Disclaimer: I am not sponsored by Hobbyking but a long time user of many their products.

The following HK retracts are not full metal, inexpensive (<$10 per piece)

Great for planes ~ 1.5 kg flying weight

• Main gear. metal trunnion. I installed these into my GWS Zero (~800mm wingspan, <3 lb flying weight. Many brands seems adopting this type for their main gears, such as Eflite and FMS, best deal: Single unit without leg: https://hobbyking.com/en_us/electric...-trunnion.html or with leg
  https://hobbyking.com/en_us/servoles...en_us_products
• perhaps nylon trunnion: https://hobbyking.com/en_us/electric...1pc-18-8g.html
• 90 degree rotating (twist and turn) retracts. I used them in my GWS P-40 and Lanyu Corsair (~1 m wingspan, < 3 lb flying weight) https://hobbyking.com/en_us/twist-an...2pc-29-0g.html
• nose gear, nylon trunnion, the mounting pin seems a bit too soft: https://hobbyking.com/en_us/servoles...5mm-mount.html

X-flight sells twist-turn retracts with metal trunnion: http://x-flight.com.hk/index.php?p=6...11&cat1=8&dis=

For models ~2.5 kg flying weight (FMS 1400mm warbirds and 90mm EDF):

• Main gear: https://hobbyking.com/en_us/servoles...B&gclsrc=aw.ds
• This seems nylon trunnion, same dimension as the one above, slightly lighter: https://hobbyking.com/en_us/digital-...B&gclsrc=aw.ds
• Nose gear: https://hobbyking.com/en_us/servoles...5mm-mount.html
• Numerous inexpensive OLEO leg options: such as this https://hobbyking.com/en_us/alloy-ol...nting-pin.html

Larger models (46 size - 60 size, 8-12 lb models): 5 mm shaft

• Retract pin https://hobbyking.com/en_us/retract-...s-per-bag.html
• As the main they have the job done, the torque seems marginal, IMHO a little weak to handle some heavier oleo legs https://hobbyking.com/en_us/servoles...ount-2pcs.html
• Hard to believe the price: https://hobbyking.com/en_us/servoles...1mm-mount.html
• By the way FMS has some very beefy retracts for their line of warbirds (1400mm and above), better than the above but hefty price tag

Even bigger toys? I never own those following retracts, but tempting:

• Claimed for 22-25 lbs model. 5mm pin seems weak but they are not too expensive https://hobbyking.com/en_us/servoles...ount-2pcs.html
• The nose gear https://hobbyking.com/en_us/servoles...3mm-mount.html
• I would just drill out those trunnions to fit 6 mm pin, or even bigger ones: https://hobbyking.com/en_us/servoles...3mm-mount.html
• I would drill the hole in trunnion to fit 6mm Pin for the main gear: https://hobbyking.com/en_us/retract-...s-per-bag.html

FULL METAL Mucho retracts with very affordable price tag for >30 lb models[LIST][*]Looks like for 40 lb planes: https://hobbyking.com/en_us/all-meta...w-6mm-pin.html[*]8mm pin for nose gear, getting proper now: https://hobbyking.com/en_us/all-meta...s-10-12kg.html[*]There are a bunch of other similar with 80 degree rotations for warbirds, 12.7mm pin (sounds like 50' calibre antiaircraft mechinegun under this category, all looks awesome

Added per Lynxman's post:
For 20 lb model: https://hobbyking.com/en_us/all-meta...s-10-12kg.html
7kg class outward retract: https://hobbyking.com/en_us/turnigy-...-size-1pc.html

Video of my GWS Zero with the light weight HK main gear:

GWS Zero with Retract 3s 2200mah (2 min 27 sec)

I've had a NIB GWS Zero for a long time.
Your video is making me think about building it & using those retracts.
Don't know whether to thank you for posting the vid or not lol

The wing of Zero is still too thin, so I basically made a hole on the wing to accommodate the retract. Gorilla glue + masking tape is the secret for gluing and molding. After gluing in plywood mount for retract, I glue small piece of thin transparency film (used for projector demonstration, such as https://www.officedepot.com/a/produc...-Transparency/ ) to cover the top of wing. Then lightweight fiberglassed the wingtop.
Also make sure the retract leg has enough forward angle to avoid nose over. This Zero would have fairly small wheels, very prone to nose over on landing.
GWS Zero has been such a sweet flier for my past nine years.

I have these in my big 1:5,5 scale Macchi C-205. they have been flawless and precise, but I haven't flown more than a few times so far: https://hobbyking.com/en_us/all-meta...s-10-12kg.html

The MAcchi weighs 7 kg I think: https://static.rcgroups.net/forums/a...9-DSCN0569.JPG

I use these in my big 1:6,5 scale EL-39 jet. They work once built right, but they often arrive with the magnets installed incorrectly so they will stall agains the ends instead of stopping from magnetic pickup. They are also a bit sloppy, but haven't given me any problems since I installed them: https://hobbyking.com/en_us/turnigy-...-size-1pc.html

The plane weighs 8 kg: https://static.rcgroups.net/forums/a...3-EL-39-62.jpg

Thanks Lynxman sharing your experience! Just clicked some of the retracts we discussed and they were out of stock. Guess HK should give me some store credit promoting their retracts lol!

On the topic of HK retracts, I have made these retract mounting wells with my 3D printer and they're really great for getting the retracts mounted well into a foam model.

https://www.thingiverse.com/thing:2793303

https://www.thingiverse.com/thing:2793301

Originally Posted by Suko

On the topic of HK retracts, I have made these retract mounting wells with my 3D printer and they're really great for getting the retracts mounted well into a foam model.

https://www.thingiverse.com/thing:2793303

https://www.thingiverse.com/thing:2793301

Nice! Thanks Suko sharing your idea/file with the crowd!

I normally just use Dremel or file to grind the plywood mounting plate to fit those reversible electric retracts, then smear moistened Gorilla glue on the foam and plywood, and wrap the retract unit with saran wrap and place the protected unit on the plywood, cover with masking tape to wait until the glue foamed up and cure. Will have to make a youtube video to show the trick soon.

Just ran into this very solid 100 degree rotating retract with oleo leg, great for ~1.1 m wingspan or even bigger P-40 or Corsair:
https://hobbyking.com/en_us/turnigy-...B&gclsrc=aw.ds

It seems Eflite V1200 is using retract similar to one of the above:
https://hobbyking.com/en_us/servoles...ount-2pcs.html
Or the nylon trunnion: https://hobbyking.com/en_us/electric...1pc-18-8g.html

Some updates on the 1.5 kg class retracts. https://hobbyking.com/en_us/servoles...en_us_products

Due to their light weight (25 g without leg), they have been my favorite retracts for models lighter than 2 kg. Recently in the past one year, have installed them in 6s 70mm EDF jets (HSD 75mm J-10 and old HK Rafale), running on Hobbywing 60A ESC or Predator 70A ESC. One after another I started losing them, each just after just a couple of flights, simply stop working in the air. Total I have lost perhaps half a dozen such unit. No sure why.

Those similar units I installed many years earlier has been working fine for many years.

So will stay with the 2.5 kg class retracts with nylon trunnion, a little heavier but haven't burned any of them yet.

Maybe 6v burns them out where they live at 5v?

Joe: Heard about this from another pilot before...The BEC in Hobbywing skywalker 60 A is rated as 5 V. https://www.hobbywingdirect.com/prod...ant=3471324612

Predator 70A (red, commonly paired with FMS 1850kv 12b fan) has BEC rated as 5.5V: https://www.air-rc.com/assets/pdf/Super-Viper_562.pdf

Don't remember if I had tried running UBEC (mostly output at 5 V) to see if there is any difference, I would guess there is NO difference.

Same retracts installed in my Venom F-86 almost ten years ago have been working fine (I kept changing power system in her with different fans and ESC's, including the Skywalker and Predator).

Is there any fix?

Originally Posted by edwen303

Joe: Heard about this from another pilot before...The BEC in Hobbywing skywalker 60 A is rated as 5 V. https://www.hobbywingdirect.com/prod...ant=3471324612

Predator 70A (red, commonly paired with FMS 1850kv 12b fan) has BEC rated as 5.5V: https://www.air-rc.com/assets/pdf/Super-Viper_562.pdf

Don't remember if I had tried running UBEC (mostly output at 5 V) to see if there is any difference, I would guess there is NO difference.

Same retracts installed in my Venom F-86 almost ten years ago have been working fine (I kept changing power system in her with different fans and ESC's, including the Skywalker and Predator).

Is there any fix?

Depends on what quit. If it’s the motor, that is a possible replacement. If it’s the board, depends on what fried. It’s a crapshoot.

Eflite V1200 is using the exact same unit and there are reports all over that thread complaining about the failing of retracts: https://www.rcgroups.com/forums/show...-E-flite-V1200