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Jerry Bates P-51B Build "Hell Yes Let's Go!!!"

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Old 10-05-2016, 05:52 PM
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Default Jerry Bates P-51B Build "Hell Yes Let's Go!!!"

Well winter is coming and its time to start a build. Just received my 1/5 scale Jerry Bates P-51B plans and I'm starting to get my brain dialed in. it's been a few years since my last real build so hang on for the ride. The 12 year giant ARF storm has had me flying more and building less as for many of you I'm sure!

I decided to go ahead and order the FG fuse, canopies, both the Malcom and standard, belly scoop and chin cowl offered by Vic Catalasan at http://vicrc.com/ I got to meet with him at Warbirds over the Rockies a couple of weeks ago and he's really a great guy. Should have the parts in a few weeks. His glass work is awesome to say the least!

I'm always open to suggestions so if interested in participating in my build please chime in.

List of components for the build:

1.Jerry Bates Plans 2.Everything Vic has to offer as mentioned above 3. Probably going with a Bob Holman cut short kit (wing kit and fuse formers) I do have a cnc router however not sure if I feel like scanning and redrawing all the parts on my system. Still deciding.... 4. Sierra Mains not sure on the tail. Possibly elec... suggestions welcome. 5. DLE-55RA or sim up front. No side carb or side exhaust on this build. Will try to keep it all clean and hidden.

Jerry's Plans... Big, Beautiful, and very well drawn!


I will be posting pics as the build progresses. so check back often.
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Old 10-05-2016, 10:19 PM
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I like this. I have been converting the TF GS ARF to B model for about 10 years. The B model flies better than the D model. In all, I have built or owned 8 TF ARF and kit planes and recently have switched to the H 9 Mustang. The flying qualities of the H 9 Mustang are better all around than the TF plane but the H 9 plane has quality issues with the wing that make it hard to justify buying a third H 9 D model to convert to a B model. The fiber glass fuselage available for the Jerry Bates Mustang really looks nice. I will be watching your build and may just go ahead and order all of the parts and get started. I used the Robart pneumatics in both of my H 9 Mustangs and with a modification to get much more reliable main gear cycling, they work very well. You might want to try the tail wheel retract that Robart makes for the H 9 Mustang, it works properly out of the box and is scale, retracting forward like the full size.
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Old 10-06-2016, 07:22 AM
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Thanks for the mention of the H9 tail wheel. I'll take a look at it.

Here are a few pics from Vic's website showing his fuse: *This is not my build probably another customers.

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Old 10-06-2016, 03:18 PM
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I said the tail retract is scale but it has a heavy wire coil strut. It is mostly hidden by the tail gear doors so that doesn't bother me. I showed the pictures to my brother, who is going to start building his H 9 Mustang soon (if he can get the SpitFire off the bench) and he likes it too.
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Old 10-07-2016, 08:56 AM
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Here are some pics for motivation,

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Old 10-07-2016, 09:04 AM
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Signed on. You won't be disappointed with Vic's work. He's a real craftsman.

Bud Anderson's Old Crow is exactly the scheme I want to do Vic when I make room in the queue for a B model. Lovely...

Paul
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Old 10-07-2016, 05:47 PM
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The Crow was super cool indeed!. Col Bud Anderson did a special guest presentation a few weeks ago at Warbirds over the Rockies here in Denver. He also stayed at the field all day Saturday and did a book signing and watched the event. It was really awesome to hear him talk about the war and his history of flying at the banquette Saturday evening. I was able to get him to sign his book for me.
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Old 10-07-2016, 06:52 PM
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Originally Posted by sjhanc View Post
I said the tail retract is scale but it has a heavy wire coil strut. It is mostly hidden by the tail gear doors so that doesn't bother me. I showed the pictures to my brother, who is going to start building his H 9 Mustang soon (if he can get the SpitFire off the bench) and he likes it too.

Yeah, the function looks good but not to happy with the bent wire. the mechanics could be modified potentialy

Also just ordered the wood kit from Bob Holman tonight. hopefully can get started on the wing while waiting on the Fuse
The plans call for concealed aileron linkage using the RDS coupler and 1/8" hrdened wire with pocket. After tinkering around in the shop and not coming up with any better solution I decided to order the parts needed from IRF Machine Works http://www.irfmachineworks.com/

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Old 10-08-2016, 04:09 AM
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I am leery of using linkage with plastic parts in a large plane. My lifetime experience with plastic in critical locations like controls and surface attaching points is not good. In general, if it weighs more than 12 lbs. and can exceed 80 mph, it needs absolutely rigid metal or carbon reinforced parts in these critical locations. Unfortunately, these better products always cost more and most modelers vote with their wallets when they buy, so a lot of really good stuff goes out of production for lack of demand. Plastic is lighter and cheaper and works fine in small planes where aerodynamic loads are tiny. If you are going to use plastic in control linkage then you need to balance the movable surfaces both static and dynamically to prevent a catastrophic failure costing you a lot of time and money (balancing control surfaces can be difficult in RC models, it is always done with full scale A/C).

North American Aviation used plastics for over 50 parts in the Mustang, but they invented the plastic compounds in-house and developed the manufacturing process to insure safety-of-flight. The crash of the racing Mustang at the air race several years ago was at least partly caused by the failure of the plastic (phenolic resin) elevator trim tab that had been overstressed when one of the two trim tabs had been locked in a fixed position, transferring all of the trim loads to the opposite tab, which failed at around 500 mph. Pictures taken of the plane in flight before the failure clearly showed the entire tail boom structure aft of the cockpit twisted with wrinkled skin between the bulkheads. As the plane neared the critical VNE, the cause of the twisting force (the trim tab) was stressed beyond its ability and it failed, over-traveling and forcing a sudden full-up elevator condition. The extreme G force may have cause its pilot to blackout. At any rate he was unable to control the plane's flight and a terrible crash killing innocent spectators resulted.

I thought my own equipment choices, (based on years of success) were as good as need be, but after the loss of an almost new plane to a flap servo failure, I remembered several similar flap servo failures over 12 years and thought they might have a common fault linking them. After thinking about the problem for a while it occurred to me that my flap linkage geometry was the cause of the servo failures. Looking at the loads on the servos in flight I realised that my linkage installation was putting the servo under max load when the flap was fully deflected for landing, and prop blast was a major factor in the aerodynamic load fed back to the servo.

I had always installed my servo arms to go over-center at full UP flap, thinking this would prevent flutter at max speed. Aerodynamic loads at full up flap are minimal, just needing the air gaps to be small and no slop in the control links or servo gear-train (metal gear servos can have a lot of slop in the gears), and stiff surfaces. I changed the arm geometry to go almost over-center at full DOWN flap, removing all of the air loads from the gear-train and electronics (my servo failures had all been electronics failures). I buy servos in lots of ten, comparing gear slop and selecting the best for the controls and using the rest for throttle, TW steering, and air control valves.

I still had considerable slop in the linkage (horns flexing, servo case moving in its mounts, and even the mounts flexing under loads). I changed the servo arms to aluminum with 2 clamping screws in addition to the arm retaining screw, changed the offset ball-links on the rod ends to in-line clevices, reinforced the servo mounts, installed reinforced horns at the flap end, and finally changed the servos to very-high-torque digital-proportional mechanical landing gear servos.

The result is a flap control system that is rigid at all flap positions, and the loads on the flap servos decreases as it nears full travel and goes almost over-center. Only time (and lots of flights) will tell if this is the best control system but in analyzing the loads on the control system in both methods, I think my current solution is the most reliable. Having a flap servo fail and cost me around $1100-1200 in airframe and equipment costs, not to mention the time spent assembling it all I think is worth the cost of the 6 new servos, linkage, and labor to re-fit my three Giant scale warbirds. In past incidents I have had servo failures result in badly damaged wings and retract gear on out-of-shape landings and may have cost me the entire $2500 airframe and equipment cost of a D model crash.

Last edited by sjhanc; 10-08-2016 at 04:16 AM.
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Old 10-08-2016, 12:40 PM
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I'm 100% with you on the plastic hub for the RDS, not a big fan. I plan on press fitting an aluminum sleeve over the hub to prevent any distortion or fatigue. I also saw that Reno crash you were referring to. The RDS system will only be installed on the ailerons on this plane. Not down playing the importance or need for reliability by any means however ailerons experience far less force than an elevator in normal scale type flying because each side helps the other out in a roll. Whether I actually use the system will depend on how well It performs on the bench. Function, geometry, strength.

These servo hubs may also be a good option to start with
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Old 10-08-2016, 05:39 PM
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From what I have read about them (no personal experience), they are easy to install and set up and with a tight gear train in the servo, have no slop. I agree with you on their use for the ailerons. The aileron's size in the warbirds in this scale are relatively small and don't need high power, they will probably work fine in this application. The huge flaps are a different matter, the largest, most powerful servos should be used and the stiffest linkage you can engineer is what you should install. My problem was that I grossly underestimated the aerodynamic forces on the flap and the linkage and it cost me dearly. I followed the manufacturer's recommendations for servo size and linkage installation, which turned out to be inadequate. Over the years, what appeared to be just random manufacturing defects led to some expensive failures. In every production run of a particular servo there will be some that are a little weaker but will generally work OK unless put under excessive strain. An earlier failure of a new flap servo that landed working OK, but was smoking, is what started me remembering past flap servo failures, then the loss of a new plane to a flap servo failure got me to ground my air force and come up with an overkill fix. I also remembered a plane that had had an inflight flap servo failure that damaged the wing and retracts on landing, then had another flap servo fail a year later while taxiing out for takeoff. I lost one of my best B model Mustangs when it went into a sudden left snap roll when I hit the flap switch for landing and it screwed its way through the trees and dug a big crater. Total loss of everything but the DA 50r, which ran up a $300 bill for factory repairs. And I don't use salvaged flight radio systems in new planes.

I had reviewed the the GOV't report on the race plane's crash and I gave a closer look to some of the high resolution pictures published with it. I saw evidence of extreme upper wing skin buckling in both wings that I hadn't noticed before, probably because it was not mentioned in the report. This wing deformation was occurring during the high G snap roll that the plane went through before it started its final dive. I had noticed what appeared to be the same thing in my TF GS B model in high res. pictures a friend took of an aerobatic demo flight. After examining the plane carefully and bending and otherwise stress testing the model I concluded that what I saw in the pictures must have been the Monocote film wrinkling in the lift area of the wing. Now, about 50 flights later I am finding cracks in the fuselage in critical areas, so I have put it back in the shop for rebuild or a new fuselage.

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Old 10-08-2016, 06:43 PM
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Yes, P-51 Flaps are huge and generate lots of drag/load. the flap servos and linkages are located near the root of the wing and will be hidden under the fuse. The elevator linkages will be hidden in the fuse as well. Elev is split and controlled by two separate push rods/servos. I'll need hardened steel wire for the linkage bends for both flaps and elev to prevent any springiness. Rudder servo is ,mounted aft of the tail wheel in the rear of the fuse. It will pull-pull the tail wheel and rudder.
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Old 10-09-2016, 03:10 AM
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You may have a CG problem locating that servo in the tail. Remember, every extra ounce in the tail wil need 8-10 ounces in the nose just to maintain CG. I built 2 H 9 Mustangs with identical equipment, when the second plane was finished, the CG check was so far back it needed 1.5 lbs. hung from the engine's crankshaft behind the spinner to get the CG where it should be. Since that was not possible, it would have taken a lot more weight bolted to the firewall. It took a lot of work and some serious weight transfer to get the GC right. And I could not find any obvious reason for the tail to be that much heavier. The horizontal stabs from the previous plane were a few grams lighter so I used them after repairing them. I substituted lighter carbon rods for the steel hinge rods to save 1.5 oz.and moved the servos from the stabs to the fuel tank area. To avoid adding elevator control rod weight I used the last of my supply of Sullivan Carbon ny-rods (no longer in production). Then I had to leave off the Tail gear doors. It finally balanced in the middle of the recommended CG with out any nose weight, except for 2 large, heavy NiCad rec. batteries at the firewall. It was worth the extra effort- this plane flies better than any other Mustang I have had my hands on.
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Old 10-09-2016, 03:24 AM
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35 years ago I built 3 Byron F-16 and one F-86 models. They used a torque rod buried in the leading edge of the wing control surfaces that mated with a molded bellcrank in the fuse-wing root when the wings were bolted on. It was hidden, fairly simple and I never had any problems with it. I have never seen any other manufacturer use this method. Maybe it is patented, but patent rights have never stopped certain far east companies from copying what ever they wanted.
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Old 10-09-2016, 05:31 AM
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I believe i'll be ok with just the one servo in the tail. All other gas mustangs I've done required some weight in the tail. Unlike a FW 190 or Zero, Mustangs have quite a bit of nose over the LE of the wing which definitely helps out as well as the extra weight of gas motors/ignitions. I guess we'll see.
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Old 10-10-2016, 08:49 AM
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Just received word from Vic. My fuse is ready and is being shipped! That was super quick!

I'll post pics when it arrives
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Old 10-11-2016, 03:59 AM
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Subscribed.
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Old 10-11-2016, 03:56 PM
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I have ordered the P-51B plans from Jerry Bates. It took me a while to make up my mind whether to go with the A model Mustang instead of the B model, but the complex engine cooling problem of the A will have to wait a while longer.
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Old 10-13-2016, 01:58 PM
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Very nice, I thought about the A as well but I really love the B models. The A would be cool due to it's rarity however there are not too many schemes that really appeal to me. Are you planning on a FG fuse from Vic or are you gonna go full Comanche and build it all? I have also gone ahead and purchased what I hope will be enough balsa and ply to finish up the build from National Balsa. Basically all the long stock and some spare ply. The DLE 55RA is arriving today. Bob Holman short kit arrives tomorrow as well as the fuse from Vic. and what I really needed first will be here last. The dreaded retract purchase! I hate it but we need it! So getting ready to order it all.
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Old 10-13-2016, 02:40 PM
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Since I plan a full glass and paint finish I will go with the fiberglass fuselage, there is no way I could build a better looking fuse than Vic's product.
Having had a lot of prior experience with glass airframes and light weight cloth application I still have a considerable amount of resin and glass cloth on hand. During the time from my first TF GS P-51D ARF (2004) to now, I have only taken the time to build one all glass plane, a wood B model kit that took three years to get to test flight. It was destroyed the first day on the fifth flight when a servo failed hard over during the landing approach. I had used a ZDZ 80rv for power, an engine with a strong power pulse that shook every plane it had ever powered. I had always blamed the servo failure on engine pulse vibration but now I think it was possibly the result of a flap servo that couldn't take the air loads imposed by my old flap linkage installation (the factory recommended method). That plane had a 26-12 Zinger prop up front, and had incredible takeoff and landing performance not matched by any other engine size I have used since. I am sure that the 80 would easily turn a four blade prop if it just didn't shake the plane so much. I have a digital fish scale I use to get static thrust, it reads 50 lbs. max and the ZDZ would peg it with a 26-10 prop at less than full throttle and it pulled 45 lbs. with a 26-12 at full throttle.
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Old 10-13-2016, 02:55 PM
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I have an electric powered P-47 Razorback that is using the power system that I developed for the TF B model. It all worked great in the Mustang with wonderful top speed and unlimited vertical climb turning a Varioprop 22.6-18 four blade prop, but in the P-47 it is a disappointment. I am thinking I will use the electrics to power the fiberglass B model and buy a twin to power the Razorback. Airframe drag counts for a lot with electric power, more than you would think.
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Old 10-13-2016, 04:50 PM
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Interesting you mentioned the servo failure possibly due to engine vibration....I have a 33% Yak54 with the ZDZ80 RV which I've had for many years. I have 5645's on each elev surface which has always been plenty of torque and speed for that plane. about three weeks ago I had one of the elevator servos just quit while on the ground doing engine run ups. At low idle this motors shakes the crap out of the air frame and a buddy and I were discussing how violent it appears to be on the elevator surfaces when on the ground. Then the failure occurred days later, thankfully on the ground. That would have been a handful. It's hard to say if that was the exact cause. The servos have been in the plan for at least 6 years however not flying for several years. Age or vibration??? that is the question. The electric B model will be an awesome setup for power as always. I just cant stand the short flights and lack of sound on a warbird. However, you will really be able to nail down the scale appearance!.

My motor showed up:

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Old 10-13-2016, 07:00 PM
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In an effort to try to tame the ZDZ I bought a special ignition module from CH ignitions. Instead of the stock box which came with a 16 degree advance curve set by ZDZ at 20 degrees at idle and 36 degrees total above 2,000 rpm, he built me one that I could set initial timing at 0-6 degrees idle with a total advance of 28 degrees. It did not eliminate the power pulse at low rpm, but it did soften it a lot. The main reason these engines have such a powerful pulse is the compression ratio is about 1 point higher than all other model engines. If they had made the compression ratio any higher the engine would have been very difficult to start. As it was, it threw prop blades several times on starting by hand. On one occasion it flung a TF 26-10 blade at me, hitting my right hand and crushing 3 fingers. I never found the blade. When I flipped the prop it ran backwards about 3 turns, then reversed to forward and that is when the blade came off.

With the modified ignition and a Davis quiet pipe it actually made an almost civilized engine out of it. I also bought a Hyde mount for it, this mount isolated the engine so that no vibrations at all reached the airframe. The combo turned a 26-10 prop about 100-150 higher rpms than stock with only prop noise to hear. On a large prop that is a considerable power increase. The drawback with the soft mount was the engine rotated back and forth around the crankshaft. This constant movement broke exhaust pipes and their bolts, and shook the carbureter loose. I have thought that taking the cylinder to a machine shop and having the compression ratio lowered a little might help a lot. As it is I decided to put it aside until I get a 45-50 lb. airframe.
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Old 10-13-2016, 07:38 PM
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On the electric powered warbird there is no exhaust noise, but the airframe generates a considerable slipstream roar along with the prop rip of the larger props. I have a Benedini Merlin sound system that works ok and with 4 car stereo speakers the engine noise is very realistic at speeds below about 70 mph. If some one launches a chain saw motor it will drown out the Benedini sounds but they still can't catch the electric powered Mustang. I have a 20-30 mph speed advantage over IC powered models and nothing will touch it in a vertical climb so far, not even a couple of sport jets that tried. When I do a high speed low pass then pull it vertical it will just fly straight up until it is too hard to see. And the 4 blade prop is the fastest, and most efficent prop I have used. I usually do vertical rolls to slow it down some.
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Old 10-13-2016, 07:38 PM
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sjhanc
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Location: williston, FL
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The P-47 Razorback will do nice verticals with the electric power but the difference in airframe drag is too much to get the performance I get with the same power system in a P-51. When I took the electric P-51 to events they always ask me to do a solo demo flight during the noon display, by itself the engine noise can be heard at long distance. Another advantage is almost 100% power reliability once I worked out the ESC programming. You have to disable all of the default limits the ESC manufacturers program in to save the ESC from damage. In my case, the airframe is much more valuable than an ESC. I would rather smoke an ESC than lose a much larger investment in airframe and radio. The ESC that I use is much more than I need and it has its own cooling fan and separate cooling airflow.
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