The Big Beautiful Doll's ~Landing Gear~



UP-DATE 2/04/2013: I've finished my LG mod on the Big Beautiful Doll!

With the up-graded PZ-514s working in conjunction with the Micro Gear sequencer, my work on the BBD's LG is done!

P 51 BBD LG Test (0 min 58 sec)

UP-DATE 1/15/2013: I've U/L 3 videos showing how I up-grade both the PZ-514 & PZ-312 E-Tracts. I've also U/L some pics of my finished Landing Gear!


Much to my surprise FMS has installed the medium sized PZ-15090/PZ-312s in the V7.5 1400mm P-51! There's nothing wrong with the 312s, but I prefer the beefier PZ-15091/PZ-514s personally.

The struts are a nice touch. They're a working oleo 2-piece strut with an aluminum upper section housing the spring, and the lower steel section comprising of the spring compressor down to the wheel axle. The lower steel wired component is encased with a plastic housing along with the lower A-arm scissor. The upper scissor arm is also plastic and is clamped onto the upper section's base. For disassembly (I'll get into that later), you will need a PH0 phillips screw driver, as the A-arm assemblies are linked together with a very tiny phillips screw.

The tire/wheel combo is a vast improvement over those 2 3/4" slotted wheels we've seen on previous FMS planes. These new 3" wheels have a nice firm diamond tread rubber tire mounted on them, and the whole assembly is much more scale to the wheels we see on conventional warbirds. They even took the time to paint the inside of the wheels black to help offset the 8 spokes. The only drawback I can see are the C-clips used to hold the wheels on the axles. I guess time will tell if this works out?

Okay, now we turn our attention to these 312s. It seems there has already been a problem with the strut's 4mm pins. What FMS has done is drilled a grub relief instead of the usual flat ground reliefs for the struts 3mmX5mm grub screw. It's a nice idea, and really locks the strut in place. Unfortunately the reliefs are drilled to deep and has rendered the pins useless. There has already been complaints that the pins are breaking at that point. FMS has assured me they're aware of the problem and are addressing the issue.

Not waiting around to see what FMS comes up with, I thought I would tackle this little ditty myself.
These 312s come equipped with 4mm pins, and in my opinion they're to small to support the weight of this plane in the first place. Drilling a hole half way thru them just make matters worse! I decided I was going to use 5mm strut pins.
To do so two things need to be done. First, the 312 will have to be disassembled so I could drill a 5mm hole in the aluminum trunnion. IMO, that's the only safe way to do this procedure to keep from contaminating the interior section of the E-Tract with metal shavings. Second, the strut itself will also need to be disassembled for drilling. The reason, the upper aluminum strut shaft will need to be clamped in a vise to accomplish this procedure.

The following vids are an illustration of how I up-grade both the PZ-514 & PZ-312 E-Tracts with the aluminum trunnions, and how I go about drilling the PZ-312 4mm trunnions to 5mm.

PZ 514 Up Grade (8 min 21 sec)

FMS V7'5 P 51 Strut up grade (5 min 51 sec)

Drilling the PZ aluminum trunnions (2 min 25 sec)

Once I got everything drilled out using a #8 drill bit, and both the strut & 312 reassembled, I sat out to make the 5mm pins.
You could use 3/16" wire most commonly found in hdw, stores, but I like to use 5mm motor shafts due to their hardness. The pins need to be 27mm long for maximum depth in both the 312 and the strut, 9mm in the strut and 18mm in the trunnion. The FMS 4mm pin is 30mm long, but it will slide within the strut spring, the 5mm won't, therefore the 9mm depth. Before cutting the pins to length I clamped the 5mm motor shaft in the vise, and using a file, I marked both grub points (strut/trunnion) on one side. The trunnion relief is a shallow one as I don't finalize either of them until final wheel alignment. I liked the idea FMS has for the strut relief so I drilled a 1/8" indention, just enough to hold the grub screw in place. Because of the hardness of these motor shafts you will need a carbide bit. NOTE* because of the additional circumference of the 5mm pin I had to use a shorter grub screw (3mm x 4mm) so it would clear the flange.

Up-grading the LG from the PZ-312s to the PZ-514s!

Once I had my pins done, it was back to the BBD's wings. I still wasn't happy with using these 312s! Knowing the PZ-514s would slip in the wing pockets with the exception of a difference in depth between the pocket (22mm) and the 514 (25mm), I did a little exploring, and found that there was 5mm between the inner pocket and that plastic cover on the top of the wing. I'm sure both are glued together to give addition support to the E-Tract pocket.

Now knowing this, it was time for some plastic demolishion! With the help of my trusty hot knife and a few dremel tools I was able to remove the floor of the E-tract pocket, and still retain the integrity of the walls along with that piece on top of the wing. Once everything was cleaned up and smoothed out, the 514 slid right into place! Can you say "Happy Dance"!

The next step was making a 514 mounting flange to accommodate the four 312s mounting holes. You can modify the 514s flange to work, but I chose to use 1/16" aluminum. I've made several of these aluminum flanges in the past so I already had a couple made up. One other mod I needed to do, to complete the up-grade, was to make a new set of 5mm strut pins to compensate for the longer 514 trunnions. I ended up making the 514 pins 32mm long.

Once everything was bolted up and mounted in the wing it was time to check for clearances. Because the 514 trunnion stands higher then the 312 by 2mm some minor foam removal will need to be done in the wheel well to clear the tire.

After numerous cycles I was pleased with the performance! Now it's on to the other wing!

Other LG options for the 1400mm P-51D.

During the 514 mod I wanted to see what other options were available, so I test fitted the new FMS aluminum E-Tracts. If I could only convince FMS to modify the flange mounts to be compatible with the PZ's, they would be a perfect fit for this plane. I was also able to get the PZ-V2/716s in as well, but because of their 28mm deep I wasn't going to cut the flanges down just to see. I'm satisfied these 514s will work out fine!

I know some of this may be confusing, so check the thumbs for clarity.

Sandancer,

Nicely done! I will be using the 5mm mod to the 312 if the repair I just made doesn't work well. Thanks for taking the time to share it is appreciated.

Originally Posted by Jose5x5

Sandancer,

Nicely done! I will be using the 5mm mod to the 312 if the repair I just made doesn't work well. Thanks for taking the time to share it is appreciated.

Thanks to you as well for bringing the problem to both us and FMS's attention.

Thanks Sundancer, great instructional video. I've been afraid to take apart a working etrac, but your video has given me the knowledge and confidence to do it now. My 514s jamb up every once in a while and next time I have them off, I think I will disassemble them and clean & re-lube them. Thanks again.

What does the "PZ" stand for? Is that the mfg of the electric retracts? PZ-312, PZ-514's, are these the house units FMS installs?

Originally Posted by CrashMaster39

Thanks Sundancer, great instructional video. I've been afraid to take apart a working etrac, but your video has given me the knowledge and confidence to do it now. My 514s jamb up every once in a while and next time I have them off, I think I will disassemble them and clean & re-lube them. Thanks again.

I've taken some apart that didn't have any grease at all!

Originally Posted by sj3cub

What does the "PZ" stand for? Is that the mfg of the electric retracts? PZ-312, PZ-514's, are these the house units FMS installs?

Ping Zheng, is the company that makes 'em. After having issue with another brand FMS has decided to go with the PZ's now.

FMS is in the process of producing their own E-Tracts. I've got info on them on my "E-Tracts...The New Generation!" pg.

Excellent instructions!

I did something similar (drilling out the metal trunnions and aluminum struts for my P-38 to 4mm pins), and would highly recommend a drill press for drilling the trunnions. Use a smaller bit to align the trunnion's hole, clamp it down in one of these , then replace the bit and drill to size.

Even a cheapo Harbor Freight Drill press (something no workshop should be without) will do fine.

One other thing, are the PZ trunnions truly aluminum?
All of the "metal" trunnions I've seen (from Phillip at PW-RC, both the 514 and the "regular" size) are some kind of pot metal. Better than plastic IMO but definitely not aluminum.

cheers!

Originally Posted by Kurt

Excellent instructions!

I did something similar (drilling out the metal trunnions and aluminum struts for my P-38 to 4mm pins), and would highly recommend a drill press for drilling the trunnions. Use a smaller bit to align the trunnion's hole, clamp it down in one of these , then replace the bit and drill to size.

Even a cheapo Harbor Freight Drill press (something no workshop should be without) will do fine.

One other thing, are the PZ trunnions truly aluminum?
All of the "metal" trunnions I've seen (from Phillip at PW-RC, both the 514 and the "regular" size) are some kind of pot metal. Better than plastic IMO but definitely not aluminum.

cheers!

Heya Kurt, Thanks for the kudos!

When I'm performing a task with more critical tolerances I'll use a cross slide vise clamped to my drill press in the work shop. I realize a lot of folks don't have these kinds of tools at their disposal. That's why I tried to simplify this mod so anyone could do it in their kitchen if need be.

These trunnions are definitely cast aluminum. They only weight 0.8oz., and I agree with you, they are better then the plastic ones!

Gary

Where can one get the PZ retracts? I checked on their website and minimum order was 1000 pcs...
I would like to know where to be able to order all aluminium ones that would fit directly into my V8 (starting to wonder if this is correct though) FMS P51.
http://shop.lindinger.at/product_inf...cts_id=9701807
In the shop webpage it clearly states that it should be a V8 -
but in the kit there was no movable canopy , only one wing spar ( carbon) and motor was 4250 500Kv.

Anyhow - question remains ; where can I get the new retracts?

Originally Posted by Christofer H

Where can one get the PZ retracts? I checked on their website and minimum order was 1000 pcs...
I would like to know where to be able to order all aluminium ones that would fit directly into my V8 (starting to wonder if this is correct though) FMS P51.
http://shop.lindinger.at/product_inf...cts_id=9701807
In the shop webpage it clearly states that it should be a V8 -
but in the kit there was no movable canopy , only one wing spar ( carbon) and motor was 4250 500Kv.

Anyhow - question remains ; where can I get the new retracts?

FMS hasn't come out with a V8 yet. From the looks of the props on the P-51 posted on that link, that's the V6.

FMS has yet to release any news or info regarding their new aluminum E-Tracts!

Christofer H, Toysonics.com carry the PZ retracts in several sizes. They are very inexpensive and are of ok quality. They sell the PZ 18,32 and 54 gram units. I use the 18 gram metal trunnion units to replace the junk units that come in the Dynam foamys. The 32 gram units are the one's that FMS is installing in the Mustang.

Originally Posted by sj3cub

Christofer H, Toysonics.com carry the PZ retracts in several sizes. They are very inexpensive and are of ok quality. They sell the PZ 18,32 and 54 gram units. I use the 18 gram metal trunnion units to replace the junk units that come in the Dynam foamys. The 32 gram units are the one's that FMS is installing in the Mustang.

The 32 gram units are what are referred to as the PZ-312, the 54 gram is the PZ-514.

I just checked toysonics.com website. They show not FMS Electric Retracts.
Not even spare parts.

If your looking for them to be called FMS, then no you can't find them, but if you want the same units made by the same company that FMS uses to produce theirs, then they are on the Toysonic site. Exact same retract, produced by the same company. If you want the FMS label, then go to Motionrc.