Wingspan: | 47 in |
Length: | 43.7 in |
Weight: | 3.3 lbs |
Servos: | 7-9 gram Servos Installed |
Radio: | Minimum 6 Channel |
Battery: | 4S 14.8V 2200mAh LiPo |
Motor: | Brushless 650 kV Outrunner |
ESC: | 50 Amp |
Prop: | 10.5x8.4 4-blade Prop |
Manufacturer: | Dynam |
Available From: | Bitgo Hobby or through your local hobby shop |
Street Price: | $219.99 |
The idea of putting a Spitfire on floats originated in April of 1940 as a response to the German invasion of Norway. A fighter plane that didn't need a fixed land base for operation was envisioned as the perfect fighter for this type of engagement. The Wolston Factory on the banks of the River Itchen undertook the task of fitting Blackburn Roc floats to a Mk1 Spitfire. Early model testing showed that the vertical stabilizer area was not sufficient to offset the side area of the floats and their mounting structure. A fixed sub fin was fitted below the rudder to improve directional stability. The invasion of Norway only lasted two months which shelved the Spitfire on floats project. The test Mk1 was returned to wheels and sent back to duty.
When Japan entered the War in early 1942, the need for a Spitfire on floats was rekindled. This time a Mk5 Spitfire was the test subject. It was fitted with a pair of 25 foot long floats and flew successfully on October 12, 1942.
A Spitfire on floats! What a great idea! One of the most beautiful iconic planes in the world fitted with floats. What more could an RC float plane enthusiast ask for? As great as the idea sounds, there doesn't seem to be an excess of models of this plane on the market today. Enter Dynam RC with their Supermarine Spitfire MK.VB. This model has been out a while, but Dynam RC only recently submitted one to RCGroups for a formal review.
Before we get too deep into the bowels of the review, let's understand some of the expectations for this model.
With that out of the way, let's open the box and get started.
My first impression was - It's a Spitfire on Floats! How cool is that! I can't wait to get this thing in the water.
Here's a list of the kit parts:
For this review, I supplied a Spektrum 14.8 Volt 2200mAh 30C 4S LiPo battery and a Spektrum AR637T receiver. I used my Spektrum iX12 transmitter for guidance.
The 1-page Illustrated Instruction sheet gave only very general assembly guidance. This level of instruction was typical for Dynam RC kit instructions. The sheet mentioned three types of glue - the glue, foam glue, and dry glue. The kit included three white tubes of what appeared to be foam/contact type glue and a small cylindrical tube of what appeared to be a CA type of glue.
Prior to beginning the assembly process, decals were attached to the surfaces of several parts. Placing the decals was much easier before the parts were assembled.
The first step was to install the pilot and canopy on the removable hatch assembly. However, when the battery hatch was removed from the fuselage, the retention magnet assembly came unglued from the fuselage. There didn't appear to be enough glue on the joint. The retention magnet assembly was epoxy glued back in place. As the fuselage was rotated, two large Lead weights fell out on the building table. Each piece weighed approximately 1-1/8 ounce.
Dynam RC was contacted and stated that there were 3 weights installed in the forward section of the Spitfire. They marked the located of the weights on the photo and said they would address the issue with their factory. They recommended that the loose weights should be installed back in the original locations. However, when the fuselage was examined, there was no third weight and there was no visible evidence of the weights ever having been installed in the forward part of the fuselage. Since that area of the fuselage was no longer accessible once the factory glued the fuselage halves together, the two weights were installed alongside the motor in the cowl area.
The pilot and canopy were installed on the battery hatch cover and set aside to dry. The next step in the assembly process was the installation of the elevator and rudder control horns. Each control horn was assembled with its respective pushrod attachment fixture. Note the orientation of the pushrod attachments. To minimized pushrod friction, the rudder attachment was installed above the control horn and the elevator attachment was installed on the outside of the control horn toward the tip of the elevator.
The included foam glue was used to fasten the control horns to the rudder and the elevator. Unfortunately the glue seemed to take forever to dry. After more than 6 hours, I gave up and went to bed. The glue was dry the next morning. The supplied foam glue was not used again for any other part of the build. Five-Minute epoxy glue was used for the rest of the build.
Once the control horn glue had completely dried, the rudder was placed in the slot in the elevator and the two pieces were slide part way into the rear of the fuselage. The elevator and rudder pushrods were installed through the control horn attachment holes before the rudder and elevator were fully seated on the fuselage. The two 2.3x20mm screws were used to attach the assembly to the fuselage. The control horn attachment set screws were temporarily tightened in place.
The instructions showed the installation of the propeller as the next step, but because of safety concerns, this step was left till the very end of the assembly process.
The next step was the construction of the float assembly. The bottom of each float was covered in a hard plastic material to protect the soft foam from damage, a very nice touch. However, the edges of the plastic overhung the edges of the foam by 1/8" to 1/4" in some places. A sanding drum and a rotary tool were used to trim off the excess material and even up the edges of the floats. This same trimming was needed on the excess canopy material that extended past the bottom of the battery hatch.
Next was the installation of the spreader rods into the floats. The rods were glued into one float and allowed to dry before they were glued into the second float. The two floats were then placed upside down on a table with the rudders overhanging the table edge until the second float glue joints had fully dried. While the spreader bars were drying, a light coat of waterproof grease was applied around the output shaft of the water rudder servo.
The float support brackets and their respective recesses in the floats were roughed up and some of the paint removed prior to the application of epoxy. The brackets could be installed on the floats backwards. The correct orientation placed the bracket mounting assemblies facing the fuselage and the water rudder servo facing outward on the right-side (starboard) float. Once the brackets were glued to the floats, the water rudder control rods were adjusted and mounted to the servo and the water rudders.
Next up were the wings. Unfortunately there were a couple of issues that needed attention before the wings could be mounted to the fuselage. The first problem was that the control horn on the left flap had come unglued. There didn't appear to be enough glue on the horn. The repair utilized epoxy glue to firmly secure the control horn. The next problem was the flap itself. When the flap was cut free from the wing at the factory, there wasn't enough material removed to give adequate clearance for the flap to move. A 1/16" slice of foam was removed from the root of the flap to give proper clearance.
It was helpful to mark each servo lead prior to mounting the wing. The wing spar pockets were deeper than half the length of the wing spar. The result was that the wing spar might have been inserted too deep into one of the wing halves. The center of the spar was marked and kept centered between the wing halves to ensure it was evenly inserted. The four wing mounting screws were only screwed in a couple of turns each to insure that all four were aligned properly before the wing was fully tightened in place.
The next step was to mount the float assembly to the bottom of the wings. The bracket mounting assemblies were screwed into the retract mounting blocks in the wings with four screws each. The water rudder servo lead was plugged into the servo extension lead under the right wing wheel well cover. The cover was secured with tiny spots of glue just in case.
While test fitting the flight battery into the battery compartment, it was noted that the motor shaft protruded into the battery compartment. Should the flight battery move forward in the battery compartment it could be damaged by the rotating motor shaft. A rubber spacer was fashioned and glued to the back of the firewall to keep the battery away from the motor shaft.
The next step was to check the motor rotation, calibrate the ESC to the transmitter throttle, and then program the throttle cut. Only after all these things were verified operational was the prop and spinner mounted to the motor.
The completed Dynam RC Spitfire weighed 3 lbs 12 ounces with the 2200mAh flight battery on board. The plane balanced perfectly at 3-1/8" (80mm) back from the leading edge of the wing with the battery all the way forward in the battery mounting area.
I set my Rates for each flight surface on 3-position switches and set them at 100%, 85%, and 70%. Since I like a little exponential, I set 20%, 15%, and 10% exponential respectively. The transmitter countdown timer was set for 5 minutes and set to start and run at any throttle setting above 25%.
The Dynam Spitfire needed some trimming to get it flying straight and level. Even with a proper trim, the Spitfire didn't feel "locked in" like I expected. It tended to wander a bit. This Dynam Spitfire may need the same sub fin addition that the full-scale needed. The rudder was very effective and felt a bit touchy even at low rates. The sub fin may also give a bit more directional stability and calm down the rudder.
Even with the rudder concerns, the Dynam Spitfire actually flew pretty nice. It was very well mannered at low speed and slowed down nicely with the flaps down.
The first landing showed another bad glue joint. The landing caused the right float support structure to come off the support mount. Close examination showed that there wasn't very much glue and that the paint had not been removed before the glue was applied resulting in a very weak connection.
The parts were epoxy glued back in place and the formal flight testing session was rescheduled.
During that first flight, something just didn't look right. There was something different about the wings. The right wing looked upswept at the tip while the left wing looked straight. Later when we got back to the shop, it was very obvious that the two wing halves were not exactly the same. The right wing had a definite upsweep toward the tip.
I'm not sure how the bend came to be in the right wing. Maybe the wing half was too tightly packed in the wing box and bent over time. There didn't appear a quick or easy way to straighten the right wing tip. In the air, the Dynam Spitfire didn't seem to notice the difference in wing geometry, so the flight testing was continued.
With the floats now firmly attached to the wings, the takeoffs tracked straight and the landings were nice and gentle. The water rudder linkage did take a bit of fine tuning to get them both set exactly straight with respect to the centerline of their individual float. Without this alignment, some takeoffs would tend to suddenly change course depending on which float left the water first. Slow speed water taxis needed high rate rudder control, but takeoffs worked better with low rate rudder.
The flaps worked well for slowing down the Spitfire for landings and definitely shortened the takeoff runs. The flap speed was set for 2 seconds and the Spitfire did not balloon when flaps were deployed. There wasn't any elevator compensation needed for takeoff or landing flaps
Dynam did a very good job with the motor/ESC/battery size power setup on this Spitfire. The Spitfire flew very well at 1/2 to 2/3 throttle. Full throttle was fun, but it wasn't really needed unless you just wanted to show off a bit. The Spitfire looked great cruising around the pattern and dropping in for touch-n-goes.
The Dynam Spitfire was capable of performing all the normal sport model maneuvers. Loops required holding the elevator throughout the loop including over the top rather than letting up - those big floats caused a bit of drag. Rolls were nice and straight. The rudder was very effective and needed to be carefully trimmed for straight flight or else the loops and rolls would wander. The biggest surprise was the violence of the snap rolls. Outside snaps resulted in an amazing tumbling spin. Luckily the recovery was straightforward and the basic stability of the Spitfire was very apparent.
Let's see, a scale-like Warbird on floats for a beginner? - NOPE. However, it would make a great scale style float plane for an intermediate pilot.
My buddy Jesse Webb was ready with the Camcorder and the Dynam Spitfire's floats were firmly attached for its second flight. I'm always amazed at Jesse's skills. He was able to keep up with this small plane while maintaining his balance on a narrow dock and not falling in the lake. I hope you enjoy his great work.
Dynam Spitfire on Floats - RCGroups Flight Video (10 min 28 sec) |
The Texas wind picked up a bit, but Jesse Webb had the Nikon at the ready and it was now time for some beauty shots. I hope you enjoy his pictures!
There is an excellent Thread on the Supermarine Spitfire MK.VB here on RCGroups. Member Spit n Pitts has recently offered up a drawing of a scale-style sub fin that should add even more stability to the Dynam Supermarine Spitfire.
It's a Spitfire and it's on floats! There were a number of issues with this build, but in the end, this is a really cool model of an unusual Warbird. If you understand that the build may be challenging in places and that this is not a perfect scale model, then you will be rewarded with a nice flying float plane that will be instantly recognized at any float fly.
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Last edited by Jason Cole; Mar 12, 2021 at 09:05 AM..
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Thanks Joe. Glad you liked the Review.
McD |
Latest blog entry: LEDs on my T-28
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If anyone interested in this plane would like to RC Geek it for a little more scale appearance, here’s a website with more pictures of a MkV based floatplane.
Spitfire Floatplane There’s Middle East variants in the same color as the model here. There is also a prototype variant with a bright yellow bottom. Since the graphics aren’t applied you can get what you need from Callie Graphics. There is also a good profile shot showing the sub fin. |
Last edited by GRW3; Mar 13, 2021 at 09:38 PM.
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That's great info George. Thanks for those links. I can second the use of Callie Graphics, they do wonderful work.
McD |
Latest blog entry: LEDs on my T-28
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Are you going to bring this to the River City RC float fly next month? I’m trying to get organized to do the repair and update work I need to do to take an Ace Seamaster (I bought at a local swap meet in 2019] so I have a reason to go. |
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Latest blog entry: Spektrum AS3X is Not an Autopilot
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Not sure yet. I plan to take it to SEFF next month, so I may have to put it in “protective custody” till then.
McD |
Latest blog entry: LEDs on my T-28
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Latest blog entry: LEDs on my T-28
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The supplied graphics are wrong. The decals are for a Mk IX that never saw floats.
The exhaust stubs are wrong, they are also for a Mk IX and this kit claims to be a Mk V. The color scheme is wrong for any of the floatplane prototypes. I have two of them and finished them correctly as well as adding sub-fins like the originals. Both of my starboard wings also show the upward bend around mid span mentioned in the review. That said, both of mine fly OK (I have around 3 years on each of them) but never have that completely locked in feeling that gives the greatest confidence, even though I have added a sub-fin on each of them. |
Last edited by kallend; Mar 16, 2021 at 11:41 AM.
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I live lakeside and honestly gave this Spit every chance to be a good airplane for water use. Didn’t happen simply because I broke more parts assembling it than I would have had I gotten to fly it. Imho this is the absolute worst arf I’ve ever had, between the wing warp, foam hinges and just generally P-poor quality of the design it never got its floats wet. I didn’t have any confidence in it after it was assembled and it has become a hanging queen.
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Latest blog entry: Greyhound Express
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Forgot to mention - the Detrum ESC on one of mine blew during run-up before flight #3, and caught fire, leaving scorch marks in the ESC compartment. Put a Hobbywing in there and no more trouble.
Although mine fly OK, I really wouldn't recommend to anyone except a die-hard Spit enthusiast who's willing to deal with a lot of hassle to get a unique model. |
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