New Twin well under way

[Dennis Adamisin]

AMEN, Unca Deano!


BTW. APC has now brought out the 9x4.5 as a PUSHER, they will be going on my PF twin.  Hope we can get APC to do pushers of the 10x5 and the 11x5.5 too.

Hope to lobby them next weekend at Toledo...

[John Cralley]

Dennis,

By all means put on the hard sell for an APC 11x5.5 thin E pusher. That would be perfect for my electric Ringmasters and I would not have to cut down those 12x6 pushers!!

John

[wwwarbird]

 What's the latest Bob???

[Paul Walker]

 

Attached are a couple of photos of a model sporting the most elegant paint scheme ever devised.   Of course, Billy Werwage doesn't see it that way...

Later - Bob


Yes, we know.  The ole BD paint scheme. 

Did you buy a 55 gallon drum of that bronze paint Bob?   
I think Billy probably still has some of the Day-Glo pigment left that you could use! 

Hope it is ready for the Nats.

Paul W

[Bob Hunt]

Hi Paul:

Nope, I don't have a 55 gallon drum of the bronze/copper... I have several! No chance that I'll run out of that paint anytime soon. I know that will make everyone reading this very happy. 

As for the twin: I have had to put it on the back burner for a while. I don't want to rush it to completion and I don't have the time right now to invest in finishing it properly for this year's season. Watch for it next year, however.

I did get a chance to install the tail and the control hook-up. I also finished putting the formers in all the molded shells. It's close, but there is far too much to do to make it ready in the time I have available.

Later - Bob
 

[John Miller]

Excellent project Bob. I understand you flew Gordy's wet twin. Impressive isn't it? That plane has 640 sq inches, roughly nearly the same as your project. I believe that over the years, twins have been over built, over powered, and too large. Watching Paul W. fly his B-17 was an eye opener, and proved that multi engined models can be powered by engines smaller than most would consider.

I beleive that one of the advantages of twins, has to do with the smaller dia. prop, but because there are two of them, you still have a lot of prop diameter to do the job. The smaller dia. prop seems to have less moment to impart prop forces so the turns seem to be much better, but the area allows it to have the traction to pull the plane through.

Using a pair of .15's instead of a single .40 or .46 on what is basically the same plane, the Pathfinder, seems to show that propped correctly, great performance can be achieved with engines, and I'll presume, moters as well, 60 to 75% the size, (when added together) for the same design, running a single engine.

Dennis A. has built and is currently flying one of Gordy's twin Pathfinders on e-power. At first he was running larger engines, and bigger props, but recently has gone to something much closer to what Gordy is running. Smaller motors, turning 9" props. I believe he has reported that the plane flies extreemly well on the smaller motors and props. If my memory is correcct, it flies better on the latest set up.

Best of luck and success on your twin Bob. It really looks great, and i love the lines of your sketch. Impressive Master Bob.  

[Dennis Adamisin]

QUote from John M's post:
"I beleive that one of the advantages of twins, has to do with the smaller dia. prop, but because there are two of them, you still have a lot of prop diameter to do the job. The smaller dia. prop seems to have less moment to impart prop forces so the turns seem to be much better, but the area allows it to have the traction to pull the plane through."


John's assesment on twins is very accurate and it is based on his background with a numerous twins.  Electrics make the twins a LOT easier to handle too - opposite rotating props are just the icing on the cake! 

[Bob Hunt]

I just wanted to "bump" this part of the Second Wind development series to the present page so that anyone interested in the whole story can read it from the beginning.

Later - Bob Hunt

[Air Ministry .]

bin wondin , if the TRIM alters gear up / gear down , but if its straight up & late down , youd have to reprograme it to see if it was worse Gear Down .
Which would be counter productive in effect .

Good to see it DID go in the Nats .

indeed , the ' prop disc area ' Vs prop inirtia PLUS the Thrust over the Flaps gets it all going good .

[Bob Hunt]

Hi Matt:

When I first began this project I was wondering also if the gear up/down would alter the neutral. Turns out that on all three twins we've flown so far (the test bed, Buddy Wieder's Ryan's Twin, and the Second Wind) we cannot feel any difference in the handle setting with the gear retracted or extended. Common sense dictates that there must be a difference because of drag with the gear down, and lack thereof with the gear up, but I guess Buddy and I are just not sensitive enough to feel it.

I posted this somewhere in one of these twin threads before, but when we first flew the test bed twin we did a pattern without retracting the gear. When we charged the battery (a 4,000 mAh 4S 25C Hyperion pack) after that flight we put 2,400 mA back in. Then we flew a flight with the gear retracted and charged the battery. We put back in 1,800 mA. A 25% reduction in energy useage with the gear up!  Stands to reason that there should be a difference in feel at the handle with those numbers, but we just don't feel it.

Okay, having reported that, I can tell you that the overall performance of the model with the gear up is dramatically improved. Go figure...

Later - Bob Hunt

[Serge_Krauss]

Thanks for that information, Bob (and John). This is a very interesting and significant thread!

SK