scaled x2 Dynajet

Moderator: Mike Everman

Post Reply
gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

scaled x2 Dynajet

Post by gettylee » Thu Mar 21, 2013 2:33 pm

I built this PJ but it won't start,it has .008 pedal valves&atomization fuel system,I'm trying Colman fuel,it has 10,-1/2" intake holes&a 4.25 cc. Any suggestions on jetting size,air psi,etc... will be appreciated! :)
Attachments
IMG_20130320_231954_516.jpg

dynajetjerry
Posts: 465
Joined: Thu Jan 27, 2005 4:57 pm
Antipspambot question: 0
Location: Ohio, USA

Re: scaled x2 Dynajet

Post by dynajetjerry » Fri Mar 22, 2013 5:57 pm

gettylee,
Make sure your starting air blows sufficient fuel into the combustion chamber. The spark must at the exposed end of the plug. Often, contamination on the insulator causes the spark to jump well inside the plug, preventing it from being exposed to the fuel mixture.
Remove the fuel injector assembly, run a bit of fuel line between the metering jet and a supply of water, then blow air into the air line and observe the spray from the injector. It must be substantial for reliable starts. (Don't try this with your fuel because it will be very explosive!) If little or no spray is emitted, the air nozzle is in the wrong position.
Also, it might be better if the spark plug is further forward, out of the high heat zone. Where it now is can lead to overheating of the plug and cause its disintegration.
Jerry
Louder is always better.

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Sat Mar 23, 2013 8:18 pm

Hi there, I tried them suggestions, got some action, but won't sustain running.so far ive got a .060 main jet & .045 cross jet holes. My intake ventury is 1-1/2" & tail pipe is 2" wondering about my fuel/air mixture? Any more suggestions? Thx:)

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Sun Mar 24, 2013 2:25 am

I've made two styles of valves,I see I was able to destroy the triangular shape valve,I etched out some pedal ones&will try them,thay are .008 thick,not sure if the ga. Is OK? Or my jet sizes&air fuel mixture?or go with a needle valve?
Attachments
IMG_20130323_210908_658.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Mon Mar 25, 2013 2:51 am

Added a bit larger valve retainer&needle valve,got to try it now, :)
Attachments
IMG_20130324_204303_580.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Wed Mar 27, 2013 8:23 pm

Still no luck getting it to run, :( I'm hoping some one can spot a problem from the pics,I've been using Colman fuel&methanol, seems like I can supply enough fuel? Get pops&bangs, I'm stuck! & need suggestions, thx Brian :)
Attachments
IMG_20130327_151117_989.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Wed Mar 27, 2013 8:31 pm

Still no luck getting it to run, :( I'm hoping some one can spot a problem from the pics,I've been using Colman fuel&methanol, seems like I can supply enough fuel? Get pops&bangs, I'm stuck! & need suggestions, thx Brian :)
Attachments
IMG_20130327_151151_022.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Thu Mar 28, 2013 12:43 pm

Hello,here is some dim. Tail pipe is 27 1/2" - rev.cone is 5" - cc is 4 5/8" dose that seem like the right size? My pedal valve is .008,can I dubble up pedal valves to equal .016 ? Need help! Thx much! Brian

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Mon Apr 01, 2013 12:21 am

Hello everyone, I got the beast running, it starts fairly well, but seems to need more air in,if I stop the air,she will stop,I put a lap 12 point injector in the cc, to make the lp to liquid fuel transition easyer.I cleaned up my valve holes&changed my tail pipe from 2"to2-1/8, I'm close:)
Attachments
IMG_20130331_182359_921.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Fri Apr 26, 2013 3:46 am

I scaled down my dyna to 2" cc it runs very nice on propane,I will be building a liquid fuel system soon.I built the engine out of the old washer that its mounted to,finally made use out of that old washer! Lol
Attachments
IMG_20130423_211848_607.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Sat Apr 27, 2013 1:09 pm

gettylee wrote:I scaled down my dyna to 2" cc it runs very nice on propane,I will be building a liquid fuel system soon.I built the engine out of the old washer that its mounted to,finally made use out of that old washer! Lol
check out the new paint job&the argus styling,I want to build a small rc v1 with this little 2" PJ ;)
Attachments
IMG_20130426_203320_717.jpg

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Sun Jul 07, 2013 10:11 am

Finally success on my 117mm PJ. Starts&runs nice! Yay:)
Attachments
Screenshot_2013-07-06-20-31-04.png

tufty
Posts: 845
Joined: Wed Dec 24, 2003 12:12 pm
Antipspambot question: 0
Location: France
Contact:

Re: scaled x2 Dynajet

Post by tufty » Sun Jul 07, 2013 10:36 am

gettylee wrote:Finally success on my 117mm PJ. Starts&runs nice! Yay:)
Excellent. What was the trick to getting it going?

gettylee
Posts: 102
Joined: Thu Feb 14, 2013 5:21 pm
Antipspambot question: 125

Re: scaled x2 Dynajet

Post by gettylee » Mon Jul 08, 2013 9:48 am

Hello, I found pulse jet plans from scientific supply, on eBay, they are great plans!!! I didn't build the engines in the plans,but the plans helped me get my engines that I already have, right&running. The plans from scientific supply,are state of the art,New PJ technology! I'd highly recommend them! I bought 10-20-100lb thrust engine plans,I'm building the 100lb thrust engine from the plans now, :)
Attachments
IMG_20130706_173537_722.jpg

Post Reply