OS25fp-s sold

Rusty, I didn't win this auction. I was wondering why it went for that price. Is it very desirable or rare?

coxaddict wrote:...Is it very desirable or rare?

Not in the least. I'd hope to catch a nice one or maybe even new for $50 bucks

I picked up 2 of those at swap meets last fall. One for 25.00, and the other for 40.00 ..... both have the Jim Lee venturi and OS Needle valve, and stock mufflers.

They are very powerful, especially with that larger Jim Lee venturi. I have one mounted on a Vampire with 62' lines, a 10x4 prop turning about 9700 rpm. 5 sec laps at beginning .... about 4.7 at the end, with standard tank and pressure. I'd like to tame it abit further ... maybe a piece of panty hose across the inlet.

Very nice engine .... but, me thinks, that e-bay price was alittle high

That muffler, (E2030) stock, on the OS 20 and 25 (FP or LA) engines is a "mild" tuned pipe for about 13600 to 13800 rpm on launch on the APC 9x4 or 10x4, a plastic clunk tank on muffler pressure with the stock venturi diameter and NVA. It runs pretty good. The fuel should be 5%-10% nitro with 20%-22% oil content.

Now, that venturi is not the stock venturi, as OS uses aluminum for all of them.

The tuned pipe effect will maintain RPM in the operating band as load changes. When the engine loads up it will tend to not sag, and as it unloads it will tend to depower to maintain RPM.

No idea why that engine sold so high, other than it is getting "rare" in the sense of it is no longer in production and people are hoarding them. (I have 3)

The FP comes in 2 types, iron cylinder, and ABN. With the higher oil load either will perform about the same. (my engines are all iron)

There is an essay on this with all the information on Stunt hanger by Brett Buck. ( I didn't find it quick, I'll look again )

Phil

http://stunthanger.com/smf/open-forum/skyray-35/msg291345/#msg291345
http://www.aeromaniacs.com/brett.htm
http://stunthanger.com/smf/engine-set-up-tips/fp-20-by-dan/msg6419/#msg6419

(I cant find the actual article though)
Phil

That is a ridiculous price. I find them at Swap Meets for $20 or less. Picked up one for $10 a couple years back.

Was there anything in the description that would allude to work being done on it?

Cribbs74 wrote:

Was there anything in the description that would allude to work being done on it?

Probably being that it was E-Bay ..... some people just can't help hitting that BID button. They just want it ... at whatever the cost to beat someone else. LOL

Personally, I very seldom place bids .... I look for BUY IT NOW sales. If I think it's fair, I buy it straight up.

Just last week, I did this with a NIB COX .049 Black Widow (replaces the Taipan Serpent on my Jumpin' Bean), and I got it for 57.00 and free shipping. I thought that was excellent, so I bought it ....

I got a Q , How do you now if its a ABN or Cast Iron just by looking ? And aren't mostly RC with throttle what you see or were there a lot of the CL versions out there .. I know the 10FP ones are hard to find CL . getback

getback wrote:I got a Q , How do you now if its a ABN or Cast Iron just by looking ? And aren't mostly RC with throttle what you see or were there a lot of the CL versions out there .. I know the 10FP ones are hard to find CL . getback

The case has a change in how it is molded between the two versions.

this is a side by side
http://stunthanger.com/smf/engine-set-up-tips/20fp-iron-vs-abn-cylinder/msg364861/#msg364861

I would say the one that sold was an iron cylinder when new.

Supposedly the ABN drops right in on a rebuild that can be changed. Changing a 20 to a 25 and back is also a possibility since the liners are sized identical on the outside and the stroke is the same (same crank)