Official FMS 1500mm P-47D Razorback Thread

[davegee]

Super! I just became aware of this company recently when researching linear servos online, which I don't know much about, but am learning. I think my biggest concern is that I have enough space in this relatively small airplane to mount the L12-R. I have the removable hatch/cockpit, and hope to mount the L12 behind the back wall where the pilot sits. I'll just have to play with it and figure a way to make it work. If done correctly, it looks like it would be a very smooth stroke pushing the canopy open and closed with the ability to set end points and rate of speed. Ian at Actuonix also told me that if the motor hits a stop, it won't get burned out or have a problem like that. When you reverse the switch, it simply returns back to where you command it.

They are working on shipping it to me now, so I'll be very happy when it shows up to go to work on it!

Cheers

davegee

[Elbee]

Precisely, I like their L12-Rs and will be using those on my F-14 project. Good choice.

[davegee]

davegee

Length of linear travel desired = 2.0”

Rotation of conventional servo in degrees = 120^o-160^o

Minimum radius of 360^o gear = 1.9”

Why?

Servo travel (example) = 120^o or 1/3 of 360^o

So through 120^o a round gear OD should measure 2” (6”=360^o)

For simplicity, cut a half circle or 180^o of the 6” gear in design

Circumference is p(r²) /2 where r=1.9”

Diameter = C/π = 6 / π = 6 / 3.14 = 1.90+ in

Design the rack longer by a a couple of teeth either way

Tooth size is whatever you decide, I choose 8 teeth per inch as I recall

There are gear STLs out there, I designed my own to see if I could

Yes, you could buy a linear servo with 2”+ travel, most are $70-$99 +/-

50mm travel = 2”+/- with various speeds

In any case, your canopy mounting/movement mechanism is the critical component

Best, LB

Thanks, Elbee! I got a design pretty similar to yours on Thingiverse. It uses a continuous movement servo, and I just tried it with my servo tester. I think it shows promise to hook it into my receiver I'll be using on a channel that uses a rotary knob or reversible switch to get it to work. I'm still working out the required linear distance for travel open and closed, but I think the 2 inch travel estimate is accurate.

I just had a phone conversation with Actuonix out of Canada. They make professional linear servos for all sorts of uses, and some are small enough to be used on model airplanes, like canopies, for instance. I ordered one small unit to play with. It uses a moveable square metal tube that you can adjust the travel right on your radio, I guess other modelers use these too. I thought it would be worth it to give this a try, Might be workable for other model projects, too, someday. We'll see where it goes.

Thanks for your excellent piece addressing these units. I think I'll eventually find something that will work.

Cheers

davegee

[Elbee]

davegee

Length of linear travel desired = 2.0”

Rotation of conventional servo in degrees = 120^o-160^o

Minimum radius of 360^o gear = 1.9”

Why?

Servo travel (example) = 120^o or 1/3 of 360^o

So through 120^o a round gear OD should measure 2” (6”=360^o)

For simplicity, cut a half circle or 180^o of the 6” gear in design

Circumference is p(r²) /2 where r=1.9”

Diameter = C/π = 6 / π = 6 / 3.14 = 1.90+ in

Design the rack longer by a a couple of teeth either way

Tooth size is whatever you decide, I choose 8 teeth per inch as I recall

There are gear STLs out there, I designed my own to see if I could

Yes, you could buy a linear servo with 2”+ travel, most are $70-$99 +/-

50mm travel = 2”+/- with various speeds

In any case, your canopy mounting/movement mechanism is the critical component

Best, LB

[davegee]

Man, that is looking great. Bob really makes the cockpit stand out. Going to be outstanding!
Best Regards, Rex

Thanks, Rex. Got the new continuous motion servo yesterday and will be experimenting with it and my printed canopy drive system to see if I can get it to work for me. As a backup, I'll be talking to the Canadian folks with their very professional linear servo that might just work for this, too. We'll see.

I don't remember if I told this story or not, but I read that when they first tried the powered canopies on the -25RE models, the windscreens were knocked clean off the airplane when they went to close the canopy! They eventually got it worked out!

Cheers

davegee

[vrosi1963]

Wow that looks very close , We will see very soon since i made contact today. since there is Minimal interest in this conversion as i figured , the pull run may be very small , maybe only 5 and i will be done. speak up quickly people

[jetfool]

Man, that is looking great. Bob really makes the cockpit stand out. Going to be outstanding!
Best Regards, Rex

[davegee]

James has been working hard on the plug for the canopy and has sent it to a small company to make some clear vacuform canopies for my Hairless Joe model. We're hopeful we'll get them to make these for us and send a couple to me, but I decided recently to look into backup alternatives if our primary canopies don't pan out for whatever reason. I decided to see if anyone else has a 1.5M P-47D bubbletop that maybe I could get a canopy from. Turns out, to my surprise there were at least two models. One is from Horizon and the other from Nexa, available from MRC.

I got a canopy from Horizon the other day, might work. Today, I received a fuselage and canopy attached to it from MRC which was an "open box" item and also ordered it, I think it was the last one in stock like that. I don't need the fuselage, but really need that canopy. It arrived today and it is almost perfect for my needs. I carefully cut the windscreen from the canopy and am positioning the parts how I want them to be fixed to the fuselage. The main plan is to still use the parts that James worked so hard on, but if that falls through from getting it vacuformed, I have a reliable and pretty accurate one from that one I bought from MRC.

I still hope to make the canopy powered from a servo, but we'll have to see how that goes. If nothing else, I'll have the canopy open using magnets and rails to let it manually open to show the details in the cockpit and pilot

Here's a few pics I just took. Just the very beginning of a new "sub" project!

[davegee]

Thanks. Your Lucky should fly very much like this one when you put it up in the air after the show. Really has a presence in the air for a foamie. I ordered three more of the E Flite bomb drop units that I’ll put in this one and two others so I can drop tanks from all of my jugs. I hope to do flight testing with at least one of my airplanes with this drop tank unit to see how it goes. Dan is working on the design for the 150 gallon “flat” tank that was used by several aircraft, especially P-47s. I’ll print up his V1 when he gets it done and we’ll go into flight testing with them. I think it shows promise, in theory. I already have experience with a 1/5 scale version I dropped in competition with FireBall almost 20 years ago.

[jetfool]

Davegee, Great pictures. Beautiful visual too
Best Regards, Rex

[davegee]

I took out one of my FMS P-47s, "Ole Cock" for a shakedown flight today, after having the winter off hanging in the garage. I found while testing it a few weeks ago, the motor had a "grind" to it in one spot as I manually turned the prop shaft. I decided to replace that motor with a brand new replacement that I bought. I have no idea what might have gotten damaged inside there. I don't recall any prop strikes using this larger, more scale V3 FMS Corsair prop, but I didn't want to take any chances.

I'll post a couple pics I took this morning after the flights. This has the printed scale Curtiss Electric prop and the printed cuffs (courtesy of Elbee's design) that I printed and glued onto the base of the props. It does make a slightly different noise, not sure if it is due to the prop cuffs on, but it flies great, about the same and the Hamilton Standard version without the cuffs that I have on three of my four FMS 1.5M P-47s, including the under development Hairless Joe version that I hope to fly this spring sometime.

[davegee]

still waiting for Park flyer plastics to confirm my plug has been signature received on April 1st UPS, very poor communication ,must be at the up coming Toledo rc show ?? end of the story ,will badger these people Monday after i got back from Kona yesterday for 7 days.

Thanks, Good luck!!

davegee

[vrosi1963]

still waiting for Park flyer plastics to confirm my plug has been signature received on April 1st UPS, very poor communication ,must be at the up coming Toledo rc show ?? end of the story ,will badger these people Monday after i got back from Kona yesterday for 7 days.

[davegee]

Sounds like a plan. A linear servo might be the best. I'm sure you will figure it out.

We will leave next Friday morning around 2:30-3';00 AM. about a 4-hour drive. We can set up at 7"00 am and be ready for the show at 9:00 am. A long day but saves one night from paying $180. CRAZY! That $180 dollar is better spent on a new plane, LOLI plan to take lots of pictures and hope to post some while at the show. Everything is ready to go and excitement is starting to build. Toledo always gives me a fresh start for spring flying. Many of the scale flyers go out to eat dinner at PACHO's restaurant in the evening, a great time had by all. Klinger from MASH talked about it on the show.
Best Regards, Rex

Sorry, I was off by a week! I bet you guys will have a great time, going to places like that restaurant in Toledo. I never actually made it into the town of Toledo. But I'm sure it has a rich heritage and culture of its own. Yeah, hotel prices are really sky high these days. We had to stay one night in Billings, MT this week. It was a decent hotel, but $150 for the night. You start thinking...what could I buy with $150! In any event, I'm envious of your upcoming weekend next week. It is a perfect kickoff to summer flying season!

I'm hoping that I'll come up with a solution for a powered canopy. We had one on Fire Ball that was very cool, but it was a lot bigger airplane and easier to figure out how to do it. Space is a real issue with this smaller foamie plane. At a minimum, I'll have a manually operable canopy for the time being, and if I figure it out, I can make a mod at that time to power it. I just don't want to waste a lot of time when I could finish it up and fly it, just waiting on one little, but cool mod to make it operate like the real thing. P-51s never had a powered canopy that I am aware of, it was a manual crank on the right sidewall to open/close them. We'll see.

Cheers

dave

[jetfool]

Sounds like a plan. A linear servo might be the best. I'm sure you will figure it out.

We will leave next Friday morning around 2:30-3';00 AM. about a 4-hour drive. We can set up at 7"00 am and be ready for the show at 9:00 am. A long day but saves one night from paying $180. CRAZY! That $180 dollar is better spent on a new plane, LOLI plan to take lots of pictures and hope to post some while at the show. Everything is ready to go and excitement is starting to build. Toledo always gives me a fresh start for spring flying. Many of the scale flyers go out to eat dinner at PACHO's restaurant in the evening, a great time had by all. Klinger from MASH talked about it on the show.
Best Regards, Rex

[davegee]

Davegee,
If your radio can't get the correct throw, you might try a fulcrum between servo and canopy to get the correct movement. A strip of 1/16 g-10 or 1/16" alum. by 1/4" wide would give enough strength. My .02 cents.
Looking forward to this.
Best Regards, Rex

Hi Rex: thanks, that might be a way to go. I'll attach a pic of the completed printed parts. The moving part works ok on the teeth of the servo, it's just the movement of that piece is only about 1/2 inch before the servo is maxed out in direction each way. If that servo could continuously move, I could get the amount of travel I am looking for. That would be great if I can figure that out somehow. I have ordered an inexpensive continuous movement servo to experiment with. My concerns are that I don't think it has or can put stop limits on it so it might be under load at each physical stop, held there mechanically and then overheat and burn out.

There is one other idea I am considering is a Canadian outfit that makes all sorts of linear servos for industrial uses, some very small that would be what I am looking for. They're gone through Monday for the Easter holiday, but I hope to call them up next week and see if they can recommend one that would work for me.

Are you in Toledo right now? Howz things looking for this year's show?? Please give us are report sometime if you have the time, or after the show is over.

Good Luck!

Dave

[jetfool]

Davegee,
If your radio can't get the correct throw, you might try a fulcrum between servo and canopy to get the correct movement. A strip of 1/16 g-10 or 1/16" alum. by 1/4" wide would give enough strength. My .02 cents.
Looking forward to this.
Best Regards, Rex

[davegee]

Hi All: I am working on a DYI servo-powered ratchet device to open and close the canopy on my P-47. I found something on Thingiverse and printed it up. It works ok in that it moves about 1/2 inch travel, but I need to get close to 2 inches of travel back and forth.

Is there some setting on my DX18 transmitter to get the throw longer each way approaching a 2 inch throw?

Thanks for any ideas or help on this! I think if I can get the throw long enough, I can figure out getting this canopy to open realistically, I hope!

Cheers

Davegee

[davegee]

Makes sense. Yeah I probably won’t be doing any more power tests . . . Another thing that I found is that the propeller wasn’t securely attached to the shaft… it still spun but I think not the same speed as the shaft. The friction probably caused the overheat and smoke.

thankfully it should be good now, I’ll try running it up to 20% power today and make sure it’s fine. Hopefully I don’t burn the house down!

Sounds good. You can always try any tests Outside!!😁😁😁

I have done a few full power tests that were just momentary runups and then back down again. For flying, remember that it is easier to get a prop strike on takeoff or landing if you get the nose too low during those times. Once you get used to the new prop, you can adjust a bit to avoid that.

Cheers

Davegee

[Eagle15]

I think the issue is more due to doing a static full throttle runups like that. In flight, the prop unloads a lot, particularly large diameter scale multiblade props. For example, you might see a peak of ~70A in flight at full throttle as the aircraft is accelerating or in a vertical climb. However static, that might be more like 110A. That's a good way to cook the motor and ESC if they aren't sized for that load.

Makes sense. Yeah I probably won’t be doing any more power tests . . . Another thing that I found is that the propeller wasn’t securely attached to the shaft… it still spun but I think not the same speed as the shaft. The friction probably caused the overheat and smoke.

thankfully it should be good now, I’ll try running it up to 20% power today and make sure it’s fine. Hopefully I don’t burn the house down!