Sidewinder BBTU FP20?

[Andrew Tinsley]

Hello Folks,
               I have a Cougar (British stunter from the late 50s). This design features an upright engine. The version that I have, has a fiberglass body and the moulding doesn't let me convert to a sidewinder configuration, without a tremendous amount of butchery.
  My query is, can I use the FP 20 BBTU on an ABN motor with the usual advantages that I get with a Flitestreak? Dirty Dan seems adamant that it doesn't work with an upright motor! I can't for the life of me see why! However Dirty Dan is usually right!
  If this crafty plan won't work, then I have several iron FP 20s that I can use. If I run them 4-2-4, then I suspect that the power will be a bit marginal. Any suggestions as to running them at higher rpm with a reduced pitch prop, simply to get a little more power from the engine set up? Props, rpm ? Or should I run with an FP25 in 4-2-4?
  Lots of queries, anybody got any answers, life is too short to reinvent the wheel?!

Thanks,

Andrew Tinsley.

[Mark Scarborough]

Unless you insist on the 4-2-4 run, try the FP 25 with a 10x4 APC and set the needle so it is just at the crackle point, should be around 9800 or 10000. it runs more of a wet 2-2 mode.

[Steve Holt]

I have flown my OTS Feno quite a bit with an upright FP20 and it seemed to run just as well upright as it did sidewinder.  This might be unique to this particular engine, but it did run well.  I have since replaced it with a Brodak 25 to correct a balance issue and the performance is similar to what it was with the FP20.  I used a 9X4 prop on the FP and a 9X5 on the Brodak.  Both engines run a constant speed 2 cycle.  I use less than 1.75 oz fuel for the OTS pattern and just under 2 oz for the full pattern.
Steve

[Andrew Tinsley]

Steve,

Was your FP 20 set up for the BBTU tune up? That is with the E 2030 silencer and the de rigour plastic clunk tank?
I really like the tuned pipe style of run and I was hoping that I could emulate the same type of run as I get on my Flitestreak with all the Dirty Dan tweaks and exhortations!! (Not to mention an input by Brett!!!!!!!!)

Thanks,

Andrew.

[Andrew Tinsley]

Whoops!

My apologies Steve! If I had read your reply carefully, I should have noted that you say that your FP 20 ran in constant speed mode. So I assume that it was in BBTU mode!

Sorry,

Andrew.

[Steve Holt]

Andrew,
It had everything except the plastic clunk tank.  I used an RSM "old time" metal tank, uniflow without muffler pressure.  It worked just like the pressurized Hayes clunk tank did on the profile.
Steve

[Brett Buck]

Steve,

Was your FP 20 set up for the BBTU tune up? That is with the E 2030 silencer and the de rigour plastic clunk tank?
I really like the tuned pipe style of run and I was hoping that I could emulate the same type of run as I get on my Flitestreak with all the Dirty Dan tweaks and exhortations!! (Not to mention an input by Brett!!!!!!!!)

   I'd be happy to comment but I really don't know for sure how it runs upright/inverted. I have seen several that way that seemed to work just fine, but I haven't tried it myself.

    Brett