There was just something "right" about putting the Saito Radial in my P-47.
Text, photos and video by Tom Hintz
Flight Video by -Clark Ponthier
Posted – 8-16-2016 Note: I want to say up front that the EME60 was not removed from my Top-Flite Giant Scale P47 Razorback for any performance reason. It has been super reliable, started easily and flew the Top-Flite Giant Scale P47 Razorback with authority. I like the EME 60 a lot and it will go in the next compatible airplane I get. The Saito 60cc Radial just sounds so realistic in a warbird and I hoped that its performance would match the needs of the Top-Flite Giant Scale P47 Razorback. I would find out on maiden day for this new combination that the Saito 60cc Radial was indeed up to the task.
When I crashed my RedwingRC 50cc YAK 55 with my prized Saito 60cc Radial on board the ensuing couple weeks weren’t pretty in my head. Forgetting the wing bolt that would in all likelihood would have prevented losing the RedwingRC 50cc YAK 55 if I had installed it was becoming a bigger deal the more I brooded about it. Plus, I hated having my best sounding engine in a box in the shop and that was not sitting well with me either.
Since realizing that the RedwingRC 50cc YAK 55 was too damaged to save I had been looking for an airframe to put the Saito 60cc Radial in but lacking a budget over $50 meant things were not looking good for my poor radial. Then I came across a YouTube video by a guy calling his channel “Knockoffs” showing his Top-Flite Giant Scale P47 Razorback making its maiden flight with the same Saito 60cc Radial I have in that box. I was inspired.
At 2:15am I was in the shop, putting my Extreme Flight Extra in the trailer and getting my Top-Flite Giant Scale P47 Razorback out of the other garage bay and onto the stand. By 3am I had the EME60 out of the warbird and plugged up its mounting bolt holes in the firewall. I dug out my Saito 60cc Radial mounting template and drilled the new holes in the firewall. An hour later I had the Saito 60cc Radial on the Top-Flite Giant Scale P47 Razorback and was working to find the right standoff length and it still wasn’t 3:30am yet. There are benefits to my insomnia.
As so often happens, there are small variances possible in how part of an ARF plane is assembled. It turned out that I had mounted the cowl on my Top-Flite Giant Scale P47 Razorback slightly different from the one shown on Knockoff’s channel. That variance meant that my stand offs had to be 35mm long rather than the 45mm Knockoff wound up using. I had the necessary hardware to make up the 35mm stand off so had the Saito 60cc Radial installed on the Top-Flite Giant Scale P47 Razorback firewall (in new mounting holes) in short order.
People told me this radial didn't have the
power to haul around the P-47. They
were wrong.
I did have to make up a new throttle linkage because the carburetor position was a bit different than with the EME 60. I had left the exhaust exit pipe at its full length on the Keleo ring exhaust and that turned out to be important because the oval shape of the Top-Flite Giant Scale P47 Razorback firewall area put the end of that pipe just a tick outside of the cowl and fuselage. Also, I had used a 24oz tank during the initial Top-Flite Giant Scale P47 Razorback build and that turned out to be way more than was needed. While installing the Saito 60cc Radial I replaced that tank with a 14oz RotoFlow tank. That fuel load proved to be more than sufficient for 8 to 10 minute flights while allowing my Top-Flite Giant Scale P47 Razorback to lose 10oz of fuel weight ahead of the CG point.
War birds are notoriously tail heavy but when I put my Top-Flite Giant Scale P47 Razorback now equipped with the Saito 60cc Radial on the EZ Balancer it nosed over forward with a clunk. I removed all of the lead ballast that I had installed when first building the Top-Flite Giant Scale P47 Razorback and while that helped, it was still nose heavy. A heavy, scale looking prop hub came with the Top-Flite Giant Scale P47 Razorback and when I removed that the plane balanced perfectly. I was running out of time if I wanted to fly the Top-Flite Giant Scale P47 Razorback the next day so left the prop hub off for the maiden flights on this combination. Later I will see if I can move the receiver batteries towards the rear to allow putting the aluminum hub back on the plane while keeping the CG neutral.
have to admit being a little concerned about whether the Saito 60cc Radial would have enough power to fly the Top-Flite Giant Scale P47 Razorback with the authority the EME 60 did. I used the same Xoar Military 23X8 prop that was on the EME 60 even though I have seen others use a 22X10 in the same military style prop. On the ground the Saito 60cc Radial with the 23X8 Xoar Military prop turned 6500RPM.
All of my concerns were proven unfounded when I gassed the Saito 60cc Radial and the Top-Flite Giant Scale P47 Razorback ran down the runway and lifted off. This plane always felt just a tick mushy when it lifted off but just give it its head for a couple seconds to accelerate and the controls get solid and responsive.
Throughout the flight the Top-Flite Giant Scale P47 Razorback seemed to be just as fast and stable as it was with the EME 60. The only time the Saito 60cc Radial lost significant RPM was in a near vertical climb but so did the EME 60. To me that loss of RPM is a function of the engine trying to haul 21lbs of airplane up a steep angle. One of my favorite things about flying the Top-Flite Giant Scale P47 Razorback is doing a falling turn that turns into a low, fast pass down the runway.
Now with the Saito 60cc Radial everybody else likes those passes as well because the Top-Flite Giant Scale P47 Razorback sounds far more realistic now. Those steep falling turns also tell me that the Saito 60cc Radial is reaching what sounds to be full RPM. I had intended on trying a Xoar 22X10 Military prop but the way the Saito 60cc Radial handles the larger 23X8 version I think I am going to leave it alone.
It is obvious to me that many of us in the RC community under estimate the power of the radials, particularly the Saito 60cc Radial. Hauling around a 21LB warbird with no indication of a strain should be enough evidence that the modern Saito 60cc Radial is making good power. It is also doing it on surprisingly little fuel. I run a 20:1 gas/oil (Redline Synthetic) mix and though I went from a 24oz tank to a 14oz version the Saito 60cc Radial only burns about 1/3rd of that tank in a very full 8-minute flight.
If you are thinking of a warbird, particularly if it is the Top-Flite Giant Scale P47 Razorback I would strongly suggest you check out the Saito 60cc Radial. Sure it’s not cheap but neither is starting with one engine and then giving in to your desires and putting another one in its place. There is just something about a radial in a warbird that seems right. And now my Top-Flite Giant Scale P47 Razorback is RIGHT!
See my original Top-Flite Giant Scale P47 Razorback Review – Click Here
See my original Saito 60cc Radial review – Click Here
Have a comment on this Review? – Email Me!
Knockoffs Top-Flite Giant Scale P47 Razorback with Saito 60cc Radial video - Click Here
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