Airplanes and Rockets' history & copyright Google search American Modeler Air Trails American Aircraft Modeler Young Men Hobbies Aviation Flying Aces Saturday Evening Post Boys' Life Hobby Distributors Amateur Astronomy Engines & Motors Balsa Densities Silkspan Covering Comics Electronics My Models Model Aircraft Articles Plans Model Boat Articles Plans Model Car Articles Plans Model Train Articles Plans 1941 Crosley 03CB Radio Model helicopter articles & plans Crosswords Model Rocket Articles Plans Restoration Projects Photos Peanuts Collection Model Aircraft Articles Plans Sitemap Homepage Hints and Kinks Amateur Radio Archives of the homepage R/C Modeler Electronics About Airpleans and Rockest, Disclaimer, Terms of Use Model Topics Please Donate to Airplanes and Rockets Parole Plaza, Annapolis, Maryland Hobby Items for Sale Airplanes and Rockets Hero Graphic


Drones - Airplanes and Rockets

Plastic Scale Model Kits - Airplanes and Rockets

DuBro Park Flyer Snow Skis on a Herr Engineering J-3 Cub

DuBro Park Flyer Snow Skis on a Herr Engineering J-3 Cub - Airplanes and Rockets

Herr Engineering J-3 Cub on DuBro Park Flyer Snow Skis 

DuBro Park Flyer Snow Skis Modification - Airplanes and Rockets 

Modification Pieces for DuBro Snow Skis 

DuBro Park Flyer Snow Skis Epoxied - Airplanes and Rockets 

Clamping everything in place while the epoxy dries assures alignment and flat ski bases. 

Snow season has arrived here in Erie, Pennsylvania, already (13" on November 10th), and I didn't want to miss the chance to do some flying off of snow skis. Last winter I mounted a pair of DuBro snow skis to my Herr Engineering J-3 Cub and flew a couple times with them, but they were the standard model that are too big and heavy for this 1/2A-sized model.

DuBro's Park Flyer Snow Skis seemed like they might be a better choice for the J-3, so I ordered a pair. The size is just about right, but the vacuum-formed plastic was a bit too thin for me to confidently install them on the J-3. I decided that they would be perfectly useable with a little sturdying up.

As can be seen in the photos, there are two stiffening slots molded into the skis, so I epoxied a 3/32" x 1/4" spruce stick into each slot. Up inside the landing gear mount area is hollow, so I shaped a piece of hard balsa block to fit, and then drilled through-holes to accept 3/32" inside diameter (I.D.) brass tubing to fit the J-3's landing gear wire.

The plastic was roughened with sandpaper in all contact areas, and then cleaned with isopropyl alcohol. After a trial fitting, 30-minute epoxy was applied to all surfaces, wood was installed, and then the skis were aligned (a short length of 3/32" music wire was inserted between them) and clamped to a piece of plywood to be certain that nothing would move and that the skis would remain flat while the epoxy set.

I also modified the manner in which the skis are mounted to the landing gear with the supplied wheel collars and springs. The instructions provided by DuBro are in an illustration format that is not exactly unambiguous. I figured out that the vertical bump molded into the ski mount area is meant to contact the long collar bolt and limit the upward angle of the ski while in the air. The spring puts force on the back of the ski which forces the front tip up when no weight is on the airplane. If that bolt is not adjusted properly, the tip can raise very high and would produce a lot of drag, and maybe even make the model unstable in the air. The tricky part is that the bolt serves two purposes - the aforementioned in-flight angle setting and it is the mount for the spring.

DuBro Snow Ski wheel collar mounting modification - Airplanes and Rockets

My modification was to place the wheel collar with the long bolt on the inside of the wheel and use it to adjust the in-flight angle, and then I replaced the hex set screw in the outside collar with another bolt that was just long enough for the spring to hook onto. That gave me separately adjustable spring tension and ski angle adjustment. The additional weight of a short bolt is negligible, and makes the entire process much simpler.

The DuBro snow skis got their trial run today, and performed great! they might have worked out fine in unmodified format, but I'm confident that they will outlast the J-3. Only 0.2 ounces was added to the original weight of 1.0 ounces.

 

 

Posted December 9, 2018

About Airplanes & Rockets 

Kirt Blattenberger, Webmaster - Airplanes and RocketsKirt Blattenberger

Carpe Diem! (Seize the Day!)

Even during the busiest times of my life I have endeavored to maintain some form of model building activity. This site has been created to help me chronicle my journey through a lifelong involvement in model aviation, which all began in Mayo, MD ...

Copyright  1996 - 2026

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the Airplanes and Rockets website are hereby acknowledged.

Webmaster:

Kirt Blattenberger

BSEE - KB3UON

Family Websites:

RF Cafe

Equine Kingdom

Model Aircraft Museum, AMA - Airplanes and Rockets

Rocket Kits + Accessories - Airplanes and Rockets

Plastic Scale Model Kits - Airplanes and Rockets

Academy of Model Aeronautics (AMA) - Airplanes and Rockets

Academy of Model Aeronautics

Tower Hobbies logo - Airplanes and Rockets

Tower Hobbies

Horizon Hobby logo - Airplanes and Rockets

Horizon Hobby

Sig Manufacturing - Airplanes and Rockets

Sig Mfg

Brodak Manufacturing - Airplanes and Rockets

Brodak Mfg