Official FMS 1500mm P-47D Razorback Thread

[MrSmoothie]

"I really like those markings, MrSmoothie! Every part of the model is finished well, from the overall surfaces to the pilot, markings, and ordnance. I love how the stock FMS P-47 flies, but given all that you've already done to it, you might as well mod it for the larger prop, also."

Thanks A.M.!

I have decided to try the power upgrade. I've found a NIB FMS 5060 360kv and will have the 1700mm prop in hand tomorrow. Upgrading the ESC as well. I think it'll look better, and the few videos I've seen with the change were very impressive.

[prestonowtm]

Wow...one hell of a plane. Just got it together and ran it through the first flights. Seems a little on the slow side until you go to land or do a close fly by..floats onto the tarmac like a dream.

[Braden1274]

Hi, I am new to this and was wondering if anyone is using a Spektrum transmitter and if so what settings they are using for flaps and rates, Thanks

[tirolguy]

Hi guys

i want you to show my wonderful p 47 d razorback "TONY"

My favorite sheme on this plane

the last thing i must do is the weathering

regards from austria

Rob

[boomer108]

Very nice and Welcome to the Squawk tirolguy! The background is beautiful and so is the plane,it looks like a full scale P-47 sitting there.

[tirolguy]

Very nice and Welcome to the Squawk tirolguy! The background is beautiful and so is the plane,it looks like a full scale P-47 sitting there.

Thanks a lot.

Regards from Austria

Rob

[Dr. J]

This plane is a joy to fly. I'll be glad when they get some parts in since mine decided to take a nosedive into the ground.

[Pauly]

This plane is a joy to fly. I'll be glad when they get some parts in since mine decided to take a nosedive into the ground.

Dr J, don't you use a MR Sound board in that P47?

[DDawg]

I started building a Great Planes giant scale P-47 back in the day, but life and kids put that project on the back burner indefinitely. Until recently I had no Idea these big beautiful foam planes existed. I pulled the trigger on my P-47 today, I can't wait till it gets here!

[MrSmoothie]

I finally found my work bench cleared off (enough) to tackle the change-out to larger motor (FMS 5060 360kv) and the big FMS 17" prop. I am upgrading the ESC to 100A as well. The motor is installed and I got a new cowl so I could cut the "crankcase" opening to accommodate the larger motor diameter. Just finished painting that to match the "Big Squaw" color scheme. I wanted to save all the original parts in case I decide to return to the original setup.

F106deltadart's info came in handy and became more clear as I got into things. With this upgrade, you have to attach the X-mount to the firewall FIRST, and countersink the screw heads so they are flush. Then the motor is attached with screws from the INSIDE. To make that easier, I used hex socket head bolts and a 3mm "straight" hex screwdriver (not the "ball" head type). I had the motor on very quickly -- trying to do that with the short phillips head screws would have taken quite a while, I think, plus some degree of swearing.

Next, I have to assemble the plane and see where the 5000 mAh lip will need to be positioned for CG, taking the increased motor and prop weight into account. Doesn't look like any flying weather all week, so no particular rush.

Part of the reason for finally doing this? I have the new 1600mm F4U-1 Birdcage, and I dig the giant, near-scale prop! I always felt the prop on the Razorback was noticeably small. Of course, I'm hoping for some impressive vertical performance as well. I'll post updates as to how it works out (or doesn't).

Note that photo shows the stock prop...

[F106DeltaDart]

Great work, and glad my info was at least sort of helpful! Love the paint work on the front of the motor too, a nice touch. If the performance is anything like mine was, you will not be disappointed! What ESC are you using? I started out with a ZTW gecko, but had a bunch of issues with it, and found out it doesn’t play nice with that motor. Once I switched ESCs, it’s been a smooth ship!

[thisguy65]

How do you find the CG with the new motor?

[MrSmoothie]

Great work, and glad my info was at least sort of helpful! Love the paint work on the front of the motor too, a nice touch. If the performance is anything like mine was, you will not be disappointed! What ESC are you using? I started out with a ZTW gecko, but had a bunch of issues with it, and found out it doesn’t play nice with that motor. Once I switched ESCs, it’s been a smooth ship!

Thanks! Had you not already done it, I'm not sure I'd have figured out the ass-backwards way of mounting the motor (X-mount first, then motor, screwed from the inside).

With the plastic cut away from the dummy crankcase, a lot more motor was showing, so I painted the crankcase and motor front the same Model Master "euro gray" to help them blend visually.

'm using the Sky Power 100A SBEC 6A -- I've used many of these Sky Power ESC's which I buy from HeadsUpRC.com and had great luck with them. The prices might suggest they aren't very good quality, but I've found them to be solid and no failures so far.

How do you find the CG with the new motor?

If I understand your question correctly -- I just plan to place the 5000 lipo in the fuselage, back somewhat from the former position (against the firewall) until it balance at the correct CG. Once I determine that new position, I'll almost certainly need to make a new tray arrangement from the slide-in stock. F106, I recall you saying it had to go back a good bit -- how many inches from standard would you say? In other words, I'm not "finding the CG" as you put it -- only finding the new Lipo position to maintain the previous CG.

[F106DeltaDart]

If I understand your question correctly -- I just plan to place the 5000 lipo in the fuselage, back somewhat from the former position (against the firewall) until it balance at the correct CG. Once I determine that new position, I'll almost certainly need to make a new tray arrangement from the slide-in stock. F106, I recall you saying it had to go back a good bit -- how many inches from standard would you say? In other words, I'm not "finding the CG" as you put it -- only finding the new Lipo position to maintain the previous CG.

Not sure on exactly how many inches back. Since I’m running a different prop/motor combo now, it’s moved around. But, I did remove the movable battery tray completely, and laid velco from the front of the tray, up to the top of the angled battery compartment. If I remember right, the back of the battery (Roaring top 5800) was just sitting at the aft end of the angled battery bay. You could almost get it there on the tray, but there was interference with the canopy fitting.

[quitcherbitchen]

Pretty cool there Mr Smoothie. Can't wait for more photos.

[MrSmoothie]

Turns out that mounting the motor and modifying the cowl was the easy part of this upgrade. Figuring out how to mount the 5000 6s a few inches back proved to be more of a challenge. My first try was making a shelf from light "craft" 1/8" ply to extend the sloped plane of the battery compartment back a couple of inches, all the way to the plastic wing screw mount plate. I built a triangular-section box to go on the bottom, that fit into that space, to give the epoxy some attachment area. Finally, I added two velcro straps. I'd say this would probably work, but it just seemed a little "iffy" to me, and the straps proved to be harder to get to and attach than I had figured. Plan B: I cut the velcro straps off of the plywood base, and then took some 1/16" thick fiberglass sheet (I'm not sure what else to call this -- bought some in a surplus store years ago) and cut a new battery tray that would fit the existing rails, but be much longer to allow for the rearward battery placement. I cut two slots for the red velcro strap using a dremel and tiny round head bit. A Velcro strip was added to the top for the Lipo, but also to the bottom on the aft end -- this sticks to the added velcro on the top of the ply plate. After sliding the battery and tray in place, the back end of the tray is pressed firmly to the plywood's velcro to keep the tray from sliding out. This seems very secure to me, and takes some force to dislodge. Finally, I removed some foam from the forward-bottom of the hatch to provide some lipo clearance, if I have to slide it back at all for improved CG. I know, probably overkill on the whole deal, but I'm not flying today!

So I was wondering just how close to scale my new 17" prop is -- according to the Wiki article, the first P-47's had 146" dia. props. This model is 1/8.3 scale, so that works out to 17.5" diameter! Later D models had 156-158" dia. props! I did a very brief taxi up and down my driveway -- it took the barest amount of throttle to get it rolling. I can see there's not a whole lot of prop clearance, so I'll have to remember to hold some up-elevator on the takeoff roll. I have to admit, "Big Squaw" looks a whole lot more menacing with this prop.

[MrSmoothie]

These pics were taken just after the re-re-re-maiden (I've lost track) just after sunrise this morning. Takeoff was very smooth and uneventful (I was expecting torque or p-factor effects). It looked great in the air and the extra pull on vertical was terrific--but for the most part, I just cruised around admiring it. The only thing I noticed that was odd was that it seemed to be "dragging it's tail" in turn, like I needed to add rudder in turns, which I never noticed before. Landing was equally nice. I was very pleased, and did an aileron-rudder mix of 15% before the second flight.

Second flight started out fine, and did a couple of Immelmanns. Then I'm going straight and level, minding my own business, and watched the plane make a loud pop and more or less "explode", with one wing panel folding at the root and going straight in from 200 feet or so! Several of us watched it happen and it was actually kind of exciting. If you've ever seen the movie "Battle of Britain", there are some scenes where large RC models were used that had explosive charges -- looked kind of like that.

Four of us scoured the debris field, finding what was left of the airframe. We found 3 propeller blades. But after a good half-hour, we failed to find the prop hub, motor, motor mount,ESC, 5000 6s lipo and new battery tray! We were literally dumbfounded, as the terrain wasn't all that rough and we had no trouble finding small parts like chunks of the cowl, foam, or the prop blades.

Without the motor, etc., I feel like I'm investigating a crash without having located the "black box." But the most likely scenario is that one of the propeller blades failed, threw the motor out of balance, and then the front fuselage literally split apart on the seams, allowing the cylindrical motor mount to cleanly pull free. The left wing panel broke off immediately, just outboard of the two removable wing spars (this all happened in an instant). Did the remaining prop blade strike and sever the wing panel? Doesn't look like it. I suppose the other theory is that the wing failed and folded, and then the prop did its thing. Sure wish we had video to analyze.

The only undamaged parts: the entire right wing panel and cockpit hatch/canopy. Nary a scratch.

The funny part is that I don't feel nearly as bad as after some crashes, which typically involve "dumb thumbs". This just sort of happened; "not my fault". Ooops, other than not leaving well enough alone. Hey, it was a fun experiment while it lasted!

I know some guys have cautioned about these props and are even using $200 German props. But I figured since I was using the larger FMS motor and prop, that shouldn't be a problem. I'm sure I didn't ding the prop during either takeoff or the one landing.

[F106DeltaDart]

Dang! :Not-Talking: Sorry to hear that Smoothie, she was a beautiful machine! I unfortunately had a near identical experience, except mine lasted about 5 flights before exploding. The carnage sounds pretty familiar, although the wing is unusual. Hopefully all your foam chunks fit well enough for a rebuild. I similarly was never able to find the motor/ESC/Prop/firewall combo. Seemingly vanished into thin air.

[MrSmoothie]

Hopefully all your foam chunks fit well enough for a rebuild. I similarly was never able to find the motor/ESC/Prop/firewall combo. Seemingly vanished into thin air.

A rebuild of the broken stuff is out of the question (and I've rebuilt some pretty bad stuff -- in fact THIS "Big Squaw" is a rebuild of a previous crash when one aileron servo stopped working -- new fuselage and cowl). If the wing hadn't folded, I'm sure it would have been much different. So now I'm trying to decide if I should just "let it go", or try to rebuild -- again. I can buy a new fuselage, wings and stab for about $180. I have everything else (assuming I go back to the saved stock power setup). I'm not terribly crazy about doing the paint job for the third time! I'd probably do a different Jug from the same squadron instead of "Big Squaw" just to break the "curse." Having an intact cockpit/canopy is a big plus, as I spent many hours doing that part.

That's so weird that you couldn't find your motor, etc. either! I'm telling you, the four of us looked for some time and covered quite a radius from the eventual crash site. We didn't really like the idea of a mostly-charged 6s lipo remaining out in the scrub.

[F106DeltaDart]

A rebuild of the broken stuff is out of the question (and I've rebuilt some pretty bad stuff -- in fact THIS "Big Squaw" is a rebuild of a previous crash when one aileron servo stopped working -- new fuselage and cowl). If the wing hadn't folded, I'm sure it would have been much different. So now I'm trying to decide if I should just "let it go", or try to rebuild -- again. I can buy a new fuselage, wings and stab for about $180. I have everything else (assuming I go back to the saved stock power setup). I'm not terribly crazy about doing the paint job for the third time! I'd probably do a different Jug from the same squadron instead of "Big Squaw" just to break the "curse." Having an intact cockpit/canopy is a big plus, as I spent many hours doing that part.

That's so weird that you couldn't find your motor, etc. either! I'm telling you, the four of us looked for some time and covered quite a radius from the eventual crash site. We didn't really like the idea of a mostly-charged 6s lipo remaining out in the scrub.

Had a very similar search experience with a few of the club members helping look. Over a year later, it is still missing. Sorry to hear that the parts aren't salvageable, but I'm sure the next iteration will be even better! When I rebuilt mine, I took the opportunity to reinforce the firewall and move the motor back by using the FMS 1700mm firewall assembly and some home depot foam: https://www.hobbysquawk.com/forum/rc...4664#post84664. If you do reconsider on going back to a scale prop, I highly recommend it for motor fit if nothing else.