Is a 10 in prop too much for an FP .25?

[Paul Taylor]

My SkyRay 35 has a FP 25 on it. I have a 9x5 and it seems a little slow and soft on 57ft lines. I am letting it go at 10500 RPM.
Will this engine swing a 10x6 MA prop?
And can I expect it to pull a little better?

Let the information super hi-way open up.

Thanks
Paul

[peabody]

Paul...try a 10X4 APC....

[Wynn Robins]

10 x 6 is a little too much load - as Peabody said - use a 10 x 4 APC - they work great on the 25s.

[Steve Helmick]

The 10-4 TF Power Point shows good potential, too. I was running one on my .25LA today in place of the APC, on a kit built Skyray (heavy). I like the design, but I think a FS wing would help it a bunch.  Steve

PS: Dave Gardner runs an 11-4 on his .25FP on a Ukey...at Pat Johnston's urging, he says. It putts ok.

[Scott Hartford]

My vote goes to the Thunder Tiger 9x4.5

[Harleyman]

My SkyRay 35 has a FP 25 on it. I have a 9x5 and it seems a little slow and soft on 57ft lines. I am letting it go at 10500 RPM.
Will this engine swing a 10x6 MA prop?
And can I expect it to pull a little better?

Let the information super hi-way open up.

Thanks
Paul

If your prop inventory is a bit low and don't have some of the props suggested above, give the 10x 6 a try.  Just one flight.  It won't damage the engine, and then you will know what it does.  I feel it'll be a bit too fast with a 6 pitch.  But you may like it. 
 

[Mark Scarborough]

Keep in mind also, different brands of props react TOTALLY different even of the same size. I use an APC 10 x 4 on my LA 25 and on a FP as well, I use a MA 10 x 4 on my girls ringmaster as it isnt as critical and I dont want it to fly as fast. I am not a big fan of MA props as a general rule. For my money the APC props are far superior for about the same price.

[Steve Holt]

Your Skyray should not be slow or soft with a FP25 even on a 9X5 APC.  Mine was almost too fast with an FP25 and a 9X4 APC on 60' lines.  Lap times were just a bit over 4.5 sec.  If your engine is in good shape, it should turn that prop at 11K+ on the ground with 10% nitro fuel.  The suggestion of the 10X4 APC is a good one.  I switched from a 9X4 to a 10X4 to slow the airplane down a bit.  Instead, the airplane was even faster with the 10X4.  As mentioned, the Thunder Tiger 9X4.5 is also a very good prop on this engine.
Steve

[Jerry Eichten]

My son's Primary Force has a 25fp.  It likes the APC 10 -3, leaned out to the max.

[Arlan McKee]

Paul,
If I remember correctly, you switched to the MA 9 x 5 to try to tame down the power of the FP which was in your words, "screwing you into the ground" with the APC 9 x 4. I've been thinking that the new MA 10 x 5 3-blade, which is actually no more than a 10 x 4 (3 1/2 in the last 2 stations) would be a pretty good prop to try on the FP 25. Might cut a 1/4 inch off the tips...

[john e. holliday]

There has been some very good advice given so far.  But, as stated in the past alot depends on airplane, fuel and engine combinations.  I have several Skyrays that I fly.  One even has a four stroke.  Each one has a different prop.  Even those with with LA 25's.   The only FP 25 I have is mounted on a Sweet Sweep that was kitted by Walter Umland.  Started out with 9-5 power point.  Tried a power point 10-4.  Even tried an APC 10-4(was a dog).  Went back to the 9-5 as that is the one the plane is happiest with.  This is what really makes modelling fun for me is trying different things.  So try different props, but, don't change the fuel or airplane set-up.  Once you find the prop the plane is happy with then you can play.  Have fun,  DOC Holliday

[Bill Little]

My SkyRay 35 has a FP 25 on it. I have a 9x5 and it seems a little slow and soft on 57ft lines. I am letting it go at 10500 RPM.
Will this engine swing a 10x6 MA prop?
And can I expect it to pull a little better?

Let the information super hi-way open up.

Thanks
Paul

Hi Paul,

Something is wrong somewhere in the system!  A 9-5 APC (they are known to be very true in pitch) at 10,500 on 57' lines should be well under 5 sec. lap times! 

I used a 10-4 APC on a 25FP on 60' lines and launched at about that rpm and got 4.6 times.  This on a slightly overweight Tomahawk.

[Crist Rigotti]

Try an APC 11x4 and 15% nitro SIG Champion fuel.  Launch around 8800 rpm.

[captcurt]

The FP25 will be MUCH happier launching at about 11,400.  Try a 10x4 and clip it to about 9-1/4.

Curt

PS..Crist:  is that with a stock 25??  I really dislike the setups where the prop size and load has to keep the engine RPM under control.  JMHO.

Curt

[Crist Rigotti]

Blocked boost port.

[dave siegler]

My SkyRay 35 has a FP 25 on it. I have a 9x5 and it seems a little slow and soft on 57ft lines. I am letting it go at 10500 RPM.
Will this engine swing a 10x6 MA prop?
And can I expect it to pull a little better?

Let the information super hi-way open up.

Thanks
Paul

What is your lap time.... The RPM sound low, wind it up about 11.5K.  Also consider a 9x6.  APC's are a lot more efficient than MA try an APC.  MA's are great to slow down an airplane, they get used to keep combat planes below 80mph.  MA's seem flat in pitch IMHO, so  5 is more like a 4.

[Mark Scarborough]

A 9x6 at 11,500, are you really saying this? I run an APC 10 x 4 at about 103 and 58 foot lines, I get right at 5 sec laps.FWIW I think that if you use less than 10 inchs diam and steaper pitch what you are doing is letting the prop "slip" and using the inefficiency of the prop setup to control the speed. as Steve said, Dave Gardner is using 11x4 props very happily and if not mistaken its on 5 or 10 percent fuel. Diameter does work, pitch is speed control.

[SQ8s]

10x4 APC
56.5' lines
Sig Champion 10 with two oz of Castor added
4.8 laps
have fun

I run a Gator 10x4 prop
FP-25 Stock
on a Diamond back pipe 15" (AERO PRODUCTS)
59' lines
10800 RPM
4.8 laps
Sig Champion 10 with two oz of Castor added

[Steve Helmick]

APC also makes a 9.5 x 4.5, but it's not one of those you'll find hanging on the peg at LHS. I got one from Tower, I'm pretty sure, but can't find that size on their website now. It's not that hard to order direct from APC, tho. The 9.5 x 4.5 is one of those dagger type APC's, like the 10.5 x 4.5 and 12-5. Lighter than their usual "sport series" designs.  Steve

[john e. holliday]

Get the Tower Catalog as it has a lot of stuff not listed on their site.  Same way with the SIG and Brodak catalog.  Have fun,  DOC Holliday