I'm proud of my new Pentathlon! Just had 2 flights yesterday ahead of a cold front that is gonna make it unflyable here for a couple of days. Here are some photos of the bird.

This is a new power system for me. I've been electric for the last few years and decided to try "Gassifying" a pattern plane. This is the "proof of concept" bird and does it ever "prove the concept".

Power plant is an OS 160 modified with a walbro carb and using a ProSpark ignition system - Mueller header and aeroslave light pipe- standard length. With a APC 18.1X10 it is turning 7800 on the ground and has excellent power in the air. Running gasolineil at 16:1 I set a 14 minute time and had about 1/4 of the 12 oz tank to defuel. It's early to comment on reliability with only two flights on it, but I had good power, linear response and steady runs through both flights. Idle is very low and reliable- so low that I'm gonna have to put an ignition cut off on it to kill it.


Total all up weight is 4950g.

Thanks to Dean Funk for the vinyl masks and graphics!

George

What are you using for a motor mount? Are you using a nose ring? If so, how with the sensor?

Thanks George!

I can't wait to see the new bird and it sounds like you are happy with the gasser!

and thanks to Charlie Harper for the inspiration.

- Dean

Awesome George...Congratultions on the Maiden and making weight...!! Can't wait to see her fly. You gonna make it to Temple, Space City, etc....?

The RPM number on the 18.1x10 is very good.
Can you provide links as to where we can get info on the carb and ignition components? Any mods to the motor required to make this work?

Richard

Congratulations George! Well done.

When was the last time you flew a pattern plane for 14 minutes?...


-mark

Hi Richard!

I'm hoping to make it to most of the contests this season....I'll see you at Jim Sheffields later this month barring unforseen......

Here is a link to Nelson Hobbies which markets the prospark- there is quite a bit of information at this link:

http://www.nelsonhobby.com/prospark.html

As for mods, you can run the ignition system with the stock carburetor and run glow fuel and then all you would need to do is mount a magnet on the thrust washer and a sensor on the crankcase in front of the carburetor. (BTW this ignition system would work just as well with a 4 stroke running glow fuel.) The spark plug is 1/4-32 threads and just screws right in.

For the gas conversion, I also had to put a pressure tap in the crankcase for the Walbro carb and drill and tap the barrel of the Walbro carb for the mounting screws. I haven't changed anything else on the engine and Duarte (see below) says he's had long term success with the gas conversions with no problems running high oil content relative to most "gassers" at 16:1.


The ProSpark is made by Duarte Cabral and I think his main "target" is military RPV/UAV's but he's a very nice guy and I've spoken with him at length about this system. He recommended that I modify the walbro by putting a piece of brass tubing from the front plate of the carb curved over the top of the carb intake....just a little practice with the silver solder and it was a piece of cake<G>. I ran it on the bench without this mod and couldn't tell any difference, but it was easy enough to do that I did it on my "backup" as well. Duarte has been using this system for over 10 years, so I bow to his experience.


I am pushing him to incorporate an auxiliary channel cut off into the ignition so that you can plug it into an aux channel and remotely shut off the ignition. I have a switch on the fuse side but in case the carb sticks or a mechanical link breaks, I think it would be a nice feature.

I will probably put a "smart-fly" cut off on it in the meantime....just a little more weight to deal with<G>.

G

Hi Jon!

I'm using the Hyde mount designed for use without a nose ring. It gives less vibration damping but I thought I'd try it.....I could rig up a nosering if I have to, I don't think I'm gonna have to. It aint an electric, but this system isn't vibrating any more than my YS 140 did.

G

That's a really cool set up George! plane looks wild too!

if you're getting those kind of numbers off the 18.1x10 you're close to a YS 160 in top end power. I am curious as to the throttle response over time. Either way that's HUGE news for someone looking for alternatives! Hopefully you'll have it at the Crowley meet in May? I'm planning on being at that one to hang out with my D6 buds.

Put some gas through it and let us know!

-Mike

Thanks Mike,

Today, I started finishing my BMV3 for the same power system...I decided against using the ZDZ40 which is a full 10oz heavier than the OS160 conversion. It should be ready to go in a few weeks, too. I'll hopefully have both birds at the Crowley contest!


BTW, second OS 160 on the bench yesterday was turning 8K with the 18.1X10 APC! That was on the first run! I think it'll loosen up a little as it breaks in<G>

See ya there,

George

George,


Got any pictures of the OS 1.60 setup? What carb are you using? 8K on the bench could translate to about 83-8400 as it unloads.
I have run a Mejlik 19x10 on an OS 1.40 and it would tach about 75-7600. It had a very constant speed but needed just a little more punch in the wind.
I like the idea of running gas in a pattern plane. After running a gasser for the last year and recently getting back to the nitro(slimers) the gas planes do have their merits. The fuel economy alone would pay for the conversion.

Hope to see you at Dons clinic at the end of the month.

Wayne Galligan

Hi Wayne,

I'm planning to go to Sheffields barring any unforseen difficulties, so I'll see you there.

The gasser conversion runs a Walbro carb and since I didn't change any bearings , I'm using 16:1 oil mix.......puts out a pretty gooey black exhaust. That is the downside for me. I'm used to electric with no cleanup....but hey it's no worse than a nitro slimer.....
I'll attach some photos of the motor. The conversion is pretty straight forward:

Drill a hole in the thrust washer and press fit the magnet
Drill and tap a hole in the crankcase for the walbro pressure line
Drill and tap the walbro stem to hold it in the OS case
Mount the pickup sensor on the front of the crankcase.

Optional: Solder a tube on the front of the carb to extend the "neutral pressure port" to just over the carb intake....recommended by Duarte who has been doing this a while.

I've got another one on the test stand now...so if you wand any specific pic's let me know and I'll take them.

George

Very Kool!!! And a very nice job!


Bill Holsten

Advantage Hobby/Fliton RC/Duralite Batteries/ Guardian America.