) is 221ºF, GTT being the point at which ABS turns soft. Along with being heat resistant, it is also water-resistant and impact-resistant. I know it gets colder than -4ºF where I live, so I’ll have to wait until a cold winter day to test them. Also, a complete set of six covers printed in ABS weighs in at only 14 ounces.

UV is the enemy of ABS. I painted my set with the same two part epoxy I used on the airplane, then a top coat of UV protectant paint.

How Do They Mount to the Hinge?

Installing the covers is straight forward. The video below will show you how to do it, but in a nutshell:

• Snap on one hinge to the flap bracket
• Snap the other hinge to the flap bracket
• Using pliers or your hands, snap the two hinges together. You will hear a snap when they seat together.
• Install the two screws and nuts
• Tighten the screws, but don’t overtighten. Just enough to engage the plastic in the stop nut and have a thread showing through the nut.
• Operate your flaps through their entire travel envelop to ensure they do not bind.

Any Safety Concerns?

ABS is strong, but will break if overstressed. I’ve designed them with enough tolerance to allow the flap bracket plenty of room during operation.

Check the operation of your flaps prior to flight. Run them through their full range and watch for any issues.

Owner Produced Parts

The FAA provides guidance on Owner Produced Parts, and I want to summarize how I can make these parts for you so that you can install them as Owner Produced Parts.

One common question is whether the owner/operator must physically produce the part. The answer is clearly no. According to the FAA memorandum, “An owner would be considered a producer of a part if the owner participated in controlling the design, manufacture, or quality of the part.”

The memorandum outlines five scenarios in which an owner “participated” in the production of the part:

1. The owner provided the manufacturer with design or performance data necessary for the part’s manufacture. For example, this could occur if someone gives a manufacturer a part and requests a duplicate.
2. The owner supplied the manufacturer with materials for fabricating the part.
3. The owner shared fabrication processes or assembly methods to be used in the manufacturing of the part.
4. The owner provided quality control procedures (details can be found at the bottom of this page) to be applied during the manufacturing process.
5. The owner supervised the manufacturing of the part.

In this case, the second scenario is most applicable. You don’t need to purchase the material and send it to me; instead, you can simply specify the color you want, and I will handle the purchasing. A roll of quality ABS (Hatchbox) filament typically costs around $25.00 to $30.00 on Amazon, depending on the current market price.

To comply with the second item and ensure you receive the ABS printed covers, please let me know the color you would like for the prints.

Current Color Options

Although you can paint the covers, there are still several colors to choose from for the print. Search Amazon for Hatchbox ABS 1.75mm Filament.

Ordering

If you want to order a set, send me an E-mail to me, jeffrey892@gmail.com, and include the following:

• Color of Filament you request
• (Type of filament is ABS only at this time)

Payment

PayPal or Venmo are the best ways to pay. If you want to pay by check or cash, that’s fine, too. You’ll need to E-mail me to pay or to get my home address.

Ordering Options

1. ABS printed hinges are the only option at this time.

Specifics

Logbook Entry

Date:

N#:

Installed owner-produced parts consisting of six ABS flap hinge covers. Secured each cover using two MS35206-234 screws and two MS21044N06 elastic stop nuts. Performed a functional check of the flaps through their entire range with no issues noted.

The above described repair or maintenance is approved for return to service.

Signature:
[Your Name], [Your Certificate Number] [Certificate Type, e.g., A&P Mechanic]

‘Original’ Style Stinson Hinge Covers

………………………………….This style is not yet available for purchase…………………

If you have a Stinson with the mounting holes in the brackets, then you can use these covers that match the originals more closely. The photos below are hinges printed in draft mode, so the quality isn’t the best, but the final print will be higher quality. The original covers had threaded ends in one side of the hinge. Since these are plastic, my set has a elastic nut instead. I tried inserts, but I didn’t have much luck with them.

These take longer to print and I have not installed them on a Stinson at this time. If you want to be a tester for them, let me know and I’ll send you a set for free. Just send me an email at my address above.

Quality Control Process