Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Engine thoughts for a Prather Toni

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Old 09-17-2004, 05:51 PM
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crashinmike
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Default Engine thoughts for a Prather Toni

Hi Guys,
I have a brand new in the box Prather Toni kit. I would love to see just how fast I can get this thing to go. I was doing some measuring and I have a NIB OS Max VRDF 65 that would fit if I move the firewall back 1.5" and run the exhaust down the side. I have a Hatori 610 pipe and I just ran the engine for 6 tanks a little rich on a cut down 12-8 to 10-8 . I then put on a Rev-Up 9-8 just to see what would happen and I stopped at 20,000 for fear the prop might let go.


OK hear is my question, what prop would I use on the is engine and has anyone tried one of these in a speed plane?

Thanks,

Crashin Mike
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Old 09-17-2004, 06:04 PM
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Al Valdman
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Default RE: Engine thoughts for a Prather Toni

Hi Mike,
I would suggest a 9x9 or 9x10 prop on that engine. Don't know if anyone remembers a company called R/C Kits, but they made a T-38 that was a bear to build but flew great. Anyway, a good buddy of mine had one with an OPS Super 60 and it went good, but just not fast enough. Then, he bought an OS 65 VRDF and ran it on a Mac Pipe. Well we never got a true speed on it BUT we timed it on about 20 passes and the average was 2.1 sec for 600 ft. It was haulin *&% . Back then we did not have carbon fiber and such and the wing failed just outside the retracts after a month of going flat out.



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Old 09-17-2004, 10:37 PM
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Default RE: Engine thoughts for a Prather Toni

You might have a bit of a weight problem with the .65, since with .40's you typically had to mount the servos at the rear of the compartment. Formula One's were also rather challenging to land, and will be more so with extra weight. I have seen a Tony fly well with a YS-45 RE and pipe, with speeds close to 140. In F1 trim, and 65% Nitro they would do about 165. The ST and Nelson 40's would use a Rev-up pylon prop cut down to about 8 to 8 1/4" diameter and pitched in the 7's with more pitch at the tips (close to 8" pitch). We would turn in the 22,000 rpm range, and unload to around 27,000 in the air. With the .65 the prop of 8 1/2 by 9 or 10 would be about right.

Or just send the kit to me.
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Old 09-18-2004, 09:30 AM
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Al Valdman
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Default RE: Engine thoughts for a Prather Toni

Hello,
He brings up a good point about the weight, it may be too heavy to fly well. I bet the new OS 46 ducted fan engine would make it go. You could probably run those APC black props then. I saw one of those OS engines on a Diamond Dust and they had it on the gun at 192. At that point they still did not have the pipe right. In your plane you should be able to get in the 150's

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Old 09-18-2004, 09:35 AM
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crashinmike
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Default RE: Engine thoughts for a Prather Toni

Thanks guys, you are both right, I think I will have to find another home for the OS65 VRDF engine. Any suggestions? Maybe one of the OLD go fast pattern ship in the 45 size. I have an MK Arrow 45. I also have a Southern R/C Bobcat.

Crashin Mike
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Old 01-17-2005, 08:28 PM
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PeterJayPriest
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Default RE: Engine thoughts for a Prather Toni

20,000 RPM isn't much for a 8 or 8 1/2 diameter wood prop. I used to fly F1 with Supertigre .40s (rear intake, rear exhaust) then the Nelson .40, 60% nitro, and we would tach on the ground 23,000 to maybe 24,000. The prop will probably cavitate before it lets loose a blade. Balance, obviously, is super critical at those revs.

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Old 01-18-2005, 10:28 AM
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Default RE: Engine thoughts for a Prather Toni

ORIGINAL: HighPlains

Or just send the kit to me.
Hey... you beat me to it

Just as a suggestion......if you do not have a noise problem where you fly, there are a number of "old" ST and Nelson F-1 engines out there. You might be able to aquire one - inexpensive. With just 15% nitro, you would have a hell of a bird on your hands.

As noted. weight is a HUGE concern on the Toni. It flys very well, but keep it on racing weight - or less. My first F-1 ship was a Prather Toni that I "over did" the glass work on the wings. Plane was 1/4 lb on the fat side. Landed like a brick, and I dared not put anything but a big radius on that first turn. The second one was on weight and flew great.

You can try the 65 in there....... but the weight and CG issue might bite ya.

Over the past few years, a number of folks have installed the Jett SJ-50 and Quickie-Jett engines in older F-1 aircraft to make sport/speed planes out of them. A few folks (older 1980's F1 pilots) noted that they were faster with the q-500 engine then anything the flew with the ST40 Most of the F-1s have pleanty of ground clearance for the 8.75" D1 series props, and the "big" props make takeoff a bit easier than with the 8" twigs.

Now.....
That Bobcat or little Arrow would be fun with the 65 up front!! At least you have a little wing area to play with
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