Profile Oriental Engine?

My buddy is building a Brodak Profile Oriental for sport flying and is pondering which engine to use. He would like to get a relatively long lap time as his reactions are not super quick. The finished plane will likely end up of typical weight: not super light, but not super heavy either.

Which motor should he use?

OS 25 LA?

As you likely already know, the Oriental has a 53.5 inch wingspan with 555 sq. in. area.

Thanks in advance,

Me thinks you're going to need a bit more power.....a Brodak .40, Magnum .36, LA .46 or one of Len's engines will do fine.

See Ya

LAST EDITED ON Aug-17-04 AT 10:04 PM (CDT)
 
>Me thinks you're going to need a bit more power.....a Brodak
>.40, Magnum .36, LA .46 or one of Len's engines will do
>fine.
>
>See Ya
>
>Peabody

What Peabody said!! or the LA 46 on longer lines will do the trick.

I'd go with the square finned Magnum XLS .36, with tongue, stock, or Mac's Muffler (use muffler to adjust CG). Probably would need to shorten the nose an inch or more, anyway. More power allows slower lap times. Adjust speed with prop pitch. Marginal power is a crash waiting to happen, and the profile Oriental typically weighs more than the full fuselage version. Steve

>Probably would need to shorten the nose an inch or more,

Because ??

Bigger engines weigh more.

The OS 25LA is a nice engine, but your friend would struggle to keep the lines tight in maneuvers. That's even worse than fast laps.

I used a 40LA on mine, 4 ounce tank, 10.5x4.5 APC prop, 61.5' lines. If you need slower, use longer lines.

The Oriental wing works great in a profile.

Ron King

I have just finished a Brodak Oriental with Brodak 40. Great engine but quite strong with 10x5 and fast laps on 62 foot lines sent off at 10,000 to 10,300. Up to 4.4 seconds per lap. Need to slow it down but I am very impressed with the performance. Pulls like a horse. Put 1.25 oz stick on weights on rudder. So shortening the nose is appropriate but that might be an issue in Classic. Suffice to say it flies just fine at 39 oz only need to trim it out for slower flight.

I agree with others that the 25 LA is too light.

Bob Smiley
a Lancair 360 builder/pilot trying to be a modeler

Tonigh I ran the plane, same setup as the previous message at 9,800 and 10,000 on the ground and had 5.1 sewcond laps with good results. I plan to reduce the venturi a smidgeon to improve fuel economy and reduce some power; that way I can up the revs a little more and hopefully get into the 4-2-4 break rather that the constant 4 cycle.

Bob Smiley

Bob,

Richard Oliver gave me a prop suggestion which worked very well on my Brodak 40. Take an APC 12-4 and trim it down to 11-4. Launch about 10K or so and enjoy. I got a great 4-2-4 break with the stock engine and it should slow your lap speed down a little. (Regular Oriental, 7.5 percent fuel, 62' lines).

If you want to try a lighter prop, I have also been using an 11-5 BYO prop cut down to 10.5 inches on 61 foot lines. I also tried a 12-5 Rev Up and cut it down to 10.5. The Rev Up has a great blade shape and the pitch runs true on all of the ones I have. Good results with either setup.

For the profiles, we have fallen in love with the APC 10.5-4.5 on 62.5 foot lines. Solid pull, 4.8 - 4.9 laps.

My two cents,

Ron King