150cc Pitts Python Looking for input

[Aerotech]

Hello,

OK guys its no secret that were in the final stages of making a 99" WS. Pitts Python kit to house a 150cc motor. We are desiging it with not only biplane lover in mind, but to make it a truly nice IMAC plane. Instead of flat tail surfaces we have designed airfoiled tails on the thrust line, a little stretch to the fuselage, lowered top wing, two piece cowl, built up wings etc.

Our goal is to make it fly very much like a monoplane but still keep the biplane feel. But heres where I need some input from alot of you. We are finding making the plane the size we need to make the weights we want, that putting cannisters in it seems to interfere with the bottom wing tube. We could make the plane larger (weight gain) or just run mufflers (unless I get a design idea that I havent thought of yet). I know having planes cannister ready in Monoplanes is easy but this is a challenge.

So Im asking all for input to see if this will be a problem. I know my 42% Velox on mufflers and a 3 blade was dam quite and most carbon two blades never caused me to get bad scores on noise. So step up and let me know some opinions. Im ready to start this plane after Tucson in October. Again you help and guidence will be grateful.

Take Care

John

www.aerotech-rcmodels.com

[Rolling Thunder]

Have you ever seen KS 1090 pipes in a H9 Ultimate. The pipes go over the lower wing tube. It is an easy install.

[Aerotech]

Hello,

Yes but the airframe is smaller than the H9. Were trying to make it somwhat universal for folks to not have to but one specfic product to make it work.

Thanks

John

[xtreem3d]

hi john,
can't help you w/ the cannisters.. but....when you figure it out what is a very realistic time frame that you would have a prototype flown and ready to cut the kits?

[Aerotech]

Hello,

If all goes ok either way. It will be Late Jan 2007 for a kit run. I have all the items/molds finished but the cannister item has been a challenge. I hope the light bulb goes off soon. I just don't to make this plane so far out of scale appereance at the size I believe is an awesome fit for any 150cc motor for either cannisters or mufflers.

Thanks

John

[dmichael]

John,

Well, you probably won't like this answer but it's honest- I highly doubt that I will ever build/own a plane without cannisters. I'm like a reformed smoker- now that my planes are quiet I can't stand the noise of a plane on regular mufflers.

Having said that, I wouldn't purchase a plane that doesn't perform - so, I say design it for cannisters and if you have to stretch it out or enlarge it to do so then that's ok. But, if it comes out too heavy (i.e., for me that means 40+lbs) then I wouldn't be interested.

Dave

[Biff]

John, what about running the cans like some of the pattern plans? Instead of running the completely in the fuse, run them partially exposed. Side view looking at the bottom of the plane, you'd see half of the pipe. There will be those who use mufflers and there are those who will run cans. I personally LOVE an exposed can arangement. Super easy to install, maintain and I think it looks cool. Again, there are guys who refuse to drill a hole in a cowl to adjust the carb.A bunch of us start out that way! Simple and easy to get at are way cool in my book!

[vsnap]

How is Bob at Big Airplanes getting the cannisters in his smaller Pitts...I also know he tried the airfoiled stab and it proved to be not much of a benefit if I remember right. This should be a killer kit as the plane is the best looking one out there..
I already have the 41% from Bob and it will fit cannisters or pipes so I most likely won't be interested, however one for a 100cc might just fit the bill...

[JeremyHolt]

Regardless, Its going to be an impressive plane. Ive seen the drawings Anybody looking for a plane of this nature is going to be in for a treat.

[Aerotech]

Hello,

Good point Dave. Thats why I opened it up for discussion. Sometimes it takes other opinions to make a successful design. We are making leaps with our monoplanes and I dont want the Python to be anything less. I know it will fly awesome, the numbers don't usually lie.

Biff nice Idea I will see if that would work. See my light bulb is already lighting up. Thanks a million for the input. Ive never seen a 150cc with cannisters in Bob's 35% Model 12. The 41% yes but that size puts you into 44+lbs. Nothing wrong with that but for IMAC I know the guys want it less than 40lbs. Side note. I know Bob and is by far the pioneer for the Model 12 design. We all are catching up. LOL


John

[Rolling Thunder]

Maybe MTW 110s with cross over headers would mount completely in front of the lower wing tube. I think this is the shortest setup available.

[Aerotech]

Hello,

In a nut shell its the header distance pushing the cannister back 2" into the lower wing tube. Header is 10.5",then the cannister. Cutting the header back will only make the engine not do as well. According to DA 10.5" is the number. So Im going to try to make the larger diameter cannisters fit just to see. They are 3.125" round versus 2.75. Im going to try this is 3d. Keep the suggestions comming.

Thanks
John

[Flyinrazrback]

You could also run a JMB cannister or BMB cannister which run awesome on about any motor at very short header lengths.

http://www.jmb-brecka.com/index2_uk.htm
http://www.bmb-daempfer.de/

You can check the above links for the cannister information. RC Showcase sells the JMBs and DA sells the BMBs. I think one of those setups would work great.

[Aerotech]

Hello,

Nice suggestions. I know about the JMB they ar 3 1/8" like the MTW. I soaking it all in and I hope to resolve this later this weekend.

Thanks
John

[Flyinrazrback]

Cool deal, I know with the JMBs there are no tuning issues with them, and you can run the header very short, like 4-6" and would alleviate the length problem, while still having the quietness of cans.