Brodak 25

[phil c]

Anyone tried running the B25 flat out?  What kind of props and rpms does it like?  such a nice, light little engine should make a good Speed Limint combat motor.

I don't have droves of obsolete F2D motors to use.

[Bob Reeves]

Hi Phill,

Haven't ran my 25 "flat out" but from the experience I have had it isn't a high reving engine.. I am running a 9-6 and getting just under 5 second laps on 60's in a rich two stroke. 420 sq inch fairly thick wing.  Although might be surprised what it would do with an 8-7, might even pull an 8-8 haven't tried it.

[john e. holliday]

I think the Brodak 25 is designed for stunt and sport just like its big brother the 40.  You would probably have to change the timing to make a combat engine out of it.  DOC Holliday

[Busby]

I think that it would probably be a good engine for speed limit, although the best we have found so far is a stock LA25.
Replace the remote needle valve with the older remote needle from OS, install a Master Airscrew 8x5,run 10%
Byron's Traditional and fly 7.0/ 7.1 laps<2 laps.>
Opening the venturi about .003 gets you right in the magic 6.9 secs per 2 laps.

[dave siegler]

Yes it works very well!

I used a borrowed one at SIG this year.  Brother Tom wanted someone to shake it out in a contest and offered to pit for me.  It ran well enough that he switched to it after I was eliminated. 

It is a little lighter than OS 25 but not as light as an F2d motor, so some tail weight may need to be added to an F2d airplane.   I liked the way it flew.  Tom felt it was a little nose heavy, but he is better than I am.

Contact Tom Siegler for the setup.  I seem to remember stock needle and venturi, and 8-4 or 5 MAS.  Becasue it was a new engine to us, we had a few issues with hot restarts and needle settings but by the end of the contest he had it figured out.  It didn't bog down at all, and running a little rich.

I think Tom would use it for SLC but has several non current F2d motors to use.  I inherated a few of his lightened OS 25's so that is what I will be using for a while.  It is a little pricey for me to stick in the dirt all the time.   

If you are using russian F2d airplanes the brodak 25 is a good chioce becasue it is lighter than most 25's

What about your low cost 15's?  How did the Magnum .15's work?  I have a new ASP 15 waiting for a venturi and needle. 

How about Norvel 25's?  gobs of power and nice and light.

Dave Siegler

[phil c]

Thanks Dave, exactly what I was looking for.
The Brodak appears to be about an ounce lighter than the Norvel 25(are they still available??) Brodak 160 gr., Norvel 189 gr.  LA 25 189 gr.

This is mostly a trimming issue, as you point out.  A lighter engine, if it has enough power, means less weight needed for trimming.  The stunt run timing also might make it a better running motor for combat, again, as long as it can pull the plane fast enough.

the LA 25 is hard to beat for a  $55 dollar motor.  Requires nothing but an adjustable venturi and a needle valve.

[dave siegler]

With an 8x4 we had no trouble making the speed limit, didn't have to lean it out too much.  Started out at an 8x6, had to go down to an 8x4 to meet the limit and keep the motor happy in the happy range.  It wasn't a stunt run by any means.  Only a little less power than a OS, but lighter so the airplane turned better I think.

 You may want to ditch the needle, it is a little coarse for a bladder, but it works.

I'd rather have a lighter 15 on an f2d airplane, becasue of the weight. 

Dave