Jetco Dolphin powered by a Brodak .25?

[frank mccune]

          Hello All:

          In my stash of "stuff" I have the above items.  How well would that combination work as a stunter?  Thoughts about the Dolphin? it sure is purty!

                                                                                                                           Tia,

                                                                                                                            Frank McCune

               

[Dave_Trible]

The Dolphin is a GREAT flying little airplane.  I built mine from an original Jetco kit and put the old Fox .35 open faced in it.  Very simple to build.  Keep it light and your .25 should pull it.  To keep weight down I replaced the kit sheet wood with contest wood and put very little finish on.  Just have to.  I think mine is 38 ounces.  If you use a .25 you be able to use the muffler.

Dave

[Ted Fancher]

David Fitz's dad Bill had a beautiful (monocoated that looked like a really good paint job) Dolphin powered by a Veco 19BB that he flew to great success in the old WAM (Western Associated Modelers) Class A stunt events.  We actually flew a lot of ".35 intended" stunters with that classy and powerful little engine including Gieseke Noblers and Sig Banshees and Twisters, etc.  These were almost all flown using four pitch wooden props of the era spinning at comparatively high and steady revs.

This far pre-dated the switch over by many to low pitch/high rev powertrains for our "pro" stunters as we weren't brilliant enough to realize how effective that set-up could turn out to be; convinced by all the previous generations of top fliers committed to the "classic" four/two/four break run that was as often a dismal failure for the average Joe as it was to be a successful.

Just recently pulled my old 1986 Nats champion Citation V off the wall that had been built for a four stroke Enya .46 but won the Nats with a good old ST .46.  It had been altered to a pipe operation and flown by a local flier that way for several years.  I cleaned it up and took it out with one of my old Randy AAC piston/liner OS .46VFs in it and flew a few flights to see if I still remembered how after a year or so of not flying.  Aside from stumbling around dizzy in the wingover and overheads I was thrilled at what a good airplane it was...until it flamed out in the first loop of the clover on every flight due to the small size of the tank (the nose was very short to account for the weight of the four stroke).  The prop was an old purple epoxy slightly undercambered Brian Eather three blade pitched to 3.4 launched in a rich two stroke.  Could be a contender if I could include a pit stop!

Ted

p.s.  The late and curmudgenly great Bob Baron was probably the only top competitor that utilized such an approach back in the "olden" days when he placed highly at (I believe) the 1966 or 7 Nats with his typically Bob "strange" Humbug powered by a (again, IIRC) Veco Lee 19 spinning a four pitch really fast.  Sort of a precursor to the Brett Buck tuned .20FP powered Skyray!

Sorry, TMI.

[wwwarbird]

 Like has been noted keep it real light and a good .25 should do fine.

 FWIW, my personal experience with the Brodak engines finds them to be on the low end of the power spectrum size for size compared with some other brands. I've ran a half-dozen different Brodak .40's, a .15 and an .049 and feel that they were all on the weak side. No experience with their .25 but I'd go with an O.S. instead.

[Clint Ormosen]

Like has been noted keep it real light and a good .25 should do fine.

 FWIW, my personal experience with the Brodak engines finds them to be on the low end of the power spectrum size for size compared with some other brands. I've ran a half-dozen different Brodak .40's, a .15 and an .049 and feel that they were all on the weak side. No experience with their .25 but I'd go with an O.S. instead.

Yeah, I agree that the Brodak 25 probably isn't up to the task. But, the LA25 should work well and that's the motor I'm going to use in the Dolphin.

But in one of the rare instances where Wayne and I disagree on something, I find the Brodak 40 to be quite powerful. (for a muffled 40 anyway).

[Brett Buck]

p.s.  The late and curmudgenly great Bob Baron was probably the only top competitor that utilized such an approach back in the "olden" days when he placed highly at (I believe) the 1966 or 7 Nats with his typically Bob "strange" Humbug powered by a (again, IIRC) Veco Lee 19 spinning a four pitch really fast.  Sort of a precursor to the Brett Buck tuned .20FP powered Skyray!

   
   Very much a precursor, but the example cases were Bill's Dolphin, and more so, Jim McClellan's Banshee/Veco 19. The breakthrough/whack upside the head was a gentleman that came out and flew with David and I with a kit Ringmaster with a full opaque finish, about 32-33 ounces, and an OS 15FP/8.5-5 Master Airscrew. The next weekend was the first Skyray 20FP flight.

     Brett

[wwwarbird]

But in one of the rare instances where Wayne and I disagree on something, I find the Brodak 40 to be quite powerful. (for a muffled 40 anyway).

 I guess to be fair have seen a couple good running Brodak .40's, just never had great luck with them myself. 

[Clint Ormosen]

I guess to be fair have seen a couple good running Brodak .40's, just never had great luck with them myself. 

That's because it's in the design. They're not compatible with Minnesota air. 

[wwwarbird]

That's because it's in the design. They're not compatible with Minnesota air. 

 Yeah, that must be it, there's usually a lot of hot air around our flying fields. 

[John Tate]

The OS 30 would be a great choice for power. Back in 2011 I did the CAD for the Dolphin, Decided to make it electric powered instead of glow. After 5 years of use there is still no oil soaking of the engine compartment. I was lucky enough to have the Dolphin to make the cover of Flying Models mag. Here is a picture of the Dolphin at Brodaks back in 2010. Photo by Elwyn Aud.