Tower 40

Does the Tower 40 have the same run characteristics as the FP, specifically when used inverted?

I think I read somewhere that while the parts can be interchanged that the Tower motor may have a different case and as such can be used inverted. Did a search but can't find this info. Thanks in advance

John

Sorry...but I don't get this sudden FP's won't run inverted complex. I've run FP's in every possible configuration and unless there is a problem with the individual engine they all have functioned very well in any attitude they've been used in. I have over the years had a couple that wouldn't run very well in any confuguration but one had a bad crankcase (leaks) and the other had a very out of round sleeve.
One of the best running stunt configurations I've ever had was an FP40 in a 52 Nobler (that's an inverted set up) that I finished 6th at VSC 3 (or was it 4) with.
That airplane went home with Rusty Brown of Colorado and lived for many more years in Colorado and was passed to other flyers. It always ran very good.
One thing I do know about FP's is they like well balanced props and solid front ends and "hot" plugs. I've always used Enya #3's.
I also have a Tower 40 left over. I set up and sold quite a few of these, way back when, and they run very well also. The early ones had very tight crank bearings and required some lapping of the crank to run well and not seize.

I don't get it!!

Randy C

>Sorry...but I don't get this sudden FP's won't run inverted
>complex. I've run FP's in every possible configuration and
>unless there is a problem with the individual engine they all
>have functioned very well in any attitude they've been used
>in.

Per the SS engine information the 40 has a problem when inverted.

>Does the Tower 40 have the same run characteristics as the
>FP, specifically when used inverted?
>
>I think I read somewhere that while the parts can be
>interchanged that the Tower motor may have a different case
>and as such can be used inverted. Did a search but can't find
>this info. Thanks in advance
>
>John

The parts are interchangeable and the porting is identidal. The Tower 40 is an exact internal copy of the original FP but with true ABC construction. The only case differences are external and cosmetic.

I know in the R/C versions, the boost port is smaller on the Tower sleeve. I got less RPM when I swapped the Tower assy in my FP, but it seems to have a little more torque instead.

Tower 40--Much better run quality

>I know in the R/C versions, the boost port is smaller on the
>Tower sleeve. I got less RPM when I swapped the Tower assy in
>my FP, but it seems to have a little more torque instead.

I am not sure what you are measuring here, but I measure the sleeves of every engine I rework, and the sleeve porting on every engine I have measured between the Tower 40 and FP 40 were within thousandths of an inch of each other--well within the range of manufacturing error. Now I block the boost port so that becomes moot, but I still do not see any difference in the porting of their sleeves.

Now OS has a wide variety of deck heights from engine to engine. They work with + tolerances, not + or -. That way the deck height will never be lower than intended, but any tolerances will always cause the number to climb. (That means any errors will give you less compression than intended, and the piston will never hit the head). I have seen tolerance errors as great as 15 thousandths on deck height. That is like adding one head shim, by the way, and will also affect timing. The Tower sleeve is true ABC and I think of better quality (certainly better than some runs on the OS. Some of the middle runs were so bad I returned the engines). This could account for why some experienced better runs with the Tower engine piston/sleeve.

Thanks for the replies

I've always found this topic a little curious. There are certainly enough documented cases of the FP "burp" that Leonard described to accept this as absolute fact. I don't think there is a magic bullet like a certain prop - fuel combo that will cure it.

With this said there are also posts documenting that an 40 FP works inverted/upright without a burp. If we assume that these reports are factual to avoid having the discussion go on a tangent what could be the causing these few to work while most do not?

Also, is it possible to use something in the ports similar to what we do with the Fox35 to increase port velocity and get rid of the burp? If this has been documented I apologize, I searched and didn't find it.

Thanks in advance
John

>Thanks for the replies
>
>I've always found this topic a little curious. There are
>certainly enough documented cases of the FP "burp"
>that Leonard described to accept this as absolute fact. I
>don't think there is a magic bullet like a certain prop - fuel
>combo that will cure it.
>
>With this said there are also posts documenting that an 40 FP
>works inverted/upright without a burp. If we assume that
>these reports are factual to avoid having the discussion go on
>a tangent what could be the causing these few to work while
>most do not?
>
>Also, is it possible to use something in the ports similar to
>what we do with the Fox35 to increase port velocity and get
>rid of the burp? (snip)

The FP 35 and 40 cases are identical except for the number stamped on it. I have tried partially blocking the side ports in the case (after blocking the boost port completely) with no success. Maybe there is a solution on this that I didn't try. But the port cut into the sleeve is definitely wider than on the 35. Art Adamisin suggested using all synthetic oil in an 18 to 20% range, which I admit I did not try. As long as you don't go lean you may be OK. If you get a lean run with this (dirt in the needle, for instance) you could kill your engine. Running the engine in high rpm will probably help. For this you need a lower pitch prop. There are other things that people have tried that kill off some of the power, but the 35 worked so well without killing the power that I quit chasing my tail on it. It works fine as a side mounted engine, however.

Thanks Leonard. I may try the Tower 40 in the Nobler for laughs and grins.

I have run a side-mounted Tower 40 several hundred flights and have been very pleased with it. I am running a Fox 2 volt plug, Sig Champion 10% nitro, 20% 50/50 oil and a Supercool 11 x 5 prop. With other props, APC 11 x 5, for instance,there was a real wind-up problem.

Not familiar with supercool props. What is that?

http://www.supercoolprops.com/price_list2.php